Prevalence and pathological study of Paramphistomum infection in the small intestine of slaughtered ovine

Prevalence and geographical distribution of amphistomes of African wild ruminants: A scoping review

This review summarizes published records on the prevalence, species diversity, geographical distribution, mixed infections, co-infections with other trematodes and intermediate hosts (IHs) of amphistomes (rumen flukes) of wild ruminants in Africa. Literature search was conducted on Google Scholar, PubMed and JSTOR, using a combination of predetermined search terms and Boolean operators. Of the 54 African countries searched, results showed that occurrence of amphistome infections in wild ruminants have only been reported in 23 countries. A total of 38 amphistome species consisting of the following 11 genera were recorded, viz Bilatorchis, Calicophoron, Carmyerius, Choerecotyloides, Cotylophoron, Explanatum, Gastrothylax, Gigantocotyle, Leiperocotyle, Paramphistomum and Stephanopharynx. These were recorded in 39 wild ruminant species, belonging to the Bovidae family. The genus Carmyerius recorded the highest number of species (n = 13) across nine countries Africa. However, Calicophoron species (n = 9) were more widely distributed, occurring in 17 countries across all regions of Africa. Species of this genus collectively infected 27 wild ruminant species. However, at a species level, Cotylophoron cotylophorum infected the highest number of wild ruminant species. Prevalence of infection based on post-mortem examination ranged from 1.89% in African Buffalo to 100% in Defassa waterbuck from Egypt and Zambia, respectively. The most common mixed infections recorded were those between amphistomes of the same or different genus. Snail intermediate hosts (IHs) were described for 10/38 amphistome species, and these were predominantly species from Plarnobidae family. Despite the richness in diversity of amphistomes infecting wild ruminants in Africa, there is need to further confirm identity of snail IHs and the amphistome species using both morphological and molecular techniques. Furthermore, more studies are recommended to assess the burden of amphistomosis in commercially reared wildlife/game farming, mixed game and livestock farming systems in Africa.

Molecular detection of Fasciola, Schistosoma and Paramphistomum species from freshwater snails occurring in Gauteng and Free State provinces, South Africa

Trematodiases are diseases caused by snail-borne trematode parasites that infect both animals and humans. Fascioliasis, schistosomiasis and paramphistomosis are some of these diseases and they affect millions of livestock, leading to significant economic losses. The aim of the study was to document freshwater snails occurring in selected study sites in the Free State and Gauteng provinces as well as identify and detect larval trematodes that they harbour. Samples were collected from a total of five study sites within two provinces of South Africa. Morphological features were used to identify snail species and were further confirmed genetically by polymerase chain reaction (PCR), sequencing and phylogenetic analysis. The larval trematodes were also detected by PCR, PCR-Restriction Length Fragment Polymorphism (PCR-RLFP), sequencing and phylogenetic analysis. A total of 887 freshwater snails were collected from Free State (n = 343) and Gauteng (n = 544). Five different genera of snails as well as species in the Succineidae family were documented. The snails in descending order of abundance were identified as: Physa (P.) spp. (51%), Succineidae spp. (20%), Galba (G.) truncatula (12%), Pseudosuccinea (Ps.) columella (10%), Planorbella (Pl.) duryi (6%) and Bulinus (B.) truncatus (1%). Approximately 272 DNA pools were created for genetic identification of snails and detection of trematode parasites. Schistosoma species were not detected from any of the snail species. A total prevalence of 46% was obtained for Fasciola hepatica in the identified snail species across all study sites. Overall, the highest prevalence of F. hepatica was obtained in Physa species (24%), whilst the lowest was observed in B. truncatus snails (1%). Forty three percent (43%) of the snail samples were PCR positive for Paramphistomum DNA. This is the first report of P. mexicana in South Africa. Fasciola hepatica was confirmed from all obtained snail species per study site. This is the first reported detection of F. hepatica in Pl. duryi and P. mexicana snails as well as the first confirmation of natural infection from P. acuta in South Africa.

