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Zika Virus Disease (ZVD)

Zika virus is an emerging mosquito-borne virus that was first identified in Uganda in 1947 in rhesus. 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.

Genre: Flavivirus

Vector: Aedes mosquitoes (Aedes Egypti)

Reservoir: Unknown

Signs and Symptoms:

The incubation period: is not clear, but is likely to be a few days.

The symptoms are similar to other arbovirus infections such as dengue, and include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache. These symptoms are usually mild and last for 2-7 days.

During large outbreaks in French Polynesia and Brazil in 2013 and 2015 respectively, potential neurological and auto-immune complications of Zika virus disease were reported.

Recently in Brazil, local health authorities have observed an increase in Zika virus infections in the general public as well as an increase in babies born with microcephaly in northeast Brazil.

Transmission:

Zika virus is transmitted to people through the bite of an infected mosquito from the Aedes genus, mainly Aedes Egypti in tropical regions (i.e. it 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.

Diagnosis:

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.

Prevention:

Prevention and control depend 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 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.

During outbreaks, spraying of insecticides or larvicides is advised to be carried; to treat relatively large water containers.

Travellers should take the basic precautions described above to protect themselves from mosquito bites.

Treatment:

Zika virus disease is usually relatively mild and requires no specific treatment.

People infected with Zika virus are advised to get plenty of rest, drink enough fluids and treat pain and fever with common medicines.

If symptoms worsen, they should seek medical care and advice. There is currently no vaccine available.

Medical Advice for Travellers to Zika-Infected Areas:

Zika-Affected Countries:

El Salvador, Venezuela, Colombia, Brazil, Suriname, French Guiana, Honduras, Mexico, Panama and Martinique, Bolivia, Guyana, Ecuador, Guadeloupe, Guatemala, Paraguay, Puerto Rico, Barbados, Saint Martin and Haiti, Jamica, Costa Rica, U.S. Virgin Islands.

Those intending to travel to Zika-affected countries should consider the following tips:

All travellers to the affected areas are advised to take individual protective measures to avoid mosquito bites.
Travellers, suffering from immune disorders or severe chronic illnesses, are advised to consult their doctor or seek advice from a travel clinic before travelling.
Pregnant women or those trying to become pregnant who plan to travel to Zika-affected areas , are advised to discuss their travel plans with their healthcare providers and to consider postponing their travel to those areas, especially ones with increasing or widespread transmission.
Saudi citizens, who live in Zika-affected areas, are advised to take individual protective measures to avoid mosquito bites. These measures should be applied particularly by pregnant women or those trying to become pregnant, living in areas with increasing or widespread transmission.
Individual protective measures to prevent mosquito bites should be applied all day long, especially during mid-morning and late afternoon to dusk, which are the periods of highest mosquito activity.
Personal protection measures to avoid mosquito bites should include:

Using mosquito repellents in accordance with the instructions indicated on the product label.
Using DEET-based repellents is not recommended for children under three months of age.
Wearing long-sleeved shirts and long pants, especially during the hours of highest mosquito activity.
Using mosquito nets, whether they are impregnated or not, is essential if accommodation is not adequately screened or air-conditioned.

Travellers, showing symptoms compatible with dengue, chikungunya or Zika virus disease within three weeks after returning from an affected area, should contact their healthcare provider and mention their travel experience there.
Pregnant women, who have travelled to Zika-affected areas, should mention their travel experience during antenatal visits in; order to be assessed and monitored appropriately.

WHO Response:

The World Health Organization (WHO) is supporting countries to control Zika virus disease (ZVD) through the following:

Strengthening surveillance.
Building the capacity of laboratories to detect the virus.
Working with countries to eliminate mosquito populations.
Preparing recommendations for the clinical care and monitoring of persons infected with Zika virus.
Defining and supporting priority areas of research into Zika virus disease and possible complications.