Far-East Asian Toxoplasma isolates share ancestry with North and South/Central American recombinant lineages

Toxoplasma gondii is a global protozoan pathogen. Clonal lineages predominate in Europe, North America, Africa, and China, whereas highly recombinant parasites are endemic in South/Central America. Far East Asian T. gondii isolates are not included in current global population genetic structure analyses at WGS resolution. Here we report a genome-wide population study that compared eight Japanese and two Chinese isolates against representative worldwide T. gondii genomes using POPSICLE, a novel population structure analyzing software. Also included were 7 genomes resurrected from non-viable isolates by target enrichment sequencing. Visualization of the genome structure by POPSICLE shows a mixture of Chinese haplogroup (HG) 13 haploblocks introgressed within the genomes of Japanese HG2 and North American HG12. Furthermore, two ancestral lineages were identified in the Japanese strains; one lineage shares a common ancestor with HG11 found in both Japanese strains and North American HG12. The other ancestral lineage, found in T. gondii isolates from a small island in Japan, is admixed with genetically diversified South/Central American strains. Taken together, this study suggests multiple ancestral links between Far East Asian and American T. gondii strains and provides insight into the transmission history of this cosmopolitan organism.

Expression profile analysis of the transient receptor potential (TRPM) channel, a possible target of praziquantel in Schistosoma japonicum

The WHO considers schistosomiasis, which is controlled by the mass administration of the drug praziquantel (PZQ), to be a neglected tropical disease. Despite its clinical use for over four decades, PZQ remains the only choice of chemotherapy against this disease. Regarding the previous studies that demonstrated that PZQ activates the transient receptor potential (TRP) channel in Schistosoma mansoni (Sm.TRPMPZQ), the expression profile of the ortholog of this channel gene (Smp_246790.5) in S. japonicum (EWB00_008853) (Sj.TRPMPZQ) was analyzed. The relative expression of this gene in various stages of the parasite lifecycle was analyzed by quantitative real-time reverse transcription-PCR (qRT-PCR), and the expression of Sj.TRPMPZQ was observed by immunohistochemical staining using anti-serum against the recombinant Sj.TRPMPZQ protein. qRT-PCR revealed the significantly lower mRNA expression in the snail stage in comparison to other stages (p < 0.01). The relative quantity of the Sj.TRPMPZQ expression for paired females, unpaired males, and eggs was 60%, 56%, and 68%, respectively, in comparison to paired males that showed the highest expression (p < 0.05). Interestingly, immunostaining demonstrated that Sj.TRPMPZQ is expressed in the parenchyma which contains muscle cells, neuronal cells and tegument cells in adult worms. This may support the two major effects of PZQ-worm paralysis and tegument disruption-induced by channel activation. Moreover, the channel was expressed in both the eggshell and the miracidia inside, but could not be observed in sporocyst. These results suggest that the expression of Sj.TRPMPQZ corresponds to the known sensitivity of S. japonicum to PZQ.

Mitogenomic exploration supports the historical hypothesis of anthropogenic diffusion of a zoonotic parasite Echinococcus multilocularis

Animal movement across regions owing to human activity can lead to the introduction of pathogens, resulting in disease epidemics with medical and socioeconomic significance. Here, we validated the hypothesis that human activity, such as the transportation of infected animals, has played a significant role in introducing the zoonotic parasite Echinococcus multilocularis into Hokkaido, Japan, by synthesizing and evaluating parasite genetic data in light of historical records. Our analysis indicates that a major genetic group in Hokkaido originated from St. Lawrence Island, USA, which is in accordance with the route suggested by historical descriptions. Moreover, we identified a minor genetic group closely related to parasites found in Sichuan, China. This fact implies that parasite invasion in Japan may result from complex and inadvertent animal translocations. These findings emphasize the anthropogenic impacts on zoonotic parasite spread and provide a crucial perspective for preventing future potential epidemics.

Investigation of vertical and horizontal transmission of Spiroplasma in ticks under laboratory conditions

Many arthropods harbour bacterial symbionts, which are maintained by vertical and/or horizontal transmission. Spiroplasma is one of the most well-known symbionts of ticks and other arthropods. It is still unclear how Spiroplasma infections have spread in tick populations despite its high prevalence in some tick species. In this study, Ixodes ovatus, which has been reported to harbour Spiroplasma ixodetis at high frequencies, was examined for its vertical transmission potential under experimental conditions. Next, two isolates of tick-derived Spiroplasma, S. ixodetis and Spiroplasma mirum, were experimentally inoculated into Spiroplasma-free Haemaphysalis longicornis colonies and the presence of Spiroplasma in their eggs and larvae was tested. Our experimental data confirmed that S. ixodetis was transmitted to eggs and larvae in a vertical manner in the original host I. ovatus. In the second experiment, there was no significant difference in engorged weight, egg weight, and hatching rate between Spiroplasma-inoculated and control H. longicornis groups. This suggested that Spiroplasma infection does not affect tick reproduction. Spiroplasma DNA was only detected in the eggs and larvae derived from some individuals of S. ixodetis-inoculated groups. This has demonstrated the potential of horizontal transmission between different tick species. These findings may help understand the transmission dynamics of Spiroplasma in nature and its adaptation mechanism to host arthropod species.

