Elliot had caught dengue in Vietnam and during his weeks of delirium had felt vaguely as though he were floating in rubber.
Since he arrived in 2003 Carroll has faced down fraudsters, totaled his truck twice, been raided by the police and caught dengue fever.
He and his colleagues are also examining whether any of the insects they caught were infected with dengue, chikungunya, or other viruses.
The phenomenon is called antibody-dependent enhancement (ADE), and it helps explain why more severe cases of dengue including a very dangerous condition called dengue hemorrhagic fever tend to happen when a patient catches a second type of dengue.
'In my house alone, both my mother and brother have dengue, and it's the second time my brother has caught it.'.
"In my house alone, both my mother and brother have dengue, and it's the second time my brother has caught it," Leonardo Almeida Oliveira, a 20-year-old student from Embu das Artes in São Paulo, told VICE News.
"Elementary students who are very little will catch a mosquito and ask me if that mosquito is the one that transmits dengue or not.
Aedes aegypti was the predominant mosquito caught in the trap and some (5.73%) were found to be positive for dengue virus.
There were a lot of fevers like chickungunya and the dengue fever and also other new fevers that were contagious; so that when one family member caught it, they all caught it.
