Studies into cytauxzoon and helminth infections of bobcats (Lynx rufus) of Northwest Arkansas

The purpose of this study was to determine the prevalence of Cytauxzoon felis and gastrointestinal helminth infections in bobcats (Lynx rufus) of Northwest Arkansas, an area known to have numerous cases of cytaux in domestic cats. Sixty bobcat carcasses were collected from trappers located in Mulberry and Decatur, Arkansas. Blood samples from the hearts were used to isolate Cytauxzoon DNA. Next, a polymerase chain reaction ( PCR) procedure coupled with gel-electrophoresis assay for the 18s region of extracted DNA were used to determine the presence of the protozoan in the bobcats at the time of harvest. Out of the 60 bobcats, 54 (90%) were positive for the protozoan’s infection. These findings indicate a large reservoir of Cytauxzoon for possible infection of domestic cats. Along with the detection of Cytauxzoon felis, intestinal helminths of the bobcats were collected and identified. The isolated helminths included Alaria marcianae, Ancylostoma sp., Molineus barbatus, Taenia sp., Spirometra mansonoides, Mesocestoides lineatus, Aonchotheca putorii, Physaloptera praeputialis and Toxocara cati. All helminths found were previously shown to be common in omnivorous and carnivorous sylvatic as well as domestic mammals of the region. It is amazing that bobcats are able to withstand both parasitic infections concurrently, as they roam the forests of Northwest Arkansas

Feasibility of Inducing Overlap Immunologic Competence in Gallinaceous Birds with Ascardia dissimilis and A. galli

Chickens and turkeys are routinely infected with the roundworms Ascaridia galli and A. dissimilis, respectively. The current study was conducted to gather basic information on these worms and to determine whether heterologous infections (chicken worms in turkeys and turkey worms in chickens) would be successful. Chickens and turkeys were obtained at day of hatch, brooded to 7 days of age, and placed in pens (25/pen) according to infection as received at 7 days of age: homologous, heterologous and control (no infection). Bird weights, mortalities, and feed efficiencies were monitored for 3 weeks postinfection, at which time all birds were killed for parasite collection and counting. Feed efficiency, a parameter more adequately measured in large-scale studies, did not vary between experimental groups. Bird weights at necropsy varied significantly (P \u3c 0.05) between groups only for the turkeys, with homologous infection (A. dissimilis) birds weighing less than controls. All induced, homologous, and heterologous infections were successful. Rates of establishment, however, were significantly (P \u3c 0.05) depressed for each heterologous model. Total A. dissimilis numbers were only 55% as great as those for A. galli in chickens [geometric means (GMs) of 13.2 versus 24.2], and total A. galli numbers were only 56% as great as A. dissimilis numbers in turkeys (GMs of 5.6 versus 10.0). Given the fact that heterologous infections were successful, albeit reduced, in both types of birds (infections that included tissue-phase forms), additional studies are planned to determine whether these infections might induce interspecies (overlapping) immune competence in the host and aid in reducing natural parasitisms to levels with no economic impact

Efficacies of fenbendazole and albendazole in the treatment of commercial turkeys artificially infected with Ascaridia dissimilis

The goal of this research was to determine the extent of resistance that turkey roundworms, Ascaridia dissimilis, have developed to anti-parasitic chemicals used in commercial poultry operations. Roundworm infections in turkeys have resulted in monetary losses for the poultry industry for years, generally due to poor feed conversion. The infection itself is subclinical and many turkeys have a light to moderate worm burden. Since parasitisms are light, this leads to the infections being noticed only during processing. Ascaridia dissimilis infections consist of adult worms and developing larvae with the latter comprising most of the worm burden and causing the most damage. In this study, eggs were collected from A. dissimilis found in turkeys previously treated with various parasiticides and combinations thereof. These eggs were in turn used to instill artificial infections in turkeys on site. These artificially infected turkeys were then treated with fenbendazole or albendazole. A third group of birds was left untreated as a control group. Drug efficacies were determined based on parasite loads post treatment (at necropsy). The results of this study will improve current knowledge of chemical resistance associated with these drugs

A survey into the prevalence of parasitic helminths in broiler breeders

A survey was conducted to determine the prevalence of helminth infections in spent broiler breeders. Intestinal tracts from 10 birds from each of five farms were obtained and examined for parasite identification and quantification. Heterakis gallinarum infections were the most common, followed in order of decreasing incidence by Capillaria obsignata, Ascaridia galli, and Raillietina cesticillus. Peak worm burdens for individual birds were 121 (A. galli), 535 (H. gallinarum), 215 (C. obsignata) and 125 (R. cesticillus). Significant farm-to-farm variation in worm burdens was observed

Preliminary results from a survey on the prevalence of parasitic helminths and protozoa in raccoons, opossums, and skunks

Raccoons, skunks, and opossums (N=57, 60, and 60, respectively) were necropsied for parasite detection and identification from September, 2001 until April, 2002. Qualitative coprological exams and adult Baylisascaris collections have been completed. Fecal stages and/or types found were Baylisascaris and Strongyloides-type (skunks and raccoons); Capillaria and Trichostrongyletype (raccoons and opossums); Acanthacephalan and ascarid type (opossums only); free larvae (skunks only); and coccidial (protozoan) oocysts (all three host species). Adult Baylisascaris were recovered from 33.3% of the raccoons and 58.3% of the skunks. Data collection relative to this survey, which is still ongoing, includes the determination of Sarcocystis prevalence in excised skunk and raccoon muscle as well as prevalence and magnitude of the numerous enteric helminths recovered from the three host animals

