scholarly journals Susceptible trichostrongyloid species mask presence of benzimidazole-resistant Haemonchus contortus in cattle

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Khalid M. Mohammedsalih ◽  
Jürgen Krücken ◽  
Ahmed Bashar ◽  
Fathel-Rahman Juma ◽  
Abdalhakaim A. H. Abdalmalaik ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Epidemiological Data ◽  
Nematode Species ◽  
Parasitic Nematodes ◽  
Molecular Approaches ◽  
Tubulin Genes ◽  
Faecal Egg Count ◽  
Third Stage ◽  
Before And After ◽  
Β Tubulin

Abstract Background Benzimidazole (BZ) anthelmintics are widely used to control infections with parasitic nematodes, but BZ resistance is an emerging threat among several nematode species infecting humans and animals. In Sudan, BZ-resistant Haemonchus contortus populations were recently reported in goats in South Darfur State. The objective of this study was to collect data regarding the situation of BZ resistance in cattle parasitic nematodes in South Darfur using phenotypic and molecular approaches, besides providing some epidemiological data on nematodes in cattle. Methods The faecal egg count reduction test and the egg hatch test (EHT) were used to evaluate benzimidazole efficacy in cattle nematodes in five South Darfur study areas: Beleil, Kass, Nyala, Rehed Al-Birdi and Tulus. Genomic DNA was extracted from pools of third-stage larvae (L3) (n = 40) during trials, before and after treatment, and pools of adult male Haemonchus spp. (n = 18) from abattoirs. The polymorphisms F167Y, E198A and F200Y in isotype 1 β-tubulin genes of H. contortus and H. placei were analysed using Sanger and pyrosequencing. Results Prevalence of gastro-intestinal helminths in cattle was 71% (313/443). Reduced albendazole faecal egg count reduction efficacy was detected in three study areas: Nyala (93.7%), Rehed Al-Birdi (89.7%) and Tulus (88.2%). In the EHT, EC50 values of these study areas ranged between 0.032 and 0.037 µg/ml thiabendazole. Genus-specific PCRs detected the genera Haemonchus, Trichostrongylus and Cooperia in L3 samples collected after albendazole treatment. Sanger sequencing followed by pyrosequencing assays did not detect elevated frequencies of known BZ resistance-associated alleles in codon F167Y, E198A and F200Y in isotype 1 β-tubulin gene of H. placei (≤ 11.38%). However, polymorphisms were detected in H. contortus and in samples with mixed infections with H. contortus and H. placei at codon 198, including E198L (16/58), E198V (2/58) and potentially E198Stop (1/58). All pooled L3 samples post-albendazole treatment (n = 13) were identified as H. contortus with an E198L substitution at codon 198. Conclusions To the knowledge of the authors, this is the first report of reduced albendazole efficacy in cattle in Sudan and is the first study describing an E198L substitution in phenotypically BZ-resistant nematodes collected from cattle.

scholarly journals Extreme allelic heterogeneity at a Caenorhabditis elegans beta-tubulin locus explains natural resistance to benzimidazoles

2018 ◽  
Author(s):  
Steffen R. Hahnel ◽  
Stefan Zdraljevic ◽  
Briana C. Rodriguez ◽  
Yuehui Zhao ◽  
Patrick T. McGrath ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nematode Species ◽  
Natural Resistance ◽  
Parasitic Nematodes ◽  
Loss Of Function ◽  
Tubulin Gene ◽  
Free Living ◽  
C Elegans ◽  
Tubulin Genes ◽  
Β Tubulin

