As some 600 disease experts from 43 nations convene in the French capital to pour over increasingly troubling data about Zika, it appears that there’s not much room for optimism anytime soon.
The World Health Organization (WHO) warned yesterday of the potential for a “marked increase” in Zika infections as well as the spread of the virus to new parts of the world.
At present largely confined to Latin America and the Caribbean, Zika’s range is thought likely to expand as summer arrives in the northern hemisphere, bringing with it virus-transmitting mosquitoes.
“As seasonal temperatures begin to rise in Europe, two species of Aedes mosquito which we know transmit the virus will begin to circulate,” WHO assistant director general Marie-Paule Kieny told the Zika science conference in Paris.
Add to that the risk of Zika-infected men passing the virus on to women via sex, and the world “could see a marked increase in the number of people with Zika and related complications,” Kieny said, describing Zika as a “global emergency” and a “growing threat.”
AFP reports that despite a flurry of research, very little is known about the virus — how long it can hide out in the human body, the degree of risk of sexual transmission, the full list of diseases and disorders it may cause, and all the mosquito types capable of transmitting it.3
Recent scientific consensus is that Zika causes microcephaly, a form of severe brain damage in new-borns, and adult-onset neurological problems such as Guillain-Barre Syndrome, which can cause paralysis and death.
But as infectious diseases professor David Heymann of the London School of Hygiene and Tropical Medicine told AFP on the conference sidelines: “It’s not what we know but what we don’t know that is concerning.
“We can’t make recommendations (for prevention) if we don’t understand the full potential of a virus or bacteria.”
Currently, there is no vaccine or treatment for the virus, which in most people causes only mild symptoms – a rash, joint pain or fever.
But according to Kieny, the most urgent priority, was for new tools for quickly diagnosing Zika, particularly in pregnant women whose babies risk severe disability.
Kieny said that developers in the United States, France, Brazil, India and Austria are working on 23 vaccine-development projects, but it could take years, and the feasibility of an “emergency-use” vaccine was being examined.
The experts said that until then, the first line of defence remained mosquito control and bite prevention, and advising women in endemic regions to postpone pregnancy.
Duane Gubler of the Duke-NUS Medical School in Singapore, said Zika “surprised” the world, just as Ebola before it, despite both viruses having been known about for decades.
“I think we should take this as a wakeup call and start developing our surveillance systems so we can monitor these viruses a little more effectively,” he told the conference.
Kieny said particular vigilance was required in Africa, where the virus was first discovered in Uganda in 1947.
The virus can be introduced to a new region when a local mosquito picks it up from an infected human, such as someone returning from a vacation in South America.
Provided the mosquito lives long enough, it then infects people from whom it takes a blood meal, starting a vicious cycle.
Zika virus was discovered in 1947. Why was it ignored for so long? https://t.co/0kNvTTHSuc pic.twitter.com/KqXd2N2iDe
— The Economist (@TheEconomist) April 25, 2016
The current Zika outbreak in Brazil began early last year, followed nine months later by a surge of infants born with microcephaly, and an increase in Guillain-Barre cases.
Brazil has reported some 1.5 million infections out of an estimated global total of two million in more than 40 countries.