I caught a Vinchuca!

Mid-dissection from Lulu
This one has not had a recent
blood meal, seen on intestines

So Chagas disease is caused by a parasite, Trypanasoma cruzi, which is transmitted by a bug.  The bug is called reduviid (scientific name), "kissing bug" (fun name for unclear reasons), or vinchuca (local name here).  The bug lives in the wild and bites animals, but it also lives in houses that are very poorly constructed, ie of mud/dirt.  It hides in the the earthy holes (see pictures), and the bugs come out at night to feed on people when they are sleeping.  Which, now that I have seen the size of these things, is terrifying.  They seem to have the same size range and crunchiness (I imagine with their hard shell) as cockroaches.  

The parasite circulates in the blood stream like malaria, and similarly is picked up when the bug takes a blood meal.  Unlike malaria (transmitted by the saliva), the parasite is transmitted through the bugs feces.  Thus, transmission only occurs when a person scratches at a bite with feces nearby, brushing the parasite into the skin.  So transmission of the disease is about 1 per 1000 bites, but these things used to be all over houses.  One patient said he could kill 50 bugs/night with a pin when he was a chile, and starting about the 1950s they learned that the vinchuca transmitted Chagas so fumigation schedules/ campaigns for better housing began.

Anyways, per patient reports Santa Cruz hasn't had vinchucas in the city for about 30-40 years.  Other smaller cities have also changed their housing structures.  However farther outside the city in the farmland (the campos), there still exists this mud housing where vinchucas can live.  So we went vinchuca hunting... 

The first couple days the girls went to houses that had (fortunately) just been fumigated, so no vinchucas.  However, I came for day 3 to a house even further outside the hospital post, and look what we found...

this is the kitchen, where the vinchucas live

we rolled up in an ambulance.  on the way back I sat in
the front and greeted everyone with fun noises it makes

the living quarters of the house.
vinchucas (likely from the neighboring kitchen)
were seen at night in some larger cracks

The process:  spray with bug spray to irritate the bugs, but
not enough to exterminate them (Lulu needed the bug and
parasite as alive as possible to try and extract DNA for analysis)
Catch them by the legs with tweezers!  Pick up any small eggs,
which don't have T. cruzi but would likely soon pick it up from
the livestock and others in the house

Toria and Malasa- the Camiri project heads
Thanks so much for all the organization!

the way out to the communities.  they are 2 hours outside
Camiri, which is four hours outside Santa Cruz.

Ew!  We found their exoskeletons all over the house, too
We ended up catching 15 and collecting many eggs to start a
new lab colony.  There must be hundreds of vinchucas living in
the housing, and the house is scheduled for fumigation soon.
Likely that everyone already has Chagas, but there are small
kids, and also a theory of "superinfection" where infection
with more strains produces worse disease.

Lulu!  The inspiration for all of this.
PhD candidate from London School of
Tropical Medicine.  This chica is a T. cruzi
expert, who is dating a T. brucei
(African Sleeping Sickness) expert!

Ducks.  The previous survey group in
the area found them to be associated with
increased Chagas transmission.  Many
animals are also hosts (they get bit by the
blood-thirsty vinchucas too).  The number one
spreader of sylvatic (wild) Chagas to
humans is... armadillos!

the lovely vinchicas!  family pic : )
back: Nicole, Malasa, Toria, me.  front: Lulu, Jillian

thanks Nicole for this great photo!