Trematode Prevalence Research Articles

Распределение очагов инвазии литоральных моллюсков партенитами и личинками трематод в губах и заливах Мурманского побережья в мае–июне 2021 года

Species composition and geographical variation in the distribution of digenean parthenite and larvae in intertidal snails in the littoral zones along the Murmansk coast were examined. Four species of littoral gastropods (Littorina saxatilis, L. obtusata, L. littorea and Nucella lapillus) were investigated. We found 10 species of digeneans, of which 9 have marine birds as a final host. The exception was Podocotyle atomon which uses fish as a definitive host. Larvae of trematode Microphallus pygmaeus, M. piriformes and Podocotyle atomon are found everywhere on the Murmansk coast. The richest helminth fauna were recorded in the Kola Bay and in Ivanovskaya Bay, the poorest helminth fauna were recorded in Dvorovaya Bay. No pronounced trends in distribution of infection foci were noted. Trematode prevalence appears to be predominantly determined by local site condition favoring or hindering final host (birds and fishes) abundance.

Prevalence and distribution of trematodes hosted by Bithynia siamensis in Southern Thailand.

This study aimed to investigate the occurrence of larval trematode infections in bithyniid snails across five provinces in southern Thailand. A total of 1,413 Bithynia siamensis snails were collected between October 2021 and October 2022 using handpicking and scooping methods. Among these, 844 were identified as B. s. siamensis and 569 as B. s. goniomphalos. The snail samples were examined for parasitic infections in the laboratory using shedding and crushing methods. Among the 27 sampling sites, snails from 6 sites were infected with various trematode species (infection rate: 4.95%, 70/1,413). Evaluation of the morphological and internal organ characteristics of the cercariae allowed for the categorization of the trematodes into five species of trematodes (belonging to four families). The identified species included Echinochasmus pelecani (family: Echinostomatidae), Echinostoma revolutum (family: Echinostomatidae), Haematoloechus similis (family: Haematoloechidae), Loxogenoides bicolor (family Lecithodendriidae), and Stictodora tridactyla (family: Heterophyidae), and the infection rates for these species were 3.26% (46/1,413), 0.35% (5/1,413), 0.42% (6/1,413), 0.78% (11/1,413), and 0.14% (2/1,413), respectively. The cercariae from the identified trematode species were studied for DNA analysis. The phylogenetic lineage reveals relationships among the species, confirming the morphological distinctions.

Prevalence and identification of cyathocotylid trematodes infecting African catfish in Egypt.

The trematode family Cyathocotylidae infects various hosts worldwide, including birds, mammals, reptiles, and fish. However, the lack of molecular data from adult worms hinders phylogenetic, epidemiological, and host association studies. This study aims to identify the common cyathocotylid trematodes infecting African catfish in Egypt using morphological and molecular evidence. Out of 142Clarias gariepinus, 123 fish (86.6%) harbored cyathocotylid metacercariae, with a mean metacercarial intensity of 201 ± 38.5/g. Cyathocotylid metacercariae prevalence gradually rose as host size increased. Although there was no significant difference between groups, larger fish had a higher mean metacercarial intensity. The prevalence and intensity were unrelated to the fish gender. Histopathological examination of metacercariae-infected catfish revealed varying degrees of degenerative changes, including intermuscular edema leading to muscle fiber dispersion and atrophy, involving 11% to over 81% of muscle sections. We identified three cyathocotylid metacercariae and eight cyathocotylid adult species from experimental infection using morphometric and molecular data, including internal transcribed spacer (ITS) and/or mitochondrial cytochrome c oxidase subunit 1 (cox1) sequences. We determined the phylogenetic position of these cyathocotylid samples.The ITS sequence analysis linked the isolated Cyathocotylidae sp. 1 and 2 metacercariae to Prohemistomum vivax adults. Mesostephanus appendiculatoides and Paracoenogonimus ovatus were reported for the first time in Egypt. These findings may provide valuable genetic data for future molecular epidemiological and phylogenetic studies of cyathocotylid trematodes.

