- Kissing bugs (scientifically Triatoma bugs, also called conenose bugs) are an outdoor insect found throughout Texas. They feed on the blood of wildlife, especially rodents. Recent studies of wild-collected bugs from across the state have found that about half of collected bugs are infected with a parasite called Trypanosoma cruzi. This parasite causes a relatively little known disease called Chagas disease.
- Chagas disease is insidious in that people often don’t realize that they have been infected. After an initial acute phase that resembles the flu, it can lurk in the body for 20-30 years before causing symptoms. For about 30% of those who become infected it is potentially fatal, causing premature death from cardiac or intestinal complications. Undoubtedly some people who die from heart failure might trace the cause back to an earlier Chagas disease infection. There is no cure for later stage Chagas disease, though there are some experimental therapies for early stage infections. http://kissingbug.tamu.edu/FAQ/
- Blood banks now test for the disease when blood donations are taken; but typically they only test the first time you give blood. This leaves open the possibility that anyone who becomes infected after already giving blood are not detected, and means there is a risk of infective blood getting into the blood bank system. Blood banks argue that the risk is very low, others disagree.
- In recent years it’s become evident that Chagas disease is very common among Texas canines, especially in the southern Texas counties. Dogs will eat the kissing bugs, and acquire the pathogen more often this way.
- More people in Texas are being infected with Chagas disease than previously recognized. Over the past 50-60 years there were thought to be only 5 cases of locally (US) acquired Chagas disease in Texas. Recently, however, Chagas became a reportable disease for doctors, and more aggressive testing over the past two years has showed at least 12 locally acquired cases occurred in Texas between 2013 and 2014. An estimated 300,000 people in the US carry the pathogen; but most of these infections were acquired out of the country in Mexico, Central or South America where the disease is much more common.
THE REST OF THE STORY
Not mentioned in the news stories is that there is a reason that Chagas is much less common in the U.S. compared to Latin America. For reasons that are not fully agreed-upon, human transmission is not nearly as high in the U.S. The most likely reason is that we have different species of Triatoma bugs acting as vectors of the pathogen here. Some have speculated that differences in vector infection rates is related to the fact that Trypanosoma infections occur not through the bug mouthparts (like mosquito transmitted viruses), but via their feces. Feces deposited near a bite must subsequently be rubbed into the wound to cause infection. It could be that our US species have a slightly different biting or defecation behavior, reducing the risk of bug feces being rubbed into the wound.
You may notice that health officials interviewed in the TV reports seem to downplay the significance of Chagas in Texas. The reason is that there is not enough data to verify that Chagas is a common problem in Texas. Health professionals rightly don’t want to worry folks until more is known about the extent of the problem. Yes, dog infection rates are very high where the bugs are common; but researchers think this is because dogs acquire the pathogen orally, when they eat bugs. It does not mean that people are at equal risk in areas where the bugs are common.
TV reports also fail to distinguish the difference in risk of acquiring Chagas in north Texas compared to other areas. Highest risks for both dogs and people appear to occur in southern parts of the state. Dr. Sarah Hamer of the Center for Veterinary Medicine at Texas A&M, along with researchers with the military, Baylor University, and the Department of State Health Services are actively studying Chagas disease, and statewide distributions of the different species of kissing bugs—essential information for health officials. We will undoubtedly know more about this problem within the next few years.
RESPONDING TO THE PUBLIC
You can expect to receive calls about kissing bugs from the public as local TV stations and newspapers pick up the Dallas reporting. If you receive inquiries about these bugs, the first thing is to make sure the client really has a kissing bug. The chance of encountering kissing bugs outside right now is relatively low. Kissing bugs are not seen very often by the general public because they come out at night. Additionally, they are warm season insects and will not be very active now because of the cold weather.
Even when the season is right, there are several bugs that people commonly mistake for kissing bugs. In fact, the labs that handle kissing bug samples are overwhelmed right now with these non-kissing bugs as a result of the recent news stories. For these reasons I just posted a guide to kissing bug ID at http://citybugs.tamu.edu/2015/12/01/kissing-bug-identification-requires-closer-look/
If after studying the descriptions and pictures, if you or your client still think you have a kissing bug sample, there are two labs that are interested in testing these insects. If the bug is not known to have bitten any one, then go to this Texas A&M Center for Veterinary Medicine Kissing Bugs and Chagas Disease website. http://kissingbug.tamu.edu/contact/ The online contact form should be filled out and (preferably) a photo of the specimen submitted, then the A&M team will respond via email with information on how to send in a bug for testing.
If the bug is known to have bitten a pet or person, it should be sent to DSHS according to instructions at http://www.dshs.state.tx.us/idcu/health/zoonosis/Triatominae/
FOR MORE INFORMATION
For more general information about kissing bugs, see my fact sheet at http://citybugs.tamu.edu/factsheets/biting-stinging/others/ent-3008/ And, Dr. Sonja Swiger is recording a nEXT conversation about kissing bugs and Chagas disease on Dec 3. The session should be available shortly on http://Agrilife.org/next
Please let me or Dr. Swiger know if you have any further questions.
Michael E. Merchant, PhD, BCE
Professor and Extension Urban Entomologist
Texas A&M AgriLife Extension Service
17360 Coit Rd | Dallas, TX 75252-6599
972-952-9204 | firstname.lastname@example.org
Blog for professionals: http://insectsinthecity.blogspot.com
Follow me on Twitter: @mikemerchant