Orthocoelium streptocoelium is a common paramphistome species parasitizing the rumen and/or reticulum of small ruminants, leading to significant losses. This study first determined the complete mitochondrial (mt) genome of O. streptocoelium. The complete mt genome of O. streptocoelium was amplified, sequenced, assembled, analysed and then compared with those of other digeneans. The entire mt genome of O. streptocoelium is 13,800 bp in length, which is smaller than those of other digeneans except for Opisthorchis viverrini. This mt genome contains 12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and two non-coding regions. The arrangement of the O. streptocoelium mt genome is the same as those of other digeneans except for Schistosoma haematobium and Schistosoma spindale. Phylogenetic analyses based on concatenated amino acid sequences of the 12 protein-coding genes representing 16 digeneans were conducted to assess the relationship of O. streptocoelium with other digeneans. The result indicated that O. streptocoelium is closely related to Paramphistomum cervi and Fischoederius elongates, which is in accordance with their relationships by taxonomy. This complete mt genome of O. streptocoelium enriched the mitochondrial genome data of paramphistomes and provided important molecular markers for diagnostics and studies of population variation, epidemiology, ecology and evolution of O. streptocoelium and other digeneans.

A unique adaptation of many internal parasites of mammals is their ability to stay in the intestine for extended periods of time and resist the normal peristaltic movements and forces that push and expel material. To better understand parasite adhesion behaviour and replicate their attachment method in medical devices, an experiment was designed and performed using the rat tapeworm, Hymenolepis diminuta. The experiment employed a tensile test machine and a digital scale and was designed to calculate the attachment strength of the scolex to the mucosa through the change of the value of the digital scale during the tensile test. The attachment force of H. diminuta is 0.021 ± 0.011 g. This method could be applied in studies of parasite biomechanics and the results may help medical device researchers to better mimic the unique functional morphology of this species of parasite.

A new species of Skrjabinolecithum (Digenea: Waretrematinae), Skrjabinolecithum pyriforme n. sp., has been found in the intestines of Liza haematocheila and Mugil cephalus from the Primorsky Region, Russia. These worms differ from S. vitellosum and S. lobolecithum by the presence of two caeca, as do S. spasskii, S. indicum and S. bengalensis. These species differ morphologically from S. pyriforme n. sp. by a number of features, including body width, oral sucker, pharynx, eggs and ratio of length and width of the body. The most similar species to S. pyriforme n. sp. is Platydidymus flecterotestis (Zhukov, 1971) with some differences in maximal body length, testis and egg sizes. The results of molecular analysis confirmed that this new species belongs to Skrjabinolecithum on the basis of close relationships with S. spasskii-type species.

Human gnathostomiasis is a food-borne zoonosis caused by a tissue nematode of the genus Gnathostoma. The disease is highly endemic in Asia, including Thailand. The freshwater swamp eel (Monopterus albus), the second intermediate host of the gnathostome nematode, has an important role in transmitting the infection in Thailand. Surveys on the infective larvae of Gnathostoma spinigerum based on morphological features in freshwater swamp eels have been performed continuously and reported in Thailand. However, there is still limited molecular data on intra-species variations of the parasite. In this study, a total of 19 third-stage larvae of morphologically identified G. spinigerum were collected from 437 liver samples of freshwater swamp eels purchased from a large wholesale market in Bangkok, Thailand. Molecular characterization based on mitochondrial cytochrome c oxidase subunit I (COI) sequences was performed to elucidate their genetic variations and phylogenetic relationship. Among the 19 infective larvae recovered from these eels, 16 were sequenced successfully. Phylogenetic analyses inferred from the partial COI gene showed the presence of three distinct COI haplotypes. Our findings confirm the presence of G. spinigerum as the main species in Thailand.

Canine echinococcosis is caused by the adult tapeworm of Echinococcus granulosus. As intermediate hosts, humans and livestock become infected following ingestion of eggs that are passed in the faeces of dogs. Mature eggs develop into hydatid cysts in different organs, leading to hydatid disease, which is a serious public health problem. In the present study, we investigated the proportion of mature eggs of E. granulosus in 140 dogs from three regions of Tunisia. The results showed the predominance of immature E. granulosus eggs in infected dogs and the occurrence of a small proportion of oncospheres. The ability of immature eggs to infect humans and livestock is discussed.

The United States of America (USA) has the largest international population of any nation in the world. Immigrants from Latin American countries, where intestinal parasites are endemic, comprise more than half of this population. This study aims to determine the prevalence of strongyloidiasis, a potentially deadly parasitic infection, in foreign-born individuals. We conducted a cross-sectional study in Washington, DC, to determine the seroprevalence of Strongyloides stercoralis infection using an NIE-ELISA IgG antibody assay. Multi-parallel quantitative real-time polymerase chain reaction (qPCR) was performed in stool samples of NIE-ELISA-positive patients to investigate possible polyparasitism. The NIE-ELISA assay detected an S. stercoralis prevalence of 4.2% in a group of 119 volunteers. Combining NIE-ELISA and qPCR detected a parasite prevalence of 5.0%. Our results underscore the relevance of systematic testing for gastrointestinal parasites in individuals from endemic regions. It also makes a case for a survey in the USA to identify immigrants' risk for strongyloidiasis and other gastrointestinal parasitic infections.

