Flaws in epidemiological disease and vector surveillance affect public health actions

Misdiagnosis for Oropouche fever, many times mistaken as dengue, troubles actions against the diseases


For Dr. Pedro Tauil, factors as urban population explosion in the world reduce the effectiveness of combat actions against the Aedes aegypti

Controlling diseases transmitted by insects that still do not have vaccines or effective and safe etiological treatment, passes, primarily by vector combat and correct diagnostic. However, flaws in these two aspects can jeopardize public health actions.

This pictures the combat against one of the greatest national enemies: the Aedes aegypti mosquito, transmitter of the Dengue, Chikingunya and Zika viruses. Despite the annual campaigns along with the population – as alerts for the dangers of still water and need of using insecticides, the three diseases are epidemic in great part of the country.

Dengue data, for example, are alarming. The Health Ministry has recently announced that 1.59 million people were victimized last year, referring only until December 5th. This is almost three times greater than in 2014 (555.4 thousand).

For Dr. Pedro Luiz Tauil , PhD in Tropical Medicine, the country lacks of innovation when responding to the Aedes. He quotes several aspects that hamper the actions from being very effective, as urban population explosion, with a large number of people living with precarious sewage and housing conditions, and the modern industrys preference for disposable packaging. Besides this, another risk factor is the huge vehicle production, that leads to inadequate used tire disposal – the perfect environment for the mosquito proliferation as they act as larvae deposits.

Studies in progress try to find more effective control measures. Some ideas include the use of transgenic mosquitos, larvicides carried by the own insect and event infecting the A. aegypti with bacteria that would make them unable to transmit diseases. We have been looking for more effective vector control measures, with foreign techniques that are already being tested in Brazil, says Dr. Tauil.

Recently, due to a microcephaly outbreak in fetuses related to Zika virus infection , the federal government has intensified control actions against the mosquito. Besides increasing personnel training in states and cities to identify the mosquitos proliferation sites, insecticide and combat kits are being handed out to the population. Even troops of the Brazilian Army help dismantling the mosquitos proliferation sites.

Dengue vaccine

Dr. Tauil defends the actions must receive extra support even after a recently-released dengue vaccine. This is because the product has a restricted effectiveness, besides, it is not effective against other diseases transmitted by the Aedes.

This vaccine is still not the ideal, because it cannot be used in children under the age of 9 and in people over 45 years old (priority group), besides not protecting the same way against the other four serotypes. Despite truly being another weapon against dengue, the product only offers a 50% protection against serotype 1, 42% against serotype 2, 74% against serotype 3 and 77% against serotype 4. Besides this, one must take three doses every 180 days.

The physician reminds that, despite all howevers, the vaccine has significantly reduced hospitalizations by the severe form of the disease in the agegroup from 9 to 45 years. The Federal Government, however, has still not decided if the vaccine will be included in the National Immunization Program and if only priority groups will be granted, according to the doctor.

Lack of diagnostic

Dr.Luiz Tadeu Figueiredo , in an interview to the Brazilian Society of Tropical Medicine (BSTM), published on December 2014, alerted for the diagnostic problem for a disease similar to dengue, the Oropouche fever.

Besides combating the Aedes, the control of one of the main vector-borne diseases that most affect Brazilians needs more attention from the Countrys epidemiological surveillance system. This applies to Oropouche fever under-report, a disease that is usually benign disease that lasts from three to five days. Despite not very well known, it can represent up to half of the cases thought to be dengue in Brazil.

The lack of diagnostic many times hampers the public health actions against these diseases. Among other reasons, because the transmitting mosquito is not the A. aegypti, but another very common insect in the Country, the marauim (Culicoides paraenses). The vector is common around jungles in great part of Brazil, including large cities, as Rio de Janeiro.

The main diagnostic errors are due to problems as clinical exam: since the Oropouches symptoms are similar to dengues, the doctors bet on the latter. Besides this, a Oropouche-infected persons serological exam could return a positive result for dengue After dengue, this is the second virus to infect most people in Brazil. The first urban outbreak took place during the 1960s and, recently, epidemics were reported in Pará State, with over 30 thousand cases, and in Amazonas State.

This January, a teenager from Ribeirão Preto (SP) who was in vacation in the Northeast, was diagnosed with Oropouche fever. This is one of the first two cases to be reported outside the Amazon.…