A sea of change: Tracing parasitic dynamics through the past millennia in the northern Adriatic, Italy

Abstract Our study uses data from Holocene core samples and modern death assemblages to understand how human-induced environmental change in the northern Adriatic Sea (Italy) may have affected parasite-host dynamics in the economically important bivalve Chamelea gallina. Thirty-one radiocarbon dates confirm temporal distinctness between the periods before and after the onset of significant human influence and confirm that trematode prevalence has decreased by an order of magnitude over the past ~2 k.y. The median number of parasite-induced pits per bivalve host and parasite aggregation has also decreased significantly, signaling a substantial decrease in the effective population size of digenean trematodes. Gaussian finite mixture modeling of pit size does not support the hypothesis of parasite extinction. Combined, these results indicate the (potentially ongoing) collapse of parasite-host interactions in C. gallina in concert with human influence on the Adriatic and its transition to an “urban sea.”

Trematode infection in ruminants and diversity of snail hosts across three agro-ecological zones in Ethiopia

The occurrence of trematodes among ruminants and their snail vectors is a major concern across various agro-ecological regions of Ethiopia. Trematodes pose significant threats to animals, causing considerable economic losses and impacting public health. In this study, we have investigated 784 ruminant fecal samples, and 520 abattoir samples, alongside the collection and identification of snail vectors from various agro-ecological regions. Fecal examinations revealed Fasciola, Paramphistomum and Schistosoma species infected 20.5% (95% CI: 17.6, 23.8), 11.7% (95% CI: 9.6, 14.2), and 6.3% (95% CI: 4.1, 9.1) of the animals, respectively. The overall prevalence of trematodes among ruminants was 28.8% (95% CI: 25.7, 32.1%), with 6.0% (95% CI: 4.3, 7.7) showing mixed infections. Fasciola was more prevalent in Asela (26%) compared to Batu (19%) and Hawassa (11.5%), while a higher proportion of animals in Batu were infected with Paramphistomum. Schistosoma eggs were detected only in Batu (12.5%), but not in other areas. Sheep and cattle exhibited higher infection rates with Fasciola, Paramphistoma, and Schistosoma compared to goats. Significant associations were observed between trematode infections and risk factors including agro-ecology, animal species, body condition score, and deworming practices. About 20.8% and 22.7% of the slaughtered animals harbored Fasciola and Paramphistomum flukes, respectively, with a higher prevalence in Asela and Hawassa abattoirs compared to Batu abattoir. Additionally, a total of 278 snails were collected from the study areas and identified as lymnae natalensis, lymnae trancatula, Biomphalaria pffiferi, Biomphlaria sudanica, and Bulinus globosus. In conclusion, the study highlights the widespread occurrence of trematode infections, emphasizing the need for feasible control measures to mitigate their economic and public health impacts.

Reproduction cycle, trematode parasitism and growth of freshwater mussel Anodonta anatina (Bivalvia: Unionidae)

Anodonta anatina, a widely distributed Eurasian freshwater mussel, has dramatically declined and listed as endangered species in IUCN Red List in some parts of the Europe. To better understand its basic biology and possible sex-dependent effects of parasitism on reproduction, we investigated the reproductive traits, trematode parasitism and growth between November 2020 and October 2021. Our data from a Finnish population indicates male-biased sex ratio and the gonadal development lasting throughout the year with a bradytictic brooding pattern. Gonadosomatic index of both sexes peaked in May and declined in June. Mature oocytes were smaller sized than those of previously studied unionids, fecundity was fairly low, and the maximum predicted lifespan was 14 years. Gonads were infected with digenean trematode parasites, Rhipidocotyle campanula being the dominant species. Interestingly, trematode infection rate was higher in females than in males. In July, when the water temperature reached its annual maximum, the trematode prevalence also peaked, which was accompanied with 16% of mussels being sterile. The trematode parasitism was thus negatively associated with reproduction, that might become even more affected if parasitism increases along with the predicted climate warming, which should be considered in possible future conservation and aquaculture efforts of this species.

