Giardiasis as a neglected disease in Brazil: Systematic review of 20 years of publications.

Introduction: Giardiasis is an intestinal infection that affects more than two hundred million people annually worldwide; it is caused by the flagellated protozoan Giardia duodenalis. In tropical countries and in low or middle-income settings, like Brazil, its prevalence can be high. There is currently no systematic review on the presence of G. duodenalis in patients, animals or water sources in Brazil. Methods: This systematic review was performed according to recommendations established by Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). As databases for our searches, we have used PubMed, Embase, Scopus and the Brazilian database SciELO using the keywords «Giardia*» and «Brazil». Results: This systematic review identified research studies related to G. duodenalis in water, giardiasis in animals, prevalence of giardiasis across Brazilian regions, genotyping of strains isolated in humans, and giardiasis in indigenous populations. We also propose a network of G. duodenalis transmission in Brazil based on genotypes analyses. Conclusion: This is the first time within the last twenty years that a review is being published on the occurrence of G. duodenalis in Brazil, addressing relevant issues such as prevalence, molecular epidemiology and analytical methods for parasite detection. Non-technical summary: Giardiasis is an intestinal disease that affect millions of people worldwide, including children. Its main route of transmission is by ingestion of food or water contaminated with the protozoan G. duodenalis. Transmission does not require an animal host, although transmission from animals to human (zoonotic transmission) has been confirmed as an important vector of human giardiasis. This study is a comprehensive description of the impact of giardiasis in Brazil based on studies published in the country from the past 20 years. We describe Giardia prevalence in humans (including indigenous populations), animals and water supplies. In addition, we create a transmission network model for the disease, based on genotype data previously identified in animal and human hosts as well as in environmental samples. The data compiled here will be useful for design of policies to prevent giardiasis transmission in Brazil. [ABSTRACT FROM AUTHOR]