Gastrointestinal Nematode Parasites Research Articles

Determining the efficacy of Red Cell® in combination with anthelmintics against gastrointestinal nematode parasitism in sheep and goats

Small ruminants are highly susceptible to infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, a blood-feeder that can cause severe anemia and death losses in untreated animals. Anecdotal evidence has suggested that short-term treatment of heavily infected animals with Red Cell®, a vitamin and mineral supplement, in combination with anthelmintic drugs may reduce morbidity and mortality. The objective of this study was to determine the effect of Red Cell® on GIN infection in small ruminants. Four experiments were conducted and comprised of a two-week trial using mixed-sex naturally parasitized hair sheep lambs or intact male Spanish goat kids housed on pasture. The treatments consisted of 30 mL Red Cell® with or without albendazole (Exp. 1, lambs), levamisole (Exp. 2, lambs and Exp. 3, goats), or moxidectin (Exp. 4, goats), the anthelmintic alone, or water only (control). Fecal and blood samples were collected from individual animals on Day 0, 7, and 14. Fecal egg counts and blood packed cell volume analyses were conducted. Overall, though anthelmintic treatments did influence FEC and PCV, there was no effect of Red Cell® treatment.

"Prevalence of Gastrointestinal Tract Nematodes Parasites in Sheep in Hawasa Town, Southern Ethiopia"

"Prevalence of Gastrointestinal Tract Nematodes Parasites in Sheep in Hawasa Town, Southern Ethiopia"

Calves gastrointestinal nematodes and Eimeria prevalence and associated risk factors in dairy farms, southern Ethiopia

Dairy production is an important component of livestock farming in Ethiopia. Nevertheless, the productivity of the sector has been impacted negatively by the morbidity and mortality of replacement animals. A Cross-sectional study was, therefore, aimed at estimating the prevalence of Nematode and Eimeria infection in calves in Hawassa, Shashemene and Arsi Negelle, southern Ethiopia. To this end, a flotation technique was used to recover Nematode egg and Eimeria oocyst from rectally collected faeces. The overall prevalence of gastrointestinal parasitic infection, Nematode and Eimeria species collectively, was 43.9% (95% CI=38.6-49.4). The estimated proportion of Nematode, Eimeria and mixed infection was 35.8%, 21.5% and 13.3%, respectively. Among the potential factors considered faecal consistency, age and study area were found to increase recovery of Nematode egg and Eimeria oocyst in faeces (p< 0.05). Area wise, the prevalence has been noted to be higher at Arsi Negelle followed by Hawassa and Shashemene (p< 0.05). Besides, younger and diarrheic calves were found more infected by Nematode and Eimeria species than their adult and non-diarrheic counterpart. Based on their morphological appearance, Strongyle type (20.3%), Trichuris (4.2%) and Ascaris (16.3%) eggs, Eimeria oocysts (21.5%) were observed. In the light of this finding, the authors would like to advise the need for strategic intervention.

Seasonal output of gastrointestinal nematode eggs and lungworm larvae in farmed wapiti and red deer of New Zealand

