Molecular appraisal of Giardia intestinalis from Western India: A prospective observational study

Giardia intestinalis is an intestinal protozoan which commonly causes parasitic gastroenteritis globally. It is a species complex consisting of at least eight assemblages (genotypes). In India, Giardia is mostly underreported and missed in asymptomatic cases.

The aim of this study was to genotype the G. intestinalis isolates from stool samples of patients at a tertiary care center in Rajasthan, India, and to clinically correlate it.

This prospective pilot cross-sectional study was conducted from 2019 to 2021 in a tertiary care center in western India. Patients who were microscopically positive for giardiasis were enrolled. DNA was extracted from their stool samples and amplified by polymerase chain reaction (PCR) using 4E1-HP as the target sequence. Anthropometric measurements and analysis were done for children by using Anthrocal application.

A total of 50 patients were enrolled. Diarrhea was present in 18 patients (36%). Among these, 6 were immunocompromised and had different comorbidities. Among the children <12 years of age, 55.17% (n = 16/29) were stunted (<-2 S.D.), and among <5 years, 44.4% (n = 4/9) showed wasting (<-2 S.D.). A PCR product corresponding to assemblage B of G. intestinalis was amplified in 47 stool specimens. Only three stool samples were negative for both assemblages A and B and posed an interesting enigma.

In this study, a predominance of assemblage B of G. intestinalis was detected in 94% of the isolates. Furthermore, the possibility of zoonotic transmission could not be ruled out.