Assessment of antioxidant enzymes during the development of the digenetic trematode parasite Gastrothylax crumenifer, infecting the rumen of Indian water buffalo, Bubalus bubalis

The presence of antioxidant enzymes in helminth parasites is well known. These enzymes help the parasites to survive in their hosts by detoxifying host-generated reactive oxygen species (ROS). The literature survey reveals that most of the studies related to antioxidant enzymes in helminth parasites are restricted to the adult stage while the larval stages are neglected. The present investigation is designed to evaluate the level of antioxidant enzymes in the adult and larval stages of rumen-infecting paramphistome parasites, Gastrothylax crumenifer. The larval stages include 0-day eggs, 4-day eggs, and eggs containing mature miracidia, cercariae, and metacercariae. Antioxidant enzyme assays were performed using standard assay protocols. Our findings revealed an increasing pattern in the level of Glutathione-S-Transferase (GST), Superoxide Dismutase (SOD), Glutathione Reductase (GR), and Glutathione Peroxidase (GPx) antioxidant enzymes during the development from 0-day eggs to the adult stage. Overall analysis shows that adult worms have higher antioxidant enzyme activity as compared to the larval stages, indicating that adult flukes are more adapted to oxidative stress. It can be concluded that the miracidia, cercarial, and metacercarial developmental stages of G. crumenifer possess a considerable level of antioxidant enzymes suitable to overcome the oxidative stress encountered during the development and help them in the completion of the life cycle and survival in the definitive host.

Prevalence of Ruminant Paramphistomosis and Comparative Histopathology of the Infected Rumens in Narowal District, Punjab, Pakistan

The present study reports the prevalence of Paramphistomum spp. in small and large ruminants and their association with the histopathology of the infected rumens. A total of 384 animals were screened for Paramphistomum spp. The animals found positive for Paramphistomum spp. were divided into three groups according to the worm load/5 cm2 (G1: 10 - 20 worms/5 cm2 = Low, G2: 20 - 40 worms/5 cm2 = Medium, and G3: >41 worms/5 cm2 = High). Tissue slides were prepared from samples of the rumen (1 cm2) taken from animals positive for ruminal fluke to determine the histological parameters, including epithelial length or thickness, length and width of the ruminal papilla, and thickness of tunica submucosa and mucularis externae. The overall prevalence of Paramphistomum spp. in the ruminant population of district Narowal was 56.25 % with a significant (P < 0.05) variation among different species of ruminants. The highest prevalence was in cattle, followed in order by buffalo, goat, and sheep. Epithelium thickness was significantly correlated with parasite load in large ruminants and the most significant (P < 0.05) decrease in epithelium thickness was in Group B (31.12 ± 1.82 μm) and Group C (31.07 ± 1.68 μm) and a same trend was recorded in small ruminants. Histopathological changes due to Paramphistomum spp. are reported for the first time, which explained the histomorphological and physiological changes in Paramphistomum-infected rumens which might be associated with lowered feed efficiency and productivity in ruminants.

Prevalence, risk factors and first record of mitochondrial cox1 gene-based molecular characterization of Paramphistomum epiclitum from Pakistan

Parasitic infestations are one of the major threats to the livestock industry in Pakistan. These have a negative impact on the production of domesticated livestock species. Paramphistomes belong to the superfamily Paramphistomoidea and are involved in infecting ruminants all over the world. To date, there was no information on mitochondrial DNA-based molecular characterization of Paramphistomum epiclitum from Pakistan. To close this research gap, this study was designed to provide insights into the epidemiology of Paramphistomum species. Paramphistomum epiclitum isolates were recovered from the rumen of small ruminants slaughtered at an abattoir located in Faisalabad city and animal demographics were recorded. DNA was extracted and mitochondrial cox1 was amplified and sequenced. Prevalence was calculated along with a 95% confidence interval in various groups. The chi-square test was applied to determine the association between different variables under investigation. A phylogenetic tree was constructed based on the Bayesian method. Population diversity indices were calculated using DnaSP 4.5 software. A total of 43 mutations were observed among 7 haplotypes. Negative values of Fu's Fs values, and Tajima's D indicated population expansion. Deworming, season, and grazing were the variables that significantly correlate (p &lt; 0.05) with the prevalence of P. epiclitum. The high prevalence of P. epiclitum demonstrates that more studies are indeed needed to further understand the prevalence and distribution of P. epiclitum in definitive and all potential intermediate hosts in addition to intraspecies variation and relationship with populations from other locations.

