Giardiainfections in Cuban children: the genotypes circulating in a rural population

Abstract

Stool samples containing Giardia duodenalis cysts were collected from 95 primary-school children in central Cuba, and preserved by storing at -20 degrees C in 70% ethanol. Clinical data were collected for each child. Although 57% of the children were asymptomatic, the remaining 43% each reported between one and three symptoms. Following cyst quantification and isolation, molecular analyses were attempted on all cyst isolates, with the focus on the parasite's beta-giardin and glutamate-dehydrogenase (gdh) genes. Unfortunately, the cyst-preservation procedure appeared to have a deleterious effect on the cysts, since genotyping data could only be obtained for 20 of the 95 isolates. These data indicated, however, an approximately equal distribution between assemblage A (nine isolates) and assemblage B (11 isolates). Children found to be excreting relatively large numbers of cysts were more likely to be symptomatic than children who were excreting fewer cysts, and children with Giardia isolates from assemblage B were more likely to have symptomatic infections than children with isolates from assemblage A. Although considerable sequence variability was seen in the assemblage-B isolates, the assemblage-A isolates were relatively genetically homogeneous. This is the first publication from the Caribbean in which the Giardia genotypes circulating within the population have been identified, the first from the Americas providing information on associations between clinical presentation and the assemblage of the infecting Giardia, and the first to indicate that levels of cyst excretion may have clinical significance.

Zoonotic Potential and Molecular Epidemiology ofGiardiaSpecies and Giardiasis

“…Likewise, in elementary school children in Saudi Arabia, all infections with assemblage B were symptomatic, while only subassemblages AI and AII were found in asymptomatic infections (12). It was also noticed that symptomatic giardiasis was more significantly associated with assemblage B in children and adults in Ethiopia (87) and elementary school children in Cuba (202).…”

“…High infection rates for giardiasis have been reported for developing countries, and some recent data are listed in Table 2. In various Asian countries (Bangladesh, Cambodia, China, India, Indonesia, Laos, Malaysia, Nepal, Philippines, Thailand, Turkey, Saudi Arabia, and Vietnam), North America (Cuba, Mexico, and Nicaragua), South America (Argentina, Brazil, Colombia, and Peru), and Africa (northern Africa, west Africa, and South Africa), most of the studies focused on children, and infection rates for G. duodenalis fell into the range of 8% to 30% in the majority of those studies (12,29,56,62,63,65,69,144,160,166,174,184,186,202,203,229,234,237,239,252,253,281). In a few studies, the infection rate was lower than 4% or higher than 30% (65,137,145,230,243,274,280).…”

Genotyping of Giardia duodenalis Cysts by New Real-Time PCR Assays for Detection of Mixed Infections in Human Samples

“…The severity of the disease is likely determined by the interplay between the parasite virulence and the developmental, nutritional, and immunological status of the host. Studies conducted until now have been discordant; some authors have reported an association between assemblage A and symptoms (2,16,28,30,31), while others have pointed to an association between assemblage B and symptoms (12,18,29). Almost all of these studies were based on the analysis of a single gene, and it is interesting that genotyping at the ssu-rRNA and tpi genes supports the assemblage A-symptoms association, whereas genotyping at the ␤-giardin and gdh genes supports the assemblage B-symptoms association.…”

Genotipos de Giardia duodenalis en niños de las guarderías del Instituto Colombiano de Bienestar Familiar y de caninos en Ibagué, Tolima, Colombia

“…Este resultado concuerda con lo observado en otros países americanos, como Nicaragua, Brasil, Perú y Argentina (19,26,31,32), en donde se han encontrado también los dos genotipos circulando entre los aislamientos provenientes de las personas analizadas, con valores equiparables a los hallados en Cuba, con nueve aislamientos del genotipo A (45 %) y 11 del genotipo B (55 %) (33).…”