Seasonal Variation and Factors Affecting Trypanosoma theileri Infection in Wild Sika Deer (Ezo Sika Deer Cervus nippon yesoensis) in Eastern Hokkaido

Trypanosoma (Megatrypanum) spp. are isolated from domestic and wild ruminants, including deer, worldwide. The prevalence of trypanosomes in mammals is influenced by a number of factors such as host age and vector abundance. However, the seasonal variation of and factors affecting trypanosome infection in the wild deer population remain elusive. In this study, we analyzed the seasonal variation in trypanosome prevalence and the factors that affect Trypanosoma theileri Laveran, 1902, infection in wild sika deer (Ezo sika deer) Cervus nippon yesoensis (Heude, 1884) in Eastern Hokkaido through a two-year survey. Seasonal variation in the prevalence of trypanosome infection in the deer population ranged from 0 to 41% as per hematocrit concentration and 17 to 89% as per PCR results. In general, the prevalence of T. theileri by PCR in 2020 was higher than that in 2019. Moreover, the prevalence was significantly higher in the aged population than among the younger population. These findings may explain why individual conditions and sampling season were associated with trypanosome prevalence. This is the first study to investigate the seasonal variation in and risk factors affecting trypanosome infection in wild deer.

Cloning, Expression and Evaluation of Thioredoxin Peroxidase-1 Antigen for the Serological Diagnosis of Schistosoma mekongi Human Infection

Schistosoma mekongi, a blood fluke that causes Asian zoonotic schistosomiasis, is distributed in communities along the Mekong River in Cambodia and Lao People's Democratic Republic. Decades of employing numerous control measures including mass drug administration using praziquantel have resulted in a decline in the prevalence of schistosomiasis mekongi. This, however, led to a decrease in sensitivity of Kato-Katz stool microscopy considered as the gold standard in diagnosis. In order to develop a serological assay with high sensitivity and specificity which can replace Kato-Katz, recombinant S. mekongi thioredoxin peroxidase-1 protein (rSmekTPx-1) was expressed and produced. Diagnostic performance of the rSmekTPx-1 antigen through ELISA for detecting human schistosomiasis was compared with that of recombinant protein of S. japonicum TPx-1 (rSjTPx-1) using serum samples collected from endemic foci in Cambodia. The sensitivity and specificity of rSmekTPx-1 in ELISA were 89.3% and 93.3%, respectively, while those of rSjTPx-1 were 71.4% and 66.7%, respectively. In addition, a higher Kappa value of 0.82 calculated between rSmekTPx-1 antigen ELISA and Kato-Katz confirmed better agreement than between rSjTPx-1 antigen ELISA and Kato-Katz (Kappa value 0.38). These results suggest that ELISA with rSmekTPx-1 antigen can be a potential diagnostic method for detecting active human S. mekongi infection.

Comparative mitogenomics elucidates the population genetic structure of Amblyomma testudinarium in Japan and a closely related Amblyomma species in Myanmar

Ticks are the second most important vector capable of transmitting diseases affecting the health of both humans and animals. Amblyomma testudinarium Koch 1844 (Acari: Ixodidae), is a hard tick species having a wide geographic distribution in Asia. In this study, we analyzed the composition of A. testudinarium whole mitogenomes from various geographical regions in Japan and investigated the population structure, demographic patterns, and phylogeographic relationship with other ixodid species. In addition, we characterized a potentially novel tick species closely related to A. testudinarium from Myanmar. Phylogeographic inference and evolutionary dynamics based on the 15 mitochondrial coding genes supported that A. testudinarium population in Japan is resolved into a star‐like haplogroup and suggested a distinct population structure of A. testudinarium from Amami island in Kyushu region. Correlation analysis using Mantel test statistics showed that no significant correlation was observed between the genetic and geographic distances calculated between the A. testudinarium population from different localities in Japan. Finally, demographic analyses, including mismatch analysis and Tajima’s D test, suggested a possibility of recent population expansion occurred within Japanese haplogroup after a bottleneck event. Although A. testudinarium has been considered widespread and common in East and Southeast Asia, the current study suggested that potentially several cryptic Amblyomma spp. closely related to A. testudinarium are present in Asia.