An update on snail and trematode communities in the Sanyati Basin of Lake Kariba: New snail and trematode species but no human schistosomes

BackgroundThe construction of Lake Kariba brought about a rise in the incidence of schistosomiasis in its surrounding towns of Kariba (Zimbabwe) and Siavonga (Zambia). After extensive control programs in Kariba, schistosomiasis prevalence dropped significantly. The objective of this study was to revisit the same localities sampled by Chimbari et al. (2003), and provide an update on the snail community and prevalence of trematodes in the Northern shore of Lake Kariba while focusing on planorbid species. MethodsMonthly sampling of snails at 16 sites along the Northern shoreline of Lake Kariba, near Kariba town, was undertaken for one year. Minimum one specimen per morphotype was identified using molecular barcoding (sequencing a fragment of cytochrome c oxidase I subunit (COI)). The infection status of snails was assessed by Rapid Diagnostic PCRs (RD-PCR), and trematode infections were genotyped by sequencing COI and 18S rDNA markers. ResultsWe collected and identified seven snail species: Bulinus truncatus, Bulinus forskalii, Gyraulus sp., Physella acuta, Bellamya sp., Radix affinis plicatula and Pseudosuccinea columella. Physella acuta was the most abundant snail species (comprising 56.95% of the total snail count) and present at all sites. The B. truncatus population was found to be infected with the stomach fluke Carmyerius cruciformis, a Petasiger sp. and a trematode species belonging to the family Notocotylidae. No Schistosoma sp. infections were detected in our collected snail specimens. ConclusionsWe report B. truncatus as an intermediate snail host for Carmyerius cruciformis, and the presence of three non-schistosome trematode species that have not been reported in Lake Kariba before. Furthermore, we detect a possible shift in the snail community when compared to the report by Chimbari et al. (2003): this is the first record of Gyraulus sp. in Lake Kariba, and we did not observe the previously reported B. pfeifferi, B. globosus and Radix natalensis. Although this shift in snail communities might have contributed to the absence of Schistosoma spp. detection in this study, further monitoring of final and intermediate hosts across the Kariba basin is essential to prove a decrease of schistosomiasis in the area.

Prevalence of Foodborne Trematodes in Small Indigenous Fish Species in Local Markets of Phnom Penh, Cambodia.

Background: This study aimed to determine the prevalence and mean infection intensity of zoonotic foodborne trematodes (FBT) in small indigenous species (SIS) fish hosts. Materials and Methods: A total of 8630 specimens of unknown origin were collected from the markets in Phnom Penh City. Fish were identified, weighed, and separated into 20 g subsamples for each fish species, and were examined using the artificial digestion method. A total of 10 species of FBT were detected in 11 species of fish out of the 23 species of fish in the total sample. Results: All infected FBT species were intestinal flukes. No liver flukes were found. The overall prevalence of FBT infection was 29.3% ± 5.3%, and the mean intensity was 0.85 ± 1.89 metacercariae (Mc)/g. The highest FBT prevalence was observed for Isthmiophora hortensis (10.7%) and Centrocestus formosanus (7.9%). Other species identified were Diplostomum spp., Echinochasmus japonicus, Echinostoma revolutum, Echinostoma sudanense, Haplorchis taichui, Haplorchis pumilio Heterophyes spp., and Procerovum varium. The highest mean intensity was found for Diplostomum spp. (1.75 ± 3.03 Mc/g). Trichopsis vittata was one of the main species constituting the SIS in urban markets (31.72%) and showed the highest prevalence of FBT (75.0%). In addition, T. vittata had the highest diversity of intestinal flukes compared with other fish species. Amblypharyngodon chulabhornae showed the highest mean intensity. but low diversity (only two species) and low prevalence. Conclusions: T. vittata could be considered a potential indicator for targeted monitoring of FBT intestinal flukes, but A. chulabhornae could also be considered for quantitative studies considering its high mean intensity.

Prevalence of Monogenetic and Digenetic Trematodes Parasitized Fish Collected from Port Said and Ismailia Governorates, Egypt

Prevalence of Monogenetic and Digenetic Trematodes Parasitized Fish Collected from Port Said and Ismailia Governorates, Egypt

Prevalence of flukes (Fasciola hepatica and paramphistomids) in cattle in south-eastern Mexico.

