Thanks for the invite Chris and good morning everyone. My voice doesn't project super well, so if you can't hear me in the back at some point, sort of like wave your hand at me and I will try to speak louder. As Chris mentioned, yes, my name is Adena Why. I'm from Alameda County Vector Control Services District. So, you know, the other side of the Bay. My doctorate and my degrees are actually in entomology. So, I got my doctorate at UC Riverside from their entomology department. So, I'm trained as a medical veterinary and entomologist and specifically I did a lot of work actually in mosquitoes. So, the title of my talk today is Managing Fleas and Reducing Disease in a Changing Urban Landscape. So, before I get going to actually talk about the diseases and rickettsia in particular, I figured a lot of you probably don't know what Alameda County Vector Control Services does and how it's a little bit different from the other vector control districts.
So, I'm just going to spend a few minutes going over who we are and what our program is. And then that will give you some context about the disease surveillance that we're doing. So, Alameda County Vector Control District is actually part of the Department of Environmental Health for Alameda County. So, we are actually under E.H. and S. So, we are not a special independent district, but we are a special district. So, it makes it a little bit different. And the mission of our district is, at a vector control, is to prevent the spread of vector borne disease, injury and discomfort to the residents of the district by controlling insects, rodents, and other vectors and eliminating causal environmental conditions through education and integrated pest management practices. So, that's all nice and fluffy and that sounds great, but like what does that mean on a daily basis?
So, I'm in particular, we actually have a brand-new laboratory at our district, that will enable us to do more disease surveillance in the county. So, it's about 2,600 square feet. And it's composed of a main laboratory, microbial room, where we do culturing of pathogens if need be, a PCR polymerase chain reaction room where we do DNA testing, a pesticide lab, a vertebrate lab where we process specimens that we bring in from the field. And this will make a little bit more sense in a minute--an insectary room where we have the ability to actually raise insect specimens for testing and pesticide testing in the future and then a large equipment storage room. So, the photo on the top there is of my colleagues [name inaudible] in our PCR room. And then the bottom picture is actually our [inaudible] lab.
So, we have a hood where we comb the animals under, and we do our processing of our vertebrates in that room. So, the objectives of the vector control lab is to monitor the abundance and distribution of vectors within Alameda County. So, we survey for the presence of vector born diseases and then we collaborate with other agencies such as San Francisco and other groups in the means of doing that sort of research. So, what do we actually do in terms of disease surveillance? So, our vector lab, we currently collect, identify and test mosquitoes from the city of Albany only, using PCR for the detection of West Nile Virus to prevent the spread of disease to the public. So, we've actually expanded this year. We're also testing for Saint Louis Encephalitis and Western Equine Encephalitis. We also collect and identify and test ticks, by PCR for Lyme disease and other, and we're going to expand out to doing other pathogens, as well.
And so, specifically we're looking for Borrelia Burgdorferi, which is the causative agent of Lyme disease. And that's the main vector there, which is the ixodidia specific tick, which I'm sure you guys are familiar with. We also do hantavirus surveillance for the county. So, we have a lot of park lands, as you guys know, we have the East Bay Regional Park District. So, we actually go out and we do hantasvirus surveillance in the park system, with an agreement with East Bay Regional Parks and any potential other areas that we feel may cause an issue in the county. So, specifically we trying to trap, deer mice, peromyscus maniculatus, which is the main reservoir and vector for hantavirus. And then we send those blood samples off to the State to be tested for hantavirus. Our latest project and why I'm here to talk to you guys today is the collection identification and testing of fleas. Specifically looking for typhus, so rickettsia typhi and rickettsia felias using PCR.
So, our lab does a lot of other things as well besides just the disease surveillance. So, we have quite a large staff at our district. We just hired a bunch of new staff and we're about 40 people actually in our districts. So, we're quite large. And the way that we work is that every one of our biologists is assigned a different area of the county that they're responsible for. So, along with doing disease surveillance, we also do homeowner calls, complaints, businesses, all that sort of stuff. So, our biologists bring insects back into the lab, that need to be identified from a homeowner complaints or calls. And then also the public shows up with things that need to be identified. So, we do that as well. We also have what I believe is the most extensive wildlife, program in the state.
So, most other vector control districts don't do a whole lot of wildlife removal. Some districts do, depending on their situations. Orange County actually does quite a lot. But we are the most extensive program in the state because we have a USDA wildlife trapper on our staff full time. So, he is permitted to deal with everything all the way up to mountain lions. So, if we have coyotes or whatever, all that stuff, we deal actually with all those calls. So, we're a little bit different in that respect. So, we will trap out wild animals if we have to from residences that are becoming an issue. If we trap the animals, we have to euthanize them. And if we do all of that, we then collect the parasites off those animals for disease testing and we're going to start doing a tissue and blood sample collecting, hopefully coming up.
So, as I mentioned, our program, we deal with a lot of urban wildlife. So, we deal with, raccoons and possums that have gotten into attic spaces in that are breeding. We deal with skunks that have decided to go den under somebody's deck or they're, you know, in their backyard. And we try to get those animals to move on. That's the main part of our program. But if we can't, then we do actually trap those animals out. So, and as I mentioned, if we do trap those animals out, then we will use them for research purposes and then comb them to get ectoparasites such as fleas off of them. We also deal with feral cats, through the county, which I'm sure you guys aren't lacking that in San Francisco County either. So, thankfully that is not a picture from Alameda County.
I would like to state that right now. That's a picture from Florida. Thankfully, it hasn't been that bad. We have had some gnarly feral cat colonies in our county, that were quite large. But it was, it's like individual residences that people have started basically hoarding and collecting cats. So, but yes, I would like to clarify hat's not actually a picture from us that.
You know, I'll have to find that one. I'm sure there is a picture of like a python eating a cat or something. I don't know that we could implement that as a biological control measure, but I will mention that because I'm game. Yeah, it is. So, we, actually we don't go out necessarily and deal with the feral cat colonies on our own. That's animal control. But we do get called by vets and we do assist animal control with the feral cat colonies.
So, we actually will get cats in that had been euthanized already by shelters. And then we collect the ectoparasites off of those animals. That is a picture that my colleague took at one of his calls, of a feral cat colony. So, some other resident had called in to say that there was a lot of cat activity and he went out to find that this person was just feeding all the cats in the neighborhood, in their driveway. So, we do deal with calls like that because specifically it's a potential for a spread of disease. So, specifically on the cats and the other wildlife, we are looking for the cat fleas, Ctenocepalides felis because of its potential for spreading pathogens and specifically, rickettsial diseases, which is why I'm here to talk to you guys today. So, rickettsial diseases, are found worldwide.
