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Field studies on the biological control of nematode parasites of sheep in the tropics, using the microfungus Duddingtonia flagrans

Chandrawathani P, Jamnah O, Adnan M, Waller PJ, Larsen M, Gillespie AT

Vet Parasitol, 2004 Mar 25;120(3):177-87.
PMID: 15041093

Long-term field studies were conducted on two government managed small ruminant research farms, located in different geo-climatic regions and approximately 300 km separate from each other, on Peninsula Malaysia. The Infoternak trial (48 weeks) and the Chalok trial (43 weeks) each compared nematode parasite control in separately managed groups of young sheep, either short-term rotationally grazed around a suite of 10 paddocks in addition to receiving a daily supplement of Duddingtonia flagrans spores (Fungus Group); or similar groups of sheep being rotationally grazed alone (Control Group). The prevailing weather conditions at Infoternak farm were of below average rainfall conditions for the most of the trial. As a consequence, only very low worm infections (almost exclusively Haemonchus contortus) were acquired by the 17 sets of tracer lambs that grazed sequentially with the experimental lambs. However on all except 2 occasions in the early part of the trial, the mean tracer worm burdens were significantly lower (P < 0.05) and the experimental lambs grew significantly better (P = 0.054) in the Fungus Group. Rainfall at Chalok farm during the course of the trial was also below average. As a consequence infectivity of pastures was assumed to be relatively low based on faecal egg counts (epg) of the experimental sheep, which following an anthelmintic treatment prior to allocation, remained very low in both treatment groups. Faecal egg counts of undosed replacement lambs in the latter half of the Chalok study, showed a progressive increase in the Control Group to levels exceeding 3000 epg, whereas the Fungus Group remained static at approximately 500 epg. These results show that the deployment of the nematophagous fungus, D. flagrans, can improve the level of parasite control of sheep in the tropics above that which can be achieved by the short-term rotational grazing strategy alone.

Matched MeSH terms: Haemonchiasis/parasitology; Haemonchiasis/prevention & control*; Haemonchiasis/veterinary*
Morphological identification of adult male Haemonchus species in goats from Thailand and Lao PDR

Vongnady K, Rucksaken R, Mangkit B

Trop Biomed, 2020 Sep 01;37(3):691-712.
PMID: 33612783 DOI: 10.47665/tb.37.3.691

Haemonchus spp. or barber's pole worms are one of the most highly pathogenic nematodes of ruminants causing economic losses in livestock worldwide. The current study was a first attempt to identify Haemonchus spp. from goats in Thailand and Lao PDR. Utilizing the inexpensive tools of the discriminant function (DF) combined with synlophe patterns is fundamental for understanding their epidemiological aspects. In total, 255 randomly chosen adult male Haemonchus worms from goats in various areas in each country were identified individually. For both these countries, about 94% based on the DF values, and 99%, 98%, and 97% based on synlophe patterns in the region of the esophageal intestinal junction (EI), 4 mm from the anterior end, and at both these positions, respectively, were identified as H. contortus. Other identified specimens defined as H. placei and hybrids as well as unclassified species based on synlophe patterns were proved using polymerase chain reaction (PCR); this also included some randomly chosen H. contortus by DF and synlophe patterns. All those specimens were confirmed as H. contortus being strongly supported by some genetic evidences and UPGMA analysis. Thus, it was assumed that all specimens in the current study were H. contortus. The morphological differences of this predominant species (H. contortus) in goats between the two countries were: body length, gubernaculum length, and left spicule barb length, while almost all characters of male worms individually measured appeared to overlap, mostly in H. contortus and H. placei, which may lead to misclassification. Therefore, using the DF along with synlophe patterns can assist in increasing the accuracy of Haemonchus spp. identification from goats in some areas where funding is limited, particularly in Lao PDR. The present results revealed that synlophe patterns in the EI region seemed to be promising for the identification of Haemonchus spp., while molecular techniques are also required to address ambiguous identification with some specimens.

