Monthly Archives: January 2010

Can you get Chagas’ Disease from another person?

Not really. Don’t get caught up in the technicalities, but remember the infective stage of the parasite, Trypanosoma cruzi, is something called a trypomastigote. It exists in the feces of the assassin bug, but also circulates in the periodically in the blood of an infected person.

You can get Chagas’ Disease from an blood transfusion, from an organ transplant, from ingesting the parasite (there have been several large food-borne outbreaks of Chagas’ in South America, with rather grave consequences) and mothers can pass it on to their fetuses.

The blood supply in the United States is screened, though, so your chances of getting it that way are virtually nil.

The research team is in Lima now, preparing to go to Colan tomorrow to check on the status of dogs there.

If they have disease, does it mean that humans are diseased?

Stay tuned.

For some reason, Brigitte Bardot has become more popular than parasitic disease

I noticed an odd uptick (do upticks carry disease?) in the number of visitors to my blog. Fortunately, there is software that tells us how HTMLyou found us.

It turns out the “Dishes from the Sixties” ploy has worked, alas a bit too well. Most of the visitors to the blog are now coming to look for Ms. Bardot, and I wonder how many of them stick around to look at the nasty little pictures of bugs. Precious few, I imagine.Amazingly, no one seems to have come here to look at Sophia Loren, who (IMHO) is far more worth the search.

So listen you naughty voyeurs! I have devised a manner in which you can avoid the eternal fires of hell and damnation (you may still end up in purgatory, but there’s only so  much pull an agnostic a with blog can manage). You must commit yourselves to reading all the posts about diseases and public health!

Your reward is more of this:

Victoria can keep her damn secret

And less of this (Anita Ekberg today–and don’t think that you’re immune):

It all got washed away in the Trevi Fountain

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

Some Real Peruvian Dogs

From my last trip. This is in and around Arequipa, the second largest city in Peru. There is a lot of Chagas’ Disease in the villages surrounding Arequipa.

There is both beauty and hard times in this area. Somehow the beginning of the Goldberg  (Gould’s version) just seemed to go with it.

One Week Until Peru!

The American Deer Tick, vector of Lyme Disease

Our research staff is heading to Peru next week.
There will be some Chagas’ research, but the main focus of this trip will be determining the prevalence of the vector-borne disease known as ehrlichiosis.
Unlike Chagas’ disease, infection with ehrlichia is spread by an arthropod that is well-known to Americans as the tick. Likewise, ehrlichia (which isn’t really one disease, but three–more on this later) is also present in the US. Here is the most up-to-date graph I could find on the web:

Annual cases of Ehrlichia in the US

A friend has said that there are too many ugly bug pictures on this blog. For her, I present this picture of Peru:

Somewhere over the rainbow, bugs may be hiding

Updated: What’s Another 2 Million (or 3 or 4 or 5 Million) People Sick?

There is more uncertainty in the total number of Chagas’ cases  than there are total cases of HIV infection in Latin America.

I picked up the just-off-the-(virutal)press issue of the American Journal of Tropical Medicine and Hygiene, the publication of the American Society of Tropical Medicine and Hygiene. There were three new articles on Chagas’ Disease. So in the same issue I read that 18 million or 9.8-11 million  or 9-13 million individuals are infected with Trypanosoma cruzi. One paper–the World Health Organization’s 2002 report, Control of Chagas’ Disease: Second Report of the WHO Expert Committee–claims that Chagas’ Disease is the main cause of death in endemic areas.

So what is the point here? Certainly not to compare one disease to another. Not all of those infected with Trypanosoma cruzi will go on to develop the debilitating and fatal chronic form of the disease, but presumably every case of HIV will infection will progress to AIDS, or require years, if not decades, of  treatment. Interestingly, there are more and better drugs for the treatment of HIV infection than there are for chronic Chagas’ Disease. To complicate matters,  immune suppression, like that caused by HIV infection, is a factor in the activation of chronic Chagas’ Disease, and there are an unknown number of cases of co-infection with Chagas’ Disease and HIV. Chagas’ Disease runs a more severe course in those who  are immune-suppressed.

So what is the point here?

It is that Chagas’ is so widespread that just the level of error in our estimates is even greater than our best estimates for the total prevalence of HIV in the same geographic area.

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.

While You’re Waiting for the Next Post…

Have another dish from the ’60s.

It's the hat.

A Chagas’ Disease Primer: Part 5

If you wish to read the Chagas’ Disease primer in order, click here to go to Part 1 and follow the links.

Acute Chagas’ Disease? What are the chances?

If a person gets bit by an infected chirimacha or vinchuca (the Peruvian and Argentine words for the assassin bug, respectively, is it likely that acute illness will ensue? What percentage of persons bit will get the symptoms that the previous primer post elaborated?

Fortunately, very few will get sick, perhaps less than 5%.These people won’t get the flu-like illness, nor will they get the chagoma. Life will go on as if nothing had ever happened.

Which is good, right?  After all, current estimates (we’ll talk more about these estimates later)  put the number of those at risk for getting assassin bug bites at around 100 million.

As it turns out, it might be better to know that you’ve been bitten. While feeling kind of punk for a few weeks would really stink, it would be good to get some kind of sign that the little parasites were working their way through your system. As it turns out, acute Chagas’ Disease isn’t the problem. It’s the chronic form that shows up 20-30 years later, when it’s too late to do much about it.  30% of those infected will get the chronic form, which could be anywhere (once again, those wildly-ranging estimates) from 8 million to upwards of 12 million people in Latin America.

The Usual Suspects, Part II: Rhodnius prolixus

Another important vector of Chagas’ Disease

Rhodnius prolixus