And actually this is rickettsial diseases are now considered one of the newest sorts of emerging pathogens. As Chris mentioned, you know, typhus has been around for a while. Everybody sort of forgot about it, you know, it was sort of like measles and then you know, things happened and now the outbreaks are starting to come back. So, it's not that we've eradicated it and actually a lot of the research now, they're continuously finding new rickettisias. And so, it's going to be an ongoing area of research and we're going to be finding probably more and more. So, the infection is actually caused by an obligate intracellular rickettsia. So that's an SCM photo of what the pathogen actually looks like in a cell. And it's transmitted to humans by a number of arthropod vectors. So, it includes fleas, ticks have known to have it. Lice and Mites have also been known to be positive for rickettsia.
So, it's associated with arthropods for part of their life cycle. And it's past to other arthropods, depending on which one, by either transovarial or horizontal transmission. So, what does that mean? So transovarial is when like, say the female flea lays an egg. That egg already contains the pathogen. The larvae don’t need to actually then feed on a host at that point because they can't, but they're already infected. So, when they become an adult fully, they're good to go. They're already infected with the pathogen. So, that's part of the problem. Other vectors of it, seem to need to be able to feed on a host and then transfer it to another host in that way. But as I said, this research is still ongoing, and all of these pathways are still being worked out. So, specifically we're interested in and concerned about flea- borne typhus in the County.
So, flea-borne typhus is a bacterial disease caused by rickettsia Teifi and potentially rickettsia felis. And I'll get into the differences between the two pathogens because we're actually looking for both in Alameda County. So, human cases of flea-borne typhus or reported worldwide but are mainly found in tropical and coastal areas. In the United States, most cases occur in the states of Texas, California and Hawaii. And currently there's about 300 cases that are reported every year. And if you think about it, that makes sense because of the large amount of coastal region that we have here in California and then along the Texas coast, right and Hawaii. So, that makes sense in terms of these are the states that have issues with transmission of the disease. So, what is rickettsia teifi? Rickettsia Teifi or typhus, murine typhus is the causative agent in humans.
So, according to a CDPH or the California Department of Public Health, they feel that Teifi is the only causative agent of human disease at the moment. They don't really recognize felis as causing human pathogenicity. But I'll go into a little bit more about that in a moment. So, it was first, the first species of Rickettsia that was isolated to show to cause human pathogenicity and in cases of flea-borne rickettsia worldwide. So, it is transmitted by the Oriental rat, flea, Xenopsylia cheopis through a flea bite and it is maintained in a flea-rat-flea cycle. So, in normal circumstances where humans weren't involved, it wouldn't be an issue. The fleas would be feeding on the rats, the rats would be doing their thing, then another generation of fleas would bite them, and it would just stay within that cycle. So, the problem is though, is that as you guys know, and as you guys deal with, you know, rats just don't stay in their area. They go where they like and with them go the fleas and then potentially to bite humans.
So, typhus is actually categorized, the two different ones that we're working with in two different groups. So, there is the typhus group traditionally and the spotted fever group. So human pathogenicity of the spotted fever group varies widely between the different species. So, as I mentioned, they're discovering, actually new rickettsias all the time. Thanks to DNA and molecular work, they're able to show that what they thought used to be one pathogen, now there's like dozens. So, this whole area of research is ongoing. And the way they do that is they're actually looking at the differences in the genetic variation. So, significant phenotypic variability. So that just means like how the way the pathogen looks and reacts basically and most members of the group are now considered to be potential human pathogens, but that research is still ongoing. So, rickettsia felias, which is the other pathogen that we're looking at in Alameda County is a newly described, rickettsia and is described as a species of the spotted fever group.
So, it originally, before they thought that everyone that got sick was sick with Rickettsia Teifi and they just thought it was the one pathogen. But more research has been done and now they've realized that there's at least two and there's actually dozens more. So, rickettsia felis requires a vertebrate and an invertebrate hosts to survive and reproduce. So, it can't just survive on its own in the wild. And there's actually two different transmissions cycles that we're concerned about. There's an urban cycle and there's the suburban cycle of transmission. And I'll go into that in a little bit more detail in a minute. So, rickettsia felis is associated with the cat flea, Ctenocephalides felis, which is why we're trying to collect them throughout the county and then survey for them. And it's the first recognized as a human pathogen and the causative agent of flea-borne spotted fever for the first time in 1991 in Texas.
So, it is the only defined biological vector of rickettsia felis. So, what does that mean? Is that even though it has been shown that other arthropods, other ticks, other flea species can carry it to date because of the research that's been done, it's the only one that they know that has actually transmitted the disease. So that's why we're mostly concerned primarily with the cat flea. However, the rat fleas, [inaudible OPSIS] is the main vector of the other typhus, murine typhus, Rickettsia Teifi and has been shown now to actually harbor both pathogens. So, it is an issue because of the ongoing disease transmission. So, the flea-borne typhus cycle. So, this is basically, you know, what you guys need to worry about and be concerned about when you guys are out in the field and working because there are actually two different transmission cycles.
So there's the urban cycle, which historically is just Norway rats. So, the fleas are biting the Norway Rats. The Norway rats are, you know, burrowing, tunneling doing their thing. And what happens is, is that sometimes there is a you know, accidental transmission to a human. So, you know, as we mentioned, as you guys know, rats just don't stay in their burrows. They don't stay only with each other; they will move on. So, with that, then they can accidentally bite a person and then transmit the disease. The suburban cycle includes possums and feral cats. Isn't that great? Right. So, the issue now that we're seeing in California, and this was first discovered in Southern California, and actually a lot of work done by Orange County Vector Control District is the suburban cycle involves the transmission to possums and feral cats. And we think actually now that the possums at least, and potentially the feral cats are actually reservoirs for having the pathogen.
So, basically now the cycle is just getting bigger and it's getting more evolved and we have to deal with more and more vectors regarding this. So yeah, Chris. So, yeah, so we are, like I said, we are interested in the cat flea, but we have to keep an eye on both flea species. So, in the urban area, traditionally it was the rat flea or Xenoopsylla cheopis that we were having to worry about because it is also the vector of plague. And so historically that's pretty much what everybody cared about and what everyone worried about because you know, wiped out half of Europe, you know, several centuries ago. But now the issue in rural areas and actually also in urban areas now is the cat flea because the cat flea is pretty much ubiquitous and everywhere.
