Effect of selection pressure for thiabendazole resistance on fitness of Haemonchus contortus in sheep

Parasitology ◽  
1990 ◽  
Vol 100 (2) ◽  
pp. 327-335 ◽  
Author(s):  
N. Maingi ◽  
M. E. Scott ◽  
R. K. Prichard
Keyword(s):  
Haemonchus Contortus ◽  
Selection Pressure ◽  
Egg Hatch ◽  
Worm Recovery ◽  
Per Capita ◽  
Egg Hatch Assay ◽  
Severe Pathology ◽  
Larval Establishment

SUMMARYA Strain ofHaemonchus contortusshowing moderate levels of resistance to thiabendazole (TBZ) (egg hatch assay LC50 2.1 μM) was subjected, in alternating sequence, to 5 in vitro and 4 in vivo selections with TBZ. This resulted in a significant increase in resistance (egg hatch assay LC50 2.8 μM). The isolates obtained after each combined in vitro and in vivo selection were compared in terms of egg hatch assay, establishment, net egg output, per capita egg output and degree of pathology caused in infected hosts. The increase in resistance was accompanied by a significant increase in larval establishment sheep (22 %) and was associated with more severe pathology, higher egg count and worm recovery 3 months post- infection.

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.

scholarly journals Does the in vitro egg hatch test predict the failure of benzimidazole treatment in Haemonchus contortus?

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 62
Author(s):  
Michal Babják ◽  
Alžbeta Königová ◽  
Michaela Urda Dolinská ◽  
Tomas Kupčinskas ◽  
Jaroslav Vadlejch ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Gastrointestinal Parasites ◽  
Resistant Isolate ◽  
Egg Hatch ◽  
Larval Stages ◽  
Tubulin Isotype ◽  
Faecal Egg Count ◽  
Egg Hatch Test

Considerable research has been directed towards optimising in vitro tests that can diagnose resistance in pre-parasitic stages of parasites. The objective of this study was to compare the in vivo faecal egg count reduction test (FECRT), the in vitro egg hatch test (EHT), and the molecular determination of the frequency of a codon 200 allele of β-tubulin isotype 1 associated with benzimidazole resistance in larval stages of Haemonchus contortus obtained from infected goats. Animals were infected with composite infective doses representing 10, 20, 30, 40, 60, and 80% resistant alleles. Faecal samples for the EHT were collected on 28, 33, and 35 days post-infection. The results of the in vivo FECRT indicated that albendazole treatment reduced infections consisting of composite doses of 10, 20, 30, 40, 60, and 80% larvae of the resistant isolate by 91.3, 78.0, 63.3, 48.4, 36.5, and 41.4%, respectively. The drug concentration at which 50% of the eggs were prevented from developing hatching larvae (ED50) in the in vitro EHT varied from 0.09 ± 0.01 to 15.63 ± 12.10 μg/mL thiabendazole. The results of the in vitro EHT indicated that the test could estimate in vivo resistance well. The EHT could thus accurately estimate the in vivo efficacy of the drug and percentage of the resistance allele in the population using hatching parameters in delineation doses. This finding was also supported by comparing the FECRT data to the hatching percentages in the EHT on 30 goat farms in Slovakia with natural mixed infections of gastrointestinal parasites.

scholarly journals Oxfendazole Resistance in Gastrointestinal Nematodes of Beetal Goats at Livestock Farms of Punjab (Pakistan)

2007 ◽  
Vol 76 (1) ◽  
pp. 79-85 ◽  
Author(s):  
M. Saeed ◽  
Z. Iqbal ◽  
A. Jabbar
Keyword(s):  
Anthelmintic Resistance ◽  
Gastrointestinal Nematodes ◽  
Post Treatment ◽  
Egg Hatch ◽  
Treatment Frequency ◽  
Contributory Factors ◽  
Reduction Test ◽  
Egg Hatch Assay

