Louisville Medicine Volume 63, Issue 11 | Page 8

ZIKA VIRUS – GUIDANCE FOR PHYSICIANS Sarah Moyer MD, MPH, and Katherine Pohlgeers, MD, MS Z ika virus is suspected in the precipitous rise in cases of microcephaly in newborns in Brazil and other areas of South and Central America. On March 9, the Centers for Disease Control and Prevention (CDC) confirmed a case of Zika in a Jefferson County man who became infected on a trip to Central America. The man has made a full recovery. There have also been cases reported in the neighboring states of Indiana and Tennessee. All U.S. cases were either among individuals who had traveled to a Zika infected area or who had been infected by sexual contact with an individual who had contracted the virus in an infected region. On February 22, the CDC deployed a 16-member team of epidemiologists to Brazil and began training dozens of Brazilian teams as part of a case control study to determine whether the Zika virus is the cause of the upsurge in cases of microcephaly throughout the country and the region. CDC formed eight teams of American and Brazilian investigators who fanned out into the region of Joao Pessoa in northeastern Brazil searching for about 100 mothers who gave birth to babies with microcephaly since the Zika outbreak began. Investigators hoped that this study would either provide more definitive evidence establishing the link between Zika and microcephaly or identify other factors that may be to blame, either in combination with Zika or instead of Zika. Zika virus is a mosquito-borne flavivirus primarily transmitted by Aedes mosquitoes, the same mosquitoes that spread Chikungunya 6 LOUISVILLE MEDICINE and dengue. Infected mosquitoes can then spread the virus to other people through bites. It can also be transmitted from a pregnant mother to her fetus during pregnancy or around the time of birth. To date, there are no reports of infants getting Zika virus through breastfeeding. Because of the benefits of breastfeeding, mothers are encouraged to breastfeed even in areas where Zika virus is found. Sexual transmission of Zika virus can also occur, although there is limited data about the risk. Given the potential risks of maternal Zika virus infection, pregnant women whose male partners have or are at risk for Zika virus infection should consider using condoms or abstaining from sex. An estimated 80 percent of persons infected with Zika virus are asymptomatic. Symptomatic disease is generally mild. The most common symptoms of Zika virus include fever, rash, joint pain or conjunctivitis. Symptoms typically begin two to seven days after being bitten by an infected mosquito. Severe disease requiring hospitalization is uncommon, and fatalities are rare. Once a person has been infected, he or she is likely to be protected from future infections. The concern is that Zika infection during pregnancy may be linked to serious birth defects, notably microcephaly – a condition in which the baby is born with an abnormally small head. Babies with microcephaly can have a range of other problems, depending on how severe their microcephaly is. Microcephaly has been linked with seizures, developmental delay, intellectual disability, problems with movement and balance, difficulty swallowing, hearing loss and vision problems. There have also been cases of Guillain-Barré syndrome reported in patients following suspected Zika virus infection. The relationship between Zika virus infection and Guillain-Barré syndrome is being investigated.