Inducible nitric oxide synthase and nitrotyrosine in listeric encephalitis: a cross-species study in ruminants.
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Listeria monocytogenes (LM) is a Gram-positive facultative intracellular bacterium that causes fatal meningoencephalitis in humans and ruminants. A current paradigm predicts that intracellular bacteria are controlled by nitric oxide (NO) whose synthesis is catalyzed by inducible nitric oxide synthase (iNOS). The ability of macrophages (Mphi) to express iNOS shows extreme interspecies variability. Here the expression of iNOS and synthesis of NO was studied in listeric encephalitis of cattle, sheep, and goats. iNOS was expressed by a subset of Mphi in cerebral microabscesses in all three species. The level of iNOS expression and the density of cells per lesion expressing iNOS was highest in cattle, intermediate in sheep, and lowest in goats. The accumulation of nitrotyrosine (NT), an indicator of local NO synthesis, was observed in lesions of cattle but not in those of small ruminants. The density of iNOS-expressing cells in lesions was inversely correlated with the number of bacteria. No species differences were observed in regard to reactive oxygen intermediate (ROI) production by stimulated granulocytes, using the flow cytometric dihydrorhodamine-123 (DHR) method indicating ROI generation. Thus, the marked species differences in iNOS expression, NT accumulation, and LM content in lesions of ruminants with listeric encephalitis are explained by different amounts of ROI produced. It suggests that variations in the ability of Mphi to synthesize NO are of pathophysiological significance in listeriosis. (+info)
Cutaneous vasoproliferative lesions in goats.
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Abstract. In a retrospective survey of caprine neoplastic disease, eight masses were diagnosed as cutaneous vascular tumors. The typical clinical presentation was a solitary raised, bleeding mass. No predilection with regard to age, breed, sex, or anatomic location was found. Reevaluation of the microscopic features of the masses resulted in diagnoses of hamartoma (2), hemangioma (4), and hemangiosarcoma (2). An endothelial cell origin was confirmed in all seven tumors tested immunohistochemically for factor VIII-related antigen. Although rarely reported, goats display a range of cutaneous vascular growth abnormalities similar to those observed in other domestic animals. (+info)
The genomes of sheeppox and goatpox viruses.
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Sheeppox virus (SPPV) and goatpox virus (GTPV), members of the Capripoxvirus genus of the Poxviridae, are etiologic agents of important diseases of sheep and goats in northern and central Africa, southwest and central Asia, and the Indian subcontinent. Here we report the genomic sequence and comparative analysis of five SPPV and GTPV isolates, including three pathogenic field isolates and two attenuated vaccine viruses. SPPV and GTPV genomes are approximately 150 kbp and are strikingly similar to each other, exhibiting 96% nucleotide identity over their entire length. Wild-type genomes share at least 147 putative genes, including conserved poxvirus replicative and structural genes and genes likely involved in virulence and host range. SPPV and GTPV genomes are very similar to that of lumpy skin disease virus (LSDV), sharing 97% nucleotide identity. All SPPV and GTPV genes are present in LSDV. Notably in both SPPV and GTPV genomes, nine LSDV genes with likely virulence and host range functions are disrupted, including a gene unique to LSDV (LSDV132) and genes similar to those coding for interleukin-1 receptor, myxoma virus M003.2 and M004.1 genes (two copies each), and vaccinia virus F11L, N2L, and K7L genes. The absence of these genes in SPPV and GTPV suggests a significant role for them in the bovine host range. SPPV and GTPV genomes contain specific nucleotide differences, suggesting they are phylogenetically distinct. Relatively few genomic changes in SPPV and GTPV vaccine viruses account for viral attenuation, because they contain 71 and 7 genomic changes compared to their respective field strains. Notable genetic changes include mutation or disruption of genes with predicted functions involving virulence and host range, including two ankyrin repeat proteins in SPPV and three kelch-like proteins in GTPV. These comparative genomic data indicate the close genetic relationship among capripoxviruses, and they suggest that SPPV and GTPV are distinct and likely derived from an LSDV-like ancestor. (+info)
Prevalence, distribution, and host range of Peste des petits ruminants virus, Turkey.
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Peste des petits ruminants virus (PPRV, genus Morbillivirus), which causes a severe disease in sheep and goats, has only recently been officially declared to be present in Turkey. We carried out a study to determine the prevalence, distribution, and host range of PPRV in Turkey. A total of 1,607 animals, reared in 18 different locations, were monitored for the presence of antibodies to PPRV and the related virus of large ruminants, Rinderpest virus (RPV). Only two farms had animals that were free of antibody responses to either disease. Prevalence for PPRV infection varied (range 0.87%-82.6%) and was higher in sheep (29.2%) than in goats (20%). The overall antibody responses to PPRV and RPV were 22.4% and 6.28%, respectively. Two PPRVs of lineage 4, which comprises many other PPRVs whose origins are in the Middle East, the Arabian Peninsula, and southern Asia, were isolated from Turkish sheep. (+info)
Simulated preslaughter holding and isolation effects on stress responses and live weight shrinkage in meat goats.
