To spread from an infected person, Dengue viruses circulating in their bloodstream need to be picked up by a mosquito that bites them to take a blood meal. In a mosquito-borne disease like, the proposition to a Dengue-infected person with to minimize their chances of spreading the infection to others then makes sense. Question is whether this is feasible. Dengue presents a two-fold problem in this respect (see figure below from Dengue: Guidelines For Diagnosis, Treatment, Prevention and Control Guidelines for Diagnosis, WHO, 2009, page 25. )
- One, Dengue’s clinical symptoms start with acute-onset fever and in that respect it resembles too many other illnesses.
- Two, Dengue viremia, i.e., viruses circulating in the bloodstream, also occurs precisely during this phase.
In other words, Dengue viruses circulate in the bloodstream and are available to be picked up by a biting mosquito taking its blood meal precisely when there is no specific indication to suggest the person’s ailment is indeed Dengue.
Given how Dengue-induced fever and viremia coincide in time, we could even speculate Dengue virus infection of humans is exquisitely adapted to maximize its potential to spread. The window of opportunity to isolate a Dengue patient at the right time being extremely narrow, perhaps even non-existent, renders the likelihood of being able to do so vanishingly small.