A study on serodiagnosis of scrub typhus in a Teaching Hospital of South India

Background: crub typhus is caused by Orientia tsutsugamushi(rickettsial disease) commonly transmitted by the bite of larvalchiggers of trombiculid mites. It has been one of the importantcauses of febrile illness, especially in south India. The clinicaldiagnosis is difficult owing to the non-specific presentation.We in the current study tried to evaluate the serodiagnosis ofscrub typhus with the Weil Felix test and IgM ELISA.Methods: This study was conducted in the Department ofMicrobiology, Prathima Institute of Medical Sciences,Naganoor, Karimnagar. All the sera samples were subjected tothe Weil Felix test using Proteus OX2, OX19, OX-K strainagglutination test, and subsequently, Scrub typhus IgM ELISAtest.Results: All the samples were subjected to the Weil Felix testn=4(6.06%) were positive for scrub typhus (OXK antigen)n=11(16.67%) were positive for the spotted group of fever (OX2antigen) and n=10 (15.15%) were positive of typhus group(OX19 antigen). N=5 sera samples were positive for more thanone type of antigens. All the n=66 serum samples weresubjected to IgM ELISA for scrub typhus. Out of n=66, onlytwo serum samples (3.03%) were positive by IgM ELISA.Conclusion: Scrub typhus is emerging as an important publichealth issue. It is one of the important causes of acute febrileillness. Although it is difficult to distinguish scrub typhus basedon the clinical symptoms alone a simple test such as Weil Felixwas found to be promising in the diagnosis of scrub typhus.ELISA IgM test may be performed additionally in laboratorieswith adequate facilities. Hence for clinicians, any case with afever of unknown origin should arouse suspicion of scrubtyphus