WHO Declares Public Health Emergency Likely Tied to Zika Virus

AAFP Creates Educational Resource for Members

February 03, 2016 09:44 am News Staff

On Feb. 1, the World Health Organization (WHO) declared(www.who.int) the "recent cluster of microcephaly cases and other neurological disorders reported in Brazil" thought to be related to the Zika virus outbreak in Latin America a "public health emergency of international concern."

[World map showing transmission areas of Zika virus]

Countries and Territories With Active Zika Virus Transmission as of Feb. 1, 2016

This official emergency designation allows the WHO to globally coordinate action and funds from governments and nonprofit organizations to combat the Zika virus outbreak currently active in 25 countries and territories.

The declaration is a step the WHO has taken only three times before: during the H1N1 swine flu pandemic in 2009, the Ebola outbreak in West Africa in 2014, and the resurgence of polio in Syria and other countries in 2014.

WHO Director-General Margaret Chan said in a statement(www.who.int) that 18 experts and advisers assessed the threat posed by the Zika virus and the strong chronological and spatial associations between the infection and a rise in detected cases of congenital malformations and neurological complications. Those experts agreed that a causal relationship between Zika infection during pregnancy and microcephaly is "strongly suspected" but not yet scientifically proven.

Story highlights
  • On Feb. 1, the World Health Organization declared the "recent cluster of microcephaly cases and other neurological disorders" likely linked to the Zika virus a "public health emergency."
  • The CDC currently is working to determine if Zika virus and Guillain-Barré syndrome (GBS) are related because many of the Zika virus outbreak-affected countries are seeing spikes of GBS cases.
  • The CDC has released interim guidelines for U.S. health care professionals on caring for infants born to mothers exposed to Zika virus.

The committee also reviewed patterns of disease spread and the geographical distribution of mosquito species that can transmit the virus. The fact that no vaccine against the virus or rapid and reliable diagnostic tests to detect its presence exist also raised red flags, as did an absence of population immunity in affected countries.

A member of the Flaviviridae family, Zika virus is a single-strand RNA virus that is transmitted primarily via the bite of infected Aedes mosquitoes. However, perinatal, in utero, and possible sexual and transfusion-related transmission events have also been reported.

"After a review of the evidence, the committee advised that the recent cluster of microcephaly cases and other neurological disorders reported in Brazil, following a similar cluster in French Polynesia in 2014, constitutes an 'extraordinary event' and a public health threat to other parts of the world," Chan said in the statement. "In their view, a coordinated international response is needed to minimize the threat in affected countries and reduce the risk of further international spread."

The WHO recommends such a response "to improve surveillance, the detection of infections, congenital malformations and neurological complications; to intensify the control of mosquito populations; and to expedite the development of diagnostic tests and vaccines to protect people at risk, especially during pregnancy."

However, the committee found no public health justification for restricting travel or trade to and from affected countries to prevent further spread of the Zika virus. Instead, it said the top priorities should be to control mosquito populations and prevent mosquito bites in at-risk individuals, especially pregnant women.

Possible Tie to Guillain-Barré Syndrome

As reported by The New York Times,(www.nytimes.com) the Brazil Ministry of Health has seen a recent spike in the number of people diagnosed with Guillain-Barré syndrome (GBS), with hundreds now affected by the disorder.

First Case of Sexually Transmitted Zika Virus Detected in Dallas

On Feb 2, Dallas County Health and Human Services (DCHHS) announced(www.dallascounty.org) that the CDC had confirmed the first instance of Zika virus infection acquired through sexual transmission in Dallas County. The announcement also marked the first infection that originated inside the continental United States.

The patient was infected with the virus after having sexual contact with someone who had contracted Zika virus while traveling to Venezuela.

"Now that we know Zika virus can be transmitted through sex, this increases our awareness campaign in educating the public about protecting themselves and others," said DCHHS Director Zachary Thompson in the release.

Colombia currently has the second-worst Zika virus outbreak, and it, too, is experiencing a jump in cases of GBS. Health Minister Alejandro Gaviria said on Colombian radio this week that currently, the rate of GBS is 2.3 cases for every 1,000 patients diagnosed with Zika virus infection. The latest total was more than 20,000 cases of Zika virus infection in the country, including 2,100 in pregnant women.

Venezuela, another Zika virus-affected country, also has reported a recent increase in GBS cases from its normal average of 14 cases per month to 46 cases between Dec. 1 and Jan. 6, including two deaths.

And further supporting the possible connection, during a Zika virus outbreak in 2013 that affected more than 30 French Polynesian islands, scientists also reported a steep increase in GBS cases.

According to a CDC Q&A on the virus,(www.cdc.gov) it has not been confirmed that Zika virus infection causes GBS, and it is "difficult to determine if any particular pathogen 'caused' GBS." The agency currently is working to establish a relationship between the two.

Guidelines for Evaluating, Testing Infants for Zika Virus Infection

On Jan. 26, the CDC released a Morbidity and Mortality Weekly Report (MMWR)(www.cdc.gov) with interim guidelines for U.S. health care professionals caring for infants born to mothers who traveled to or resided in a country with Zika virus transmission.

Specifically, the CDC recommends testing infants for Zika virus if they have microcephaly or intracranial calcifications and were born to women who spent time in an area with Zika virus transmission while pregnant, as well as those who were born to mothers with positive or inconclusive test results for Zika virus infection.

Diagnosis of Zika virus infection is made through molecular and serologic testing, including reverse transcription-polymerase chain reaction (RT-PCR) for viral RNA, and immunoglobulin M enzyme-linked immunosorbent assay and plaque reduction neutralization test for Zika virus antibodies.

Health care professionals should contact their state or territorial health department to facilitate this testing, CDC officials advised. As an arboviral disease, Zika virus infection also is a nationally notifiable condition.

Also, for infants with laboratory evidence of a possible congenital Zika virus infection, additional clinical evaluation and followup are recommended.

Treatment of congenital Zika virus infection is supportive and should be individualized to address the specific medical and neurodevelopmental issues of each infant. The CDC said investigations are ongoing to better understand what services will be most effective for these children as they grow.

The CDC also released interim guidelines to aid health care professionals caring for pregnant women during a Zika virus outbreak.

AAFP Develops Zika Virus Resource

Health organizations have worked quickly to provide health care professionals and the general public with educational resources on Zika virus.

This includes the AAFP, which has created a resource that features updated information on the Zika virus outbreak -- including information on symptoms, diagnosis and management -- in an easily accessible format.

The resource also includes links to the CDC's extensive Zika virus resources for health professionals.

Related AAFP News Coverage
CDC Warns of Viral Illness Tied to Severe Birth Defects
Agency Advises Pregnant Women to Postpone Travel to Central, South America