So, cat fleas are cosmopolitan. So, they are literally found worldwide. And these are the fleas that are commonly found in your home and are associated with your pets, so they accumulate and organic debris. And these are the ones that, you know, if your dog or your cat comes down with a flea infestation, you take it to the vet, they're like, oh, here, put advantage on them. Blog. It's to control for these guys, mainly the cat fleas. So, however they don't just attack as the name implies, cats. That's actually most flea infestations on dogs are actually a cat flea. And then they also readily bite possums, foxes, raccoons, rats and humans. So, when you have a flea infestation in your home, you know, and you need to call pest control, if you don't, you guys do it yourselves. Basically, that's what you're dealing with is the cat flea and they can cause severe bites and reactions as well. So, the difference with the Oriental rat flea is the oriental rat fleet is the chief vector of bubonic plague and the other typhus. So, Rickettsia Teifi so, and it was introduced worldwide with Norway rats and roof rats. So, this flea is also worldwide now because its host has moved, and the infection is transmitted by the bite of the flea. So, the flea needs to be able to bite on you, be able to, you know, extract the blood from you and then through that process, that's how you become infected.
You know, it depends on the last time that they took a blood meal, but I think it's about a couple of weeks, but it depends on the species. Yeah. So, I think because it depends on how long it takes for them to metabolize that blood. So, I think they can, yeah, last for a few weeks. So, that's why I usually like treatments. You can't just do one treatment in an area, you need to do multiple treatments in a house, right. You can't like flea bomb at once and expect to call it good because you may not actually get all the adults at that point and the host also need to be removed from the area. So yeah. Yeah. So, in Alameda County, as I mentioned, we deal with a lot of wildlife. So, we actually have quite a lot of sources of fleas within the county. So because we are permitted and we actually do wildlife calls and nuisance wildlife calls our three main vectors that we deal with specifically because they vector rabies, but now we're also interested in the potential of them to have fleas and then transmit disease are raccoons, skunks and opossums.
So, these are actually our service call numbers for last year. So, we dealt with a little over 300 possum calls. So, this involves potentially multiple calls out to a home because a possum has set up shop in somebody's attic or under their deck. Raccoon calls, we had almost 800 last year, and skunk calls. So, you know, people tend to get a little upset when it's breeding season and the skunks have decided that their backyard is mating haven and are gone ballistic. We get a lot of skunk calls, especially in this time of the year. So, and then when the babies are out. So, we had almost 570 calls last year and this year is on par with last year in terms of our workload. So, the other big source of fleas that we have in Alameda County and with you guys being in San Francisco, this is not novel to you are in homeless encampments. Right?
And, so we have varying sizes of homeless encampments as I'm sure you guys do here in the city, and this is actually a photo that I took. So, this is one of our largest encampments. You know, conveniently a lot of them located right near the Bart tracks or under the Bart tracks, good times. Right? So, yeah, so that was actually of an encampment that has actually been cleared out and raised at this point. It got bulldozed, but this was a location at East 12th and 23rd. So, part of the problem that we have, which I'm sure you guys have here as well, is illegal dumping. So, the residents of the camp actually have signs up that say, please don't dump, you know, we live here, but it doesn't stop anyone. You know, they roll up at night and they just dump all their stuff on the curb. And even though the city has implemented pickups, you know, will, this will be clean, and we'll come out the next morning and there'll be a new pile of crap on the curb. So, what that means is that harborage galore.
So these are people that want to give stuff to the homeless people?
Yeah. So, yeah, before I started actually working in this, you know, I sort of also had the same thought process. It's like, Oh, you know, these people need resources. You know, they don't have the ability to do it, but there are so many advocacy groups, groups now that actually can get things to the homeless like in a sort of properly controlled manner. That, and a lot of it also is people just don't want to pay the dump fees. People are cheap and so they assume no one's going to notice another pile of garbage at the homeless encampment along with all the other garbage that is being generated by the homeless encampment. So, the other issue we have is we have a lot of food that gets dumped at the camps. So, this was one morning out at one of our camps where we showed up to do trapping and we were like, oh, that's nice.
There's like potato chips. I have gone out to a camp one day and found an entire box of raw steaks, which cool, you know, thank you for dropping them off to the residents. However, if the residents do not feel inclined or do not cook all those steaks today, "A", they have no refrigeration. And two, you just bet every Norway rat in like a five-block radius or more. I have also gone out and there was an entire Thai food buffet. Somebody had left from their office that I don't know, that 50 people decided not to come into work today or whatever happened. And there was like, it looked better than honestly the lunch that I had that day because I think I'd had leftovers, but literally there was like an entire Thai food buffet that was just somebody who had put on tables at one of the homeless camps.
And I was like, cool, well, let's see if we can manage to catch rats with all this competing food resources that are out here. So, that's an issue that we have-- is that we have a never ongoing supply of harborage and food that shows up. A picture that I did not take, which I wish I had one day when we're out of the camps, if somebody had dropped off a whole bunch of bagels and the bagels were stale, but that didn't stop the rats. So they actually, one of them had actually tried to pull it in its burrow and it got stuck so it was wedged in the burrow entrance, but it, it hit like eating around it, trying to like get it small enough to get it in and then gave up. So, we have lots of things that we deal with.
And because of that, so as you guys know, because you're familiar, right? Once Norway, rats come above ground, they don't go back. So, as I explained to homeowners and stuff, when I deal with it, is that if you basically got lead out of the sewer into Hawaii, do you have any inclination to then move back in there? The answer's probably no. So, these rats don't do that either. So, once they come above ground and they set up shop, they're burrowing and they're breeding now above ground. So, we have above ground Norway, rat populations, citywide in Oakland and also in other areas of the county. So, we deal with the burrowing and so with that, we started a program of live trapping these rats out to try to control them and get a handle on their numbers.
So yeah, those are rats. So, we live trap them. So, these are rats in the cages. I am raised in Oakland, so I feel that I can say this Oakland as special, where there isn’t no other place like Oakland. So, when people ask me how big these rats get, and I said larger than a Chihuahua and they'll kick your Chihuahua's. But because, yeah, so the biggest Norway rats that we have pulled into date, we're almost two pounds a two-pound rat. Yeah. You guys might have bigger, like I'm in the process, I'm actually going to buy a scale for our lab because I actually want to see. We have, you know, we get variations of sizes when we trap, we get juveniles, we get adults, we get breeders, we get non breeders. But our biggest rat to date was a male, obviously had been breeding, yeah, almost two pounds. And we've had a couple of them like that. So yeah, when we pulled rats, they're like, oh my God, those are big. Really, that's nothing. We get bigger ones, sadly.
If they don't kill the rats what do they do with all of them?
