Prevalence and diversity of gastrointestinal parasites on pig farms in Kalasin Province, Thailand.

Background and Aim: Gastrointestinal (GI) parasite infections are the foremost and prevalent diseases that affect pigs in Thailand. This study aimed to determine the prevalence of GI parasites among pigs in Kalasin Province. This study is the first attempt to understand the occurrence of GI parasites in pigs within Kalasin province using fecal samples as the methodology. Materials and Methods: We collected 324 fecal samples directly from the rectums of pigs from May to July 2023. The formalin-ethyl acetate concentration and floatation methods were used to examine these samples. The eggs or oocysts were identified by observing their morphology and size under a light microscope. Results: Of the 324 fecal samples examined, 276 tested positive for gastrointestinal parasitic infections, resulting in a prevalence rate of 85.19%. Nematodes were the most prevalent, with Strongyle-type infections being the highest in 267 cases (82.41%), followed by Ascaris suum in 222 cases (68.52%), and Trichuris spp. in 152 cases (46.91%). Strongyloides spp. infections were also observed in 92 cases (28.40%). However, trematode infection was relatively rare, with only Fasciola spp. found in 15 cases (4.63%). We identified Eimeria spp. in 87 cases (26.85%), Iodamoeba spp. in 70 cases (21.60%), Balantidium coli in 67 cases (20.68%), and Isospora spp. in 52 cases (16.05%). Notably, most of the positive fecal samples showed double infections with a prevalence rate of approximately 38.27%. Single infections were the next most common, accounting for 25.31% of the cases, followed by 3 parasites (14.81%) and 4-5 parasites (6.79%). Conclusion: This study underscores the high endemicity of GI parasites among pigs in Kalasin province. To improve prevention and control measures, it is recommended to establish a health monitoring program that includes deworming and emphasizes good hygiene practices. The insights gained from this study will contribute to the enhancement of pig farming practices in Kalasin province, ultimately leading to improved production and profitability. In addition, future research should focus on detecting these parasites in Kalasin and exploring their relationship with human transmission cycle.

Prevalence of Ehrlichia-, Babesia-, and Hepatozoon-infected brown dog ticks in Khon Kaen Province, Northeast Thailand.

Background and Aim: The brown dog tick, Rhipicephalus sanguineus sensu lato, is the most common tick found on domestic dogs in Southeast Asia, including Thailand. Canine tick-borne pathogens are a public health concern worldwide. Tick-borne diseases are diagnosed by identifying pathogens based on the morphological or molecular analyses of dog blood samples. However, the collection of ticks, a non-invasive procedure, is easier than drawing blood. This study aimed to demonstrate the usefulness of collecting brown dog ticks for the diagnosis of tick-borne diseases and for estimating the prevalence of tick-borne pathogens among companion dogs in Khon Kaen, Northeast Thailand. Materials and Methods: Seventy brown dog ticks from 70 companion dogs in Khon Kaen Province, Thailand, were evaluated for molecular evidence of tick-borne pathogens, including Babesia spp., Ehrlichia canis, and Hepatozoon canis. Ticks were collected from dogs at a private animal hospital based on the presence of at least one of the three inclusion criteria: fever, anorexia, or lethargy. Molecular diagnosis was performed using conventional polymerase chain reaction for the detection of pathogens. Results: Of the 70 ticks collected from 70 sick dogs, 55 (78.57%) were positive for tick-borne pathogens. The most common infection was a single infection with H. canis (65.71%) followed by Babesia spp. (31.43%) and E. canis (30.00%). Coinfection was observed in 14 ticks (20.00%), and coinfection with Babesia spp. and E. canis was the most prevalent double infection (n = 6). The prevalence of coinfection was identical for H. canis mixed with Babesia spp. and H. canis mixed with E. canis (n = 4). Conclusion: The present study showed that tick-borne pathogens are highly prevalent among companion dogs in Khon Kaen Province. Therefore, we encourage an increase in tick control or the reduction and prevention of tick-borne diseases in this region. Furthermore, this study revealed that ticks are valuable samples for the molecular detection of tick-borne pathogens.