Genotyping of Theileria parva populations in vaccinated and non-vaccinated cattle in Malawi

Theileria parva is an apicomplexan protozoan parasite that causes bovine theileriosis (East Coast Fever; ECF) in central, eastern and southern Africa. In Malawi, ECF is endemic in the northern and central regions where it has negatively affected the development of dairy industry. Despite its endemic status the genetic population structure of T. parva in Malawi is currently unknown. To obtain an understanding of T. parva in Malawi, we performed population genetics analysis of T. parva populations in cattle vaccinated with the Muguga cocktail live vaccine and non-vaccinated cattle using mini- and microsatellite markers covering all the four T. parva chromosomes. The T. parva Muguga strain was included in this study as a reference strain. Linkage disequilibrium was observed when all samples were treated as a single population. There was sub-structuring among the samples as shown by the principal coordinate analysis. Majority of the samples clustered with the T. parva Muguga reference strain suggesting that the isolates in Malawi are closely related to the vaccine component, which support the current use of Muguga cocktail vaccine to control ECF. The clustering of samples from non-endemic southern region with those from endemic central region suggests expansion of the distribution of T. parva in Malawi.

The causative agents of fascioliasis in animals and humans: Parthenogenetic Fasciola in Asia and other regions

Parthenogenetic Fasciola is the causative agent of fascioliasis in animals and humans and is widely distributed in Asian countries, such as Japan, South Korea, China, Vietnam, Thailand, the Philippines, Myanmar, Bangladesh, Nepal, and India. Parthenogenetic Fasciola geographically originated from central and eastern China, where it exists between the habitats of Fasciola hepatica and Fasciola gigantica; it likely appeared thousands of years ago following hybridization between F. hepatica and F. gigantica. Parthenogenetic Fasciola consists of diploids and triploids that possess nuclear genome of both F. hepatica and F. gigantica and mitochondrial genome of either F. hepatica or F. gigantica. Maternal parents of parthenogenetic Fasciola are either F. hepatica having Fh-C4 haplotype or F. gigantica having Fg-C2 haplotype in mitochondrial NADH dehydrogenase subunit 1 (ND1) nucleotide sequences. Parthenogenetic Fasciola flukes with the Fh-C4 haplotype have spread from China to South Korea and Japan, whereas the flukes with the Fg-C2 haplotype have not only spread to Korea and Japan but also southward to Vietnam, Thailand, the Philippines, Myanmar, Bangladesh, Nepal, and India. Parthenogenetic Fasciola can be distinguished from F. hepatica and F. gigantica using combinational DNA sequence analysis of nuclear phosphoenolpyruvate carboxykinase (pepck) and DNA polymerase delta (pold) along with mitochondrial ND1 markers. The establishment of parthenogenetic Fasciola is expected as follows: parthenogenetic diploids with the Fh-C4 and Fg-C2 haplotypes first appeared based on single or multiple interspecific hybridization events; subsequently, parthenogenetic triploids emerged via backcross events between the maternal parthenogenetic diploid and either paternal bisexual F. hepatica or F. gigantica. Parthenogenetic Fasciola diploids and triploids then survived for thousands of years by clonal parthenogenetic reproduction, and generated descendants with ND1 haplotypes, which were derived from the Fh-C4 and Fg-C2 due to nucleotide substitution. Thus, the emergence of parthenogenetic Fasciola may be due to extremely uncommon and accidental events. Parthenogenetic Fasciola should be treated as a new asexual hybrid species.

Brachylaima phaedusae n. sp. (Trematoda: Brachylaimidae) from door snails in Japan

The metacercarial infections of door snails (Gastropoda: Clausiliidae) with unknown species of the genus Brachylaima (Trematoda: Brachylaimidae) have recently been reported in eastern Honshu and Kyushu, Japan. A large scale snail survey was carried out to clarify their taxonomic status. From the period of 2015 to 2020, a total of 1239 land snails (768 door snails and 471 others) were collected from 32 localities in Honshu, Shikoku, and Kyushu. The resulting trematode isolates were identified as Brachylaima sp. by mitochondrial DNA barcoding. The sporocysts were found only a few from Megalophaedusa sublunellata (Clausiliidae), Tauphaedusa subaculus (Clausiliidae), and Aegista trochula (Camaenidae), while the metacercariae were frequently detected from 14 species of Clausiliidae and 2 species of other families. Although Brachylaima sp. showed a broad range of intermediate hosts, door snails seem to be very important to drive the life cycle. The gravid adults of Brachylaima sp. was experimentally raised from metacercariae using immunosuppressed mice. Morphological, phylogenetical, and ecological considerations prompted us to propose Brachylaima phaedusae n. sp. for this unknown species. The definitive hosts of the new species are completely unknown. The wide geographic distribution and high genetic diversity of the new species suggest a possibility that the definitive host is ground-foraging birds, which prefer door snails.

Genetic and seasonal variations of Trypanosoma theileri and the association of Trypanosoma theileri infection with dairy cattle productivity in Northern Japan

Trypanosoma theileri is considered a non- or low-pathogenic trypanosome that generally causes latent infection in apparently healthy cattle; however, T. theileri propagates in the bloodstream and may cause clinical disease in pregnant animals or co-infection with bovine leukemia virus or Theileria orientalis. In the current study, a monthly survey of T. theileri infection over one year was carried out in a research dairy farm in Hokkaido, Japan to determine the 1) seasonal variations in the prevalence, 2) genetic characterization of T. theileri, and 3) associations of milk and blood parameters in dairy cattle with T. theileri infection, including data of metabolic profile tests and dairy herd performance tests, using linear mixed models. We found that 1) the prevalence of T. theileri infection was significantly higher in summer and winter than in other seasons; 2) T. theileri possibly showed genetic diversity in Eastern Hokkaido; and 3) T. theileri infection was associated with significantly lower levels of blood urea nitrogen, milk protein, and solids-not-fat, which are caused by a low rumen fermentation level. This is the first study to report the negative impact of T. theileri infection in dairy cattle, and our study indicates that control of T. theileri infection can improve the productivity of dairy cattle.