Gastrointestinal nematode parasites and lungworm are significant animal health issues for farmed wapiti and red deer (Cervus elaphus). Chronic infection with gastrointestinal nematodes, coupled with sporadic, often pathogenic, outbreaks of the lungworm Dictyocaulus eckerti in young deer has resulted in many farmers relying heavily on anthelmintic treatments. An improved understanding of the epidemiology of the parasites infecting farmed deer, including the sources and seasonality of pasture contamination on the farm, is essential to the development of more integrated and sustainable control programs.The numbers of strongyle nematode eggs and lungworm larvae shed by different stock classes (red and/ or wapiti mixed-age stags, mixed-age red hinds, rising 2-year-old red stags and mix-sex rising 1-year olds) were monitored monthly, across six farms located in different regions of New Zealand, from January 2018 to early 2020. Every month, 10 fresh on-pasture faecal samples were collected from each stock class and couriered overnight to the laboratory. Baermann apparatus to recover lungworm 1st-stage larvae were set up immediately on sample arrival. Faecal samples for nematode faecal egg count were stored at 4 °C until the number of strongyle eggs were counted by mini-FLOTAC. Additional information, including stocking density, grazing systems, and anthelmintic treatments, were also noted every collection month.Results indicate a relatively consistent proportion of animals within each stock class shedding low numbers of both gastrointestinal nematode eggs (about 75 %) and lungworm larvae (about 50 %) all year round. There was little apparent seasonality and few differences between farms (location). Further, the average number of eggs/larvae shed was also relatively constant across seasons and locations, within each stock class. Interestingly, there was little correlation between lungworm larval counts and egg counts suggesting that the same animals were not consistently shedding both parasites.The data indicate that in the presence of regular anthelmintic treatments to young deer (< 1 year old), the adult stock groups constitute a potentially significant source of pasture contamination, and hence future infection. However, these data do not incorporate the seasonal effects of weather on egg/larval development, nor the number of animals of each stock class on the farms. Incorporation of these variables will be necessary to identify the sources and timing of subsequent infection. This work is currently underway.

Anthelminthic resistance of gastrointestinal nematode parasites of West African Dwarf goats in Ikwuano LGA, Abia State, Nigeria

Goat production in Nigeria has faced a major constraint resulting from parasitic infections, notably the parasitic gastrointestinal (GI) nematode which has resulted in high morbidity, mortality, high cost of treatment and high economic losses. Another problem encountered in the treatment of gastrointestinal nematode infection is anthelmintic resistance, hence, the need to investigate the anthelmintic resistance status of GI nematodes of West African Dwarf (WAD) goats in Ikwuano area of Abia State, Nigeria. A faecal egg count reduction test (FECRT) was carried out in naturally infected WAD goats. A total of 60 WAD goats were randomly assigned into 3 groups of 20 WAD goats in each group and screened for GI nematode eggs. Group A treated with ivermectin, group B was treated with levamisole and group C was treated with fenbendazole. The percentage reductions in FEC in male and female WAD goats in ivermectin treated group were 72.42% and 67.98%, Levamisole treated group were 61.67% and 65.22% in male and female WAD goats respectively and 59.50% and 52.63% for male and female in fenbendazole treated group. The percentage reduction of FEC in young and Adult WAD goats treated with ivermectin were 63.05% and 70.52%, and 58.08% and 67.04% for levamisole treated group respectively, while fenbendazole treated group had 60.03 and 54.08% reduction respectively. Resistance was observed in all the anthelmintic drugs used, which poses a huge threat to livestock production in the study area.

Nanoparticles as Alternatives for the Control of Haemonchus contortus: A Systematic Approach to Unveil New Anti-haemonchiasis Agents

Haemonchus contortus is an infectious gastrointestinal nematode parasite of small ruminants. This study addresses the in vitro/in vivo anti-haemonchiasis potential, toxicological effects, and mechanism of action of nanoparticles. Online databases were used to search and retrieve the published literature (2000 to 2021). A total of 18 articles were selected and reviewed, out of which, 13 (72.2%) studies reported in vitro, 9 (50.0%) in vivo, and 4 (22.2%) both in vitro/in vivo efficacy of different nanoparticles. Mostly, organic nanoparticles (77.7%) were used including polymeric (85.7%) and lipid nanoparticles (14.3%). The highest efficacy, in vitro, of 100% resulted from using encapsulated bromelain against eggs, larvae, and adult worm mortality at 4, 2, and 1 mg/ml, respectively. While in vivo, encapsulated Eucalyptus staigeriana oil reduced worm burden by 83.75% and encapsulated Cymbopogon citratus nano-emulsion by 83.1%. Encapsulated bromelain, encapsulated Eucalyptus staigeriana oil, and encapsulated Cymbopogon citratus nano-emulsion were safe and non-toxic in vivo. Encapsulated bromelain damaged the cuticle, caused paralysis, and death. Nanoparticles could be a potential source for developing novel anthelmintic drugs to overcome the emerging issue of anthelmintic resistance in H. contortus. Studies on molecular effects, toxicological consequences, and different pharmacological targets of nanoparticles are required in future research.