The objective of this study was to determine the risk factors and prevalence of trematodes in south-eastern Mexico. The prevalence of trematodes was determined in 1010 bovines. The study was carried out from October 2018 (n=291) to December 2019 (n=719). Only in 2019 rumen and liver fluke eggs were differentiated. Faecal samples (n=311) were obtained from farms in southeast Mexico located in Tabasco, Chiapas and Campeche. In addition, the presence of flukes in liver and rumen from slaughtered cattle in abattoirs was recorded with a total of 408 samples. A logistic procedure was used to obtain the prevalence and the effect of main risk factors such as land physiography (flooded areas and hills), year, sex, animals' age and type of sample obtained (eggs in faeces and flukes). The general prevalence of flukes in cattle was 32.3 % in 2018 and 41.7 % in 2019. Prevalence of F. hepatica (liver fluke) was 18.6 % (134/719) and that of paramphistomids (rumen fluke) was 33.4 % (240/719). The infected cattle from the slaughterhouse indicated a lower prevalence of F. hepatica (1 %) and rumen fluke (26.7 %) than in farms detected by egg in faeces (41.8 % and 42.1 %, respectively). The physiographic zone was decisive in the presence of F. hepatica and rumen fluke, while sex did not represent a risk factor (P > 0.05). The environmental conditions of the Mexican southeast favour the presence of both liver and rumen fluke.

Parasite Dynamics: One Pattern and Multiple Possible Causes

How is parasitism likely to respond to anthropogenic global change? Digenean trematode prevalence among bivalve mollusk hosts in multiple coastal environments has been linked to sea-level rise on centennial and millennial time scales. Previous efforts have ruled out the influence of changing diversity, community structure, taphonomy, and salinity (fossil-based proxy) on this pattern but, until recently, we have not been able to address the role of other abiotic environmental factors. Here we present the results of stable isotope analyses (δ18O and δ13C) of the shallow marine bivalve Chamelea gallina from the Holocene and modern northern Adriatic (Italy) and trace element analysis of the estuarine bivalves Potamocorbula amurensis and Corbicula formosana from the Holocene Pearl River (China) delta using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Generalized Linear Models (GLM) of 1,297 δ18O and δ13C analyses from 57 C. gallina valves derived from 11 modern death assemblages and four Holocene core samples reveal that elevated trematode prevalence is associated with relatively negative δ18O values, relatively positive δ13C values, and a high correlation between δ18O and δ13C values. We interpret this to mean that trematode prevalence is higher during warm temperatures with minimal freshwater influence. GLMs of 3,295 LA-ICP-MS spot analyses on 48 valves from the two estuarine species (a separate GLM for each taxon), derived from 12 cored samples from Pearl River deposits, reveal a strong association between trematode prevalence and elevated Ba/Ca ratios and low species richness, which we interpret as high parasitic infestation of an oligotypic community in hypoxia-dominated environments. Taken together, the results suggest that parasitic patterns are linked to sea-level rise and geochemical insights point toward case-specific causal factors that are going to be more widespread due to anthropogenic climate change.

Paleoecological Implications of Trematode-Induced Pit Size in Chamelea Gallina from the Adriatic Sea, Italy

Gymnophallid trematodes are complex life cycle parasites that induce characteristic pits in their bivalve intermediate hosts, which serve as their sole fossil record. Previous work demonstrated that trematode prevalence increases with rising sea levels, but little has been done to investigate patterns of trematode pit size in relation to Holocene sea-level and environmental changes. Here we focus on trematode pits preserved in the bivalve Chamelea gallina from five late Holocene core samples (2510-3140 y BP) and eight modern death assemblages from the Po-Adriatic system (northern Italy). Using ImageJ, we measured 838 total pits, with 715 from the core samples and 123 from the death assemblages. The geometric mean of the primary and secondary axis was used as a proxy for trace size, which ranges from 0.117 mm to 1.708 mm. The median size of Holocene pits (0.497 mm) is significantly larger (pWilcoxon = 1.73e-05) than the median size of modern pits (0.396 mm), indicating a decrease in trematode metacercariae body size over this time. There was no significant relationship between trematode pit size and host bivalve body size and only whole, well-preserved Holocene valves were analyzed to minimize the influence of taphonomy. We interpret a change in C. gallina-trematode parasite-host interactions over the last 3 ky, which could be the result of several scenarios. Modern pits could be created by different taxa, which have smaller body sizes, or the pits could be formed by the same parasitic taxa which now may have a decreased body size, perhaps due to stress. These results, coupled with a survey of modern metacercariae sizes, suggest that the trematode pit size record can provide relevant information on parasite paleoecology and, perhaps, identity. Such information will enable more nuanced analyses of parasite-host response to environmental change in the past with an eye to the future.

