Multiple anthelmintic resistance in gastrointestinal nematodes of small ruminants in Bangladesh

Emergence of dual drug-resistant strongylids in goats: first phenotypic and genotypic evidence from Ratchaburi Province, central Thailand

BACKGROUND

This study provides crucial insights into the prevalence and drug resistance patterns of strongylid gastrointestinal nematodes (GINs) in goats in Thailand, highlighting resistance to albendazole and levamisole. Strongylids, particularly Haemonchus sp. and Trichostrongylus sp., pose a significant threat to goat health. With the global rise of anthelmintic resistance, the detection of multidrug resistance in Thailand's goat population is concerning, given the frequent import and export of goats. This resistance challenges effective parasite control strategies. This study aimed to identify strongylid species using both morphological and genetic methods and to assess resistance to albendazole and levamisole through phenotypic and molecular approaches.

RESULTS

Fecal samples from 30 goat farms in Ratchaburi Province revealed a high prevalence of strongylid infection (87%), with Haemonchus sp. and Trichostrongylus sp. detected on 100% and 96% of farms, respectively. Phenotypic assays demonstrated significant drug resistance, with 90% and 71% of farms harboring strongylid populations resistant to albendazole and levamisole, respectively. Genotypic analysis of pooled infective larvae showed that 100% of farms had albendazole-resistant strongylid populations, with 31% homozygous and 69% heterozygous resistance, and Trichostrongylus sp. showing 48% homozygous and 52% heterozygous resistance. For levamisole resistance, 92% of farms contained resistant strongylid populations, with Haemonchus sp. exhibiting 11% homozygous and 81% heterozygous resistance.

CONCLUSIONS

This study provides the first comprehensive evaluation of phenotypic and genotypic resistance in strongylid nematodes in Ratchaburi Province, addressing a key geographical gap in Thailand's resistance data. The findings highlight the urgent need to reassess GIN management practices and develop sustainable strategies to mitigate resistance. Furthermore, these results have significant implications for transboundary livestock health, emphasizing the necessity of collaborative efforts to combat the growing challenge to anthelmintic drugs.

Cheilospirura hamulosa (Nematoda: Acuariidae) infection in indigenous chickens in Bangladesh: epidemiology, pathology and anthelmintic efficacy

Helminth infection is highly prevalent in indigenous chickens reared in semi-scavenging/ scavenging systems in Bangladesh. Here, we estimated the prevalence of gizzard worm infection in indigenous chickens, the detection of the worm-induced pathologies, the development of ex vivo cultural protocol, and anthelmintic efficacy. We randomly collected and examined 390 chickens and isolated worms from the gizzard and proventriculus. The isolated worms were identified as Cheilospirura hamulosa Diesing, 1861. The overall prevalence of C. hamulosa was 33.1% (129 out of 390). Prevalence of the worm was almost similar in both sexes but significantly (p <0.05) higher in adult chickens (44.3%) and in the summer season (47.1%). In heavy infections, C. hamulosa destroyed the muscular layer of the gizzard. The presence of brown necrotic tissues and curd-like caseous materials was detected in the affected gizzards. In severe cases, the horny lining of the gizzard was inflamed, necrotized and marked by multiple holes and brick-red colored spots. Liquefied, fetid materials oozed out from the muscular layer in extensive cases. Histopathological examination showed marked infiltrations of eosinophils. In serum-supplemented M199 and DMEM, adult C. hamulosa survived well and reproduced. Levamisole (LEV) and ivermectin (IVM) efficiently killed the worm. However, albendazole (ABZ), mebendazole (MBZ) and piperazine (PPZ) did not kill the worms. Our results suggest that C. hamulosa is highly prevalent in semi-scavenging chickens in Bangladesh. LEV and IVM can be used to treat and control the infection in chickens.

Classification of productive hair ewes using hematocrit as a marker of resistance to gastrointestinal nematodes

Background

The selection of sheep with high genetic resistance to gastrointestinal nematodes is a sustainable alternative for parasite control.

Aim

This study was performed to categorize three breeds of hair sheep according to their resistance to gastrointestinal nematodes during the peripartum period using hematocrit (HCT) and to compare these results with categorizations derived from the nematode eggs per gram of feces (EPG).

Methods

Parasitological records from two studies involving 46 Katahdin × Pelibuey and 25 Blackbelly ewes were used, along with information from pregnancy (week 22) to lactation (week 13) of a flock of 31 Pelibuey ewes. All ewes of the three breeds were naturally infected by grazing. The ewes were categorized as resistant, intermediate, or susceptible in each breed and by physiological stage (gestation or lactation) using the EPG ± three standard errors. We also categorized ewes based on their HCT ± one standard deviation.

