Non-polio Enteroviruses in Karnataka, India: Virological surveillance of acute flaccid paralysis cases (July 1997-2013).

BACKGROUND AND OBJECTIVES: Since 1997 National Institute of Virology, Bangalore Unit involved in WHO's Acute flaccid paralysis paediatric cases surveillance programme to isolate and detect polioviruses. Stool samples yielded not only polioviruses but also Non-Polio enteroviruses. This report is an overview of non-polio Enterovirus (NPEV) epidemiology in Karnataka state, India for the period of 16-years and 6 months from July 1997-2013. METHODS: A total of 19,410 clinical samples were processed for virus isolation as a part of acute flaccid paralysis (AFP) surveillance for Global Polio Eradication Programme in India at National Polio Laboratory, at Bengaluru. NPEV detection was performed by virus isolation on cell culture according to World Health Organisation recommended protocols. RESULTS: A total of 4152 NPEV isolates were obtained. The NPEV isolation rate varied from year to year but with a total NPEV rate of 21.39%. CONCLUSION: A seasonal variation was noted with high transmission period between April and October with peaks in June-July. The male to female ratio was 1:1.2. The isolation of NPEV decreased significantly with the increase in age. Epidemiology of NPEVs from AFP cases in Karnataka is described.

Outbreak of encephalitis in Bellary District of Karnataka & adjoining areas of Andhra Pradesh.

An outbreak of encephalitis in Bellary district of Karnataka state and adjoining areas of Andhra Pradesh which occurred during October 1986 to January, 1987, has been investigated. Out of the 219 patients reported, 110 were from Bellary district and the remaining 109 were from Anantapur and Kurnool districts of Andhra Pradesh; 131 (59.8%) were males and 88 (40.2%) females, while 192 (87.7%) patients were aged 10 yr and below. Sixty one patients died giving a case fatality rate of 27.9 per cent. Virological/serological investigations were carried out on 153 patients. Japanese encephalitis (JE) virus was isolated from the brain tissue of 2 cases. On the basis of the results of serological tests and virus isolation, a flavivirus (JE/WN/DEN) etiology could be established in 116 (75.8%) patients.

Serological evidence for Japanese encephalitis virus and West Nile virus infections in water frequenting and terrestrial wild birds in Kolar District, Karnataka State, India. A retrospective study.

In a serological survey of birds in a Japanese encephalitis (JE) endemic area of Kolar District, Karnataka State, India, 859 bird sera were tested by hemagglutination-inhibition test (HIT) for JE encephalitis and West Nile encephalitis (WNE) viruses. Only 2 (0.002%) and 178 (20.72%) sera were positive for JE virus (JEV) and WNE virus (WNV), respectively. Only 160 (18.63%) of 859 sera could be subjected to neutralizing test (NT). Of these, 20 (12.50%) and 62 (38.75%) were positive for JEV and WNV antibodies, respectively. These findings indicate that bird species such as Pond Herons and Little Egrets among ardeid birds and Grey Partridges and Quails among terrestrial birds are infected with JEV and WNV and play probably a role in the maintenance of these viruses in the abovementioned part of India.

West Nile virus isolates from India: evidence for a distinct genetic lineage.

The complete genomic sequence of one human isolate of West Nile virus (WNV) and the partial genomic sequences of 14 other strains from India isolated in the period 1955-1982 from different hosts and geographical areas were determined. Phylogenetic analyses based on complete and partial genomic sequences (921 nt of the C-prM-E region) revealed that WNV could be classified into five distinct groups that differed from each other by 20-25% at the complete genome level and by 20-26% using partial sequences. Of the Indian isolates, 13 formed a distinct genetic lineage, lineage 5, whereas two isolates, one from a human patient (1967) and another from a bat (1968), were related closely to lineage 1 strains. The complete genomic sequence of the Indian isolate, 804994, showed 20-22% genetic divergence from the previously proposed lineage 1 and 2 strains and 24-25% divergence from isolates of the newly proposed lineages 3 (Rabensburg isolate 97-103 of 1997) and 4 (Russian isolate LEIV-Krnd88-190 of 1998). Similarly, the partial genomic sequences of the Indian isolates showed 21-26% divergence from lineage 1 and 2 strains and from the Rabensburg (97-103) and Russian (LEIV-Krnd88-190) isolates. Cross-neutralization using strain-specific polyclonal antibodies against lineage 1 strain Eg-101 and representative Indian strains suggests substantial antigenic variation. This study documents circulation of WNV strains typical to India for 27 years and the introduction of lineage 1 strains during 1967-1968. These results indicate strongly that WNV should be classified into five genetic lineages, with Indian viruses constituting the distinct genetic lineage 5.

Clinical profile and outcome of Dengue fever cases.

Dengue fever is on rise globally. In India, Dengue epidemics are expanding geographically, even into the rural areas. Dengue can present with varied manifestations. The mortality rate has been brought down with high index of suspicion, strict monitoring and proper fluid resuscitation. Herewith, we are presenting clinical features and outcome of Dengue cases seen in and around Hubli (North Karnataka).

Swine HEV infection in south India and phylogenetic analysis (1985-1999).

Hepatitis E is endemic in India. It was recently noted that although all the Indian human hepatitis E virus (HEV) isolates (1976-2001) were placed in genotype I, the swine HEV recovered from western India (2000) belonged to genotype IV. This was in contrast to reports from the United States and Taiwan wherein both human and swine HEV belonged to the same genotype, i.e., genotypes III and IV, respectively. In order to validate these findings further, we retrospectively examined serum samples collected from pigs from southern India. Sequential serum samples from 45 (1985-1987) and 12 (1999) pigs from Karnataka state, south India, were screened for the presence of HEV RNA (nested PCR) and IgG-anti-HEV (ELISA). PCR products (Open Reading Frame-2 region) were sequenced and subjected to phylogenetic analysis. In this study, 42/45 (1985-1987) and 12/12 (1999) pigs showed seroconversion to IgG anti-HEV antibodies, with a mean age at seroconversion of 4.8 +/- 1.6 months. Four samples collected in 1999 and two samples collected during 1985 were HEV RNA positive. All swine HEV sequences clustered with genotype IV, demonstrating that swine HEV was prevalent among south Indian pigs for at least for 16 years and, similar to western India, belonged to genotype IV. Thus, genotype I and IV HEV continue to circulate in humans and pigs, respectively, from India. Whether swine HEV infects humans remains to be determined.