siga

Background: Norovirus is a leading cause of acute gastroenteritis worldwide. Routine norovirus diagnosis requires stool collection. The goal of this study was to develop and validate a noninvasive method to diagnose norovirus to complement stool diagnostics and to facilitate studies on transmission.

Methods: A multiplex immunoassay to measure salivary immunoglobulin G (IgG) responses to 5 common norovirus genotypes (GI.1, GII.2, GII.4, GII.6, and GII.17) was developed. The assay was validated using acute and convalescent saliva samples collected from Peruvian children <5 years of age with polymerase chain reaction (PCR)-diagnosed norovirus infections (n = 175) and controls (n = 32). The assay sensitivity and specificity were calculated to determine infection status based on fold rise of salivary norovirus genotype-specific IgG using norovirus genotype from stool as reference.

Results: The salivary assay detected recent norovirus infections and correctly assigned the infecting genotype. Sensitivity was 71% and specificity was 96% across the evaluated genotypes compared to PCR-diagnosed norovirus infection.

Conclusions: This saliva-based assay will be a useful tool to monitor norovirus transmission in high-risk settings such as daycare centers or hospitals. Cross-reactivity is limited between the tested genotypes, which represent the most commonly circulating genotypes.

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Background:

AIMS: Secretory Immunoglobulin A (SIgA) plays a critical role in immune functioning by preventing pathogens from adhering to epithelial mucosa. Most infectious agents enter the body via mucosal surfaces, thus SIgA serves in the defense against respiratory, intestinal, and urinogenitary infections, as well as periodontal disease and caries. This study examined the possibility that pre- and postnatal exposure to cigarette and cannabis is associated with individual differences in Secretory Immunoglobulin A (SIgA) levels in early childhood.
METHODS: Participants were 50 mother/infant (29 boys; 35% Caucasian) dyads recruited at their first prenatal appointment in a large northeastern community hospital in the United States. Repeated assessments of pre- and postnatal cigarette and cannabis were conducted beginning in the first trimester of pregnancy, using multiple methods (i.e., saliva, meconium, self-report). Infants were grouped into those prenatally exposed to either cigarette only (n = 19), cigarette and cannabis (n = 19), or with no prenatal substance exposure (n = 12). At age 5 years, the children’s saliva was collected and assayed for SIgA.
RESULTS: There were group differences in SIgA levels as a function of prenatal exposure to cigarette and cannabis – children in the cigarette only and the cigarette and cannabis groups had higher SIgA levels compared to the non-exposed children. Children who experienced the combination of postnatal exposure to cigarette and cannabis had higher levels of SIgA, even after accounting for prenatal exposures and other covariates relevant to immune system functioning.
CONCLUSIONS: Prenatal and postnatal exposure to cigarette and cannabis may be associated with hyperactivity of mucosal immunity in early childhood. Links between cigarette and cannabis exposure and health problems in early childhood may be partially explained by prenatal and postnatal exposure-related changes in mucosal immunity.

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Minimally Invasive Saliva Testing to Monitor Norovirus Infection in Community Settings

Prenatal and postnatal cigarette and cannabis exposure: Effects on Secretory Immunoglobulin A in early childhood.