AbstractBenzimidazoles (BZ) are essential components of the limited chemotherapeutic arsenal available to control the global burden of parasitic nematodes. The emerging threat of BZ resistance among nearly all nematode species necessitates the development of novel strategies to identify genetic and molecular mechanisms underlying this resistance. All detection of parasitic helminth resistance to BZ is focused on the genotyping of three variant sites in the orthologs of the β-tubulin gene found to confer resistance in the free-living nematode Caenorhabditis elegans. Because of the limitations of laboratory and field experiments in parasitic nematodes, it is difficult to look beyond these three sites, and additional BZ resistance is observed in the field. Here, we took an unbiased genome-wide mapping approach in the free-living nematode species C. elegans to identify the genetic underpinnings of natural resistance to the commonly used BZ, albendazole (ABZ). We found a wide range of natural variation in ABZ resistance in natural C. elegans populations. In agreement with known mechanisms of BZ resistance in parasites, we find that a majority of the variation in ABZ resistance among wild C. elegans strains is caused by variation in the β-tubulin gene ben-1. This result shows empirically that resistance to ABZ naturally exists and segregates within the C. elegans population, suggesting that selection in natural niches could enrich for resistant alleles. We identified 25 distinct ben-1 alleles that are segregating at low frequencies within the C. elegans population, including many novel molecular variants. Population genetic analyses indicate that ben-1 variation arose multiple times during the evolutionary history of C. elegans and provide evidence that these alleles likely occurred recently because of local selective pressures. Additionally, we find purifying selection at all five β-tubulin genes, despite predicted loss-of-function resistants variants in ben-1, indicating that BZ resistance in natural niches is a stronger selective pressure than loss of one β-tubulin gene. Furthermore, we use genome-editing to show that the most common parasitic nematode β-tubulin allele that confers BZ resistance, F200Y, confers resistance in C. elegans. Importantly, we identified a novel genomic region that is correlated with ABZ resistance in the C. elegans population but independent of ben-1 and the other β-tubulin loci, suggesting that there are multiple mechanisms underlying BZ resistance. Taken together, our results establish a population-level resource of nematode natural diversity as an important model for the study of mechanisms that give rise to BZ resistance.Author summaryNematode parasites have a tremendous impact on human health with almost two billion people infected worldwide. The control of nematode infections relies mainly on the efficacy of a limited repertoire of anthelmintic compounds, including the benzimidazoles (BZ). Already a significant problem in veterinary medicine, increasing evidence exists for the development of BZ resistance in nematodes that infect humans. Laboratory screens and field surveys identified β-tubulin genes as major determinants of BZ resistance in nematodes but detailed population-wide genetic analyses of resistance mechanisms are only just beginning. Therefore, we took advantage of the free-living model organism Caenorhabditis elegans to study the genetic basis of resistance to the commonly used BZ, albendazole (ABZ) in a natural nematode population. Performing genome-wide association mappings, we were able to identify extreme heterogeneity in the β-tubulin gene ben-1 as a major determinant of ABZ resistance. Moreover, our study provided new insights into the effects of missense and loss-of-function alleles at this locus, and how anthelmintic resistance could have developed within a natural nematode population.

Effects of four tanniferous plant extracts on thein vitroexsheathment of third-stage larvae of parasitic nematodes

Parasitology ◽  
2006 ◽  
Vol 132 (4) ◽  
pp. 545-554 ◽  
Author(s):  
D. BAHUAUD ◽  
C. MARTINEZ-ORTIZ DE MONTELLANO ◽  
S. CHAUVEAU ◽  
F. PREVOT ◽  
F. TORRES-ACOSTA ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Plant Extracts ◽  
Castanea Sativa ◽  
Nematode Species ◽  
Parasitic Nematodes ◽  
Rye Grass ◽  
Pine Tree ◽  
Third Stage

The anthelmintic properties of tanniferous plants and of their secondary metabolites represent one possible alternative to chemotherapy that is currently being explored as a means of achieving sustainable control of gastrointestinal nematodes in ruminants. Previousin vivoandin vitroresults suggest that tanniferous plants can have direct anti-parasitic effect against different stages of nematodes. However, the mode of action of the bioactive plant compounds remains obscure. The objectives of the current study were (1) to examine the hypothesis that extracts of tanniferous plants might interfere with the exsheathment of third-stage infective larvae (L3); (2) to assess the role of tannins in the process by examining the consequence of adding an inhibitor of tannins (polyethylene glycol: PEG) to extracts. The effects of 4 tanniferous plant extracts on exsheathment have been examined on L3 ofHaemonchus contortusandTrichostrongylus colubriformis. Artificial exsheathment was inducedin vitroby adding hypochloride solution to larval suspension. The evolution of exsheathment with time was measured by repeated observations at 10-min interval for 60 min. The selected plants were: genista (Sarothamnus scoparius), heather (Erica erigena), pine tree (Pinus sylvestris), and chestnut tree (Castanea sativa), with tannin contents ranging from 1·5 to 24·7% of DM. Extracts of a non-tanniferous plant (rye grass, tannin content: 0·3% of DM) were included in the assay as negative controls. The extracts were tested at the concentration of 600 μg/ml and the effects were compared to the rate of exsheathment of control larvae in PBS. No statistical differences in the pattern of exsheathment was observed after addition of rye grass or genista extracts for both nematode species and with heather extracts forT. colubriformis. In contrast, pine tree extracts on larvae of both species and heather extracts withH. contortusinduced a significant delay in exsheathment. Last, contact with chest nut extracts led to a total inhibition of the process for both nematodes. These results suggest that extracts of tanniferous plants might affect a key process in the very early stages of larval invasion of the host. In most cases, the addition of PEG led to a total or partial restoration towards control values. This suggests that tannins are largely involved in the inhibitory process. However, other secondary metabolites may also interfere with the process that would help to explain some of the differences in response observed between the two nematode species.

