Context: Cystic echinococcosis (CE) caused by Echinococcus granulosus is a disease of a significant burden in India. The World Health Organization recommends the use of hospital data for population surveillance to measure the prevalence of CE.
Aim: The aim of this study was to estimate the seroprevalence of CE and to compare with previous prevalence rates to estimate the changing pattern in seroprevalence of CE.
Materials and methods: A retrospective analysis of laboratory data of 3929 clinically and/or radiologically suspected cases of CE was carried out for 12 years from 2004 to 2015 and compared to the previous data from 1984 to 2003. The seroprevalence of anti-hydatid immunoglobulin G (IgG) was assessed by enzyme-linked immune sorbent assay. Casoni's intradermal skin test and microscopy on aspirated hydatid cyst fluid were also done. The statistical significance was assessed using Chi-square test and Fisher's t-test.
Results: Of the 3929 samples, 1124 (28.6%) were positive for specific anti-hydatid IgG antibody response, while of the 121 tested by Casoni's test, 56 (46.3%) were positive. The seropositivity of CE over the period of 12 years is rising. As compared to our previous data from 1984 to 2003, an overall significant increase in seropositivity was observed during 2004-2015 (28.6% vs. 15.0% in 1984-2003, P < 0.0001).
Conclusions: This study emphasizes the necessity of continuous surveillance and integrated control measures to prevent CE in humans and livestock across the country.
Keywords: Casoni's test; India; echinococcosis; epidemiology; seroprevalence; zoonosis.