Cross-challenge studies in rhesus monkeys employing different Indian isolates of hepatitis E virus

The aim of this study was to determine if rhesus monkeys infected with one isolate of hepatitis E virus (HEV) were immune to subsequent challenge with other isolates of the virus. Three epidemic and one sporadic Indian HEV isolates were employed in the study. The interval between primary inoculation and challenge varied from 1 year and 6 months to 2 years and 9 months. Evidence of HEV infection was ascertained by rise in serum alanine transaminase (ALT) levels and/or seroconversion to antibodies to HEV (anti-HEV), and the presence of HEV-RNA in the bile or faeces of the infected monkeys. No evidence for multiplication of virus in monkeys challenged with different HEV isolates was obtained. These results show that immunity generated by one isolate of HEV protects against different isolates of hepatitis E virus.

Epitope mapping of dengue 1 virus E glycoprotein using monoclonal antibodies

Ten monoclonal antibodies (MAbs) were raised against dengue 1 (DEN 1, Hawaii) virus E glycoprotein. Specificity of the MAbs was tested by ELISA and immunofluorescence. Eight were DEN 1 type-specific, one was DEN group-reactive (DGR) and one was flavivirus cross-reactive (FCR). Two of these type specific MAbs exhibited haemagglutination-inhibition (HI) and neutralized (N) DEN 1 virus in vivo (HS). These two MAbs showed 100% protection against a challenge of 100 LD50 of DEN 1 virus in adult Swiss albino mice. The remaining six MAbs were HI negative, N negative and non-protective against challenge (NHS). Of these only three were reactive in the CF test. The DGR, FCR and one of the NHS MAbs (NHS-3) did not react with DEN 1 virus grown in Vero cells, whereas they reacted with DEN 1 virus grown in LLC-MK2 and C6/36 cells in immunofluorescence, probably indicating a difference in the synthesis/processing of viral proteins in these different cell lines. An epitope map of the E gp was drawn using a computer programme based on the additivity index values. The epitope map delineated five domains, a) S-I representing type-specific, HI positive, N positive and protecting MAbs. b) S-II representing type-specific, HI negative, N negative MAbs. c) S-III representing type-specific HI/N negative MAb, but distinct from S-II. d) DGR representing HI/N negative DEN group reactive MAb. e) FCR representing HI/N negative flavivirus cross-reactive MAb. Epitope analysis of a number of different DEN 1 strains isolated in India over a period of 30 years showed that the domains S-II and S-III which react with HI negative, DEN-1 specific MAbs were variable. The DGR domain and the S-I domains were conserved.

Contribution of HEV and HCV in causing fulminant non-A, non-B hepatitis in western India

During 1990, 38 patients with fulminant non-A, non-B hepatitis (NANB) died in Government Medical College Hospital, Aurangabad. Serum samples from these patients were tested for antibodies to hepatitis C virus (anti-HCV) and IgM antibodies to hepatitis E virus (IgM-anti-HEV). All samples were also subjected to polymerase chain reaction (PCR) for the detection of HBV DNA, HCV RNA and HEV RNA. None of the patients had circulating anti-HCV antibodies; three had HCV RNA. Based on anti-HEV-IgM positivity 14 patients (37%) could be diagnosed as suffering from hepatitis E. None was positive for HEV RNA. In the absence of serological markers, HBV DNA was present in three cases. None of the HBV DNA positive patients had anti-delta antibodies. Dual infections (HBV with HEV, and HBV with HCV) were seen in two cases. The aetiology of half of the NANB cases could not be assigned to the known hepatitis viruses using current techniques.

Cervical spine in psoriasis

X-rays of the cervical spines from patients with psoriasis and psoriatic arthritis were compared with similar films from a control population. Apophyseal narrowing, sclerosis, and calcification of anterior ligamants were found more commonly in patients than in controls.

Counselling in HIV/AIDS--an Indian perspective

AN overview of the general principles of counselling for HIV/AIDS are overviewed. Relevance of 'shared confidentiality' in Indian context is recommended.

Growth and cytopathic effect of Japanese encephalitis virus in astrocyte-enriched cell cultures from neonatal mouse brains

Neuron-free, astrocyte-enriched brain cell cultures from newborn mice could be infected with Japanese encephalitis virus (JEV) as evidenced by immunofluorescence (IF), viral replication and cytopathic effect (CPE). Virus-specific cytoplasmic fluorescence was detectable in astrocytes first after 18 hrs, released infectious progeny virus in the culture fluid after 24 hrs, and CPE after 11 days post infection (p.i.).