Results

During pregnancy, resistant ewes were those with less than 257, 148, and 96 EPG for the Blackbelly, Katahdin, and Pelibuey breeds, respectively, while in lactation, resistant ewes had less than 1,587, 912, and 310 EPG, respectively. In the classification by HCT, Blackbelly ewes had values lower than 31.0%; therefore, only intermediate (HCT of 24.4%-31.0%) and susceptible ewes (HCT < 24.4%) were identified. Among the Katahdin, the resistant ewes had only 149 EPGs recorded during lactation, thereby making the classification by lactation-HTC (94 EPG) comparable to the classification by EPG. In Pelibuey ewes, classification by HCT during early lactation (week 1-4) allowed the selection of resistant ewes with higher EPG (379 EPG) compared with the EPG classification (80 EPG), but intermediate and resistant ewes had similar EPG.

Conclusion

Classification by HCT and nematode eggs per gram of feces allows the selection of ewes with resistance to gastrointestinal nematodes at the beginning of lactation.

Investigation on parasite infection and anthelmintic resistance of gastrointestinal nematodes in sheep in Hinggan league (City), China

BACKGROUND

Different areas of sheep infected with different types of parasites, all will cause serious harm to the local sheep, and the widespread use and repeated use of anthelmintics have produced different degrees of anthelmintic resistance (AR) in various regions. We re-investigated the infection of common parasites and AR of Gastrointestinal Nematodes (GINs) in sheep in Horqin Right Wing Front Banner, and first investigated the common parasite types and AR of GINs in sheep at other four areas in Hinggan league (city), China.

RESULTS

A total of 1770 fecal samples were collected from 1 prefecture-level city and 4 counties in Hinggan league, in which the infection rate of Coccidia ranged from 83.3% to 96.06%, that of Ascaris ovis ranged from 10.17% to 15.19%, that of Moniezia benedeni ranged from 0.6% to 1%, that of Moniezia expansa ranged from 0.33% to 8.15%. The infection rate of GINs was 100%, and Haemonchus contortus was still the dominant species. The AR results showed that only the closantel in Horqin Right Wing Middle Banner was low resiatant, and the other three regions had been resistant. Levamisole also occurred AR in the other four regions, the widely used ivermectin and albendazole had produced serious AR in five areas. The research shows that GINs are becoming more and more resistant to various anthelmintics, which has made the problem worse.

CONCLUSIONS

Understanding the dynamic changes of parasite infections and the development trend of AR in sheep in the region in this paper, the development trend seems to be more serious than imagined. Therefore only by deeply understanding the parasitic infections of sheep in this land can more reasonable medication guidance be carried out. It is expected to provide new ideas formore innovative, scientific and sustainable methods of preventing and controlling parasites.

Comparison of traditional copromicroscopy with image analysis devices for detection of gastrointestinal nematode infection in sheep

Sustainable parasite control practices are necessary to combat the negative effects of gastrointestinal nematodes on animal health and production while reducing the selection pressure for anthelmintic resistance. Parasite diagnostic tests can inform treatment decisions, the timing and effectiveness of treatment and enable livestock breeding programmes. In recent years new diagnostic methods have been developed, some incorporating machine learning (ML), to facilitate the detection and enumeration of parasite eggs. It is important to understand the technical characteristics and performance of such new methods compared to long standing and commonly utilised methods before they are widely implemented. The aim of the present study was to trial three new diagnostic tools relying on image analysis (FECPAKG2, Micron and OvaCyte) and to compare them to traditional manual devices (McMaster and Mini-FLOTAC). Faecal samples were obtained from 41 lambs naturally infected with gastrointestinal nematodes. Samples were mixed and separated into 2 aliquots for examination by each of the 5 methods: McMaster, Mini-FLOTAC, FECPAKG2, Micron and OvaCyte. The techniques were performed according to their respective standard protocols and results were collected by trained staff (McMaster and Mini-FLOTAC) or by the device (FECPAKG2, Micron and OvaCyte). Regarding strongyle worm egg count, McMaster values varied from 0 to 9,000 eggs per gram (EPG). When comparing replicate aliquots, both the Mini-FLOTAC and Micron methods displayed similar repeatability to McMaster. However, we found FECPAKG2 and OvaCyte significantly less precise than McMaster. When comparing parasite egg enumeration, significant positive linear correlations were established between McMaster and all other methods. No difference was observed in EPG between McMaster and Mini-FLOTAC or FECPAKG2; however, Micron and OvaCyte returned significantly higher and lower EPG, respectively, compared to McMaster. The number of eggs ascribed to other parasite species was not sufficient for performing a robust statistical comparison between all methods. However, it was noted that FECPAKG2 generally did not detect Strongyloides papillosus eggs, despite these being detected by other methods. In addition, Moniezia spp and Trichuris spp eggs were detected by OvaCyte and Mini-FLOTAC, respectively, but not by other methods. The observed variation between traditional and new methods for parasite diagnostics highlights the need for continued training and enhancing of ML models used and the importance of developing clear guidelines for validation of newly developed methods.