Checklist of digenean trematodes of Iran

Digeneans are an important class of trematodes which infect variety of animals ranging from vertebrates (mainly final hosts) to invertebrates (mainly as intermediate hosts). Additionally, some of these parasites are zoonotic and one health importance. Diversity of digeneans in Iran and reports of several zoonotic cases show the importance of these parasites in this country. This is the checklist of digenean parasites reported from Iran representing a total of 118 species, from 105 genera, 43 families, 21 subfamilies, and 3 orders that are reported from 139 species of different hosts including humans. Some of the most important final number of families, genera, and species reported in Iran fauna include: Fasciolidae, Genus: Fasciola, Fasciola gigantica, Fasciola hepatica, Family: Dicrocoeliidae, Genus: Dicrocoelium, Dicrocoelium dendriticum, Family: Diplostomidae, Genus: Diplostomum, Diplostomum spathaceum, Family: Heterophyidae, Genus: Haplorchis, Haplorchis taichui, Family: Notocotylidae, Genus: Notocotylu, Notocotylus aegyptiacus, Family: Bucephalidae, Genus: Rhipidocotyle, Rhipidocotyle illense.

Prevalence and risk factors associated with amphistome parasites in cattle in Iran

Amphistomiasis, a neglected trematode infection of ruminants, has recently come up as an important reason for economic losses. The aim of this study was to determine the prevalence of bovine amphistomiasis and associated risk factors such as: age, gender, breed, season, water source, pastureland and grazing system. Between January 2016 and 2017, a total of 1,000 faecal samples and 1,000 rumens of cattle were collected from slaughterhouse of Zabol, Iran ante-mortem and post-mortem, respectively, and examined. The overall prevalence was 34.6% and 19.5% in terms of amphistome adults and eggs respectively. The identified amphistome species and their prevalence were Paramphistomumcervi (13.3%), Cotylophoroncotylophorum (19.5%), Gastrothylaxcrumenifer (5.9%) and Carmyeriusspatiosus (2.7%). The correlation between prevalence and season, age, breed, water source, pastureland and grazing system was significant (p < .0001). The presented information about the prevalence of amphistomes of cattle and individual and management risk factors can be used to design appropriate control measures.

Evaluation of anthelmintic drugs against egg development of rumen flukes recovered from cattle raised in the humid tropics of Mexico

Paramphistomosis is a parasitic disease endemic in ruminants nearly worldwide. In the present study, an in vitro screening of the main anthelmintics used in Mexico was carried out to determine the mean lethal dose for rumen fluke eggs from cattle in a humid, warm region. Rumen flukes were obtained from cattle slaughtered in the states of Tabasco and Chiapas in Mexico. Eggs were collected using a 37-μm sieve and quantified. Then, an in vitro incubation study was performed: 100 eggs were placed into the wells of polystyrene microtiter plates. Anthelmintic products were tested on the eggs at concentrations ranging from 0.0015 to 3.0 mg/ml for rafoxanide, 0.0025 to 10.20 mg/ml for nitroxinil and 0.0015 to 3 mg/ml for closantel to determine the median lethal dose (LD50) and maximum lethal dose (LD99). A control group (water) was included in each plate. Three different species of rumen flukes (Calicophoron brothriophoron, Calicophoron clavula and Paramphistomum cervi) belonging to five isolates were identified. Nitroxinil had the highest efficacy against rumen fluke eggs, with an LD50 of 0.11 to 65 μg/ml, whereas rafoxanide showed the lowest efficacy with an LD50 ranging from 500 to 1713 μg/ml. Closantel showed high variability in the LD50 among the different analysed isolates (17 to 122 μg/ml). The evaluated flukicidal drugs presented differential efficacy against the development of rumen fluke eggs. The efficacy of the drugs will vary depending on the geographical area of origin of the animals.

Environmental determinants of distribution of freshwater snails and trematode infection in the Omo Gibe River Basin, southwest Ethiopia

BACKGROUND

Determination of infection rates of snail populations is one of the basic tools for epidemiological studies of snail borne diseases. In this study, we opted to determine the trematode infection of freshwater snails in the Omo-Gibe River Basin, southwest Ethiopia.

METHODS

We collected snail samples from 130 observation sites in lakes, wetlands, rivers, reservoirs and irrigation canals surveyed during the dry season (March to May) in 2016. The snail samples were examined for trematode infections by cercarial shedding immediately after collection. Habitat conditions, water quality, human water contact practices and other human activities were assessed at each survey site. A redundancy analysis (RDA) was used to examine the relationship between cercarial infection and environmental variables. The statistical significance of eigenvalues and cercariae-environment correlations generated by the RDA were tested using Monte Carlo permutations at 499 permutations.

