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B L Rao

Publications and source records attributed to B L Rao.

At least 19 recordsLinked to original sources
PubMed2001

Seroepidemiology of influenza in Pune, India.

BACKGROUND & OBJECTIVES: Influenza viruses cause frequent epidemics and periodic pandemics throughout the world due to antigenic variations. Serological data can be useful to determine the disease burden and population immunity and for predicting the likelihood of occurrence and potential severity of subsequent epidemics. We undertook a serological analysis of antibodies against ten influenza virus strains in Pune, India. METHODS: Haemagglutination inhibition (HI) test was done on 619 sera collected between 1997-99 during an age-stratified serosurvey in Pune, India against 10 strains of influenza virus. Overall prevalence and spectrum of HI antibodies against these strains was determined. RESULTS: Antibodies to at least one influenza virus strain was seen in 62 per cent (116/188) of the sera from individuals in the age group 5-15 yr, 77 per cent (85/111) in sera from 16-25 yr, 78 per cent (93/119) from 26-35 yr, 84 per cent (77/92) from 36-45 yr and 93 per cent (101/109) in sera from individuals aged > 45 yr. The antibody spectrum progressively increased with age. Antibodies to the pandemic strain A(H2N2) were absent in the age groups < 25 yr. INTERPRETATION & CONCLUSION: The results indicate that influenza virus infection occurs in a large proportion of individuals in our community and may be responsible for a considerable amount of morbidity and mortality. The study also demonstrates the absence of antibody to A/Singapore/1/57 (H2N2) strain in younger persons < 25 yr of age. The potential of its reintroduction cannot be ruled out as H2 variants are circulating in wild birds and population immunity in humans is decreasing.

Adolescent↗
PubMed2001

Isolation of recent variant influenza types A(H3N2), A (H1N1) & B strains in Pune, India.

A total of 293 patients with influenza like illness were investigated during the course of continuous surveillance on influenza in Pune, India in 2000. The throat/nasal swab specimens collected from these patients were inoculated in MDCK cell culture and influenza types A(H3N2), A(H1N1) and type B strains were isolated. They were identified as similar to the recently prevalent variant strains; A/Sydney/05/97(H3N2), A/New Caledonia/20/99(H1N1) and B/Sichuan/379/99. The latter two were the new variant strains reported for the first time in Pune. It is important to note that A(H1N1) strains were isolated in Pune during 2000 after a gap of 10 yr.

Animals↗
PubMed2000

Isolation of recent variant influenza types A (H3N2) & B strains in Pune, India during 1998.

A total of 456 patients with influenza like illness were investigated during the course of continuous surveillance on influenza in Pune, India in 1998. The throat and nasal swab specimens collected from these patients were processed in MDCK cell culture. Influenza type A (H3N2) and type B strains were isolated in MDCK cell culture. They were identified as similar to the recently prevalent globally circulating variant strains; A/Sydney/05/97 (H3N2) and B/Harbin/07/94.

Animals↗
PubMed1998

Strain analysis and epitope mapping of West Nile virus using monoclonal antibodies.

Monoclonal antibodies (MAbs) against an Indian strain (804994) and an Egyptian strain (E 101) of West Nile virus (WNV) were prepared in mice. Nine MAbs against the 804994 strain and 5 MAbs against E 101 strain were obtained. All 14 MAbs reacted with the envelope (E) protein of WNV in an immunoblot assay. They were tested by an enzyme-linked immunosorbent assay (ELISA) for their cross-reactivity with WNV, Japanese encephalitis virus (JEV) and Dengue-2 virus (DEN-2), and for their reactivity in haemagglutination-inhibition (HAI) test. Based on these results MAbs were broadly grouped into three groups, namely WNV-specific HAI-positive, WNV-JEV cross-reactive HAI-positive, and WNV-JEV cross-reactive HAI-negative MAbs. The antigenic cross-reactivity between twelve WNV strains isolated from different geographical regions and their respective hosts was assessed using these MAbs in HAI and complement fixation (CF) tests. The strain analysis by CF distinguished Indian from South African strains. However, a similarity between some Indian and South African strains in HAI was observed. E 101 strain appeared to have antigenic similarity with Indian as well as South African strains. Overall it appears that antigenically similar strains of WNV are prevalent in India. A single heterogenous domain was apparent on the epitope map of WNV deduced by ELISA additivity test.

Animals↗
PubMed1993

Influenza surveillance in Pune, India, 1978-90.

Continuous surveillance of influenza was carried out in Pune between 1978 and 1990. Most of the cases were identified during investigation of 16 outbreaks of influenza in Pune over this period. The majority of cases were children. Ten of the outbreaks occurred during rainy seasons. A total of 290 isolates consisting of several antigenic variants of influenza type A (H3N2), type A (H1N1), and type B viruses were isolated from throat/nasal swabs that were processed in chick embryos and MDCK cell culture and identified using the haemagglutination inhibition test. These variants circulated every year or in alternate years. Nearly two-thirds of the influenza virus isolates (181 out of 290) were from children aged < 10 years. Seasonal analysis indicated that the highest number of isolates (174) were collected during the rainy months of July, August and September, with the maximum number (93) in July.