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The objective of this experiment was to determine the effects of preslaughter isolation and feed withdrawal duration on physiological responses and shrinkage in goats. A total of 84 Spanish does (36 mo of age, average weight 35 kg) were individually weighed and scored for excitability before two replicate (day) trials. The does were feed-deprived (FD) or fed (F) in holding pens (treatment, TRT) for either 0, 7, 14, or 21 h (TIME). At the end of the holding periods, FD and F does were blood-sampled (n = 6 does/treatment/time/replicate) and weighed again to assess physiological responses and shrinkage, respectively. Individual does from each pen were blood-sampled again after imposing one of three handling post-treatments: a 15-min isolation with no visual contact with other does (I); a 15-min isolation with visual contact (IV); or no isolation (C, control). Plasma cortisol concentrations were higher at 0 h than at other holding time periods (P < 0.01). Plasma triiodothyronine, thyroxine, and leptin concentrations, and differential leukocyte counts were not influenced by any of the factors. The rate of decline in glucose concentrations over TIME was greater in FD than in F group (TRT x TIME, P < 0.05). The overall plasma creatine kinase activity peaked at 7 h before reaching a lower level at 14- and 21-h holding (P < 0.05). Plasma urea nitrogen concentrations were higher at 0- and 21-h than at 7- and 14-h holding (P < 0.01). Plasma nonesterified FA concentrations in the FD group remained at an elevated level during holding, but in the F group the levels decreased at 7 h and remained at that level (TRT x TIME, P < 0.01). Excitability scores did not have any effect on the variables measured. Shrinkage increased with longer holding time, but more prominently in the FD group (TRT x TIME, P < 0.01). Plasma cortisol concentrations were greater in I and IV groups than in the C group (P < 0.01). The novelty of environment during preslaughter holding, and social isolation may be more potent stressors than feed deprivation in goats, although shrinkage may increase with increasing feed-withdrawal times. (+info)
Towards a lower prevalence of Oestrus ovis infections in sheep in a temperate climate (south west France).
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Oestrus ovis larvae are obligatory parasites of the nasal and sinus cavities of sheep and goats. In the temperate climate of western Europe, fly attacks occur between May and October and the first stage larvae arrest their development within the host between October and February. Oestrosis clinical signs such as nasal discharge and sneezing are well known by sheep breeders in southwest France. According to veterinarian recommendations, most of them treat their animals with long lasting fasciolicides once a year at least, mainly during the fly activity period and at the beginning of the hypobiotic period (when the parasitic population is only constituted of larvae). The consequences of these therapeutic programs were analysed in a local slaughterhouse by larval counts. Both prevalence and intensities of O. ovis infections decreased between 1989-1991 (before the use of systematic treatments) and 1996-1998 (after the spread of these treatments). The use of systematic treatments during the fly activity period and the beginning of the hypobiotic period seems to be very efficient in O. ovis control and could theoretically lead to a possible 'eradication' program as with cattle hypodermosis. Nevertheless the presence of parasites in apparently healthy goats, the possibility for a fly generation to develop before the first treatment in July-August and the succession of several fly generations all around the year in southern Mediterranean and tropical countries will maintain O. ovis infections. Furthermore, there are increased concerns about drug residues on consumer health and environment and this is the basis for the prospect of alternative strategies in O. ovis control. (+info)
Sheep and goat nematode resistance to anthelmintics: pro and cons among breeding management factors.
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Although the molecular bases of resistance to anthelmintic families have been intensively studied, the contributing factors for the development of anthelmintic resistance are less well known. Clear recommendations must be given to farmers in order to delay the onset of anthelmintic resistance. Until now, the main advice has concerned the reduction of treatment frequency in order to slow down the spread of resistance. Anthelmintic resistance development depends mostly on an efficient selection pressure. This means that a high treatment frequency is neither necessary nor sufficient to select for resistance. The contribution of resistant worms, which have survived an anthelmintic treatment, to the subsequent generation is the key factor that controls resistance spread. This point is illustrated by five surveys conducted on sheep and goat farms from France and Morocco. In the 52 farms studied, less than three anthelmintic treatments were given each year. Three characteristics of breeding management can be identified in the build up of anthelmintic resistance: (1) the introduction of resistant worms through the purchase of sheep/goats or the use of common pastures, grazed by several herds/flocks, (2) under-dosing of hosts and the repeated use of one class of drugs, (3) the size of the population in refugia (infective larvae on pastures) at the time of the treatment. The role played by these breeding management factors in selecting for resistance is discussed. The most efficient way to limit the increase of anthelmintic resistance remains the reduction of the selection pressure by drugs, and optimal timing to maximise their efficacy. (+info)
The FAMACHA system for managing haemonchosis in sheep and goats by clinically identifying individual animals for treatment.
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Escalating anthelmintic resistance has made it essential to develop alternative ways of worm management for reducing selection for worm resistance, and one of the most promising approaches is to treat only those animals unable to cope with worm challenge, thus favouring unselected worms originating from untreated animals. Only clinical evaluation of anaemia (FAMACHA system) and the body condition score are regarded as being of practical value or having potential, respectively, for repeatedly examining flocks or herds and identifying individuals for treatment. Only the FAMACHA system has been tested well enough for use under practical farming conditions. However, further investigation is needed on its effect on animal production, and methods to reduce labour. Trials over several seasons showed that most sheep under severe Haemonchus contortus challenge required no, or only one treatment over a full summer season. A small minority (usually < 5%) needed more than two treatments. Most sheep could cope without regular treatment. With sufficient training, clinical evaluation of anaemia was found reliable for practical use. The overwhelming majority of trainees (some poorly literate) were able to implement the FAMACHA system successfully. The dynamics of haemonchosis in a flock can easily be monitored. Farmers, farm workers and veterinarians all rated the system very highly (> 80%) and treatment costs dropped by approximately 58%. The heritability of FAMACHA values obtained by clinical evaluation was high at 0.55 +/- 0.17% in a Merino stud with +/- 550 young rams and ewes which were the progeny of 21 sires. The FAMACHA system may not be as applicable to goats as to sheep, but further work is necessary. The main benefits of the system are the reduction in treatments, its use for discriminating between animals of varying ability to cope with infection (thus allowing genetic selection), and its lowering of selection pressure on H. contortus for anthelmintic resistance. (+info)