Nobody does anything actually if we don't. So, unfortunately the City of Oakland, and like I said, I was raised in the city of Oakland, you know, my family is still there. It's just the amount of issues that Oakland has, they don't have the resources to deal with it. So, essentially, it's become sort of one of our main programs is to try to control a lot of the rats in the homeless encampments if we can. Because the problem is, is when the encampments are cleared, the rats moved to the neighborhoods. So, it actually, you know, it's sort of on us and because we are vector control, we do have the ability to go out on the properties and do things that other entities wouldn't necessarily be able to do legally. So, it's sort of unfortunately become something that we now have to deal with on an ongoing basis.
And you eventually exterminate them?
Yeah, I'll get into that in a second. Yeah. So, but yes, sir?
Has there been any talk to use dogs for rat control? There are certain breeds of terriers?
You know what, actually our wildlife trapper also breeds dogs. And so I had talked to him about that because he doesn't, he hasn't been terriers, but we did have that discussion because if you haven't seen it, there's kind of a cool video out from New York City where there's just sort of like a vigilante group of homeowners that they basically let their dogs loose in the city at night to go rat hunting. And I was like, Hey, we can have dogs around the office.
They do a better job than cats.
Yeah. Because we do have people who ask, oh, should I get a cat? And I said, well, if the cats that I've dealt with are any indication, there's varying levels of mousing. You know, my, one of my best friends, cats barely moves for its food bowl, you know, so it's like a rodent running by it is not an attractive if she's not even going to get up, you know.
So, so I tell people, if you want to do your own IPM and you want a cat, and this is your excuse you far be it from me to tell you no, but if you think that this is going to be effective in lieu of calling pest control or doing your rodent proofing, the answer's no. So, um, yeah, it's different. So, Norway rats, ratice norveticus, are also commonly known as the sewer rat and the brown rat. So yes, I know you guys do have Norway's in San Francisco, and traditionally, you know, if all goes right and you don't have breaks in your infrastructure, they stay below ground and that's generally where they are. However, when you do have those breaks in infrastructure, as I mentioned, they come above ground and then they stay. So, they were actually introduced from China.
And they are now considered one of the biggest pest species worldwide. Just because they're so adaptable and because thanks to humans, they have been introduced to every continent, save Antarctica at this point. I don't think they're on Antarctica. I hope not. And I hope they freeze to death if they are there. But um, yeah, I believe it's every continent but Antarctica. So, they are commonly found associated with humans and are prevalent, especially in highly urbanized areas like Alameda county, like San Francisco. So, Norway rats are generally larger in size than roof rats and wood rats and they're good swimmers and they excavate extensive burrowing systems. So, as some of you probably come in contact, especially those of you guys who do the parks and the landscaping and stuff like you guys see burrows, right? And there's not like a burrow, there's burrows right, all over the place.
So, you know, one of the sites that we're dealing with right now with control, is actually a little bit disconcerting because the Norway rats have borrowed so extensively that I'm actually a little concerned that the nearby sidewalk is going to start collapsing at some point because the ground around when we found this problem is like Swiss cheese with the burrows. Like I'm not that big and I was sinking like standing out. We went to go see and we were standing above the burrows and one of my coworkers is sort of like your size. And he was, he just went to him. He was like, "yep, there's burrows." Because their borrowing is so extensive and they're such good diggers. They also, because of that though, they also do carry a lot of different active parasites. So aside from the fleas, they actually harbor mites as well and lice and we're actually going to, we are doing research into that as well.
Because of the potential of disease transmission to the residents of the homeless camp as well as other people because Norway rats do get into homes. We deal with a lot of Norway rat calls actually in homes. So, it's not just roof rats. Traditionally, I think it may have been more so, but now because you know, San Francisco's sewer system is old Oakland sewer system is, you know, failing in a lot of parts of the city and other parts of the county. You know, the rats were coming above ground, so it's not just roof rats anymore. So, this is a map of the homeless encampments in the City of Oakland. So, since you guys are all from here, you know, this is not a novel concept to you.
They're chewing lice, so I don't have a picture in this, but we're actually doing research on it right now. We're actually doing, it's a program that I set up that we're actually surveying to see sort of what a normal ectoparasite load is on these rats. Because right now we have absolutely no idea and we also don't know if it's seasonal, which would make sense though because they are arthropods and insects that there's a seasonality to them, but we literally have no idea at the moment. Right now, it seems that what we've picked up is one species of louse in particular. And then like one or two species of mites. But, we're actually a little short staffed at the moment. So, my data processing is a little bit backed up and stuff, but we're trying to get a handle on sort of what they quote unquote normal louse load, mite load, flea load on some of these rats and it varies.
So, we'll pick up rats, actually the rats that I processed this week, from one of our camps where some of the rats had like 10 lice on them. And then one adult that I was combing, the lice were just flying off and there were hundreds. So, and I was just like, and we've had that before, but they're from the same camp, they're from the same area. And it's, we haven't really established yet because sometimes the juvenile rats will actually have more ectoparasites on them, like fleas and things. And so, we were thinking that maybe it was an issue that they just don't know how to groom themselves well enough. And then the older rats, this one also had injuries on it. So, I don't know if it was just because it was compromised already that had had, but, the first ones that we got in that look really gnarly actually, we thought that they had been fighting with each other because of the amount of scarring and damage on their backside. But when I started combing it, I realized it was lice, they look like they had mange, like they were just missing for like in chunks, like down their backside. And it was the lice we think that we were pulling off. So yeah.
What type of lice are you finding? It's not [inaudible] lice is it?
No, no, it's a, it's a, I'm blanking out on the name at the moment. But it's a no, from what we've identified, it's a louse species that is associated with rodents. But what we don't know is whether or not yet if they will host switch given high enough, like if they necessarily, that they will, not necessarily that they will transmit disease to humans, but whether or not when the louse load gets high enough, like most insects, they'll just move, you know, if things become a little crowded, they'll just go next door. So, but this is a map of the homeless encampments in the City of Oakland. So, pretty much the minute that this map was made, and this map was old. This map was outdated because the camps move all the time. We do have camps that have been established and or have been there for several years.
When I talked to the residents, there are some that have lived in particular camps for five years, whatever it is. But then we have new camps that pop up all the time and we do get camps; they get cleared out. So, currently we are trapping at the larger, more established camps, within the city to try to get an idea, as I mentioned, of the differences in the rats and the ectoparasites that they have. But there's, at any given time, and I'm sure this number is probably not super correct anymore, there's 40 active camps in the city at any one time, and that's just the city of Oakland. And we do obviously, as you know, have homeless encampments, in other areas of the county. So how do we actually get, the rats, excuse me, out of the camps.