RESULTS

A total of 3107 snails belonging to five species were collected. The most abundant species was Biomphalaria pfeifferi, representing 66% of the total collection. Overall, 109 (3.6%) of the snails were found infected with trematodes (cercariae). Biomphalaria pfeifferi was found to be the most highly infected, accounting 85% of all infected snails. A total of eight morphologically different types of cercariae were recorded, which included: Echinostoma cercariae, brevifurcate apharyngeate distome cercariae, amphistome cercariae, brevifurcate apharyngeate monostome cercariae, xiphidiocercariae, longifurcate pharyngeate distome cercariae, strigea cercariae and unidentified cercariae. Brevifurcate apharyngeate distome cercariae, and Echinostoma cercariae were the most abundant cercariae, accounting for 36 and 34% of all infection, respectively. The mean concentration of water conductivity and 5 days biological oxygen demand were higher in irrigation canals and lake sampling points. Human activities such as open field defecation, urination, livestock grazing, farming, and swimming were highly correlated with trematode infection.

CONCLUSIONS

The abundance, occurrence and infection rates of snail species were largely influenced by water physicochemical quality, sanitation and water contact behaviour of the inhabitants. Human activities, such as open field defecation and urination, livestock grazing, farming, and swimming were important predictors of the abundance of cercariae. Therefore, awareness creation should be implemented for proper containment of excreta (urine and faeces) and reducing human and animal contacts with surface waters to reduce snail-borne disease transmission.

An in vitro confirmation of the ethonopharmacological use of Senna plants as anthelmintic against rumen fluke Paramphistomum gracile

BACKGROUND

Paramphistomosis is a pathogenic disease of domesticated ruminants, causing great economic loss in dairy industry and meat production. It is considered as a neglected tropical disease with highest prevalence throughout tropical and subtropical regions, particularly in Africa, Asia, Europe, and Australia. There are few trematocidal drugs available in the market. Most are resistant and have elevated side effects. Therefore, alternative trematocidal drugs need to discover. This study was conducted to evaluate three plants leaf extracts (from Senna alata, S. alexandrina, and S. occidentalis) as effective remedies against gastrointestinal trematode parasite (Paramphistomum gracile) of ruminants. Live adult parasites were collected in 0.1 M phosphate-buffered saline (PBS) from fresh autopsied goat's rumen. Parasites were incubated in leaf extracts of S. alata, S. alexandrina and, S. occidentalis individually and in combination (1:1) ratio at 37 ± 1°C. Treatment media contain extracts at different concentrations (10, 20 and 40 mg/mL) in 10 mL of 0.1 M PBS with 1% dimethylsulphoxide (DMSO). Parasites in control group were incubated in PBS without extract. The efficacy of three Senna extracts was evaluated on the basis of dose-dependent motility and mortality of the trematode. Immediately after paralysis, all treated parasites were collected for histology, SEM and biochemical study.

RESULTS

Dose-dependent efficacy was observed in terms of motility and time of mortality in all treated parasites after exposure in various concentrations of the Senna plant extracts. S. occidentalis and S. alexandrina showed better efficacy in combination than comparing with individual treatment groups. Histological study and scanning electron microscopic observations revealed conspicuous deformity of surface architecture in all treated parasites. Scanning electron micrographs also revealed shrinkage, vacuolization, infoldings and blebbings on the body surface of treated worms. Activities of tegumental enzymes were inhibited in all treatment groups compared to control.

CONCLUSION

The overall findings from this study revealed that all three Senna leaf extracts individually and in combination showed potential antitrematocidal activity against Paramphistomum gracile by damaging body tegument and neural propagation. Thus, this study confirmed that all three Senna extracts can be considered as a potential drug-like candidate in indigenous system of traditional medicine against trematode infections in livestock.

Calicophoron daubneyi in sheep and cattle of Sardinia, Italy

This study aimed to investigate the prevalence of paramphistomosis and confirm the species identity of rumen flukes from sheep and cattle of Sardinia (Italy), by molecular methods. From 2011 to 2014, 381 sheep and 59 cattle farms were selected and individual faecal samples were run on 15 sheep and 5 cattle for each farm, respectively. The prevalence at the slaughterhouse was calculated by examination of 356 sheep and 505 cattle. 13adult flukes collected from sheep and cattle and 5 belonging to the historical collection of Laboratory of Parasitology at the Department of Veterinary Medicine of Sassari, previously classified as Paramphistomum spp., were used for PCR amplification and sequencing of the ITS2+ rDNA. Previously classified Paramphistomum leydeni from South America were used as controls.

The EPG prevalence was 13.9 % and 55.9 % for sheep and cattle farms respectively. At slaughterhouses, paramphistomes were found in 2 % of the sheep and 10.9 % of the examined cows. Conversely to the latest reports, the sequences comparison showed that all the Sardinian rumen flukes belong to Calicophoron daubneyi.