This study was carried out to screen goat farms for anthelmintic resistance (AR) against oxfendazole (OXF) and to determine contributory factors for its development. For this purpose, Beetal goat farms (n = 18) were randomly selected, with natural mixed gastrointestinal nematodosis infection. In vivo (faecal egg count reduction test) and in vitro (egg hatch assay) tests were used to ascertain the presence of AR while a scorecard was used to determine the role of possible contributory factors for oxfendazole resistance. For in vivo test, the experimental animals were divided into two groups of 10 animals each; one group received OXF treatment, while the other served as control. Pre- and post-treatment coproculture was performed to identify the species and genera of nematodes. Egg hatch assay (EHA) was used to confirm the results of FECRT. Fecal egg count reduction test (FECRT) revealed the development of resistance on six farms and post-treatment larval cultures indicated Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, Teladorsagia circumcincta and Oesophagostomum spp. as dominant species with resistance. Furthermore, EHA confirmed the results of FECRT. Among the presumptive factors for AR, the highest composite score was for rotation of anthelmintics followed by treatment frequency, dose rate and nature of medication. The scorecard for the development of AR, used in this study, may be helpful for the assessment of contributory factors of AR.

Emergence of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae in vivo

2019 ◽  
Vol 74 (11) ◽  
pp. 3211-3216 ◽  
Author(s):  
Stephan Göttig ◽  
Denia Frank ◽  
Eleonora Mungo ◽  
Anika Nolte ◽  
Michael Hogardt ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Klebsiella Pneumoniae ◽  
Selection Pressure ◽  
Galleria Mellonella ◽  
Phenotypic Characterization ◽  
Infection Model ◽  
Development Of Resistance ◽  
Time Kill

Abstract Objectives The β-lactam/β-lactamase inhibitor combination ceftazidime/avibactam is active against KPC-producing Enterobacterales. Herein, we present molecular and phenotypic characterization of ceftazidime/avibactam resistance in KPC-3-producing Klebsiella pneumoniae that emerged in vivo and in vitro. Methods Sequence analysis of blaKPC-3 was performed from clinical and in vitro-generated ceftazidime/avibactam-resistant K. pneumoniae isolates. Time–kill kinetics and the Galleria mellonella infection model were applied to evaluate the activity of ceftazidime/avibactam and imipenem alone and in combination. Results The ceftazidime/avibactam-resistant clinical K. pneumoniae isolate revealed the amino acid change D179Y in KPC-3. Sixteen novel mutational changes in KPC-3 among in vitro-selected ceftazidime/avibactam-resistant isolates were described. Time–kill kinetics showed the emergence of a resistant subpopulation under selection pressure with either imipenem or ceftazidime/avibactam. However, combined selection pressure with imipenem plus ceftazidime/avibactam prevented the development of resistance and resulted in bactericidal activity. Concordantly, the G. mellonella infection model revealed that monotherapy with ceftazidime/avibactam is prone to select for resistance in vivo and that combination therapy with imipenem results in significantly better survival. Conclusions Ceftazidime/avibactam is a valuable antibiotic against MDR and carbapenem-resistant Enterobacterales. Based on time–kill kinetics as well as an in vivo infection model we postulate a combination therapy of ceftazidime/avibactam and imipenem as a strategy to prevent the development of ceftazidime/avibactam resistance in KPC-producing Enterobacterales in vivo.

scholarly journals In vitro and in vivo action of Piptadenia viridiflora (Kunth) Benth against Haemonchus contortus in sheep

2016 ◽  
Vol 223 ◽  
pp. 43-49 ◽  
Author(s):  
F. Morais-Costa ◽  
G.A. Bastos ◽  
A.C.M. Soares ◽  
E.G.L. Costa ◽  
V.O. Vasconcelos ◽  
...  
Keyword(s):  
Haemonchus Contortus

scholarly journals The SARS-CoV-2 Omicron (B.1.1.529) variant exhibits altered pathogenicity, transmissibility, and fitness in the golden Syrian hamster model

2022 ◽  
Author(s):  
Shuofeng Yuan ◽  
Zi-Wei Ye ◽  
Ronghui Liang ◽  
Kaiming Tang ◽  
Anna Jinxia Zhang ◽  
...  
Keyword(s):  
Syrian Hamster ◽  
Neutralizing Antibodies ◽  
Selection Pressure ◽  
Immune Selection ◽  
Hamster Model ◽  
Golden Syrian Hamster ◽  
New Variant ◽  
Contact Transmission

