Differential Recognition of a Protective Filarial Antigen by Antibodies from Humans with Bancroftian Filariasis

The objectives of this study were to identify filarial antigens which induce enhanced clearance of circulating microfilariae and to establish if human antibody reactivity with these molecules correlates with the apparent parasite burdens of residents of an endemic area of Bancroftian filariasis. Mice immunized with an extract of Brugia malayi microfilariae develop IgG antibodies to four major filarial antigens with an apparent molecular weight (Mr) of-112,000, 60,000, 45,000, and 25,000. Animals immunized with gel slices containing the- 25,000-M, antigen are resistant to intravenous challenge with live microfilariae (78-98 % reduction in parasitemia vs. controls, P < 0.01). A group of 22 amicrofilaremic humans had a significantly higher (P < 0.025) mean antibody titer to the M, 25,000-M, antigen (1: 424) than 16 microfilaremic individuals (1:95). There were no significant differences between the two groups in antibody titers to filarial antigens of M,-112,000, 60,000, and 45,000 Mr. These data suggest that a high degree of reactivity to the 25,000-Mr antigen in humans with lymphatic filariasis correlates with a parasitologic status that is least conducive to transmission of infection

High prevalence of rotavirus infection among neonates born at hospitals in Delhi, India: predisposition of newborns for infection with unusual rotavirus

Although rotavirus is the most common cause of diarrhea in children older than 3 months of age, neonatal infections, which are asymptomatic, have rarely been surveyed and have been identified in only a few discrete nosocomial outbreaks. After such a nosocomial outbreak of rotavirus infection among newborns at a hospital in Delhi, we screened infants born at five other nurseries in the immediate area to assess the prevalence of neonatal infections and to determine whether the unique neonatal rotavirus strain, 116E, previously identified in Delhi, was present in other settings. Infection was documented in 43 to 78% of hospitalized infants between 4 and 6 days of life born at five of the six hospitals. Infection with strains related to 116E were the most common, but other unusual strains and no strains common in the community were detected. In addition a shift in genotype was observed among specimens collected from two of these hospitals during a 2-year period. Our observation that neonatal rotavirus infections are more common than recognized previously would encourage the administration of rotavirus vaccines during the newborn period and suggests that the low efficacy of vaccines observed during trials in developing countries may be caused by early natural exposure of infants before immunization. The extraordinary predisposition of neonates for unusual rotavirus strains not commonly found in the community should encourage others to screen neonates for this infection, characterize the strains more fully and attempt to understand at a molecular level the unique relationship between the infecting strain type and the age of the host