Anthelmintic screening of Bangladeshi medicinal plants and related phytochemicals using in vitro and in silico methods: An ethnobotanical perspective

ETHNOPHARMACOLOGICAL RELEVANCE

Infections caused by parasitic worms or helminth continue to pose a great burden on human and animal health, particularly in underdeveloped tropical and subtropical countries where they are endemic. Current anthelmintic drugs present serious limitations and the emergence of drug resistance has made it increasingly challenging to combat such infections (helminthiases). In Bangladesh, medicinal plants are often used by indigenous communities for the treatment of helminthiases. Knowledge on such plants along with screening for their anthelmintic activity has the potential to lead to the discovery of phytochemicals that could serve as novel molecular scaffolds for the development of new anthelminthic drugs.

AIM OF THE STUDY

The purpose of this study was i) to conduct an ethnobotanical survey to gather data on Bangladeshi medicinal plants used in the treatment of helminthiases, ii) to test plants with the highest use values for their in vitro anthelmintic activity, and iii) to carry out in silico screening on phytochemicals present in the most active plant extract to investigate their ability to disrupt β-tubulin function in helminths.

METHODS

The ethnobotanical survey was conducted across three sub-districts of Bangladesh, namely Mathbaria, Phultala and Khan Jahan Ali. The in vitro screening for anthelmintic activity was performed in a motility test using adult Haemonchus contortus worms. Virtual screening using PyRx was performed on the phytochemicals reported from the most active plant, exploring their interactions with the colchicine binding site of the β-tubulin protein target (PDB ID: 1SA0).

RESULTS

The survey respondents reported a total of 32 plants for treating helminthiases. Based on their use values, the most popular choices were Ananas comosus (L.) Merr., Azadirachta indica A.Juss., Carica papaya L., Citrus maxima (Burm.) Merr., Curcuma longa L., Momordica charantia L., Nigella sativa L. and Syzygium cumini (L.) Skeels. In vitro anthelmintic testing revealed that A. indica leaves and bark had the highest activity with LC50 values of 16 mg/mL in both cases. Other plant extracts also exhibited good anthelmintic activity with LC50 values ranging from 16 to 52 mg/mL, while the value for albendazole (positive control) was 8.39 mg/mL. The limonoids nimbolide and 28-deoxonimbolide showed a binding affinity of -8.9 kcal/mol, and satisfied all drug-likeness parameters. The control ligand N-deacetyl-N-(2-mercaptoacetyl)colchicine had a binding affinity of -6.9 kcal/mol.

CONCLUSION

Further in silico and in vitro studies are warranted on the identified limonoids to confirm the potential of these derivatives as novel drug templates for helminthiases. The current study supports the need for an ethnobotanical survey-based approach to discover novel drug templates for helminthiases.

Ascaridia galli, a common nematode in semiscavenging indigenous chickens in Bangladesh: epidemiology, genetic diversity, pathobiology, ex vivo culture, and anthelmintic efficacy

Ascaridia galli is the most common nematode in chickens. Ascaridia galli is highly prevalent in chickens reared in scavenging or semiscavenging systems. Here, we studied the epidemiology, pathology, genetic diversity, ex vivo culture protocol and anthelmintic sensitivity of A. galli prevalent in indigenous chickens in Bangladesh. Through morphological study and molecular analyses, the isolated worms were confirmed as A. galli. Of the chickens examined, 45.6% (178 out of 390) were found infected. The male and young chickens were significantly (P < 0.05) more prone to A. galli infection. Prevalence of the infection was significantly (P < 0.05) lower in the summer season. In heavy infections, A. galli blocked the small intestine. Marked inflammation, increased mucus production and petechial hemorrhages were evident in the small intestine, particularly in the duodenum. Also, there were desquamation and adhesion of the mucosal villi; degeneration, necrosis of the epithelial cells and goblet cell hyperplasia. The mucosal layer was infiltrated mainly with eosinophils and heterophils. We developed a hen egg white-based long-term ex vivo culture protocol which supported the survival and reproduction of A. galli for more than a week. Levamisole (LEV) and ivermectin (IVM) efficiently killed A. galli. However, albendazole (ABZ), mebendazole (MBZ), and piperazine (PPZ) did not kill the worms even at 120 μg/mL and 1mg/mL concentrations, respectively. Taken together, our results suggest that A. galli is highly prevalent in semiscavenging chickens in Bangladesh. Ascaridia galli can be easily maintained ex vivo in egg white supplemented M199 medium. LEV and IVM, but not ABZ, MBZ and PPZ, can be used for treating and controlling A. galli infections in chickens.