So, we actually use live traps. So, I don't know if any of you are familiar with National Traps from Tomahawk. But that's what we use to trap the rats out. Because we do need the routes to be alive in order to get the ectoparasites on them because once the host dies, insects are very, very good at knowing the minute that body temperature changes and they'll start leaving. So, we can't put out like snap traps and then like, just kill the rat off and pick it up the next morning because the fleas and stuff we'll have moved off by then. So, we do have to pick them up alive. So, in order to bait with them, we bait with a combination of mackerel and peanut butter. And we found that this is really effective because "A," you know that it's not a wives tale though, but you know, rodents like peanut butter, it works.
But then the other thing is, is that the mackerel is super smelly and it's super attractive. Because if you're competing with a box of raw steaks, right? And you're like put, we tried a couple of different baits, right? So, we tried it out in corn it and it was just like, that's nice. You know, like they've got bagels that got delivered yesterday, right? Like they're not going for that. So, but what we did find is that the combination of the peanut butter in the mackerel seems to really be effective. So, when we were trapping is also not just like put a trap out and go for it, right? We also, your trap placement is very, very critical to your trap success. So, we look for signs of activities. So, this is, sorry, it's a little small for you guys, but that's Norway rat droppings.
So, we look for active of activity. So, we look for fresh droppings, we look for accumulation of droppings and all these little black things are all droppings next to a concrete piling. So that's what we're looking for. We're also looking for paw prints or footprints. So, all those little brown things. So, this is, wood for building and that was at one of the camps and all these little brown dots are all Norway rats that have been running all night long. We're not short of rats, at all, in these areas. So, we also look for signs of active burrowing. So, you know, here's a burrow and they love burrowing at this interface of where the concrete and the fence line in the dirt comes together. I'm sure as you guys are aware of, so we look for active signs, you know, the clean burrows.
And then obviously this one, the dirt has been kicked out and that's where we'll go, and we'll place our traps. So, the other thing that we found that is very effective for our program is that you also need to hide the traps because as you guys know, rodents are neophobic or phobic to anything new in their environment. So, if you just drop a trap out, even if it's baited, there's not a guarantee that that rat won't notice it and then avoid it. So, what we do is we actually use items from the camp, and we covered the traps. So, it masks the smell of our presence and then the rats don't recognize it because it smells like the camp where they'd been running. So, what we do is we use, and this is my colleague Michael Mooney, some of you might know. So, this, Mike is grabbing different things.
So, we use clothing, bedding, you name it, you know, around the camps to hide the traps. You know, we'll use other pieces of plywood and stuff. You also need to talk to the residents of the camp. So, you know, working in homeless camps is very different. It's not for everyone. And it is dangerous. So, you know, we're never out there alone. We're always within eyesight of each other. And then the other thing is, is that you have to talk to the residents. They generally like us, because we're not trying to arrest them. We're not trying to get them to move out. We're not trying to tell them to clean up anything. We're basically trying to trap out the rats that are destroying their stuff. So, they're generally super happy to see us. They like love us, they want us there on like a daily basis, you know.
And so we tell them, it's like, hey, you know, we will do what we can. And then we also try to educate them and get them to work with us to reduce the amount of harbors and the amount of food. You know, that works better than not in some of the camps. So, I'm going to camps are more well managed than others. Others are not. But we do what we can. So, we covered the traps with the bedding material and then the traps are left out overnight. So, we set the traps in the afternoon and then we go back the next morning to pick up the rats. And so, this is a picture of our live traps and every single one of those has a rat in them. Our best success rate to date is we've gotten three in a trap, three live ones.
So, you know, usually we get one, but sometimes we get to first, we get three in there. And as I mentioned, they do come, we need to bring them back alive to lab. So, we do have an approved euthanasia protocol that we use. So, we gas, the rats with CO2. We do put them when we're collecting them into a large black plastic bag, just because of sort of the, I hate to use the word, but the optics of it, right? It's like you just, it's, you just don't want the questions right from people being like, Hey, what do you do? You know, like the residents sort of know. But you know, there are people driving by, you know, and it's like, oh, what are you guys doing? You know, we're out there and safety vests and stuff. So, just to minimize like sort of weird pictures and comments from people who don't understand what you're doing.
We put the rats in the bags and then we move them into our trucks. So, in order to knock down the ectoparasites, because obviously we don't want our staff to become infected or anything transmitted to our staff while they're working. We, you can either use starter fluid or we use a PTPI [Inaudible] to knock them down. So, once the rats are euthanized, we spray them with the PI to knock down the fleas and the other ectoparasites. And then we let them sit for one hour before we comb them for the act of parasites to make sure that it's been effective and that nothing is flying off. Jumping off when we're going to process the animals. So, how do we actually find out if these animals do actually have rickettsia? So, we comb the fleas. So, this is a picture of my colleague taking a flea off of an opossum.
So, we comb them to get all the fleas off and then we actually identify those fleas to species. We pull those fleas together for DNA processing. So, we disinfect the fleas that are washed with 70% ethanol and distilled water to clean them. And then they're prepped for PCR analysis. So, in order to do the extraction, the DNA extraction, essentially the fleas are pulverized to release the DNA. So, they're basically just like minced into little bits so you can get the DNA out. And then we use what's called a KingFisher duo system to actually do the PCR. So that's, my colleague Natalia Federova who is amazing and she does a lot of our molecular work and so she's actually working on the DNA extractions. So, at that point they're run in a real time PCR assay to actually detect the pathogen.
So, the kit that we use-- part of the issues with the rickettsia and rickettsial research is that because a lot of these rickettsia are so closely related, when you test them, sometimes genetically you can't tell which one you have, you don't know what species you have. It just comes back as saying positive for the pathogen. So, because of that, we actually have to send them out for sequencing to actually identify what we have to make sure we have the correct one. Because we don't, you know, we want to be good about our data collection in our research and we don't want erroneous confirmations of pathogens we don't have in the county. So, we amplify the samples and then we send them off for sequencing and then we get those back to confirm what we have. So, these are the some of initial findings from last year.
at three of our biggest homeless encampments. So, one that was on 23rd, which was that giant pile of garbage that I showed you guys. So, at that time we had trapped out 32 rats. 27 of those rats had fleas. So, six pools from six different rats. So, different rats that were running through different parts of the camp. Every single one of those came back as positive for rickettsia felis. We also got one feral cat from that camp and that cat had fleas on it and six of the pools off of those cats. So, four of them were positive for fleas. So, that's the other issue with doing the disease testing is you can't just test one flea and say, Oh, I've got it, or I don't. Sometimes that one flea may not have enough be able to show. So, you need to actually have multiple fleas, in order to do the analysis.
