The Oswaldo Cruz Foundation, Brazil’s top public-health institute, recently discovered that yet another mosquito species can serve as a vector for the Zika virus. What makes this news troubling is that the species,
Culex quinquefasciatus, is far more common than the
Aedes aegypti species initially associated with the disease.
Mosquitoes of the
Culex quinquefasciatus species far outnumber their
Aedes counterparts 20 to one, the institute noted.
Culex quinquefasciatus bearing the Zika virus were found in the northeastern city of Recife, where the epidemic hit the hardest.
The unpublished findings suggest that Brazil might need to change its response strategy to the virus, now more potentially contagious than before. The country will need to quickly consider its options, as more travelers arrive in anticipation of the Rio Olympics.
“It’s very bad news for Brazil,” said entomologist Constancia Ayres, who conducted the research. It was Ayres that urged officials to look into other mosquito species other than
Aedes aegypti.
“We have a national program for controlling
Aedes – but we have nothing for
Culex – so if
Culex is an important vector then we have to start from zero,” she said.
Brazil’s Ministry of Health responded to the announcement, insisting that
Aedes aegypti remains the main vector of the virus. A spokesperson for the ministry told
The Globe and Mail that the findings do not change anything, as the public-health response is relatively the same for all types of mosquitoes.
Ayres and other entomologists have disagreed with the ministry’s stance, insisting that
Culex quinquefasciatus mosquitoes have slightly different behaviours than
Aedes aegypti. For instance, while
Aedes aegypti feed during the day
, Culex quinquefasciatus bite at night. Also, while the former species breeds in clean water, the latter prefers stagnant water.
Notably, Ayres’ findings could have repercussions outside of Brazil, as the
Culex quinquefasciatus species has a much wider range than
Aedes—the latter only thriving in tropical and subtropical regions.
It is unknown how much this announcement would affect travel insurance premiums until the findings are verified and officially recognised by the Brazilian government, although it is prudent to assume that significant increases are to be expected.
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