Zika and West Nile Viruses in Body Fluids: Optimization of RNA Detection for Viral Persistence Studies
Abstract
Zika virus (ZIKV) and West Nile virus (WNV), mosquito-borne flaviviruses, remain a major health concern throughout the world. Although human infections are typically asymptomatic, ZIKV and WNV can result in febrile illness and neurologic disorders or congenital syndrome in severe cases. Detecting infection can be a challenge given that 80% of people with acute infection are asymptomatic, and the window to detect viremia in serum is short. The ability to extend that window is needed in order to detect ZIKV and WNV at later time points after infection. In addition, recent studies supply evidence for chronic conditions related to WNV infections, while other investigations establish the prolonged shedding of ZIKV and WNV RNA in body fluids. Through this dissertation research, RNA extraction methods were evaluated to optimize detection of WNV and ZIKV in various body fluids using rRT-PCR as means of improving the sensitivity of detection. Serially-collected whole blood (WB) and urine (UR) samples from a large cohort of WNV-positive patients were evaluate for the persistence of WNV RNA in WB and UR in association with a review of patient histories in order to identify potential risk factors for chronic WNV systemic infection. ZIKV and WNV RNA recovery methods were optimized for a number of body fluids through spiking experiments. The resultant procedures were used in conjunction with PCR detection to identify WNV-positive WB and UR samples available in the Houston West Nile virus cohort. Ten out of 283 WB samples tested positive for WNV RNA, all collected within 74 days post onset (DPO). Weibull distribution modeling calculated the median time to loss of WNV detection in WB at 69.9 DPO. No associations between patient factors and WNV-positive WB could be found. None of the 288 UR specimens analyzed were WNV-positive, most likely due to RNA degradation during prolonged storage. In addition to introducing more effective extraction methods for the recovery of viral RNA from a variety of biological samples, this investigation provides the most accurate estimates to date for the duration of WNV in the WB of infected patients.
Subject Area
Molecular biology|Virology|Epidemiology
Recommended Citation
Gorchakov, Rodion V, "Zika and West Nile Viruses in Body Fluids: Optimization of RNA Detection for Viral Persistence Studies" (2018). Texas Medical Center Dissertations (via ProQuest). AAI10928080.
https://digitalcommons.library.tmc.edu/dissertations/AAI10928080