Posted By Prucia Buscell,
Monday, February 08, 2016
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Impact of Pathogen Reaches Beyond Health and Medicine
Zika won't be the last health crisis, says infectious disease expert Michael Osterholm, and we need to develop a comprehensive plan to combat microbial disasters instead of scrambling for multiple piecemeal short-term responses to confront the latest threat.
WHO has declared Zika a global health emergency. The CDC has warned pregnant women not to travel to mosquito prone areas. Though Zika was identified about 70 years ago, no vaccine is expected in the near future and researchers still have many questions about the disease. The virus has been found in human blood and urine. A few cases of sexual transmission, caused by the Zika virus in semen, have been discovered, though scientists don't know how long it lives in semen. The ebola virus has been discovered in semen months after the patient's recovery from the illness. The main Zika vector, though, is the Aedes aegypti mosquito, a wily, hard-to-kill enemy Dr. Osterholm describes as "the Norway rat of mosquitoes." It has evolved to live in close contact with humans and the trash humans create. It can lay eggs in a few drops of water in a bottle cap.
Dr. Osterholm writes that the habitat for Aeges aegypti breeding has increased dramatically over the last 40 years, with a world-wide explosion of plastic and rubber solid waste and non-biodegradable containers that collect water where mosquito eggs hatch. He says Aedes egypti has never been more numerous or lived in more locations. It is ubiquitous in warm and tropical regions and is present in 12 U.S. south eastern states. Aedes egypti's close cousin, known as the Asian Tiger mosquito, common in 30 states on the Eastern seaboard and Great Lakes region, isn't a significant factor in Zika spread, Dr. Osterholm writes, but if it becomes a more effective Zika transmitter, high risk will exist for a U.S. outbreak. Dr. Osterholm says we have to clean up our trash.
Some scientists have suggested a return to the banned pesticide DDT. Another controversial approach involves release of more mosquitoes-genetically modified males developed by the British biotech company Oxitec that have a gene designed to kill their offspring after they mate in the wild. (Male Aedes egypti don't bite people.) This could also blunt the spread of dengue and chikungunya, viral diseases that have no cure and are spreading quickly around the world.
More than 70 million Oxitec mosquitoes have been released in field trials in the Cayman Islands, Malaysia, Brazil and, most recently, Panama, all of which have struggled with dengue. Regulatory agencies in those countries approved the release of the mosquitoes, and last year Oxitec received approval from Brazil to release its mosquitoes commercially. But some critics fear the modified mosquitoes may actually foster disease spread. The Scientific American has been tracking Zika since the fall of 2015. Read the Scientific American Special Report on Zika.
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