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Biomedical subjects

C R Reinemeyer

Publications and source records attributed to C R Reinemeyer.

At least 19 recordsLinked to original sources

Efficacy of moxidectin equine oral gel against endoscopically-confirmed Gasterophilus nasalis and Gasterophilus intestinalis (Diptera: Oestridae) infections in horses.

A 3 m, video gastroscope was used to screen 47 horses suspected of being naturally infected with equine bot larvae. 17 of 47 (36.2%) candidate horses harbored Gasterophilus nasalis larvae in the proximal duodenum and 46 of 47 (97.9%) had G. intestinalis larvae in the stomach. All horses infected with G. nasalis had concurrent infections with G. intestinalis. 14 horses with dual infections were allocated randomly to two treatment groups. Seven horses in Group 1 received 2% moxidectin oral gel once at a dosage of 0.4 mg/kg bodyweight (BW), and seven horses in Group 2 were untreated controls. 14 days after treatment, all horses were necropsied and the stomach and proximal duodenum harvested from each. Bot larvae were recovered, identified to species and instar, and counted. At the label dosage, moxidectin oral gel was 100 and 97.6% effective (P < 0.05) against third-instar G. nasalis and G. intestinalis, respectively. In addition to demonstrating the boticidal efficacy of moxidectin, this trial illustrated that gastroscopy/duodenoscopy is a feasible method for confirming infections with different species of bot larvae in the horse.

Administration, Oral↗

Current concerns about control programs in temperate climates.

Efforts to control cyathostome nematodes in temperate climates have not been uniformly successful, as evidenced by contemporary reports of clinical disease and widespread anthelmintic failure. Indeed, effective control is confounded by numerous factors, including ignorance of local transmission patterns, confusing or conflicting control recommendations, and use of ineffective anthelmintics or regimens. Most of these problems are universal rather than being climatically unique, and it is important to recognize that they are mere symptoms of larger and more comprehensive problems. The most basic problem in managing cyathostomes is inadequate knowledge of biological factors that influence control recommendations. These include population dynamics, arrested development, host resistance, and regional bionomics. Another hindrance is the absence of objective criteria to define effective control. Target fecal egg counts are arbitrary and subjective, and parameters to measure the subclinical impact of cyathostome infection in well-managed horses have not been identified. The final general challenge to effective parasite control is motivation and education of equine practitioners and horse owners, who currently receive much of their parasite control information in the form of biased advertising. Ultimately, more effective equine parasite control will result from collaborative efforts of basic research, clinical application, and improved information transfer.

Animals↗

Results of a survey to assess knowledge and expectations of veterinarians and their clients regarding heartworm preventives and vaccinations in dogs.

OBJECTIVE: To determine the knowledge and expectations of veterinarians and clients regarding heartworm preventives and annual vaccinations for dogs. DESIGN: Practitioner and client survey. SAMPLE POPULATION: 435 veterinarians and 1,805 clients. PROCEDURE: A survey was mailed to veterinarians requesting information from them and their dog-owning clients on expectations and knowledge regarding heartworm preventives and annual vaccinations. Responses of veterinarians were compared with those of clients, and both were compared with label indications. RESULTS: Expectations of veterinarians and clients regarding heartworm preventives were similar and usually were consistent with regulatory interpretation of label terms. Of clients purchasing heartworm preventives, 38% did not know that the medication was effective against intestinal nematodes. Veterinarians and clients would be unsatisfied with a product that reduced, but did not eliminate, all intestinal nematodes. Most clients knew that annual vaccinations included distemper virus, parvovirus, and rabies virus, but about half of them did not know that other antigens were in the vaccines. CLINICAL IMPLICATIONS: Effects of heartworm preventives and diseases for which dogs are annually vaccinated should be explained fully to clients.

Animals↗

Comparison of the efficacies of three heartworm preventives against experimentally induced infections with Ancylostoma caninum and Toxocara canis in pups.