It works better. You can do it on one. But generally, we try to get the most fleas that we can. One of our other locations, nine out of the 33, Norway rats had fleas and one flea pool came back and it actually was a different species. So, it's not rickettsia felis or rickettsia teifi it's another one that we found out we have in accounting. And the third location, which is interesting because this location has rats going all over the place. We didn't get any fleas. We have no idea why. So, that's the thing. It's like these camps are separated, geographically. And so, we think that there are actually distinct sort of populations of Norway rats because they're miles apart. These rats are not running from camp to camp. So, the ectoparasites that they have on them are different as well. So yeah, Chris?
I'm not sure exactly what that means. The six pools slide. Do you have any way of estimating kind of percentage?
Yeah, that's what I'm getting to. You're killing my punchlines, Chris. That's okay. Okay. So, this is an overview of actually what we found in terms of the disease prevalence in the county. So last year we did 11 possums, 12 feral cats, and 44 Norway rats for a total of 67 animals and 665 fleas off only 67 animals. So, what that means is there was an average of about 11 fleas per feral cat that we got in. Six fleas per rat. And opossums are our favorite because they are loaded with fleas. And so, an average of 26 fleas per possum that we bought in. Opossums, if you don't work with them on a regular basis, just because of their habits and what they eat, they are covered in fleas generally. So, our highest freeload load off of one of our possums was like 300. Yeah. So, just be careful guys, if you guys are working with possums that yes, they have fleas. Yes sir?
So, the opossum is the only one that is indigenous?
No, actually possums have moved. They were originally from the east coast and they moved west. But technically at this point we considered them more or less native because they've been here since like the 1,800s. So, but yes, so technically they were east coast animals.
So, they aren't actually a native species?
To California, no. So, actually the fox squirrels are not native either, the grey squirrels are. So yeah. So, in terms of testing for the cat fleas in the county for rickettsia felis, so out of 12 animals, feral cats that we tested, we tested 32 pools of fleas and 18% of those came back as positive. For Norway rats, we tested 20 pools of fleas and 45% of those came back positive. And for opossums, we tested, over 270 or 271 fleas and 31% of those came out positive. So, countywide we have about an average of 30% of our fleas are infected with rickettsia felis. But as you can see, it actually varies per host animal at what your actual infection rate is.
Yeah. So, I'm going to get it. Yeah. So, I'm going to get into that in a bit because there's a bit of a debate depending on who you talk to. Right now, CDPH and CDC consider rickettsia teifi as the only one causing human pathogenicity. But there are documented cases worldwide outside of California, where felis also causes human pathogenicity. Yeah. So, as I mentioned before, we are also looking for oriental rat fleas because they are also the vectors of plague. But we're looking for them in terms of rickettsia as well. And so, what we found is even though we had 226 fleas come in, only one pool was positive for a very low infection rate of less than 2%. So, this seems that our data in Alameda County and corresponds with data from other areas where the cat flea is the main vector and not the oriental rat flea.
The oriental rat flea is still the vector for plague, but not, it appears for rickettsia at this point in time. So, to date, we have found positives from seven cities within Alameda County. So, we have positives in Oakland, Alameda, Pleasanton, Hayward, Union City in Newark and Fremont. And we're working on getting on data from the rest of the county. But as I mentioned, our wildlife program, we don't specifically go out and target at this point to trap animals out. So, basically, we have to wait until we get nuisance calls and things like that because as we explained to the public, our mission is not to eradicate the wildlife from the county. That's not our goal. We will help them move off of your property and stop them from causing damage, but where you're not just going to trap all the animals out because you don't really want a raccoon and going across your yard and things like that.
So, the reason that we became interested in this at all is because we do have a historical prevalence of rickettsia throughout the state. So, Orange County and L.A. County have had outbreaks in the last few years, but there's also historical prevalence of it and San Bernardino, Riverside, Sacramento in Contra Costa County, which is on the other side of the border from Alameda. So, these are the numbers from November 2018, regarding the outbreak in Los Angeles County. So, as of that date, 70 cases in la, there were 15 cases in long beach and 18 cases in Pasadena for a total of 124 human cases that had been reported to the state. L.A. County vector control and along with CDPH, we're trapping Norway rats out of, I think they were targeting some of the homeless encampments. None of them came back as positive for Murine Typhus and they were getting an average of nine fleas per rat that they were trapping. They did also pick up the oriental rat flea and tested it. And that did actually come back as positive for rickettsia teifi, which also corresponds to the data that we know is to be correct, that it will transmit that. And that was off of Norway rats.
So, Because of this Orange County vector control has had a typhus program going on for quite a few years now, ever since the outbreak started in Southern California. So, we didn't actually invent the wheel on this. We went down to Orange County to do some training to see what they were doing. So, they have a full-blown typhus program that they're doing. They've actually done quite a lot of research into it. So, if you're interested in looking at what's been done to date in the State, Orange County is actually the one that's done a lot of the research so far. They've actually tested cat fleas from opossums and domestic cats in residential areas. And they've detected both Felis and Teifi in their cat fleas. And then the fleas were actually predominantly infected with felis and not Teifi. So, what does that mean?
So, right now we're having significant gaps in terms of our understanding of the human pathogenicity of felis. So, as I mentioned, CDPH and CDC tend to only think of rickettsia teifi or murine typhus as causing human pathogenicity. However, in Orange County they collected almost 600 fleas from opossums and cats and found that the majority of almost 30% of them were positive for felis and not Teifi. So, if all those people were getting sick, but only to less than 2% of your fleas in the county are positive for the one pathogen, how does that work? Right? It's like, don't you need a whole lot more fleas than that, which they're not finding to be positive. They also did another study where they worked with the Department of Public Health and they actually got the addresses for the human cases and they trapped out from there trying to find the host animals that were potentially infected with the diseases.
And what they found is that 53% of the fleas that they picked up off these possums had rickettsia felis and only 3% had Teifi. So, it's very interesting in terms of the disease, epidemiology and ecology of this, of what actually is going on and what's actually being transmitted to humans. So, these are maps of the distribution of rickettsia felis and rickettsia teifi worldwide. So, the gray areas are all the areas where they have collected arthropods. So, not just fleas but ticks, lice, mites and other things that have been positive to carry. rickettsia felis. And as you can see, it's a pretty good worldwide distribution. You know, it's most places, save, you know, a big empty part. And you know, in China and Russia, but a lot of, definitely all throughout North America and a lot of South America. The black part are rickettsia felis positive arthropods where have also been documented human cases of sickness.
