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Biomedical subjects

T B Stewart

Publications and source records attributed to T B Stewart.

At least 37 records · Page 2Linked to original sources
PubMed1986

Susceptibility of fourth-stage Ascaris suum larvae to fenbendazole and to host response in the pig.

Fenbendazole given at the rate of 2.5 g/kg of feed for 3 days had 100% efficacy against 4th-stage Ascaris suum larvae in 8 pigs. Eight control pigs had a total of 108 A suum. In 6 pigs infected 3 times with 3rd-stage A suum larvae and treated with fenbendazole after the larvae molted to the 4th stage, the challenge exposure-derived population was decreased by 64%. Similar sequential infections in 6 pigs similarly infected, but not treated with fenbendazole, decreased the challenge exposure-derived population by 98%; however, developing and/or adult worms from the vaccinating infections were present.

Animals↗
PubMed1986

Prevalence of toxoplasma antibodies in Southern Louisiana swine.

Sera from 1,219 pigs slaughtered in Acadian Louisiana in 1980 and 1981 were tested using the indirect hemagglutination test and microtiter system for toxoplasma antibodies and 19.2% had titers of 1:64 or higher. Pigs slaughtered in the colder months, November to March, had significantly higher seroprevalences than pigs slaughtered in the warmer months. 24.6% of 236 farm bled sows and gilts had similarly high titers.

Animals↗
PubMed1985

Micronema granuloma in the gingiva of a horse.

A well-circumscribed proliferative mass was protruding from the body of the mandible of a 4-year-old Appaloosa gelding. The mass was uniformly firm and was ulcerated on the dorsal surface. The horse was euthanatized due to extensive involvement of the jaw and difficulty in eating. Microscopically, the mass consisted of numerous discrete microgranulomas separated by bands of abundant fibrous connective tissue containing lymphocytes, plasma cells, and histiocytic macrophages. Numerous rhabditiform nematodes were in the microgranulomas as well as in the surrounding connective tissue. The nematodes were identified as Micronema species.

Animals↗
PubMed1985

Immunization of pigs against Ascaris suum by sequential experimental infections terminated with fenbendazole during larval migration.

Three experimental infections of weaning pigs with 2000 embryonated Ascaris suum eggs each, 11 days apart, followed each time by fenbendazole treatment, produced a significant host response when compared with similar infected or uninfected control pigs as assessed by response to a subsequent challenge with 100 embryonated A. suum eggs. The response elicited from pigs treated with fenbendazole on either 2, 3, and 4 days or, 6, 7, and 8 days after each experimental infection was expressed as a reduction in the number of pigs with A. suum, in the number of worms per pig, in the weight of male and female worms, and in the length of male and female worms. No differences in average daily weight gain, feed-conversion efficiency or histology of lungs and liver were noted among the 4 treatment groups.

Animals↗
PubMed1985

Experimental infections with Hyostrongylus rubidus and the effects on performance of growing pigs.

Pigs infected with Hyostrongylus rubidus at the rate of 550 larvae kg-1 body weight followed 15 days later with 220 larvae kg-1 body weight gained less weight (P less than 0.010) than uninfected control pigs. Feed efficiency (feed/gain) was 8% better (P greater than 0.10) in control than in infected pigs. Peak H. rubidus eggs per gram counts (EPG) occurred 22 days after each infection of pigs. H. rubidus EPG at necropsy were correlated with total number of adults recovered and with female/male ratio. High EPG were associated with H. rubidus populations composed of approximately equal numbers of males and females. Digestion trials consisted of pigs infected with 335 larvae kg-1 body weight compared to uninfected controls. Control pigs had higher (P less than 0.05) crude protein digestion coefficients, excreted less (P less than 0.05) N in feces and had a higher (P less than 0.05) N balance than infected pigs.

Animals↗
PubMed1985

Influence of an experimental infection of Ascaris suum on performance of pigs.

Thirty-two pigs (average 26.6 kg live weight) were individually housed and fed to study the effect of an infection of Ascaris suum (either 0, 600, 6,000 or 60,000 A. suum eggs/pig) on performance of growing-finishing pigs. Increasing the level of A. suum infection produced linear (P less than .07) and quadratic (P less than .09) effects on final weight, weight gain and average daily gain. Feed to gain ratio and number of A. suum worms recovered from the intestines of pigs at slaughter increased linearly (P less than .01) with increasing doses of A. suum eggs. Pigs receiving 60,000 A. suum eggs were 13% less (P less than .01) efficient than the noninfected controls. In each of two trials, eight crossbred barrows (15.7 kg in trial 1 and 16.1 kg body weight in trial 2) were examined for the effects of two levels of A. suum infection (0 and 20,000 eggs/pig) on digestibility coefficients for dry matter, crude protein and gross energy. The infection did not affect (P greater than .05) digestibility coefficients during the first two collection periods (d 6 through 10 and 19 through 23). However, digestion coefficients for dry matter, crude protein and gross energy obtained from the total collection period on d 33 through 37 postinfection were greater (P less than .01) for control pigs than for pigs given 20,000 A. suum eggs each. Also, N retention was greater (P less than .05) for control pigs than for infected pigs.

