Emerging visceral leishmaniasis patients in mid Southern Himalayan region: A public health concern

Visceral leishmaniasis (VL, or Kala-azar) is a potentially lethal vector-borne disease caused by intracellular protozoa of the genus Leishmania , serves as the primary reservoir; traditionally endemic to Bihar, Jharkhand, West Bengal, and Eastern Uttar Pradesh Indian states along river belts. VL has recently been observed in the past few years at a tertiary care teaching hospital located in the Himalayan region (non-endemic state, Uttarakhand). This study was done to identify the clinical features, demographics, complications and the risk factors involved in patients of non-endemic region a tertiary care hospital.

This retrospective study with present-day follow-up of all patients was done on VL patients who were admitted from January 2018 to January 2024. Diagnosis was established by rK 39 antigen test and/or Leishman-Donovan (LD) bodies on bone marrow examination. The clinical and laboratory data, duration of hospital stay and outcomes, and associated risk factors were collected on a proforma and analysed. Factors associated with Himalayan region (Uttarakhand) above Rishikesh (>1120 feet from sea level) were analysed using Chi-square.

Males constituted 92% of the study population from which 67% of the population was from the Himalayan region of this middle Southern Himalaya (Uttarakhand). Risk factors such as residence in the rural area (p=0.47), residence near vegetation (p=0.12), poor household characteristics (p=0.073), low educational status (p=0.073), nearby water body (p=0.073), poor sewage or garbage disposal (p=0.241), insect bites (p=0.040) were associated with Himalayan region emergence. Fever (100%) and malaise (100%) were the most common symptoms presented followed by pain abdomen (29%). Pallor (100%) and splenomegaly (100%) were the most common abnormalities identified on examination followed by hepatomegaly (83%). Anemia (100%) and leukopenia (100%) were the most common biochemical abnormality detected followed by thrombocytopenia (79%), acute liver injury (63%), and hemophagocytic lymphohistiocytosis (HLH) (58%). The disease was diagnosed by the rK39 antigen test (67%), LD bodies in bone marrow examination (67%) and both positive in 29% patients. Mortality was seen in 17 % patients secondary to sepsis (75%) and one case post-discharge due to unknown reasons.

VL is emerging in Himalayan (Uttarakhand) region and has been found to have higher mortality and organ involvement (hepatomegaly) compared to non-Himalayan region. This calls for initiating a surveillance program before declaring elimination/eradication.