Displaying publications 1 - 20 of 26 in total

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  1. Blood gastrin and pepsinogen responses of native village goats in Malaysia to infection with Haemonchus contortus
    Fox MT, Jacobs DE, Sani RA
    Ann Trop Med Parasitol, 1991 Apr;85(2):263-7.
    PMID: 1796870
    Blood gastrin and pepsinogen responses of native village goats in Malaysia to a single dose of 10,500 infective Haemonchus contortus larvae were investigated. Both blood values were significantly elevated within a week of infection and exhibited a highly significant correlation during the study. The magnitude of the blood gastrin response was, however, significantly greater than that of pepsinogen during the period that both blood values were elevated. It is suggested that blood gastrin assay may be of particular value in the diagnosis of chronic haemonchosis in animals harbouring relatively light worm burdens.
    Matched MeSH terms: Haemonchiasis/veterinary*
  2. Seasonal changes in the prevalence of Haemonchus and Trichostrongylus hypobiotic larvae in tracer goats in Malaysia
    Ikeme MM, Iskander F, Chong LC
    Trop Anim Health Prod, 1987 Aug;19(3):184-90.
    PMID: 3660455
    An investigation into the seasonal changes in the population structure of Haemonchus and Trichostrongylus in tracer goats was conducted over 12 months at Serdang, an area in southern West Malaysia with year-round tropical rainfall. Successive groups of parasite-free tracer goats were grazed for a month alongside naturally infected adult goats and necropsied for worm counts 14 days after their removal from pasture. No hypobiotic larvae of Trichostrongylus were recovered. Hypobiotic larvae of Haemonchus were evident during each month of the year but accounted for only a very small proportion of the total Haemonchus burden. Very low levels were encountered from December through to June. Comparatively higher levels of hypobiosis were observed thereafter with a peak of 7.4% in September. The factors responsible for hypobiosis were not clearly defined but the phenomenon was associated with increasing levels of soil moisture storage. Host resistance, adult worm population of tracers and population of ingested L3 were ruled out as possible inducing factors.
    Matched MeSH terms: Haemonchiasis/veterinary*
  3. The role of concurrent haemonchosis in the development of pneumonic pasteurellosis in goats
    Zamri-Saad M, Subramaniam P, Sheikh-Omar AR, Sani RA, Rasedee A
    Vet Res Commun, 1994;18(2):119-22.
    PMID: 7975196
    Matched MeSH terms: Haemonchiasis/veterinary*
  4. Changes in liveweight gain and blood constituents in experimental infection of goats with a goat-derived compared with a sheep-derived strain of Haemonchus contortus
    Rahman WA, Collins GH
    Vet Parasitol, 1991 Mar;38(2-3):145-53.
    PMID: 1858284
    Two groups of goats were experimentally infected with two different strains of Haemonchus contortus and compared with the controls. Group A animals were infected with a goat-derived strain (GDS) while Group B animals were infected with a sheep-derived strain (SDS). Changes in the liveweights and some blood constitutents between the two infected groups were compared. The pathogenic effects of the GDS larvae were generally more serious when compared with those of the SDS larvae.
    Matched MeSH terms: Haemonchiasis/veterinary*
  5. Changes in liveweight gain, blood constituents and worm egg output in goats artificially infected with a sheep-derived strain of Haemonchus contortus
    Rahman WA, Collins GH
    Br. Vet. J., 1990 Nov-Dec;146(6):543-50.
    PMID: 2271911
    Two groups of goats were dosed with 10,000 and 20,000 sheep-derived strain (SDS) larvae of Haemonchus contortus respectively. Over a period of 42 days goats dosed with 20,000 larvae lost more weight than those dosed with 10,000 larvae. Infected goats showed anaemia from about 2 weeks after infection as well as reduced levels of total serum proteins and albumins.
    Matched MeSH terms: Haemonchiasis/veterinary*
  6. Infection of goats with Haemonchus contortus and Trichostrongylus colubriformis: histopathology and pH changes
    Rahman WA, Collins GH
    Br. Vet. J., 1991 Nov-Dec;147(6):569-74.
