Current prevalence and geographic distribution of helminth infections in the parasitic endemic areas of rural Northeastern Thailand.

BACKGROUND: Helminth infection is a global health issue that not only causes acute helminthiasis but long-term infection may lead to complicated symptoms as well as severe complications. The World Health Organization cooperated with the Ministry of Public Health in many countries, particularly where high prevalence, spending a lot of resources for limiting the infection. In Thailand, the incidence of parasitic helminth infections was continuously declined in the last few decades according to several campaigns for parasitic elimination. However, the rural community in the northeast of Thailand where the highest prevalence of the country still needs to be monitored. This present study aims to report the current prevalence of parasitic helminth infections in Nakhon Ratchasima and Chaiyaphum provinces where sharing a huge area of the northeastern region of Thailand but only a few studies have been published. METHODS: The stool specimens were collected from 11,196 volunteers and processed by modified Kato-Katz thick smear, PBS-ethyl acetate concentration techniques, and PCR. The epidemiological data were collected, analyzed, and used for generating of parasitic hotspots. RESULTS: The results indicated that O. viverrini remains the major parasite in this area with a total prevalence of 5.05% followed by Taenia spp., Hookworms, T. trichiura, and Echinostoma spp., respectively. Mueang district of Chaiyaphum province has the highest prevalence especially O. viverrini with a prevalence of 7.15% that higher than the latest national surveillance. Interestingly, the prevalence of O. viverrini was hugely reported (more than 10%) in five subdistricts. The geographic localization of O. viverrini infections revealed that a lot of water reservoirs such as the lakes or branches of the river in the two-most prevalent subdistricts. Our finding indicated that gender and age were insignificantly different. CONCLUSION: This finding suggested that the parasitic helminth infection in the rural areas of northeast of Thailand remains high and the housing location is a major contributing factor for the parasitic infection.

Morphology and Mitochondrial Genome of Fischoederius sp. 1 in Thailand.

A rumen fluke Fischoederius elongatus is assigned to the type species of genus Fischoederius, family Gastrothylacidae. However, the mitochondrial sequences recently published are thought to be of inconsistent species, suggesting that several morphologically similar but genetically distinct species might be classified as Fischoederius elongatus. Thus, mentions of F. elongatus from South, Southeast, and East Asia might unintentionally refer to different species. The present work describes morphology and a full mitochondrial genome sequence of one of these species. The fluke specimens were collected from 2 infected cattle in Thailand. An interesting finding was the presence of a second tRNA-Asp gene next to a partial ND1 gene. It is suggested that these duplicated sequences are the remnants of non-reciprocal recombination events caused by inverted repeats located between ND2 and ND1 mitochondrial genes.

Fischoederius elongatus (Poirier, 1883) Stiles & Goldberger, 1910, a cryptic species of pouched amphistome (Gastrothylacidae)?

Rumen flukes in the genus Fischoederius are neglected foodborne parasites of cattle in Asia. Fischoederius elongatus, first described in 1883 from a sample collected in Indonesia is the type-species of the genus and is found from South to East Asia. In this study Fischoederius spp were collected from cattle in Thailand. The flukes resembled F. elongatus and images of 48 specimens were taken and their DNA was isolated. The mtDNA sequence of the cytochrome c oxidase subunit I (COX1) gene was amplified by PCR and used for restriction analysis with MseI. Nine restriction patterns (A-I) were observed and the COX1 mtDNA sequence for each pattern was determined. Phylogenetic analysis clustered the nine COX1 sequences into five groups with 4.6-9.6 % sequence differences between the groups. This is beyond intragenic variation observed for the COX1 gene in other organisms and suggested that the analyzed specimens represented several species. A comparative transcriptome analysis of specimens with COX1 MseI patterns A, C, E supported this finding. The observed median base differences, both absolute and relative, in the protein coding sequences of 999 orthologs were similar to those between distinct fruit fly species. It is proposed that the genus Fischoederius contains undescribed species that follow the classic description of F. elongatus.