- By Miguel Santos
Zika outbreaks spreads rapidly from Brasil
The Zika virus is likely to spread across nearly all of the Americas, the World Health Organization has warned.
The mosquito spread virus which causes the slow growth of the brain in fetuses leading to abnormally small head causes symptoms in adults including mild fever, conjunctivitis and headache. The virus has already been found in 21 countries in the Caribbean, Central and South America.
It has been linked to thousands of babies being born with underdeveloped brains and some countries have advised women not to get pregnant.
No treatment or vaccine is available.
The virus was first detected in 1947 in monkeys in Africa. There have since been small, short-lived outbreaks in people on the continent, parts of Asia and in the Pacific Islands.
The BBC working with data provided by the WHO have mapped out the current 2016 outbreak:
The virus’ current outbreak was first reported in Brasil in May 2015, the lack of any natural immunity in the population, ideal breading climates for mosquitoes and large number of native mosquitoes are thought to have contributed to this unprecedented rapid spread of the virus which not threatens to spread into the southern states of the USA.
Zika is transmitted by the bite of Aedes mosquitoes, which are found in all countries in the region except Canada and Chile.
In a statement, The Pan American Health Organization (PAHO), the regional office of the WHO, said: “PAHO anticipates that Zika virus will continue to spread and will likely reach all countries and territories of the region where Aedes mosquitoes are found.”
PAHO is advising people to protect themselves from the mosquitoes, which also spread dengue fever and chikungunya.
PAHO also confirmed that the virus had been detected in semen and there was “one case of possible person-to-person sexual transmission” but further evidence was still needed.
Around 80% of infections do not result in symptoms.
But the biggest concern is the potential impact on babies developing in the womb. There have been around 3,500 reported cases of microcephaly – babies born with tiny brains – in Brazil alone since October.
PAHO warned pregnant women to be “especially careful” and to see their doctor before and after visiting areas affected by the virus.
Approximately 25’000 children each year in the USA are affected by the virus that can cause head circumferences to be less than 31.5 cm at birth.
Colombia, Ecuador, El Salvador and Jamaica last week recommended women delay pregnancies until more was known about the virus.
Although officially PAHO says “any decision to defer pregnancy is an individual one between a woman, her partner and her healthcare provider”.
One resident near the Olympic Park in Rio de Janeiro said that the locals were living in fear of the virus : “Every one is at risk, we’re all scared of getting Zika. We’re surrounded with dirty, polluted water, but what can we do but put repellent on, to try to keep the mosquitoes away.”
Prof Laura Rodrigues, a fellow of the Brazilian Academy of Sciences and from the London School of Hygiene and Tropical Medicine, said some data suggested that up to one-in-fifty babies had birth defects in one of the worst hit areas, Pernambuco state in Brazil.
Rodrigues said: “Until November we knew nothing, this has caught us by surprise and we’re trying to learn as fast as we can.”
The cycle of contamination
Once the Zika virus has entered a mosquito and that mosquito bites a human, the virus lives in the blood, organs and bodily fluids of that human. When a non infected mosquito then bites this human the mosquito then becomes infected. The second mosquito then continues to infect numerous other humans who in return infect multiple other mosquitoes. The ability to spread so rapidly and across so many countries has scientists scrambling for a rapid solution.
The release of genetically modified sterile mosquitoes has previously proven to reduce natural mosquito populations by 90% in the release proximity.
GM mosquito release is currently the preferred strategy to combat the Zika outbreak that is being explored by several governments.
Brasil however is looking at the possibilities of daily fumigation of the Olympic village but only in the build up to the Olympics, a move which has angered many local residents whom for a long time have felt that the local government have been putting the concerns of tourist above the needs of the local residents.
For the immediate time all persons are advised to take all and any reasonable precautions to prevent mosquito bites. Intimacy between a non infected person and an infected person is not advised in many countries where it is believed to be also passed on from human to human by bodily fluids. This however requires more research until it can be proven as a common form of transmission. There have been a small number of cases of human to human transmission during the current outbreak.