Some ticks carry more than one disease

[00:00:00] Host Amber Smith: Upstate Medical University in Syracuse, New York invites you to be "The Informed Patient" with the podcast that features experts from Central New York's only academic medical center. I'm your host, Amber Smith. Dr. Saravanan Thangamani's tick surveillance program at Upstate has tested more than 27,000 ticks since it began in 2019, and about a third of those ticks have been found to carry a pathogen or pathogens. Recently, some ticks have been found to carry up to four pathogens. Here to help us understand what this means is microbiology and immunology professor Saravanan Thangamani. Welcome back to "The Informed Patient," Dr. Thangamani.

[00:00:42] Saravanan Thangamani, PhD: Thanks for having me.

[00:00:43] Host Amber Smith: We've spoken before about your lab and the community-engaged tick surveillance you're doing. Does the fact that three or four years into this project you've now come across ticks carrying multiple pathogens mean anything?

[00:00:56] Saravanan Thangamani, PhD: Yes, of course. There are two things that I'm trying to highlight from our program is that the number of ticks that we receive in the lab are increasing. In addition to that, the number of pathogens that we detect within the tick is also increasing, which means the rate of prevalence is also increasing. So on one hand, number of ticks are increasing. The other hand, number of pathogens in the ticks are also increasing.

[00:01:22] Host Amber Smith: Are you still, is it about a third that have at least a pathogen?

[00:01:26] Saravanan Thangamani, PhD: Yes, it hovers around between 33 and 37%. Again, we are normalizing throughout the state of New York, but if I bring it down to this county level or ZIP code level, the numbers vary from each other. So there are some counties that go all the way up to 60% of prevalence of pathogen in the tick, versus other counties that are 33%. So it varies, but if we can average it throughout New York state, yes, it's one third of the ticks carry at least one disease causing agent to humans.

[00:02:01] Host Amber Smith: Now across New York state, which is the most prevalent pathogen that you find?

[00:02:06] Saravanan Thangamani, PhD: The Lyme disease causing agent is still the most prevalent pathogen that we are detecting in the ticks.

[00:02:12] Host Amber Smith: And when you talk about co-infections, or ticks that carry more than one pathogen, is there a geographic area where that happens more than not?

[00:02:23] Saravanan Thangamani, PhD: So I must tell that 18% of the infected ticks are co-infected with at least two pathogen, right? And then 3% of the infected ticks actually carry three pathogens. So if I can break it down, the ticks that are coinfected with the Borrelia burgdorferi, the Lyme disease agent, and Babesia microti, the agent of babesiosis, they are actually prevalent in Central New York and Lower Hudson Valley. The same goes for the ticks that are co-infected with the Lyme disease agent and the anaplasmosis-causing agent. That is all in the Central New York and Lower Hudson Valley. However, the ticks that are co-infected with the Powassan virus are all centered in the lower Hudson Valley. So we are starting to see a geographic separation of these co-infected ticks as well.

[00:03:15] Host Amber Smith: Is it pure coincidence for one tick to become infected with multiple pathogens when the tick next door is infected with none?

[00:03:26] Saravanan Thangamani, PhD: I wouldn't say pure coincidence. It is a matter of these ticks that actually feed on wildlife. If the particular wildlife, like a mouse or a squirrel or a groundhog, if they carry multiple pathogens, when the ticks feed on them, they also acquire those pathogens from the mammal. But you have to understand that ticks feed on mammals at different stages. Like when they are lare, they feed on a host. Let's say for example, if that host is a mice that has a Borrelia burgdorferi, the Lyme disease agent, the larvae now will acquire this Borrelia, and they, when they become nymph tick, they already have the Borrelia in them. And then if that nymph tick feed on another mammal that has babesia, then it'll take the second pathogen. So it has more opportunity to acquire additional pathogen throughout its lifecycle. And that is, unfortunately, the biology of the tick because it encounters a mammal for blood feeding every single stage. In addition to that, we know from our own research that mammals in the wildlife can carry multiple pathogens, which means that a single tick can feed on them, acquire multiple pathogens.

[00:04:34] Host Amber Smith: And do they transmit the pathogens to humans the same way they would another animal if they were feeding on, I mean, we're all mammals, right?

[00:04:43] Saravanan Thangamani, PhD: Exactly. They would transmit the same way as they would transmit a singly-infected tick, as well. In fact, when the ticks are coinfected, it alters the tick behavior in such a way that it'll probably make the tick a little bit more aggressive feeder, as well. So we have found that in our own lab that Powassan virus infected ticks, together with Borrelia burgdorferi, it alters its behavior, and it actually injects more virus to the mammal. So it actually can exacerbate the clinical outcome as well.

[00:05:16] Host Amber Smith: That's a little frightening. Now, Central New Yorkers are generally familiar with the bacteria that causes Lyme disease. I'd like to have you tell us about the other three pathogens that you found together. Let's start with the one that's a bacteria.

