effects of time of day, season and stratum on haemonchus contortus and haemonchus placei third-stage larvae on irrigated pasture.the effect of time of day, season and stratum of herbage and soil on the availability of haemonchus contortus and haemonchus placei third-stage larvae (l3) on pasture was assessed. feces from infected calves and lambs were placed on pasture plots and samples of upper herbage, lower herbage, mat and soil were collected at five intervals per day throughout the daylight hours on 18 sample days over 12 months. using recovery rate factors derived from a preliminary investigation on the efficacy of la ...19911763493
characterization of a tandemly repetitive dna sequence from haemonchus contortus.genomic dna from the sheep parasitic nematode haemonchus contortus was shotgun cloned in the plasmid vector puc18. recombinants which gave the strongest hybridization signals to 32p-radiolabelled genomic dna were selected as representatives of the repetitive component of the parasite dna. one repetitive sequence which hybridized only with dna from h. contortus and not with dna from two other sheep nematodes (trichostrongylus colubriformis and ostertagia circumcincta) was further characterized by ...19948021102
seasonal prevalence of gastrointestinal nematode parasites of sheep in northern region of nile delta, egypt.over 1 year, from january to december 1999, a total of 173 slaughtered sheep at al-mahala abattoir were examined for presence of nematode parasites. eighteen sheep (10.4%) were infected with eight different species of nematodes. the prevalence rates of detected nematode parasites were; haemonchus contortus (3.5%), haemonchus placei (1.7%), trichuris ovis (5.8%), parabronema skrjabini (2.9%), ostertagia trifurcata (1.2%), chabertia ovina (0.6%) and strongyloides papillosus (0.6%), and graphidiops ...201020922430
protection against high-dose homologous infection in calves immunized with intestine or membrane extracts from haemonchus placei.control of haemonchus placei, one of the most important cattle nematodes in brazil, relies on the use of anthelmintics. however, there is a need for integrated control, which includes active immunization. the aim of this work was to assess the protection afforded to calves by immunization with adult h. placei extracts against a high-dose challenge infection, a condition frequently found in the tropics. holstein calves aged 8-10 months were immunized four times with intestinal extracts (group d) ...200818065148
host specificity of haemonchus spp. for domestic ruminants in the savanna in northern ivory coast.three haemonchus species (haemonchus contortus, haemonchus placei and haemonchus similis) live in sympatry in the savanna of north côte d'ivoire. four domestic ruminant hosts (zebu-cattle, taurine-cattle, sheep and goats) share the same pastures throughout the year. our post-mortem data imply that a haemonchus spp. circulation exists among the different hosts species in the savanna of north côte d'ivoire. under field conditions, mixed congeneric infections were the rule except in sheep where mon ...200314519319
experimental cross-infections of haemonchus placei (place, 1893) in sheep and examine effects on biology and morphology, haemonchus placei infections were propagated in cattle or sheep and infective larvae were introduced into the same or opposite host. ovine source larvae had a geometric mean (gm) prepatent period of 26.5 days regardless of host species, compared to 30.6 days for bovine source larvae regardless of host species. similarly, ovine source h. placei had a higher gm percentage establishment versus bovine source larvae (9.6% versus 3.4%) regardless of host s ...200111113549
a hybridisation technique to identify anthelmintic resistance genes in haemonchus.the identification of genes associated with anthelmintic resistance can be facilitated in haemonchus contortus by the ability of this species to hybridise with haemonchus placei. although the hybrid males are sterile, the lines can be rescued by backcrossing the females to either parental species. resistance genes can be retained in haemonchus hybrids, while the unwanted contortus background is removed through backcrossing to h. placei and anthelmintic selection of the progeny. under this select ...199910961854
description of haemonchus placei (place, 1893) (nematoda, trichostrongylidae, haemonchinae), identification and intra-specific morphologic variability.haemonchus placei in cattle has never been completely described, possibly due to great morphological similarity with small ruminants haemonchus contortus. it is newly described on one isolate from argentina. it has clear distinct morphological features from sheep and goats haemonchus contortus and presents only two female morphotypes (linguiform and knobbed) instead of three recorded in h. contortus. a key is proposed to identify females. female as well as male haemonchus placei from new world ( ...199910633504
host range and the maintenance of haemonchus spp. in an adverse arid climate.three haemonchus species (haemonchus contortus, haemonchus placei and haemonchus longistipes) live in sympatry in sahelian areas such as mauritania (west africa). four host species (dromedary, zebu cattle, sheep and goats) share the same pastures for several months per year. experimental infection by h. contortus or h. placei was achieved only poorly in dromedaries, and h. contortus or h. longistipes infection failed to establish in zebu cattle. conversely, h. placei and h. longistipes successfu ...19989512988
eprinomectin: a novel avermectin for use as a topical endectocide for cattle.eprinomectin (mk-397 or 4"-epi-acetylamino-4"-deoxy-avermectin b1) is a novel avermectin selected for development as a topical endectocide for all cattle, including lactating dairy cows. herein, we show its anthelmintic, insecticidal and miticidal activity. to determine its anthelmintic capabilities, eprinomectin was tested topically on jersey calves at 0.08, 0.2, or 0.5 mg kg-1 in a probe formulation against experimental infections of adult haemonchus placei, ostertagia ostertagi, trichostrongy ...19969024867
host movement and the genetic structure of populations of parasitic nematodes.mitochondrial dna (mtdna) sequence data were used to compare the population genetic structures of five species of parasitic nematodes from three different hosts: ostertagia ostertagi and haemonchus placei from cattle, h. contortus and teladorsagia circumcincta from sheep, and mazamastrongylus odocoilei from white-tailed deer. the parasites of sheep and cattle showed a pattern consistent with high gene flow among populations. the parasite of deer showed a pattern of substantial population subdivi ...19958582607
differentiation of haemonchus placei from h. contortus (nematoda: trichostrongylidae) by the ribosomal dna second internal transcribed spacer.there has been much debate as to whether h. placei is a separate species to h. contortus. the aim of this study is to provide molecular information to assess the species status of h. placei. using the polymerase chain reaction, the second internal transcribed spacer (its-2) of ribosomal dna was amplified and sequenced. comparison of the 231 base pair its-2 sequences showed no intraspecific variation in h. contortus, among one isolate from each of the united kingdom. switzerland and china and 5 i ...19957635624
cryopreservation of some common nematodes of ruminants for up to 11,3 years.infective larvae of selected batched of the following nematode species from sheep and cattle were examined for survival and infectivity (by injection into either the abomasum, the duodenum, or the jugular vein) after having been stored in liquid nitrogen for 103-136 months: haemonchus contortus, haemonchus placei, ostertagia circumcincta, ostertagia ostertagi, marshallagia marshalli, cooperia spp., trichostrongylus axei, trichostrongylus colubriformis, trichostrongylus falculatus, nematodirus sp ...19902338992
new morphological characters for identifying individual specimens of haemonchus spp. (nematoda: trichostrongyloidea) and a key to species in ruminants of north america.the large stomach worms haemonchus contortus, haemonchus placei, and haemonchus similis are important pathogens of cattle and sheep. this paper describes characteristics of surface cuticular ridges (synlophe), which for the first time provide morphological criteria for identifying individual adult specimens of either sex. the diagnostic patterns of the synlophe on the anterior half of specimens can be observed at 400x in temporary mounts on glass slides. the synlophe can be studied in cleared pr ...19948308643
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