Animals↗
PubMed1985

Prevalence of trichinosis in southern Louisiana swine.

After an outbreak of human trichinosis in Louisiana involving 45 cases and 1 death in 1979 and 1980, a survey of pigs killed in 21 selected small slaughterhouses in southwestern Louisiana was conducted from November 1980 to September 1981. The sera from 1,225 pigs were examined for trichinella antibodies using an enzyme-linked immunosorbent assay (ELISA); 1,223 diaphragms were subjected to peptic digestion and examined for the presence of Trichinella spiralis larvae. One diaphragm (0.08%) was found to contain T spiralis (26 larvae/g of muscle) and 4 of the slaughterhouse sera were positive (0.33% seroprevalence). Pigs in 52 herds throughout the state were also tested for ELISA antibodies. The ELISA-positive pigs were not found among the 267 pigs tested from the 52 herds.

Abattoirs↗
PubMed1984

Prevalence of oocysts of Isospora suis and Eimeria spp from sows on farms with and without a history of neonatal coccidiosis.

Oocysts of Isospora suis were not found in any of 77 fecal samples from sows on farms with a history of neonatal coccidiosis. Oocysts of Isospora suis were found in 1 of 172 fecal samples from farms without a history of neonatal coccidiosis. Oocysts of Eimeria spp were found in 81.8% of the sows from farms with a history of neonatal coccidiosis and in 94.8% of the sows from farms without a history of neonatal coccidiosis. Oocysts of Isospora spp from birds were encountered as a pseudoparasite in several fecal samples.

Animals↗
PubMed1984

Performance and tissue copper concentrations of control and Ascaris suum-infected pigs fed excess dietary copper.

Ninety-eight crossbred growing-finishing swine were used in 2 experiments to investigate the interaction between naturally occurring Ascaris suum infections and excess copper ingestion. In both experiments, pigs were fed a 14% crude protein basal diet or the basal diet + 250 ppm copper. These 2 dietary groups were subsequently divided into 2 additional treatment groups (A. suum-infected or uninfected) based on worm recovery from the intestine or from fecal egg counts. Excess dietary copper improved pig performance slightly, but it dramatically increased liver, kidney and lung copper levels. The A. suum infection did not affect pig performance, but it tended (not significantly) to reduce tissue copper levels. Serum copper was not affected by dietary copper or by A. suum infection.

Animals↗
PubMed1984

Efficacy of fenbendazole against migrating Ascaris suum larvae in pigs.

Twenty-four weanling crossbred pigs were inoculated with 10,000 embryonated Ascaris suum eggs. The infection was aborted in 1 group (n = 8 pigs) with fenbendazole (3 mg/kg of body weight) given on postinfection days 2, 3, and 4 and in a 2nd group (n = 8 pigs) given fenbendazole at the same rate on postinfection days 6, 7, and 8; a 3rd group (n = 8 pigs) was not treated with fenbendazole. All pigs were necropsied at 24 days after they were inoculated. Fenbendazole was 99% effective against A suum larvae in the 2 treated groups. Early treated pigs had significantly higher daily weight gains (P less than 0.05) and were 22% more efficient in feed conversion than were nontreated pigs. Lung weights increased linearly with length of exposure to migrating A suum larvae (P less than 0.10). Liver weights were greater in treated pigs than in non-treated pigs (P less than 0.01). A negative correlation existed between number of liver lesions and liver weights of all pigs (P less than 0.05).

Animals↗
PubMed1981

Influence of an experimental infection of nodular worms (Oesophagostomum spp.) on performance of pigs.

Four trials were conducted to determine the effect of different levels of nodular worm (Oesophagostomum spp.) infection on the performance of growing-finishing swine and on digestion and absorption of nutrients by the growing pig. In each of two growing-finishing trials, 48 crossbred pigs (average body weight 26.6 kg in trial 1 and 24.4 kg in trial 2) were individually housed and given a single infection of nodular worms (0, 550, 1,100 or 1,650 infective larvae/kg body weight in trial 1 and 0, 1,500, 3,000 or 4,500 infective larvae/kg body weight in trial 2). At 21 days postinfection, pigs given either 1,100 or 1,650 nodular worm larvae/kg body weight required more feed (P less than .05) per unit gain than pigs not infected, but for the 77-day test period, as a whole, nodular worms did not significantly affect performance. in trial 2, pigs given either 3,000 or 4,500 nodular worm larvae/kg body weight were lighter (P less than .05) and gained weight slower (P less than .05) for the first 21 days postinfection than pigs not infected, while pigs given 4,500 larvae gained slower (P less than .05) than pigs on the other three treatments. During the first 21 days after infection, pigs given 4,500 larvae/kg body weight consumed less feed (P less than .05 than pigs given either 0 or 1,500 larvae. Even at the higher levels of infection, nodular worms did not significantly affect performance over the entire 77-day test period. In each of the two other trials, eight crossbred barrows (average body weight 28.8 kg in trial 1 and 28.4 kg body weight in trials 2) were examined for the effects of two levels of nodular worm infection (0 and 4,950 larvae/kg body weight) on digestion and absorption of nutrients and on N balance. Pigs experimentally infected had a lower digestion coefficient for dry matter (P less than .01), ash (P less than .05), crude fiber (P less than .01), N free extract (P less than .05) and N (P less than .05) than noninfected pigs. Pigs not infected with nodular worms had a higher (P less than .05) N balance.

