A new anthelmintic assay using rats infected with Trichostrongylus colubriformis.     

K A Gration  B F Bishop  M R Martin-Short  A Herbert 《Veterinary parasitology》1992,42(3-4):273-279

A new anthelmintic assay is described which uses immunosuppressed (60 ppm hydrocortisone acetate in diet) rats infected with the nematode Trichostrongylus colubriformis. Immunosuppressed rats were infected with 1500 T. colubriformis larvae, treated either orally or subcutaneously on Day 14 post-infection and necropsied 4 days after treatment. The worm counts in immunosuppressed control animals averaged 775 worms per rat. A range of benzimidazoles, levamisole hydrochloride, morantel tartrate, 22,23-dihydroavermectin B1a and alpha-milbemycin have been evaluated in the assay. The ED95 values obtained indicate that rats infected with T. colubriformis provide a highly predictive model for assaying the activity of experimental drugs in vivo prior to studies in ruminants.  相似文献   

Effect of host resistance on the feeding and reproductive performance of Haemaphysalis punctata and Ixodes ricinus ticks     

A J Alani  I V Herbert 《Research in veterinary science》1987,42(2):238-243

A study was made to assess the influence of host response on Haemaphysalis punctata and Ixodes ricinus biology by comparing the effects of feeding ticks on previously uninfested hosts with those fed on previously sensitised hosts. Adult H punctata were fed on sheep; larvae and nymphs of H punctata and I ricinus were fed on rabbits. The engorgement weights of all instars studied that fed on sensitised hosts fell very gradually with successive infestations. These weight reductions were greater at high than at low levels of infestation. In previously sensitised hosts, the engorgement period of all instars was prolonged: the percentage of instars which completed engorgement and engorgement weights were reduced. The host's clinical and immune response markedly affected the fecundity of adult female ticks and the viability and hatchability of the laid eggs. Eighty per cent of female H punctata successfully laid eggs following the first infestation and the hatchability of eggs was 85 per cent. The numbers successfully laying eggs decreased to 60 per cent during the fifth and sixth infestations and was less than 20 per cent following the seventh infestation; the hatchability decreased similarly. There was no marked effect on the development of immature instars when fed on sensitised rabbits.  相似文献   

Feline miliary eczema: megestrol acetate does not suppress immune responses     

M J Browning  W J Herbert  R G White 《Research in veterinary science》1983,35(2):245-246

Megestrol acetate was found to have no influence on immunological skin and corneal reactivity nor on antibody responses in guinea pigs. Its curative effect in feline miliary eczema is probably not, therefore, the result of interference with the immune response.  相似文献   

The pathogenesis of Babesia motasi (Wales) infection in sheep     

A J Alani  I V Herbert 《Veterinary parasitology》1988,27(3-4):209-220

Studies on the pathogenesis of Babesia motasi (Wales) infection following blood transfusion of infected blood to normal or splenectomised recipients showed that the intact animal is refractory to infection but that infection in splenectomised animals caused weight loss, fever, anorexia, lassitude and a macrocytic hypochromic anaemia which coincided with the peak of parasitaemia. There was an initial leucocytosis, largely due to a neutrophilia. The prepatent period following blood transfusion was 2-3 days. Unconjugated and conjugated (direct) bilirubin levels increased from pre-infection levels to peaks of 1.43 and 0.70 mg/100 ml of blood, respectively. Serum glutamic pyruvic acid transaminases (SGPT) increased slightly but serum glutamic-oxaloacetic acid transaminases (SGOT) and blood sugar (glucose) levels did not show significant changes after infection. Total serum protein levels increased temporarily and then returned to normal. Blood urea nitrogen levels increased, with biphasic peaks (76.32 and 86.29 mg/100 ml) on Days 2 and 8 post-patency. Clinical infections even in splenectomised sheep, were mild and of short duration, although recovered sheep remained carriers.  相似文献   

A method for estimating the age of coenuri of Taenia multiceps recovered from the brains of sheep     

J M Willis  I V Herbert 《The Veterinary record》1987,121(10):216-218

The age of coenurus metacestodes from the brains of sheep has been estimated by counting the average number of scolices in each cluster on the coenurus wall and relating it to a calculated regression line derived from an examination of cysts of known age. The method has been applied to 17 natural infections and its value is discussed.  相似文献   