Understanding anthelmintic resistance in livestock using "omics" approaches

Widespread and improper use of various anthelmintics, genetic, and epidemiological factors has resulted in anthelmintic-resistant (AR) helminth populations in livestock. This is currently quite common globally in different livestock animals including sheep, goats, and cattle to gastrointestinal nematode (GIN) infections. Therefore, the mechanisms underlying AR in parasitic worm species have been the subject of ample research to tackle this challenge. Current and emerging technologies in the disciplines of genomics, transcriptomics, metabolomics, and proteomics in livestock species have advanced the understanding of the intricate molecular AR mechanisms in many major parasites. The technologies have improved the identification of possible biomarkers of resistant parasites, the ability to find actual causative genes, regulatory networks, and pathways of parasites governing the AR development including the dynamics of helminth infection and host-parasite infections. In this review, various "omics"-driven technologies including genome scan, candidate gene, quantitative trait loci, transcriptomic, proteomic, and metabolomic approaches have been described to understand AR of parasites of veterinary importance. Also, challenges and future prospects of these "omics" approaches are also discussed.

Ascaridia galli infection in chicken: Pathobiology and immunological orchestra

BACKGROUND

Ascaridia galli is the largest gut-dwelling helminth of chickens, which confers adverse effects on meat and egg production; thus, on the animal protein supply and the economy. Both adult and immature parasites affect gut health, but larval stages play a major role in pathology.

AIMS

Here, we present immunology and pathology of A. galli in chickens.

MATERIALS AND METHODS

Literatures were surveyed through online platforms such as PubMed, Google Scholar and Researchgate.

RESULTS

The larvae cause excessive mucus production, damage to the intestinal gland, hemorrhage, anemia, diarrhea, and malnutrition. The adult worms can cause death by intestinal obstruction and intussusception. Although both cellular and humoral immunity are involved in fighting against ascariasis, the role of naturally acquired immunity is poorly defined. In cellular immunity, Th-2 cytokines (IL-4, IL-5, IL-9, and IL-13), goblet cells (mucin), gut-associated lymphoid tissues, CD8α+ intraepithelial cells, TCRγδ + T cells, and TGF-β4 form a protective band. Type 2 immunity provides protection by forming a network of endogenous damage-associated molecular patterns, chitin, and parasitic antigens. Among antibodies, IgY is the most prominent in chickens and provides temporary humoral protection. During parasitic infection, infiltration of various immune cells is evident, especially in the intestinal epithelium, lamina propria, and crypts of the duodenum and jejunum. In chickens older than 12 weeks, gradual reduction of worm burden is more successful than the younger birds. Female chickens exert a short-lived but higher level of protection by passing IgY to chicks in the form of egg yolk antibodies. In laying conditions, immunity differs between breeds. This review provides an overview of the silent but inevitable pathological changes induced by A. galli and the interaction of host immunity with the parasite.

Effect of Ivermectin on the Expression of P-Glycoprotein in Third-Stage Larvae of Haemonchus contortus Isolated from China

Haemonchus contortus poses a severe hazard to the healthy development of the sheep industry and threatens the welfare of sheep. Ivermectin is the primary anthelmintic used for the prevention and treatment of H. contortus parasitism. However, the widespread and uncontrolled application of ivermectin has resulted in the development and spread of resistant strains of H. contortus. P-glycoprotein (P-gp) plays important roles in the pharmacology and toxicology of ivermectin, and changes in P-gp expression levels can be used to analyze the resistance of H. contortus to ivermectin. This study aimed to analyze the effects of ivermectin on P-gp expression in H. contortus L3 larvae isolated from China and to evaluate whether changes in P-gp expression levels can be used to analyze resistant H. contortus strains. In the absence of drug treatment, the ivermectin-resistant strains isolated in China showed increased expression of P-gp11 (p < 0.01) compared with sensitive strains from elsewhere, whereas the expressions of P-gp2 and P-gp9.1 were downregulated (p < 0.01). When the same strain was compared before and after drug treatment, obvious differences in expression were observed between the different strains. Ivermectin-induced P-gp expression was found to be very complex among the L3 larvae of different strains. In addition, it was confirmed that using P-gp to determine ivermectin resistance in H. contortus strains from different geographic environments can yield different results.