Matched MeSH terms: Haemonchiasis
Kinetics of IgA and eosinophils following a low-dose, predominantly Haemonchus contortus infection of Boer goats

Hayyan BN, Sharma RSK, Raimy N, Nisha M, Hussain K, Busin VM, et al.

Parasite Immunol., 2020 06;42(6):e12707.
PMID: 32118305 DOI: 10.1111/pim.12707

AIMS: Most breeds of goat are more susceptible to nematode infection than sheep, and this appears to be a consequence of less effective immune responses. Several papers have considered the effectiveness of eosinophils and immunoglobulin A (IgA) in goats but differences in the induction of responses have not been studied in the same detail. The aim of this study was to look at the induction of eosinophil and IgA responses in Boer goats reared indoors under intensive conditions.
METHODS AND RESULTS: The goats were experimentally infected with a low dose of 2400 Haemonchus contortus, Trichostrongylus spp. and Oesophagostomum spp. at a 6:1:1 ratio. Faecal egg counts (FEC), packed cell volume (PCV), IgA activity against third-stage larvae and peripheral eosinophilia were measured twice a week for eight weeks. The infection generated an IgA response but did not significantly increase peripheral eosinophilia in the 25 infected kids compared with the 4 control animals. FEC was not associated with IgA activity or eosinophilia.
CONCLUSION: A detailed analysis of IgA and eosinophil responses to deliberate nematode infection in Boer goats showed that there was an increase in nematode-specific IgA activity but no detectable eosinophil response. In addition, there was no association between increased IgA activity or eosinophilia with egg counts and worm burdens. These suggest that IgA and eosinophils do not act to control nematode infection in goats.

Matched MeSH terms: Haemonchiasis/immunology; Haemonchiasis/parasitology; Haemonchiasis/veterinary*
Dietary protein influences on regulation of Haemonchus contortus populations in Dorsimal lambs

Israf DA, Zainal MJ, Ben-Gheshir MA, Rasedee A, Sani RA, Noordin MM

J Helminthol, 1998 Jun;72(2):143-6.
PMID: 9687595

The influence of dietary protein supplementation upon resistance to haemonchosis was examined in Dorsimal (Polled Dorset x Malin) lambs offered two levels of protein. Lambs were offered either a complete basal ruminant diet (15% crude protein (CP)) or the same diet supplemented with fish meal as a source of rumen bypass protein (19% CP). Lambs from each dietary treatment group were given either a 7-week trickle infection with Haemonchus contortus infective larvae (L3) or remained uninfected. All lambs were drenched with anthelmintic at week 8 post-infection (PI), challenged with a single dose of 5000 H. contortus L3 one week later, and killed 14 days post-challenge (PC). Lambs on the supplemented diet that were trickle infected showed a significant reduction in egg output. Supplementation and previous infection did not affect either growth rate, worm burden, worm development or haematological parameters. There was a trend for enhanced growth among supplemented non-infected lambs in comparison to lambs which received the basal ration.

Matched MeSH terms: Haemonchiasis/immunology*
Sympatric species distribution, genetic diversity and population structure of Haemonchus isolates from domestic ruminants in Pakistan

