Prevalence and Genetic Diversity of Giardia duodenalis in Africa: A Review.

Abstract

Introduction: Enteric parasites are the primary cause of diarrheal diseases and other gastrointestinal clinical presentations in Africa and some parts of the world. Giardia duodenalis causes giardiasis in most African countries and poses considerable public health concerns.

Objective: This review was aimed at synchronizing data on the genetic diversity of G. duodenalis and its prevalence across Africa.

Methods: Thorough searches were performed in the following electronic databases: Medline/PubMed, Web of Science, Scopus, ScienceDirect, and Google Scholar. The search technique encompassed terms associated with "G. duodenalis", "Africa", "genetic", "Genetic diversity", "Assemblage", "Sub-assemblage", and "Lamblia".

Results: This review shows that 83% (10/12) of the studies considered children as the study population, while 16.7% (2/12) recruited apparently healthy adults. A total of 914 positive cases were genotyped, primarily employing genetic loci such as bg (beta giardin), tpi (triose phosphate isomerase), and gdh (glutamate dehydrogenase). All the studies identified the two main human assemblages of G. duodenalis, notably Assemblage A and B, with five out of 12 identifying mixed infections of Assemblages A and B. This review revealed G. duodenalis Assemblage A in 22.6% (207/914) of cases using specific Giardia assemblage primers. Assemblage B was found in 70% (640/914) of cases, and mixed infection with A and B assemblages was seen in the remaining cases at 6.7% (61/914). The review showed a 31.9% prevalence of G. duodenalis and giardiasis across Africa.

Conclusion: The findings of this review suggest a relatively high prevalence of G. duodenalis infections in Africa. There is also significant genetic diversity of G. duodenalis across regions in sub-Saharan Africa, with Assemblage B being the most dominant.