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Zika-spreading mosquito sends chikungunya cases soaring in Brazil

25 November 2016

Brazil's health ministry said cases of chikungunya were soaring this year in the country.

According to the ministry, there had been 134,910 confirmed cases of the mosquito-borne disease so far in 2016 as against the 8,528 over the last year.

Chikungunya, a viral disease, was spread by the Aedes aegypti mosquito. It also transmitted the Zika virus and dengue fever.  People with chikungunya experienced fatigue, nausea, high fever and joint pain or swelling.

Experts had linked the Zika virus to microcephaly, a rare defect that could cause babies to have smaller than normal heads and improperly developed brains.

According to the ministry more than 2,159 cases of microcephaly had been confirmed in Brazil since October 2015.

According to experts the Aedes aegypti species of mosquito had proved to be the most dangerous as the tiny mosquito had claimed millions of victims across the globe over hundreds of years.

''One of the most efficient killers in the world,'' Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, told The Washington Post this year in discussing A. aegypti.

Travel, global commerce and a warming planet only seemed to be helping the mosquito to again flourish after widespread eradication efforts in the first half of the 20th century.

Writing Thursday in the journal Science, Yale University's Jeffrey R Powell, a professor of ecology and evolutionary biology, detailed how the species now bred year-round in locations where it once did not exist.

''These expansions are putting at risk large human populations that never experienced aegypti-borne viruses and therefore have no immune defenses against them,'' he wrote. ''This greatly increases the likelihood of severe epidemics.''

According to Powell researchers had documented two subspecies of A aegypti - the human-loving ''Aaf'', traditionally found in forests - interbreeding in certain parts of the world from Argentina to Africa. ''The consequences of increasing hybridization between the two subspecies remain unclear,'' he continued. He warned that it could lead to increased genetic variation and still more spread of disease.

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