The emergence of YMDD mutants precedes biochemical flare by 19 weeks in lamivudine-treated chronic hepatitis B patients: an opportunity for therapy reevaluation

Given the loss of therapeutic efficacy associated with the development of resistance to lamivudine (LMV) and the availability of new alternative treatments for chronic hepatitis B patients, early detection of viral genotypic resistance could allow the clinician to consider therapy modification before viral breakthrough and biochemical relapse occur. To this end, 28 LMV-treated patients (44 +/- 12 years; 24 men), on their first therapy schedule, were monitored monthly at four Brazilian centers for the emergence of drug resistance using the reverse hybridization-based INNO-LiPA HBV DR assay and occasionally sequencing (two cases). Positive viral responses (HBV DNA clearance) after 6, 12, and 18 months of therapy were achieved by 57, 68, and 53% of patients, while biochemical responses (serum alanine aminotransferase normalization) were observed in 82, 82, and 53% of cases. All viral breakthrough cases (N = 8) were related to the emergence of YMDD variants observed in 7, 21, and 35% of patients at 6, 12, and 18 months, respectively. The emergence of these variants was not associated with viral genotype, HBeAg expression status, or pretreatment serum alanine aminotransferase levels. The detection of resistance-associated mutations was observed before the corresponding biochemical flare (41 +/- 14 and 60 +/- 15 weeks) in the same individuals. Then, if highly sensitive LMV drug resistance testing is carried out at frequent and regular intervals, the relatively long period (19 +/- 2 weeks) between the emergence of viral resistance and the onset of biochemical relapse can provide clinicians with ample time to re-evaluate drug therapy.

A cluster of acute hepatitis E infection in United Nations Bangladeshi peacekeepers in Haiti

In the fall of 1995, within a month of deployment to Haiti for peacekeeping duty, four Bangladeshi soldiers developed acute icteric hepatitis in rapid succession. Hepatitis E virus (HEV) was found to be the etiology by demonstrating HEV genomic sequences in serum samples by the polymerase chain reaction (PCR) and serologically by the detection of elevated IgM titers to HEV. No case had serologic evidence of acute hepatitis A or C infection. The soldiers had probably acquired their infection while living in a cantonment area outside Dhaka, Bangladesh for one month prior to deployment. Cloning and sequencing of amplified PCR products demonstrated a single strain suggestive of a common source of infection. Furthermore, high genomic identity with Asian strains of HEV and dissimilarity with the Mexican strain was demonstrated, verifying that the strain had indeed been imported. Human waste management from the Bangladesh camp in Haiti was strictly controlled and no secondary cases were observed. A convenience sample of 105 (12%) soldiers from the Bangladesh battalion (850 men) revealed anicteric or asymptomatic HEV infection in seven (7%) of 105. This report contains the first demonstration of acute hepatitis E in natives of Bangladesh and demonstrates the power of the PCR in the rapid diagnosis and epidemiologic analysis of HEV infection. More importantly, this cluster demonstrates the importation of an important infectious disease by multinational peacekeepers to a potentially susceptible host country.

Serological evidence of rotavirus infection in a guinea pig colony

Antibodies reacting with simian rotavirus SA11 were detected by enzyme immunoassay (EIA) and Western blot assay (WBA) in sera from guinea pigs bred for experimental use at the Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. The proportion of antibody-positive animals and the antibody titres rose sharply in 1985, were maintained at a high levels in 1986 and declined in 1987. There were no obvious signs of disease coinciding with serological evidence of infection. Results of WBA suggest that the virus involved belongs to subgroup 1 of group A rotaviruses.

A combined dot nitrocellulose-enzyme immunoassay for rotavirus and adenovirus

A combined enzyme immunoassay using nitrocellulose membrane as solid support is described for the detection of rotavirus and adenovirus in faeces from children with gastroenteritis. Its sensitivity and specificity are comparable to those of a previously described assay performed on plastic microplates (Pereira et al. (1985) J. Virol. Methods 10, 21-28). The introduction of nitrocellulose membrane as support for the immune reactions greatly simplifies the multiple washing steps and precludes the need for disposable plastic plates.

A comparison of simian rotavirus SA11 preparations maintained in different laboratories

Preparations of simian rotavirus SA11 maintained in different laboratories were compared with each other by polyacrylamide gel electrophoresis of genomic RNA. Differences in the migration of genome segments 4, 5 and 7 allowed the classification of eight virus preparations into four electrophoretic types.

Diarrhoea in mice infected with a human rotavirus

Oral inoculation of newborn mice with the MET strain of human rotavirus produced transient diarrhoeal disease. Light and scanning electron microscopy showed typical rotavirus-induced morphological lesions in the villous epithelium of the small intestine consisting of extensive cytoplasmic vacuolation, villous necrosis and atrophy. Virus recovered from intestinal suspensions of infected mice showed the typical electrophoretic profile of the genome of the inoculated strain. Rotavirus antibody appeared in infected mice 10 to 20 days after inoculation but not in controls or nursing dams. The availability of a small animal model for experimental infection with human rotaviruses should prove useful for virulence and protection studies.

Polymorphism of the migration of double-stranded RNA genome segments of avian reoviruses

A number of field isolates of avian reovirus were characterized by analysis of the migration pattern of their genomic double-stranded RNA (dsRNA) segments upon polyacrylamide gel electrophoresis. Comparison of the various isolates has demonstrated (i) no relationship between serotype and migration of any individual dsRNA segment, (ii) marked polymorphism of migration patterns of all dsRNA segments among isolates of the same serotype as well as among different serotypes, (iii) no correlation between genotype and disease state, (iv) less marked variability in migration pattern from isolates within a restricted geographic locale compared to isolates from distant locales, (v) the presence of a single genotype in local outbreaks of disease, and (vi) the relative invariant migration of several dsRNA segments among the avian reoviruses, one of which (S1) may serve to distinguish the avian from the mammalian reoviruses.

Polymorphism of the genomic RNAs among the avian reoviruses

The genome of avian reoviruses is comprised of 10 segments of double-stranded (ds)RNA. Analysis by polyacrylamide gel electrophoresis of the genomic RNA from a small number of avian reoviruses has demonstrated a significant polymorphism in the migration pattern of the dsRNA segments among different isolates. Comparison of these patterns with that of the mammalian reovirus of serotype 1 has permitted calculation of the molecular weights of the avian dsRNA species.