Forty 11- to 12-week-old helminth-naive Beagles were categorized by sex and weight and randomly assigned to 4 treatment groups (group 1, ivermectin/pyrantel pamoate; group 2, milbemycin oxime; group 3, untreated control; group 4, diethylcarbamazine/oxibendazole). Each pup was inoculated PO with approximately 100 infective Ancylostoma caninum larvae and 100 larvated Toxocara canis eggs on day 0, and repeatedly at 7-day intervals thereafter until day 56. Administration of anthelmintics also began on day 0, and subsequent treatments were administered according to label recommendations at 30-day intervals (groups 1 and 2) or daily (group 4) for a period of 90 consecutive days. Body weight and A caninum and T canis fecal egg counts were measured at weekly intervals, and clinical observations of health status were conducted twice daily. Pups were euthanatized on day 90, and total gastrointestinal worm burdens were determined. Compared with mean A caninum egg counts of group-3 control pups, egg counts in group-1 pups were significantly (P < or = 0.0001) lower on every sampling days 35, 42, 49, 63, 70, 77, and 84, and were consistently the highest of all treated groups, and egg counts of group-4 pups were significantly (P < or = 0.0001) lower on every sampling date from day 14 to day 90, and were consistently the lowest of all treated groups. Compared with mean A caninum egg counts of group-3 pups, egg counts in group-1 and group-2 pups were lower by 97.8 and 90.8%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Effects of housing and colostrum feeding on serum immunoglobulins, growth, and fecal scores of Jersey calves.

Ninety-six Jersey calves were used to evaluate the effects of housing and method of colostrum feeding on serum Ig concentrations, incidence and severity of scours, intake, and BW changes from birth to 35 d of age. Calves were separated from the dam and fed 2 L of colostrum in nipple-bottles or allowed to nurse the dam for 3 d. Calves were housed in individual hutches or wooden pens in a barn. Intake of colostrum by calves allowed to nurse the dam was not controlled. Serum IgG and IgM concentrations at 24 h of age were greater for calves that nursed the dam. Scours were less severe when calves were housed in hutches, but number of days scouring was unaffected by treatment. Calves fed colostrum in nipple-bottles and housed in the barn consumed more starter than did other calves from 3 to 5 wk of age. The BW were greater for calves allowed to nurse the dam and housed in hutches. Feed efficiency over the 35-d study was improved when calves nursed the dam. Optimal transfer of passive immunity and housing in hutches appeared to maximize health and growth in this study.

Animal Nutritional Physiological Phenomena↗

Effects of housing and colostrum feeding on the prevalence of selected infectious organisms in feces of Jersey calves.

Neonatal Jersey calves (n = 96) were used to evaluate effects of housing (individual hutches or wooden pens in a barn) and colostrum feeding (calves were separated from the dam and fed 2 L of colostrum in nipple-bottles or allowed to nurse the dam for 3 d) on the prevalence of selected organisms in feces. Prevalence of Cryptosporidium and Eimeria were reduced, and prevalence of rotavirus tended to be reduced, when calves were housed in hutches. Prevalence of coronavirus was unaffected by treatment. Weekly prevalence of Giardia was increased when calves were left to nurse the dam for 3 d. Mean prevalence of Cryptosporidia (wk 1 to 4), Eimeria (wk 4 to 5), Giardia, rotavirus, and coronavirus (wk 1 to 5) were 34.7, 20.6, 27.1, 15.8, and 4.9%, respectively. Escherichia coli (K99 positive) were observed in 3 of 174 samples cultured. Methods of housing and colostrum feeding affected acquisition of enteropathogens in this study.

Animals↗

Effects of lasalocid on coccidial infection and growth in young dairy calves.

Effects of lasalocid on coccidial infection and on calf growth were examined in 16 Holstein bull calves. Calves were assigned randomly to a 2 x 2 factorial arrangement of starter ration containing 0 or 40 mg of lasalocid/kg of starter, beginning when calves were 3 days old (SE = 0.046), and single oral inoculation with 0 or 30,000 sporulated oocysts (Eimeria bovis) at 28 days. Pelleted calf starter was fed ad libitum from day 1; milk replacer was fed at a rate of 3.6 kg/d until day 28. Mean daily gain, dry-matter intake, and body weight were increased in calves fed lasalocid and decreased in those inoculated with coccidia. Addition of lasalocid to the feed improved gains by 8% in uninoculated calves and by 50% in inoculated calves. Fecal oocyst numbers were reduced when lasalocid was fed to inoculated calves. Feces were more abnormal in calves inoculated with coccidia. Respiration rates, rectal temperatures, PCV, and serum sodium and potassium concentrations were unaffected by treatment. On the basis of findings in this study, lasalocid minimized effects of coccidial challenge inoculation and increased growth of calves.

