Zika Virus Response for the African Region

Summary of technical guidelines for Zika virus surveillance and response in line with the IDSR section 9 in the African Region

3 February 2016

I. Background

• Zika viral disease is transmitted through the bite of an infected mosquito, primarily Aedes aegypti. The virus was first identified in 1947 in rhesus monkeys in the Zika forest of Uganda, and was first identified in humans in 1952 in Uganda and the United Republic of Tanzania. Zika virus disease outbreaks were reported for the first time in the Pacific in 2007 and 2013 in Yap and French Polynesia, respectively. The geographical spread of Zika virus has since been steadily increasing.

• Zika virus disease has a similar clinical presentation to chikungunya and dengue, although it generally causes a milder illness. Symptoms of Zika virus disease include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache, which normally last for 2 to 7 days. There is no specific treatment for Zika virus disease, and it can be treated with common pain and fever medicines, rest and drinking plenty of water since symptoms are generally mild.
• Neurological complications have been reported in Polynesia and Brazil in 2013 and 2015 respectively concomitant with Zika virus outbreaks. Since October 2015 an increased number of microcephaly cases have been reported in Brazil. Although the cases are associated in time and space with the Zika outbreak, more robust investigations and research is needed to better understand this possible link. Other countries with current outbreaks such as Colombia, El Salvador, Cape Verde and Panama have not reported an increase in cases of microcephaly.

• Sporadic cases of human Zika virus disease have been detected in Africa for many years. However, since 2007 the presence of the virus has been confirmed in 8 Pacific islands, 25 countries and territories of the Americas, and some Asian countries. In the African region, Cape Verde has recently reported outbreak with over 7 000 cases from October 2015 to January 2016. However, the number of cases has been on the decline since December 2015 according to current data.

• The main vector for Zika virus, Aedes aegypti mosquito, is the same species that transmits Yellow fever, chikungunya and dengue viruses. Considering the wide distribution of this vector, all Member States in the African Region are at risk of Zika virus transmission. This risk is potentially increased by the ongoing Zika virus disease outbreaks in other countries in the world.

• At present, the only method of controlling or preventing Zika virus transmission is to combat the mosquito vectors using environmental management and chemical methods.

II. Surveillance goal

• Detect cases and outbreaks of Zika virus disease promptly and seek laboratory confirmation.
• Enhance community based disease surveillance.
• Enhance surveillance at points of entry
• Identify high-risk areas in order to improve prevention of outbreaks by taking steps to avoid mosquito bites and elimination of breeding sites.
• Identify cases with Zika associated complication for referral to hospitalized care.
• Enhance surveillance at pre/ante-natal clinics
• Support entomological investigations for vector surveillance
• Support operational research including new clusters of microcephaly and neurological disorders.

III. Standard case definition

Suspected Case*:
Patients with maculopapular rash and fever, presenting with one or more of the following symptoms (which are not explained by other medical conditions):
• Arthralgia or myalgia
• Non-purulent conjunctivitis or conjunctival hyperaemia
• Headache or malaise

* This case definition may change based on new knowledge.

Confirmed case:
A suspected case with a positive laboratory result for Zika virus infection using recognized techniques (see section VI Laboratory confirmation).

IV. Response to Zika virus disease

If Zika virus cases are suspected:

– Immediately report suspected cases to the next level using the case-based reporting form.
– Collect specimens for laboratory confirmation of cases (Emerging Dangerous Pathogen Laboratory Network (EDPLN)).
– Conduct active search for additional cases.
– Strengthen event-based surveillance to detect the emergence of clusters of cases presenting with rash and febrile syndrome of unknown aetiology.
– Conduct an investigation to determine the risk factors for transmission.
– Manage and treat the cases with supportive care.

If Zika virus cases are confirmed:

Coordination and leadership
– Reinforce the Incident management Systems to strengthen their coordination (including emergency operations center (EOC)) to include the preparedness to respond to Zika, dengue, chikungunya and yellow fever.
– Actively engage other sectors (environment, agriculture, tourism, infrastructure, etc.) to respond to Zika virus through a multisectoral approach (One Health approach).

