Bug guts shed light on Central America Chagas disease

Chagas disease is caused by the protozoan parasiteTrypanosome cruziand can cause both acute and chronic infections in humans, who most often catch the disease from the bits of infectedT. dimidiata. A better understanding is needed of the complex interactions between the human host, theT. cruziparasite, theT. dimidiatavector, and other microbes that reside in the guts of the vector.

In the new work, Sara Helms Cahan, of the University of Vermont, USA, and colleagues studied 61 adultT. dimidiatawhich had been previously collected throughout Central America from 1999 through 2013. The researchers isolated DNA from the abdomens or legs of each preserved specimen and sequenced the genetic material, which represented a mixture ofT. dimidiataDNA as well as DNA from any vertebrate blood meals and any microbes residing in the guts of the insects.

Using the DNA from theT. dimidiatalegs, the researchers assembled a reference genome for the bugs. Then, they were able to study the DNA from the guts that didn't match the vectors. They identified vertebrate blood meals including chicken, dog, duck and human, and two strains ofT. cruzi. Additionally, they found that infectedT. dimidiatahad a higher bacterial species richness in their abdomens compared to uninfected insects.

"Overall, our results show that a mixed-DNA approach can provide simultaneous information on the community of biotic factors involved inT. cruzitransmission," the researchers say. "Testing this sequencing method with different vectors and disease models will help to determine its reproducibility in other systems where multiple organisms interact in tightly-integrated and complex ways."