Rapid spread of Chikungunya virus infection in Orissa: India.

Background & objectives : A large number of cases of undiagnosed fever and joint pain were reported from different parts of the State of Orissa since February 2006. Epidemiological and laboratory investigation were carried out to confirm the cause of emerging illness, which was provisionally suspected as Chikungunya (CHIK) fever. Methods: Upon getting the reports of suspected CHIK like illness in different parts of the State, epidemic investigations were carried out in the outbreak affected villages. Case history was recorded, clinical examination undertaken and blood samples collected for seroconfirmation for CHIK IgM antibody using ELISA based kit. Simultaneously vector survey was also carried out. Results: With no previous record of CHIK infection in the State, the first outbreak was confirmed during February 2006. Subsequently, the infection spread to 13 of 30 districts in different episodes covering 79 villages till November 2007. Attack rate was 9-43 per cent in the different outbreaks with average seropositivity of 24 per cent to CHIK specific IgM. Morbidity was high though no deaths were recorded. Aedes aegypti and Ae. albopictus were identified as the possible vectors for transmission. Interpretation & conclusions : The report confirmed emergence of CHIK infection in the State of Orissa, India, and its spread to a larger geographic zone in a short period which warrants public health measures to control further spread.

Efforts in diagnosing early leprosy using serological techniques.

Skin scrapings obtained from the lesions of leprosy patients of all types showed 96% positivity to the serum antibody competition test using monoclonal antibody (ML04)to 35 kDa antigen of Mycobacterium leprae. Further, in vitro culture of full thickness skin biopsies from lepromatous patients were noted to release IgG antibodies to M. leprae with a peak antibody response at 48 h. The significance of this local antibody response to Μ. leprae in skin has been discussed for its possible use in diagnosing early leprosy.

Age-related prevalence of antibodies to infective-larvae of Wuchereria bancrofit in normal individuals from a filaria-endemic region.

Antibody isotypic levels (IgM, IgE and IgG subclasses) to infective larvae (L3) of Wuchereria bancrofti were measured in 104 normal individuals from a filaria-endemic region in Orissa. The titres of antibodies were considerably higher in adults (n = 25, 25·1 ± 3·8 year) than in children (n = 52, 7·1 ± 2·1 year). Young children (n = 14) less than four years were seronegative to all isotypes other than IgM, the sero-conversion to which was achieved in the children (n=15) by the age of 7·5±1·2 years. The prevalence of other isotypes increased with age and reached a maximum in early adulthood (18·6 ± 1·6 years), which persisted in older adults (> 30 years). However, the increase in IgG3 prevalence with age was less marked. IgG2 was detected only after 10 years of age. Compared to the high prevalence (100%) of IgM, IgE, IgG1, and IgG2, in adults. IgG3 and IgG4 prevalences were low, 35% and 28% respectively. IgA level to L3 antigen was found to be extremely low even in adults. These data indicate that the prevalence of L3 antibodies was different for different isotypes and the acquisition of antibody response essentially followed an age dependent pattern.

Dextran sulfate induced suppression of Plasmodium berghei parasitaemia.

Effect of dextran sulfate (DS, Mr 500,000) on parasitaemia in mice (Balb/c) infected with erythrocytic stage of P. berghei was investigated. Intraperitoneal injection of DS caused marked suppression of patent parasitaemia and also enhanced the survival time of the infected animals.

Stimulation by adjuvants of cell-mediated immune response in Plasmodium berghei infected mice.

Immunological adjuvants (alum, liposomes and saponin) were utilized to stimulate cell-mediated immune response in Plasmodium berghei infected Balb/c mice. It was shown that malaria antigen mixed with adjuvant induced appreciably delayed type hypersensitivity and production of migration inhibition factor compared to antigen alone.