Detection and molecular characteristics of Pyelosomum cochlear (Digenea: Pronocephalidae) in the urinary bladder of the green sea turtle (Chelonia mydas) in the Northwest Pacific Ocean

The genus Pyelosomum consists of parasitic flukes occurring primarily in marine turtles; Pyelosomum cochlear Looss 1899 is the only species of this genus that parasitizes the urinary bladder. In this study, we detected flukes in the urinary bladders of 20 of 88 green sea turtles (Chelonia mydas) harvested in the Ogasawara Islands, in the Northwest Pacific Ocean. We identified the flukes as P. cochlear based on detailed morphological observations and comparisons of morphometric measurements of the species reported previously. Nucleotide sequences of nuclear ribosomal 18S and 28S regions and the mitochondrial cytochrome c oxidase subunit 1 (COI) region were determined for the flukes. The 18S and 28S phylogenetic trees revealed that the species of the superfamily Pronocephaloidea, including P. cochlear, constituted a single clade, but the species of the family Pronocephalidae did not constitute a single taxon. These findings suggest that Pronocephalidae is a paraphyletic group. The COI sequences of P. cochlear exhibited high genetic diversity, suggesting that they would be useful markers to understand the genetic structure of the parasite and its evolutionary relationship with the host turtle populations. This is the first study to provide the nucleotide sequences of Pyelosomum species; these data will be available for further molecular studies of this genus and its related taxa.

Development of a multiplex PCR method for discriminating between Heterakis gallinarum, H. beramporia, and H. indica parasites of poultry

Heterakis gallinarum, H. beramporia, and H. indica are common nematodes in gallinaceous poultry in Asian countries, and the infections occasionally lead to declining health of the hosts. These three Heterakis spp. can be identified by the morphological characteristics of the male worms; however, the female worms and eggs cannot be identified because they have no reliable morphological characteristics for discrimination. In addition, H. gallinarum is a well-known vector of fetal protozoan Histomonas meleagridis, making the discrimination between these three Heterakis species important in basic and clinical veterinary parasitology. We analyzed nuclear ribosomal 18S-ITS1-5.8S-ITS2-28S DNA sequences of these three Heterakis species. The 18S, 5.8S, and 28S DNA sequences had very high homology between the species; however, the ITS1 and ITS2 sequence similarity was 68.5 %-93.2 %. H. gallinarum, H. beramporia, and H. indica were divided into separate clades in the ITS1 and ITS2-concatenated phylogenetic tree. Therefore, to develop a multiplex PCR method for discriminating between the three Heterakis species, we designed species-specific reverse primers within the ITS2 region as follows: H. gallinarum-specific HgI2-R, H. beramporia-specific HbI2-R5, and H. indica-specific HiI2-R. The multiplex PCR amplified 396-bp, 272-bp, and 482-bp fragments specific to H. gallinarum, H. beramporia, and H. indica DNA, respectively, and did not amplify the fragments using other chicken nematode DNAs such as Ascaridia galli, Oxyspirura mansoni, Dispharynx nasuta, and Cheilospirura hamulosa. These results suggest that the multiplex PCR would serve as a useful tool for identifying and diagnosing infections of H. gallinarum, H. beramporia, and H. indica in poultry.

Molecular Characterization of Ticks and Tick-Borne Pathogens in Cattle from Khartoum State and East Darfur State, Sudan

Ticks transmit many pathogens with public health and veterinary importance. Despite the wide distribution of tick-borne pathogens in Sudan, the information on the tick–pathogen relationship needs to be updated, particularly using modern molecular techniques. This cross-sectional study, conducted between September and November 2019, used morphology, PCR, and sequencing to confirm the identity of adult cattle ticks (male and female; n = 536) from Khartoum State (n = 417) and East Darfur State (n = 119). Moreover, the presence of Theileria annulata, Babesia bigemina, B. bovis, Anaplasma marginale, and Ehrlichia ruminantium was detected and confirmed in each tick using species-specific PCR or nested PCR and sequencing. The most economically important tick genera, Rhipicephalus, Hyalomma, and Amblyomma, were prevalent in the study area, and 13 different tick species were identified. The most prevalent tick species were Rhipicephalusevertsi evertsi (34.3%) and Hyalomma anatolicum (57.3%) in Khartoum State, and Rhipicephalus annulatus (27%), Rhipicephalus decoloratus (25%), and Hyalomma rufipes (29%) in East Darfur State. We detected all five pathogens in both states. To the best of our knowledge, this is the first study to report the presence of E. ruminantium, its vector Amblyomma variegatum, and B. bovis in Khartoum State. Further, this is the first report on most tick and pathogen species identified in East Darfur State. Our findings indicate the migration of some tick and pathogen species beyond their distribution areas in the country, and this consideration is necessary to develop future control strategies.

