Detection of Toxoplasma oocysts from soil by modified sucrose flotation and PCR methods.

A detection method of Toxoplasma gondii oocysts from soil was evaluated using the sucrose flotation technique with modification involving addition of 0.1% gelatin into washing and floating solutions. PCR was performed on untreated samples and after treatment with polyvinylpyrrolidone (PVP), heating and cooling, and NaCl. The addition of gelatin in the sucrose solution yielded a higher number of oocysts. A very thin band was observed when DNA extract was diluted to 1:1024, indicating the presence of PCR inhibitor in the soil. PCR performed on untreated DNA, on PVP-treated, and on PVP-treated with heating and cooling without added bovine serum albumin (BSA) showed a band only at higher dilutions (1:1024 and 1:512) but at a much lower dilution (1:8) with BSA. In contrast, DNA treated with all three agents showed a band at a much lower dilution (1:64), even without added BSA, and no dilution was required when BSA was added. The PCR inhibitors present in the soil were removed by employing various treatment procedures during DNA extraction, and BSA in PCR. Furthermore, the detection limit with the method was 1 oocyst/g of soil, indicating that this method is useful in epidemiological studies.

Epidemiological survey of intestinal parasitic infections of diarrhoeal patients in Nepal and Lao PDR.

Intestinal parasitological survey was conducted to clarify the distribution of intestinal parasites in Nepal and Lao Peoples' Democratic Republic (Lao PDR) from 2001 to 2003. A total of 401 diarrheal fecal specimens were collected from patients aged one to 75 years (250 from Nepal and 151 from Lao PDR). The specimens were examined using the formalin-ether sedimentation (FES) and sucrose centrifugal flotation (SCF) techniques. Nine species (3 Nematoda, 1 Cestoda, and 5 Protozoa) of parasites were recovered from Nepal, whereas seven species (3 Nematoda, 1 Trematoda, and 3 Protozoa) from Lao PDR. Of the parasites detected, (14.4%) was the most common in Nepal, and was Opisthorchis viverrini (29.8%) in Lao PDR. Infection rates were markedly different among age groups in both countries; higher rates were observed in age groups of 10-29 years than in 0-9 years group. Scanning electron microscopic observation revealed that trematoda eggs recovered from Lao PDR were identified as O. viverrini, which could not be done by a light microscope.

Parasites detected from diarrheal stool samples collected in Nepal.

Intestinal parasites were investigated in 396 diarrheal stool samples collected from individuals aged 1 to 68 years (males: 239 and females: 157) in Nepal. Samples were collected at different medical centers located in Kathmandu and from two public schools in a village setting in Kathmandu Valley and outside, during October 1999 to January 2001. The stool samples were mixed with 2% dichromate solution and transported to Japan for investigations. Parasites were detected by employing the formal-ether sedimentation technique. Of a total of 396 fecal samples investigated, 193 (49%) were positive for some kind of parasite. Altogether, 15 species of parasites were detected. Giardia intestinalis topped the list of protozoa, whereas Trichuris trichiura was the most frequently detected among helminth parasites. Of the 193 positive samples, 109 (56%) had single parasite infections, whereas 84 (43%) had multiple infections with a maximum of five species. Of the total positive, 45 (23%) had both protozoa and helminths whereas 37 (19%) had only protozoa. Females (52%) and children (15 years and under) (52%) had a marginally higher prevalence compared with males (46%) and adults (45%), respectively (p > 0.05). Samples collected from two public schools in a village setting inside Kathmandu Valley and outside had a significantly higher positive rate compared with those observed in individuals visiting different medical centers in the city and suburban areas in Kathmandu (p < 0.05).

Intestinal parasitic infections in Bekasi district, West Java, Indonesia and a comparison of the infection rates determined by different techniques for fecal examination.

This study was undertaken to determine the current status of intestinal parasitic infections among schoolchildren in West Java, Indonesia, and to compare the infection rates obtained by three different methods of fecal examination. A total of 285 fecal samples were collected from 131 males and 154 females at a junior high school. Samples were brought to the Department of Parasitology, Faculty of Medicine, University of Indonesia, and were examined for parasites by the Kato-Katz thick smear method (K-K). The residual samples were suspended in more than five volumes of 2% potassium dichromate solution and brought to the Department of Parasitology, Kobe University School of Medicine, Japan, where they were examined for parasites by the Army Medical School method (AMS III) and by the Sucrose Centrifugal Flotation method (SFL). The K-K revealed a total of two helminths with a prevalence of 10% (29/285). In contrast, nine species of parasites, 31% (89/285) positive, were obtained by AMS III, while 10 species, 22% (62/285) were found by SFL. Overall, 12 species of parasites were detected by the three methods: four species of nematoda (Trichuris trichiura, Ascaris lumbricoides, hookworm, and Enterobius vermicularis); five species of protozoa (Giardia intestinalis, Entamoeba histolytica-like cyst, E. coli, Cyclospora sp, Blastocystis hominis); two unidentified species of nematode eggs; and one unidentified species of mite egg.