Kalicephalus is a genus of strongylid nematodes infecting snakes and causing serious diseases and even death when it is complicated with secondary bacterial infections. The infection of snakes with Kalicephalus has been reported in many countries in the world. However, little information is available on the prevalence of Kalicephalus in snakes in China. In the present study, the prevalence of Kalicephalus in snakes was investigated. The worms were examined, counted and identified to species according to existing keys and descriptions. Three species of Kalicephalus, namely K. indicus, K. bungari and K. brachycephalus, were found in six species of snakes (Elaphe carinata, Zaocys dhumnade, Naja najaatra, Elaphe taeniura, Bungarus multicinctus and Dinodon rufozonatum). The total prevalence of Kalicephalus in snakes in Hunan Province was 39.7%. The most common species was K. indicus, with the highest prevalence 72.8%, followed by K. bungari (24.0%). The prevalence of K. brachycephalus was 0.9%. This is the first report on the prevalence of Kalicephalus species in snakes in China, and the findings have important implications for the control of Kalicephalus infections in snakes in China.

Setaria digitata is a filarial parasite that causes fatal cerebrospinal nematodiasis in goats, horses and sheep, resulting in substantial economic losses to livestock farmers. In the present study, the complete mitochondrial (mt) genome of S. digitata from China was determined, characterized and compared with that of S. digitata from Sri Lanka. The identity of the mt genomes was 98.3% between S. digitata from China and Sri Lanka, and the complete mt genome sequence of S. digitata from China was slightly shorter (25 bp) than that from Sri Lanka. For the 12 protein genes, this comparison revealed sequence differences at both the nucleotide (1.4%) and amino acid (2.2%) levels. The present study determined the complete mt genome sequence of S. digitata from China, providing novel genetic markers for the study of the population genetics and molecular epidemiology of S. digitata in animals.

Consuming raw and undercooked meat is known to enhance the risk of human toxocariasis because Toxocara species have a wide range of paratenic hosts, including chickens. The aim of this study was to identify species of Toxocara in naturally infected broiler chickens using molecular approaches. A polymerase chain reaction (PCR) method was used for the differentiation of Toxocara canis and Toxocara cati larvae recovered from tissues and organs, and identified by microscopic observations. Thirty-three 35- to 47-day-old broiler chickens were used for examination of Toxocara larvae. The duodenum, liver, lungs, heart, kidneys, skeletal muscles and brain of each chicken were examined using the pepsin method, and DNA from each tissue was extracted as the template for PCR assay. The findings revealed that 5 of 33 (15.2%) broiler chickens were infected with Toxocara larvae. Larvae were recovered from the liver (n = 19), duodenum (n = 8), skeletal muscles (n = 8) and brain (n = 2) of broiler chickens naturally infected with Toxocara spp. The results showed that the frequencies of the species in the chickens were T. canis larvae (n = 5, 83.3%) and T. cati larvae (n = 1, 16.7%). Our data from the present study demonstrated the importance of broiler chickens as a paratenic host for the parasite's life cycle in the environment. The implementation of DNA amplification as a routine diagnostic technique is a specific and alternative method for identification of Toxocara larvae, and allowed the observation of specific species under field conditions within the locations where broiler chickens are typically raised and exposed to Toxocara spp. eggs or larvae.

Paramphistomosis, caused by paramphistomid flukes, is a gastrointestinal parasitic disease of domestic and wild ruminants. Originally thought to be limited to the tropics and subtropics, the disease has recently been reported in temperate regions. Here we describe the concurrent infection of a red deer doe (Cervus elaphus) with Paramphistomum leydeni and Paramphistomum cervi. This is the first report of P. leydeni in Croatia. Flukes were identified on the basis of morphological keys (tegumental papillae) and sequencing of the internal transcribed spacer region 2 in ribosomal DNA. Our results confirm that the absence of tegumental papillae allows P. cervi to be differentiated morphologically from other paramphistomid species in Europe based on incident light stereomicroscopy. Nevertheless the limitations of morphological identification and taxonomic issues suggest that previous findings on paramphistomid infection should be interpreted carefully. The possible worldwide distribution of these pathogens means that paramphistomosis may be more common and its economic impact greater than previously thought.

Sparganosis is one of the top three tissue-dwelling heterologous helminthic diseases, along with cysticercosis and paragonimiasis, in Korea. Due to a lack of effective early diagnosis and treatment methods, this parasitic disease is regarded as a public health threat. This study evaluated reactivity, against sparganum extracts, of sera from inhabitants of Cheorwon-gun, Goseong-gun and Ongjin-gun in Korea. The sera from 836 subjects were subjected to enzyme-linked immunosorbent assay and immunoblot analysis. The sera from 18 (5.8%) and 15 (5.1%) inhabitants in Cheorwon-gun (n = 312) and Goseong-gun (n = 294), respectively, exhibited highly positive reactions to the sparganum antigen, whereas only two (0.9%) inhabitants in Ongjin-gun (n = 230) showed positivity. We sought antigenic proteins for serodiagnosis of positive sera by immunoproteomic approaches. Total sparganum lysates were separated by two-dimensional electrophoresis and then subjected to immunoblot analysis with mixed sparganosis-positive sera. We found seven antigenic spots and identified paramyosin as an antigenic protein by liquid chromatography–mass spectrometry. By two-dimensional (2D)-based mass analysis and immunoblotting against sparganosis-positive sera, paramyosin was identified as a candidate antigen for serodiagnosis of sparganosis.