The first detection of Dicrocoelium chinensis sporocysts from the land snail Aegista vulgivaga in Gifu Prefecture, Japan

Trematodes of the genus Dicrocoelium are one of the most common parasites in ruminant animals; however, their life cycles in Japan are unclear. To find the sporocysts of D. chinensis in the natural field, we sampled 269 land snails (14 species) at a location with high level infection of sika deer in Gifu Prefecture, Honshu Island, Japan in autumn between 2017 and 2019. During the sampling period, we found mother sporocysts in the hepatopancreas of Aegista vulgivaga and Cyclophorus herklotsi. DNA barcoding based on the sequences of cytochrome c oxidase subunit 1 showed that the sporocysts from A. vulgivaga belonged to D. chinensis, indicating that this snail has potential as the first intermediate host of D. chinensis at this location.

Prevalence of Nosema species infections in Apis cerana japonica and Apis mellifera honeybees in the Tohoku region of Japan

We investigated here, the prevalence of Nosema microsporidia infections in the honeybees, Apis cerana japonica and Apis mellifera, in the Tohoku region of Japan. We detected Nosema ceranae DNA in 14 (2.8%) of 509 A. cerana japonica and in 34 (21.9%) of 155 A. mellifera honeybees from Aomori, Iwate, Akita, Yamagata, and Fukushima prefectures. Nosema apis DNA was undetectable in A. cerana japonica and A. mellifera. The unidentifiable Nosema species that genetically differed from N. apis, N. ceranae, and N. neumanni in terms of small subunit (SSU) rDNA, large subunit rDNA, and internal transcribed spacer sequences was identified in 105 (20.6%) of 509 A. cerana japonica and in 1 (0.6%) of 155 A. mellifera honeybees, and from Iwate prefecture. A phylogenetic tree based on SSU rDNA sequences showed that the Nosema sp. belonged to the same clade as N. thomsoni detected in moth and solitary bees in North America and N. pieriae found in cabbage butterfly in Turkey, which have not hitherto been detected in honeybees. The morphological characteristics of the spores should be analyzed to enable species identification of the Nosema sp.

Genetic characterization of Neospora caninum from aborted bovine fetuses in Hokkaido, Japan

Neospora caninum is one of the main causes of bovine abortions worldwide, including Japan. Nothing is known about the N. caninum population substructures in Japan, and only one isolate from a pregnant sheep has been studied to date. This study describes, for the first time, the genetic characterization of isolates of N. caninum implicated in cattle abortions in Japan. Brains from five aborted fetuses were successfully genotyped based on multilocus microsatellite markers. Assigned genotypes showed high frequencies of mixed alleles in the sequenced markers MS7 and MS10, raising concerns about the subpopulation structures of N. caninum infecting animals in Japan. Clustering analysis of the genotypes, together with those from a previous dataset, showed that five of the six genotypes were distinct from other clusters. Meanwhile, the remaining genotype, together with the sheep isolate from Japan, was grouped with those from Mexico and Spain. These preliminary data may indicate a complex transmission pattern of N. caninum in Japan via clonal spreading by vertical and horizontal transmission and geographically related population substructuring.

Molecular characterization of Ascaridia galli from Bangladesh and development of a PCR method for distinguishing A. galli from Heterakis spp

We analyzed the nuclear ribosomal internal transcribed spacer (ITS) 1 and ITS2 sequences for Bangladesh isolates of Ascaridia galli, and we determined that the sequences were unreliable as molecular markers for distinguishing A. galli from other Ascaridia species, because the sequences showed high identity with that of A. columbae. However, the ITS1 sequences were available for designing PCR primers distinguishable between Ascaridia galli and Heterakis spp. Bangladesh isolates of A. galli constituted a monophyletic clade along with other geographical isolates in the cytochrome c oxidase subunit I (COI) phylogenetic tree, however, we could not clarify the phylogenetic relationships between A. galli and other Ascaridia spp., because their available sequences in GenBank were very few. The developed PCR method using DNA from A. galli and Heterakis spp. eggs would enable differential diagnosis of the individual infections in the future.

