Yellow fever vaccine has been shown to be efficient in preventing infections, however, recent YFV epidemic in Southeast Brazil demands better understanding on the transmission dynamics and disease distribution in general population. Recent studies have demonstrated an increase in dengue-associated deaths in the last decade. Arboviruses such as DENV and YFV have been endemic in Brazil, while YFV is endemic/enzootic for centuries being introduced during the slave traffic, DENV is more recently in the country and endemic just to four decades. These pathogens have not only been associated with morbidity and mortality, but also with additional health care cost. During the last decade, Brazil has endured zika virus (ZIKV), chikungunya virus (CHIKV), and yellow fever virus (YFV) epidemics. Ecological and epidemiological conditions in Manaus makes its population susceptible for further arbovirus outbreaks hence functional vector control program and febrile-syndrome surveillance are essential to identify unforeseen epidemiological threats.Įmerging arboviruses are a growing health problem in Brazil and worldwide. Taken together, we observed a high prevalence of DENV in the Manaus-Amazon region and a varying degree of serological reactivity against emerging viruses. Live virus neutralization test with ZIKV confirmed that dengue serogroup and ZIKV-spondweni serogroup are distant and DENV-positive individuals do not cross-neutralize ZIKV efficiently. DENV positive individuals with high antibody titers in HIA or envelope protein domain III (EDIII)-ELISA reacted strongly with ZIKV, whereas individuals with low anti-DENV antibody titers reacted poorly towards ZIKV. Overall, 93.7% of participants were seropositive (419/447) for at least one DENV serotype and the DENV seropositivity ranged between 84.8% and 91.0% as determined by HIA. 74.52% of participants were IgG positive (310/416) as estimated by lateral flow tests. Next, we assessed antibody cross-reactivity of DENV-positive individuals with ZIKV using hemagglutination inhibition assay (HIA), purified envelope proteins in an ELISA, and live virus neutralization test. In this study, we estimated the seropositivity rates of nine different Flavivirus es among residents of Manaus city in Brazil. ![]() Pre-existing immunity to one virus can modulate the response to a heterologous virus however, the serological cross-reaction between these emerging viruses in DENV endemic region are poorly understood. Several of these Flavivirus es can co-circulate recently, Zika virus (ZIKV) is becoming increasingly prevalent in Dengue virus (DENV) endemic regions. Flaviviruses are vector-borne positive sense RNA viruses with enormous potential to cause a spectrum of severe diseases in naïve populations and long-term public health impact.
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