Genotypic and Epidemiologic Profiles of Giardia duodenalis in Four Brazilian Biogeographic Regions

Gut protozoan parasites are neglected and not targeted by specific control initiatives and this have led to a knowledge gap concerning their regional diversity and epidemiology. The present study aims to explore Giardia duodenalis genetic diversity and assess the epidemiologic scenario of subclinical infections in different Brazilian biogeographic regions. Cross-sectional surveys (n=1,334 subjects) were conducted in the Amazon, Cerrado, Semiarid and Atlantic Forest. Microscopy of non-diarrheal feces and nucleotide sequencing of a β-giardin gene fragment were performed. Twenty-seven (52.9%) β-giardin sequences were characterized as assemblage A and 24 (47.1%) as assemblage B. In Amazon, assemblage B was the most frequently detected with 2 novel sub-assemblages. Assemblage A predominated in the extra-Amazon region, with 5 novel sub-assemblages. Prevalence rates reached 17.8% in Amazon, 8.8% in Atlantic Forest, 7.4% in Cerrado and 2.3% in the Semiarid. People living in poverty and extreme poverty presented significantly higher positivity rates, reaching 11.9% and 14.5%, respectively. Giardiasis tended to be more frequent in stunted (21.6%) than in eutrophic children (12.9%). In conclusion, subclinical giardiasis in endemic in Brazilian communities in different biogeographic regions, presenting high genetic diversity and a heterogeneous genotypic distribution.