Serological evidence for wide distribution of spotted fevers & typhus fever in Tamil Nadu.

TLDR

Spotted fevers and typhus have re‑emerged in southern India, yet community‑based data are scarce and heightened awareness, diagnosis, and treatment are urgently needed. The study aimed to map the distribution of these rickettsial infections across multiple districts of Tamil Nadu. Researchers collected 3‑ml blood samples from febrile patients (>10 days) at 15 primary health centres (Jan 2004‑Dec 2005), excluded malaria cases, and tested them with the Weil‑Felix assay while gathering clinical data from two hospitals. In 2004, 37.5 % of 306 samples were positive for scrub typhus; in 2005, 9.2 % of 964 samples were positive, with an additional 4.6 % for other rickettsial illnesses; most cases occurred in individuals over 14 years, peaked from August onward, and the infections were widely distributed across Tamil Nadu.

Abstract

Although the re-emergence of spotted fevers and typhus was documented from southern India a few years ago, there was a paucity of community based data. Therefore a collaborative study was carried out in several districts of Tamil Nadu to understand the distribution of these infections.Blood (3 ml) was collected from patients presenting to primary health centres (PHCs) with fever >10 days duration in 15 districts of Tamil Nadu during January 2004 to December 2005. Patients negative for malaria, were tested by Weil-Felix test. Clinical data were collected from patients visiting two hospitals.A total 306 samples were tested in 2004 and 115 (37.5%) had titres of >or=80 with OX K antigen, suggesting a diagnosis of scrub typhus. During 2005, 964 patients were tested and 89 (9.2%) were positive for scrub typhus. An additional 44 (4.6%) were positive for other rickettsial illnesses. In both years majority of scrub typhus occurred in individuals above 14 yr of age. Cases increased from August until the earlier part of next year.This community based study from south India involving several districts in Tamil Nadu, showed that scrub typhus and rickettsial illnesses were widely distributed in the State. Measures to increase awareness and also to diagnose and treat this infection in the affected areas are essential.