PREVALENCE OF STRONGYLE NEMATODES IN NATURALLY INFECTED PONIES OF DIFFERENT AGES AND DURING DIFFERENT SEASONS OF THE YEAR IN LOUISIANA

One hundred and seventeen ponies were surveyed for the seasonal prevalence of strongyloid parasites, particularly cyathostomes, and for host- and age-related differences in these infections. For 56 ponies, all stages of the cyathostome life cycle, both mucosal and luminal, were enumerated. Total numbers of cyathostomes and percentage of developing larvae (DL) encysted in the mucosa remained constant in all 4 seasons of the year, whereas a significant increase in the percentage of adults in the cyathostome population occurred in fall. In yearling ponies, encysted early third-stage larvae constituted a significantly lower percentage of the cyathostome population, and DL and adults formed a significantly higher percentage, compared with those stages in older ponies, 2–5 yr of age. More species of cyathostomes were present in yearling ponies than in older ponies. Significant differences occurred in fecal egg counts at different seasons of the year, even though adult cyathostome and large strongyle numbers remained constant. Twenty-four species of cyathostomes were found year-round, and 2 rare species were found in only 2 or 3 seasons of the year. Prevalences for these 24 species were not significantly different during any season, although 5 species had significant differences in intensity levels of infection in certain seasons of the year. Three species of large strongyle (strongylinae) adults had significant seasonal variations in intensities. These were Strongylus edentatus and S. vulgaris, which occurred in significantly higher numbers in summer and fall, and Triodontophorus brevicauda, which was more numerous in spring and summer. Fourth- and fifth-stage larvae of S. vulgaris recovered from the mesenteric vasculature were significantly more numerous in winter and spring than in other seasons.

[1]  D. French,et al.  GASTROINTESTINAL HELMINTHS OF PONIES IN LOUISIANA: A COMPARISON OF SPECIES CURRENTLY PREVALENT WITH THOSE PRESENT 20 YEARS AGO , 2002, The Journal of parasitology.

[2]  H. W. Taylor,et al.  ONE SEASON OF PASTURE EXPOSURE FAILS TO INDUCE A PROTECTIVE RESISTANCE TO CYATHOSTOMES BUT INCREASES NUMBERS OF HYPOBIOTIC THIRD-STAGE LARVAE , 2002, The Journal of parasitology.

[3]  D. French,et al.  SEASONAL TRANSMISSION OF GASTROINTESTINAL PARASITES OF EQUIDS IN SOUTHERN LOUISIANA , 2001, The Journal of parasitology.

[4]  J. Matthews,et al.  Nematodes of the tribe cyathostominea (Strongylidae) collected from horses in Scotland , 2001 .

[5]  T. Klei Equine immunity to parasites. , 2000, The Veterinary clinics of North America. Equine practice.

[6]  D. French,et al.  Seasonal development and survival of equine cyathostome larvae on pasture in south Louisiana. , 2000, Veterinary parasitology.

[7]  M. Kearney,et al.  An experimental evaluation of methods used to enumerate mucosal cyathostome larvae in ponies. , 1999, Veterinary parasitology.

[8]  T. Klei,et al.  Immunity in equine cyathostome infections. , 1999, Veterinary parasitology.

[9]  T. Craig Considerations for the control of equine cyathostomes in arid areas. , 1999, Veterinary parasitology.

[10]  C. H. Courtney Seasonal transmission of equine cyathostomes in warm climates. , 1999, Veterinary parasitology.

[11]  D. Mellor,et al.  Pathogenicity of cyathostome infection. , 1999, Veterinary parasitology.

[12]  C. Reinemeyer Current concerns about control programs in temperate climates. , 1999, Veterinary parasitology.

[13]  R. Krecek,et al.  An annotated checklist by genus and species of 93 species level names for 51 recognized species of small strongyles (Nematoda: Strongyloidea: Cyathostominea) of horses, asses and zebras of the world. , 1998, Veterinary parasitology.