scholarly journals Complementary Approaches to Understand Anthelmintic Resistance Using Free-Living and Parasitic Nematodes

2020 ◽  
Author(s):  
Janneke Wit ◽  
Clayton Dilks ◽  
Erik Andersen
Keyword(s):  
Haemonchus Contortus ◽  
Parasitic Nematode ◽  
Anthelmintic Resistance ◽  
Nematode Species ◽  
The Other ◽  
Parasitic Nematodes ◽  
Mechanisms Of Resistance ◽  
Free Living ◽  
Sustained Efficacy ◽  
Modes Of Action

Anthelmintic drugs are the major line of defense against parasitic nematode infections, but the arsenal is limited and resistance threatens sustained efficacy of the available drugs. Discoveries of the modes of action of these drugs and mechanisms of resistance have predominantly come from studies of a related non-parasitic nematode species, Caenorhabditis elegans, and the parasitic nematode Haemonchus contortus. Here, we discuss how our understanding of anthelmintic resistance and modes of action came from the interplay of results from each of these species. We argue that this “cycle of discovery”, where results from one species inform the design of experiments in the other, can use the complementary strengths of both to understand anthelmintic modes of action and mechanisms of resistance.

scholarly journals Comparative anthelmintic efficacy of Arundo donax, Areca catechu, and Ferula assa-foetida against Haemonchus contortus

2021 ◽  
Vol 30 (2) ◽  
Author(s):  
Syed Nadeem Badar ◽  
Zafar Iqbal ◽  
Muhammad Sohail Sajid ◽  
Hafiz Muhammad Rizwan ◽  
Muhammad Shareef ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Haemonchus Contortus ◽  
Anthelmintic Activity ◽  
Parasitic Nematodes ◽  
Egg Hatch ◽  
Faecal Egg Count ◽  
Areca Catechu ◽  
Better Than

Abstract In the present study, anthelmintic activities of Arundo (A.) donax L., Areca (Ar.) catechu L., and Ferula (F.) assa-foetida L. were determined. Leaves of A. donax L., latex of F. assa-foetida L. and seeds of Ar. catechu L. in different solvent fractions were subjected to in vitro (egg hatch assay; EHA, and adult motility assay; AMA) and in vivo (faecal egg count reduction test; FECRT) tests of anthelmintic activity using Haemonchus contortus model. In the AMA, crude aqueous methanol extracts (CAME) and ethyl acetate fractions of F. assa-foetida at 10 hr post-treatment showed maximum mortality of H. contortus at 12.5-50 mg mL-1. In the EHA, CAME of F. assa-foetida was identified as a potent ovicide based on its low LC50 (16.9 µg mL-1), followed in order by Ar. catechu and A. donax. Results from the FECRT also showed the extract of F. assa-foetida L. to be more effective than those of Ar. catechu L. and A. donax L., against the gastrointestinal parasitic nematodes. Chloroform and ethyl acetate fractions showed better anthelmintic activities against the adult worms in vitro, while CAME of these plants were better than their crude powders in vivo. It is recommended to document and investigate indigenous knowledge of possible medicinal plants to plan scientific trials that may justify their endorsement.