Adolescent↗
PubMed1991

Characterization of the genome of rice tungro bacilliform virus: comparison with Commelina yellow mottle virus and caulimoviruses.

Rice tungro disease is caused by an infection of two different viruses, rice tungro spherical virus (a (+) sense RNA virus) and rice tungro bacilliform virus (RTBV) with a genome of circular double-stranded DNA. The genome of an RTBV isolate from the Philippines was cloned, sequenced, and found to be 8000 bp in length. It contains four open reading frames (ORFs) on a single strand, with ORF 1 having an internal termination codon (TAA). The 5' and 3' ends of a polyadenylated viral RNA transcript, of genome length, were mapped by primer extension and cDNA sequence analysis, respectively. The transcript is terminally redundant by 265-268 nucleotides. Purified virus particles contain two major proteins with molecular masses of 37 and 33 kDa, although only the 37-kDa protein was detected in the infected rice tissues. The N-terminal amino acid sequence of the 33-kDa protein was determined and its coding region was identified on the RTBV genome. The identity of the coat protein gene was further confirmed by expressing a region of the genome in Escherichia coli, the products of which reacted with anti-RTBV antibody. The unusually long ORF 3 of RTBV is predicted to encode a polyprotein of 194.1 kDa that includes: the coat protein(s), viral proteinase, reverse transcriptase, and ribonuclease H. The sections of the polyprotein show varying degrees of similarity to the counterparts of Commelina yellow mottle virus (a member of the proposed badnavirus group) and caulimoviruses. The functions of the other three ORFs are unknown.

Amino Acid Sequence↗
PubMed1991

Rice tungro disease is caused by an RNA and a DNA virus.

We present evidence that rice tungro spherical virus (RTSV) has a genome of polyadenylated single-stranded RNA of about 10 kb whereas rice tungro bacilliform virus (RTBV) contains double-stranded circular DNA. RTBV DNA has been mapped and shown to have two discontinuities, one in each strand, at specific sites; it thus resembles that of the caulimoviruses. Gel electrophoresis of RTSV preparations revealed two protein bands (Mr 35K and 26K). RTBV yielded two major protein bands of 37K and 33K together with several minor species of higher and lower Mr which react with antiviral serum.

Capsid↗
PubMed1984

Tick-borne rickettsioses in Pune district, Maharashtra, India.

An extensive study on tick-borne rickettsioses in the Pune district of Maharashtra revealed that Indian tick typhus exists as a zoonosis, which only occasionally causes disease in man. By sero-conversion in guinea pigs, presumptive isolates of Rickettsia conori and Coxiella burnetii were recovered from 4 of the 11 species of ticks examined. Boophilus microplus and Rhipicephalus haemaphysalis were found to be harbouring R. conori whereas C. burnetii was isolated from Haemaphysalis intermedia and Hyalomma hussaini in addition to the above mentioned 2 tick species. Complement fixation tests carried out on sera from various species of rodents and gerbils revealed the presence of antibodies against the R. conori antigen in the sera of Rattus blanfordi, R.r. rufescens and Suncus murinus. In the case of large mammals, similar antibodies were detected in the sera from dog, cow, horse and sheep. C. burnetii infection was found to exist in both the sylvan and domestic cycle, as evidenced from the involvement of ticks, large and small mammals and man in its natural history.

Adolescent↗
PubMed1983

Zoonotic studies on influenza in pigs and birds, India, 1980-81.

Five hundred and twenty pig sera collected from Pune, Maharashtra State, India during 1980 were examined in Haemagglutination Inhibition (HI) tests to determine the antibody prevalence to nine human influenza virus strains covering the subtypes A(HON1), A(H1N1), A(H2N2), A(H3N2), type B and one swine influenza virus strain A(Hsw1N1). This study indicated considerable prevalence of antibodies to the four H3N2 strains isolated from 1973 onwards, particularly to the two recent H3N2 strains, limited prevalence of antibodies to H1N1 strain and absence of antibodies to the Hsw1N1 and HON1 influenza strains in the pig sera. Three hundred and eleven cloacal swab specimens collected from different species of domestic and wild birds from Kolar district, Karnataka State, India during 1980 and 1981 were investigated for influenza virus prevalence. No influenza virus was isolated from any of the specimen, but one strain of Newcastle disease virus was isolated from a chicken.

Animals↗
PubMed1982

Epidemiological, clinical, and virological features of influenza outbreaks in Pune, India, 1980.

During the course of continuous surveillance of influenza in 1980 in Pune, India, which has a tropical monsoon climate, three outbreaks of acute respiratory infection (ARI) were investigated in March (hot season), in July-September (rainy season), and in November (cold season); sporadic cases during the interepidemic months were also studied. The first outbreak was associated with influenza A virus (H3N2), the second with influenza A viruses (H3N2) and (H1N1) and influenza B virus, but fewer influenza viruses were isolated during the third outbreak. The illnesses affected all age groups including infants and adults over 60 years of age, although the paediatric age group was mainly affected. The ARI outbreaks associated with the hot and cold seasons commenced at about the time the weather changed whereas the mixed influenza A (H3N2) and A(H1N1) outbreaks occurred in the middle of the rainy season.

Adolescent↗