Animal Feed↗

A survey of ovine parasite control practices in Tennessee.

A sample of 126 sheep producers in Tennessee was randomly selected from the members of a statewide organization of sheep producers. Data about the participants' farms, sheep, parasite control practices and sources of information regarding ovine parasite control were obtained by a telephone survey. The response rate was 99%. The typical respondent kept 20 lambs, 20 ewes and 2 rams on three pastures totalling 20 acres. In order of decreasing frequency, anthelmintics were given according to a regular schedule, to coincide with breeding management procedures, or to treat clinical signs of parasitism. Proportions of producers deworming the various classes of sheep zero, one, two, three, four or more than four times annually were as follows: lambs--3, 28, 40, 16, 9 and 8%, respectively; ewes--3, 8, 20, 16, 34 and 22%, respectively; rams--1, 9, 19, 15, 38 and 19%, respectively. The majority of respondents planned to deworm lambs (89%) and ewes (82%) the same number of times in the following year. Of the producers who dewormed sheep two or more times during 1989, 39-49% (ranges include different proportions for lambs, ewes and rams) used the same anthelmintic exclusively, and 51-61% used two or more drug classes. Of the owners using a single anthelmintic exclusively, most (39-66%) used ivermectin, followed by levamisole (19-33%) and benzimidazoles (13-24%). One hundred and three of 124 (83%) producers intended to use the same anthelmintics in the future. Sixty-four of 124 (52%) producers had discontinued using at least one ovine anthelmintic. The most common reasons for discontinuance were dissatisfaction with the clinical response after treatment and inconvenience of administration. Sheep-oriented publications, other sheep producers and veterinarians were considered the most important sources of information about deworming programs and choice of anthelmintics.

Animals↗

A survey of equine parasite control practices in Tennessee.

A weighted, random sample of 130 horse owners in Tennessee was selected from subscribers to an equine newsletter published by the Agricultural Extension Service. Data about the participants' farms, horses, parasite control practices, and sources of information regarding equine parasite control were obtained through a telephone survey. The response rate was 98%. The typical respondent kept 4 horses on 2 pastures totaling 15 acres, and did not rotate pastures as a parasite control measure. The majority (83%) of horse owners indicated that they administered anthelmintics according to a regular schedule; 9% delayed deworming until the onset of weight loss. Proportions of owners deworming the various classes of horses at least 1, 2, 3, or 4 times annually were as follows: foals (0 to 6 months) 100, 60, 15, and 0%, respectively; weanlings (6 to 12 months) 100, 91, 32, and 0%, respectively; yearlings (1 to 2 years) 100, 100, 86, and 51%, respectively; and adults (greater than 2 years) 100, 94, 56, and 24%, respectively. Median treatments of yearlings and adults were evenly spaced at 6-, 4-, or 3-month intervals when the owners dewormed 2, 3, or 4 times annually, respectively. Mean intervals between treatments of foals and weanlings were less regular. Of the horse owners who dewormed 2 or more times annually, most (53 to 80%) used the same product exclusively for all treatments. In all age classes of horses, ivermectin paste (46 to 63%) was the most common product used, followed by tube deworming (23 to 38%) and use of benzimidazoles (4 to 16%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Evaluation of the efficacy and safety of two formulations of pyrantel pamoate in cats.

The efficacy of paste and granule formulations of pyrantel pamoate against concurrent infections of Toxocara cati and Ancylostoma tubaeforme in cats was examined in a controlled trial. Three groups of 8 cats received either no medication (controls) or pyrantel pamoate in paste or granule formulations at a dosage of 20 mg/kg of body weight. After administration of the paste formulation, fecal egg counts of A tubaeforme and T cati were decreased by 98.6 and 96.4%, respectively, and 100% of hookworms and 93.5% of ascarids were removed from the intestine. After administration of the granule formulation, fecal egg counts of A tubaeforme and T cati were decreased by 99.4 and 78.2%, respectively, and 100% of adult hookworms and 88.9% of ascarids were removed. All reductions of egg counts and worm numbers were significant (P less than 0.01). The clinical safety of pyrantel pamoate was evaluated in 4- to 6-week-old kittens. Three groups of 10 kittens received either no medication (controls) or pyrantel pamoate in paste or granule formulations at the rate of 100 mg/kg for 3 consecutive days. Adverse effects were not observed in young kittens following administration of the high dose of pyrantel pamoate.