Genetic diversity and population structure analyses based on microsatellite DNA of parthenogenetic Fasciola flukes obtained from cattle and sika deer in Japan

Understanding the population structure of Fasciola flukes in domestic and wild animals is important for determining the extent of cross-infection between them. Although the parthenogenetic Fasciola flukes in Japan have been shown to comprise five genetic types based on the ribosomal internal transcribed spacer 1 (ITS1) and mitochondrial NADH dehydrogenase subunit 1 (nad1) regions, these genetic regions are not suitable for analyzing their population structure. In the present study, the genetic diversity and population structure of the parthenogenetic Fasciola flukes in Japan were studied using microsatellite DNA, ITS1, and nad1 regions. A total of 144 parthenogenetic Fasciola flukes, obtained from cattle and sika deer in 16 localities, were individually analyzed using PCR-RFLP for ITS1, PCR-direct sequence analysis for nad1, and post-labeling PCR and capillary electrophoresis for microsatellite DNA regions. The flukes showed higher genetic diversity in the microsatellite DNA regions than ITS1 and nad1. The population structures of parthenogenetic Fasciola flukes were unclear, however, it was suggested that the flukes are more diverse populations. We hypothesized that their distribution throughout Japan is closely related to livestock movement dependent on human activity. Moreover, it is considered that cross-infection of the flukes between cattle and sika deer possibly has occurred in the past.

Development of conventional multiplex PCR method for discrimination between Dispharynx nasuta and Cheilospirura hamulosa (Nematoda: Acuariidae) parasitizing poultry

The poultry infections caused by Dispharynx nasuta and Cheilospirura hamulosa nematodes are difficult to be diagnosed by fecal examination because of their egg similarity. In this study, we analyzed DNA sequences of nuclear ribosomal 18S-ITS1-5.8S-ITS2-28S region of D. nasuta and C. hamulosa and developed conventional multiplex PCR method using species-specific primers for discriminating between the two species. The method amplified 455-bp and 319-bp fragments specific to D. nasuta and C. hamulosa, respectively, and did not produce them against the other chicken nematode species, Ascaridia galli, Oxyspirura mansoni, Heterakis gallinarum, Heterakis beramporia, and Heterakis indica, suggesting that the multiplex PCR is sensitive and available for species diagnosis.

Molecular characterization of Oxyspirura mansoni and Philophthalmus gralli collected from the eyes of domestic chickens in Bangladesh

A variety of helminths have been found in domestic chickens in Bangladesh, but little is known about their gene sequences. Here, parasitic nematodes and trematodes were collected from the eyes of domestic chickens and analyzed for their morphological and morphometric characteristics, and characterized molecularly. The helminths were identified as Oxyspirura mansoni and Philophthalmus gralli. The ITS1 and ITS2 sequences of O. mansoni were 532 bp and 306 bp in length, respectively, and showed low identity (50.7-62.7%) with those of O. petrowi and O. conjunctivalis. Furthermore, the O. mansoni CO1 sequences (393 bp) showed five haplotypes (97.5-99.5% similarity) that formed a monophyletic clade. With respect to P. gralli, the ITS1 (452 bp) and ITS2 (736 bp) sequences showed 100% similarity with the reference sequences in GenBank. Both the ND1 and CO1 phylograms showed that P. gralli from Bangladesh, Costa Rica and Peru form a monophyletic clade, distinct from the clades of P. lucipetus and P. lacrymosus. Our data show that, Philophthalmus gralli isolates from Bangladesh, Costa Rica and Peru are genetically close to each other.

Molecular characterization revealed Fasciola specimens in Ecuador are all Fasciola hepatica, none at all of Fasciola gigantica or parthenogenic Fasciola species

All 225 Fasciola flukes obtained from domestic animals (73 cattle, 7 sheep and 1 pig) of 18 distinct geographic areas in Ecuador-South America, were identified as Fasciola hepatica, based on molecular analyses of nuclear pepck and pold genes, and mitochondrial nad1gene as well as the morphological observation of sperm within the seminal vesicles. Fasciola gigantica and parthenogenic Fasciola forms endemic to Asian countries were not found in this study, although zebu cattle and water buffalos have introduced into South America from Asia; this could be due to the absence of suitable intermediate host snails. The results of pepck analysis using multiplex PCR developed previously showed that 32 of the flukes could not be confirmed as F. hepatica, suggesting that the method is unreliable for the accurate discrimination of F. hepatica, and that pepck gene of the species consists of multiple loci, not a single locus. The results of genetic diversity, phylogenetic, and network analyses based on mitochondrial nad1 sequences suggest that F. hepatica populations in South America, including Ecuador, formed from the ancestral F. hepatica individuals introduced into the continent along with anthropogenic movement of livestock infected with the species.