In Vitro Nematocidal Properties from Two Extracts: Lippia graveolens Leaves and Delonix regia Flowers Against Eggs and Infective Larvae of Haemonchus contortus.

The objective of this study was to assay the ovicidal and larvicidal effects of two hydroalcoholic extracts (HA-E) and their aqueous fractions (Aq-F) and organic fractions (EtOAc-F) from Lippia graveolens (leaves) and Delonix regia (flowers) against the parasitic nematode Haemonchus contortus. The egg hatching inhibition test (% EHI) and mortality of infective larvae (% mortality) were used as biological models. The treatments of each plant (mg/mL, % EHI, and % mortality) were assigned as follows: HA-E (12.5-50, EHI; 25-200, mortality), Aq-F (6.25-25.00, EHI; 12.5-50, mortality), EtOAc-F (0.37-25, EHI; 3.12-50, mortality), negative controls (distilled water and methanol at 2% and 4%), and positive control (ivermectin at 5 mg/mL). Data were analyzed using a completely randomized design through an analysis of variance, considering the EHI and mortality percentages as the response variables. To identify the secondary metabolites, both plants were subjected to qualitative chemical analysis and HPLC. The results showed that both plants exhibited highly ovicidal and larvicidal effects. The bipartition in each HA extract allowed the increase of the anthelmintic effect in EtOAc-F, achieving a total ovicidal activity at 1.56 mg/mL and a larvicidal effect higher than 90% at 25 mg/mL. The qualitative chemical profile of both vegetal species identified alkaloids, flavonoids, condensed tannins, terpenes, and saponins. These results suggest that either L. graveolens leaves or D. regia flowers could be potential candidates for the control of parasitic gastrointestinal nematodes in small ruminants. However, in vivo studies with experimental animals to evaluate their possible toxicity and anthelmintic effect are necessary.

Associations between MHC class II variation and phenotypic traits in a free-living sheep population.

Pathogen-mediated selection (PMS) is thought to maintain the high level of allelic diversity observed in the major histocompatibility complex (MHC) class II genes. A comprehensive way to demonstrate contemporary selection is to examine associations between MHC variation and individual fitness. As individual fitness is hard to measure, many studies examine associations between MHC variation and phenotypic traits, including direct or indirect measures of adaptive immunity thought to contribute to fitness. Here, we tested associations between MHC class II variation and five phenotypic traits measured in free-living sheep captured in August: weight, strongyle faecal egg count, and plasma IgA, IgE and IgG immunoglobulin titres against the gastrointestinal nematode parasite Teladorsagia circumcincta. We found no association between MHC class II variation and weight or strongyle faecal egg count. We did, however, find associations between MHC class II variation and immunoglobulin levels which varied with isotype, age and sex. Our results suggest associations between MHC and phenotypic traits are more likely to be found for traits more closely associated with pathogen defence than integrative traits such as bodyweight and highlight the association between MHC variation and antibodies in wild populations.

Morphological and histopathological studies of Thelandros chalcidae (Oxyuroidea: Pharyngodonidae) infecting Chalcides ocellatus from Egypt

BackgroundThelandros (Pharyngodonidae) is a gastrointestinal nematode parasite with a life cycle including lizards as main hosts. Thelandros chalcidae collected from the large intestine of the Egyptian ocellated skink, Chalcides ocellatus were described and illustrated by light and scanning electron microscopes. Seven out of fifteen (46.66%) of the examined lizards were found to be naturally infected. Also, host intestinal tissues were evaluated from hematoxylin/eosin-stained sections to describe any histopathological changes.ResultsMicroscopic examinations revealed that the recovered pharyngodonid species characterized by mouth with triangular opening and surrounded by six simple lips, the cuticle had regular transverse annulations extending from the posterior margin of the lips to the end of the body. Male was cylindrical with distinct truncated posterior end and measured 1.59–1.86 (1.64 ± 0.10) long and 0.29–0.37 (0.32 ± 0.01) in maximum width at the level of mid-body. Female measured 1.72–2.43 (1.85 ± 0.2) long and 0.36–0.49 (0.42 ± 0.01) maximum width at the mid-body level, terminated posteriorly in a short, stout spike. Histological studies observed structural alterations represented by leukocytic infiltration, villi atrophy, and muscularis degeneration. These changes were indicative of inflammatory and degenerative reaction due to Thelandros chalcidae infection.ConclusionThe present morphological study revealed that the recovered pharyngodonid species was Thelandros chalcidae causing pathological alterations in Chalcides ocellatus intestinal tissues.

