Molecular delineation of Cylicocyclus nassatus and C. ashworthi (Nematoda: Strongylidae)

A survey in Louisiana of gastrointestinal helminths recovered at necropsy from 117 ponies with minimal exposure to anthelmintics between 1989 and 2000 is compared with a survey conducted 20 yr earlier in the same region. An objective of this study was to determine whether species diversity has been affected by the advent and use of the macrocyclic lactone (ML) parasiticides and by the increased anthelmintic pressure on the helminth species infecting the general equine population. Twenty-six cyathostome species and 8 strongyle species were recovered. Two cyathostome species that were not found before, Cylicostephanus asymetricus and C. bidentatus, and 1 species of large strongyle, Oesophagodontus robustus, were added to the list of species found in Louisiana. All cyathostome and large strongyle species found previously were still present. But prevalences and intensities were significantly reduced for almost all large and small strongyle species. Prevalences and intensities of Oxyuris equi adults and larvae...

Gastrointestinal helminths of ponies in louisiana: a comparison of species currently prevalent with those present 20 years ago

P-glycoproteins (Pgps) are adenosine triphosphate–binding transporter proteins thought to be associated with multidrug resistance in mammals and protozoans and have been suggested to be involved in the mechanism of ivermectin (IVM) resistance in Haemonchus contortus. Until now, resistance to IVM has not been reported in cyathostomins in horses in spite of its widespread and frequent use. Reasons for this might be differences in the molecular mechanism of the development of resistance. Based on this hypothesis, the present study was carried out to find homologues of Pgp in cyathostomins. A 416-bp polymerase chain reaction (PCR) product was generated using complementary DNA (cDNA) of Cylicocyclus elongatus and Cylicocyclus insigne and degenerate primers, located in the conserved Pgp nucleotide-binding domains. Resulting PCR products showed interspecific nucleotide and amino acid sequence identities of 73.3 and 76.8%, respectively. Specific primers were designed based on the Cc. elongatus sequence, and a PCR...

Evidence of p-glycoprotein sequence diversity in cyathostomins

Cylicocyclus asini n. sp. is described from the ventral colons of seven domesticated donkeys Equus asinus in South Africa. The specimens are smaller than 11 members of the genus Cylicocyclus, which currently comprises 10 recognised species, one recognised subspecies and two species inquirendae, but is similar in size to the two smaller species, C. ashworthi and C. leptostomum. Additionally, the small size of its buccal capsule places it within the so-called small buccal capsule group, namely C. ashworthi, C. leptostomum, C. nassatus, C. radiatus and C. triramosus. The shape of the oesophagus at the oesophago-intestinal junction is elongate, similar to that of C. leptostomum. The female specimens have a tail length shorter than the vulva to anus distance, similar to three of the smaller Cylicocyclus species, namely C. leptostomum, C. radiatus and C. triramosus. The new species is distinguished from the smaller members of the genus by the presence of a `club-foot' posterior in the female specimens, 40–46 elements in the external leaf-crown and a deep division of the dorsal ray which extends beyond the origin of the externodorsal ray. Similarly, the new species can be separated from the two other members in the genus with a `club-foot' posterior in the females (C. auriculatus and C. gyalocephaloides) by its body length (6.6–8.47 mm) and the presence of a nipple-like dorsal gutter.

Cylicocyclus asini n. sp. (Nematoda: Cyathostominae) from donkeys Equus asinus in South Africa.

Cyathostomins are ubiquitous nematodes of horses. Once ingested, they can spend a substantial time as encysted larvae in the intestinal wall. The larvae can comprise up to 90% of the total burden, with up to several million worms reported in individuals. These stages can emerge in large numbers to cause life-threatening colitis. Direct methods for detection of encysted larval burdens in live horses do not exist. Previously, two antigen complexes were identified as promising markers for infection. A component of these, cyathostomin gut associated larval antigen-1 (Cy-GALA-1), was identified following immunoscreening of a complementary DNA library. Serum immunoglobulin G(T) (IgG(T)) responses to Cy-GALA-1 were shown to inform on larval infection. Sequence analysis of polymerase chain reaction products amplified from individual worms indicated that Cy-GALA-1 was derived from Cyathostomum pateratum. As cyathostomin infections always comprise multiple species, a diagnostic test must account for this. Here, segments of the Cy-gala gene were isolated from four common species, Cyathostomum catinatum, Cylicocyclus ashworthi, Cylicostephanus goldi and Cylicostephanus longibursatus, and the associated proteins expressed in recombinant form. The specificity and immunogenicity of each protein was confirmed. Each protein was assessed by enzyme linked immuno sorbent assay (ELISA) for its ability for informing on the presence of encysted larval infection and the level of burden.

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ウマ(Equus caballus)のCylicocylus nassatusとCylicocylus ashworthi(線虫網:Cyathosominae)の顕微鏡的同定のための主要特徴