The respiratory metabolism of parasitic nematodes

Parasitology ◽  
1948 ◽  
Vol 39 (1-2) ◽  
pp. 105-109 ◽  
Author(s):  
W. P. Rogers
Keyword(s):  
Haemonchus Contortus ◽  
Potassium Cyanide ◽  
The Other ◽  
Parasitic Nematodes ◽  
Ascaridia Galli ◽  
Reserve Material ◽  
Infective Larvae ◽  
Third Stage ◽  
Area Basis ◽  
Surface Area Basis

1. Qo2 values for Haemonchus contortus egs varied between − 9·7 and − 12·6 according to the degree of development of the embryos. The r.q. was in the region of 0·6.2. Young infective larvae of Nippostrongylus muris had a high Qo2 (−18·4), which fell as the larvae aged. Third stage Haemonchus contortus larvae gave similar results. The respiration was not affected by exsheathment.3. Adult parasites gave Qo2 values as follows: Ascaridia galli, − 2·5; Nematodirus spp., − 5·1; Nippostrongylus muris, − 6·8; Neoaplectana glaseri, − 12·6. When calculated on a surface area basis, Ascaridia galli had an oxygen uptake which was much higher than that of the other organisms.4. Qco2 values were small. The r.q. of infective larvae, which contain fat as reserve material, was about 0·72. The other forms which contained much glycogen as well as fat had r.q. values between 0·6 and 0·7. A. galli was an exception in that an r.q. of about 0·95 was obtained.5. Potassium cyanide inhibited respiration in all the forms examined.The author is indebted to Dr R. W. Glaser for supplying a strain of Neoaplectana glaseri.

Complementary Approaches to Understand Anthelmintic Resistance Using Free-Living and Parasitic Nematodes

2020 ◽  
Author(s):  
Janneke Wit ◽  
Clayton Dilks ◽  
Erik Andersen
Keyword(s):  
Haemonchus Contortus ◽  
Parasitic Nematode ◽  
Anthelmintic Resistance ◽  
Animal Health ◽  
Nematode Species ◽  
Parasitic Nematodes ◽  
Mechanisms Of Resistance ◽  
Free Living ◽  
Powerful Approach ◽  
Anthelmintic Drugs

Parasitic nematode infections impact human and animal health globally, especially in the developing world. Anthelmintic drugs are the major line of defense against these infections, but the arsenal is limited. Additionally, anthelmintic resistance is widespread in veterinary parasites and an emerging threat in human parasites. Discoveries of the mode of action of these drugs and mechanisms of resistance have predominantly come from studies of a related non-parasitic nematode species, Caenorhabditis elegans, and the parasitic nematode Haemonchus contortus. Here, we discuss recent progress understanding anthelmintic resistance using these two species and how that progress relates to laboratory and field-based studies of veterinary helminths. We present a powerful approach enabled by the strengths of both nematode species to understand mechanisms of resistance and modes of action of anthelmintic drugs.

scholarly journals The use of high resolution melting analysis of ITS-1 for rapid differentiation of parasitic nematodes Haemonchus contortus and Ashworthius sidemi

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lucie Skorpikova ◽  
Nikol Reslova ◽  
Jan Magdalek ◽  
Jaroslav Vadlejch ◽  
Martin Kasny
Keyword(s):  
High Resolution ◽  
Haemonchus Contortus ◽  
High Resolution Melting ◽  
Nematode Species ◽  
Gastrointestinal Nematodes ◽  
High Resolution Melting Analysis ◽  
Parasitic Nematodes ◽  
Correct Identification ◽  
Ashworthius Sidemi ◽  
Melting Analysis

Abstract Among gastrointestinal nematodes, haematophagous strongylids Haemonchus contortus and Ashworthius sidemi belong to the most pathogenic parasites of both domestic and wild ruminants. Correct identification of parasitic taxa is of crucial importance in many areas of parasite research, including monitoring of occurrence, epidemiological studies, or testing of effectiveness of therapy. In this study, we identified H. contortus and A. sidemi in a broad range of ruminant hosts that occur in the Czech Republic using morphological/morphometric and molecular approaches. As an advanced molecular method, we employed qPCR followed by High Resolution Melting analysis, specifically targeting the internal transcribed spacer 1 (ITS-1) sequence to distinguish the two nematode species. We demonstrate that High Resolution Melting curves allow for taxonomic affiliation, making it a convenient, rapid, and reliable identification tool.

