Frequency of Blastocystis hominis and other intestinal parasites in stool samples examined at the Parasitology Laboratory of the School of Pharmaceutical Sciences at the São Paulo State University, Araraquara

Abstract

Blastocystis homins is a protozoan that causes an intestinal infection known as human blastocystosis. This infection is diagnosed by means of parasitological examination of stools and by permanent staining techniques. The present study was developed to evaluate the frequency of Blastocystis hominis infection among inhabitants of the Araraquara region, State of São Paulo, and to compare different methods for investigating this protozoan in feces samples. Evaluations on 503 stool samples were performed by means of direct fresh examination and using the techniques of Faust et al., Lutz and Rugai et al. In addition, the iron hematoxylin, trichrome and modified Kinyoun staining techniques were used. Out of the 503 samples examined, 174 (34.6%) were found to be positive for the presence of intestinal parasites. The most frequent protozoa and helminths were Entamoeba coli (14.6%) and Strongyloides stercoralis (6.7%), respectively. Blastocystis hominis was present in 23 (4.6%) fecal samples, with a predominately pasty consistency and without characterizing a condition of diarrhea. Despite the low frequency of Blastocystis hominis found in the Araraquara region, compared with other regions of Brazil, it is important to perform laboratory diagnostic tests for this protozoan. Its finding in fecal material is indicative of food and drinking water contamination. Since the transmission route for this parasite is accepted to be oral-fecal, this implies that the population needs guidance regarding hygiene and basic sanitation measures as a means for controlling health problems caused by enteroparasites. Key-words:Blastocystis hominis. Diagnosis. Intestinal parasites. Coproparasitology. RESUMOBlastocystis hominis é um protozoário, causador de infecção intestinal denominada blastocistose humana, cujo diagnóstico é realizado pelo exame coproparasitológico e por meio de técnicas de coloração permanente. Este estudo foi desenvolvido para avaliar a freqüência da infecção por Blastocystis hominis em habitantes da região de Araraquara/SP, bem como comparar diferentes métodos para a pesquisa desse protozoário em amostras de fezes. Foram estudadas 503 amostras de fezes submetidas ao exame direto a fresco, às técnicas de Faust e cols, Lutz e de Rugai e cols, além das colorações pela hematoxilina férrica, tricrômio e de Kinyoun modificada. Entre as 503 amostras examinadas, 174 (34,6%) apresentaram-se positivas para a presença de parasitas intestinais. O protozoário e o helminto mais freqüentes foram Entamoeba coli (14,6%) e Strongyloides stercoralis (6,7%), respectivamente. Blastocystis hominis foi observado em 23 (4,6%) amostras fecais com consistência predominantemente pastosa, não caracterizando quadro diarréico. Apesar da baixa freqüência de Blastocystis hominis encontrada na região de Araraquara, comparativamente a outras regiões brasileiras, é importante a realização do diagnóstico laboratorial desse protozoário. O encontro de Blastocystis hominis em material fecal é indicativo de contaminação de alimentos e água de consumo, ...

Laboratory diagnosis of Blastocystis spp. in diarrheic patients

“…This was in agreement with[ 15 ] who concluded that, trichrome stain was more sensitive for the detection of intestinal protozoa than iodine-stained wet mounts. On the other hand,[ 16 ] reported that, staining with trichrome stain proved to be as efficient as direct examination for confirming the presence of this protozoon in the feces. Dogruman-Al et al ., 2010 reported that using culture as a standard, the sensitivity of iodine-stained smear was 91% and trichrome stain was 100%.…”

Prevalence of Blastocystis sp. infection in several hosts in Brazil: a systematic review and meta-analysis

“…Oliveira-Arbex et al [45] Melo et al [49] David et al [9] Branco et al [58] Miné et al [66] Alarcón et al [68] Kobayashi et al [76] Seguí et al [50] Takizawa et al [64] Borges et al [63] Kulik et al [65] Subtotal (I^2 = 95.61%, p = 0.00) Subtotal (I^2 = 99.28%, p = 0.00)…”

OCCURRENCE OF Blastocystis spp. IN UBERABA, MINAS GERAIS, BRAZIL

“…Intestinal infections by protozoa are frequent all over the world, being most prominent in developing countries, since the majority of the infections are generally acquired by the ingestion of foods or water contaminated by human and/or animal feces, generally caused by the lack of basic sanitation and conditions of hygiene 4 , 6 , 12 . In this context the infection with Blastocystis spp.…”

“…In this context the infection with Blastocystis spp. , an anaerobic intestinal protozoan is one of the most prevalent 6 , 9 , 12 , occurring in approximately 1.5% to 10% of the population in developed countries and 30% to 60% in developing countries 19 . However, these data are underestimated, since laboratory technicians are generally not sufficiently trained to detect it or simply do not report their findings.…”