    PMID: 1777801
    Two groups of goats were experimentally infected with Haemonchus contortus and Trichostrongylus colubriformis, and killed at various days after infection (DAI). The percentage of worms that established in the abomasum and the small intestine was low. At necropsy, abomasums from infected goats had thickened walls and oedematous folds. At 7 DAI there was an initial infiltration of eosinophils and some neutrophils which tend to increase with age of infection. The mean pH of the abomasum in goats infected with H. contortus was 5.43 (range 5.3-5.7), while that of the control goats was 3.30 (range 2.8-3.7).
    Matched MeSH terms: Haemonchiasis/veterinary*
  7. Fulltext Morphological characterization of Haemonchus contortus in goats (Capra hircus) and sheep (Ovis aries) in Penang, Malaysia
    Rahman WA, Abd Hamid S
    Trop Biomed, 2007 Jun;24(1):23-7.
    PMID: 17568374 MyJurnal
    The large stomach worm, Haemonchus contortus is an important pathogen of goats (Capra hircus) and sheep (Ovis aries). This paper describes characteristics of surface cuticular ridges (synlophe) of H. contortus adults from the two hosts. There were more ridges in H. contortus from goats compared to that from sheep. Total body length, vulvar morphology, spicule length and cervical papillae had been considered as markers of physical adaptation and were studied and described.
    Matched MeSH terms: Haemonchiasis/veterinary*
  8. Fulltext Haemonchus contortus: parasite problem No. 1 from tropics - Polar Circle. Problems and prospects for control based on epidemiology
    Peter JW, Chandrawathani P
    Trop Biomed, 2005 Dec;22(2):131-7.
    PMID: 16883278 MyJurnal
    There is no doubt that on a global basis, Haemonchus contortus is by far the most important parasite of small ruminants (sheep and goats). This is particularly more so now, with the development of high levels of resistance to both the broad and narrow spectrum anthelmintic drugs in H. contortus throughout the world. Epidemiological studies describe the lower environmental limits for haemonchosis to occur in sheep, as being a mean monthly temperature of 18C and approximately 50mm rainfall. Thus it has been generally recognised that H. contortus is a problem parasite restricted to the warm, wet countries where sheep and goats are raised. However, recent evidence shows that this parasite is apparently common even in northern Europe. Thus the need for sustainable control strategies for H. contortus is becoming much more pressing. This report highlights two examples of sustainable and highly efficient control programmes for H. contortus, that can be implemented in regions at the extremes of its geographic range (Malaysia and Sweden), where the authors have had direct involvement.
    Matched MeSH terms: Haemonchiasis/veterinary*
  9. Fulltext Co-infection of Haemonchus contortus and Trichostrongylus spp. among livestock in Malaysia as revealed by amplification and sequencing of the internal transcribed spacer II DNA region
    Tan TK, Panchadcharam C, Low VL, Lee SC, Ngui R, Sharma RS, et al.
    BMC Vet Res, 2014;10:38.
    PMID: 24502557 DOI: 10.1186/1746-6148-10-38
    Haemonchus contortus and Trichostrongylus spp. are reported to be the most prevalent and highly pathogenic parasites in livestock, particularly in small ruminants. However, the routine conventional tool used in Malaysia could not differentiate the species accurately and therefore limiting the understanding of the co-infections between these two genera among livestock in Malaysia. This study is the first attempt to identify the strongylids of veterinary importance in Malaysia (i.e., H. contortus and Trichostrongylus spp.) by amplification and sequencing of the Internal Transcribed Spacer II DNA region.
    Matched MeSH terms: Haemonchiasis/veterinary*
  10. Evolution of high-level, multiple anthelmintic resistance on a sheep farm in Malaysia
    Chandrawathani P, Waller PJ, Adnan M, Höglund J
    Trop Anim Health Prod, 2003 Feb;35(1):17-25.