Surveillance, data management and laboratory

– Notify WHO through Ministry of Health using the IHR decision instrument.
– Enhance surveillance of Zika virus and of the conditions that may be associated with it, including microcephaly and Guillain-Barre syndrome (GBS).
– Enhance surveillance at pre/ante-natal clinics to monitor possible congenital infections and complications.
– Conduct active search for additional cases
– Ensure the rapid and timely reporting and sharing of information of Zika virus disease using the IDSR/IHR tools
– Survey the community to determine the abundance of vector mosquitoes, identify the most productive larval habitats, promote and implement plans for appropriate interventions.
– Collect specimens for confirming of cases.
– Report any identified unusual increase in the incidence of congenital neurological malformations including microcephaly in neonates and adverse pregnancy outcomes, not explained through alternate causes, to the relevant public health authorities using IDSR framework.

Vector control and personal protection

– Intensification of efforts to reduce mosquito populations including the use of larvicide (insecticide that kills the mosquito in its larval stage) to treat potential breeding sites i.e. standing-water sites that cannot be treated in other ways (cleaning, emptying, covering or discarding) and adult mosquito control methods.
– Emptying or covering containers that can hold water, such as buckets, flower pots and tyres, so that mosquitoes cannot use them to breed.
– People protect themselves from mosquito bites 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; sleeping under mosquito nets including during the day when Aedes mosquitoes are most active.

Social mobilization, community engagement and communication

– Develop risk communication message to address population concerns, enhance community engagement, improve reporting, and ensure application of vector control and personal protective measures targeting reduction of contact with the vector.
– Provide women of childbearing age and particularly pregnant women with the necessary information and materials to reduce risk of exposure.
– Provide psychosocial support services for affected mothers and children.

Transmission prevention and case management

– Engage community health workers to inform them of the disease and risks and to build capacity
– Reinforce preventative measures for pregnant women through targeted interventions (including primary antenatal, postnatal and neonatal health care settings).
– Pregnant women who feel they may have been exposed to Zika virus may wish to consult with their health-care providers for close monitoring of her pregnancy.
– Evaluate foetus and infants of women infected during pregnancy for possible congenital infection and microcephaly
– Zika can be transmitted through blood, but this occurs infrequently. Precautions already in place for ensuring safe blood donations and transfusions should be followed.
– Ensure that pregnant women who have been exposed to Zika virus be counselled and followed for birth outcomes based on the best available information and national practice and policies.
– Refer most severe cases with complication to hospitalized cares.

Operational research

– Conduct studies including case-control studies to investigate the potential link between microcephaly and Zika virus.
– Promote research in the areas of vaccines, drugs, diagnostics, vector biology and appropriate mosquito control methods.

NB: Application of strategic intervention in different country contexts:

The described interventions will be packaged and applied in countries depending on the context. In countries where there is the spread of Zika virus as well as the associated complications, a full suite of strategies will be applied from enhanced surveillance, engaging communities, vector control and personal protective measures, care for people with complications and public health research better understanding the risk and mitigation measures.
For countries which are already experiencing the spread of Zika or have a prevalence of the Aedes vector, enhanced surveillance will be put in place, communities engaged, vector control and personal protective measures enhanced.
For all other countries risk communications for the public regarding trade and travel will be the main line of engagement. Table 1 below outlines the application of the strategies in the varying country context.

V. Analysis and interpretation of data

Time: Graph cases including Zika virus associated complications and deaths weekly. Construct an epidemic curve during the outbreak.

Place: Plot location of case households and work sites using precise mapping.

Person: Report case-based information for cases including Zika virus associated complication and deaths (Case-fatality rate). Analyze age and sex distribution. Percentage of Zika cases and of hospitalizations. Assess risk factors to improve prevention of outbreaks and to better understand the possible link of Zika with neurological complications.

NB: Entomological Analysis
In affected and high risk areas map infected and uninfected mosquito populations, breeding sites and case households etc.

VI. Laboratory confirmation


lab zika

Results Diagnostic services for Zika virus are not routinely available. Contact the appropriate National authority or WHO for the assigned reference laboratory within the EDPLN.

VII. References

1. Information note to the WHO representatives on prevention and response to Zika virus in the WHO African region, February 2016
2. Microcephaly/Zika virus disease talking points, 2 February 2016.
3. WHO statement on the first meeting of the International Health Regulations (2005) (IHR(2005) Emergency Committee on Zika virus and observed increase in neurological disorders and neonatal malformations
4. The 2010 IDSR second edition; http://www.afro.who.int/en/clusters-a-programmes/dpc/integrated-disease-surveillance/features/2775-technical-guidelines-for-integrated-disease-surveillance-and-response-in-the-african-region.html
5. Zika virus Fact sheet, Updated January 2016; http://www.who.int/mediacentre/factsheets/zika/en/