World Health Organisation
The World Health Organization rang a global alarm over the Zika virus, saying that the disease was “spreading explosively” in the Americas and that as many as four million people could be infected by the end of the year.
WHO Director-General, Margaret Chan, will convene an International Health Regulations Emergency Committee on Zika virus and observed increase in neurological disorders and neonatal malformations. The Committee will meet on Monday 1 February in Geneva to ascertain whether the outbreak constitutes a Public Health Emergency of International Concern.
The situation today is dramatically different. Last year, the virus was detected in the Americas, where it is now spreading explosively. As of today, cases have been reported in 23 countries and territories in the region.
The level of alarm is extremely high.
Arrival of the virus in some places has been associated with a steep increase in the birth of babies with abnormally small heads and in cases of Guillain-Barre syndrome.
A causal relationship between Zika virus infection and birth malformations and neurological syndromes has not yet been established, but is strongly suspected.
The possible links, only recently suspected, have rapidly changed the risk profile of Zika, from a mild threat to one of alarming proportions. The increased incidence of microcephaly is particularly alarming, as it places a heart-breaking burden on families and communities.
WHO is deeply concerned about this rapidly evolving situation for 4 main reasons:
the possible association of infection with birth malformations and neurological syndromes
the potential for further international spread given the wide geographical distribution of the mosquito vector
the lack of population immunity in newly affected areas
and the absence of vaccines, specific treatments, and rapid diagnostic tests.
Zika virus disease is caused by a virus transmitted by Aedes mosquitoes.
People with Zika virus disease usually have a mild fever, skin rash (exanthema) and conjunctivitis. These symptoms normally last for 2-7 days.
There is no specific treatment or vaccine currently available.
The best form of prevention is protection against mosquito bites.
The virus is known to circulate in Africa, the Americas, Asia and the Pacific.
It is an emerging mosquito-borne virus that was first identified in Uganda in 1947 in rhesus monkeys through a monitoring network of sylvatic yellow fever. It was subsequently identified in humans in 1952 in Uganda and the United Republic of Tanzania. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific.
Zika virus is transmitted to people through the bite of an infected mosquito from the Aedes genus, mainly Aedes aegypti in tropical regions. This is the same mosquito that transmits dengue, chikungunya and yellow fever.
Zika virus disease outbreaks were reported for the first time from the Pacific in 2007 and 2013 (Yap and French Polynesia, respectively), and in 2015 from the Americas (Brazil and Colombia) and Africa (Cape Verde). In addition, more than 13 countries in the Americas have reported sporadic Zika virus infections indicating rapid geographic expansion of Zika virus.
Zika virus is diagnosed through PCR (polymerase chain reaction) and virus isolation from blood samples. Diagnosis by serology can be difficult as the virus can cross-react with other flaviviruses such as dengue, West Nile and yellow fever.
Mosquitoes and their breeding sites pose a significant risk factor for Zika virus infection. Prevention and control relies on reducing mosquitoes through source reduction (removal and modification of breeding sites) and reducing contact between mosquitoes and people.
This can be done by using insect repellent; wearing clothes (preferably light-coloured) that cover as much of the body as possible; using physical barriers such as screens, closed doors and windows; and sleeping under mosquito nets. It is also important to empty, clean or cover containers that can hold water such as buckets, flower pots or tyres, so that places where mosquitoes can breed are removed.
Special attention and help should be given to those who may not be able to protect themselves adequately, such as young children, the sick or elderly.