Nested polymerase chain reaction on blood clots for gene encoding 56 kDa antigen and serology for the diagnosis of scrub typhus.

Purpose : Scrub typhus is a zoonotic illness endemic in the Asia-Pacific region. Early diagnosis and appropriate management contribute significantly to preventing adverse outcomes including mortality. Serology is widely used for diagnosing scrub typhus. Recent reports suggest that polymerase chain reaction (PCR) could be a rapid and reliable alternative. This study assessed the utility of these tests for scrub typhus diagnosis. Materials and Methods : Nested PCR to detect the 56 kDa antigen gene of O. tsutsugamushi was performed on blood clots from 87 individuals with clinically suspected scrub typhus. Weil-Felix test and scrub typhus IgM ELISA were performed on serum samples from the same patients. As a gold standard reference test was not available, latent class analysis (LCA) was used to assess the performance of the three tests. Results : The LCA analysis showed the sensitivity of Weil-Felix test, IgM ELISA and PCR to be 59%, 100% and 58% respectively. The specificity of ELISA was only 73%, whereas those of the Weil-Felix test and PCR were 94% and 100% respectively. Conclusion : Nested PCR using blood clots while specific, lacked sensitivity as compared to IgM ELISA. In resource-poor settings Weil-Felix test still remains valuable despite its moderate sensitivity.

Audit of management of pregnant women with positive VDRL tests.

BACKGROUND: Syphilis is a preventable cause of foetal loss and congenital disease. Although the VDRL test is an integral part of routine antenatal care in India, little is known about the disease burden in pregnancy in India. Therefore, we carried out a study to determine the prevalence of VDRL positivity and syphilis among pregnant women in Vellore and to audit the management and outcome of VDRL-positive pregnancies. METHODS: A retrospective review of case records. RESULTS: Only 0.98% of pregnant women were positive by the VDRL test. However, foetal loss occurred in 16 (32%) of the 50 seropositive women; 15 of these did not receive antenatal care. Seventeen of the 34 seropositive multiparous women had had previous foetal losses. Only 16 women had received penicillin. CONCLUSION: Although the seroprevalence of syphilis in pregnancy is low, it is an unrecognized cause of foetal loss in Vellore. An audit of the testing and management of VDRL positivity in pregnancy provides valuable information on the quality of antenatal care in an area.