Hussain T, Periasamy K, Nadeem A, Babar ME, Pichler R, Diallo A

Vet Parasitol, 2014 Dec 15;206(3-4):188-99.
PMID: 25468018

Haemonchus species are major gastro-intestinal parasites affecting ruminants across the world. The present study aimed to assess the sympatric species distribution, genetic diversity, population structure and frequency of β-tubulin isotype 1 alleles associated with benzimidazole resistance. Internal transcribed spacer 2 (ITS2) sequences revealed three sympatric species of Haemonchus, H. contortus, H. placei and H. longistipes with 12 distinct genotypes circulating among ruminant hosts in Pakistan. High genetic variability was observed in Pakistani Haemonchus isolates at nicotine amide dehydrogenase subunit 4 (ND4) and cytochrome oxidase subunit 1 (COI) gene loci. Intra-population diversity parameters were higher in H. contortus isolates than H. placei. Phylogenetic analysis of ND4 and COI sequences did not reveal clustering of haplotypes originating from a particular host indicating high rate of gene flow among Haemonchus parasites infecting sheep, goat and cattle in Pakistan. ND4 and COI haplotypes from Pakistan were compared to sequences of Haemonchus isolates from 11 countries to elucidate the population structure. Multidimensional scaling (MDS) plot of pairwise FST derived from 531 ND4 haplotypes revealed clustering together of H. contortus from Pakistan, China, Malaysia and Italy while the isolates from Yemen and United States were found to be genetically distinct. With respect to H. placei, isolates from Pakistan were found to be genetically differentiated from isolates of other countries. The tests for selective neutrality revealed negative D statistics and did not reveal significant deviations in Pakistani Haemonchus populations while significant deviation (P < 0.05) was observed in Brazilian and Chinese H. contortus populations. Median Joining (MJ) network of ND4 haplotypes revealed Yemenese H. contortus being closer to H. placei cluster. β-tubulin isotype 1 genotyping revealed 7.86% frequency of Y allele associated with benzimidazole resistance at F200Y locus in Pakistani Haemonchus isolates.

Matched MeSH terms: Haemonchiasis/parasitology; Haemonchiasis/veterinary*
Fulltext Genetic variability within and among Haemonchus contortus isolates from goats and sheep in China

Yin F, Gasser RB, Li F, Bao M, Huang W, Zou F, et al.

Parasit Vectors, 2013 Sep 25;6(1):279.
PMID: 24499637 DOI: 10.1186/1756-3305-6-279

BACKGROUND: Haemonchus contortus (order Strongylida) is a common parasitic nematode infecting small ruminants and causing significant economic losses worldwide. Knowledge of genetic variation within and among H. contortus populations can provide a foundation for understanding transmission patterns, the spread of drug resistance alleles and might assist in the control of haemonchosis.
METHODS: 152 H. contortus individual adult worms were collected from seven different geographical regions in China. The second internal transcribed spacer (ITS-2) of the nuclear ribosomal DNA and mitochondrial nicotinamide dehydrogenase subunit 4 gene (nad4) were amplified by polymerase chain reaction (PCR) and sequenced directly. The sequence variations and population genetic diversities were determined.
RESULTS: Nucleotide sequence analyses revealed 18 genotypes (ITS-2) and 142 haplotypes (nad4) among the 152 worms, with nucleotide diversities of 2.6% and 0.027, respectively, consistent with previous reports from other countries, including Australia, Brazil, Germany, Italy, Malaysia, Sweden, the USA and Yemen. Population genetic analyses revealed that 92.4% of nucleotide variation was partitioned within populations; there was no genetic differentiation but a high gene flow among Chinese populations; some degree of genetic differentiation was inferred between some specimens from China and those from other countries.
CONCLUSIONS: This is the first study of genetic variation within H. contortus in China. The results revealed high within-population variations, low genetic differentiation and high gene flow among different populations of H. contortus in China. The present results could have implications for studying the epidemiology and ecology of H. contortus in China.

Matched MeSH terms: Haemonchiasis/parasitology; Haemonchiasis/veterinary*
Epidemiology of gastro-intestinal nematodes of sheep in wet tropical conditions in Malaysia

Cheah TS, Rajamanickam C

Trop Anim Health Prod, 1997 Aug;29(3):165-73.
PMID: 9316233

A study on the seasonal variations in the population structure of Haemonchus contortus and Trichostronglyus colubriformis was conducted for a period of 12 months in a typical large scale sheep farm on improved pasture in Peninsular Malaysia which has a wet tropical climate. Successive groups of helminth-free tracer lambs were grazed for 4 weeks together with naturally infected sheep and were necropised for worm counts 2 weeks after their removal from the pasture. The monthly populations of H. contortus fluctuated slightly except in May and August during which more worms were found in the tracer animals. The numbers of T. colubriformis were comparatively high from October to December 1992 and again in March 1993, low during April and June 1992. Small numbers of hypobiotic larvae of H. contortus were detected in the tracer animals. Development and survival of infective larvae of H. contortus and T. colubriformis on pasture were investigated by spreading faeces containing eggs on grass plots in October 1993, February and May 1994. Development of the eggs to the infective larvae occurred within one week and their survival times were 7 weeks in the 3 experiments. The potential for control by rotational grazing is discussed.