scholarly journals High levels of third-stage larvae (L3) overwinter survival for multiple cattle gastrointestinal nematode species on western Canadian pastures as revealed by ITS2 rDNA metabarcoding

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Tong Wang ◽  
Russell W. Avramenko ◽  
Elizabeth M. Redman ◽  
Janneke Wit ◽  
John S. Gilleard ◽  
...  
Keyword(s):  
Control Strategies ◽  
Gastrointestinal Nematode ◽  
Nematode Species ◽  
Effective Control ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Third Stage ◽  
Before And After ◽  
Southern Central ◽  
Solar Powered

Abstract Background The ability of infective larvae of cattle gastrointestinal nematode (GIN) species to overwinter on pastures in northerly climatic zones with very cold dry winters is poorly understood. This is an important knowledge gap with critical implications for parasite risk assessment and control. Methods Infective third-stage larvae (L3) were quantified in samples of fecal pats, together with adjacent grass and soil, before and after winter on three farms in southern, central and northern Alberta. Nemabiome ITS2 metabarcoding was then performed on the harvested L3 populations to determine the species composition. Finally, parasite-free tracer calves were used to investigate if the L3 surviving the winter could infect calves and develop to adult worms in spring. Results Farm level monitoring, using solar powered weather stations, revealed that ground temperatures were consistently higher, and less variable, than the air temperatures; minimum winter air and ground temperatures were − 32.5 °C and − 24.7 °C respectively. In spite of the extremely low minimum temperatures reached, L3 were recovered from fecal pats and grass before and after winter with only a 38% and 61% overall reduction over the winter, respectively. Nemabiome ITS2 metabarcoding assay revealed that the proportion of L3 surviving the winter was high for both Cooperia oncophora and Ostertagia ostertagi although survival of the former species was statistically significantly higher than the latter. Nematodirus helvetinaus and Trichostrongylus axei could be detected after winter whereas Haemonchus placei L3 could not overwinter at all. Adult C. oncophora, O. ostertagi and N. helvetianus could be recovered from tracer calves grazing after the winter. Conclusions The largest proportion of L3 were recovered from fecal pats suggesting this is important refuge for L3 survival. Results also show that L3 of several GIN parasite species can survive relatively efficiently on pastures even in the extreme winter conditions in western Canada. Tracer calf experiments confirmed that overwintered L3 of both C. oncophora and O. ostertagi were capable of establishing a patent infection in the following spring. These results have important implications for the epidemiology, risk of production impact and the design of effective control strategies. The work also illustrates the value of applying ITS2 nemabiome metabarcoding to environmental samples.

Evaluation of predation of the mite Lasioseius penicilliger (Aracnida: Mesostigmata) on Haemonchus contortus and bacteria-feeding nematodes

2012 ◽  
Vol 88 (1) ◽  
pp. 20-23 ◽  
Author(s):  
L. Aguilar-Marcelino ◽  
M.T. Quintero-Martínez ◽  
P. Mendoza de Gives ◽  
M.E. López-Arellano ◽  
E. Liébano-Hernández ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Nematode Species ◽  
Larval Stages ◽  
Panagrellus Redivivus ◽  
Third Stage ◽  
Petri Dishes

AbstractPredation by the mite Lasioseius penicilliger was studied on three nematode species, i.e. infective larval stages (L3) of Haemonchus contortus and adults of Panagrellus redivivus and Rhabditis sp. Experiments were carried out in 5.5-cm diameter Petri dishes containing 2% water-agar over a period of 5 days. Batches of up to 1500 third-stage larvae (L3) of H. contortus and 1000 adult nematodes of P. redivivus and Rhabditis sp. were exposed to five mites in separate Petri dishes. Upon contact, each mite used its pedipalp and legs to identify and hold its prey and then used its chelicerae to feed upon the prey. Predation by L. penicilliger was chance dependent but mites became aggregated around any injured/damaged prey, thereby suggesting some form of chemoperception. The rate of predation on the three species of nematodes was high but L3 of H. contortus and adult Rhabditis sp. were preferred.

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