Oral fluid, a substitute for serum to monitor measles IgG antibody.

We have analyzed the suitability and potential of Oral Fluid (OF) to substitute serum in estimating measles IgG antibodies, during community surveys, by comparing the Optical Density (OD) of measles IgG antibodies in OF and serum of 100 apparently asymptomatic children. IgG antibody status was determined using commercially available - Measles IgG Capture ELISA. Sensitivity 89.5%, specificity 90.6% Concordance of 89%, coefficient of correlation r is equal to 0.97 (Karl Pearson's) and rho is equal to 0.86 (Spearman's), was found between OD value of OF and serum. The study emphasizes the potential of OF to surrogate serum in estimating Measles IgG antibody among children. The OF collection is advantageous over blood as it is painless. It is suitable for non-technical staff, easy to transport and less bio-hazardous.

Isolation of measles virus from cerebrospinal fluid of children with acute encephalopathy without rash.

OBJECTIVE: To determine the viral agent involved in cases of acute encephalopathy in children during an outbreak in Northern India. DESIGN: Virological and serological studies using serum and cerebrospinal fluid specimens from patients. METHODS: Serum and CSF specimens were tested by IgM ELISA for IgM antibodies to variety of viruses like Japanese encephalitis, West Nile, Dengue and Measles. The specimens were inoculated into Vero cell monolayer for virus isolation. The viral strains isolated were identified by indirect immunofluorescence test and qualitative in-vitro neutralization test using polyclonal and monoclonal antibodies to measles. Identity of the isolates was reconfirmed using RT-PCR method. RESULTS: Of the 28 specimens tested, 17 had IgM antibodies to measles. Commercial IgM ELISA kits confirmed the serological findings. Vero cell cultures yielded 4 isolates from CSF and 2 from serum specimens of six different patients. Cytopathic effect was typical of measles. Indirect imunofluorescence using polyclonal and monoclonal antibodies to measles HA protein, confirmed the measles etiology. Neutralization tests reconfirmed the measles strain isolation. RT-PCR amplified product was confirmed as measles. CONCLUSION: The isolation of measles virus from CSF and serum of children with acute encephalopathy without rash proved the etiological role of measles virus in this outbreak.

Exposure of Indian children to hepatitis A virus & vaccination age.

It is known that 90 per cent of children in India are exposed to hepatitis A virus (HAV) by the age of six years. The aim of the study was to determine when in early childhood maximum HAV infections take place and to deduce an appropriate age for vaccination against HAV. Blood samples of 499 children between the ages of three days and six years were collected and tested for the presence of antibodies against hepatitis A. A statistically significant negative correlation between IgG anti-HAV and age was observed (P < 0.01) up to 11.67 months when IgG anti-HAV positivity was found to be minimum (9.25%). Subsequently a significant positive correlation was noted (P < 0.01). Exposure to HAV was 28.9 per cent soon after the waning of maternal antibodies in the 13-15 month age group which increased to 52.5 per cent by two years of age and 90.9 per cent by 6 yr. It is concluded that in addition to other preventive measures, if children in India are to be vaccinated against hepatitis A they should be immunised against HAV by 9-10 months of age when the maternal antibodies disappear.

IgG & IgM antibodies against measles virus in unvaccinated infants from Pune: evidence for subclinical infections.

IgG and IgM class of antibodies to measles virus were estimated in the plasma samples of 211 unvaccinated infants living under overcrowded conditions in Pune, Maharashtra. IgG antibodies to measles virus, in high titres, were detected in 52.1 per cent and IgM antibodies in 31.3 per cent of the infants studied. Most of the infants with IgM antibodies to measles virus had not suffered from an attack of measles. A history of contact with an older child with overt measles was available for 13.3 per cent of the 211 infants studied. Among these infants with such a contact history, 82.1 per cent had IgM antibodies to measles virus. These observations suggest that many infants studied by us, had experienced subclinical measles infections and many times older children with measles at home or in the neighbourhood might have transmitted such infections.

Serological studies on subacute sclerosing panencephalitis.

This study reports the clinical picture and measles virus antibody titres in 32 patients with cases of suspected subacute sclerosing panencephalitis (SSPE). The history of myoclonic jerks, mental regression, inability to walk and slurred speech, were noted in these cases. The EEG showed generalised periodic complexes in twenty nine patients and only in three patients the EEG was not available. In all the above mentioned patients measles occurred at an early age (within a year).

Localization of arboviral antigen in brain tissues from patients with encephalitis.

Brain tissues from 38 patients with a clinical suspicion of encephalitis or encephalopathy were examined by two immunoenzymatic techniques for the detection of arboviral antigen. Group B arboviral antigen was identified in 23 of these tissues. This simple method could be used for the diagnosis of the causal agent of encephalitis.