Category Archives: Vectors

Chagas’ Disease is NOT the new AIDS: Part I

IN SPITE OF WHAT YOU MAY HAVE READ IN MY FAVORITE NEWSPAPER (the NY Times):

It is a great picture of the bug, though. Why do biting arthropods always have their portraits taken while posing on human flesh?

Chagas’ Disease, while being a medical nightmare, is not the new AIDS.

  • The first, and perhaps biggest problem with this article is calling Chagas’ Disease the “new” anything. Chagas’ disease was discovered in 1909 by a brilliant Brazilian scientist, Carlos Chagas. Chagas’ discovery was justly recognized for this great discovery during his own lifetime.
  • Chagas’ disease is like AIDS, in that it targets certain populations, but that is where the similarity stops. Chagas’ disease is spread by a vector (bugs of the family Reduviidae) that is exquisitely evolved to infect the poor, as it is related to low-quality housing. AIDS does target the poor of the world more than the rich, but there are certain groups that AIDS targeted, or continues to target, that have nothing to do with economic standing. AIDS is not transmitted by arthropod vectors (though there was concern in the early years of the pandemic), but by sexual contact and contaminated transfusions and medical equipment. Chagas’ disease can be spread by transfusion, but this risk is decreasing. As of a few years ago,around two decades after the blood supply began being screened for HIV,  the blood supply in the US began being screened for Chagas’ disease.
  • Chagas’ disease is called a Neglected Tropical Disease. These are diseases that have high prevalence in the hotter regions of the globe, affect a large number of people but yet do not get a lot of attention from the press, their governments, NGOs, and even much of the local population. For example, many residents of Lima (where the power is) don’t even know what Chagas’ disease is, even though it afflicts a large number of Peruvians. Why?  It doesn’t occur in Lima, and public education about the disease does not extend to those who won’t get it, even though they may be the ones most able to help.
  • Stigma: Yes, it sucks to get AIDS or Chagas’ or both together. But tell me from your heart of hearts: Which would you rather tell your co-workers and parents–that you’ve contracted HIV or that you’ve contracted Chagas’. I’m betting on Chagas’. 30 years into the epidemic, and HIV/AIDS still carries a burden unmatched by any other disease.
  • Research funding: No comparison. HIV/AIDS has been a research juggernaut over much of the pandemic. As a result, we’ve made brilliant and amazing progress in treatment and prevention of the disease. Chagas’ disease is still treated by the same two lousy drugs that were used over a decade ago. Some research is being done on new treatments, but I you’d be embarrassed to see the shoestring some of those labs run on. Moreover, most of these studies involve using drugs that were already approved for other indications, such as anti-fungals and anti-malarials.(They ain’t much money to make sellin’ drugs to po’ folk in the developin’ world.)

    No mention of Chagas' disease here.

    No mention of Chagas’ disease here.

That last one was our 100th Post!

LET US GIVE THANKS TO ST. BRIGITTE, OUR PATRON SAINT

Even though this is a public health site, it seems that more people have been led here by the formerly freakishly thin-waisted,

Head, thorax, abdomen..

animal-loving,

buck-toothed,

In her defense, she did say: "Apart from my husband—who maybe will cross over one day as well—I am entirely surrounded by homos. For years, they have been my support, my friends, my adopted children, my confidants."

and proud  hate-speech spewer (several times arrested and fined)

WE KNOW that it would be mean-spirited and even provincially gringoish to disparage a great cultural icon and source of pride to the Gallic heart. We just want to give our readers more of what they want, with the ulterior motive of promoting public health.

With that in mind, we provide this link to an article on the movement to address Neglected Tropical Diseases.

Assassin Bugs on the Beach

And now, …

Did Darwin Die of Chagas’ Disease?

From The Voyage of the Beagle:

We crossed the Luxan, which is a river of considerable size, though its course towards the sea-coast is very imperfectly known: it is even doubtful whether, in passing over the plains, it is not evaporated and lost. We slept in the village of Luxan, which is a small place surrounded by gardens, and forms the most southern cultivated district in the Province of Mendoza; it is five leagues south of the capital. At night I experienced an attack (for it deserves no less a name) of the Benchuca, a species of Reduvius, the great black bug of the Pampas. It is most disgusting to feel soft wingless insects, about an inch long, crawling over one’s body. Before sucking they are quite thin, but afterwards they become round and bloated with blood, and in this state are easily crushed. One which I caught at Iquique (for they are found in Chile and Peru) was very empty. When placed on a table, and though surrounded by people, if a finger was presented, the bold insect would immediately protrude its sucker, make a charge, and if allowed, draw blood. No pain was caused by the wound. It was curious to watch its body during the act of sucking, as in less than ten minutes it changed from being as flat as a wafer to a globular form. This one feast, for which the benchuca was indebted to one of the officers, kept it fat during four whole months; but, after the first fortnight, it was quite ready to have another suck.