And you can see the map for rickettsia teifi in red has a much smaller distribution worldwide of where those cases have been. So, even though to date, you know, a lot of the larger organizations such as CDC and CDPH are just considering this pathogen as causing issues. A lot of that tide seems to be changing a bit depending on the researchers you talk to you. Because this map is much more substantial, and it's tied to cases that they know of. So, this is a study that was done. I'm showing the worldwide cases of rickettsia felis throughout the world. And the distribution of felis is probably coincides with the distribution of the flea as the cat flea got moved worldwide with humans taking their dogs and pets and other animals with them. The fleas went with them and so did the pathogen. So, because the cat flea is so commensal, so used to being with humans, that that's how it got spread worldwide. So, this is a study done by [inaudible] Incluso with, they looked at confirmed cases of rickettsia felis in different vertebrate hosts. And the issue right now, and the ongoing research has to do with the fact that it's not just dogs and cats and opossums and rats that have been shown to have the animals. This is a case where sheep have been found to have the pathogen, goats, horses here in the U.S., so far, we've confirmed the opossums, cats, rats, mice, a brown pelican of all things and dogs. Okay. Yes sir?
What about gophers, moles?
You know, the literature that I've seen to date haven't listed them, but I think that's basically because people aren't looking yet. You know, we are starting to think that it's pretty much widespread. But the issue is, is that just because say like a flea has the pathogen in it. If it's not at a high enough level, even if it bites you, it may not be enough to transmit for you to get sick. But that doesn't mean that it doesn't have it. So those are all the issues that are still, people are still trying to research and trying to figure out, but the more people are looking, the more and more that they're finding it is the situation.
So, yeah, for us, you know, the paper didn't really, so that's the thing, you know, like horses manifest differently than humans and other animals. So, they didn't say whether or not, the animals actually were sick enough to be put down, but they just said that when they tested their blood that they found it in there.
Were cats tested there?
You know, I'm not really sure about that. So, I think some of the issues, which I'll mention in a minute too which is the same with humans, is that people aren't looking for it. So even if the cat does present with something, they assume it's something else. So, this is another study that was done by our data all in 2001 showing the different insect host or carrier vectors for it. So, the biggest one that's been found in the most countries, and sorry I know I don't expect you guys to read this, but is the cat flee to date is still the largest vector of it. However, there are other flea species that have been shown to have rickettsia felis a few hours and that includes the rat flea [inaudible] which is also plague and human flea. And here in the U.S. they've also found that a soft tick had it. Now, the soft tick is not the main issue that we're dealing with, but it's just something for you guys to be aware of as well as all ticks that have other pathogens.
So, what does that mean in terms of being transmitted to you guys or anyone who's working in these areas? So, they're transmitted via the bite of the flea to a person through the saliva. So that's somebody who's having a severe reaction to all their flea bites. And the issue with typhus, murine typhus and flea borne typhus is that the clinical symptoms are the same as like 2000 other diseases. So, you come down with a fever, you come down with fatigue, aches and pains, a headache. Something that is more distinctive is what's called a maculopapular rash. So, you'll get a rash all over the place, but some people who are prone to getting rashes like contact dermatitis, you can get that from not having your laundry soap wash out of your clothing either. So, the issue though is that, and there's also what's called an eschar.
So, it's kind of like a wound looking like area. So, the thing is though is that people can have some of these, all of these are only a few. So, when you go to the doctor and you present with it, you know, the doctor would be like, oh, you have a flu, you have cold go home. You know, they're not looking for it. They're not testing for it. So, that's a lot of the issues right now with the clinical diagnosis on the human side is because the tests that come back just show that it's positive and they assume that it's positive for Rickettsia Teifi. So, it may be Teifi, but it may be felis, but they tend to not do the extra testing that needs to be done to find out which pathogen it actually is. So, it's just something to be aware of that we think that this is actually more prevalent than it's been in, you know, reported to date basically because nobody's looking. The medical community is just not aware yet and they're not really looking for it or testing for it.
So, just to summarize our, our district's flea borne rickettsia project. We've been doing this since January 2018 now, and it's going to be ongoing for who knows how long. We've had fleas from more than 70 animals and actually quite a bit more of that to date. 200 flea pools were tested. So, to date, as I said, we have seven cities that we've confirmed. We have the pathogen in it. Rickettsia Felis was found in both cat fleas and oriental rat flees from feral cats, Norway rats and opossums. And as of today, we have not yet found Rickettsia Teifi in our county, but we're still looking.
That was, no, that was the oriental rat flea that had felis not teifi. Yeah. Yeah. So, I'm going to switch gears for a second just because Chris asked me to talk a little bit because this is the IPM group and because what you guys do for a living, of how you guys can control fleas or try to in your areas that you're working because of all the restricted usage on all the pesticides and stuff that are in insecticides that are out. So, if you guys come in contact with fleas, like, great, what am I supposed to do? So, just to review for a quick second, you know, this is the flea lifecycle. So, you actually need the male and female fleas to mate. Once they do and the female takes a blood meal, she's taken that blood meal because she needs the protein to make her eggs.
If she doesn't take the blood meal, she can't manufacture them. So, once she does that, she'll start manufacturing the eggs, in two to four days or one to two days, excuse me, once she's eaten. So, she can drop up to 25 to 50 eggs per blood meal once she starts going. So, you know, that's how come that they can, their numbers can accumulate so fast once those eggs hatch, fleas are what are called metamorphosis, whole metabolas insect. So, if you familiar with the butterfly, right, you have like the Caterpillar and then you have the Chrysalis, right? And then you have the adult. Fleas do the same thing. It's just not as pretty, essentially. So, you know, because their larvae look like that. Right? Like nobody's going to be like, oh isn't that, you know, most people aren't going to say that.
Cute. Right. Same thing though. It's a larva. It's a caterpillar. Essentially there's three stages. They pupate and then they emerge as adults. So, what does that mean in terms of control? So, you need to determine the point source of the fleas. Where are the fleas coming from? Because they have to be feeding on a host. They don't just show up out of nowhere if there's nothing for them to get blood out of. So, is that wildlife that they're feeding on, right? Is that feral cats potentially that they're feeding on or the companion animals? Right, because a lot, as I mentioned, you know, most flea treatments for companion animals, domestic dogs and cats are for cat fleas. So, you've got to figure out where they're coming from. And then at that point if you can remove the source, that's what you want to do. So, whether or not that means that you trap out the animals to remove them.
So, the adult fleas no longer have anything to feed on. So, you can break the cycle, or I don't know how many of you are familiar with exclusion for these animals. So, in our district, we do this a lot. So, this is a one-way door for a raccoon. So, the way that works is you attach it to the structure. So, whether or not they're like underneath the sub-area of the house underneath the deck and then you make it so that's where the animals entering. Or, I'm sorry exiting, but they cannot re-enter. So, you do it so that they come out and you know, as long as you do it correctly, they cannot then go back in and then you can seal off that area. So, then that stops the problem. So, that's something that you can do is, you know, put up, remove or exclude the animals.
