The Zika virus outbreak may have been set off by exceptionally dry and hot temperatures in Northeast Brazil, a new preliminary study revealed.
Scientists say that because the Aedes mosquito, the carrier of the Zika virus, multiplies faster in warmer climates, Northeast Brazil's dry winter and spring may have encouraged the surge in the growth rate of these insects.
"The extreme temperature and drought are due to a combination of the El Niño phenomenon and the climate changes of recent years," said Dr. Shlomit Paz, lead author of the study and a faculty member of the University of Haifa in Israel.
This week, the World Health Organization declared a state of emergency in parts of Latin and Central America. What's more, the outbreak was recently associated with the downpour of heavy rainfall in these areas as a result of El Niño.
Paz and her colleagues, however, believe that El Niño steered the outbreak from a different direction.
Heavy rainfall is not the relevant factor, the team said. It was the wave of extremely hot and dry weather that Northeast Brazil experienced in the past few months that caused the mosquito to quickly spread the virus.
The team based its findings on late 2015 data from the National Oceanic and Atmospheric Administration (NOAA), during spring and winter season in Northeast Brazil. Data revealed that the highest temperature records began at this part of 2015, as well as the beginning of severe drought. The Zika outbreak had then appeared in Northeast Brazil in the weeks that followed.
Paz said the heat and drought were the result of two factors: El Niño, which has caused the rise of water temperatures in the Pacific Ocean and Latin America; and the patterns of global warming and climate change, which have been afflicting the planet over the recent decades.
Aedes mosquitoes need water to reproduce, and the dry weather in Northeast Brazil should have been a hindrance, but studies have shown that during periods of drought in the area, residents stored water in containers, consequently giving these insects their own convenient habitat.
When combined, extreme weather conditions and the residents' response to these conditions created the ideal surroundings for rapid increase of Zika-carrying mosquitoes, researchers said.
Paz also said that the fact that Aedes mosquitoes are also carriers of other viruses such as chikungunya and dengue fever makes it highly important to address the effects of climate in relation to the causes of the current outbreak.
As this is only a preliminary study, Paz and her colleagues will be expanding their research to further understand this link. The current findings are featured in the journal The Lancet.
Photo : Maria Hsu | Flickr