Animals↗
PubMed1981

Efficacy of ivermectin against the swine kidney worm, Stephanurus dentatus.

Ivermectin in solution was given subcutaneously (in the neck) at the rate of 0.5 mg/kg of body weight to 5 sows naturally infected with kidney worm (Stephanurus dentatus). Six similar sows were used as nontreated controls. A total of 114 kidney worms were recovered from daily urine samples of 4 of the 5 treated sows (the 5th sow's samples were negative) during the first 4 days after treatment. Ten kidney worms were recovered from daily urine samples of 1 control sow on the 2nd and 3rd days of the post-treatment period. Examination of urine samples from treated sows for kidney worm eggs showed a precipitous numerical decrease. Treated animals became negative between the 5th and 12th days after treatment, and remained negative until necropsy on the 61st day. Compared with control sows, hatchability of eggs and survival of larvae from treated sows was reduced by 9% and 7%, respectively. Kidney worms were not recovered at necropsy from the treated sows, and a total of 392 kidney worms were recovered from the control sows (av 65).

Animals↗
PubMed1981

Efficacy of fenbendazole against the swine kidney worm Stephanurus dentatus.

Fenbendazole in ground feed was fed on 3 successive days at the rate of 3 mg/kg of body weight to 15 sows naturally infected with kidney worm (Stephanurus dentatus). Fifteen similar sows were used as nontreated controls. A total of 49 kidney worms were recovered from daily urine samples collected from 10 of the 15 treated sows within 5 days after the 3rd dose of treatment. One control sow passed 10 kidney worms on the 2nd and 3rd days. Urine samples from treated sows became negative for kidney worm eggs by the 5th to 12th posttreatment days, except for urine samples from 1 sow that contained a few eggs on the 12th day and another sow that contained a few eggs on the 19th and 33rd posttreatment days. Urine samples from control sows contained approximately the same number of kidney worm eggs in the posttreatment period as earlier. Compared with that in control sows, the hatchability of the parasite eggs from treated sows was greatly reduced. Kidney worms were not recovered at necropsy from the treated sows and a total of 860 kidney worms were recovered from the control sows (57 av).

Animals↗
PubMed1981

Efficacy of ivermectin against five genera of swine nematodes and the hog louse, Haematopinus suis.

Twenty pigs sequentially infected with Oesophagostomum spp, Metastrongylus spp, and Trichuris suis, and maintained on lots contaminated with Ascaris suum and Strongyloides ransomi, were assigned to 1 of 4 groups on the basis of weight, sex, and litter. Each group of pigs was given ivermectin subcutaneously at the rate of 0, 20, 100, or 500 microgram/kg of body weight. Lice on pigs were counted before treatment, on posttreatment day 1, and just before necropsy. Pigs were necropsied on posttreatment day 6 or 7, and worms were recovered and counted. Efficacies were: 0% to 100% against A suum; 66% to 100% against S ransomi; 99.4% to 99.9% against Metastrongylus spp; 0% against T suis; 3.2% to 635 against adult Oesophagostomum spp; 61.7% to 87.9% against immature Oesophagostomum spp; and 99% to 100% against Haematopinus suis.

Animals↗
PubMed1981

Efficacy of fenbendazole against five genera of swine parasites.

Thirty-three pigs were sequentially infected with Oesophagostomum spp, Metastrongylus spp, and Trichuris suis while being maintained in lots contaminated with space Ascaris suum, Strongyloides ransomi, and other parasites. Pigs were assigned to 1 of 3 groups on the basis of weight (6.8 to 25.9 kg), sex, and litter. Pigs in the 1st group were used as nontreated controls; pigs in the 2nd and 3rd groups were given fenbendazole in the feed at doses of 3 and 5 mg/kg of body weight, respectively, on 3 successive days. Pigs were necropsied either on the 4th of 5th day after completion of treatment, and worms were recovered and counted. Based on the mean numbers of worms in the control group, drug efficacies at 3 and 5 mg/kg were, respectively, 100% against A suum; 59% and 81% against S ransomi; 97% and 99.9% against Metastrongylus spp; 94% and 99.7% against T suis; and 99.9% against Oesophagostomum spp.

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