Abstract

Background: Leptospirosis is an uncommon disease in North India; but with recent increased prevalence, especially in Himachal Pradesh (HP). No prospective information is available from the state of Himachal Pradesh.

Aim & Objectives: To study the phenomenon of Leptospirosis in the North Indian state of Himachal Pradesh and thereby (i) determine its prevalence amongst patients with Fever of Unknown Origin (FUO), (ii) evaluate and understand the clinico-epidemiologic pattern of leptospirosis in HP, and (iii) evaluate the utility of Modified Faine’s Criteria for diagnosing leptospirosis.

Methodology: Prospective study conducted in patients with FUO over a 1-year period (June 2006- May 2007). The patients with a strong clinical suspicion of a diagnosis of leptospirosis were subsequently identified by the treating physicians. Their blood samples subjected to ELISA (as per manufacturer’s instructions) and MAT serology. For the ELISA serology positive cases, Modified Faine’s Criteria were administered to arrive at a presumptive/definitive diagnosis of leptospirosis.

Results: Amongst 100 cases of FUO, 26 % had a high clinical suspicion of leptospirosis. These 26 cases were subjected to IgM ELISA for leptospirosis; 7/26 (27%) testing positive.The 7 MAT samples got contaminated; hence results unavailable. 5/7 patients developed FUO in the rainy season and 2/7 in the non-rainy season. The mean age was 35 years; male to female ratio=1.3:1; all were from a rural background.

The epidemiological and clinical profile had some significant differences to that reported in the earlier reported studies from the same region.

Using Modified Faine’s Criteria, all 7 cases received a presumptive diagnosis of leptospirosis i.e. total score >26 (i.e. 100% Positive Predictive Value). However, without availability of serological measures; 2/7 cases were not receiving the presumptive diagnosis of leptospirosis i.e. false-negative’ value of 28%; these getting rightly diagnosed/classified using Original Faine’s Criteria.

Conclusions: Leptospirosis is not as uncommon in HP as previously thought. There appears to be a possible differing clinico-epidemiological profile that needs further evaluation. There appears to be a role of application of both Original and Modified Faine’s Criteria in non-rainy and rainy regions of HP (and possibly even in other parts of North India). There is a need to carry out epidemiologically designed, large-sample prevalence studies on FUO and leptospirosis utilizing both sets of Faine’s Criteria.

Summary: This study was conducted in the North Indian state of Himachal Pradesh with the aim of finding prevalence of leptospirosis in patients of fever of unknown origin (FUO). FUO is a complex entity with over 200 causes; leptospirosis being one of the important ones. However, leptospirosis is a neglected diagnosis in this part of India due to lack of awareness among physicians and lack of diagnostic modalities. Serology (using IgM ELISA) is the most common method to diagnose leptospirosis, as the microorganism is difficult to cultivate. Clinically, Modified Faine‘s criteria (especially developed for the Indian setting) are useful in diagnosis of leptospirosis. In this study, of 100 cases with FUO, 26 cases with strong clinical suspicion of leptospirosis were subjected to ELISA; 7/26 (27%) were positive. Modified Faine’s criteria were applied to these confirmed 7 cases; only 5/7 met the modified criteria (and 2/7 met the original Faine’s criteria). To conclude, leptospirosis is prevalent in North India, and both the Original and Modified Faine’s criteria may have a role in arriving at a clinical diagnosis for patients presenting from non-rainy and rainy regions respectively.

Keywords: Leptospirosis, Faine’s criteria, India.