Yellow fever, visceral leishmaniasis, etc.: where is the medical entomology?

By Carlos Brisola Marcondes – Full professor the Department of Microbiology, Immunology and Parasitology at the Federal University of Santa Catarina

How many deaths in east Minas Gerais State could have been avoided if there was quality surveillance?

Many new diseases arose in Brazil lately, as Chikungunya and Zika, and old diseases, as visceral leishmaniasis and yellow fever in surprising places as Porto Alegre and east Minas Gerais, respectively.

New measures are needed to understand and solve these issues, which include assessing the pathogenic agents vector distribution and incidence. In order to achieve this, at least, there must be qualified personnel for several areas, and here I stress medical entomology.

For instance, it is known that yellow fever occurs in Brazil for many years solely by wild transmission, what seems to involve especially Haemagogus and Sabethes mosquitoes. The reservoirs seem to be primates, rarely finding infection among other animals, but there are solid evidences that the virus is kept in the mosquitos by vertical transmission (Carrington & Auguste, 2013). Generally, when howler monkeys die, the population close to the death site is vaccinated as fast as possible. Flaws and delays have happened, leading to deaths that could have been avoided if the diseases epidemiology were truly understood, and not merely glimpsed, as in Platos myth of the cave.

In order to understand this diseases epidemiology, it would be necessary to acquire deeper knowledge about the main vectors, related to hollow trees. How much of its biology is really known in Brazil, of its relations to other forms in this complex environment, with other mosquitoes, larvae from dragonflies, frogs, chironomids, etc.? How can one understand mosquito ecology if not by going into the woods, not necessarily as Henry Thoreau, who spent over two years in a Cabin in the jungle, feeling the nature, but under conditions to study and understand how mosquitoes live.

I am not sure of how many, who are the mosquito experts able to perform studies such as these, and I would like to know if someone knows. I know there are hundreds of young researchers able to assess and modify nucleic acids and protein sequences, struggling for a place in the sun and for funding. My impression is that entomology experts with knowledge, willingness and institutional support to perform ecology studies, in which taxonomy is essential, are an endangered species. Obviously, molecular biology experts are essential, inclusive to collaborate diagnosing mosquito infections and their taxonomy whenever necessary.

It is urgent to perform a delicate survey among the available medical entomology professionals and support the formation of new skilled professionals and ensure sufficient infrastructure for their work. When I speak of medical entomology, I do not mean some people trained a few hours in order to find Aedes aegypti larvae and identify them, but people adequately trained, if possible with doctorate studies, assisted by qualified technicians. Staff formation and the maintenance of medical entomology works is much cheaper than professionals from other fields are, and this species fundamental for public health must never be extinguished.

How many deaths in east Minas Gerais could have been avoided if there were quality surveillance, besides that which stands still waiting for the news to reach sanitary authorities (howler monkey deaths), to only then begin vaccination? Moreover, if the vectors were known in suspicious areas, how they live, when are they on trees or on the ground, at what hours of the day and under which weather conditions do they fly, which animals they prefer to bite, etc.? In hollow trees, it is known from works abroad, there is a great diversity, with complex interactions. How can we think about what and when to do if all we see are shadows on the caves walls? We are not killing the man that returned to tell the truth, as in Platos allegory, but letting him die from starvation, and with him, the poor victims of neglect. If the names and pictures of those who died from YF in Minas Gerais, victims of incomplete YFs epidemiology knowledge and little efficient surveillance, were aired on national TV, as are football players?

Are we going to stand still or fight to avoid more deaths? One death is a tragedy; one hundred thousand are statistics.

Are we going to stand still or fight to avoid more deaths?…