Over the past few weeks, news headlines have been dominated by the Zika virus, a disease that may be connected to birth defects in infants. The World Health Organization has declared Zika a Public Health Emergency of International Concern. The virus is spreading rapidly throughout Latin America and could spread to other parts of the world as well. Because Zika and malaria are both mosquito-borne diseases, we wanted to take a look at their similarities and differences in order to provide some insight.
Mosquito-borne diseases are responsible for the deaths of over one million people every year. Malaria, caused by a mosquito-borne blood parasite which has plagued humanity for Millennia, is the deadliest mosquito-transmitted disease. Due to significant investment in fighting malaria, the mortality rate has decreased by 60 percent since 2000.
Zika is an emerging mosquito-transmitted viral infection which is closely related to Dengue. Since its spread is relatively recent, scientists don’t know as much about it as malaria. What we do know is this: unlike malaria, the Zika virus is generally not lethal. Only about 1 in 5 people show symptoms, which are not typically severe and subside after a few days. However, of greater concern, the disease can be transmitted by a pregnant mother to her unborn child, possibly causing microcephaly (smaller than normal head size) in newborns. There are also reports that it may possibly spread through sexual activity.
Critical differences in the way that we fight these two diseases derives from the fact that they are spread by two different types of mosquitoes: malaria by Anopheles, and Zika by Aedes. Because Anopheles mosquitoes bite at night, malaria can be effectively prevented with the use of bed nets. However, Aedes feed during the day, which makes prevention more difficult. To avoid getting bitten by an Aedes mosquito carrying Zika, medical professionals advise using insect repellant and protective clothing. Efforts to reduce the populations of both types of mosquitoes are key to controlling both diseases, but also differ slightly in their approach.
Some countries have issued travel alerts advising pregnant women or women who may become pregnant to avoid countries with Zika outbreaks. The danger that Zika presents to pregnant women and their unborn children makes prevention of this disease critical – and right now there is no vaccine or treatment. Just today, the President announced that he will be asking Congress for over $1.8 billion in order to fight the spread of Zika.
Currently, Zika outbreaks are concentrated in the Americas, while malaria is most prevalent in sub-Saharan Africa. Both of these diseases have caused cases in travelers to affected areas, so if you are planning to travel be sure to learn more about risk and preventive measures on the CDC Travelers Health website.
For more information about Zika, you can watch this video by the Pan-American Health Organization (PAHO). You can also view the Center for Infectious Disease Research and Policy’s resource super page for the latest news and updates.