Acaricidal efficacy of various agents in the treatment of naturally occurring Ornithonyssus sylviarum (Acari: Macronyssidae) infestations of chickens

The northern fowl mite (NFM), Ornithonyssus sylviarum, is a commonly occurring external parasite of chickens. Primarily, caged layers have the greatest incidence of this mite, with bird unrest, unthriftiness and lowered production as some of the adverse effects of the infestation. In the current study, birds with natural NFM infestations were randomized into five treatment groups, placed in individual cages in treatment-specific batteries (all in one room), and evaluated for 28 d for infestation quantification by way of index scoring and feather digest. No treatments were 100% effective in eliminating all life stages of the mite. Tetrachlorvinphos in combination with dichlorvos (RAVAP E.C.® Boehringer Ingelheim) was the most effective with consistently negative post-treatment index scores and the greatest decrease in mite life stages (eggs, larvae, and nymphs/adults). Malathion dust (Hi-Yield® Voluntary Purchasing Groups, Inc.) and 10% garlic oil were next in level of effectiveness, with significant (P \u3c 0.05) post-treatment reductions in both index scores and mite life-stage populations. Permethrin (Permectrin II® Boehringer Ingelheim) provided the least control of the infestations, with no significant reductions in index scores and only slight reduction in the abundance of life stages after treatment

Investigating current efficacies of several nematocides for use in cattle according to the fecal egg count reduction test

Utilizing small groups of naturally infected replacement heifers, fecal egg count reduction tests (FECRT) were conducted in the later months of 2007 at the University of Arkansas Savoy Research Station. Each test was 28 d in length, consisting of individual fecal nematode egg counts (EPG) and coprocultures. For the first test, the calves were ranked by beginning EPG, blocked, and randomly assigned treatment within each block. Nine to ten animals were in each treatment group. In this test, neither IVOMEC (® Merial) or IVERMECTIN (® Durvet), both delivered as an injectable at the rate of 0.2 mg of ivermectin kg-1 BW, resulted in egg count reductions of ≥ 90%. Post-treatment coprocultures relative to both products contained a mixture of Cooperia and Haemonchus spp larvae. Also in this first test, Safe-Guard (® Intervet), delivered as a suspension at the rate of 5.0 mg of fenbendazole kg-1 BW, resulted in egg count reductions of 100% (d 7 and 14) and 88-87% (d 21 and 28). Posttreatment coprocultures specific to Safe-Guard yielded only Cooperia spp larvae. In the second test, which was of follow-up treatments given immediately after the first test (animals re-sorted to treatment group), Safe-Guard at the above rate resulted in egg count reductions of 99-100% (d 7 and 14) and 54-18% (d 21 and 28). Also in the second test, Cydectin (® Fort Dodge) treatment at the rate of 0.2 mg of moxidectin kg-1 BW resulted in egg count reductions of 96-92% (d 7 to 28) and SafeGuard treatment at the rate of 10 mg of fenbendazole kg-1 BW resulted in egg count reductions of 100-88% (d 7 to 28). As was the case in the first test, post-treatment coprocultures from animals treated with Safe-Guard yielded only Cooperia spp larvae. Treatment of cattle with Cydectin resulted in coprocultures that primarily yielded Cooperia, but with a trace of Haemonchus spp larvae

Contrasting patterns of isotype-1 β-tubulin allelic diversity in Haemonchus contortus and Haemonchus placei in the southern USA are consistent with a model of localised emergence of benzimidazole resistance

The benzimidazoles are one of the most important broad-spectrum anthelmintic drug classes for parasitic nematode control in domestic animals and humans. They have been widely used in livestock, particularly in small ruminants for over 40 years. This has resulted in widespread resistance in small ruminant gastrointestinal nematode parasite species, especially Haemonchus contortus. Benzimidazole resistance mutations have also been reported in Haemonchus placei, but only at low frequencies, suggesting resistance is at a much earlier stage of emergence than is the case for H. contortus. Here, we investigate the haplotype diversity of isotype-1 β-tubulin benzimidazole resistance mutations and the population genetic structure of H. contortus and H. placei populations from sheep and cattle from the southern USA. Microsatellite genotyping revealed a low level of genetic differentiation in six H.placei and seven H. contortus populations examined. This is consistent with several previous studies from other regions, mainly in H. contortus, supporting a model of high gene flow between parasite populations. There was a single F200Y(TAC) haplotype present in all six H. placei populations across Georgia, Florida and Arkansas. In contrast, there were at least two different F200Y(TAC) haplotypes (up to four) and two different F167Y(TAC) haplotypes across the seven H. contortus populations studied. These results provide further evidence to support a model for benzimidazole resistance in Haemonchus spp, in which resistance mutations arise from a single, or the small number of locations, in a region during the early phases of emergence, and subsequently spread due to animal movement