Prevalence of anti-HCV antibodies in western India

Nearly 2000 serum samples collected from different risk groups from Pune and Bombay metropolitan areas were tested for antibodies to hepatitis C virus (anti-HCV) by Recombinant Immunoblot Assay-3 (RIBA-3). Patients undergoing haemodialysis showed 24.5 per cent seropositivity whereas 5.7 and 5.3 per cent of multiply transfused patients (>2 units) and chronic liver disease patients respectively were anti-HCV positive. Leprosy patients had almost 0.7 per cent seropositivity. In other risk groups the positivity rate was nil. In normal population only one out of 830 persons had anti-HCV antibodies. It is therefore apparent that the prevalence of hepatitis C virus (HCV) in western India is not high. However, special care needs to be taken for dialysis patients. As none of the 430 pregnant women and 86 children below the age of 5 yr were anti-HCV positive, vertical mode of HCV transmission seems to be negligible.

Age-specific prevalence of antibodies to hepatitis A and E viruses in Pune, India, 1982 and 1992

The age-specific seroprevalence of antibody to hepatitis A virus (HAV) and antibody to hepatitis E virus (HEV) were studied in persons in Pune, India, where both viruses are endemic. The data showed that HAV infected the majority of persons by age 3 years and virtually 100% by late childhood. In contrast, infection with HEV was rare in children and did not reach peak prevalence (33%-40%) until early adulthood. The reason for the differences in infection rates between HAV and HEV is not known. Age-specific antibody patterns in serum samples obtained 10 years apart show that neither HAV nor HEV has diminished in medical importance in this Indian community.

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.

Nucleotide sequence of cDNA encoding bonnet monkey (Macaca radiata) zona pellucida glycoprotein-ZP3

The cDNA encoding bonnet monkey zona pellucida ZP3 from bonnet ovary has been amplified by polymerase chain reaction. The ZP3 gene has an open reading frame of 1272 nucleotides encoding a polypeptide of 424 amino acid residues which shares 93.9% overall identity with human ZP3. Bonnet ZP3 has four potential attachment sites for N-linked sugar chains which are also conserved in human ZP3. Bonnet ZP3 has 14 cysteine residues compared with 15 in human ZP3. The highest disparity between these molecules was restricted to a domain represented by amino acid residues 370-398. These results have important implications for the use of bonnet monkey as an animal model for evaluation and development of contraceptive vaccine based on ZP3 for human use.

Antibodies against hepatitis E virus in Old World monkeys

To examine whether Indian monkeys are infected with hepatitis E virus (HEV) in nature, serum samples from wild rhesus (Macaca mullata), bonnet (M. radiata) and langur (Presbytes entellus) monkeys were screened for anti-HEV IgG antibodies in recombinant antigen-based ELISA assays. The positivity rates were 36.7%, 19.1% and 2% respectively. The protection of such antibodies against human HEV was studied in four rhesus monkeys. Of the two rhesus monkeys with anti-HEV titres of 100 and 1000 respectively which were inoculated with the KOL-91 strain of HEV, the former demonstrated a 10-fold rise in anti-HEV titres. Anti-HEV titre in the second rhesus monkey remained unchanged. Neither of the monkeys showed any rise in serum alanine transaminase (ALT) or presence of virus in the faeces, as tested by polymerase chain reaction (PCR). Two other rhesus monkeys with anti-HEV titres of 10,000 and 100 respectively were inoculated with the AKL-90 strain of HEV. Serum ALT levels and anti-HEV titres remained unchanged in the first monkey. Excretion of virus in faeces was not noted (PCR). The second monkey developed a typical HEV infection. HEV infection could be produced in anti-HEV negative control monkeys inoculated with both strains of HEV. These results show that either human or simian HEV, or a closely related agent, is circulating among Indian macaques. Titre-dependent protection of naturally occurring anti-HEV antibodies supports this view.

Inheritance of oral susceptibility of Aedes aegypti to Chikungunya virus

A colony of rosy eye mutants of Aedes aegypti was established. This strain was refractory to Chikungunya virus by oral route of infection when compared with the wild-type parent strain. The refractoriness of this strain seems to be due to a mesentronal barrier, since both the mosquito strains supported the multiplication of virus after intrathoracic inoculation. The rosy eye strain was also found to be refractory to Sagiyama virus (Alphaviridae: Getah virus subtype) when compared with wild-type parent strain, but no such difference in the oral susceptibility was found with dengue-2 (Flaviviridae) virus. The rosy eye mutant appears to be closely linked to the gene(s) for refractoriness to alpha viruses and may be useful in future studies in understanding the genetic basis of vector competence of Ae. aegypti to arboviruses.

