Identical Assemblage of Giardia duodenalis in Humans, Animals and Vegetables in an Urban Area in Southern Brazil Indicates a Relationship among Them

Abstract

Background Giardia duodenalis infects humans and other mammals by ingestion of cysts in contaminated water or food, or directly in environments with poor hygiene. Eight assemblages, designated A–H, are described for this species.Methodology/Principal FindingsWe investigated by microscopy or by direct immunofluorescence technique the occurrence of G. duodenalis in 380 humans, 34 animals, 44 samples of water and 11 of vegetables. G. duodenalis cysts present in samples were genotyped through PCR-RFLP of β giardin and glutamate dehydrogenase (gdh) genes and sequencing of gdh. The gdh gene was amplified in 76.5% (26/34) of the human faeces samples with positive microscopy and in 2.9% (1/34) of negative samples. In 70.4% (19/27) of the positive samples were found BIV assemblage. In two samples from dogs with positive microscopy and one negative sample, assemblages BIV, C, and D were found. Cysts of Giardia were not detected in water samples, but three samples used for vegetable irrigation showed total coliforms above the allowed limit, and Escherichia coli was observed in one sample. G. duodenalis BIV was detected in two samples of Lactuca sativa irrigated with this sample of water. BIV was a common genotype, with 100% similarity, between different sources or hosts (humans, animals and vegetables), and the one most often found in humans.Conclusions/SignificanceThis is the first study in Brazil that reports the connection among humans, dogs and vegetables in the transmission dynamics of G. duodenalis in the same geographic area finding identical assemblage. BIV assemblage was the most frequently observed among these different links in the epidemiological chain.

Giardia duodenalis in small animals and their owners in Germany: A pilot study

“…Nevertheless, we detected canine samples with potentially human‐pathogenic assemblages AI and B, which corresponds to previous studies (Berrilli et al, ; Colli et al, ; Lalle et al, ; Marangi et al, ; Souza et al, ). In addition, three of the (asymptomatic) humans tested positive and two of these humans owned dogs, which were also Giardia ‐positive.…”

Prevalence of intestinal parasites, with emphasis on the molecular epidemiology of Giardia duodenalis and Blastocystis sp., in the Paranaguá Bay, Brazil: a community survey

“…Remarkably, multiple sequence alignment analyses demonstrated that some of our BIV sequences were identical (e.g. KJ741322 vs MG807891) with those described by Colli et al [51]. Taken together, these data strongly suggest that transmission of G. duodenalis in Paraná is primarily anthroponotic, either directly through contact with infected individuals or asymptomatic carriers or indirectly through ingestion of contaminated food/water.…”

Predominance of Giardia duodenalis Assemblage AII in Fresh Leafy Vegetables from a Market in Southern Brazil

“…However, the immunochemical detection methods were important to reestablish the comparisons between the techniques once they had been used for more time in environmental studies (3,12,21).…”

“…Little is known about the geographical distribution of zoonotic genotypes A and B in Brazil (3,4,11,17,28). In this context, the presence of G. duodenalis and its respective genotypes was investigated in vegetables that are consumed raw and sold in a market known as ''market of the Maringá producer,'' which is distinct from most street markets of Brazil because the producers themselves display and sell their produce, and their business has relied upon technical and sanitary assistance at various levels of production and distribution for at least 20 years.…”