Serological and molecular detection of selected hemoprotozoan parasites in donkeys in West Omdurman, Khartoum State, Sudan

In Sudan, donkeys are important animals, providing transportation and income possibilities. However, the prevalence of parasites in donkeys in Sudan has not been thoroughly characterized. Accordingly, in this study, we aimed to detect selected hemoprotozoan parasites in donkeys in West Omdurman, Khartoum State, Sudan, wherein people depend mainly on donkeys for their daily life. In total, 198 blood samples collected from donkeys in a local market in West Omdurman, were screened using serological and molecular diagnostic techniques. Serologically, 52 (26.3%), 56 (28.3%), and 19 (9.6%) samples were positive for trypanosomosis using Card Agglutination Test for Trypanosoma evansi, Trypanosoma evansi crude antigen -based enzyme-linked immuno sorbent assay (ELISA) and recombinant Trypanosoma evansi GM6-4r-based ELISA, respectively. ELISA for equine piroplasmosis revealed 156 (78.8%) and 10 (5.1%)Theileria equi- and Babesia caballi-positive samples, respectively. PCR detected Trypanosoma congolense, subgenus Trypanozoon, Theileria equi, and Babesia caballi in 18 (9.1%), 77 (38.9%), 18 (9.1%), and 8 (4%) samples, respectively. Of the 77 Trypanozoon-positive samples, 35 (45.5%) were confirmed as Trypanosoma evansi type A. To our knowledge, this is the first report of detection of Trypanosoma congolense in donkeys outside of tsetse-infested areas in Sudan.

The prevalence and molecular characterization of Acarapis woodi and Varroa destructor mites in honeybees in the Tohoku region of Japan

Honeybee acarapiosis and vorrosis were designated as Notifiable Infectious Diseases in the Act on Domestic Animal Infectious Diseases Control by the Minister of Agriculture, Forestry and Fisheries of Japan in 1997. However, the prevalences of A. woodi and V. destructor in Japan, especially in the Tohoku region, have not been sufficiently elucidated. This study was designed to clarify the prevalence of A. woodi and V. destructor mites in Apis cerana japonica and Apis mellifera in the Tohoku region and the characteristics of their mitochondrial cytochrome c oxidase I (COI) DNA. Acarapis woodi mites were detected from 13.5% of A. c. japonica and 0% of A. mellifera. Aomori prefecture, Japan is a new distribution locality for A. woodi. None of the honeybees examined showed infection by V. destructor mites. The COI sequences (1638 bp) of A. woodi were identical and phylogenetically closely related to those of A. woodi from Japan and the UK, suggesting that the mite would have been introduced into Japan with A. mellifera during the last 150 years and spread throughout the country.

Infection by and Molecular Features of Learedius learedi (Digenea: Schistosomatoidea) in Green Sea Turtles (Chelonia mydas) on the Ogasawara Islands, Japan

Learedius learedi Price, 1934 , is a blood fluke found in sea turtles, and the adult fluke parasitizes the cardiovascular system of the host. In this study we surveyed 46 green sea turtles, Chelonia mydas, on the Ogasawara Islands, Japan, and blood flukes were detected in the heart and blood vessels of 26 turtles. The flukes were identified as L. learedi based on a detailed morphological description. In addition, molecular identification and characterization of the parasite were performed. The nucleotide sequences of nuclear internal transcribed spacer 2 (ITS2) regions were almost identical to those of L. learedi reported previously, but not to those of Hapalotrema spp., which is the closest related genus. The nucleotide sequences of the 28S ribosomal DNA region formed a single clade with those of the reference L. learedi in the phylogenetic tree, but not with those of Hapalotrema spp. Therefore, the nucleotide sequences of ITS2 and 28S are robust markers for distinguishing L. learedi from other species. The nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 (COI) region were analyzed to evaluate the genetic variations in L. learedi. The COI haplotypes revealed the extremely high genetic diversity of the species as well as the host turtles on the Ogasawara Islands. The haplotype frequency in the mitochondrial DNA of the green sea turtles on the Ogasawara Islands is known to be significantly different from those in other Pacific rookeries. Although the number of analyzed flukes is small in this study, no haplotype was close to that in other areas; on the basis of the data, we hypothesized that L. learedi differentiated along with the host turtles on the Ogasawara Islands.

First report of Paragonimus skrjabini miyazakii metacercariae in Geothelphusa dehaani (Sawagani) occurring in Iwate Prefecture, Japan

Paragonimiasis is an important food-borne zoonosis caused by Paragonimus flukes and is endemic to western Japan. However, there have been few epidemiological studies in the Tohoku district of northeastern Japan. In this study, Paragonimus metacercariae (mc) was detected in Geothelphusa dehaani (Japanese freshwater crab or Sawagani) in Iwate Prefecture. Out of the 207 Sawagani collected from 35 localities, 12 individuals from six localities were infected with Paragonimus mc. The mc were identified as P. skrjabini miyazakii based on the sequences of nuclear ribosomal internal transcribed spacer 2 and mitochondrial cytochrome c oxidase I. This is the first report of P. s. miyazakii mc infection in Sawagani in Iwate Prefecture.

Characterization of Echinostoma revolutum and Echinostoma robustum from ducks in Bangladesh based on morphology, nuclear ribosomal ITS2 and mitochondrial nad1 sequences

Precise discrimination of Echinostoma species within the 'revolutum' group is quite difficult because of their morphological similarities. The objective of this study was to precisely characterize the echinostomes of ducks from Bangladesh based on both morphological and molecular characteristics. Two Echinostoma species were identified: E. revolutum and E. robustum. In the phylogenetic trees (ITS2 and nad1), E. revolutum and E. robustum belonged to their respective Eurasian clade, which is distinct from the American clade. These results suggest that both species have two distinct and geographically separated lineages, Eurasian and American. Our molecular and morphological data combined with previously published data supports the synonymy of E. robustum, E. miyagawai, and E. friedi previously based on either molecular or morphological evidence. This study thus improves our understanding of species diversity of the 'revolutum' group, particularly in Asia.

