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

Abstract

BackgroundIntestinal protozoan parasites are major contributors to the global burden of gastrointestinal disease causing significant socioeconomic consequences. Children living in resource-poor settings with restricted access to water and sanitary services are particularly at risk of these infections.MethodsA prospective, community-based, cross-sectional survey was conducted in Paraná (southern Brazil) between May 2015 and May 2016. A total of 766 stool samples were individually collected from volunteers (male/female ratio: 0.99; age range: 0–76 years) and used for investigating the presence of intestinal helminth and protozoan species by routine microscopic procedures including the Kato-Katz and modified Ritchie concentration methods and the Ziehl-Neelsen stain technique. Quantitative real-time PCR confirmed microscopy-positive samples for Giardia duodenalis and the assemblages and sub-assemblages determined by multilocus sequence-based genotyping of the glutamate dehydrogenase (gdh) and β-giardin (bg) genes of the parasite. Identification of Blastocystis subtypes was carried out by amplification and sequencing of a partial fragment of the small-subunit ribosomal RNA gene (SSU rDNA) of this heterokont microorganism.ResultsOverall, 46.1% (353/766) of the participants were infected/colonised by at least one intestinal parasite/commensal species. Protozoan and helminth species were detected in 42.7% and 10.1% of the surveyed population, respectively. Blastocystis sp. (28.2%), Endolimax nana (14.9%), and Giardia duodenalis (11.0%) were the most prevalent species found among protozoans and Ascaris lumbricoides (5.0%), Trichuris trichiura (4.6%) and hookworms (1.0%) among helminths. A total of 38 G. duodenalis-positive samples were genotyped at gdh and bg markers, revealing the presence of the sub-assemblages AII (47.4%), AII/AIII (2.6%), BIII (5.3%), BIV (26.3%) and BIII/BIV (13.1%). Two samples (5.3%) were only identified as assemblage B. AII was predominantly found in females aged 5–9 years and was associated with a higher likelihood of reporting gastrointestinal symptoms. A total of 102 Blastocystis-positive samples were successfully subtyped at the SSU rRNA gene revealing the presence of ST1 (36.3%), ST2 (15.7%), ST3 (41.2%), ST4 (2.9%), ST6 (1.0%) and ST8 (2.9%).ConclusionsData presented here indicate that enteric parasites still represent a pressing health concern in Paraná, Brazil, probably due to sub-optimal water, sanitation and hygiene conditions. A mostly anthroponotic origin is suspected for G. duodenalis and Blastocystis sp. infections.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3054-7) contains supplementary material, which is available to authorized users.

Genetic analysis of Giardia duodenalis isolates from children of low-income families living in an economically successful region in Southeastern Brazil

“…The occurrence of assemblages A and B is not surprising considering that to date, these groups have been frequently found in humans and animals infections worldwide 1,34 . The predominance of assemblage A corroborates the results of other studies in Brazil 6,25,35 , Malaysia 36 , Ethiopia 37 and Slovakia 20 . In contrast, a higher prevalence of assemblage B has been reported in children in Brazil 8,38 and in other countries 39,40 .…”

“…This frequency was lower than those recently reported in daycare and preschool children living in communities of São Paulo State, some of them placed in regions near the study area 8,16,17 . Recently, the examination of one fecal sample has revealed Giardia infection rates ranging from 2.7% to 11% in children of preschool age in some surveys worldwide [18][19][20][21] , including Brazil [22][23][24][25] . Even when the diagnosis is based on the examination of three stool samples, the studies did not report much higher prevalence rates 8,9,16,17 .…”

First Report on the Prevalence and Subtype Distribution of Blastocystis sp. in Edible Marine Fish and Marine Mammals: A Large Scale-Study Conducted in Atlantic Northeast and on the Coasts of Northern France

“…Among these isolates, five of them identified in herring and saithe exhibited 100% sequence identity with each other and were classified as ST8. Indeed, the SSU rDNA sequence of these isolates exhibited 100% identity with those of several ST8 isolates identified from humans and animal hosts in different countries [16,33,34]. As reported in a recent epidemiological survey conducted in zoos and compiling available data from the literature [16], ST8 has been almost exclusively identified in non-human primates, to a lesser extent in marsupials and episodically in human beings in relation to a likely zoonotic transmission [16].…”

Prevalence and associated risk factors of Intestinal parasites in rural high-mountain communities of the Valle del Cauca—Colombia

“…(28,2%), Endolimax nana (14,9%), and Giardia duodenalis (11%) with similar frequencies as reported in this study. It is important to add that guard association with rotavirus and cryptosporidium is frequent [ 32 ]. The presence of Dipylidium caninum (12%) found in this study in dogs has been previously reported as a zoonosis in children [ 33 ], but no cases associated with the child population were found in these communities.…”