Effect of sublethal dosages of insecticides on chikungunya virus susceptible and refractory strains of Aedes aegypti

Three strains of Aedes aegypti mosquitos viz (i) CRS, refractory to Chikungunya (CHIK) virus by oral route of infection but susceptible to DDT (2) CSS, susceptible to CHIK virus and also susceptible to DDT (3) CSS-DDTR, susceptible to CHIK virus but resistant to DDT, were examined for the effect of sublethal dosages of DDT and deltamethrin on their fecundity. Biochemical analysis showed that there was an increase in glutathione s-transferase activity in the CSS-DDTR strain which was associated with DDT resistance. There was an increase in acetylcholinesterase activity in the CRS strain, however it was not associated with resistance to all the three insecticides tested. No significant differences in the fecundity of these three strains were observed, though there was some increase in the number of non layers in CSS-DDTR strain after the treatment of DDT and mean number of eggs laid by CSS and CRS strains was slightly reduced (0.5 > p < 0.1) after the treatment with deltamethrin.

Detection of human immunodeficiency virus antibody among homosexual men from Bombay

BACKGROUND AND OBJECTIVES

In India, heterosexual transmission of HIV-infection is considered to be the major mode of transmission. However, no report is available on transmission of HIV-infection among homosexually active men. The prevalence of human immunodeficiency virus-1 (HIV-1) and human immunodeficiency virus-2 (HIV-2) infections among homosexual men from Bombay is discussed.

GOAL OF THE STUDY

To determine the extent of presence of anti-HIV-1, anti-HIV-2 antibodies, or both anti-HIV-1 and anti-HIV-2 antibodies among homosexual men in India.

STUDY DESIGN

Sixty-three blood samples were collected from two STD clinics of Bombay over a 6-month period from men with a history of homosexual behavior who were asymptomatic for HIV-infection. The mean age of the subjects was 31.6 years. For serological detection anti-HIV-1 antibody ELISA was used as the primary screening test followed by Western blot to confirm the results. For distinction between anti-HIV-1 and anti-HIV-2 antibody, line immunoassay was used. The sexually transmitted diseases (STDs) were diagnosed clinically, although Venereal Disease Research Laboratory (VDRL) tests were carried out as a routine test for screening STDs. For detection of gonorrhea, Gram stains of urethral smear were done routinely.

RESULTS

From the 63 blood samples tested, 10 samples were reactive by ELISA for HIV-1 infection, and three samples were borderline reactive. These three samples were found to be reactive for anti-HIV-2 by the line immunoassay. The above 10 samples were also positive by Western blot for anti-HIV-1 antibody. Two blood samples were positive for both anti-HIV-1 and anti-HIV-2 antibodies. Using clinical diagnosis as the criteria, the different types of STD among the 63 subjects were as follows: condylomata (22), herpes (20), gonorrhea (15), candidiasis (3), and syphilis (3). However with VDRL, seven subjects were found to be reactive. Gram stains indicated gonorrhea in all the 15 subjects.

CONCLUSIONS

This study reports for the first time the homosexual transmission of both HIV-1 and HIV-2 infections in India, although heterosexual transmission still is the major mode of transmission of the infection. The associated incidence of STDs among these men and that a few of these subjects were bisexual make them at high risk for transmission of HIV infection.

Detection and cloning of potent transforming gene(s) from chewing tobacco-related human oral carcinomas

High molecular weight DNA isolated from 14 primary tumour tissues of human oral carcinoma patients was analysed for transforming activity by NIH3T3 co-transfection assay using pSV2neo gene as a selectable marker, followed by nude mouse tumorigenicity assay. Ten of the patient tumour tissues demonstrated molecular lesions in myc, ras or/and EGF-R genes, whereas 4 patients did not show tumour associated aberrations in these oncogenes. The G418-resistant transfected cells from 12 of 14 individual patients demonstrated transforming potential by colony formation in soft agar and tumour induction in nude mice within 25-80 days. DNAs from the transfected cells, consequent nude mice tumours and corresponding cell lines, contained human Alu sequences. Southern blot hybridisation with ras, myc, EGF-R oncogenes demonstrated the presence of human H-ras oncogene in one of the 12 sets of nude mice tumours. In contrast, DNA from the other 11 sets of nude mice tumours indicated absence of c-myc, N-myc, L-myc, H-ras, K-ras, N-ras and EGF-R genes on Southern analysis. Further, DNAs from five first cycle tumorigenic transformants were subjected to a second cycle of transfection, and induced tumours in nude mice with a shorter latency period of 21-50 days. The secondary transformants contained discrete human Alu sequences; however, the DNA did not hybridise with myc/ras/EGF-R probes. A genomic library was constructed from a second cycle nude mice tumour, using EMBL-3 as the vector. Four human Alu sequence positive clones were isolated on screening 2 x 10(5) plaques, and one of the recombinant clones subjected to fine restriction mapping using 16 restriction enzymes. The lack of association of the nude mice tumour DNA with myc/ras/EGF-R showing aberrations in the primary human tumour, implies activation of an alternative potent transforming gene(s) in the chewing tobacco-related oral carcinomas in India.