But then another thing that you want to do if you can, is also remove the nesting and the bedding material. Because the larval fleas can't develop without the food source from their parents. So, larval fleas, what they're eating is actually the old dried blood, the excess blood that the adults are fed on. So basically, what they're doing is that, and I know this sounds gross, is that the adults basically, I know, she's like, oh my God. (Laughter). They essentially poop out the excess blood into little dried pellets and that's what the larvae are eating. So, if you can get the animal out, yeah, it's delicious. Right? So, once you get the animal out, if you remove that bedding material, you'll remove the reservoir for that food sources so, this development can't continue. So, if you have to do flea control, what do you want to do?
You can use an insecticide or an adulticide, right? So, you want to use like an IGR if you can. So, if you've got a big area for those of you guys who are managing the parks and stuff and you've got like a big lawn area, you can power spray it. You know, with that area, if it's a smaller one, you can use a backpack sprayer or a hand can and go out and treat. For us we can do it under vector control exemption. So, for the people in public health, you guys probably are allowed to do it too. Those of you guys who are park managers, you know, you guys may not be able to unless you can work with another group saying that it's like a public health issue. But that's just the thought of what you would do.
So, for our guys, they like Nylar, which is an IGR. So, the brand name is Archer and so that's an insect growth regulator. So, you want to spray it because you want to use an adulticide to knock the adult fleas down and then you want to use that, an IGR, because it prevents the continuation of the cycle. The larvae won't then be able to develop into a pupae. The pupae won't be able to emerge as an adult. Same thing with the permethrin though. You want to do another application at 30 days because in case you didn't get all of the adults and you didn't get all the eggs, you need to still break that cycle. So, you can't just assume that one application is going to do it. You will probably need to do two. And then the efficacy of it varies with climatic conditions. So, obviously if it's out in the blazing sun, you know the efficacy isn't going to last as long because there's going to be UV degradation. Also if it's rained, if there's a ton of wind you know the product may not stay as well or be as effective because it is a chemical, it will break down over time. Yeah?
Yeah. I just want you to clarify that. So, in either case, if you going to apply pesticide for fleas, it can't be just one application because I'm running into a pest operator that says he can do it with one application, does that sound a little that?
I mean, I would say so. Because my background is not in pest control, you know, I came from academia so I don't have a lot of firsthand experience. I'll be the first to admit it on doing flea treatments. So, I asked David, James and I asked a bunch of the other guys in our office who actually are pest control background and there used to be technicians and used to own their own companies and that this was their recommendation to be effective. That, you know, because yeah, so if you could do the one off, you know, it sounds really great, you know if you are a client. "Oh, I only have to come in once and spray," but you know, that may not actually be because if you've got eggs down in the carpeting or whatever it is that you didn't get, you know, and that product is only good for 15 days, you know, or whatever it is. Like depending on where the life cycle is in the flea, when you treat, you're not going to be able to do control for all of the state life stages before that product becomes ineffective.
Yeah, I'm going to get to that actually in a second. So, dusting of rodent burrows, we do this. Now, I don't know if you guys would be able to or not. Like I said, we do want to under a vector control exemption because if the public health risk, so actually this is a picture. So, actually right here is a shot of, we're actually baiting for control for the Norway rat. So, this is a site that I mentioned where it's like Swiss cheese. Where like the whole side is collapsing so we have no choice but to go in and try to knock the population of the rats down. But with that, so you know, you obviously want to look for the active burrows and stuff. You don't want to be putting product out in burrows that are not being used, right?
And putting out more into the environment. You can also do the same for wildlife burrows. So possums, skunks, you know, you can also dust their boroughs as well for fleas if you need to. And what we use is Drione which is a pyrethroids. So, we have found for us that it's been very effective. So actually, before I started working with Alameda County, we did have a situation at one of the homeless camps where the flea load was really high. The residents were getting bit and it was becoming a problem. So, we went out and trapped and then the guys went and did, a couple of different applications. They did two applications I believe of Drione and it knocked the flea load down to one flea per rat, post treatment. Previous to that it was six. So, it is effective if you do it properly. So, you just go in and you blow the dust into the borough and it's, it's enough that that residual where the rats are moving and the fleas are moving, that the fleas move through it and it's effective. So, it's obviously not the same as, you know, it's not that it's going to do 100% of flea control, but it'll knock it down to a level where it's no longer a public health hazard.
So, what are some other more sort of IPM things that you guys can do? So other things that you guys can do because fleas are insects, they need a certain amount of moisture in order to survive. If they dry out entirely and desiccate they'll die. So something that you guys can do too is remove the leaf litter and debris from an area where you've got a flea infestation because that opens it up to have more wind, more sun and the fleas will dry out. For burrows, you can open the burrows essentially--you know, it's a lot of manpower, but you can dig them out, dig them open, let more light and air get in there. And then hopefully the larvae and the eggs that are left in there, will desiccate. Chances are the adults will probably move off once the host is out because there's nothing for them to feed on.
But you'll stop the cycle because the larvae and the eggs that are left will dry out and die. And you can also remove the vegetation. So, if you've got a lot of undergrowth and stuff in an area, right, it's damp, right? It's very humid, it's moist there, clear it out, remove that brush from that area and then that will open that up and allow the wind to blow through it. And then the sunlight can penetrate, and it will dry out that area and hopefully knock them back if you cannot apply a product to that area.
So, just in conclusion, rickettsia felis is a newly described species of the spotted fever group. It was previously thought to be rickettsia teifi, but it's now been found to be a separate pathogen. It is transmitted to the humans by a bite of an infected arthropod in particular. It is associated and the main vector is the cat flea, Ctenocephaides felis. A number of different invertebrate vectors have been found worldwide to harbor it. But what we don't know yet is how good they are at actually transmitting them to humans and causing pathogenicity, And the worldwide distribution of felis is associated with the worldwide distribution of its host, the flea, and then also humans and pets and animals that they're feeding on. So, with that, I would like to acknowledge our former director, Lucia Wii [?] who all of this sort of disease surveillance and stuff in the county was really sort of her dream and goal and her baby. So along with her and our manager and interim chief, Bob Gay, that's how we got our new lab. And I'd like to thank my colleagues, David James, Bruce Kirkpatrick's, [Utapa Baisuais [sp] Natalia Federova, Michael Mooney, Augustine Divia, and Alex Gutierrez, who all helped and continue to help with this project. So, with that, I'll take more questions if you guys have any. Thank you. [Applause]