Epidemiological study of enteric coronavirus excretion by an enzyme-linked immunosorbent assay.

The enzyme-linked immunosorbent assay with a blocking test was used to determine the prevalence of enteric coronavirus excretion among the population of Bangkok and Khon Kaen province. The results indicated that coronaviruses were present in fecal samples from both children and adults with or without diarrhea. It is interesting that the viruses were more frequently observed in the apparently healthy individuals in Bangkok than in the patients with diarrhea whereas the excretion rates were approximately alike in both groups in Khon Kaen province. Among children aged less than 5 years (with or without diarrhea) the viruses were more frequently observed in stools from young children (1-5 years old) than from the newborn (less than 1-year-old) particularly those living in the Bang Khen slum area and in the rural Khon Kaen community. The rate of coronavirus excretion did not increase with age and some apparently healthy individuals continued to excrete the viruses for several months. The results also suggested that chronic parasitic infection associated with low socioeconomic status might influence the excretion of enteric coronaviruses in the feces.

Immunodiagnosis of snake venom poisoning.

Uncertainty as to the species diagnosis remains a serious problem in the management of snake venom poisoning. This is particularly so in areas inhabited by numerous species, the venoms of which elicit similar pharmacological effects and clinical symptoms and against which para-specific cross-neutralizing antivenom is not available. Attempts have been made to eliminate some of this ambiguity through the development of various immunodiagnostic tests. Tests based on ELISA are sensitive, specific and even quantitative and adaptable to field application. In the development of diagnostic tests for use in developing countries, however, practical consideration must be given to speed, cost, simplicity in terms of equipment and expertise, and stability to the climate and storage conditions. This may dictate further modification or selection of more suitable alternative methodologies. Furthermore, the test may have to allow more flexibility in accommodating local species distributions and to address probable complications of heterophile antibodies in test samples from rural people.

T-cell subpopulations in tuberculosis and the effects of rifampicin.

T-cell subpopulations were evaluated by several recent methods in 38 tuberculosis patients (24 active and 10 quiescent cases of pulmonary tuberculosis; two of miliary and two of active extra-pulmonary tuberculosis) before and during rifampicin (RMP) treatment. There was a significant reduction in the total number of T cells (E-RFC and OKT3+ cells) and of helper T cells (OKT4+) coinciding with an increase in the number of suppressor T cells when the 38 tuberculosis patients were compared with 21 healthy control subjects. When the changes of T-cell subpopulations in groups of subjects and patients with different clinical forms of the disease were analysed, these changes could be clearly shown with both sets of assays (receptor assays and monoclonal antibody assays) among those with the active pulmonary form of tuberculosis while similar changes could be demonstrated only by one or the other assay among those with the other forms of the disease. The effects of one month of RMP treatment on these parameters were much more obvious among the clinically active patients than the quiescent patients, i.e. a recovery of total T cells from a low pre-treatment to a near normal level accompanied by a significant reduction in the number of suppressor cells (OKT8+). In fact, among quiescent patients the number of suppressor cells (as TG) appeared to rise further with RMP treatment.