Triatomic beetles and their trypanosomes are popping up in New Orleans, a popular mecca for food, art, and music – reminding us that parasites and their vectors don’t play by our rules.
Types of kiss bugs found in the United States. Curtis-Robles et al., CC BY 4.0 via Wikimedia Commons
The World Health Organization and Centers for Disease Control recently announced that SARS-COV2 is transmitted through aerosol droplets. We’ve known this critical little tidbit for over a year, but is this explanation finally coming true?
In many ways the answer is yes. When something is OFFICIALLY ANNOUNCED, resources begin to pour in to resolve the OFFICIAL PROBLEM. Of course, less so with COVID-19, as it has developed into a bonified pandemic. But for many other diseases this is a real problem. Chagas disease, for example. Last month we celebrated a day designated by the World Health Organization to raise awareness of this widespread parasitic disease that affects millions of people in almost every country in the Western Hemisphere.
Although millions of people have Chagas Disease, a lifelong parasitic infection that can lead to heart failure, the disease is unknown in the US as it is NOT officially TRANSFERRED HERE. Despite 112 years of research into the disease, there is no vaccine (and certainly no Operation Warp Speed for a disease that is NOT HERE). The parasite that causes Chagas disease Trypanosoma cruzi, is transmitted in a number of ways, including contact with triatomic bug droppings. Like HIV, measles, and likely COVID-19, Chagas disease is a zoonosis, which means we share it with animals.
Zoonotic diseases can jump from animals to humans and back again; they are a symbol of the interwoven nature of planetary and human health and a symptom of the ongoing destruction of non-human habitats. Chagas disease is particularly complex because it is caused by a parasite, spread by a beetle, and housed by mammals, including us. As a result, the disease spreads within and between many different landscapes – forests, villages, and everything in between.
There are many assumptions about where T. cruzi Transmission happens and by what. Most of these assumptions are based on the lack of evidence, starting with Chagas disease being a rural poverty disease. While Chagas disease is transmitted in rural areas, it can also be spread in urban areas. T. cruzi– Infected kiss bugs have been found in cities across Latin America – Sao Paulo, Rio de Janeiro, Cochabamba, Arequipa, Caracas – and the list continues to grow.
The second assumption is that bug kissing is a “south of the border” problem. Studies of triatomics in the United States are on the rise, and it’s not because the beetles here hitchhiked with Central American immigrants, regardless of what some news outlets would like to tell you. The beetles have been here for millions of years. The thing is, people have only just begun to be interested in what entails a third Chagas principle, although it is generally true – if you look for triatomines, you will find them. Kissing bugs in the US started drawing a lot of attention in 2009 when bomb detection dogs stationed in Iraq began showing cardiac symptoms due to T. cruzi Infection. With Chagas disease spread only in America, attention shifted to where the dogs were being trained – San Antonio, Texas. Of course, the US government pelted the problem with tons of money. A series of follow-up studies found that four types of kiss bugs live in and around Texas military kennels, and dogs infected with them T. cruzi were found all over Texas. A number of new studies on kiss bugs followed and are still taking place. As recently as this year, a study of 476 state working dogs in 40 US states found: T. cruzi Seroprevalence of 12.2% (58/476). These studies also show that kiss bugs are common in human-dominated areas (not just “natural areas”) of Texas and the greater United States. Ironically, 2009 was 100the Anniversary of the discovery of T. cruzi by Carlos Chagas in Minas Gerais, Brazil. I can’t help but wonder what all that money thrown Chagas in military babies could have done for the millions of people who suffer from Chagas Disease in Latin America and the Caribbean.
But we’re not here to talk about US military spending, and we’re not here to talk about Texas. We’re here to talk about N’awlins, the city of jumblaya, jazz and … kisses? In a city that tourists flock to to enjoy its unique food, arts, and cultural scenes, it’s especially fascinating that recent studies reveal that kissing bugs and T. crossInfected mammals want to be there too. In their recently published paper in Parasites and Vectors, Ghersi et al. found 11% of the rodents positive for T. cruziincluding those from tourist hotspots like the French Quarter. And just a few weeks earlier, Dumonteil et al. reported that 25% of the cats from the shelter examined in southern Louisiana were positive to T. cruzi. In another study, 45 beetles collected from human houses and animal shelters were molecularly analyzed to determine the hosts the beetles ate from and found that the beetles opportunistically feed on a variety of species, including birds , Reptiles, amphibians, and mammals, both domestic and synanthropic. Finally, another study from 195 sequences found out Triatoma sanguisuga collected in and around human residences in Orleans Parish (ie county), human blood meals were found in 162 of them.
Most importantly, the beetle’s predominant host species were humans and their animals. This finding makes me think that yet another Chagas dogma is being turned on its head, namely this vector-borne dogma T. cruzi Transmission in the US is strictly enzootic. I anticipate that greater access to molecular tools that enable the identification of numerous blood meal host species, coupled with more people searching for the bedbugs, will turn these Chagas transmission dogmas into evidence-based acceptance that the T. cruzi is transmitted to humans by kissing beetles in several landscapes, including urban areas, in the United States. No, it’s not that common and no, there is no need to freak out. But as I wrote earlier, these dogmas and terms of “this happens here, but not here” and “for them, but not for us” are not helpful. These labels serve as barriers to access to resources and to raise awareness for those who need to be careful (medical professionals, people who live in areas with the beetles). We, as a global health community, need to stop slapping those labels and categorizing them as “forever” and start accepting that the transmission will take place where it takes place. Perhaps then we will learn to be frivolous and perhaps to react in good time at some point.