The ATP bioluminescence assay: a new application and optimization for viability testing in the parasitic nematode Haemonchus contortus

The parasitic gastrointestinal nematode Haemonchus contortus causes serious economic losses to agriculture due to infection and disease in small ruminant livestock. The development of new therapies requires appropriate viability testing, with methods nowadays relying on larval motility or development using procedures that involve microscopy. None of the existing biochemical methods, however, are performed in adults, the target stage of the anthelmintic compounds. Here we present a new test for the viability of H. contortus adults and exsheathed third-stage larvae which is based on a bioluminescent assay of ATP content normalized to total protein concentration measured using bicinchoninic acid. All the procedure steps were optimized to achieve maximal sensitivity and robustness. This novel method can be used as a complementary assay for the phenotypic screening of new compounds with potential antinematode activity in exsheathed third-stage larvae and in adult males. Additionally, it might be used for the detection of drug-resistant isolates.

Evaluation of resistance to gastrointestinal helminth nematodes in two naturally infected indigenous Nigerian goat breeds.

Tropical goat breeds often have at least modest resistance to gastrointestinal nematode parasites (GIN), but enhancement of GIN resistance is important for breed improvement. This study compared changes in fecal egg count (FEC), packed cell volume, and body weight in Red Sokoto (RS) and Sahelian (SH) male and female weaner kids and adult goats. The RS is found throughout Nigeria, but the SH is found only in the arid Sahel. Goats were evaluated fortnightly for 20 times (MT) under normal grazing conditions and natural GIN infection over 9.5months, beginning in the dry season (November) and ending at the end of the subsequent wet season (August). Animals were dewormed at the start of the study and during the rainy season (MT 18). Breed differences in FEC and PCV were not observed in weaners. Weaner females had lower FEC than males but were rapidly re-infected after deworming, perhaps in association with attainment of puberty. Adult SH goats of both sexes had lower FEC than RS goats in MT 8 through 17, suggesting a stronger acquired immune response. The FEC in lactating females of both breeds increased rapidly after deworming, to ≥ 3000 eggs per gram of feces at MT 19 and 20. The optimal time to evaluate GIN resistance in weaners was during the early rainy season, but the decision to focus on the initial high FEC near MT 15 or wait until mobilization of the acquired immune response near MT 17 requires further consideration.

Study on Prevalence of Major Gastrointestinal Nematodes of Sheep in Wayu Tuka and Diga District, Oromia Regional State

Aim This study was devised to be conducted to determine the prevalence and identify the major gastrointestinal nematode parasites based on fecal examination. Methods A cross-sectional study was carried out to determine the prevalence and associated factors with ovine gastrointestinal nematode infestation by fecal examination of 384 sheep from Wayu Tuka and Diga district, Eastern Oromia regional state. Results Out of the total 384 sampled sheep, 169 (44.0%) had been infected with gastrointestinal nematode parasite. Haemonchus species were the most frequently (20.8%) recovered nematode eggs followed by Trichostrongylus (13.0%) and Nematodirus (10.2%). There was no significant difference (p&gt;0.05) in prevalence between age groups and sex. Sheep with poor body condition had a significantly higher prevalence of gastrointestinal nematode parasite (p&lt;0.05) than those sheep in moderate or good body condition. There was no significant association between the gastrointestinal nematode infection in animals of different ages and sex groups. Conclusion The study shows that the gastrointestinal nematode parasite was a major important health problem and impact on the production of sheep in the study area. Therefore, a detailed study should be conducted to identify the parasite at the species level and special consideration should be taken on the management of sheep in poor body condition to reduce the burden of gastrointestinal nematodes.

