Health Experts Weigh In On Zika Risks And Potential For Future Outbreaks
By Ed Miseta, Chief Editor, Clinical Leader
Unless you’re living in a cave or have been able to seclude yourself from all media the last couple months, you’ve no doubt heard of the Zika virus. After arriving in Brazil in May 2015, the mosquito-borne illness is spreading rapidly in the Americas and appears to be linked to congenital defects in babies and Guillain-Barre, a nervous system disease. At least one case last week was believed to have been spread via sexual contact.
The outbreak and potential for future outbreaks in other areas of the world has many health professionals and organizations concerned. The European Society of Clinical Microbiology and Infectious Diseases (ESCMID), which promotes research, risk assessment, knowledge sharing, and best practices in the fight against infectious diseases, is one of those organizations.
The group is now developing tool to monitor the spread of the Zika virus and is gathering data to better assess the risks associated with it. ESCMID believes researchers need to find evidence of how the virus affects the body, what is causing the spread of the virus in the Americas, how else it can be spread other than by mosquito bites, and what the link is to babies and the nervous system.
The 2016 Olympic games are scheduled to be held in Rio de Janeiro. In a recent report on the Zika virus, researchers including several from ESCMID discussed the threat that may be posed to residents in Brazil as well as attendees to the Olympic games. Researchers are also scrambling to better monitor the spread of the virus as concerns grow of the potential for an outbreak in Europe and a return of Zika to Africa where it was first isolated to the Zika Forest in Uganda in 1947.
In a paper published in the International Journal of Infectious Diseases, Professor Alimuddin Zumla of University College London and Professor Eskild Peterson from Aarhus University in Denmark and executive committee member of the ESCMID group on Infections in Travellers and Migrants (ESGITM) conclude molecular analyses of the virus are urgently needed to understand whether a change in the virus might be responsible for the current rapid spread and its association with microcephaly in babies exposed during pregnancy.
According to Prof. Petersen, “Specific and rapid diagnostic tests for the virus will allow better surveillance and assessment of the risk for microcephaly, Guillain-Barré syndrome, and other complications. The emergence of Zika virus soon after the Ebola outbreak is yet another reminder for the urgent need for a coordinated global effort to have sufficiently resourced rapid response groups for proactive surveillance and conduct of priority research in emergency situations.”
When outbreaks like the current one occur, they often originate in countries with poor resources and infrastructure to deal with the virus. The lack of proper resources can also contribute to issues around a proper diagnosis and control of the outbreak.
Mosquitoes Are The Culprit
Dr. Nick Beeching, an ESGITM board member from the Liverpool School of Tropical Medicine states the Aedes mosquitoes, which have been implicated in the outbreak, are widespread in the tropics. Scientists are currently focused on two specific varieties of the mosquito, the Aedes aegypti which is responsible for the outbreak in Latin America, and Aedes albopictus, which is found in southern Europe. The two varieties are not unknown to researchers, and are already responsible for epidemics of fevers due to dengue and chikungunya viruses in the tropics as well as smaller outbreaks in Italy and France. Additional research is needed to determine if other types of mosquitoes in Europe can also spread the virus.
According to Beeching, only one in five people infected with the virus will show any symptoms. As a result, many people will not be aware that they have been infected. He believes it is likely the virus will return to sub-Saharan Africa soon, as it is already present in Cape Verde, an island off the coast of Western Africa.
“The next stage for the virus might be to move from Cape Verde to Guinea-Bissau, and from there to neighboring countries in West Africa,” he says. “It could also be exported to Madeira, which is part of Europe, and which experienced a dengue fever outbreak in 2012, transmitted by Aedes mosquitoes that were already established there.”
Rapid Spread Is A Concern
One question that remains to be answered is why the virus was able to spread so rapidly, when huge outbreaks of the virus had not previously occurred. While a mutation of the virus is certainly a possibility, we will not know for sure for at least a couple of months until the RNA of the virus is analyzed. Investigations into the associations with central nervous system complications may prove particularly important, which will include follow-up with patients and babies born to infected mothers.
Individuals have an infection risk if they travel to affected countries or have unprotected sexual contact with someone who has recently returned from an affected area. There is also a risk from transfusion of blood donated by those recently infected. If the virus does happen to reach southern Europe, researchers are concerned about countries like France, Spain and Italy, which registered cases of dengue transmission in the past.
Dr. Rogelio López-Vélez, ESGITM member from the Spanish national referral center for tropical medicine of the Hospital Ramón y Cajal in Madrid, adds, “If the virus spreads to Africa and Southern Europe, we urgently need rapid diagnostic tests and more information on how long the risk of microcephaly exists after infection. For now however, particularly among female migrants from South America or Europeans visiting Latin America, we need to ensure they remain vigilant when travelling between the two continents.”
Researchers at the Scripps Research Institute are currently working on a cure, and have been studying the virus since prior to the current outbreak. The institute is currently seeking grants to continue their research, and have shifted resources from other viruses into the Zika project. Scripps, which has studied similar diseases such as West Nile and Dengue Fever, believes a vaccine is still a few years away.
Other companies pursuing a vaccine are pharma giants GSK and Sanofi, as well as Inovio Pharmaceuticals. Inovio’s MERS vaccine, which may hold promise for a future Zika vaccine, is currently entering clinical trials. Hemispherx Biopharma is also exploring Zika research programs based on a clinical trial of Alferon to treat the closely related West Nile virus.