    PMID: 12636358
    Anthelmintic resistance in nematode parasites of sheep and goats on a government farm in north Malaysia was monitored over a 3-year period (1997-2000). The faecal egg count reduction test (FECRT) was conducted on young sheep at the beginning and end of this period. Changes in management, designed to reduce the selection pressure for the development of anthelmintic resistance, were also implemented during this time. By far the most important parasite problem was Haemonchus contortus. In 1997, this nematode was found to be resistant to levamisole, with suspected resistance to closantel and moxidectin. However, when the FECRT was repeated 3 years later, its resistance status had become much more severe, with resistance to benzimidazole, levamisole and ivermectin, and suspected resistance to moxidectin. This rapid evolution to multiple anthelmintic resistance is a major concern that needs to be arrested. There is an urgent need to evaluate other control strategies that incorporate livestock management, the 'smart' use of drugs and non-chemotherapeutic approaches, such as biological control agents.
    Matched MeSH terms: Haemonchiasis/veterinary*
  11. Resistance to benzimidazole anthelmintics by Haemonchus contortus in goats in peninsular Malaysia
    Rahman WA
    Vet Parasitol, 1994 Oct;55(1-2):155-7.
    PMID: 7886916
    A previous study had suggested that local strains of goat trichostrongyles, comprising largely Haemonchus contortus, might have developed resistance to benzimidazole anthelmintics. A trial involving 18 goats was conducted to confirm this. There was a significant (P < 0.01) reduction in worm burdens in goats given levamisole, but this was not so for those animals given albendazole, fenbendazole, oxfendazole and mebendazole (P > 0.05).
    Matched MeSH terms: Haemonchiasis/veterinary*
  12. Fulltext Genetic diversity of Haemonchus contortus isolated from sympatric wild blue sheep (Pseudois nayaur) and sheep in Helan Mountains, China
    Shen DD, Wang JF, Zhang DY, Peng ZW, Yang TY, Wang ZD, et al.
    Parasit Vectors, 2017 Sep 19;10(1):437.
    PMID: 28927469 DOI: 10.1186/s13071-017-2377-0
    BACKGROUND: Haemonchus contortus is known among parasitic nematodes as one of the major veterinary pathogens of small ruminants and results in great economic losses worldwide. Human activities, such as the sympatric grazing of wild with domestic animals, may place susceptible wildlife hosts at risk of increased prevalence and infection intensity with this common small ruminant parasite. Studies on phylogenetic factors of H. contortus should assist in defining the amount of the impact of anthropogenic factors on the extent of sharing of agents such as this nematode between domestic animals and wildlife.

    METHODS: H. contortus specimens (n = 57) were isolated from wild blue sheep (Pseudois nayaur) inhabiting Helan Mountains (HM), China and additional H. contortus specimens (n = 20) were isolated from domestic sheep that were grazed near the natural habitat of the blue sheep. Complete ITS2 (second internal transcribed spacer) sequences and partial sequences of the nad4 (nicotinamide dehydrogenase subunit 4 gene) gene were amplified to determine the sequence variations and population genetic diversities between these two populations. Also, 142 nad4 haplotype sequences of H. contortus from seven other geographical regions of China were retrieved from database to further examine the H. contortus population structure.

    RESULTS: Sequence analysis revealed 10 genotypes (ITS2) and 73 haplotypes (nad4) among the 77 specimens, with nucleotide diversities of 0.007 and 0.021, respectively, similar to previous studies in other countries, such as Pakistan, Malaysia and Yemen. Phylogenetic analyses (BI, MP, NJ) of nad4 sequences showed that there were no noticeable boundaries among H. contortus populations from different geographical origin and population genetic analyses revealed that most of the variation (94.21%) occurred within H. contortus populations. All phylogenetic analyses indicated that there was little genetic differentiation but a high degree of gene flow among the H. contortus populations among wild blue sheep and domestic ruminants in China.

    CONCLUSIONS: The current work is the first genetic characterization of H. contortus isolated from wild blue sheep in the Helan Mountains region. The results revealed a low genetic differentiation and high degree of gene flow between the H. contortus populations from sympatric wild blue sheep and domestic sheep, indicating regular cross-infection between the sympatrically reared ruminants.

