Asymptomatic Human Paragonimiasis among the Karen People in Tak Province, Thailand: A Case Report

During the mobile clinic activities in Tak Province, Thailand, Paragonimus sp. eggs were found in a fecal sample of a 72-year-old Karen resident. Paragonimus DNA was amplified from the stool sample and identified to P. heterotremus. The patient did not have any symptoms. Apparent pulmonary lesion was not found on the chest X-ray. The patient admitted habitual consumption of semi-cooked or roasted waterfall crabs for several years. The waterfall crabs collected from stream near the village were found negative for Paragonimus metacercariae. In northern Thailand, paragonimiasis remains as one of the public health concerns and should be ruled out for asymptomatic pulmonary patients.

Subtype Distribution of Blastocystis in Thai-Myanmar Border, Thailand

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.

House Flies: Potential Transmitters of Soil-Transmitted-Helminth Infections in an Unsanitary Community

This study aimed to determine an appropriate technique for isolating helminthic objects from the exteriors of the bodies of lies, and to investigate helminth transmission rates among lies in an unsanitary community. The study area was Ban Nam Khem Village, Takua Pa District, Phang-nga Province, Thailand. In 2006, the prevalence of soil-transmitted-helminth (STH) infections in the community was 34.9%. Soil contamination in the swamp areas, where human feces were observed, ranged between 41.2-100% in the period February 2005-May 2006. Flies were abundant in defecation areas and around houses. One year after treatment and health education, the prevalence decreased to 22.5%. While the infection rate among the schoolchildren decreased, the rate among the villagers increased to 50.0%. In June 2007, the soil contamination rate was 13.3%. The 567 houselies in the study were all Chrysomya megacephala. Hookworm and Trichuris trichiura eggs on the body surfaces of the lies were isolated using an ultrasonic cleaner. The helminth transmission rate for lies in the defecation area was 25.9%, and in the household surroundings 11.8%. The average number of eggs on the body surfaces of lies in the defecation area was 0.4. After feeding on human excreta, 508 resting lies left 0.5 g of feces with pathogens in the surroundings. Anthelminthic treatment and health education were repeated to improve the helminth infection situation in the community. Manual shaking and ultrasonic-cleaner techniques provided equal detection rates (80%), but ultrasonic cleaning retrieved more eggs.

Trichinellosis in Thailand: Epidemiology,Prevention and Control

Trichinellosis (trichinosis), a helminthic zoonotic disease caused by parasitic nematodes of thegenus Trichinella, can be transmitted from animals to humans. The disease is distributedworld-wide and has been the source of major public-health problems in many countries, includingArgentina, Mexico, China, Japan, Korea, Thailand, and some European countries. Human infectionoccurs by ingesting the raw, or inadequately cooked, meat of animals harboring infective larvae. Themain sources of human infection are pork and pork products, game meat, and horse meat. Since1962, trichinellosis outbreaks have occurred almost every year in Thailand, with more than 6,000infected cases. The causative agents of the Thai outbreaks have mostly been encapsulated T. spiralislarvae. However, in 1994, there was an outbreak due to T. pseudospiralis in Chumphon Province,southern Thailand. This was the first report of an outbreak in Thailand due to infection with nonencapsulatedTrichinella larvae. Subsequently, in 2006 and 2007, two outbreaks due to T. papuae, alsoknown to have non-encapsulated larvae, were reported in Uthai Thani Province. Health education forvillagers in rural communities is important, to prevent and control trichinellosis and other parasiticinfections.

Egg Laying Capacity of Haplorchis taichui (Digenea: Heterophyidae) in Humans

Quantitative fecal egg counts represented as the number of eggs per gram of feces (EPG) are generally a reliable parameter to estimate the worm burden of intestinal and hepatic parasitoses. Although Haplorchis taichui (Digenea: Heterophyidae) is one of the most common minute human intestinal flukes, little is known about the relationship between EPG and the actual worm burden in patients or the severity of the disease. In the present study, fecal samples were collected from 25 villagers in northern Thailand before and after praziquantel treatment. The EPG values of each participant were determined by the modified cellophane thick smear method, and adult worms were collected from the whole stool after the treatment. Eggs per day per worm (EPDPW) of H. taichui were estimated 82 from egg counts and expelled worms. The EPG was not well correlated with the worm burden, and a reverse correlation was observed between the EPDPW and the worm burden.

Anchitrema sanguineum (Digenea: Anchitrematidae) Accidentally Found during Colonoscopy of a Patient with Chronic Abdominal Pain: A Case Report

In November 2007, a 46-year-old male Thai patient presented with chronic abdominal pain for over 3 years. Colonoscopy revealed a small parasite of about 2 x 1 mm in size attached to the cecum mucosa. The worm was removed endoscopically, fixed, and stained for morphological observations. The specimen was identified as Anchitrema sanguineum (Digenea: Anchitrematidae), a trematode first reported in a reptile, Chamaeleo vulgaris, from Egypt, and then sporadically found in the intestines of insectivorous bats and other mammals. The patient was treated with praziquantel but no more worms were found in his stool. His symptoms improved slightly but not cured completely. It remains unclear whether the chronic abdominal pain of the patient was caused by this trematode infection. Whatever is the pathogenicity of this trematode, this is the first human case of A. sanguineum infection in the literature.