Essential oils and essential oil compounds in animal production as antimicrobials and anthelmintics: an updated review

Several countries have shown an increased prevalence of drug resistance in animal production due to the indiscriminate use of antibiotics and antiparasitics in human and veterinary medicine. This article aims to review existing methods using naturally occurring essential oils (EOs) and their isolated compounds (EOCs) as alternatives to antimicrobials and antiparasitic compounds in animal production and, consequently, to avoid resistance. The most-reported mechanism of action of EOs and EOCs was cell membrane damage, which leads to the leakage of cytoplasmic content, increased membrane permeability, inhibition of metabolic and genetic pathways, morphologic changes, antibiofilm effects, and damage to the genetic material of infections. In parasites, anticoccidial effects, reduced motility, growth inhibition, and morphologic changes have been reported. Although these compounds regularly show a similar effect to those promoted by traditional drugs, the elucidation of their mechanisms of action is still scarce. The use of EOs and EOCs can also positively influence crucial parameters in animal production, such as body weight gain, feed conversion rate, and cholesterol reduction, which also positively impact meat quality. The application of EOs and EOCs is enhanced by their association with other natural compounds or even by the association with synthetic chemicals, which has been found to cause synergism in their antimicrobial effect. By reducing the effective therapeutical/prophylactic dose, the chances of off-flavors – the most common issue in EO and EOC application – is greatly mitigated. However, there is very little work on the combination of EOs and EOCs in large in vivo studies. In addition, research must apply the correct methodology to properly understand the observed effects; for example, the use of only high concentrations may mask potential results obtained at lower dosages. Such corrections will also allow the elucidation of finer mechanisms and promote better biotechnologic use of EOs and EOCs. This manuscript presents several information gaps to be filled before the use of EOs and EOCs are fully applicable in animal production.

Efficacy of clinically used anthelmintics against toxocariasis of buffalo calves in Bangladesh

Toxocariasis is a paramount parasitic disease having > 50% prevalence among newborn buffalo calves in Bangladesh. The objective of this study was to compare the efficacy of clinically used anthelmintics and their subsequent effect on the haematological parameters and body weight in buffalo calves in commercial buffalo farms in coastal region. Thirty-two buffalo calves below 3 months of age with clinical Toxocara infection had been selected and treated with albendazole (ABZ), levamisole (LVM) and ivermectin (IVM). The EPG counts, hematological parameters and initial body weight of buffalo calves were recorded on the day of anthelmintic treatment (day 0). Fecal samples were collected on day 14 and 28 including hematological parameters and body weight were recorded on day 28 post-treatment. The efficacy (%) of anthelmintics were estimated by fecal egg count reduction test (FECRT). The parameters like Hb, PCV, ESR, TEC, TLC were analyzed from the blood samples. The FECRT revealed 96.83% efficacy for IVM followed by 94.23% and 85.84% for LVM and ABZ, respectively. Anthelmintic treated calves showed significant (p < 0.01) increase in Hb, PCV, TEC and body weight, and decrease in ESR and TLC as a result of worm expulsion from buffalo calves after 28 days of post-treatment. Among the tested anthelmintics, IVM was found to be more effective against toxocariasis in buffalo calves. This is a novel information on anthelmintics efficacy in buffalo calves in Bangladesh. Details study is recommended on the efficacy of anthelmintics in different buffalo management systems by in vitro egg hatch assay (EHA) test.

Microbial community in resistant and susceptible Churra sheep infected by Teladorsagia circumcincta

