Coxsackie B virus infection and myopericarditis in Thailand, 1987-1989.

Serum specimens of 363 myopericarditis patients from the hospital all over the country were examined for coxsackie B virus antibody during 1987-1989 by means of microneutralization test in order to assess association between myopericarditis and coxsackie B virus infection. The data established that certain virus infection rates were 24.3%, 19.4% and 23.6% respectively, no differences in incidence were found between sex (p > 0.05) and the incidence rate between age groups below 15 years and 15 years and older was significantly different (p < 0.05). It was found that the epidemic happened throughout the year and the most common serotype in 1987 and 1989 was B4 whereas in 1988 it was B3.

The latency rate of human herpesvirus 6 (HHV6) in positive and negative human immunodeficiency virus (HIV) infection of intravenous drug users (IVDU).

The seropositive and latency rates of HHV6 among IVDU with positive and negative HIV and control group were demonstrated. By immunofluorescent antibody test, no differences in the seropositive rates were found among these three groups. All groups had seropositive rate at the average 89% and GMT antibody 1:26. This meant that most of them had previous infection with HHV6. In addition, HHV6-DNA was determined and classified into subgroups: HHV6A and HHV6B, by polymerase chain reaction. The prevalence of HHV6-DNA indicated HHV6 latency in vivo. High latency rate of HHV6 was found in all three groups (the average 54%). Moreover, HHV6B (49%) had a higher frequency than HHV6A (5%); HHV6a was found only in IVDU with or without HIV infection. The result suggested that the HHV6 latency in IVDU with positive HIV may possibly transactivate HIV. The pathogenesis of HHV6 in AIDS patients should be further investigated. However, this research finding is useful for treatment, health care, prevention and control of AIDS in case of dual infections and latency of herpesvirus infection in AIDS.

Treatment of herpes zoster with Clinacanthus nutans (bi phaya yaw) extract.

A randomized, placebo-controlled trial of the efficacy of topical formulation of Clinacanthus nutans (Bi Phaya Yaw) extract was carried out in 51 patients with varicella-zoster virus infection. The study medication was applied five times daily for 7-14 days until the lesions were healed. The number of patients with lesion crusting within 3 days and with lesion healing within 7 days and 10 days were significantly greater in the C. nutans extract-treated group than the placebo group (p < 0.01). Pain scores were reduced more rapidly in the C. nutans extract-treated group than in the placebo group. There were no side effects of the study medication.

Production of monoclonal antibody against hepatitis B surface antigen.

HBV infection is a major health problem in Southeast Asia. Thailand is considered to be an endemic area of HBV infection(18). Prevalence of HBsAg carriers is 5.2 per cent in children, 9 per cent in adults and 5.6 per cent in pregnant women(19,20). We believe that the monoclonal antibody described in the present report will be useful to develop HBsAg-KIT for national serologic screening assay, as considered in terms of sensitivity, specificity and cost effectiveness.

Serological and genetic characterization of bovine rotaviruses in Thailand by ELISA and RNA-RNA hybridization: detection of numerous non-serotype 6 strains.

A total of 62 fecal specimens positive for rotavirus were collected from diarrheic cows in Thailand in 1988 and 1989. The antigenic properties of rotaviruses in stool were examined by enzyme-liked immunosorbent assays using specific monoclonal antibodies directed at VP4, VP6 or VP7: all the bovine rotavirus strains were determined as subgroup I; none of the strains were reactive with serotype 6-specific monoclonal antibody; and different reactivities of the bovine strains with two anti-VP4 monoclonal antibodies were observed. Polyacrylamide gel electrophoresis of viral RNA exhibited three different RNA electropherotypes. In RNA-RNA hybridization experiments using cell culture-adapted three strains as well as a reference bovine strain (NCDV), RNA from the Thai bovine strains showed very low homology to that from NCDV; only three or four RNA segments were hybridized between the RNAs from Thai samples and NCDV. These results suggested that bovine rotaviruses isolated in Thailand are serologically and genetically distinct from a reference serotype 6 bovine strain, NCDV.

Detection of 27-32 nm virus-like particles in stools of non-A, non-B hepatitis patients in Thailand by immunoelectron microscopy.

A total of 142 sporadic cases of viral hepatitis in Thailand were tested for HAV and HBV infections. Thirty nine and 58 cases were serologically found to be associated with HAV and HBV infections, respectively. The remaining 45 cases were unrelated to infection by HAV or HBV. In nine of these cases, we detected 27-32 nm virus-like particles in stools by immunoelectron microscopy using a reference serum of enterically transmitted non-A, non-B hepatitis (Fausta 3/87). This finding implies that enterically transmitted non-A, non-B hepatitis is prevalent also in Thailand.

Immunofluorescence, enzyme-linked immunosorbent assay, particle agglutination and western blot for the detection of antibody to human immunodeficiency virus type 1.

Immunofluorescence assay (IFA) has been applied for detection of antibody to human immunodeficiency virus type 1 (HIV-1). To compare the IFA with an enzyme-linked immunosorbent assay (ELISA) and particle agglutination (PA), we examined the antibody response to HIV-1 in 475 sera from AIDS, PGL and ARC patients as well as several risk groups and healthy persons by three methods. The positive results by any methods were confirmed by western blot (WB). The results by all methods were well correlated on the sera from 45 asymptomatic male homosexuals and 70 female prostitutes. There were some false positive results by ELISA in the sera from prisoners and healthy persons. Four sera from drug abusers were positive only by PA and IFA and were negative by ELISA. All were WB-inconclusive. Particle agglutination and IFA results were compared with western blot analysis on 208 ELISA-positive sera. All IFA-strongly positive sera (84%) were positive by western blot. The sera with weakly positive, negative and inconclusive results by IFA (16%) were possibly any of positive, inconclusive or negative by western blot. By PA, 200 of 208 (97%) sera were PA-positive and 1% of these sera were WB-inconclusive while the PA-negative sera were either negative or inconclusive by western blot. These results suggested that PA is a simple and sensitive method for screening of HIV-1 antibody while IFA could be a primary confirmatory test and western blot would then be used for confirming any IFA-negative or inconclusive results.

A long term study of rotavirus infection in Thai infants and children with diarrhoea.

During 1977-1980, human rotavirus was detected by electron microscopic technique in the stool of 55 (30.7%) of 179 patients, hospitalized in Bangkok Metropolis. Characteristic particles 65-70 nm in diameter, round shape, resembling a little wheel with radius capsomeres from the dense core. Other some adenovirus and small virus particles were seen, 2.8% and 2.2% respectively. Seasonal distribution among Thai patients with rotavirus infection mostly occurred in January (58.8%). The youngest patient in this study was 30 days old, and the frequency of human rotavirus infection was highest at age six to eleven months.