Phylogenetic relationships between Dicrocoelium chinensis populations in Japan and China based on mitochondrial nad1 gene sequences

We carried out phylogenetic analyses of the relationships between Dicrocoelium chinensis populations in Japan and China using molecular markers. One hundred nine lancet flukes collected from Japan and China were identified as D. chinensis based on their testis orientation and the nucleotide sequences of their ribosomal ITS2. These flukes were analyzed phylogenetically using mitochondrial nad1 gene sequences. An analysis of molecular variance found that the percentage of variation between the countries was extremely high, indicating that the D. chinensis populations in Japan and China are differentiated genetically. D. chinensis mainly parasitizes wild sika deer, which is thought to originate in northeast Asia and to have colonized into Japan from the Eurasia continent in the Pleistocene glaciations. In addition, phylogenic analyses indicated that Japanese sika deer is genetically differentiated from Chinese population; therefore, we hypothesize that D. chinensis might have been introduced into Japan along with the migration of infected wild ruminants in the Pleistocene, and then the population became differentiated from the Chinese population. This study provides the nucleotide sequences of the nad1 gene of D. chinensis in Japan for the first time and shows that these sequences are useful for elucidating the phylogenetic relationships of the Dicrocoelium species prevalent in Asia.

First report of Fasciola larva infection in Galba truncatula (Müller, 1774) (Gastropoda, Lymnaeidae) occurring in the natural environment in Hokkaido, Japan

In Hokkaido, Japan, wild sika deer are highly infected with Fasciola flukes, suggesting that the flukes complete their life cycle via intermediate host snails and definitive host animals occurring in the natural environment. However, infected snails have been found only in cattle farms contaminated with fasciolosis. This study reports the first Fasciola larva infection in Galba truncatula snails occurring in the Shoro and Atsuma rivers in the natural environment. Molecular analysis revealed that the nad1 haplotype of the larvae was consistent with that of Fasciola adults obtained from sika deer in Hokkaido. These results indicated that Fasciola flukes complete their life cycle via G. truncatula and sika deer occurring in the natural environment.

Molecular characterization of Fasciola flukes obtained from wild sika deer and domestic cattle in Hokkaido, Japan

The number of wild sika deer (Cervus nippon yesoensis) continues to increase in Hokkaido Prefecture, Japan. The major concern for the livestock industry is the transmission of pathogens between sika deer and cattle. Fasciolosis is an important disease that can occur in both animals. The aim of this study was to examine the possible mutual transmission of this disease in Hokkaido Prefecture. A total of 105 Fasciola flukes were obtained from sika deer and 96 from domestic cattle. The Fasciola flukes in Japan are reported to possess no mature sperm. However, in this study, 14 flukes from sika deer and eight flukes from cattle contained mature sperm in their seminal vesicles. All the Fasciola flukes from the two host animals had Fh/Fg type in nuclear phosphoenolpyruvate carboxykinase (pepck) gene, with a mixed fragment pattern derived from F. hepatica and F. gigantica, which are considered to be hybrid Fasciola flukes. However, almost all the flukes had Fsp1 haplotype in NADH dehydrogenase subunit 1 (nad1) gene, indicating that their maternal lineage was F. hepatica. A new haplotype, Fsp3, was detected in one fluke obtained from cattle and differed in one nucleotide from Fsp1. Therefore, the Fasciola flukes detected in both host species had almost identical molecular characteristics. These findings suggest the mutual transmission of Fasciola flukes between sika deer and domestic cattle in Hokkaido.

Molecular characterization and phylogenetic analysis of Explanatum explanatum in India based on nucleotide sequences of ribosomal ITS2 and the mitochondrial gene nad1

The aim of this study was to analyze the phylogenetic relationship between Explanatum explanatum populations in India and other countries of the Indian subcontinent. Seventy liver amphistomes collected from four localities in India were identified as E. explanatum based on the nucleotide sequences of ribosomal ITS2. The flukes were then analyzed phylogenetically based on the nucleotide sequence of the mitochondrial gene nad1 in comparison with flukes from Bangladesh and Nepal. In the resulting phylogenetic tree, the nad1 haplotypes from India were divided into four clades, and the flukes showing the haplotypes of clades A and C were predominant in India. The haplotypes of the clades A and C have also been detected in Bangladesh and Nepal, and therefore, it seems they occur commonly throughout the Indian subcontinent. The results of AMOVA suggested that gene flow was likely to occur between E. explanatum populations in these countries. These countries are geographically close and have been historically and culturally connected to each other, and therefore, the movements of host ruminants among these countries might have been involved in the migration of the flukes and their gene flow.