COMPARATIVE STUDY OF PREVALANCE OF GASTROINTESTINAL ENDOPARASITES IN INSTITUTIONAL HERDS OF NILI RAVI BUFFALO

Gastrointestinal endoparasites have a great impact on livestock production. Currentresearch is conducted to realize the proper prevalence of gastrointestinal parasitical incursion in threeinstitutional buffalo herds in the Punjab Province. A total of 758 fecal samples were examined in farmand health laboratory, Buffalo Research Institute for a time duration of one year (July 2017 to June2018) from three institutional herds. The fecal samples collected from Livestock experiment stationBhunikey, Chak katora and Haroonabad were 227,208 and 323 respectively. Out of which 311 (41.02%) were found positive and different for parasites during the current duration of study. Thepervasiveness of different parasites including trematodes, nematodes, and diverse infestation inbuffaloes at Livestock Experiment Station Bhunikey was 25.50% (58/227), 14.90%(34/227), and4.80%(11/227) , while at Livestock Experiment Station Chak Katora it was 19.81%(64/323),17.64%(57/323) and 3.7%(12/323) percent respectively. Livestock Experiment Station Haroonabadshowed the prevalence of trematodes, nematodes and mixed infections as 24.51 %( 51/208), 6.70 %(14/208) and 4.80 %( 10/208). Maximum prevalence was observed from November to February(trematodes 24.01%, nematodes 13.81% and mixed infestation 3.4%) while minimum parasitism wasobserved from July to October (trematodes 20%, nematodes 3.5% and mixed infestation 1.2%). Thestudy that is conducted has varied results revealed that the occurrence of different gastrointestinalparasites in buffaloes is quite severe causing economical losses by reducing milk production. Bykeeping focus on this factor, a proper planned and strategic way of treatment and control program maybe designed to cover and control gastrointestinal parasitic contagions in buffaloes.

Helminths associated with terrestrial slugs in Swedish agricultural fields.

Slugs are important agricultural pests causing yearly yield losses. However, parasitizing helminths potentially could affect the size of the slug population. Here, a survey of terrestrial slug-parasitic helminths (nematodes and trematodes) was conducted for the first time in Sweden. In total, 268 terrestrial slugs were collected from 27 agricultural field edges in three seasons over 2020 and 2021 and dissected for presence of helminth parasites. Slugs belonging to the genus Arion were molecularly identified by mitochondrial DNA cytochrome c oxidase subunit I (COI) while parasites were identified using ribosomal RNA (18S). Overall, 13% of the collected slugs had helminth parasites and the likelihood of a slug being parasitized was highest in autumn. Slugs identified as Arion vulgaris were more likely to be parasitized than native slug species. The prevalence of nematodes and trematodes were similar; the dominant species found were Alloionema appendiculatum and Brachylaima thompsoni, respectively. This is the first record of the presence of these two species in Sweden.