Why I Don’t Think Ms. Kelly is Going to Get Chagas’ Disease

I received this question from Asia Kelly the other day:

Dr. Lerner, thank you for the informative post about Chagas disease. I am a biology student at the University of Texas Pan American in the Rio Grande Valley, South Texas. Last night I believe that I saw an “assassin bug” last night outside of my home near my front door. I am a little worried because I frequently sit outside at night on my porch and I get bitten by what I assumed to be ants or mosquitoes. I’m concerned that I may have been bitten by this insect. I’m wondering if the bite from that bug would cause a rash, swelling, or any sign that it has bitten me. I’m actually very concerned. Also, TV personality Dr. Oz said in a recent show that there is no cure or treatment and that most people will die from chagas in about 20 years. I’m interested in your opinion about this and I’d like to know of any information you might know about the prevelance of this disease in my area. I looked for your email on this site, but cannot find it. Thank you so much.

Ms. Kelly:

You would have to be extremely unlucky to get Chagas’ Disease in the United States. Although Trypanosoma cruzi, the parasite responsible for Chagas’ Disease does exist within our borders, there have only been 7 autochthonous cases, meaning cases acquired here. Admittedly, at least three of those cases were in Texas, but all of those cases were infants, which points out another reason why I don’t think that you are going to get Chagas’: Assassin (kissing) bugs are big bugs, around 2 cm in length. If one gets on you or bites you, you are likely to know it. You can get bitten in your sleep, but we have to remember that it is unlikely that the bugs are in your house. Typically, they live in the cracks in the walls of mud houses, between the bricks of unplastered walls, or in the fronds or thatch that are used for roofing. Some species live outside (like the  North American species of triatomines), but these species–judging by the lack of autochthonous cases in the US–don’t seem to pose much danger.

Furthermore, remember that the infectious material is not the insect’s saliva, as it is with tick-borne or mosquito-borne diseases (like ehrlichiosis and West Nile Virus). The parasites are found in the feces of the assassin bugs. That means that if the insect doesn’t defecate while it bites you, it can’t infect. Apparently, the triatomines that we have here in the US don’t have that behavior.

So, while history has shown that it is possible to acquire Chagas’ disease in the US, it has also shown that it is extremely unlikely. Perhaps this will change, either to due to global warming, evolution, or the introduction of a competent vector–either inadvertently or intentionally–into the United States.

As far as vector -borne disease in the Rio Grande Valley go, I’d be more worried about those transmitted by mosquitoes. Dengue, for one,  has reared its ugly head along this area, and will probably do so again.

Why Hadn’t I Heard About Chagas’ Disease Previously?

How is it possible that a disease that has infected at least 10 million people, all in the Americas, has gone under the radar for so long? Chagas’ Disease was discovered just over 100 years ago, and is the most common parasitic disease in our hemisphere.

The truth is that Chagas’ Disease infects only people who are not going to influence the headlines. The vector–that is, the insect responsible for transmitting the disease–is exquisitely evolved to infect only the poor.

How can an insect probe your pocketbook?

Assassin bugs–at least the ones that have historically been the most responsible for the spread of the disease– have characteristics that cause them to pick on the impoverished.

  • They live in the cracks of the walls of houses. If the house is made of mud, it’s virtually an assassin bug housing project. Also, in many places, people  are living in the houses while they build them–each part gets completed as money is available. A brick wall that hasn’t been plastered yet is another prime hiding place for the vinchucas.
  • Assassin bugs are strictly nocturnal. Therefore, just visiting an infested house isn’t going to result in a bite–one has to sleep in one in order to get bitten. Assassin bugs can fly, but they tend not to fly much or far. So unlike malaria, which is spread by mosquitoes, an insect that is far much harder to escape, avoiding the assassin bug is rather easy.
  • Standing in front of ideal assassin bug habitat

    Lacking stucco or plaster, a brick wall is a vinchuca's paradise

Time to Shudder: Carrier of Chagas’ vs. Carrier of Rabies

What’s even scarier is that the Youtube link has Scott Brown for Senate  pop-up ads. I apologize for not being able to get rid of those. I consider Scott Brown a little below the bug on the evolutionary scale, and far more disgusting.

The Usual Suspects, Part II: Rhodnius prolixus

Another important vector of Chagas’ Disease

Rhodnius prolixus

Back to Business: Assassin Numero Uno, Triatoma infestans

Triatoma infestans, the most common assassin bug vector in the "Southern Cone"