Characterizing parasitic nematode faunas in faeces and soil using DNA metabarcoding

BackgroundGastrointestinal parasitic nematodes can impact fecundity, development, behaviour, and survival in wild vertebrate populations. Conventional monitoring of gastrointestinal parasitic nematodes in wild populations involves morphological identification of eggs, larvae, and adults from faeces or intestinal samples. Adult worms are typically required for species-level identification, meaning intestinal material from dead animals is needed to characterize the nematode community with high taxonomic resolution. DNA metabarcoding of environmental samples is increasingly used for time- and cost-effective, high-throughput biodiversity monitoring of small-bodied organisms, including parasite communities. Here, we evaluate the potential of DNA metabarcoding of faeces and soil samples for non-invasive monitoring of gastrointestinal parasitic nematode communities in a wild ruminant population.MethodsFaeces and intestines were collected from a population of wild reindeer, and soil was collected both from areas showing signs of animal congregation, as well as areas with no signs of animal activity. Gastrointestinal parasitic nematode faunas were characterized using traditional morphological methods that involve flotation and sedimentation steps to concentrate nematode biomass, as well as using DNA metabarcoding. DNA metabarcoding was conducted on bulk samples, in addition to samples having undergone sedimentation and flotation treatments.ResultsDNA metabarcoding and morphological approaches were largely congruent, recovering similar nematode faunas from all samples. However, metabarcoding provided higher-resolution taxonomic data than morphological identification in both faeces and soil samples. Although concentration of nematode biomass by sedimentation or flotation prior to DNA metabarcoding reduced non-target amplification and increased the diversity of sequence variants recovered from each sample, the pretreatments did not improve species detection rates in soil and faeces samples.ConclusionsDNA metabarcoding of bulk faeces samples is a non-invasive, time- and cost-effective method for assessing parasitic nematode populations that provides data with comparable taxonomic resolution to morphological methods that depend on parasitological investigations of dead animals. The successful detection of parasitic gastrointestinal nematodes from soils demonstrates the utility of this approach for mapping distribution and occurrences of the free-living stages of gastrointestinal parasitic nematodes.Graphical abstract

Evaluation of cross-grazing deer with sheep or cattle, as means to reduces anthelmintic usage to control gastrointestinal and pulmonary nematodes in farmed red deer (Cervus elaphus) in New Zealand

Recent reports indicate that gastrointestinal nematodes (GIN) are contributing to significant losses in deer productivity and that anthelmintic resistance has become an issue of concern for deer farmers in New Zealand. The aim of this study was to evaluate cross-grazing of deer with sheep or cattle as an aid for control of gastrointestinal and pulmonary nematode parasites of farmed red deer (Cervus elaphus) in New Zealand. This was a field study replicated over two years (2012 and 2013) for 16 weeks each year at two locations (Massey University, Palmerston North and Invermay AgResearch Centre, Mosgiel). Each farm replicate included four groups (19–20 deer) at each location: red deer cross-grazing with cattle (Deer/Cattle); red deer cross-grazing with sheep (Deer/Sheep); red deer grazing on their own (DeerOwn); and red deer grazing on their own and treated with anthelmintics every two weeks to suppress worm burdens, as a positive control (DeerSup). The key outcome was the number of anthelmintic treatments (AT) given to deer. The decision to treat individual resident deer in Deer/Cattle, Deer/Sheep and DeerOwn groups was based on “trigger” criteria including faecal egg count (FEC)≥250 eggs/g or Dictyocaulus faecal larval count (FLC)≥100 larvae/g or when growth rate was less than 80 % of the mean of the DeerSup group in the previous two weeks. In addition, to quantify the species of parasites cycling in each group, sets of three “tracer” deer were introduced to graze with each group at the mid-point and again at the end of each 16 week period in both years at both locations. Least squares means (LSM) of the number of AT given per animal for Deer/Sheep (3.4) and DeerOwn (3.3) groups were significantly higher than for the Deer/Cattle (2.7) group (p < 0.001). In tracer animals, the LSM of abomasal Trichostrongylus spp. were significantly fewer in the DeerOwn (17), Deer/Cattle (37) and DeerSup (54) groups than in the Deer/Sheep (952; p < 0.001) group. The LSM of the nematodes in the subfamily Ostertagiinae (=Ostertagia-type) were significantly more in the DeerOwn (1950) than in Deer/Sheep (370; p = 0.003) and DeerSup (238; p < 0.001) groups, but the number in the Deer/Cattle group (689) was not different to DeerOwn (p> 0.05). The LSM of lungworm were fewer in Deer/Sheep (3), Deer/Cattle (4) and DeerSup (3; p < 0.001) groups than in DeerOwn (40) group. The Deer/Cattle and DeerSup groups had significantly higher LSM of liveweight gain over the 16 weeks (p < 0.001) than the other two groups. This study demonstrated that cross-grazing with either sheep or cattle aided control of lungworm and gastrointestinal nematodes in young deer during autumn. However, the advantages varied between the use of sheep or cattle and in the ability to control different species of parasites.

