By Douglas MacQueen, MD
The Zika virus has been making national headlines and the World Health Organization has recently declared it to be an international public health emergency. There is no reason for residents living in upstate New York to fear an outbreak here. However, women who are pregnant or are in the process of trying to start a family should take certain travel precautions.
What is the Zika virus?
Zika is a viral infection that was first described in the 1950s in Africa, with limited outbreaks in Asia and the South Pacific since then. The virus is spread by the Aedes aegypti mosquito, which is the same mosquito that transmits dengue and Chikungunya. For the virus to spread, mosquitoes of the Aedes genus must take a blood meal from a human who has the virus and then bite another human, thereby transmitting the virus to them.
Until recently, the Zika virus had not been seen in the Western Hemisphere but it is now present in South America, Central America, Mexico, and the Caribbean. In the United States, the Aedes aegypti mosquito is common in southern Texas and Florida, where the climate is warm and moist enough for this tropical insect to live. This means there is the potential for Zika to be transmitted in those particular regions of the country. As our climate warms, we need to consider that the range of these mosquitoes may spread northward, changing our risk for tropical infections like Zika. Other Aedes mosquitoes like the Asian tiger mosquito live throughout the southeastern U.S. and are potentially able to transmit Zika. If it does, more of the U.S. population could be at risk of Zika infection in the future.
Why is the Zika virus considered such a serious risk?
Zika is spreading rapidly in warmer parts of this hemisphere because people here have not been exposed to it before, which means they have no immunity to it. In some areas, a higher rate of microcephaly has been detected in babies born to mothers who had Zika infection. These babies are born with smaller than normal skulls and brains, in many cases leaving them with developmental delays and intellectual deficits. The exact relationship between the virus and microcephaly is not clear yet. However, we do know that Brazil is reporting increasing numbers of people infected with the virus and an increase in the number of babies born with microcephaly. Other viruses acquired during pregnancy are known to cause microcephaly, so it would not be surprising if Zika infection did, as well.
What are the symptoms of Zika virus and how is it treated?
People infected with the virus experience either no symptoms or mild flu-like symptoms, including fever, sweating, aches, and sometimes a rash. Unique to Zika are red, inflamed outer eyes, in which the whites of the eyes are bloodshot and irritated. The symptoms resolve over a few days. Currently an effective vaccine is years away. People sick with the virus should rest, drink lots of fluids and use anti-inflammatory medication for aches and fever.
Is there a modern-day precedent for this type of viral epidemic?
Yes, in 2013 the Chikungunya virus, also spread by Aedes mosquitoes, appeared for the first time in the Caribbean Islands. It quickly became widespread throughout the Caribbean. Small outbreaks also occurred in southern Texas and Florida where the Aedes mosquito was present. These outbreaks were short lived, likely because of effective mosquito control in the U.S. ItÕs also possible that other environmental factors present in the southern U.S. have prevented a large scale outbreak of the virus. The Chikungunya virus remains present in the Caribbean, but much of the population there have been infected, so outbreaks are less common. Non-immune travelers to the area are still at risk.
What preventive steps should we take?
For now and the foreseeable future, Americans traveling to the Caribbean, Mexico, Central America and South America are at risk for contracting Zika virus. Wear long pants and shirts and use insect repellant when travelling in those areas. Pay particular attention during the day as Aedes mosquitoes are most active during the daytime. If you are pregnant or trying to become pregnant, avoid traveling in these regions. The virus is also spread through sex with someone who is infected with it; so choose your partners wisely.
Dr. MacQueen is board certified in internal medicine and infectious diseases. He is on the medical staff of Cayuga Medical Center and can be reached at the Cayuga Center for Infectious Diseases at (607) 241-1118.