ชื่อรางวัลที่ได้รับ รางวัลชนะเลิศในการนำเสนอโปสเตอร์จากการประชุมแพทย์ทหารภาคพื้นเอเซียแปซิฟิค
ครั้งที่ 22 ( Asia-Pacific Military Medicine conference XXII ) ในวันที่ 31 เม.ย. – 4 พ.ค. 55
ชื่อโครงการวิจัย Dot- ELISA Rapid Test Using Recombinant 56-kDa Protein Antigens for
Serodiagnosis of Scrub Typhus
Serodiagnosis of Scrub Typhus
หัวหน้าโครงการ พ.ท. วุฒิกรณ์ รอดความทุกข์
ปีที่ได้รับรางวัล 2555
Dot- ELISA Rapid Test Using Recombinant 56-kDa Protein Antigens for Serodiagnosis off Scrub Typhus
Wuttikon Rodkvamtook1, 2, Zhiwen Zhang3, Erin Huber3, Chien-Chung Chao4, John Grieco3, Dharadhida Bodhidatta1, Suparat Kanjanavanit5, Narongrid Sirisopana1 and Wei-Mei Ching4
1Armed Forces Research Institute of Medical Science, Royal Thai Army,
2Department of Microbiology, Phramongkutklao College of Medicine, Bangkok, Thailand.
3Preventive Medicine & Biometrics Department, Uniformed Services University of the Health Sciences (USUHS), Bethesda, Maryland, USA.
4Naval Medical Research Center (NMRC), Silver Spring, Maryland, USA.
5Nakhornping Hospital, Chiang Mai, Thailand.
Abstract
The first case of scrub typhus in Thailand was reported in 1952. Since then, scrub typhus has been recognized as one of the important tropical diseases affecting the military in Thailand. This is especially true for military personnel who are on duty along the borders. Scrub typhus is an important febrile disease of humans caused by the bacterium Orientia (formerly Rickettsia) tsutsugamushi. O. tsutsugamushi is a gram negative, intracellular, rod-shaped (coccobacillus) bacterium. It is transmitted to humans by the chigger bite. Scrub typhus can be diagnosed by clinical and laboratory techniques. Clinical diagnosis is often made by non-specific clinical symptoms and patient exposure history. The indirect immunofluorescent assay (IFA) has been the gold standard for laboratory diagnosis. However, it a requires fluorescent microscope, experienced technical staff, and growing Orientia in large quantities in a BSL-3 facility. A cheap, rapid, easy to use, sensitive and specific assay is needed particularly in endemic rural area such as Thailand. We have developed a rapid dot- enzyme linked immunosorbent assay (dot-ELISA) using the combination of recombinant 56-kDa protein antigens which exhibited broad reactivity with serum antibodies against the four most prevalent strains (Karp, Gilliam, Kato and TA763). The assay is rapid (30 min), can be done at room temperature, and the result can be read using the naked eye. No instrument is required except a simple shaker for washing the membrane. Sera of 142 pediatric patients from Nakhornping Hospital Chiang Mai Thailand, suspected of scrub typhus were tested using this dot-ELISA. 73 patients (51%) were found to be positive. The sensitivity and specificity of dot-ELISA using recombinant 56-kDa protein antigen were compared with the IFA test using the cutoff titer of IgM/IgG greater than 1:400/1:400.The dot-ELISA had a sensitivity of 99%, specificity of 86%, positive predictive value of 87% and negative predictive value of 99%. The results indicate that the dot-ELISA rapid test using recombinant 56-kDa protein antigen may be very useful for the diagnosis of scrub typhus in hospitals where IFA are not available and that the recombinant 56-kDa protein antigens could be used for the dot-ELISA technique.