Norovirus-associated gastroenteritis, Pernambuco, Northeast Brazil, 2014-2017.

Norovirus (NoV) is currently the leading cause of nonbacterial gastroenteritis. In Brazil, few studies have characterized the molecular, epidemiological and clinical features of NoV-associated gastroenteritis. This study aimed to describe the molecular and clinicoepidemiological findings of NoV infections in patients of all ages throughout Pernambuco state, Northeast Brazil. Thus, 1135 stool samples were analyzed from patients with gastroenteritis from Pernambuco state. NoV was detected by enzyme immunoassay in 125 (11.01%) samples. Regarding gender distribution, 55 (44.00%) patients were female and 70 (56.00%) male. Their ages ranged from 5 days to 87 years, and the group most affected by NoV infection (88.00%) was children under 3 years. Complete clinical information was available for 88 out of 125 NoV-positive patients. Diarrhea was present in all patients and vomiting was reported in 60 patients (68.68%). Nine patients (10.22%) had bloody stools and 46 (52.27%) had a fever, with temperatures ranging from 37.90°C to 39.90°C (mean 38.20°C). NoV was detected mainly in the summer-autumn seasons. Genome sequencing and phylogenetic analyses identified four different NoV GII genotypes circulating in this area of the country. Therefore, our study provided valuable information about the clinics and epidemiology of NoV infection in tropical settings and will assist health authorities to develop better control strategies against this important pathogen.

Results of a Zika Virus (ZIKV) Immunoglobulin M-Specific Diagnostic Assay Are Highly Correlated With Detection of Neutralizing Anti-ZIKV Antibodies in Neonates With Congenital Disease.

BACKGROUND: Usually, immunoglobulin M (IgM) serologic analysis is not sufficiently specific to confirm Zika virus (ZIKV) infection. However, since IgM does not cross the placenta, it may be a good marker of infection in neonates. METHODS: We tested blood from 42 mothers and neonates with microcephaly and collected cerebrospinal fluid (CSF) specimens from 30 neonates. Molecular assays were performed for detection of ZIKV, dengue virus, and chikungunya virus; IgM enzyme-linked immunosorbent assays and plaque-reduction neutralization tests (PRNTs) were performed to detect ZIKV and dengue virus. No control neonates without microcephaly were evaluated. RESULTS: Among neonates, all 42 tested positive for ZIKV IgM: 38 of 42 serum specimens (90.5%) were positive, whereas 30 of 30 CSF specimens (100%) were positive. ZIKV IgM-specific ELISA ratios, calculated as the mean optical density (OD) of the test sample when reacted on viral antigen divided by the mean OD of the negative control when reacted with viral antigen, were higher in CSF specimens (median, 14.9 [range, 9.3-16.4]) than in serum (median, 8.9 [range, 2.1-20.6]; P = .0003). All ZIKV IgM-positive results among the neonates were confirmed by the detection of neutralizing antibodies. Mother/neonate pairs with primary ZIKV infection had neutralizing antibodies to ZIKV only, and mother/neonate pairs with ZIKV virus infection secondary to infection with another flavivirus had high titers of neutralizing antibodies to ZIKV. Among secondary infections, median titers in serum were 2072 (range, 232-12 980) for mothers and 2730 (range, 398-12 980) for neonates (P < .0001), and the median titer in CSF was 93 (range, 40-578) among neonates (P < .0001). CONCLUSIONS: Among neonates, detection of ZIKV IgM in serum is confirmatory of congenital ZIKV infection, and detection of ZIKV IgM in CSF is confirmatory of neurologic infection. Therefore, we recommend testing for ZIKV IgM in neonates suspected of having congenital ZIKV infection and performance of PRNTs in equivocal cases.