ABSTRACT
The emergence of Zika virus in the Americas has caused an increase of babies born with microcephaly or other neurological malformations. The differential diagnosis of Zika infection, particularly serological diagnosis, is an important but complex issue. In this study, we describe clinical manifestations of 94 suspected cases of congenital Zika from Bahia state, Brazil, and the results of serological tests performed on children and/or their mothers at an average of 71 days after birth. Anti-Zika immunoglobulin M (IgM) antibodies were detected in 44.4% and in 7.1% of samples from mothers and children, respectively. Nearly all the IgM, and 92% of immunoglobulin G positive results were confirmed by neutralization test. Zika specific neutralizing antibodies were detected in as much as 90.4% of the cases. Moreover, dengue specific neutralizing antibodies were detected in 79.0% of Zika seropositive mothers. In conclusion, Zika IgM negative results should be considered with caution, due to a possible rapid loss of sensitivity after birth, while the NS1-based Zika IgM enzyme-linked immunosorbent assay test we have used has demonstrated to be highly specific. In a high percentage of cases, Zika specific neutralizing antibodies were detected, which are indicative of a past Zika infection, probably occurred during pregnancy in this population.
Subject(s)
Infectious Disease Transmission, Vertical/statistics & numerical data , Zika Virus Infection/epidemiology , Zika Virus Infection/transmission , Zika Virus , Adult , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Brazil/epidemiology , Child, Preschool , Diagnostic Imaging , Humans , Immunoglobulin M/blood , Infant , Infant, Newborn , Neutralization Tests , Phenotype , Public Health Surveillance , Serologic Tests , Zika Virus Infection/diagnosisABSTRACT
To determine the seroprevalence of antibodies against dengue virus (DENV) and West Nile virus (WNV) in the human population of the Bolivian Chaco, we tested 256 inhabitants of two rural communities. The seroprevalence, confirmed by plaque reduction neutralization test, was 7.8% and 2.7% for DENV and WNV, respectively.
Subject(s)
Antibodies, Viral/blood , Dengue Virus/immunology , Dengue/epidemiology , West Nile Fever/epidemiology , West Nile virus/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Bolivia/epidemiology , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Infant , Male , Middle Aged , Neutralization Tests , Rural Population , Seroepidemiologic Studies , Viral Plaque Assay , Young AdultABSTRACT
In the last few years, several imported cases of Zika virus (ZIKV) infection were reported in European countries. We report the first imported ZIKV infection case in a Croatian traveler returning from Brazil. The patient presented with a low-grade fever, pruritic rash, general weakness, myalgia, arthralgia and edema of the legs and recovered completely within a week. ZIKV infection was confirmed by detection of IgM/IgG antibodies using enzyme-linked immunosorbent assay (ELISA) and confirmed by plaque-reduction neutralization test (PRNT). ZIKV IgM antibodies cross-reacted with dengue virus (DENV), West Nile virus (WNV) and tick-borne encephalitis virus (TBEV) in ELISA. In indirect immunofluorescence assay (IFA), IgM cross-reactivity was found only with DENV-3. ZIKV IgG antibodies cross-reacted with DENV in both ELISA and IFA. PRNT for DENV was negative. Control serology performed on days 64 and 98 after disease onset showed a decline in cross-reactive heterologous DENV IgG antibodies compared to persistently high titer of homologous ZIKV IgG antibodies.