New Insights into Anthelmintic Mechanisms of Action of a Synthetic Peptide: An Ultrastructural and Nanomechanical Approach.

Resistant nematodes are not affected by the most common drugs commercially available. In the search for new anthelmintics, peptides have been investigated. Here, a linear synthetic peptide named RcAlb-PepIII bioinspired from the antimicrobial protein Rc-2S-Alb was designed, synthesized, and tested against barber pole worm Haemonchus contortus. The physicochemical properties of the peptide, the 3D structure model, the egg hatch inhibition, and larval development inhibition of H. contortus were carried out. Additionally, the ultrastructure of the nematode after treatment with the peptide was evaluated by atomic force microscopy. The RcAlb-PepIII inhibited the larval development of H. contortus with an EC50 of 90 µM and did not affect egg hatch. Atomic force microscopy reveals the high affinity of RcAlb-PepIII with the cuticle of H. contortus in the L2 stage. It also shows the deposition of RcAlb-PepIII onto the surface of the cuticle, forming a structure similar to a film that reduces the roughness and mean square roughness (Rq) of it. In conclusion, the bioinspired RcAlb-PepIII has the potential to be used as a new anthelmintic compound to control gastrointestinal nematode parasites.

Repeated, drug-truncated infections with Ostertagia ostertagi elicit strong humoral and cell-mediated immune responses and confer partial protection in cattle

Bovine ostertagiasis causes significant production losses to the cattle industry. Protective immunity induced by natural infection is slow to develop and anthelmintic resistance is rapidly developing. There is a need to advance alternatives for control of gastrointestinal nematode parasites. The present study investigated the effects of repeated, drug-truncated infections (rDTI) on development of protective immunity and attenuation of a challenge infection by O. ostertagi. Helminth-free calves were randomly assigned to either a rDTI or a control group (n = 5). The rDTI group received daily oral infections of 5000 Ostertagia L3 for 5 consecutive days, then were drug-treated on 14 and 15 days post infection (dpi), to attenuate O. ostertagi at the late fourth larval (L4) through young adult stages. DTI was repeated 3 weeks after the drug treatment. A total of 5 DTIs were administered to the DTI-treated animals. Non-DTI-treated, control animals received tap water as infection control. All animals were drug-treated at the same time. Animals were challenge-infected 4 weeks following the final round of rDTI. The results show that eggs per gram of feces (EPG) in the rDTI group were significantly reduced (P < 0.05) from 21 to 39 dpi, with an overall reduction in cumulative EPG. The control group exhibited reduced (P = 0.0564) average weight gains when compared to those of the rDTI group during weeks 4–5 post infection, a period coinciding with peak EPG output of control animals. Antigen-specific IgG, IgE and IgA responses were detected after the 2nd DTI, and stronger antibody recall responses were elicited by challenge infection. High levels of antigen-specific peripheral blood mononuclear cell (PBMC)/T cell proliferation to whole worm and excretory-secretory (ES) antigens were detected in rDTI-treated animals. These data indicate that partial protective immunity against ostertagiasis, involving cell-mediated and humoral responses, can be attained by rDTI which allowed for maximal antigen exposure from staggered parasitic developmental stages. The data suggest that rDTI can be used as a model to study host-parasite interactions and identify parasite antigens responsible for eliciting host protective immune responses.