Gastrointestinal nematodes (GIN) are a major threat to health and welfare in small ruminants worldwide. Teladorsagia circumcincta is a nematode that inhabits the abomasum of sheep, especially in temperate regions, causing important economic losses. Given that T. circumcincta and microbiome share the same niche, interactions between them and the host are expected. Although it is known that within a sheep breed there are animals that are more resistant than others to infection by GIN, it is not known if the microbiome influences the phenotype of these animals. Under this condition, 12 sheep were classified according to their cumulative faecal egg count (cFEC) at the end of a first experimental infection, 6 as resistant group (RG) and 6 as susceptible group (SG) to T. circumcincta infection. Then, all sheep were experimentally infected with 70,000 L3 of T. circumcincta and at day 7 days post-infection were euthanized. At necropsy, gastric mucosa and gastric content from abomasum were collected to extract bacterial DNA and sequence V3-V4 region from 16S rRNA gene using Ilumina technology. After bioanalysis performed, results showed that α-diversity and β-diversity remained similar in both groups. However, resistant phenotype sheep showed a higher number of bacteria butyrate-fermenting species as Clostridium sensu stricto 1 (abundance in RG: 1.29% and in SG: 0.069%; p = 0.05), and Turicibacter (abundance in RG: 0.31% and in SG: 0.027%; p = 0.07) in gastric content but also Serratia spp in gastric mucosa (abundance in RG: 0.12% and in SG: 0.041%; p = 0.07). A trend towards a significant negative correlation between cFEC and Clostridium sensu stricto 1 abundance in gastric content was detected (r = - 0.537; p = 0.08). These data suggest that microbiome composition could be another factor associated with the development of the resistant phenotype modifying the interaction with the host and the in last instance affecting the individual risk of infection.

Efficacy of flukicides on Fasciola gigantica, a food-borne zoonotic helminth affecting livestock in Bangladesh

Fasciola gigantica, the causative agent of tropical fasciolosis, is a food-borne zoonotic trematode that affects around 80% livestock of Bangladesh. Triclabendazole (TCBZ), nitroxynil (NTON) and oxyclozanide (OCZN) are frequently used against fascioliasis; however, the current status of potency of these flukicides was unknown. In this study, in vitro efficacy of TCBZ, NTON and OCZN at various concentrations on F. gigantica has been evaluated by relative motility (RM), morphological distortions of apical cone through an inverted microscope, architectural and ultra-structural changes through histopathological and scanning electron microscopy (SEM). It is observed that TCBZ, NTON and OCZN at higher concentrations significantly (P < 0.05) reduced RM of the flukes compared to untreated control. NTON at 150 μg mL−1 was the most potent to reduce the motility within 4 h whereas TCBZ and OCZN were much delayed. Histopathological changes showed swollen, extensive cracking, numerous vacuoles and splitting of the tegument surrounding the spines; spine dislodged from its socket in treated flukes compared to untreated worms. Histopathological changes were more conspicuous at higher doses of TCBZ, NTON and OCZN. SEM has shown the disruption of the apical cone, apart from swelling of the tegument on the ventral surface corrugation and disruption of the ventral apical cone. All these changes indicate that NTON is the most potent in killing flukes in vitro among the tested flukicides and suggest the presence of TCBZ-resistant fluke populations in Bangladesh. It is imperative to explore the in vivo effects of these flukicides and subsequently their molecular mechanisms.

In vitro ovicidal activity of Brongniartia montalvoana against small ruminant gastrointestinal nematodes

Several plants of the Fabaceae family have been assessed regarding their high nutritional value and anthelmintic properties. The ovicidal effect of the hydroalcoholic extract (Bm-HAE) and subfractions from the aerial parts of Brongniartia montalvoana (Fabaceae) against a mixed strain of gastrointestinal nematodes (GIN) (Haemonchus spp., Trichostrongylus spp. and Oesophagostomum spp.) resistant to albendazole sulfoxide, ivermectin and levamisole was evaluated by the egg hatch test (EHT). The Bm-HAE was subjected to liquid-liquid chemical separation with ethyl acetate giving two fractions, an aqueous (Bm-Aq) and an organic (Bm-EtOAct). The purification of the bioactive fraction (Bm-EtOAct) through chromatographic separation resulted in four bioactive subfractions (BmR6, BmR7, BmR8 and BmR10). The treatments were designed as follows: Bm-HAE at 800, 1,500, 3,000 and 6,000 μg/mL, and Bm-Aq, Bm-EtOAct and subfractions (BmR6, BmR7, BmR8 and BmR10) at 100, 200, 400 and 800 μg/mL. Two properly negative controls (distilled water and 2% methanol) and thiabendazole (100 μg/mL) as a positive control were used for each bioassay. The chemical identification of the extract, fractions and subfractions was performed through chromatographic processes like open column chromatography, thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC-PDA). Additionally, the GIN eggs exposed to the bioactive compounds were observed through confocal laser scanning microscopy (CLSM). The Bm-HAE showed 99.5% egg hatching inhibition (EHI) at 6,000 μg/mL with a lethal concentration (LC₅₀) of 1110 μg/mL. The Bm-EtOAc fraction displayed 99.1% EHI at 800 μg/mL with LC₅₀ = 180 μg/mL. The ovicidal activity of the four subfractions was similar at 800 μg/mL: BmR6 (92% EHI); BmR7 (100% EHI); BmR8 (97.8%); and BmR10 (99.1%). The HPLC-PDA analysis of the bioactive subfractions allowed identification of p-coumaric acid, ferulic acid and coumarin derivatives as major compounds. The CLSM analysis allowed observation of morphological alterations in unhatched larvae caused by bioactive compounds present in the Bm-EtOAc and BmR10. In addition, the flavonoids eriodyctiol, luteolin and cynaroside were described for the first time for B. montalvoana.

