what causes the zika virus

the zika virus was first discovered in a forestin uganda in 1947--but the first outbreak in the americas occurred last may all overbrazil. there are two theories about it arrived there: 1, it was brought by the crowds of fans arrivingfor the 2014 world cup that brazil hosted in 12 cities across the country. or, 2, afew weeks after the world cup, it was brought by members of the teams of canoe racers inthe va’a world sprint in rio who had come from several polynesian islands. but regardless of how it got to brazil, zikaspread rapidly once it was there, infecting millions of people. because no one in thewestern hemisphere had been exposed to it

before--they hadn’t developed immunity.it’s transmitted mainly by the extremely common aedes aegypti mosquito, although therehave been a few cases of it spreading through sex. 80% of people infected have no symptoms, andfor the 20% that do, most are mild and flu-like and don’t last too long. but some suffera temporary paralysis called guillain–barr㩠syndrome, and for women who become infectedwhile pregnant things get downright scary, since the spread of zika has coincided withan unusual spike in the number of babies born with microcephaly, a rare congenital conditionresulting in an abnormal smallness of the head. and 80% of those born with microcephalyhave incomplete brain development.

but given how quickly the outbreak has poppedup and spread, scientists can’t be 100% sure that zika is directly causing the uptickin cases of microcephaly, but a more than 1,000% increase in suspected cases in brazildirectly correlating with the explosion of zika means they’re preeeetty sure it is. so to avoid this danger, the american centersfor disease control and prevention is advising pregnant women to avoid these countries, whichcorrespond with the probable range of the yellow fever mosquito. the governments of colombia and el salvadorhave advised women living there to avoid getting pregnant altogether for the foreseeable future.it’s also important for everyone there to

minimize exposure to mosquito bites. dã©bora diniz, founder of the brazilian instituteof bioethics adds this point: “[zika] is concentrated among young, poor,black and brown women, a vast majority of them living in the country’s least-developedregions...they live in substandard, crowded housing in neighborhoods where stagnant water,the breeding ground for disease-carrying mosquitoes, is everywhere.” the crisis also disproportionately burdenspoor communities, where women have less access to birth control, pre- and post-natal medicalsupport, and safe options for abortion, which, in brazil for example, are almost always illegalin a country that’s 65% roman catholic.

recently, the world health organization declaredthe zika virus a global health emergency to prompt coordinated action to fight it. thewho’s proactive response comes after it was heavily criticised for responding tooslowly to the ebola outbreak of 2014. experts say that a place like haiti, withhardly any public health infrastructure, could be facing tens of thousands of cases of microcephalicbabies by the end of the year if strong, immediate action isn’t taken. so the who is having to walk a fine line politicallybetween compelling governments to act, and causing a panic that could hurt the economiesof the affected countries, which would compound their problems. rio de janiero’s hostingof the summer olympics in august is the perfect

example of the need to manage the perceptionof how dangerous zika really is. to its credit, the brazilian government haslaunched a widespread effort to control its mosquito population, but that’s not easyin a country that’s home to the world’s largest forest. in the united states, where mosquito controlprograms are widespread and effective, the risk of a homegrown outbreak appears low.still, the cdc predicts zika to continue spreading in puerto rico, with outbreaks in florida,some gulf coast states and maybe hawaii. but despite a surge in media interest surroundingmicrocephaly and zika, as of february 2nd, brazilian health officials have investigated23% of the 4,783 suspected cases of microcephaly,

confirming just 404 out of the 1,113 they’velooked at so far. so if that rate holds up for the rest of the suspected cases, therewill be around 1,700 confirmed cases of microcephaly in brazil. it’s a lot harder though to find zika inthese confirmed cases of microcephalic babies, as only 17 of the 404 have been directly linkedto the virus. this means there’s still a lot of work tobe done to solve the mystery of if and how zika is causing brain damage in babies. ucsan francisco virologist lenore pereira explains why it’s so important, “if we understandhow the virus infects cells, we can come up with ways to suppress it.”

for the latest information on microcephalyand the zika virus, check out the link to the cdc’s website below. if you found this explanation helpful, hitthat like button to share it with others. until next time, i’m bryce plank and, asusual, thanks for watching.

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