Ecological, morphological and genetic characterization of sympatric Haemonchus spp. parasites of domestic ruminants in Mauritania

Abstract

The 4 species of ruminants (dromedary, zebu cattle, sheep and goat) in arid areas of Mauritania harboured Haemonchus spp. as the most frequent internal parasite. This was a rare situation where the 3 putative species, H. longistipes (dromedary), H. placei (zebu cattle) and H. contortus (sheep and goat) occurred sympatrically. The study was undertaken on hosts slaughtered at the Nouakchott abattoir, on the basis of monthly collection of worms. The environment was very unfavourable to H. placei and unfavourable to H. contortus, as intensity of infection remained low throughout the year, whereas infection in the dromedary was 10 to 20-fold higher. The survival strategies during the long, dry season were different: the surviving stages were either 4th-stage larvae in digesta (dromedaries), 4th-stage larvae either in digesta or mucosae (cattle), or 4th-stage larvae in mucosae and few adults (sheep and goats). The prolificacy of female worms, indicative of the potential to contaminate pastures, was similar for all Haemonchus spp. in the rainy season. H. longistipes behave differently during the pre-rainy season as no increase of prolificacy could be demonstrated as observed in the other species. Traits of vulvar morphology are considered as markers of ecological adaptation and were studied. The knobbed and smooth female morphs (in equal proportions) were the most frequent in H. longistipes, the knobbed morph out-numbered the other morphs in H. placei, and all 3 morphs were present in sheep and goats with the linguiform form being predominant. Genetic characterization of the 3 species was performed by means of Random Amplified Polymorphic DNA (RAPD). Three groups were obtained from analysis of these data: 1 group with individuals of H. contortus, 1 group with individuals of H. placei, and 1 group with individuals of H. longistipes. This indicated that, although the 3 species were valid, H. contortus and H. placei were more similar. Intraspecific variability was 2-fold higher in H. contortus than in the 2 other species. The ecological, morphological and genetical studies showed that H. longistipes, H. placei and H. contortus could be arranged in increasing order of variability.

An abattoir-based study on helminthes of slaughtered goats (Capra hircus L., 1758) in upper Egypt, Egypt

“…in goats (15.5 %) suggesting that small ruminants are most susceptible and usual host of H. contortus than H. longistipes. This result supports the work of Achi et al (2003), Gelaye & Abebe (2001), Jacutet et al (1992, 1995, Thomas et al (2007) all of which reported the dominance of H. contortus in small ruminants. Additionally, the present study also imply that goats could also host H. longistipes, which was reported for the first time infecting goats at upper Egypt region; and it is in agreement with previous studies conducted by Jacutet et al (1992).…”

“…Regarding to Haemonchus species identification were performed according to descriptions of Jacquiet (1995). Data were presented in tables.…”

Abomasal nematodes of sheep and goats slaughtered in Awassa (Ethiopia): species composition, prevalence and vulvar morphology

“…Tod (1965) also considered that vulvar morphology is a manifestation of some genetic factors important to establish and develop in hosts. Vulvar morphology is also considered as markers of ecological adaptation to an area (Rose, 1966;Le Jambre & Whitlock, 1968;Jacquiet, 1995). These investigators described that, based on vulvar morphology, it is possible to arrange Haemonchus spp.…”

Phylogeny for Species of Haemonchus (Nematoda: Trichostrongyloidea): Considerations of Their Evolutionary History and Global Biogeography Among Camelidae and Pecora (Artiodactyla)

“…Haemonchus represent the most economically important helminth parasites in cattle, sheep, and goats throughout the world (Gibbs and Herd, 1986), and considerable research has been conducted on those species, H. contortus (Rudolphi, 1803), H. placei (Place, 1893), and H. similis, Travassos, 1914, that are globally distributed in domesticated Bovinae and Caprinae. Another 7 species, H. bedfordi Le Roux, 1929, H. dinniki Sachs, Gibbons and Lweno, 1973, H. horaki Lichtenfels, Pilitt, Gibbons and Boomker, 2001, H. krugeri Ortlepp, 1964, H. lawrencei Sandground, 1933, H. mitchelli Le Roux, 1929, and H. vegliai Le Roux, 1929, are primary parasites among respective host groups and species of wild Bovinae, Cephalophinae, Reduncinae, Aepycerotinae, Antilopinae, Alcelaphinae, and Caprinae in sub-Saharan Africa, whereas H. okapiae van den Berghe, 1937 occurs in Giraffidae, and H. longistipes Railliet and Henry, 1909 occurs in Camelidae and domestic sheep, goats, and rarely, cattle across a broader range extending from Africa to southern Eurasia (Gibbons, 1979;Jacquiet et al, 1995;Lichtenfels et al, 2001Lichtenfels et al, , 2002. Although as a group these nematodes have been the focus of considerable taxonomic study, there has been no previous attempt to elucidate phylogenetic relationships among the recognized species of Haemonchus (e.g., Almeida, 1935;Gibbons, 1979).…”