Zika virus infection has quickly become a hot topic in the news this week. As of this writing, nearly forty cases have been identified here in the U.S. These individuals had recently traveled to a country where the infection has been known to be ongoing. Fortunately, health officials have confirmed that other residents of the states are not at risk of catching the virus from the infected persons.
Zika virus is an emerging mosquito-borne virus that was first identified in Uganda in 1947 in rhesus monkeys. The first human infection was identified in 1952 in Uganda. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia, and the Pacific. The first reported infection in the Western Hemisphere was in May, 2015 in Brazil.
The disease is transmitted to people through the bite of an infected mosquito, mainly in tropical regions. It is the same mosquito that transmits dengue, chikungunya, and yellow fever. These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots and vases. They are aggressive daytime biters, prefer to bite people, and live indoors and outdoors near people. Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites. This is still a question as to whether the virus can be transmitted through blood transfusions.
The incubation period (the time from exposure to symptoms) of the disease is not clear, but is likely to be a few days. The symptoms include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache. These symptoms are usually mild and last for two to seven days.
During large outbreaks in French Polynesia and Brazil in 2013 and 2015 respectively, health authorities reported potential neurological and auto-immune complications of Zika virus disease (Guillain-Barre syndrome). Additionally, health authorities in Brazil have observed a possible link between Zika virus infection and specific birth defects.
Diagnosing the disease is difficult due to the similarity of symptoms to other viral illnesses. Special blood tests to test for antibodies or to isolate the virus can be performed. However, the viruses can cross-react with other like viruses such as dengue, West Nile, and yellow fever.
About one in five people infected with Zika virus become symptomatic. The disease is usually relatively mild and requires no specific treatment. People sick with Zika virus should get plenty of rest, drink enough fluids, and treat pain and fever with common medicines. If symptoms worsen, they should seek medical care and advice. There is currently no vaccine available.
Mosquitoes and their breeding sites pose a significant risk factor for Zika virus infection. Prevention and control relies on reducing mosquitoes through removal and modification of breeding sites and reducing contact between mosquitoes and people.
This can be done by using insect repellent; wearing clothes (preferably light-colored) that cover as much of the body as possible; using physical barriers such as screens, closed doors and windows; and sleeping under mosquito nets. It is also important to empty, clean, or cover containers that can hold water such as buckets and flower pots, so that places where mosquitoes can breed are removed. Special attention and help should be given to those who may not be able to protect themselves adequately, such as young children, the sick or elderly. Travelers should take the basic precautions described above to protect themselves from mosquito bites.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.
