The Centers for Disease Control and Prevention (CDC) has issued an alert recommending enhanced precautions or postponed travel for people intending to travel to regions and certain countries where Zika virus transmission is ongoing.
The Zika virus is spread to people through mosquito bites. The most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis. The illness is usually mild, with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon.
However, in May 2015, the Pan American Health Organization issued an alert regarding the first confirmed Zika virus infection in Brazil. The outbreak in Brazil led to reports of pregnant women giving birth to babies with birth defects and poor pregnancy outcomes. This development, along with the absence of a vaccine, makes Zika a serious international health concern.
With the Olympic and Paralympic Games heading to Rio de Janeiro this summer, a leading scientist has warned pregnant women to carefully consider travel to the event. Laura Rodrigues, professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine, says Zika is probably responsible for the congenital birth defect epidemic known as microcephaly, when the brain of the fetus fails to grow normally.
With no vaccine or treatment, the only way to fight Zika is to clear stagnant water where mosquitoes breed, and to protect against mosquito bites by wearing long sleeves and trousers and by using insect repellant and mosquito nets. There have also been calls for some of the affected countries to delay pregnancy until more is known about the virus and its links to birth defects.
Brazilian authorities have announced plans to prevent the spread of the Zika virus during the Games. Inspections of Olympic facilities will begin four months before the event to get rid of mosquito breeding grounds. Daily sweeps will also take place during the Games. Fumigation would be an option only on a case-by-case basis because of concerns for the health of the athletes and visitors.
The following destinations are subject to the CDC travel alert, as of January 22: the Commonwealth of Puerto Rico, a US territory; Brazil; Colombia; El Salvador; French Guiana; Guatemala; Haiti; Honduras; Martinique; Mexico; Panama; Paraguay; Suriname; and Venezuela, Barbados, Bolivia, Ecuador, Guadeloupe, Saint Martin, Guyana, Cape Verde, and Samoa.
Specific areas where Zika virus transmission is ongoing are often difficult to determine and are likely to continue to change over time; consequently, travelers should monitor the CDC travel alerts frequently.
“Most [affected countries] are reporting sporadic cases but we have larger outbreaks in Brazil, in Colombia, in El Salvador, in Panama and in Cape Verde,” WHO Spokesperson Christian Lindmeier said.
“Microcephaly cases which have occurred now recently in Brazil stand at 3,893 reported suspected cases, with 49 deaths in 20 states of Brazil, and we have that one case reported out of Hawaii, an earlier traveler to Brazil,” he added, noting that the link between Zika and microcephaly is still being investigated.
According to WHO, teams are working with Brazil and other countries, including French Polynesia, where a larger outbreak of Zika virus hit in 2013 and 2014, attacking the nervous system of several patients.
WHO has warned that Zika is likely to spread across the Americas, following its rapid growth since November 2015. No locally transmitted Zika cases have been reported in the continental United States, but cases have been reported in returning travelers.
According to the CDC, the number of Zika cases among travelers visiting or returning to the United States will likely increase. These imported cases could result in local spread of the virus in some areas of the United States.
With Zika set to spread across the Americas, the hunt for a vaccine has begun. Scientists at the National Institute of Allergy and Infectious Diseases are currently looking for opportunities to fund research and development of treatment options.
Pharmaceutical companies are also beginning to look for solutions. GlaxoSmithKline, for example, is concluding feasibility studies evaluating whether its vaccine technology is suitable for the Zika virus. France’s Sanofi SA, which won approval late last year for the first dengue vaccine, is also exploring the possibility of developing a vaccine for Zika.
However, health officials agree there is no overnight solution and development of an effective vaccine could take years.
Stephen Higgs, Director of Kansas State University’s Biosecurity Research Institute, says that research is crucial to combating this outbreak and preventing the spread of other mosquito-borne viruses.
“One of the strengths that we have here at the Biosecurity Research Institute is the development of diagnostics and vaccine work," said Higgs. “That is exactly what is needed to enable timely responses to new diseases as they come along.”
While the institute is not currently performing Zika virus research, it does have isolates of the African lineage of Zika virus, which is similar to the Asian lineage involved in the current outbreak. University scientists have studied two similar mosquito-borne viruses: chikungunya, which affects humans and includes fever and joint pains, and Japanese encephalitis, which is found in pigs and birds and can transmit to humans through mosquitoes.
Higgs believes the Biosecurity Research Institute is equipped to help with any research that may find a solution for the virus. But until a solution emerges, mosquito control will be critical.
“Anybody traveling to those areas needs to be aware that there is a new virus in addition to the viruses already in the area, such as dengue fever or chikungunya,” Higgs said. "The same advice is for appropriate for everyone who goes to that area: Avoid being bitten by mosquitoes.”