Lab Matters Fall 2016 - Page 22

infectious diseases Dr. Patrick Bryant, Wadsworth Center Virology Laboratory Wadsworth Center Virology Laboratory Identifies Large Mumps Outbreak in Nassau County, NY by Patrick Bryant, PhD, research scientist, New York State Department of Health and Kirsten St. George, PhD, chief of viral diseases, New York State Department of Health Mumps is a vaccine preventable, viral illness caused by a member of the family Paramyxoviridae, genus Rubulavirus. Mumps usually involves pain, tenderness and swelling in one or both parotid salivary glands. Despite the ready availability of a vaccine, mumps activity in the United States has begun to surge over the past decade, with one of the largest outbreaks in 20 years occurring in 2006. Since then, numerous outbreaks have occurred in the United States, particularly in young adults in their 20s and 30s. I n its role as one of four APHL-funded viral Vaccine Preventable Diseases (VPD) Reference Centers, the Virology Laboratory at the Wadsworth Center identified a large mumps outbreak this year in Nassau County, NY. During the outbreak, the laboratory received buccal swab samples from the middle of May into September that were collected from individuals with parotitis. Samples from 116 suspected mumps cases in Nassau County were tested and 34 were confirmed positive by mumps rRT-PCR. Of particular note, several symptomatic cases occurred in patients who had previously received two doses of the MMR vaccine in accordance with recommended dosing and 20 LAB MATTERS Fall 2016 scheduling. Ongoing research suggests evidence of waning immunity as well as possible antigenic differences between the currently circulating strain and the vaccine. As with all viruses detected by the reference laboratory, the positive samples were genotyped by Sanger sequencing of the SH gene. All were found to be genotype G including the index case—a student who attended Harvard University during a campus mumps outbreak and returned to Nassau County following graduation. Mumps genotype G has also been the cause of the other recent outbreaks in the US. As of September 10, 44 states were reporting some level of mumps activity. Testing of new cases is ongoing to determine if the mump