The majority of Giardia infections are transmitted by the fecal-oral route and cause giardiasis. Children who live in crowded conditions or low socio-economic areas are the risk group for Giardia infection. Interestingly, most of them are asymptomatic or only mildly infected and can shed the Giardia cysts in the environment. Thus, the diagnosis of Giardia infection in asymptomatic or mild infection plays an important role in achieving control of Giardia duodenalis transmission. The objective of this study was to examine parasitic infections using microscopy and to develop a real-time PCR method for detection of Giardia infection in the stool samples of children living on the Thai-Myanmar border. Both species-specific primers and fluorescent labeled G. duodenalis probe were designed using small-subunit ribosomal RNA (ssrRNA). The results showed that 10 (7.69%) and 40 (30.77%) of 130 stool samples were positive for G. duodenalis by microscopy and real-time PCR respectively. Only 3 out of 9 liquid stools revealed G. duodenalis positive using microscopy, but all of them were G. duodenalis-positive using real-time PCR. The detection limit of real-time PCR for G. duodenalis was 0.1 pg/25 µl reaction. It can detect both mild and asymptomatic Giardia infections in children living on the Thai-Myanmar border.

Blastocystis is a common zoonotic enteric protozoan that has been classified into 17 distinct subtypes (STs). A cross-sectional study was conducted to determine the prevalence and subtype distributions of Blastocystis in villagers living along the Chao Phraya River, Ayutthaya Province, Thailand, and to assess the risk of zoonotic infection. In total, 220 stool samples were collected, and DNA was extracted. PCR and sequencing were performed with primers targeting the small-subunit ribosomal RNA (SSU rRNA) genes. Blastocystis was present in 5.9% (13/220) of samples, and ST3 (5.0%; 11/220) was the predominant subtype, followed by ST2 (0.45%; 1/220) and ST6 (0.45%; 1/220). Phylogenetic trees were constructed with the maximum-likelihood method based on the Hasegawa–Kishino–Yano + G + I model, neighbor-joining, and maximum parsimony methods. The percentage of bootstrapped trees in which the associated taxa clustered together was relatively high. All the sequences of the Blastocystis-positive samples (KU051524–KU051536) were closely related to those from animals (pig, cattle, and chicken), indicating a zoonotic risk. Therefore, the villagers require proper health education, especially regarding the prevention of parasitic infection, to improve their personal hygiene and community health. Further studies are required to investigate the Blastocystis STs in the animals living in these villages.
Animals ; Blastocystis* ; Cattle ; Cross-Sectional Studies ; DNA ; Health Education ; Humans ; Hygiene ; Methods ; Polymerase Chain Reaction ; Prevalence ; Rivers* ; RNA, Ribosomal ; Thailand* ; Trees ; Zoonoses

Blastocystis sp. is a common zoonotic intestinal protozoa which has been classified into 17 subtypes (STs). A cross-sectional study was conducted to determine the prevalence and subtype distribution of Blastocystis in villagers living on the Thai-Myanmar border, where the risk of parasitic infection is high. A total of 207 stool samples were collected and DNA was extracted. PCR and sequencing using primers targeting small-subunit ribosomal RNA (SSU rRNA) gene were performed. The prevalence of Blastocystis infection was 37.2% (77/207). ST3 (19.8%; 41/207) was the predominant subtype, followed by ST1 (11.6%; 24/207), ST2 (5.3%; 11/207), and ST4 (0.5%; 1/207). A phylogenetic tree was reconstructed using the maximum likelihood (ML) method based on the Hasegawa-Kishino-Yano + G + I model. The percentage of bootstrapped trees in which the associated taxa clustered together was relatively high. Some sequences of Blastocystis positive samples (TK18, 39, 46, 71, and 90) were closely related to animals (pig and cattle) indicating zoonotic risks. Therefore, proper health education in parasitic prevention for the villagers should be promoted to improve their personal hygiene. Further longitudinal studies are required to monitor the prevalence of parasitic infections after providing health education and to investigate Blastocystis ST in animals living in these villages.
Adult ; Aged ; Animals ; Blastocystis/*classification/immunology/*isolation & purification ; Blastocystis Infections/*parasitology ; Cluster Analysis ; Cross-Sectional Studies ; DNA, Protozoan/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Female ; Humans ; Male ; Middle Aged ; Myanmar ; Phylogeny ; RNA, Ribosomal, 18S/genetics ; Rural Population ; Sequence Analysis, DNA ; Seroepidemiologic Studies ; *Serogroup ; Thailand ; Young Adult

Objective To determine the ability of oysters to trap and maintain viable Cryptosporidium oocysts, and the feasibility of Cryptosporidium multiplication in oysters' organs. Methods Seventy oysters were raised in experimentally seeded natural seawater for up to 3 months, with weekly oocysts inoculations. Cryptosporidium oocysts, viable and non-viable, as well as other stages were detected using two immunofluorescence vital staining techniques (Sporo-Glo and Merifluor