Matched MeSH terms: Haemonchiasis/epidemiology; Haemonchiasis/veterinary*
Multiple and multigeneric anthelmintic resistance on a sheep farm in Malaysia

Sivaraj S, Dorny P, Vercruysse J, Pandey VS

Vet Parasitol, 1994 Oct;55(1-2):159-65.
PMID: 7886917

The anthelmintic efficacy of benzimidazoles, levamisole, closantel, ivermectin and moxidectin was evaluated on an institutional farm in Malaysia using faecal egg count reduction tests, controlled slaughter trials and an in vitro egg hatch assay. The results of this study indicated simultaneous resistance of Haemonchus contortus against benzimidazoles and ivermectin and of Trichostrongylus colubriformis against benzimidazoles and levaminsole on the same farm. Moxidectin was effective against the ivermectin resistant H. contortus.

Matched MeSH terms: Haemonchiasis/drug therapy; Haemonchiasis/veterinary*
Characterization of benzimidazole resistance in Haemonchus contortus: integration of phenotypic, genotypic and proteomic approaches

Tan TK, Lim YAL, Chua KH, Chai HC, Low VL, Bathmanaban P, et al.

Parasitol Res, 2020 Sep;119(9):2851-2862.
PMID: 32651637 DOI: 10.1007/s00436-020-06790-5

The field strain of Haemonchus contortus has a long history of anthelmintic resistance. To understand this phenomenon, the benzimidazole resistance profile was characterized from the Malaysian field-resistant strain by integrating phenotypic, genotypic and proteomic approaches. The faecal egg count reduction test (FECRT) demonstrated that benzimidazole resistance was at a critical level in the studied strain. The primary resistance mechanism was attributed to F200Y mutation in the isotype 1 β-tubulin gene as revealed by AS-PCR and direct sequencing. Furthermore, the protein response of the resistant strain towards benzimidazole (i.e., albendazole) treatment was investigated via two-dimensional difference gel electrophoresis (2D-DIGE) and tandem liquid chromatography-mass spectrometry (LC-MS/MS). These investigations illustrated an up-regulation of antioxidant (i.e., ATP-binding region and heat-shock protein 90, superoxide dismutase) and metabolic (i.e., glutamate dehydrogenase) enzymes and down-regulation of glutathione S-transferase, malate dehydrogenase, and other structural and cytoskeletal proteins (i.e., actin, troponin T). Findings from this study are pivotal in updating the current knowledge on anthelmintic resistance and providing new insights into the defence mechanisms of resistant nematodes towards drug treatment.

Matched MeSH terms: Haemonchiasis/drug therapy
Anthelmintic resistance in sheep and goat farms on Peninsular Malaysia

Chandrawathani P, Adnan M, Waller PJ

Vet Parasitol, 1999 May;82(4):305-10.
PMID: 10384906

The faecal egg count reduction test (FECRT) was conducted on 39 sheep farms and 9 goat farms located in Peninsular Malaysia. The anthelmintic groups used in these tests were the benzimidazoles, levamisole, the benzimidazole/levamisole combination, macrocyclic lactones and closantel. Results indicated that the prevalence of resistance to the benzimidazole group was high, with approximately 50% of the sheep farms and 75% of the goat farms having resistant nematode parasite populations present. Resistance to levamisole, closantel and ivermectin was also detected. Differentiation of the infective larvae derived from faecal cultures indicated that by far the most predominant parasite species was Haemonchus contortus.

Matched MeSH terms: Haemonchiasis/drug therapy*

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