Serologic Surveillance for West Nile Virus and Other Flaviviruses in Febrile Patients, Encephalitic Patients, and Asymptomatic Blood Donors in Northern Mexico

Abstract

A clinical and serological investigation was performed to determine the presence of West Nile virus (WNV) among febrile and encephalitic patients in northern Mexico. In addition, asymptomatic blood donors were serologically assayed for WNV to determine the seroprevalence of WNV in the general population. The study cohort consisted of 1432 individuals (588 febrile patients, 44 encephalitic patients, and 800 asymptomatic blood donors). All subjects were negative for WNV IgM. Sixty subjects were reactive for dengue virus (DENV) IgM (16 blood donors and 44 febrile patients). A subset (n ¼ 425) of individuals was also screened by ELISA for flavivirus IgG. The prevalence of flavivirus IgG in febrile patients, encephalitic patients, and blood donors ranged from 40% to 59%. A subset (n ¼ 147) of sera reactive for flavivirus IgG was further tested by plaque reduction neutralization test. Six individuals with no history of travel during the preceding 12 months were seropositive for WNV. Another 65 individuals were seropositive for DENV1 and 24 were seropositive for DENV2. The high prevalence of dengue antibodies in northern Mexico appears to limit the incidence of WNV infection in this region.Article Summary Line: Antibodies to WNV, DENV-1, and DENV-2 were identified in humans in northern Mexico.

Poorly Neutralizing Cross-Reactive Antibodies against the Fusion Loop of West Nile Virus Envelope Protein ProtectIn Vivovia Fcγ Receptor and Complement-Dependent Effector Mechanisms

“…While further epidemiologic studies are warranted, widespread exposure to DENV and other endemic flaviviruses in tropical Central and South America could result in production of polyclonal DII-FL-specific antibodies that fail to neutralize WNV infection by conventional PRNT analysis but still protect humans in vivo, and thus contribute to the lack of severe cases of human WNV infection in this region. Indeed, one recent serological surveillance study in Mexico supports this hypothesis (63).…”

Orthobunyaviruses, a Common Cause of Infection of Livestock in the Yucatan Peninsula of Mexico

“…High antibody titers are often reported in flavivirus serologic investigations performed in geographic areas where multiple flaviviruses circulate and have been attributed to exposure to two or more flaviviruses. [52][53][54] For example, all four dengue flaviviruses are present in Mexico and patients in this region often have high PRNT titers to all serotypes. 53 It seems likely that the aforementioned horses and sheep had infections with at least two orthobunyaviruses and that the responses we detected may have been anamnestic responses.…”

“…[52][53][54] For example, all four dengue flaviviruses are present in Mexico and patients in this region often have high PRNT titers to all serotypes. 53 It seems likely that the aforementioned horses and sheep had infections with at least two orthobunyaviruses and that the responses we detected may have been anamnestic responses. In this regard, Blackmore and Grimstad reported high neutralizing antibody titers to CVV in white-tailed deer experimentally inoculated with CVV, then POTV.…”

Generation of a recombinant West Nile virus stably expressing the Gaussia luciferase for neutralization assay

“…Since it was recognized in New York City in 1999, WNV has rapidly spread across the North American continent, resulting in continuous epidemics in the United States, Canada, and Mexico (Chung et al, 2013;Deardorff et al, 2006;Lindsey et al, 2010;Mann et al, 2013;Rodriguez Mde et al, 2010). With the recent identification of WNV-infected cases and the subsequent isolation of this virus from mosquitoes in Kashi region, Xinjiang, China (Lu et al, 2014), WNV has become an important emerging virus in China.…”