[00:05:30] Saravanan Thangamani, PhD: So the most common one that we find together with the Lyme disease agent, is the anaplasma phagocytophilum bacteria that causes anaplasmosis. The initial symptoms for this particular disease are mostly non-specific acute febrile illness, such as fever, chills, severe headache and myalgia. And rash is uncommon with anaplasmosis, but it has been reported in less than 10% of the cases. The case fatality rate for patients who seek care for the illness is almost 1%. But in an immunosuppressed individual, this number can go higher as well.

[00:06:09] Saravanan Thangamani, PhD: The second most dominant in co-infection we see in the ticks that we receive is the Babesia microti, which is a causative agent of babesiosis. And again, babesiosis, the common symptoms are non-specific flu-like illness, such as fever, chills, headache, body ache, loss of appetite. But I must tell that Babesia microti is closely related to malaria parasite. So it is a protozoan. It is a parasite, and it's not a bacteria. It's very similar to the malaria parasite. And it can cause anemia in human humans as well. But this one has a high case fatality rate. It's up to 5% case fatality rate.

[00:06:56] Saravanan Thangamani, PhD: The third one that we encounter with the coinfected ticks, or the Borrellia co-infected ticks are the Powassan virus. The Powassan virus is a neuroinvasive virus. If a human gets infected with this virus, the virus eventually ends up in the brain, causing meningitis or meningitis, or meningo-encephalitis. The case fatality rate for Powassan enchephalitis is very high. It's between 10% to 15%. In the worst case situation, 50% of the survivors who got infection but recover will have long-term neurological sequela. So these are the three primary pathogens that we observe together with the Lyme disease agent intakes.

[00:07:37] Host Amber Smith: This is Upstate's "The Informed Patient" podcast. I'm your host, Amber Smith, and I'm talking with Dr. Saravanan Thangamani. He's a professor of microbiology and immunology at Upstate, and we've been talking about tick co-infection. And before we get back to the interview, I'd like to let listeners know they can learn more about tick-borne disease research at NYticks -- that's N Y T I C K S -- .org

[00:08:03] Host Amber Smith: Now you just told us about a bacteria, a virus, and a parasite that are co-infected along with the bacteria that causes Lyme disease in certain ticks. How do those three pathogens get along together?

[00:08:19] Saravanan Thangamani, PhD: So that is a very interesting question. That is one of the subject of research in our lab to see how the co-infection alters the clinical outcomein humans. Obviously these three pathogens, when they're in the tick, they compete for the same resources. And obviously, what happens is that it alters the tick behavior in one way or the other. It will actually cause severe disease in humans. That will actually add more complications for the treatment. Because instead of treating one single agent, now you have to treat for multiple agents.

[00:08:52] Saravanan Thangamani, PhD: For anaplasmosis and babesiosis, treatments are available, as long as it is diagnosed during the acute phase of infection. If it's not diagnosed during the acute phase of infection, it could be lethal. When it comes to the virus, there is no specific treatment. Supportive therapy is the only option at this time we have. And obviously for the Lyme disease, there are treatments available as long as it's diagnosed at the early stage as well. Definitely having more than one pathogen in a tick that bit a human or that bites humans, it only complicates the disease outcome.

[00:09:28] Host Amber Smith: So if a person is bitten by one of these ticks that is coinfected, is it guaranteed that that person's going to contract all four of those pathogens, or not?

[00:09:39] Saravanan Thangamani, PhD: It depends on how long the tick has been feeding on the human. Viruses are transmitted immediately, as soon as tick attaches to a human. Viruses are transmitted at the skin. The others -- the bacteria and the parasite, including the Lyme disease agent -- they take anywhere from 12 hours to 48 hours to transmit to the human. So if the tick is found and removed right away, you have less chance of acquiring the pathogen,acquiring the disease - causing agent. So it depends on how long the tick is attached on the human.

[00:10:14] Host Amber Smith: So prevention is still really important here.

[00:10:17] Saravanan Thangamani, PhD: Exactly. And I know that in many human cases that I know personally people who actually contracted three -- Lyme disease, anaplasma and babesiosis -- from a single bite. So it is possible that if the tick attached on a human for a good amount of time, they can contract all three diseases as well.

[00:10:38] Host Amber Smith: Do you know, do all of these get transmitted to dogs as well, potentially?

[00:10:44] Saravanan Thangamani, PhD: Yes of course. When ticks are infected, they transmit the agents to any mammal that they actually feed on. So they will be transmitting to dogs, cats, and any other mammal that they encounter.

[00:10:57] Host Amber Smith: Well, before we wrap up, I want to ask you about this past spring, summer, fall season. What has it been like for ticks in Central New York?

[00:11:06] Saravanan Thangamani, PhD: So we've been doing this tick surveillance since 2019, and what we are observing is that over the period we are seeing an increase in the number of ticks, from 10 to 15%. So if I can compare last fall to this fall, like 2021 fall versus 2022 fall, we are almost at the tail end of the season, so I can compare it. We have actually received 20% more ticks in the same fall period. So definitely the number of ticks are increasing.