Administration, Oral↗

Fatal lungworm infection in an opossum.

A 3-mo-old male, feral opossum (Didelphis virginiana) was presented to the University of Tennessee College of Veterinary Medicine (USA) for evaluation of prolonged dyspnea. The animal died shortly after examination and a necropsy was performed. The cause of death was attributed to a verminous pneumonia, associated with numerous intrabronchial and intrabronchiolar nematodes, subsequently identified as Didelphostrongylus hayesi.

Animals↗

Control of gastrointestinal nematodes in dairy heifers by two strategic treatments with ivermectin.

Dairy replacement heifers given two strategic treatments with ivermectin (0.2 mg/kg) three and eight weeks after turnout to spring pastures in northern USA had mean adjusted weight gains (62.3 kg) that were 62 per cent (P less than 0.02) greater than those of control heifers (38.5 kg) at the time of winter housing. Pasture infectivity was consistently higher in control pastures and there was a sixfold difference between treatment (56 L3/kg) and control (358 L3/kg) pastures by the time of winter housing on October 18. This study confirmed earlier studies in northern USA demonstrating the value of two strategic treatments in achieving significant increases in weight gains and hastening the time of first breeding by one to three months at a saving of $40 to $140 per heifer. It was concluded that this dosing strategy is a satisfactory method of parasite control for dairy replacement heifers in northern USA without undue selection for drug resistance.

Analysis of Variance↗

Small strongyles. Recent advances.

The recent increased interest in cyathostomes can be traced to simplification of their taxonomy, improved knowledge of pathogenicity, and failures of practical control due to anthelmintic resistance. Cyathostome ova develop to infective third-stage larvae (L3) at a rate that is directly proportional to environmental temperature. Equine feces serve as a reservoir for L3, which are liberated by moderate amounts of rainfall. Third-stage larvae persist for longer periods at low temperatures, easily surviving over-winter on pastures to provide a source of infection during the following grazing season. Third-stage larvae exsheath within the host and enter the mucosa and submucosa of the cecum and large colon. Larvae develop within mucosal cysts, molt to the fourth stage, and may persist within the tissues for up to 2 1/2 years. Larvae ultimately emerge from the mucosa to become adults in the lumen. Adult populations are replenished by recently ingested larvae and by immature worms newly emerged from arrested development. The magnitude of larval and adult populations within the host displays seasonal variations, with peak numbers occurring in early spring and autumn in the United States. In typical natural infections, a small number of species comprise the majority of the cyathostome populations. Cyathostome infection may result in anorexia, weight loss, diarrhea, colic, and death. Cyathostome ova are easily detected in feces, but ova may not be present during larval cyathostomiasis. Increased concentrations of beta-globulins, hypoalbuminemia, anemia, and leukocytosis occur inconsistently. Two major problems in the treatment of cyathostome infections are anthelmintic resistance and the insusceptibility of encysted larvae to recommended dosages of most anthelmintics. The major goal of cyathostome control is prevention of environmental contamination with nematode ova. Host resistance appears to protect against cyathostome disease rather than cyathostome infection, and one manifestation of this resistance appears to be prolongation of the prepatent period.

Animals↗

Observations on the population dynamics of five cyathostome nematode species of horses in northern USA.

Monthly variations in the magnitude of adult and larval cyathostome burdens were observed in 55 horses necropsied over a 15-month period in the northern USA. Peak numbers of adult cyathostomes occurred in late winter (March) and late summer (September). Larval cyathostomes demonstrated peak numbers from February to April and again in October, beginning one month earlier than the spring adult peak and one month after the autumn adult peak, respectively. The reproductive status of individual female Cyathostomum catinatum, Cyath coronatum, Cylicocyclus nassatus, Cylicostephanus goldi and Cylicostephanus longibursatus was classified as immature, gravid or spent. Seasonal changes in these classifications were monitored as a marker for the age structure of these populations. Each reproductive category of female small strongyle was dominant during only one period per year and these periods were similarly distributed for all five species examined. Immature cyathostomes were most common from late winter to spring (March to May); gravid worms were predominant beginning in spring (April/May) and continuing into autumn (October to December). Spent females prevailed from autumn through winter (October to March/April).

Animals↗