Diagnosis of intestinal parasites in a rural community of Venezuela: Advantages and disadvantages of using microscopy or RT-PCR.

A cross-sectional study was carried out to determine the prevalence and diagnostic performance of microscopy and real time PCR (RT-PCR) for 14 intestinal parasites in a Venezuelan rural community with a long history of persistent intestinal parasitic infections despite the implementation of regular anthelminthic treatments. A total of 228 participants were included in this study. A multiplex RT-PCR was used for the detection of Dientamoeba fragilis, Giardia intestinalis, Cryptosporidium sp. and a monoplex RT-PCR for Entamoeba histolytica. Furthermore, a multiplex PCR was performed for detection of Ascaris lumbricoides, Strongyloides stercoralis, Necator americanus and Ancylostoma duodenale. Combined microscopy-PCR revealed prevalences of 49.3% for A. lumbricoides, 10.1% for N. americanus (no A. duodenale was detected), 2.0% for S. stercoralis, 40.4% for D. fragilis, 35.1% for G. intestinalis, and 7.9% for E. histolytica/dispar. Significant increases in prevalence at PCR vs. microscopy were found for A. lumbricoides, G. intestinalis and D. fragilis. Other parasites detected by microscopy alone were Trichuris trichiura (25.7%), Enterobius vermicularis (3.4%), Blastocystis sp. (65.8%), and the non-pathogenic Entamoeba coli (28.9%), Entamoeba hartmanni (12.3%), Endolimax nana (19.7%) and Iodamoeba bütschlii (7.5%). Age- but no gender-related differences in prevalences were found for A. lumbricoides, T. trichiura, G. intestinalis, and E. histolytica/dispar. The persistently high prevalences of intestinal helminths are probably related to the high faecal pollution as also evidenced by the high prevalences of non-pathogenic intestinal protozoans. These results highlight the importance of using sensitive diagnostic techniques in combination with microscopy to better estimate the prevalence of intestinal parasites, especially in the case of D. fragilis trophozoites, which deteriorate very rapidly and would be missed by microscopy. In addition, the differentiation between the pathogenic E. histolytica and the non-pathogenic E. dispar can be attained. However, microscopy remains an important diagnostic tool since it can detect other intestinal parasites for which no PCR is available.

High malnutrition rate in Venezuelan Yanomami compared to Warao Amerindians and Creoles: significant associations with intestinal parasites and anemia.

BACKGROUND: Children in rural areas experience the interrelated problems of poor growth, anemia and parasitic infections. We investigated the prevalence of and associations between intestinal helminth and protozoan infections, malnutrition and anemia in school-age Venezuelan children. METHODS: This cross-sectional study was conducted in 390 children aged 4-16 years from three rural areas of Venezuela: the Amazon Region, Orinoco Delta and Carabobo State. Stool samples were collected for direct parasitic examinations. Anthropometric indicators of chronic (height-for-age Z score) and acute (weight-for-height and Body Mass Index (BMI)-for-age Z score in respectively children under 5 years of age and children aged 5 years and above) malnutrition were calculated. Multivariate linear and logistic regression models were built to determine factors associated with nutritional status and polyparasitism. RESULTS: Hookworm and Strongyloides stercoralis prevalences were highest in children from the Amazon rainforest (respectively 72% and 18%) while children from the Orinoco Delta and Carabobo State showed higher rates of Ascaris lumbricoides (respectively 28% and 37%) and Trichuris trichiura (40% in both regions). The prevalence of Giardia lamblia infection was not significantly different between regions (average: 18%). Anemia prevalence was highest in the Amazon Region (24%). Hemoglobin levels were significantly decreased in children with a hookworm infection. Malnutrition was present in respectively 84%, 30% and 13% of children from the Amazon Region, Orinoco Delta and Carabobo State. In multivariate analysis including all regions, G. lamblia and helminth infections were significantly and negatively associated with respectively height-for-age and weight-for-height/BMI-for-age Z scores. Furthermore, hemoglobin levels were positively associated with the height-for-age Z score (0.11, 95% CI 0.02 - 0.20). CONCLUSIONS: In rural populations in Venezuela helminthiasis and giardiasis were associated with acute and chronic nutritional status respectively. These data highlight the need for an integrated approach to control transmission of parasites and improve the health status of rural Venezuelan children.

Zoonotic parasites in fecal samples and fur from dogs and cats in The Netherlands.

Pets may carry zoonotic pathogens for which owners are at risk. The aim of the study is to investigate whether healthy pets harbour zoonotic parasitic infections and to make an inventory of the interactions between pet-owners and their companion animals in The Netherlands. Fecal and hair samples were collected from healthy household dogs and cats in Dutch veterinary practices. Owners were interviewed about interaction with their pets. The samples were investigated by microscopy, ELISA, and PCR. From 159 households, 152 dogs (D) and 60 cats (C), information and samples were collected and examination for several zoonotic parasites was performed. Toxocara eggs were found in 4.4% (D) and 4.6% (C) of the fecal samples and in 12.2% (D) and 3.4% (C) of the fur samples. The median epg in the fur was 17 (D) and 28 (C) and none of these eggs were viable. From 15.2% of the dog and 13.6% of the cat feces Giardia was isolated. One canine and one feline Giardia isolate was a zoonotic assemblage A (12%). Cryptosporidium sp. were present in 8.7% (D) and 4.6% (C) of the feces. Fifty percent of the owners allow the pet to lick their faces. Sixty percent of the pets visit the bedroom; 45-60% (D-C) are allowed on the bed, and 18-30% (D-C) sleep with the owner in bed. Six percent of the pets always sleep in the bedroom. Of the cats, 45% are allowed to jump onto the kitchen sink. Nearly 39% of the dog owners never clean up the feces of their dog. Fifteen percent of the dog owners and 8% of the cat owners always wash their hands after contact with the animals. Close physical contact between owners and their pets is common and poses an increased risk of transmission of zoonotic pathogens. Education of owners by the vet, specifically about hygiene and potential risks, is required.