An outbreak of acute skin and soft tissue infections including necrotizing fasciitis in Kalwala village, India, 2018: Public health implications for the lymphatic filariasis elimination program

Background A cluster of 15 acute skin and soft tissue infections (SSTIs), including two cases of necrotizing fasciitis, reported in July 2018 from Kalwala village, led us to investigate and describe their epidemiology and to provide recommendations. Methods Cases, defined as localized painful swelling and redness in Kalwala residents from 1 December 2017 to 20 August 2018, were identified from hospital records and house-to-house surveys. We conducted an unmatched case-control study to identify risk factors for severity. We cultured wound samples and environmental samples from wound-dressing stations. Results We identified 36 cases (median age: 55 [range 17–80] y; 78% male), village attack rate 1% (36/4337) and no deaths. In 34 cases (94%), lower limbs were involved. Lymphatic filariasis (LF) was a common predisposing condition (67%). Comorbidities (diabetes or hypertension) (OR=9; 95% CI 2.0 to 41.1), poor limb hygiene (OR=16; 95% CI 2.8 to 95.3) and poor health-seeking behavior (OR=5; 95% CI 1.6 to 30.8) were associated with severity. All seven wound samples and 8/11 samples from wound-dressing stations showed atypical polymicrobial growth (Pseudomonas, Proteus, Klebsiella, Escherichia coli and Clostridium). Conclusion The outbreak of SSTIs among older males with LF was due to secondary bacterial infections and severity was associated with comorbidities, poor hygiene and health-seeking behavior, and likely contamination during wound-dressing. The LF elimination program managers was alerted, programmatic interventions were scaled up, home/facility-based morbidity and comorbidity management was facilitated and the outbreak was rapidly contained.