Trematode infections in cattle and their vector snails in Rajshahi district in Bangladesh

The prevalence of snail-borne trematodes (SBTs) of cattle and their vector snails in Rajshahi district in Bangladesh were determined. A total of 380 faecal samples of cattle were collected and examined using Modified Stoll’s Ova Counting Technique. Of the smaples examined, 130 (34.2%) animals were found affected with SBTs, and the mean egg per gram of faeces (EPG) was 180.3 ± 0.8. The trematodal infections by Fasciola gigantica (1.1%), different amphistomes (32.9%), and Schistosoma spindale (0.8%) were detected among the infected cattle. The effects of age, sex, breed, and body condition of the cattle on the prevalence of SBTs were determined. The infection rate was higher in young (> 2- 4 years) cattle (46.5%), followed by calves of ≤ 2 years (35.3%), and the lowest in older (> 4 years) cattle (20%). The prevalence of trematode infections was significantly (P<0.0001) higher in females (36.5%) than in male (28.3%) cattle. The prevalence was higher in cattle with poor body condition (48.7%) than in cattle with normal body condition (24.8%). Significantly (P<0.008) higher prevalence of trematode infection was recorded in indigenous cattle (41.2%) than in cross-bred cattle (26.9%). It is suggested that SBT infection is a common problem in cattle in Rajshahi district of Bangladesh. Particular emphasis should be given to proper management and regular deworming, and sustainable control measures should be developed for the prevention of SBT infection in cattle.
 Bangl. vet. 2021. Vol. 38, No. 1-2, 24–32

DIVERSITY OF ENDOPARASITIC FAUNA INFECTING MIGRATORY BIRDS VISITING WET LAND NICHES Of PUNJAB, PAKISTAN

Birds migration is a seasonal activity and being influenced by climatic changes. Birds especially migratory birds act as vector for many pathogens including bacteria, virus, parasites and fungi. Parasites are potent pathogens having significant importance in veterinary and public health sectors. Present study was designed to check the endo-parasitic prevalence in the migratory birdpopulation of various sentinels of Punjab province, Pakistan using qualitative and quantitative microscopic examination. Overall, highest prevalence of trematodes (41.37 %) was recorded followed in order by nematodes (36.78%) and cestodes (21.83%). Non-significant association was found among the bird species; however significant variations are found among selected districts screened the bird population for endoparasitic fauna and information regarding migratory pattern and probable risk factors may help understanding the disease distribution pattern of disease from wild birds to the livestock and humans population in the selected niches of Punjab, Pakistan. The migratory nature of birds helps identify the threats for the countries involved in their routes of migration .

Prevalence of Gastrointestinal Helminth Parasites in Livestock of Kavrepalanchok

The study was carried out in Mandandeupur Municipality, Kavrepalanchok from December 2018 to May 2019. A total of 131 fecal samples of livestock were collected and examined under a microscope by using direct smear and sedimentation technique. Overall, 65.65% of samples were found positive with various types of gastrointestinal helminth parasites. Samples were collected from cows, buffaloes, and goats. Among the samples collected, the highest prevalence (76.47%) was observed among the cows and the least was found among buffaloes (57.14%) but was found statistically insignificant (p>0.05). The study revealed a prevalence of nematodes (74.47%), cestodes (7.70%) and trematodes (3.10%). The prevalence of Strongylus sp. was found highest (35.88%) and the prevalence of Cooperia sp., Hymenolepsis sp., Enterobius sp. and Fasciola sp. were found similar (0.8%). In sex wise study, both males and females of livestock were found about equally infected. In the same way, the prevalence of gastrointestinal helminths was found about similar in both the winter and summer seasons. In age wise prevalence, the adult was more infected (68.27%) with gastrointestinal helminth parasites than the young (55.55%) which was statistically insignificant (p>0.05). In the present study, single infection was found highest (47.29%) and multiple infections were found least (2.29%). The samples collected from non-dewormed livestock were found highly (71%) positive for gastrointestinal helminths. The relation between deworming and prevalence was statistically significant (p<0.05). Only 37.25% of farmers maintain the cleanliness of the shed by removing feces from the animal shed every day and only 23.53% of farmers know about the mode of transmission of gastrointestinal helminths in livestock.

Demographic pattern and digenetic trematode prevalence in Channa punctatus of Rohilkhand Region.

