Epidemiology and clinical characteristics of alveolar echinococcosis in India: A systematic review and individual participant data meta-analysis.

BACKGROUND

Alveolar echinococcosis (AE) is a life-threatening parasitic disease caused by Echinococcus multilocularis, often misdiagnosed as malignancy. Though historically considered non-endemic in India, recent reports suggest an emerging trend, particularly in Kashmir. The lack of systematic data on Indian AE cases has limited our understanding of its epidemiology warranting a systematic description of Indian AE cases.

METHODS

We performed an individual participant data meta-analysis (IPD-MA) of published AE cases in India. A comprehensive literature search across PubMed, Embase, Web of Science, Scopus and ProQuest, identified 19 studies reporting AE cases in India. Of these, 17 provided individual patient data for meta-analysis, comprising 39 cases. Data on demographics, clinical presentation, radiology, histopathology, serology, treatment, and outcomes were analyzed. Additionally, aggregate data from two studies without IPD-MA were incorporated to estimate the total national caseload.

RESULTS

The median age of patients was 36 years, with a slight female predominance (48.7 %). Kashmir accounted for most cases (64.1 %). The liver was the most affected organ (79.5 %), followed by rare spinal and cerebral involvement. Abdominal pain was the predominant symptom (56.4 %). WHO-IWGE radiological staging classified most cases as advanced AE (stages IIIa/IIIb). Histopathological confirmation was available in 56.4 % of cases, and serological evidence was positive in 59 %. Anti-helminthic therapy (74.3 %) showed better outcomes (p = 0.002), though combination therapy with albendazole and praziquantel did not confer added benefit (p = 0.547). Surgical intervention was performed in 74.2 % but was not significantly associated with improved prognosis (p = 0.952). Mortality was 7.2 %, with a median follow-up of 12.5 months. Aggregate data revealed a total of 110 AE cases reported from India.

CONCLUSIONS

AE is increasingly reported from India, particularly in Kashmir, suggesting a possible local transmission cycle. Given the limited data on reservoir hosts, further ecological and veterinary studies are warranted. A national registry and One Health approach are essential for surveillance and control.