The newly emerging SARS-CoV-2 Omicron (B.1.1.529) variant first identified in South Africa in November 2021 is characterized by an unusual number of amino acid mutations in its spike that renders existing vaccines and therapeutic monoclonal antibodies dramatically less effective. The in vivo pathogenicity, transmissibility, and fitness of this new Variant of Concerns are unknown. We investigated these virological attributes of the Omicron variant in comparison with those of the currently dominant Delta (B.1.617.2) variant in the golden Syrian hamster COVID-19 model. Omicron-infected hamsters developed significantly less body weight losses, clinical scores, respiratory tract viral burdens, cytokine/chemokine dysregulation, and tissue damages than Delta-infected hamsters. The Omicron and Delta variant were both highly transmissible (100% vs 100%) via contact transmission. Importantly, the Omicron variant consistently demonstrated about 10-20% higher transmissibility than the already-highly transmissible Delta variant in repeated non-contact transmission studies (overall: 30/36 vs 24/36, 83.3% vs 66.7%). The Delta variant displayed higher fitness advantage than the Omicron variant without selection pressure in both in vitro and in vivo competition models. However, this scenario drastically changed once immune selection pressure with neutralizing antibodies active against the Delta variant but poorly active against the Omicron variant were introduced, with the Omicron variant significantly outcompeting the Delta variant. Taken together, our findings demonstrated that while the Omicron variant is less pathogenic than the Delta variant, it is highly transmissible and can outcompete the Delta variant under immune selection pressure. Next-generation vaccines and antivirals effective against this new VOC are urgently needed.

scholarly journals In vitro Efficacy of Albendazole against Strongyle eggs recovered from Trade Goats slaughtered at the Nsukka Abattoir: A Preliminary Survey of Resistance to Albendazole

2021 ◽  
Vol 40 (4) ◽  
pp. 287-295
Author(s):  
I.K. Idika ◽  
V.J. Ebuk ◽  
E.I. Okoro ◽  
T.A. Nzeakor ◽  
N.M. Uzonnah ◽  
...  
Keyword(s):  
Faecal Sample ◽  
Anthelmintic Resistance ◽  
Egg Hatch ◽  
Lc50 Value ◽  
Nematode Parasites ◽  
Faecal Culture ◽  
World Association ◽  
Egg Hatch Assay ◽  
Set Up

The efficacy of Albendazole against trichostrongyle nematode parasites in goats presented for slaughter at the Nsukka municipal  abattoir was evaluated using the In vitro Egg hatch assay (EHA) model. The abattoir was visited once every week for 4 consecutive months during which a total of 240 goats were sampled. Fecal samples were collected per rectum from a minimum of 15 goats on each day of the visit. Egg Hatch Assay was performed on strongyle eggs recovered from pooled faecal sample on each day of sampling with a 2.5% W/V Albendazole. Faecal culture was also set up from the pooled faecal sample on each sampling day to recover and identify the nematode parasites present in the goats. Among the 240 goats sampled, the prevalence of trichostrongylosis as observed by the presence of strongyle eggs was 94.6% (227/240). Faecal culture and larval identification revealed 69.8% of the strongyles as  Haemonchus contortus, while 25.5 and 4.8% were Trichostrongylus colubriformis and Oesophagostomum species respectively. In the EHA, Albendazole had mean LC50 value of 0.16 µg/ml which is slightly in excess of the discriminating dose of 0.1µg/ml as prescribed by the World Association for the Advancement of Veterinary Parasitology (WAAVP) as an indication of anthelmintic resistance. There is therefore an urgent need to screen the nematode parasite population in the Nigeria for the presence Albendazole resistance genes. Key words: GI nematode; egg hatch assay; goat; Albendazole; Resistance; Nigeria

Kinetics of exsheathment of infective ovine and bovine strongylid larvae in vivo and in vitro

Parasitology ◽  
2002 ◽  
Vol 125 (1) ◽  
pp. 65-70 ◽  
Author(s):  
H. HERTZBERG ◽  
U. HUWYLER ◽  
L. KOHLER ◽  
St REHBEIN ◽  
M. WANNER
Keyword(s):  
Haemonchus Contortus ◽  
Buffer System ◽  
Bicarbonate Concentration ◽  
Infective Larvae ◽  
Nylon Mesh ◽  
Mesh Bags ◽  
Sheep Rumen ◽  
Kinetics Of

