Hookworms in South Texas Coyotes and Bobcats

Abstract

Hookworm (Ancylostoma caninum) ova were found in 89.3 percent of the fecal samples of 75 coyotes (Canis latrans) and 97.7 percent of 44 bobcats (Lynx rufus) in the present South Texas study. Examination of field-collected scats of these two species showed 90.4 percent hookworm infestation in coyotes and 91.9 percent in bobcats. The degree of hookworm parasitism in these South Texas coyotes and bobcats, and the severity of hookworm infestations in many young host animals, suggest that hookworms could account for some of the natural mortality in wild populations of coyotes and bobcats. J. WILDL. MANAGE. 38(3):455-458 Hookworms occur in almost all suitable regions of their tropical and subtropical distribution (Miller 1971). These parasites are commonly found in dogs, cats, and other closely related carnivores. Hookworm infection is more severe in pups than adults, with the more visible characteristic symptoms being progressive anemia, emaciation, hemorrhagic diarrhea, and general weakness, sometimes resulting in death. The parasite's action is on the wall of the small intestine where it periodically attaches to suck blood and then releases to move to another site. A loss of blood ranging from 0.07 ml to 0.12 ml per worm per day occurs both from the hookworm's feeding and the abandoned oozing wound (Clark et al. 1961). Wells (1931), however, reported blood losses as high as 0.8 cc per worm per 24-hour period. Infection may occur by ingestion or cutaneous penetration (Morgan and Hawkins 1960:227), in utero by placental migration (Clapham 1962), or via the colostrum (Stone 1966). Hookworm infestations have been reported in populations of wild animals in several parts of North America. Olsen (1958) reported that hookworms (Uncinaria lucasi) were responsible for a rather high mortality of young fur seals (Callorhinus ursinus) on the Pribilof Islands. Hookworms have been reported in 33 percent of 66 coyotes sampled in Michigan (Dunatchik 1967), 25 percent of 1,850 Kansas coyotes (Gier and Ameel 1959), and 3.2 percent of 61 coyotes examined in Minnesota (Erickson 1944). Of 15 bobcats examined by Miller and Harkema (1968) in the Carolinas, 33 percent were infected with Ancylostoma caninum and 20 percent with A. braziliense. Little et al. (1971) found A. caninum in all seven bobcats checked from South Texas but in none of two West Texas bobcats. In general, the reported infestation rates per animal are relatively low but this is of little consequence since pregnant females acquiring light infestations can produce heavily infected young. The purpose of the present study was to establish the degree of hookworm infestation in wild populations of coyotes and bobcats in a portion of South Texas. This research was supported financially by the Caesar Kleberg Research Program in Wildlife Ecology through the Texas Agricultural Experiment Station, College Station, and the King Ranch, Inc. Thanks are extended to R. G. Sims, Field Assistant, U. S. Fish and Wildlife Service, for providing many of the animals used in the present study. B. A. Fall, Department of Wildlife and Fisheries J. Wildl. Manage. 38 (3):1974 455 This content downloaded from 207.46.13.168 on Sat, 09 Apr 2016 06:36:17 UTC All use subject to http://about.jstor.org/terms 456 HOOKWORMS IN COYOTES AND BOBCATS * Mitchell and Beasom Sciences, Texas AM R. B. Davis, Biology Department, Texas AM and J. P. Smith, Department of Veterinary Parasitology, Texas A&M University, are gratefully acknowledged for critically reading the manuscript.