Strongyle infections in ponies. I. Response to intermittent thiabendazole treatments.
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A group of seven ponies naturally infected with large numbers of small strongyles and raised under conditions to minimize reinfection were treated periodically over a three year span with thiabendazole at the rate of 44 mg/kg body weight. Based on the absence of worm eggs in the feces following each treatment, thiabendazole removed the adult strongyles present with a new population subsequently developing by maturation of inhibited larvae. It took as many as four or five treatments to eliminate or reduce significantly the worm burdens present in the ponies under the conditions of this study. Strongyle eggs started to reappear in the feces about six weeks after treatment and following the first treatment the mean egg counts rose to the pretreatment level. On successive treatments the interval for worm eggs to appear in the feces lengthened and mean egg counts never rose quite as high as immediate pretreatment levels. Hematological changes were not marked, although a small steady increase in the mean hemoglobin values and an equivalent small decrease in the mean eosinophil counts occurred in all ponies following each successive treatment. The study supports the rationale of regular anthelmintic treatment of horses in that even in the absence of reinfection, new burdens of adult worms develop following treatment. (+info)
Strongyle infections in ponies. II. Reinfection of treated animals.
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Five of seven ponies whose strongyle worm burdens had previously been removed or markedly reduced by repeated thiabendazole treatments were reinfected with doses ranging from 100,000 to 500,000 small strongyle infective larvae. Reinfection of ponies resulted in the development of clinical signs characterized by abnormal feces, marked loss of weight and delayed shedding of winter hair coats. An abrupt increase in circulating eosinophils occurred during the first three weeks following reinfection. Patent infections developed in all ponies with worm eggs appearing in the feces from 12 to 15 weeks after receiving infective larvae. Worm egg outputs followed a cyclic pattern with approximately four to five peaks in egg output per year. There was an abrupt drop in the high worm egg counts in two untreated ponies approximately two and a half years after reinfection. No worms were recovered in the feces of these animals when they were subsequently treated, suggesting that a depletion in the number of inhibited larvae present in these ponies might have occurred. (+info)
Congenital transmission of Schistosoma japonicum in pigs.
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Congenital transmission of Schistosoma japonicum in pigs was investigated by experimentally infecting sows at four weeks gestation (n = 3), 10 weeks gestation (n = 3), or a few weeks prior to insemination (n = 2). None of the piglets born to sows infected prior to insemination or in early pregnancy were found to be infected. However, all of the piglets (n = 26) born to sows infected at 10 weeks gestation were found to harbor schistosomes with S. japonicum eggs recovered from both their feces and livers. The findings show that congenital S. japonicum infection of pigs can occur if sows are infected during mid-to-late pregnancy and may have important implications not only for pigs but also for other mammalian hosts of schistosomes, including humans. (+info)
Enterotoxin-producing bacteria and parasites in stools of Ethiopian children with diarrhoeal disease.
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Enterotoxinogenic bacteria were isolated from 131 (37%) of 354 Ethiopian infants and children with acute gastrointestinal symptoms. Only one of these isolates belonged to the classical enteropathogenic serotypes of Esch. coli. Two colonies from each patient were isolated and tested for production of enterotoxin by the rabbit ileal loop test, the rabbit skin test, and an adrenal cell assay. However, only 38% of the isolated enterotoxinogenic strains were Esch. coli; the others belonged to Klebsiella, Enterobacter, Proteus, Citrobacter, Serratia, and Aeromonas. In 18 patients both isolates were toxinogenic and belonged to different species. The incidence of intestinal parasites was 35% with no apparent correlation to the occurrence of toxinogenic bacteria in the stools. (+info)
Effects of in vitro culture methods on morphological development and infectivity of Strongyloides venezuelensis filariform larvae.
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The effects of in vitro culture methods on morphological development and infectivity of Strongyloides venezuelensis filariform larvae (L3) to rats were investigated. A significantly higher body length was observed in L3 from filter paper culture (597.3 +/- 32.2 microns) than those in fecal (509.9 +/- 35.0 microns) and nutrient broth culture (503.3 +/- 31.0 microns) (P < 0.05). Larval infectivity was assessed by exposing rats to 1,000 L3 from each culture and worms were recovered from the lungs and small intestines. Recovery rate of these worms did not show any significant difference. A significantly greater body length of adults was recorded in those corresponding to the L3 harvested from filter paper (2,777.5 +/- 204.4 microns) and nutrient broth culture (2,732.5 +/- 169.8 microns) than those corresponding to the L3 obtained from fecal culture (2,600.5 +/- 172.4 microns) (P < 0.05). Although worm fecundity and EPG counts differed among culture methods but worm burdens and course of infection did not. These findings suggest that the methods of cultures have a significant effect on the morphological development of the larvae to the L3 stage, but do not influence the infectivity to rats. (+info)
Survey of Fascioloides magna in farmed wapiti in Alberta.