Prevalence of gastrointestinal parasites in cattle in Kalasin Province, Thailand.

BACKGROUND AND AIM: Parasitic infections are one of the major problems to the production of cattle in Thailand. The study was conducted to determine the prevalence of gastrointestinal (GI) parasites of cattle in Kalasin Province, Thailand. MATERIALS AND METHODS: A total of 333 fecal samples of cattle were collected directly from the rectum. The fecal samples were subjected to formalin-ethyl acetate concentration methods for examination. The eggs or oocysts were identified based on the morphology and size of the eggs or oocysts. RESULTS: Out of 333 fecal samples examined, 320 were found positive for GI parasitic infections with a prevalence of 96.09%. Overall, among the prevalence of nematodes, trematodes, and protozoa, the most prevalent parasites were Strongyle-type 278 (84.24%), followed by Strongyloides spp. 54 (16.36%) and Trichuris spp. 75 (22.73%), while Protozoan oocyst recorded Eimeria spp. amounted to 131 (39.7%). Fasciola spp. and Paramphistomum spp. were 67 (20.30%) and 81 (24.55%), respectively. Most of the positive fecal samples were infected with the double infection which has the highest prevalence rate of about 40.24%, followed by single, three, and 4-5 types of parasites 30.63, 16.82, and 7.21%, respectively. CONCLUSION: This study suggests that Kalasin Province is highly endemic for GI parasites and this area may be an important source for an outbreak. Therefore, every household should deworm its cattle and eliminate and control snails as intermediate hosts. Findings from this study provide information that will assist in improving the cattle in Kalasin Province for better production and higher profitability.

Comparison of polymerase chain reaction and microscopy for the detection of Fasciola spp. in the fecal matter of domestic bovines in Kalasin Province, Thailand.

BACKGROUND AND AIM: Fasciola spp. are important foodborne trematodes and waterborne zoonotic parasites that cause health problems and economic losses worldwide, including in Thailand. Fasciola spp. are usually detected by sedimentation or the formalin-ethyl acetate concentration technique (FECT) under microscopy, which is less specific and sensitive. Accurate detection is important to detect real incidence for protection against and elimination of fasciolosis in the area. This study aimed to determine the distribution of Fasciola spp. and compare the specificity and sensitivity of FECT under microscopy to that of polymerase chain reaction (PCR) in cattle feces. MATERIALS AND METHODS: The study was conducted in Kalasin Province, Thailand. Feces of 46 cattle were investigated for infection with Fasciola spp. To detect infection, FECT under microscopy and PCR amplification of the 28S rRNA gene of Fasciola spp. were used to identify egg parasites. RESULTS: Feces of 16 of 46 (34.78%) cattle were positive for Fasciola spp. using FECT under microscopy, whereas PCR showed that 67.39% (31 of 46) were positive for Fasciola spp. False-negative results were as high as 32.61% when diagnosed under microscopy. CONCLUSION: This study confirmed the infection of cattle with Fasciola spp. in Kalasin Province, indicating that PCR demonstrated higher sensitivity and specificity when diagnosing infection. FECT under microscopy can still be used as a primary and traditional method for diagnosis. However, relapse cases of Fasciola spp. and Paramphistomum spp. should be diagnosed by microscopy combined with PCR. This is the first report on the molecular distribution of fecal samples in cattle in Kalasin Province.

Suppression of aquaporin, a mediator of water channel control in the carcinogenic liver fluke, Opisthorchis viverrini.

