Exceptionally hot and dry winter in northeast Brazil may be linked to outbreak of the zika virus

A preliminary study undertaken at the University of Haifa and the European Center for Disease Prevention and Control (ECDC) has found a linkage between the exceptionally hot and dry winter and spring recently experienced in northeast Brazil and the outbreak of the zika virus. "The extreme temperature and drought are due to a combination of the El Niño phenomenon and the climate changes of recent years," says Dr. Shlomit Paz, who undertook the study, which was published in The Lancet.

The World Health Organization this week responded to the serious outbreak of the zika virus, which is transmitted by the Aedes mosquito, by declaring a state of emergency. The outbreak has recently been associated with heavy rains in parts of Latin and Central America as a result of El Niño. However, the new and provisional findings of the study, undertaken by Dr. Paz from the Department of Geography and Environmental Studies at the University of Haifa, together with Professor Jan Semenza of the Stockholm-based European Center for Disease Prevention and Control, suggest El Niño was actually involved in a completely different direction. The relevant factor is not the heavy rain -- which actually fell in areas far removed from the outbreak -- but the wave of exceptionally hot and dry weather experienced over recent months in northeast Brazil, the area where the Zika virus erupted.

According to the findings, based on data from the US agency the National Oceanic and Atmospheric Administration (NOAA), the latter half of 2015 -- the winter and spring season in the southern hemisphere -- saw the highest temperatures since records began, combined with severe drought. The Zika outbreak appeared in these areas over the weeks that followed. Accordingly to Dr. Paz, the exceptional heat and drought were caused by a combination of two factors: Firstly, El Niño, a phenomenon that includes a substantial rise in water temperatures in the Pacific Ocean off Latin America. This phenomenon is known to cause drought in northeast Brazil, and in recent months the El Niño phenomenon has been particularly strong. The second factor is the patterns of global climate change and warming that have affected the entire planet over recent decades.

Dr. Paz adds that it is known that high temperatures (up to a certain limit) encourage an upsurge in the growth rates of the Aedes mosquito, which carries the zika virus. These mosquitoes also require water, and as noted the past six months were not only unusually hot, but also extremely dry. However, previous studies in the area have shown that during periods of drought, local residents store water in containers, thereby creating a convenient habitat for the mosquitoes. Accordingly, the combination of the extreme weather conditions and local residents' response to these conditions created the ideal conditions for the proliferation of the mosquito population.

As noted, this is a preliminary study. The researchers are currently expanding the study in order to gain further insight into the precise nature of the linkage between climatic conditions and the outbreak of the disease. "In light of the health risk, and the fact that the Aedes mosquitoes also carry other viruses, such as dengue fever and chikungunya, it is important to address the impacts of climate which we have found when analyzing the causes of the current outbreak," Dr. Paz concluded.

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The above post is reprinted from materials provided by University of Haifa.
Bron:http://www.sciencedaily.com/releases/2016/02/160204112335.htm

Brazilië gaat zikavirus bestrijden met gammastraling

Het Internationaal Atoomenergieagentschap wil Brazilië helpen in de strijd tegen het zikavirus. De VN-organisatie maakte maandagavond bekend dat zij betaalt voor het verschepen van een apparaat waarmee muggen kunnen worden gesteriliseerd.Miljoenen mannetjesmuggen worden onvruchtbaar gemaakt door gammastraling. Zodra ze gesteriliseerd zijn, worden ze uitgezet zodat ze met vrouwtjes kunnen paren. De eitjes die worden gelegd zijn dan niet bevrucht. Deze methode moet het virus een halt toe kunnen roepen.

Het stralingsapparaat staat nu nog in Portugal en wordt naar Brazilië gehaald zodra de regering toestemming geeft.

Het zikavirus zou grote schade kunnen toebrengen aan de hersenen van ongeboren baby's. Het virus wordt overgebracht door besmette muggen en is momenteel vooral een groot probleem in Midden- en Zuid-Amerika.

Vaccin

Vanwege de Olympische Spelen in Rio de Janeiro in augustus zijn de autoriteiten druk op zoek naar een oplossing. Er is nog geen vaccin, waardoor het virus alleen bestreden kan worden door de muggenpopulatie te verminderen.

Naast gammastraling kijken onderzoekers ook naar genetisch gemanipuleerde muggen. Die gaan dood voordat ze zich voortplanten.
Door: ANP
Bron: http://www.nu.nl/zikavirus/4219060/brazilie-gaat-zikavirus-bestrijden-met-gammastraling.html | Gewijzigd: 31 januari 2017, 14:04 uur, door Joyce.s