[14]  H. W. Taylor,et al.  Experimental cyathostome challenge of ponies maintained with or without benefit of daily pyrantel tartrate feed additive: comparison of parasite burdens, immunity and colonic pathology. , 1998, Veterinary parasitology.

[15]  S. S. Collins,et al.  Transmission of some species of internal parasites in horses born in 1993, 1994, and 1995 on the same pasture on a farm in central Kentucky. , 1997, Veterinary parasitology.

[16]  R. Gasser,et al.  The prevalence and epidemiology of gastrointestinal parasites of horses in Victoria, Australia. , 1995, International journal for parasitology.

[17]  T. Mair Outbreak of larval cyathostomiasis among a group of yearling and two-year-old horses , 1994, Veterinary Record.

[18]  J. R. Mcclure,et al.  Production and characterization of monospecific adult worm infections of Strongylus vulgaris and Strongylus edentatus in ponies. , 1994, Veterinary parasitology.

[19]  M. W. Mfitilodze,et al.  Prevalence and abundance of equine strongyles (Nematoda: Strongyloidea) in tropical Australia. , 1990, The Journal of parasitology.

[20]  M. Eysker,et al.  Seasonally inhibited development of cyathostomine nematodes in Shetland ponies in The Netherlands. , 1990, Veterinary parasitology.

[21]  I. Horak,et al.  Internal parasites of horses on mixed grassveld and bushveld in Transvaal, Republic of South Africa. , 1989, Veterinary parasitology.

[22]  M. W. Mfitilodze,et al.  Prevalence and intensity of non-strongyle intestinal parasites of horses in northern Queensland. , 1989, Australian veterinary journal.

[23]  J. Valenzuela,et al.  Epidemiology of strongyles in ponies in Ontario. , 1987, Canadian journal of veterinary research = Revue canadienne de recherche veterinaire.

[24]  J. Williams,et al.  The epidemiology of Ostertagia ostertagi and other gastrointestinal nematodes of cattle in Louisiana , 1987, Parasitology.

[25]  J. R. Lichtenfels,et al.  A survey in Louisiana of intestinal helminths of ponies with little exposure to anthelmintics. , 1986, The Journal of parasitology.

[26]  T. Wensing,et al.  Comparison of two control systems for cyathostome infections in the horse and further aspects of the epidemiology of these infections. , 1986, Veterinary parasitology.

[27]  R. Herd,et al.  Observations on the population dynamics of five cyathostome nematode species of horses in northern USA. , 1986, Equine veterinary journal.

[28]  G. W. Hutchinson,et al.  The site distribution of adult strongyle parasites in the large intestines of horses in tropical Australia. , 1985, International journal for parasitology.

[29]  J. Dunsmore,et al.  Prevalence and epidemiology of the major gastrointestinal parasites of horses in Perth, Western Australia. , 1985, Equine veterinary journal.

[30]  R. Herd,et al.  The prevalence and intensity of internal parasites of horses in the U.S.A. , 1984, Veterinary parasitology.

[31]  Craig Tm,et al.  Transmission of equine cyathostomes (Strongylidae) in central Texas. , 1983 .

[32]  J. Bowen,et al.  Transmission of equine cyathostomes (Strongylidae) in central Texas. , 1983, American journal of veterinary research.

[33]  T. Klei,et al.  Efficacy of ivermectin (22,23-dihydroavermectin B1) against gastrointestinal parasites in ponies. , 1980, American journal of veterinary research.

[34]  A. English The epidemiology of equine strongylosis in southern Queensland. 3. Seasonal variation in arterial populations of Strongylus vulgaris, and the prevalence of some helminths. , 1979, Australian veterinary journal.

[35]  C. Ogbourne The prevalence, relative abundance and site distribution of nematodes of the subfamily Cyathostominae in horses killed in Britain , 1976, Journal of Helminthology.

[36]  C. Ogbourne Epidemiological studies on horses infected with nematodes of the family Trichonematidae (Witenberg, 1925). , 1975, International journal for parasitology.

[37]  A. O. Foster A RELATIONSHIP IN EQUINES BETWEEN AGE OF HOST AND NUMBER OF STRONGYLID PARASITES , 1937 .