The Wandering of Haemonchus in the Sheep Host

Stoll, Norman R.

doi:10.2307/3272850

Cited by 19 publications

(6 citation statements)

References 8 publications

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“…The progressive developmental stages conformed to those found by other workers (VEGLIA, 1915;ANDREWS, 1942;SILVERMAN & PATTERSON, 1960). While the specific timing of the larval development stages differ from the findings of others (VIXILIA, 1915;STOLL, 1943;CHARLESTON, 1965) they correspond to the results for susceptible lambs described by SILVERMAN & PATTERSON, 1960, reflecting the age of the lambs challenged and their immunological status and competency.…”

Section: Discussionsupporting

confidence: 87%

“…Since the initial description of the life-cycle by RANSOM (1906) and the additional precise studies of the anatomy of the various developmental stages by VEGLIA (1915) much information on Haemonchus contortus has been published. In general, however, this has reflected aspects of parasitology, of the epidemiology of the disease in sheep, and of the nature of the ensuing anaemia, with only brief references to the pathological effects (Foirnin, 1931;ANDREWS, 1942;STOLL, 1943;MISRA & RUPRAH, 1972). The histological changes at various time intervals in susceptible and resistant sheep were reported by SILVERMAN & PATTERSON (1960) in their studies of the histiotrophic stages of //.…”

Section: Introductionmentioning

confidence: 99%

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The pathogenesis of a single challenge dose ofHaemonchus contortusin lambs under six months of age

Hunter

Mackenzie

1982

J. Helminthol.

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The pathogenesis of H. contortus infection in lambs under 6 months of age challenged orally with 10,000 third stage infective larvae is described. The development of the parasite and its relationship to haematological and pathological changes are discussed, with particular reference to specific cellular mobilizations, and detailed descriptions are given of the haematology and parasitology, gross pathology and histopathology at 4, 7, 12, 18, 22 and 35 days after infection. Dramatic changes had developed by day 12.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

The pathogenesis of a single challenge dose ofHaemonchus contortusin lambs under six months of age

Hunter

Mackenzie

1982

J. Helminthol.

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“…The very fecund female H . contortus lay 5,000–10,000 eggs per day, beginning after 12–15 days, although this is variable [ 38 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

The bacterial community associated with the sheep gastrointestinal nematode parasite Haemonchus contortus

et al. 2018

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Culture-independent methods were used to study the microbiota of adult worms, third-stage larvae and eggs, both in faeces and laid in vitro, of Haemonchus contortus, a nematode parasite of the abomasa of ruminants which is a major cause of production losses and ill-health. Bacteria were identified in eggs, the female reproductive tract and the gut of adult and third-stage larvae (L3). PCR amplification of 16S rRNA sequences, denaturing gradient gel electrophoresis (DGGE) and clone libraries were used to compare the composition of the microbial communities of the different life-cycle stages of the parasites, as well as parasites and their natural environments. The microbiomes of adult worms and L3 were different from those in the abomasum or faeces respectively. The H. contortus microbiota was mainly comprised of members of the phyla Proteobacteria, Firmicutes and Bacteroidetes. Bacteria were localised in the gut, inside eggs and within the uterus of adult female worms using the universal FISH Eub338 probe, which targets most bacteria, and were also seen in these tissues by light and transmission electron microscopy. Streptococcus/Lactococcus sp. were identified within the distal uterus with the probe Strc493. Sequences from the genera Weissella and Leuconostoc were found in all life-cycle stages, except eggs collected from faeces, in which most sequences belonged to Clostridium sp. Bacteria affiliated with Weissella/Leuconostoc were identified in both PCR-DGGE short sequences and clone libraries of nearly full length 16S rRNA bacterial sequences in all life-cycle stages and subsequently visualised in eggs by fluorescent in situ hybridisation (FISH) with group-specific probes. This strongly suggests they are vertically transmitted endosymbionts. As this study was carried out on a parasite strain which has been maintained in the laboratory, other field isolates will need to be examined to establish whether these bacteria are more widely dispersed and have potential as targets to control H. contortus infections.

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“…Following exsheathment, L3s undergo a short histotropic phase in the stomach mucosa [ 82 ] and then develop to haematophagous stages (L4s and adults) [ 80 ]. This development is reflected in a range of morphological changes in both male and female worms, including the formation of a buccal capsule in both sexes, bursal rays and spicules in the male, and development of vulva and other reproductive organs in the female.…”

Section: Discussionmentioning

confidence: 99%

The Haemonchus contortus kinome - a resource for fundamental molecular investigations and drug discovery

et al. 2015

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BackgroundProtein kinases regulate a plethora of essential signalling and other biological pathways in all eukaryotic organisms, but very little is known about them in most parasitic nematodes.MethodsHere, we defined, for the first time, the entire complement of protein kinases (kinome) encoded in the barber’s pole worm (Haemonchus contortus) through an integrated analysis of transcriptomic and genomic datasets using an advanced bioinformatic workflow.ResultsWe identified, curated and classified 432 kinases representing ten groups, 103 distinct families and 98 subfamilies. A comparison of the kinomes of H. contortus and Caenorhabditis elegans (a related, free-living nematode) revealed considerable variation in the numbers of casein kinases, tyrosine kinases and Ca2+/calmodulin-dependent protein kinases, which likely relate to differences in biology, habitat and life cycle between these worms. Moreover, a suite of kinase genes was selectively transcribed in particular developmental stages of H. contortus, indicating central roles in developmental and reproductive processes. In addition, using a ranking system, drug targets (n = 13) and associated small-molecule effectors (n = 1517) were inferred.ConclusionsThe H. contortus kinome will provide a useful resource for fundamental investigations of kinases and signalling pathways in this nematode, and should assist future anthelmintic discovery efforts; this is particularly important, given current drug resistance problems in parasitic nematodes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1231-5) contains supplementary material, which is available to authorized users.

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The Wandering of Haemonchus in the Sheep Host

Cited by 19 publications

References 8 publications

The pathogenesis of a single challenge dose ofHaemonchus contortusin lambs under six months of age

The pathogenesis of a single challenge dose ofHaemonchus contortusin lambs under six months of age

The bacterial community associated with the sheep gastrointestinal nematode parasite Haemonchus contortus

The Haemonchus contortus kinome - a resource for fundamental molecular investigations and drug discovery

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