Experimental studies on the susceptibility of domestic pigs to West Nile virus followed by Japanese encephalitis virus infection and vice versa

A study on the susceptibility of domestic pigs to West Nile virus (WNV) and Japanese encephalitis virus (JEV) infection was carried out. One batch of pigs was inoculated with WNV followed by JEV and another batch was inoculated vice versa. The first batch developed low level of viraemia and haemagglutination-inhibition (HI) antibodies to both viruses. There was a booster effect on the already existing WNV antibodies after challenging with JEV. In the second batch the animals developed high level of JE viraemia but did not develop WN viraemia. They developed HI antibodies to both JEV and WNV with low booster effect of WNV infection on JEV antibodies. Fresh batches of pigs were infected through bite of WNV- and JEV-infected Culex vishnui mosquitoes. WNV-infected pigs did not show viraemia, whereas JEV-infected ones developed JE viraemia. The study indicated that pigs were poor hosts for WNV but good ones for JEV. However, WNV antibodies reduced the level of JE viraemia and JEV infection boosted the already existing WNV antibodies.

Indigenous anti-hepatitis A virus IgM capture ELISA for the diagnosis of hepatitis A

Anti-hepatitis A virus IgM capture ELISA was developed by using the reagents produced in the NIV laboratory. The major reagents of the assay were anti-human IgM antibody, hepatitis A virus (HAV) and anti-HAV IgG-horse radish peroxidase (HRP) conjugate. Of these, anti-human IgM antibodies were generated in rabbit against IgM secreted by human hybridoma clone(G3). HAV was derived from buffalo green money kidney cell line infected with HM-175 strain. Virus purified from the cell lysates was used for immunization of rabbits and guinea-pigs. There was very low anti-HAV response. A seropositive rhesus monkey was inoculated with monkey adapted strain of HAV to boost the anti-HAV antibody titre. Anti-HAV IgGs derived from hyperimmune sera of monkey and hepatitis A patient were conjugated with HRP. The preparations of conjugate--particularly human antibody--HRP conjugate yielded highly satisfactory results in anti-HAV capture ELISA. The assay appears to be specific, sensitive and quick and is useful in differentiating acute HAV infection from other acute infections caused by B, E and non-A non-B hepatitis viruses.

Measles outbreak in a tribal population of Thane district, Maharashtra

In March 1992, an outbreak of measles, in the tribal population of Vavar village, Mokhada Taluk, Thane district, Maharashtra, was investigated. Two hamlets of Vavar village namely Sagpanipada (epidemic in October, November 1991) and Behedpada (epidemic in January, February 1992) were affected. In both hamlets, measles cases were confined to children below 10 yrs and 96% of the cases occurred in children below 6 yrs. Attack rates were 52.7% and 51.4% and case fatality rates were 31.2% and 15.6% at Sagpanipada and Behedpada, respectively. All the convalescent patients' sera possessed IgM antibodies against measles. A clear drop in IgM and a rise in IgG antibodies against measles was observed in 35 paired samples from convalescent patients. Fifty four per cent of sera from controls, possessed IgM antibodies. Migrating population appeared to have imported measles which flared up in an epidemic among the susceptibles. Priority immunization of the children of remote isolated populations may prevent such epidemics.

Seroepidemiology of water-borne hepatitis in India and evidence for a third enterically-transmitted hepatitis agent

Many epidemics of water-borne hepatitis have occurred throughout India. These were thought to be epidemics of hepatitis A until 1980, when evidence for an enterically transmitted non-A, non-B hepatitis was first reported. Subsequently, hepatitis E virus was discovered and most recent epidemics of enterically transmitted non-A, non-B hepatitis have been attributed to hepatitis E virus infection. However, only a limited number of cases have been confirmed by immuno electron microscopy, polymerase chain reaction, or seroconversion. In the present study we have performed a retrospective seroepidemiologic study of 17 epidemics of water-borne hepatitis in India. We have confirmed that 16 of the 17 epidemics were caused at least in part by serologically closely related hepatitis E viruses. However, one epidemic, in the Andaman Islands, and possibly a significant minority of cases in other epidemics, appears to have been caused by a previously unrecognized hepatitis agent.