BACKGROUND: Opisthorchiasis and Opisthorchis viverrini-associated bile duct cancer represent major public health threats in Thailand and Laos. The tegument of this food borne fluke plays pivotal roles in parasite metabolism, homeostasis and osmoregulation. Excretory/secretory products also pass from the fluke to the biliary environment, products that likely underlie pathogenesis of liver fluke infection. Aquaporins (AQPs), belong to the major intrinsic protein superfamily of integral plasma membrane channel proteins that selectively transport water across cell membranes. AQPs play key roles as water and ion transport channels through the tegument of helminth parasites. METHODS: Here, two forms of AQP mRNAs from the adult developmental stage of O. viverrini, termed O. viverrini aquaporin-1 and -2 (Ov-aqp-1 and -2) were investigated. Roles of Ov-aqp-1 and -2 in the movement of water across the tegument of this carcinogenic liver fluke were investigated using RNA interference. RESULTS: Ov-AQP-1 and Ov-AQP-2 contain unique characteristic asparagine-proline-alanine (NPA) motifs of AQP transmembrane proteins. Phylogenetic analysis indicated that Ov-AQPs belong to an expanding group of aquaglyceroporin-like water channel proteins characterized from helminth and protozoan parasites, which is pivotal to the specialized requirements of water and solute control during parasitism. Elevated transcription of Ov-aqp-1 was evident in the egg, cercaria, metacercaria and adult stages of O. viverrini, whereas Ov-aqp-2 transcripts were detected at higher level in egg, metacercaria, cercaria and adult stage, respectively. RNA interference using electroporated dsRNA suppressed transcript levels of Ov-aqp-1 and Ov-aqp-2 in adult worms by 58-99% over periods of up to 16 days in vitro. Suppression of Ov-aqp-1 and Ov-aqp-2 in vitro disabled water transport in adult flukes. CONCLUSION: The apparently pivotal roles of Ov-AQP in solute homeostasis at the fluke surface suggest that deeper investigation will be informative for the pathophysiology of O. viverrini, and may uncover intervention targets, particularly in view of the singularly notable predilection of this pathogen for residence within ducts of the biliary tree.

Molecular characterization of a tetraspanin from the human liver fluke, Opisthorchis viverrini.

BACKGROUND: The human liver fluke, Opisthorchis viverrini, is designated as a group 1 carcinogen, and is the major risk factor for cholangiocarcinoma in endemic countries throughout Southeast Asia. Proteins in the excretory-secretory products and tegumental surface membranes of the fluke have been proposed to play pivotal roles in parasite survival in the host, and subsequent pathogenesis. These macromolecules are therefore valid targets for the development of vaccines and new drugs to control the infection. Tetraspanins (TSP) are prominent components of the tegument of blood flukes where they are essential for tegument formation, are directly exposed to the immune system, and are major targets for a schistosomiasis vaccine. We propose that similar molecules in the surface membranes of O. viverrini are integral to tegument biogenesis and will be efficacious vaccine antigens. METHODOLOGY/PRINCIPAL FINDINGS: The cDNA sequence encoding O. viverrini tetraspanin-1 (Ov-TSP-1) was identified and cloned. The Ov-tsp-1gene was isolated from a cDNA library. Ov-tsp-1 mRNA was expressed most highly in metacercariae and eggs, and to a lesser extent in juvenile and adult worms. Immunolocalization with adult flukes confirmed that Ov-TSP-1 was expressed in the tegument and eggs in utero. Western blot analysis of rOv-TSP-1 probed with sera from O. viverrini-infected humans and hamsters indicated that both hosts raise antibody responses against the native TSP. Using RNA interference we silenced the expression level of Ov-tsp-1 mRNA in adult flukes by up to 72% by 10 days after delivery of dsRNA. Ultrastructural morphology of adult worms treated with Ov-tsp-1 dsRNA displayed a distinctly vacuolated and thinner tegument compared with controls. CONCLUSIONS/SIGNIFICANCE: This is the first report of a tetraspanin from the tegument of a liver fluke. Our data imply that tetraspanins play important structural roles in the development of the tegument in the adult fluke. Potential uses of O. viverrini tetraspanins as novel interventions are discussed.