While the herpes virus HSV is very common around the world, infection in newborns can be dangerous or fatal. Clinicians therefore need good methods to prevent mother-to-child HSV transmission, which is most likely to occur during childbirth if the mother is shedding virus at the time. The current guidelines for clinical use dictate that if the mother has genital lesions at the time of labor, she should undergo a C-section instead of vaginal delivery. But since herpes shedding often occurs in the absence of lesions, this method has not significantly reduced instances of neonatal herpes in the U.S. Now, VIDD researchers, including joint assistant member Dr. Amalia Magaret, co-director Dr. Larry Corey, and affiliate investigators Drs. Anna Wald and Rhoda Morrow, led by University of Washington Associate Professor Dr. Carolyn Gardella, have devised a method to rapidly test for presence of viral DNA in the genitalia of laboring women, thus quickly identifying HSV positive mothers who are shedding and would benefit from a C-section or prophylactic antiviral treatment to prevent infecting their newborn baby.
The researchers wanted their method to be easy to use with minimal training in the clinic setting, so they prepared kits of reagents for PCR, a sensitive molecular technique to detect specific DNA sequences. They tested the method on more than 400 samples from patients with herpes lesions and from mothers in labor, and optimized the PCR parameters to maximize sensitivity and specificity of the method. Importantly, their technique delivers results in two hours, quickly enough for a laboring woman’s doctor to use the information in her treatment.
Gardella C, Huang ML, Wald A, Magaret A, Selke S, Morrow R, Corey L. Rapid polymerase chain reaction assay to detect herpes simplex virus in the genital tract of women in labor. Obstet Gynecol. 2010 Jun;115(6):1209-16.