    Matched MeSH terms: Haemonchiasis/veterinary*
  13. Isolation of an ivermectin-resistant strain of Haemonchus contortus from sheep in Malaysia
    Sivaraj S, Pandey VS
    Vet Rec, 1994 Sep 24;135(13):307-8.
    PMID: 7817517
    Matched MeSH terms: Haemonchiasis/veterinary*
  14. Effect of subclinical Eimeria species infections in tropical goats subsequently challenged with caprine Haemonchus contortus
    Rahman WA
    Vet Rec, 1994 Mar 05;134(10):235-7.
    PMID: 8197681
    Fourteen goat kids of the local indigenous breed naturally infected with Eimeria species were divided into two equal groups. The first group was superinfected with 500,000 Eimeria species oocysts and the second group was treated with amprolium. Sixty days later both groups were infected with 5000 third-stage caprine Haemonchus contortus larvae. The goats experimentally superinfected with eimeria shed more H contortus eggs and gained weight more slowly.
    Matched MeSH terms: Haemonchiasis/veterinary*
  15. Benzimidazole resistance of Haemonchus contortus in goats in Malaysia
    Dorny P, Claerebout E, Vercruysse J, Jalila A, Sani R
    Vet Rec, 1993 Oct 23;133(17):423-4.
    PMID: 8279113
    Matched MeSH terms: Haemonchiasis/veterinary*
  16. 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/veterinary*
  17. 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/veterinary*
  18. Genetic variation of Haemonchus contortus (Trichostrongylidae) in sheep and goats from Malaysia and Yemen
    Gharamah AA, Azizah MN, Rahman WA
    Vet Parasitol, 2012 Sep 10;188(3-4):268-76.
    PMID: 22538095 DOI: 10.1016/j.vetpar.2012.04.003
    The large stomach worm, Haemonchus contortus, commonly known as "the barber's pole worm", is a blood-sucking nematode found in the abomasa of sheep and goats. This work is the first documentation on the ND4 sequences of H. contortus from sheep and goats in Malaysia and Yemen and the results provide a preliminary insight on the genetic differences of H. contortus found in the two countries. In general, this study showed a high degree of diversity and low population structure of this species within the same country in comparison with higher genetic structuring at a wider geographical scale. The results also showed that the majority of genetic variance was within H. contortus populations. The Malaysian sheep and goat populations investigated appeared to share the same isolate of H. contortus while different isolates may be found in Yemen which must be taken into account in the design of an effective control strategy. Analysis of the internal transcribed spacer-2 (ITS-2) confirmed that all samples investigated in this study belonged to H. contortus. However presence of other Haemonchus species parasitizing these two hosts can only be confirmed by further detailed studies.
    Matched MeSH terms: Haemonchiasis/veterinary*
  19. An association of faecal egg counts and prolactin concentrations in sera of periparturient Angora goats
    Rahman WA, Collins GH
    Vet Parasitol, 1992 Jun;43(1-2):85-91.
    PMID: 1496805
    Faecal egg counts and serum prolactin concentrations in 13 pregnant and five non-pregnant Angora goats were monitored over a period of 20 weeks. The mean weekly egg counts of pregnant goats were significantly higher (P less than 0.01) than those of non-pregnant goats. In pregnant goats the mean egg counts in the 6 week post-partum period were significantly higher (P less than 0.01) than those of 6 weeks prepartum. The mean prolactin concentration of pregnant goats during the 6 week post-partum period was significantly higher (P less than 0.01) than that of 6 weeks pre-partum. During the 6 to 3 weeks before parturition, the prolactin values generally remained low (below 100 ng ml-1). The rise in prolactin concentration started between 3 weeks and 1 week before parturition. Only in pregnant goats was there a positive linear regression between prolactin levels and faecal egg counts.
    Matched MeSH terms: Haemonchiasis/veterinary
  20. 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/veterinary*
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