Investigating the benefits of targeted selective treatment according to average daily weight gain against gastrointestinal nematodes in Morada Nova lambs

The objective of this study was to evaluate a method of targeted selective treatment (TST) of Morada Nova lambs, based on the average daily weight gain (DWG). For this, 114 lambs in the rainy and 102 in the dry season were randomized into three treatments: control (CT), routine (RT, treated every 42 days), and targeted selective (TST, treated according to DWG). Packed cell volume (PCV) and eggs per gram of feces (EPG) tests were performed. The anthelmintic resistance of parasites was assessed by the EPG count reduction test (FECRT), RESISTA-Test^©, and molecular test. For CT, RT, and TST groups, the following results were obtained: mean EPG values were 4665.1, 3063.5, and 3462.1 in the rainy season and 4475.1, 1341.7, and 2863.4 in the dry season, respectively; mean PCV values were 32.1, 33.4, and 32.3% in the rainy season and 33.9, 36.0, and 35.1% in the dry season; mean DWG readings were 0.087, 0.101, and 0.094 kg in the rainy season and 0.102, 0.113, and 0.112 kg in the dry season; efficacies of levamisole in FECRT were 66.4, 24.1, and 76.4% in the rainy and 90.7, 12.4, and 64.8% in the dry season, respectively; in the RESISTA-Test^©, the LC₅₀ values were 0.482, 1.926, and 0.117 µg.mL^-1 in the rainy and 0.437, 0.851, and 0.045 µg.mL^-1 in the dry season, respectively; the frequencies of the homozygous-resistant genotype were 57.1, 71.4, and 40.0% in the rainy and 47.8, 55.9, and 41.9% in the dry season. In conclusion, TST reduced the development of resistance through refugia maintenance, without productive losses, contributing to the sustainability of sheep breeding.

Positivity Rate Investigation and Anthelmintic Resistance Analysis of Gastrointestinal Nematodes in Sheep and Cattle in Ordos, China

Simple Summary

In order to understand the positivity rates of gastrointestinal nematodes in cattle and sheep in Ordos, and the effects of different pasture types on the distribution of gastrointestinal nematodes, we conducted an epidemiological investigation and analysis in four banner districts of Ordos. The results showed that the positive rates of sheep and cattle were 38.84% and 4.48%, respectively. The anthelmintic resistance analysis revealed that the nematode population in the area was severely resistant to ivermectin and albendazole, and resistance to levamisole, nitroxynil and closantel was suspected.

Abstract

Gastrointestinal nematodes (GINs), such as Trichostrongylidae, are important pathogens in small ruminants, causing significant losses in these livestock species. Despite their veterinary importance, GINs have not been studied in certain regions of the world. Therefore, much of their epidemiology and economic impact on production remain unknown. In the present study, a systematic epidemiological survey based on the modified McMaster technique was conducted to investigate the type and infection of GINs in sheep and cattle. In 9622 fecal samples from 491 sampling sites in the four main banner districts of Ordos, the prevalence of GIN infection was found to be 38.84% and 4.48% in sheep and cattle, respectively. At the same time, the effects of four pasture types on the distribution of GINs were analyzed. This study also found severe resistance to ivermectin and albendazole in GINs and suspected anthelmintic resistance in nitroxynil, levamisole and closantel. We report the type and infection of GINs in Ordos, with the aim to help the prevention and control of GINs. Based on the results of the questionnaire survey and GIN resistance test, we found several reasons for the anthelmintic resistance of GINs, consequently providing new ideas for controlling the occurrence of anthelmintic resistance.

In vitro nematocidal activity of Punica granatum L. against gastrointestinal helminths in goats

The objective of this study was to evaluate the in vitro ovicidal activity, phytochemistry, and toxicity of a saline extract obtained from peel of Punica granatum L fruits. The ovicidal activity was evaluated by the hatching inhibition of eggs recovered from fecal samples of naturally infected goats; the phytochemical analysis was carried out using the fruit peel; and the toxicity was tested on Artemia salina, using saline extract. The results showed that the ovicidal effect of the tested extract was 99% (25 mg mL^-1), 99% (12.5 mg mL^-1), 98% (6.25 mg mL^-1), and 95% (3.12 mg mL^-1), higher than that of the control drug, thiabendazole (83%). The phytochemical analysis showed presence of phenols, anthraquinones, and condensed and hydrolysable tannins in the fruit extract. The toxicity test of the extract of P. granatum showed an LC50 of 6.19 mg mL^-1, which indicates a safe use for a concentration of 3.12 mg mL^-1, since it was the tested concentration that was below the reliable LC50. The saline extract from peels of P. granatum has ovicidal activity, important secondary metabolites, and absence of toxicity at the lowest concentration tested. However, in vivo tests in experimental models are recommended before performing experiments in ruminants.

