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.

A concomitant study was carried out, of the association of positive serology for Toxocara spp. in 90 children who played in public squares used for leisure, with the frequency with which each child used these areas, and the presence of eggs of Toxocara spp. in the sand or grass in these locations. The sand and grass of their peridomiciles and school playgrounds, as well as the feces of their dogs were also analyzed for Toxocara. Serum samples were tested for IgG antibodies to Toxocara canis excreted-secreted larval antigens by ELISA, and blood samples for eosinophilia. The water-sedimentation technique was used to evaluate the presence of parasite eggs in the sand and grass turfs, and in feces of the dogs that also frequented these locations. 16/90 (17.8%) of the children were seropositive for Toxocara spp. There was a positive association between seropositivity in children who played in the public squares six or seven times a week, with a parasite load above 1.1 eggs/g of sand, as well as with contamination of the peridomicile, even at less than 1.0 egg/g of sand. Eosinophilia, the habit of geophagy, age from one to four years, and the presence of parasitized pet dogs were also positively correlated with seropositivity in the children. Eggs were found in 15/15 (100%) of the public squares, 17/90 (18.9%) of the peridomiciles, 3/13 (23.1%) of the schools, and 12/41 (29.3%) of the dogs living in the peridomiciles investigated.

SUMMARYToxocariasis is a worldwide public-health problem that poses major risks to children who may accidentally ingest embryonated eggs of Toxocara. The objectives of this study were to investigate the occurrence of anti-Toxocara spp. antibodies in children and adolescents and the variables that may be involved, as well as environmental contamination by Toxocara spp. eggs, in urban recreation areas of north central mesoregion, Paraná State, Brazil. From June 2005 to March 2007. a total of 376 blood samples were collected by the Public Health Service from children and adolescents one to 12 years old, of both genders. Samples were analyzed by the indirect ELISA method for detection of anti-Toxocara antibodies. Serum samples were previously absorbed with Ascaris suum antigens, and considered positive with a reagent reactivity index ≥1. Soil samples from all of the public squares and schools located in the four evaluated municipalities that had sand surfaces (n = 19) or lawns (n = 15) were analyzed. Of the 376 serum samples, 194 (51.6%) were positive. The seroprevalence rate was substantially higher among children aging one to five years (p = 0.001) and six to eight years (p = 0.022). The clinical signs and symptoms investigated did not show a statistical difference between seropositive and seronegative individuals (p > 0.05). In 76.5% of the investigated recreation places, eggs of Toxocara were detected in at least one of the five collected samples. Recreation areas from public schools were 2.8 times more contaminated than from public squares. It is important to institute educational programs to inform families and educators, as well as to improve sanitary control of animals and cleaning of the areas intended for recreation in order to prevent toxocariasis.

The objectives of this study were to evaluate the contamination by eggs of Toxocara in sandy areas or grass lawns of outdoor recreation areas that are used by children, and the frequency of seroprevalence in children, from three cities of fewer than 45,000 inhabitants in Paraná, Brazil. From May 2005 to December 2007, five samples were taken from each of 13 sandy sites and 18 grass lawns, all from plazas and public schools. Blood samples from children aged 0-12 years were analysed by immunoassay for anti-Toxocara IgG. The soil samples were processed by floatation and sedimentation. Eggs of Toxocara spp. were present in 44.7% (38/85) of the samples from grassed areas and in 21.4% (15/70) of the sand samples. The lawns were 2.16 times more contaminated than the sand (P = 0.0009). However, the epidemiological variables showed no statistically significant difference between seropositive (36.8%; 130/353), and seronegative children. The rate of seropositivity was higher in children aged 0-5 years (P = 0.03), who were 1.94 times more likely to develop persistent wheezing (P = 0.02).

Despite the high dispersion of Toxoplasma gondii oocysts in the environment, there are few studies investigating their presence in vegetables consumed by the general population. This has led us to investigate its occurrence in raw vegetables. A total of 238 samples of vegetables were collected, including crisp lettuce, regular lettuce, chicory, rocket, and parsley, both organic and nonorganic, locally in northwestern Parana, Southern Brazil. Each sample (50 g) was washed and filtered separately. A PCR was performed to detect the parasite DNA from the sediment of each sample, using B1 (B22-23) and Toxo4-5 primers. We found contamination in 3.8% of the samples, 0.8% with the primer Toxo4-5 and 2.9% with B22-B23. The results were positive in 0.6% (1/62) of the samples of smooth lettuce, 3.7% (4/106) of crisp head lettuce, 5.0% (2/40) of chicory, 14.3% (1/7) of rocket, and 20% (1/5) of parsley. These data show the contamination by T. gondii in raw vegetables directly from production sites and stores, in both organic and nonorganic samples.