Antinematode Activity of Abomasum Bacterial Culture Filtrates against Haemonchus contortus in Small Ruminants.

Simple SummaryHaemonchus contortus is an important gastrointestinal nematode parasite of the tropical and sub-tropical regions that cause haemonchosis in small ruminants like goats and sheep. It causes low production, reduced growth and may cause death of the infected animals. Due to the resistance development and environmental issues, the use of anthelmintics can be replaced with biological control, which is an environment friendly alternative. In the present study, three bacteria viz; Comamonas testosteroni, C. jiangduensis and Pseudomonas weihenstephanesis showed significant effect on nematode mortality and egg hatch inhibition. It was also observed that the anthelmintic activity of these bacteria was dose dependent, where 100% bacterial metabolite concentration showed the highest activity. It is suggested that these bacteria may included in the integrated nematode management.Haemonchosis is a parasitic disease of small ruminants that adversely affects livestock production. Haemonchus contortus is one of the most prevalent nematode parasites that infect the abomasum of small ruminants. This parasite reduces milk production, overall growth and sometimes causes the death of the infected animals. The evaluation of the biocontrol potential of some abomasum bacterial isolates against H. contortus is investigated in this study. Out of which, three isolates—Comamonas testosteroni, Comamonas jiangduensis, Pseudomonas weihenstephanesis—show significant effect against the nematode L3, adult, and egg hatch inhibition assays. Various concentrations of metabolites from these bacteria are prepared and applied in different treatments compared with control. In the case of adult mortality assay, 50% metabolites of C. testosteroni and P. weihenstephanesis show 46% adult mortality, whereas C. jiangduensis shows 40% mortality. It is observed that decreasing the concentration of bacterial metabolite, lowers nematode mortality. The minimum nematode mortality rate is recorded at the lowest filtrates concentration of all the bacterial isolates. The same trend is observed in egg hatch inhibition assay, where the higher concentration of bacterial culture filtrates shows 100% inhibition of H. contortus egg. It is concluded that the effect of bacterial culture filtrates against H. contortus is dose-dependent for their activity against nematode L3, adult, and inhibition of egg hatchment.

Formulation of the nematophagous fungus Duddingtonia flagrans in the control of equine gastrointestinal parasitic nematodes

Equine gastrointestinal nematodiosis contributes to the lower productivity of these animals. There are growing reports of the emergence of nematodes resistant to the drugs used for decades in anthelmintic treatments. An alternative to the emergence of resistance may be the use of nematophagous fungi as a complementary method of treatment. Therefore, the objective was to evaluate the effects of the use of the product Bioverm® as a carrier of Duddingtonia flagrans, on pasture contamination level and equine parasitic burden. Sixteen mares were used, divided into two groups, one control and one treated, in which the treated animals received a dose of 1 g of Bioverm®, containing 105 chlamydospores per gram of the commercial product for each 10 kg of body weight, per day, for six months. Efficacy was evaluated by count of eggs per gram of faeces (EPG), coproculture and larval count on pastures and its correlation with climate, as well as weight gain evaluation. During the study, a significant influence of the formulation on weight gain and EPG was observed. The recovery of larvae from coprocultures revealed the predominance of small over large strongyles. There was a significant difference (p < 0.05) between the averages of the number of larvae of small strongyles recovered in the pasture at a distance of 0–20 cm from the faeces of treated and control groups. A correlation was also observed between the number of larvae recovered from the pasture and the average temperature during the experimental period, mainly in August and September. The ingestion of Bioverm® enhances the biological control of gastrointestinal nematodes of pasturing horses.

Epidemiological Studies on Nematode Parasites of Domestic Geese (Anser anser f. domesticus) and First Molecular Identification and Phylogenetic Analysis of Heterakis dispar (Schrank, 1790) in Egypt.