Helminth Infections in Cattle and Goats in Kanchanaburi, Thailand, with Focus on Strongyle Nematode Infections

Gastrointestinal helminths are major enteric parasites affecting the health of important livestock ruminants, such as cattle and goats. It is important to routinely survey these animals for helminth infections to allow effective management and control programs to be implemented. A cross-sectional helminth survey carried out in Kanchanaburi Province, Thailand, revealed the infection rate of gastrointestinal helminths in cattle (n = 157) and goats (n = 117) to be 35.7% and 88%, respectively, by microscopic fecal examination, and a 100% herd prevalence was observed in goats. Eggs of strongyle nematodes, Strongyloides spp., Trichuris spp., Capillaria spp., Paramphistomum spp., and Moniezia spp. were detected, with a relatively high rate of strongyle nematode infection in both cattle (28.7%) and goats (86.3%). Mixed infections were observed in 14.3% and 35.9% of egg-positive samples from cattle and goats, respectively. Risk factor analysis showed that dairy cattle were 5.1 times more likely to be infected with strongyles than meat cattle. In contrast, meat goats were 9.3 times more likely to be infected with strongyles than dairy goats. The inverse findings in cattle and goats are discussed. Female gender was associated with a higher risk of strongyle infection in goats. DNA sequencing and in-house semi-nested PCR with primers specific to a region in the internal transcribed spacer 2 (ITS2) were successfully used to identify strongyle genera in randomly selected egg-positive cattle (n = 24) and goat (n = 24) samples. Four strongyle genera, i.e., Cooperia spp., Haemonchus spp., Oesophagostomum spp., and Trichostrongylus spp. were identified by DNA sequencing. By semi-nested PCR, Cooperia spp. were detected as a major parasite of cattle (70.8%), whereas Haemonchus spp. were abundant in goats (100%). The majority of samples from cattle (58.3%) and goats (95.8%) were found to coinfect with at least two strongyle genera, suggesting that coinfection with multiple strongyle genera was more common than single infection in these animals.

Prevalence of anthelmintic resistance of gastrointestinal nematodes in Polish goat herds assessed by the larval development test

Background

Helminthic infections, in particular those caused by gastrointestinal nematodes (GIN), are found worldwide and are among the most economically important diseases of goats. Anthelmintic resistance (AR) in GIN of goats is currently present worldwide, and single- or multidrug resistant species are widespread. The aim of this study was to determine the prevalence of AR to benzimidazoles (BZ), macrocyclic lactones (ML) and imidazothiazoles represented by levamisole (LEV) in the Polish goat herds by using an in vitro larval development test, which is useful especially in large-scale epidemiological surveys.

Results

This cross-sectional study was conducted from September 2018 to June 2019 and enrolled 42 dairy goat herds scattered over the entire country. The most commonly used anthelmintic class in goat herds in Poland were BZ (92%), followed by ML (85%) and LEV (13%). BZ-resistant GIN populations were found in 37 herds (88%, CI 95%: 75 to 95%), ML-resistant GIN populations in 40 herds (95%, CI 95, 84 to 99%), and LEV-resistant GIN populations in 5 herds (12%, CI 95%: 5 to 25%). Multidrug resistance involving all three anthelmintic classes was found in 5 herds (12%, CI 95, 5 to 25%). Based on the morphological features of stage 3 larvae the main resistant GIN turned out to be Haemonchus contortus and Trichostrongylus spp. The use of BZ and frequency of anthelmintic treatments were significantly related to the presence of AR to BZ in Polish goat herds.

Conclusions

This cross-sectional study demonstrates the existence of AR to BZ, ML and LEV on Polish goat farms. Resistance to BZ and ML is widespread, while AR to LEV is currently at a low level. A considerable proportion of herds harbours multidrug resistant GIN, which requires further consideration. An effective anthelmintic treatment strategy, reasonable preventive measures and better understanding of the resistance-related management practices by farmers and veterinarians may delay further development of AR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-020-02721-9.