The aim of the study was to investigate the longitudinal changes of exsheathment of ovine and bovine 3rd-stage strongylid larvae in an artificial rumen (RUSITEC) and to compare the results with in vivo data obtained from rumen-fistulated sheep. Infective larvae were incubated in nylon mesh bags in the sheep rumen or the RUSITEC apparatus for periods of 1, 6 and 12 h, respectively. The 12 h exsheathment rates in the rumen and the RUSITEC apparatus (in parentheses) were as follows: Haemonchus contortus: 100% (100%), Ostertagia circumcincta: 100% (76%), O. leptospicularis: 100% (100%), O. ostertagi: 53% (59%), Trichostrongylus axei: 100% (100%), T. colubriformis: 37% (36%), Cooperia curticei: 94% (76%), C. oncophora: 95% (89%), Nematodirus filicollis: 0% (N.D.), N. spathiger: 11% (15%), N. battus: 7% (5%), Oesophagostomum venulosum: 17% (9%), Chabertia ovina: 7% (2%), Dictyocaulus filaria: 1% (N.D.). Larvae of Nematodirus spp. and T. colubriformis showed a quick rise of the exsheathment rate 2 h after transfer into the abomasum. These results confirm that exsheathment generally occurs in the part of the gastrointestinal tract immediately anterior to the habitat of the adult parasite. The overall similar course of exsheathment in both systems indicates that the essential stimuli for exsheathment were generated and maintained under in vitro conditions of the artificial rumen. In both systems, the bicarbonate concentration and the pH reflected a similar status of the H2CO3/HCO buffer system, which is known to provide the essential stimuli for larval exsheathment of the abomasal species. These results give evidence that the RUSITEC system represents a valid system for studying the kinetics of exsheathment of strongylid nematodes under in vitro conditions. For 7 of the species investigated the obtained results represent the first data on larval exsheathment in vivo and in vitro.

scholarly journals In Vitro Anthelmintic Activity of Crude Extracts of Artemisia herba-alba and Punica granatum against Haemonchus contortus

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Aliyi Hassen Ahmed ◽  
Mebrat Ejo ◽  
Teka Feyera ◽  
Dereje Regassa ◽  
Bahar Mummed ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Anthelmintic Activity ◽  
Punica Granatum ◽  
Limiting Factor ◽  
Egg Hatching ◽  
Traditional Use ◽  
Egg Hatch ◽  
Inhibition Effect ◽  
Crude Extracts

Gastrointestinal nematodes (GINs) are the major limiting factor for the successfulness of livestock production throughout the world. Emergence of resistance strains as well as scarcity and high cost of the currently available drugs has led to the evaluation of other alternative helminth control options, mainly from plants. The current study is aimed at investigating the in vitro anthelmintic efficacy of crude methanolic extracts of two traditionally important medicinal plants, Artemisia herba-alba and Punica granatum, against Haemonchus contortus using adult motility assay (AMA) and egg hatch inhibition assay (EHIA). Four graded concentrations of the extracts were tested for both the AMA (10, 5, 2.5, and 1.25 mg/mg) and EHIA (0.1, 0.25, 0.5, and 1 mg/mL) in replicates. Albendazole and phosphate-buffered saline (AMA) or distilled water (EHIA) were used as the positive and negative controls, respectively. The crude extracts of A. herba-alba and P. granatum exhibited a potential anthelmintic activity at all dose levels in a concentration- and time-dependent fashion. The highest concentration (10 mg/mL) of all the extracts caused a significantly (p<0.05) superior nematocidal activity compared to the negative control. Moreover, significant and concentration-dependent egg hatching inhibition effect was observed from both plant extracts. Maximal (98.67%) egg hatching inhibition effect was exhibited by the flower extract of A. herba-alba at 1 mg/mL concentration. The relative egg hatch inhibition efficacy indicated that both plants caused a significantly (p<0.05) greater egg hatch inhibition within 48 hr of exposure. The current study validated the traditional use of both plants as a natural anthelmintic against H. contortus justifying a need to undertake detail pharmacological and toxicological investigation on both plants.

scholarly journals Efficiency of the Bioverm® (Duddingtonia flagrans) fungal formulation to control in vivo and in vitro of Haemonchus contortus and Strongyloides papillosus in sheep

3 Biotech ◽  
2020 ◽  
Vol 10 (2) ◽  
Author(s):  
Fábio Ribeiro Braga ◽  
Carolina Magri Ferraz ◽  
Edir Nepomuceno da Silva ◽  
Jackson Victor de Araújo
Keyword(s):  
Haemonchus Contortus ◽  
Duddingtonia Flagrans
Sign in / Sign up

Export Citation Format

Share Document