Fish is a worldwide food staple and a pathogen-host. Most fisheries produce commercially valuable byproducts. Fish have ectoparasitic and endoparasitic diseases. Parasites play an important role in the growth of Fish & other animals. Considering that no systematic work has been done on trematode, and fish diversity of Rohilkhand, there is no record on the impact evaluation of parasitism in the fish trematode Community. Pathogens that cause disease are always present in aquatic environments or on fish. They only become manifest as different fish diseases when the host becomes more vulnerable and allows the pathogen to multiply in the fish body. Attempts have been made to study the biodiversity of trematode parasites linked to fish in various parts of the world.

Surveillance and prevalence of gastrointestinal parasite of domestic animals in different abattoirs in Bangladesh

The study was conducted to examine the gastro-intestinal parasite infestation of animal at Gopalganj district in Bangladesh during July 2020 to June 2021. Total collected sample were 151, among them 32 cattle and goat 119. Parasites were collected directly from viscera then preserve for further analysis. Age, sex and species of the examined animals were recorded as far as practicable. Overall prevalence of nematodes, cestodes and trematodes were 62.25%, 9.27% and 50.33% respectively. The prevalence of parasites was variable with Paramphistomum spp. (58.29%), Fasciola spp 62.91%, Moniezia spp. (5.3%), Haemonchus spp. (41.06%), Trichuris spp. (3.31%), Oesophagostomum spp. (10.59%), Strongyloides spp. (2.64%), Trichostrongylus spp. (5.29%), Bunostomum spp. (5.96%), Toxocara spp. (25.17%). Parasitic in male and female exhibited no significant variations (p>0.05) between them. The infection was significantly higher in young than in adult. No significant (p>0.05) variation was observed in infection rates between cattle and goats. Asian Australas. J. Biosci. Biotechnol. 2022, 7 (2), 50-56

A relatively high zoonotic trematode prevalence in Orientogalba ollula and the developmental characteristics of isolated trematodes by experimental infection in the animal model

BackgroundFood-borne parasitic diseases decrease food safety and threaten public health. The snail species is an intermediate host for numerous human parasitic trematodes. Orientogalba ollula has been reported as intermediate hosts of many zoonotic trematodes. Here, we investigated the prevalence of zoonotic trematodes within O. ollula in Guangxi, China, and assessed their zoonotic potential.MethodsSnails were collected from 54 sites in 9 cities throughout Guangxi. The snail and trematode larvae species were determined by combining morphological characteristics and molecular markers. The trematodes prevalence and constituent ratio were calculated and compared among different habitat environments. Phylogenetic trees of the trematode species were constructed using the neighbor-joining method with nuclear internal transcribed spacer 2 (ITS2) sequences. The developmental cycles of the isolated trematodes were examined by experimental infection in ducks. The developmental characteristics of Echinostoma revolutum was recorded by dissecting infected ducklings from 1-day post infection (dpi) to 10 dpi.ResultsThe overall prevalence of trematode larvae was 22.1% (1818/8238) in O. ollula from 11 sample sites. Morphological together with molecular identification, showed that E. revolutum, Australapatemon sp., Hypoderaeum conoideum, Pharyngostomum cordatum, and Echinostoma sp. parasitized O. ollula, with the highest infection rate of E. revolutum (13.0%). However, no Fasciola larvae were detected. The trematodes prevalence and constituent ratio varied in two sub-biotypes (P < 0.01). A neighbor-joining tree analysis of ITS2 sequences resulted in distinct monophyletic clades supported by sequences from isolated larvae with high bootstrap values. Ducklings exposed to O. ollula infected with Echinostoma sp., E. revolutum, and H. conoideum larvae were successfully infected. The animal model for Echinostoma revolutum was successfully established. E. revolutum matured from larvae to adult at 10 dpi in the intestine of the duck, and the developmental characteristics of E. revolutum were characterized by the maturation of the reproductive and digestive organs at 6–8 dpi.ConclusionsThis study revealed a high prevalence of zoonotic trematodes in O. ollula from Guangxi, China. Existing trematodes infection in animals and human clinical cases, coupled with the wide geographical distribution of O. ollula, necessitate further evaluations of the potential risk of spillover of zoonotic infection from animal to human and vice versa.Graphical