In the 1940’s, scientists in Uganda discovered a breathtakingly beautiful forest on the edge of Lake Victoria, near Entebbe. The Zika Forest, originally spelled Ziika meaning “overgrown” in the local language, proved to be a valuable resource to virologists studying all varieties of disease (Kron, 2016). The Uganda Virus Research Institute (UVRI) of Entebbe established a protection program for the forest in order to maintain a satellite location for extended research studies.
Research here in 1947 revealed the first detection of its namesake, the Zika virus (Aggarwal et al, 2016). Initially isolated in a Rhesus monkey, the Zika virus was identified as a flavivirus that is transmitted by mosquitoes. Detection of the virus in the human population first occurred in 1952, while the first major outbreak occurred on the Pacific Island, Yap, in 2007 (Aggarwal et al, 2016). Major epidemics, in 2013 and 2014, were reported in French Polynesia, New Caledonia, the Cook Islands, and on Easter Island. By May 2015, the virus had spread to the country of Brazil and was working its way across the Americas (Mlakar et al, 2016).
On Monday, February 1, 2016, the World Health Organization issued a global health emergency concerning the Zika virus. By December 2015, an estimated 440,000 to 1.3 million people had been infected in Brazil alone, with numbers increasing daily (Gulland, 2016). According to the WHO’s public health notice, we should anticipate the expansion of the virus area to include all of the countries in North and South America, excluding Canada and Chile.
The Zika virus is spread by mosquitoes, specifically mosquitos in the Aedes species. These are the same insects that transmit viruses such as yellow fever and dengue (Aggarwal et al, 2016). Originally, when the virus was isolated in Uganda, it was found in the A. albopictus mosquito, which lives deep in the forests and prefers animal over human hosts; therefore, while there were cases of human infection, they were limited and mostly undocumented. The mosquito hosts in Brazil and South America are A. aegypti mosquitoes that prefer human hosts (Center for Disease Control and Prevention, 2016). A. aegypti can be found in all of the countries in North and South America, besides Canada and Chili.
When a mosquito bites a human Zika carrier it becomes a carrier of the virus itself. Then this mosquito transmits the disease to each individual human that it bites thereafter. When these humans are bitten by a different mosquito, that mosquito becomes infected as well; the cycle continues as more humans and greater numbers of mosquitoes are effected. Less common routes of transmission include pregnancy, sexual transmission and possibly blood transfusion (Center for Disease Control and Prevention, 2016). A mother will pass the virus to her unborn child and a man will pass the virus to his partner during sexual intercourse. For these reasons, extra precaution should be taken by pregnant women, women at risk for becoming pregnant and couples trying to conceive.
In most cases, Zika virus symptoms remain relatively mild and asymptomatic, imitating similar flavivirus infections such as dengue and chikingunya. It would be common for a person to be infected, not present any symptoms and remain unaware of their condition. If symptoms present themselves they appear in the form of a headache, fever, rash, conjunctivitis and joint pain (Center for Disease Control and Prevention, 2016). These symptoms appear approximately 3 – 12 days after infection and persist 2 – 7 days in most cases. The majority of Zika patients remain asymptomatic, there have been no cases of hospitalization due to the disease and no virus-related fatalities reported to date (Aggarwal et al, 2016). The virus itself will remain in the blood for up to a week and the individual will likely develop antibodies to protect themselves from future infections.
Although the Zika virus is rather benign in the general population, pregnant women developing the virus may have cause for major concern. Scientists have verified that the virus can, and does, cross the placental barrier from mother to child; therefore, researchers are working on a connection between the Zika virus and recent elevations in fetal malformations in epidemic areas. The Ministry of Health of Brazil reports a 20-fold increase in the incidences of newborn microcephaly, while other complications such as neurologic manifestations and Guillain-Barre syndrome are thought to be connected as well (Mlaka, 2016).
According to the Oxford Dictionary, microcephaly is defined as “abnormal smallness of the head, a congenital condition associated with incomplete brain development.” This rare neurological condition has been documented to occur in only 2 – 12 babies per 10,000 live births in the United States (Center for Disease Control and Prevention, 2016). The dramatic increase in cases found in areas affected with the Zika virus, especially Brazil, leads scientists to believe there is a connection between the two. In the meantime, prevention of the Zika virus is the best method of protection.
Currently, there is not a vaccine for the Zika virus. However, based on information provided by an Indian Biotech company, development of a vaccine is in the preclinical trials stage (Aggarwal et al, 2016). Until such a vaccine is available, the best form of prevention is to prevent mosquito bites. Covering our bodies with clothing, including long sleeves and long pants, using insect repellant, preventing mosquitos from entering our houses with screens and repellants and sleeping under a mosquito net are the best forms of prevention currently. It is also important to consider limiting travel to Zika-infected areas and/or increasing protective measures if travel to these areas is necessary (Aggarwal et al, 2016).
If prevention fails, and an individual is infected with the Zika virus, there are no antiviral treatment drugs available. Action includes symptomatic treatments only. Therapeutic methods include rest, adequate hydration and paracetamol to treat fever and joint pain. Until the exact infection has been determined, aspirin and other non-steroidal anti-inflammatory drugs should be circumvented. In order to prevent the virus cycle from continuing, infected persons should avoid mosquito bites for the first week of infection. The virus is carried in the host’s blood and can be transmitted to additional mosquitoes and consequently more humans (Center for Disease Control and Prevention, 2016).
In conclusion, the Zika virus is a flavivirus that was isolated in Uganda in 1947 and has been causing concern worldwide since its appearance in South America in 2007. Normally rather benign, the Zika virus is asymptomatic is the majority of the population and seems to only cause major concern for pregnant women or couples/women trying to conceive due to fetal anomaly concerns. With the proper research and prevention techniques, the Zika virus will not negatively affect the general population as a whole.
References
Aggarwal, R., Aggarwal, H., Basu, M., & Chugh, P. (2016). Zika virus disease. Int J Community Med Public Health, 1352-1354. http://dx.doi.org/10.18203/2394-6040.ijcmph20161599
Center for Disease Control and Prevention. (2016). Microcephany | CDC. Retrieved 11 June 2016, from Center for Disease Control and Prevention: Microcephany: http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html
Center for Disease Control and Prevention. (2016). Zika Virus | CDC. Retrieved 11 June 2016, from Center for Disease Control and Prevention: Zika Virus: http://www.cdc.gov/zika/index.htm
Gulland, A. (2016). Zika virus is a global public health emergency, declares WHO. BMJ, i657. http://dx.doi.org/10.1136/bmj.i657
Kron, J. (2016). In a Remote Ugandan Lab, Encounters With the Zika Virus and Mosiquitos Decades Ago. The New York Times. Retrieved from http://www.nytimes.com/2016/04/06/world/africa/uganda-zika-forest-mosquitoes.html?_r=0
Mlakar, J., Korva, M., Tul, N., Popović, M., Poljšak-Prijatelj, M., & Mraz, J. et al. (2016). Zika Virus Associated with Microcephaly. New England Journal Of Medicine, 374(10), 951-958. http://dx.doi.org/10.1056/nejmoa1600651