Gastrointestinal nematodes are one of the most important constraints of poor geese health and productivity, in addition to being involved in great economic losses for various poultry sectors. This study primarily aimed at determining the epidemiological profile and risk factors associated with the occurrence of gastrointestinal (GI) nematode parasites in geese in Egypt. The phylogenetic relationships between heterakids were the second aim. For achieving these aims, a total 180 of intestinal samples were screened for the presence of gastrointestinal nematodes over a period of one year from December 2018 to November 2019. Furthermore, A PCR-based DNA sequencing of the mitochondrial NADH dehydrogenase subunit1 gene (nad1) was conducted for characterization of adult Heterakis dispar. The current search revealed that the overall prevalence was 33.33% (60/180). Five species of nematode species was encountered in this study, namely Capillaria spp., Heterakis gallinarum (Schrank, 1788), Ascaridia galli (Schrank, 1788), Subulura brumpti (Lopez-Neyra, 1922) and Heterakis dispar (Schrank, 1790). A positive relationship was found between the prevalence of nematode infection and age of tested geese revealing that the high prevalence was found in adults rather than young birds (P = 0.03). Moreover, there was no significant difference in the prevalence of nematode infection between male and female geese (P > 0.05). Also, there was strong significant seasonal trends in the prevalence of the recovered helminths with the maximum infection was observed in summer season and lowest in winter (P = 0.002). The BLAST analysis of H. dispar nad1 sequence showed a 96.4% similarity with the sequences of H. dispar Heilongjiang. It also showed a lower similarity to the mitochondrial gene sequences of H. gallinarum (84.4%). This is the first molecular identification and report of genetic diversity of Heterakis dispar in geese from Egypt. The current finding initially provides a concise account of knowledge about the epidemiology of gastrointestinal nematodes infecting geese and are considered as a starting point for the implementation of appropriate control and prophylactic schemes for GIT nematodiasis. It also confirms the potential uses of genetic techniques for taxonomic studies of different parasites.

Effects of Medicinal Plants and Organic Selenium against Ovine Haemonchosis.

Simple SummaryMaintaining high productivity in small ruminants is hindered by infection with the parasitic gastrointestinal nematode (GIN) Haemonchus contortus. There is an increasing interest to find alternative treatments for controlling GINs due to the rapid development of resistance to synthetic anthelmintics. Supplementary feeding of plant nutraceuticals or mineral supplements may contribute to improving the resilience of lambs. The trace element selenium and vitamin E act synergistically as antioxidants in circulation, but the natural occurrence of selenium is very low in the soil, grain, and roughage. The aim of this study was therefore to determine the long-term effects of medicinal plants and organic selenium in lambs experimentally infected with H. contortus. The results indicated that both supplements favorably affected the infected lambs and may provide a new approach to controlling haemonchosis in small ruminants.The objective of this study was to determine the effect of traditional medicinal plants typical to Central Europe as well as organic selenium on increasing the resistance of lambs to gastrointestinal nematode (GIN) infection with Haemonchus contortus. 21 female lambs were infected with third-stage larvae of H. contortus on the day (D) 0 and re-infected on D49 and D77. The animals were divided into three groups based on a treatment diet: a basal diet (control), a diet enriched with dry plants (Herbmix), and a diet enriched with selenized yeast (Selplex). The number of eggs per gram (EPG) of feces was quantified on D21, D28, D35, D42, D49, D56, D63, D70, D77, D84, D91, D98, D105, D112, and D119. The mean reductions in EPG on D28 were 43.4 and 28.6% for Selplex and Herbmix, respectively. The reduction in egg output was nearly uniform throughout the experiment for Selplex. However, for Herbmix the mean reduction was only 19.8% up to D91 and 46.1% after D91. Glutathione peroxidase activity in the blood from D35 to D98 was two to three-fold higher for Selplex than the other groups. Both supplements slowed the dynamics of GIN infection and gradually increased the resistance of lambs against ovine haemonchosis.