The immune response of pigs to infection with the stomach worm Hyostrongylus rubidus (Hassall and Stiles, 1892): I. Antibody production in response to primary infection     

H.V. Smith  I.V. Herbert 《Veterinary parasitology》1976,1(4):327-335

Pigs infected with single doses of third stage Hyostrongylus rubidus larvae showed a detectable circulating agglutinin response as early as 2 days post infection. Although titres fluctuated considerably before patency, a trend in antibody production could be detected which followed the active development and growth of larvae in the gastric mucosa. At patency, titres showed a large, rapid increase followed by an equally dramatic decrease, after which titres remained stable or increased gradually.Pigs infected with adult worms did not show a detectable agglutinin response until 7 days post infection or later. Little fluctuation in titre was observed.Response variation between different levels of infection was great as was the variation between different litters subjected to the same infection regime. No statistical difference could be found in total antibody production between pigs infected with different larval numbers at any time during the duration of the trial.  相似文献   

Diskriminanzanalytische Untersuchungen Zur Identifikation Der Auslösefaktoren Für Rutschungen In Verschiedenen Höhenstufen Der Kolumbianischen Anden     

Herbert Neuland 《CATENA》1980,7(1):205-221

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Tyrosine metabolism in Aedes aegypti: Arrest of sclerotization by MON 0585 and diflubenzuron     

Eliezar Zomer  Herbert Lipke 《Pesticide biochemistry and physiology》1981,16(1):28-37

Lipid from cuticle and viscera sequestered 35 and 40%, respectively, of the diflubenzuron taken up by larvae of Aedes aegypti. The rate of toxicant uptake was linear for the first 2 days of exposure. Following treatment of larvae with a mixture of MON 0585 and diflubenzuron, tanning agents and pigments were discharged into the rearing medium during pupation. In the course of poisoning, body fluids and cuticle accumulated soluble arylated peptides and tanning agents at the expense of the sclerotized mucoprotein complex. Changes in protein composition of the integument were indicated by decreased titers of bound phenylalanine and serine in both the immature and pupal stages, however, visual symptoms of poisoning were absent in larvae. Three amino acids linked to citric acid cycle oxidations, namely, aspartic and glutamic acids and proline, declined sharply in body fluids of poisoned animals while a conjugate resembling N-acetyldopamine-O-glucoside was retained. These biochemical lesions suggest the action of MON 0585 was due to (a) loss of benzenoid precursors of the crosslink to the rearing medium; (b) faulty active transport of tanning agents; and (c) unavailability of receptor sites for arylating groups on side chains destined for bridging.  相似文献   

Planetary science. The giant impact formation of the Moon     

Palme H 《Science (New York, N.Y.)》2004,304(5673):977-979

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The occurrence and distribution of Salmonella enteritidis and other serovars on California egg laying premises: a comparison of two sampling methods and two culturing techniques     

Kinde H  Castellan DM  Kass PH  Ardans A  Cutler G  Breitmeyer RE  Bell DD  Ernst RA  Kerr DC  Little HE  Willoughby D  Riemann HP  Snowdon JA  Kuney DR 《Avian diseases》2004,48(3):590-594

Between the summer of 1998 and the winter of 2000, Salmonella analysis was performed on 2128 single and 532 pooled manure drag swabs obtained from 133 California commercial egg laying farms. The isolation of Salmonella from all rows and from all flocks using single or pooled swabs was 80% and 92%, respectively. Hence, there was no statistical difference between single vs. pooled swabs in terms of identifying Salmonella on a row or flock basis. A total of 14 serogroups comprising 44 serotypes were isolated from 123 of 133 farms. When the top 10 serotypes were considered, there was no significant difference in the range of serotypes isolated by the two culturing methods. The overall S. enteritidis prevalence for California flocks was 10.5% (14/133). The overall row prevalence for S. enteritidis for all the farms was 1.1% (24/2128), and the overall pool prevalence was 2.4% (13/532). Sixty percent (12/20) of the S. enteritidis isolates from the positive farms were phage type 4, and 40% (8/20) represented five other phage types (1, 6B, 7, 8, and 28).  相似文献