Key words : HIV infection, HCV infection, patients attending STD clinics.

                    A cross-sectional study of 400 patients attending sexually transmitted disease (STD) clinics at The Venereal Diseases and AIDS Centers, Regional 2, Thailand, was conducted from January to December 1996 in order to investigate the antibody prevalence to human immunodeficiency virus (HIV) and hepatitis C virus (HCV) and to describe some epidemiological characteristics among HIV and HCV co-infected individuals. The studied patients were interviewed and their blood specimens were collected for determining anti-HIV and anti-HCV antibodies. The results revealed that the prevalence of anti-HIV among studied patients was 25%, while 7.5% were positive for anti-HCV. The positivity of both antibodies present in the same individuals was 3.3% (13/400 cases). The highest prevalences of anti-HIV, anti-HCV and both antibodies were found in studied patients aged 20 years or less. Patients with primary education, or lower, had relatively higher prevalence of anti-HIV and/or anti-HCV than those with higher level education. A relatively higher prevalence was found among commercial sex workers and labourers. Among 13 HIV and HCV co-infected individuals, there were four cases who had histories of sexual contact without condom use, but no history of parenteral contact. The rest (9/13) had histories of both parenteral contact and sexual contact without condom use.

(Asia Pac J Public Health 2000;12(1):41-45)

  POLIO SEROSURVEILLANCE ON CHILDREN UNDER 5 YEAR IN TWO
  CONGESTED COMMU-NITIES OF BANGKOK (NO. 540)

Key words: Poliovirus, neutralizing antibody, immunization, cogested community.

                    Thailand implementation of polio eradication is now in the final stages, focusing on mopping-up immunization in high-risk area where the virus is suspected to be still circulating. Other criteria include overcrowding, dynamic population, poor sanitation and low immunization coverage. The aim of this study is to detect neutralizing antibody against 3 types of Polioviruses among children under 5 years in two congested communities; Rim Tang Rot Fai and Klong Lampak communities, Dusit District, Bangkok. The study included 158 children living in the two communities during August 1996. History of taking polio immunization and finger prick blood of the children were collected for neutralizing antibody detection by standard WHO microneutralization procedure. Polio vaccine coverage was 77.2%, incomplete immunization 17.7%, uncertain history 3.2%, and no immunization 1.9%. Among those with complete immunization, 9% had no protective immunity against Poliovirus iype 3 (titer ~ 1:8). Furthermore 11.4% of the study population had no protective immunity against one or more types of Polioviruses. Geometric mean titers of all types of polioviruses were significantly higher than other groups (p<0.05). GM titers of Poliovirus type 3 were the lowest. This study showed that the children in the congested area with high rate of migration and poor health infrastructure such as these 2 communities had a risk of polio infection up to 11.4%. The approaches toward polio eradication for these high-risk areas should include mass immunization, providing safe drinking water and health education including disease prevention and personal hygiene.

(Journal of Public Health, January-April 2000, Vol. 30 No. 1)

  COMPARATIVE EVALUATION OF THE THREE AMPLICON DETECTION
  METHODS FOR DETECTION OF IS6110-PCR PRODUCTS FROM
  MYCOBACTERIUM TUBERCULOSIS (NO. 541)

                    IS6110-PCR based method with a new designed primer pair that amplifies a 377-bp target located at the end region of the insertion sequence IS6110 was used for the direct detection of Mycobacterium tuberculosis in sputum samples. The PCR products were examined by the three detection methods; agarose gel electrophoresis in the presence of ethidium bromide and by hybridization in a Southern blot, and dot blot format to a fluorescein-labeled internal oligonucleotide probe with detection by chemiluminescence. The detection limit of the PCR assay for M. tuberculosis DNA was 1 pg by gel electrophoresis and 10 fg by Southern blot or dot blot hybridization. To evaluate the clinical applicability of the PCR assay by various amplicon detection methods, the results were compared with direct acid-fast microscopy, and culture, and the culture method was used as the “gold standard.” A total of 328 sputum samples, which included 134 culture-positive specimens and 194 culture-negative specimens, were examined. Compared with culture, PCR showed overall sensitivity, specificity, positive predictive value, negative predictive value, and efficiency of 88.1, 100, 100, 92.4, and 95.1 percent, respectively for agarose gel electrophoresis; and 96.3, 99.5, 99.2, 97.5, and 98.2 percent, respectively, for Southern hybridization, and 96.3, 85.1, 81.6, 97.1, and 89.6 percent, respectively, for dot blot hybridization. The results clearly showed that PCR by Southern hybridization gave the highest accuracy; its efficacy of detection M. tuberculosis in smear-positive sputum specimens was 100 percent, and in smear-negative sputum specimens was 97.5 percent, with only 0.5 percent false-positive result. However, this method gave 3.7 percent false-negative results from samples of negative smear. The high degrees of sensitivity and specificity of the IS6110-PCR based method with this primer pair and amplicon detection by Southern hybridization suggest that it should be very useful in clinical laboratories for rapid detection of M. tuberculosis in sputum samples.

(J Infect Dis Antimicrob Agents 2000 (1); 17 : 13-22.)

  RAPID DETECTION OF POLIOVIRUSES IN ENVIRONMENTAL WATER
  SAMPLES BY ONE-STEP DUPLEX RT-PCR (NO. 542)

Unchalee Tansuphasiri¹, Kanda Vathanophas¹, Anong Pariyanonda¹, Leera Kittigul¹, Fuangfa Utrarachkij¹, Pornphan Diraphat¹, Kanokrat Siripanichgon¹, Supornvit Punchitton¹, Kitja Chitpirom¹ and Nattasai Cheaochantanakij¹