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The formalin-ethyl acetate sedimentation procedure was used to detect ova of the giant liver fluke, Fascioloides magna, in feces of farmed wapiti in Alberta. Twenty (3.2%) of the 629 fecal samples examined contained ova of F. magna. Thirteen (33.3%) of the 39 farms surveyed had wapiti positive for F. magna. The presence of F. magna in farmed wapiti north of the North Saskatchewan River is confirmed, and 3 areas where the infection has become endemic are identified. (+info)
Independent evaluation of the Nigrosin-Eosin modification of the Kato-Katz technique.
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A new modified quantitative Kato-Katz thick-smear technique for the detection of helminth eggs in faeces preserves hookworm eggs unaltered for a long time, while with the classic Kato-Katz technique, they disappear after approximately 2 h in tropical climates and thus slides must be read within hours after sample collection. For an independent comparison of these two laboratory techniques, faecal smears from 263 school children were examined in two surveys and prevalence, intensity of infection and costs of surveys calculated. There was no statistical difference between the methods in detecting prevalence and stratification of the sample in different classes of intensity. While there was no statistical difference for the arithmetic mean of the epg for T. trichiura and only a small difference for A. lumbricoides (P=0.04), we observed a highly significant difference for hookworm mean intensities of infections (P<0.001). From the public health viewpoint both methods provided similar results, but due to its simplicity and widespread use the classical Kato-Katz technique remains first choice for community investigation of soil-transmitted nematodes. However, the Nigrosin-Eosin approach has several advantages and can be a valuable alternative in certain circumstances. (+info)
Effect of anthelmintic treatment on sexual maturation in prepubertal beef heifers.
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Heifers treated with ivermectin at weaning have been reported to reach puberty at a younger age and lighter weight than untreated heifers. We tested the hypothesis that heifers administered ivermectin would respond with earlier follicular development and a greater LH response to a 1-mg estradiol-17beta challenge (E2C) than untreated heifers. Fall-born Angus heifers (n = 32) were randomly assigned on 284 +/- 9 d of age (215.5 +/- 20.8 kg) to receive ivermectin (IVR) or albendazole (ALB), IVR + ALB, or to remain as untreated controls (CONT). Each group (n = 8) was housed separately in adjacent pens throughout the trial and managed to gain .8 kg/heifer on a ration containing 13.2% CP, 58.8% TDN, and 49.9% DM. The CONT heifers received an additional 2.27 kg/heifer of corn silage and 1.59 kg/heifer of corn daily to maintain ADG at comparable levels. Individual body weight was recorded weekly, and nematode eggs per gram (EPG) of feces were measured every 21 d. Ultrasonography was performed on alternate days starting 2 wk prior to E2C to characterize follicular wave patterns. Follicles were separated into classes (C1 [3 to 5 mm], C2 [6 to 9 mm], and C3 [10 mm]) and sizes (largest [LF], second [SLF], third [TLF], and fourth largest follicles [FLF]). The sizes of the regressing dominant follicle 1 (DF1) and the progressing dominant follicle 2 (DF2) were also determined. Serum concentrations of LH were determined from hourly jugular blood samples collected 8 to 24 h after injection of E2C. The IVR + ALB treatment group had more C3 follicles than ALB and CONT (P < .07). The IVR-treated heifers had larger TLF than ALB and CONT (P < .04). The IVR- and IVR + ALB-treated heifers had larger FLF and DF2 than ALB and CONT (P < .1). Least squares means for DF2 were 9.5 +/- .5, 8.0 +/- .4, 9.5 +/- .3 and 8.3 +/- .3 mm, for IVR, ALB, IVR + ALB and CONT, respectively (P = .02 for treatment effect). The E2C-induced serum LH concentration did not differ with respect to treatment. We conclude that heifers administered IVR display increased follicular development, supporting our earlier investigations regarding reduced age at puberty in heifers treated with IVR near weaning. (+info)