[00:11:34] Saravanan Thangamani, PhD: In addition to that, the geographic expansion is also happening. We are more focused on one tick at this time. For this conversation, we are focusing on deer ticks. However, there are a couple of other ticks of importance are also emerging. Geographically, they are expanding. Like dog ticks we traditionally found earlier in the lower Hudson Valley. Now they're actually found everywhere, in Central New York, Western New York, and also North Country. The other most important tick is slowly trying to make its inroads into the Central New York is the Lone Star tick, or Amblyomma americanum tick. It used to be primarily found in Long Island and Suffolk counties, but now we are seeing more in Central New York as well, which means that in addition to deer ticks, we do have to worry about the other two important ticks that are emerging in Central New York.

[00:12:26] Host Amber Smith: It seems like we had such a warm fall. Is that part of why we're having more ticks? Are they, is it a more hospitable environment?

[00:12:35] Saravanan Thangamani, PhD: Yes. There is a direct correlation between warm weather and increasing human tick encounters. Because when the weather is warm, we spend more time outside doing outdoor activities, trekking and walking in the woods. And ticks are always there. When it is warm they try to stay at the tip of the grass waiting for some human to walk by, and they latch onto them. They go into hibernation only when the temperature goes below, I would say, 35 degrees Fahrenheit. They start to kind of slow down their metabolism. They try to kind of find nice, cozy places right under the leaf litter or debris so that they prepare itself for the harsh winter. And that's how they survive during the harsh winter.

[00:13:16] Saravanan Thangamani, PhD: I must tell here that even in winter, people encounter ticks. So through our program, we have received ticks even in January and February. You'll be surprised. Because people, they do snowshoe walking. They trek. They do hunting sometimes in the winter. And they put themselves at risk of tick exposure, as well.

[00:13:35] Host Amber Smith: But aren't people more bundled up so that their skin is covered, if they're out in the wintertime? How would ticks get to them?

[00:13:43] Host Amber Smith: They start to crawl on the winter clothing first. And then they find a way to go around the head, or when you have a wool or cotton hat, these ticks can attach to them and they can try to squeeze themselves into the threads. And then they wait. When you go home and you try to take your hat and put it on your basket, and then it comes out and start to find for somebody else in the home. We don't know how we are carrying, actually. There are many ways how the ticks, they don't have to attach right away. They can actually wait for you even inside the home. They can wait for you and then just wait for the right person to come by.... How long can a tick last without being fed? If a tick got in your house, and it was just sitting on a counter, how long could it live before it had to eat something?

[00:14:26] Saravanan Thangamani, PhD: I would say at least couple of years.

[00:14:28] Host Amber Smith: A couple of years?

[00:14:30] Saravanan Thangamani, PhD: Yes. So as long as there is good humidity there. In the winter we heat our homes, right? So it's a little bit dry environment, and that is not good for the ticks. But in summer, we air condition our homes. We give enough moisture and humidity inside the home, so they can live. But ticks are very clever. They will always find a corner where it's not too dry. Obviously they will try to go away from the dry to a moisture area, like in the bathrooms. They will find ways to survive there all the time. Doesn't matter if it's winter or summer because, you know, we use water all the time, which means that is good enough for the ticks. Ticks can be, ticks can go for a couple of years without taking a blood meal. They are very hardy.

[00:15:15] Saravanan Thangamani, PhD: So ticks doesn't die during the winter. They are very clever to find warm places for them to hide and wait until the spring warm weather comes up. They start to come out and try to find a human to feed on.

[00:15:30] Host Amber Smith: So all of these ticks from the fall, the ones that are young, or babies, they're wintering over and they're going to be waiting for us in the spring?

[00:15:39] Saravanan Thangamani, PhD: Yes. So if they take a blood meal in the fall, they moult, they become the next stage and they wait for us in the spring.

[00:15:46] Host Amber Smith: Great.

[00:15:47] Saravanan Thangamani, PhD: So the more ticks we have now means that there will be more ticks in the spring as well. So we saw 20% more ticks in the fall, which means that I'm now projecting that in the spring we will see almost at least 20% increase in the number of human encounter ticks in the lab. And again, we are only focused on what we receive in the lab. So the caveat is that can we actually project this to the entire state in a even distribution way? I cannot tell that because unfortunately, whoever is encountering the tick and whoever is aware of our program, they actually send the tick to us. So, although we try to disseminate our tick testing information throughout the state of New York. So there is a little bit of biases there, so we are trying to address that. But that's a general trend is there, that we will get definitely more takes this 2023 spring.

[00:16:41] Host Amber Smith: Well, Dr. Thangamani, thank you so much for giving us this update. I appreciate your time.

[00:16:46] Saravanan Thangamani, PhD: Thank you very much for having me.

[00:16:48] Host Amber Smith: My guest has been Dr. Saravanan Thangamani. He's a professor of microbiology and immunology at Upstate, and you can learn more about his research on tickborne diseases at NYticks -- that's N Y T I C K S -- .org. "The Informed Patient" is a podcast covering health, science and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe. Find our archive of previous episodes at Upstate.edu/Informed. This is your host, Amber Smith, thanking you for listening.