Cryptosporidium ryanae n. sp. (Apicomplexa: Cryptosporidiidae) in cattle (Bos taurus)   总被引：1，自引：0，他引：1  

Fayer R  Santín M  Trout JM 《Veterinary parasitology》2008,156(3-4):191-198

A new species, Cryptosporidium ryanae, is described from cattle. Oocysts of C. ryanae, previously identified as the Cryptosporidium deer-like genotype and recorded as such in GenBank (AY587166, EU203216, DQ182597, AY741309, and DQ871345), are similar to those of Cryptosporidium parvum and Cryptosporidium bovis but smaller. This genotype has been reported to be prevalent in cattle worldwide. Oocysts obtained from a calf for the present study are the smallest Cryptosporidium oocysts reported in mammals, measuring 2.94-4.41micromx2.94-3.68microm (mean=3.16micromx3.73microm) with a length/width shape index of 1.18 (n=40). The pre-patent period for two Cryptosporidium-na?ve calves fed C. ryanae oocysts was 11 days and the patent period was 15-17 days. Oocysts were not infectious for BALB/c mice or lambs. Fragments of the SSU-rDNA, HSP-70, and actin genes amplified by PCR were purified and PCR products were sequenced. Multi-locus analysis of the three unlinked loci demonstrated the new species to be distinct from all other species and also demonstrated a lack of recombination, providing further evidence of species status. Based on morphological, molecular and biological data, this geographically widespread parasite found only in Bos taurus calves is recognized as a new species and is named C. ryanae.  相似文献   

Ablation of a congenital neck mass in a foal   总被引：1，自引：0，他引：1       下载免费PDF全文

Field JR  Trout D  Physick-Sheard PW 《The Canadian veterinary journal. La revue veterinaire canadienne》1990,31(9):643-644

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Prevalence of Giardia duodenalis genotypes in adult dairy cows     

Trout JM  Santín M  Fayer R 《Veterinary parasitology》2007,147(3-4):205-209

The prevalence of Giardia duodenalis genotypes was determined in adult dairy cows. Fecal specimens were collected from two farms each in Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. Specimens, cleaned of fecal debris and concentrated using CsCl density gradient centrifugation, were subjected to PCR and DNA sequence analysis. The prevalence of G. duodenalis infection, ranged from 3% to 64%, with an average prevalence of 27% (144 positive cows out of 541 examined). DNA sequence analysis of the 16S rRNA gene revealed the presence of both Assemblage A and Assemblage E, G. duodenalis. Overall, Assemblage E was present in 25% of all animals tested and Assemblage A was present in 2% of the animals. As a percentage of G. duodenalis isolates, Assemblage E represented 94% and Assemblage A represented 6%. Although, most of the cows were infected with a genotype that is not known to be infectious for humans, adult cows on five farms did harbor varying levels of zoonotic Assemblage A, G. duodenalis. Therefore, although adult cows do not appear to be a significant source of human infectious cysts in the environment, the risk from this age group should not entirely be discounted.  相似文献   

The effects of perineural and intrasynovial anaesthesia of the equine foot on subsequent magnetic resonance images     

B. Black  N. C. Cribb  S. G. Nykamp  J. J. Thomason  D. R. Trout 《Equine veterinary journal》2013,45(3):320-325

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Surgical repair of rectovaginal fistulae in mares: Twelve cases (1983-1991)          下载免费PDF全文

Desjardins MR  Trout DR  Little CB 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(4):226-231

The case records of 12 mares at the Ontario and Atlantic Veterinary Colleges were reviewed to evaluate the success rates of surgical techniques used to repair rectovaginal fistulae. A modified horizontal perineal technique was used in eight mares; it was unsuccessful in one mare, but the fistula was subsequently successfully repaired using the same technique. One rectovaginal fistula that was converted to a third-degree perineal laceration was successfully repaired on the third attempt, using the suture principles of the modified horizontal perineal technique. A modified transvaginal technique was used in three mares, in two of which it failed; their fistulae were subsequently converted to third-degree perineal lacerations and repaired using a one-stage closure. We conclude that the modified horizontal perineal technique is a one-stage procedure that is technically easy to perform, results in less tension on the suture lines, and is effective in modifying poor vulvar conformation.  相似文献   

Regression analysis of use-dilution disinfectant test data as an alternative to current registration practices     

G R Walter  J R Trout 《Journal of the Association of Official Analytical Chemists》1987,70(3):413-416

The historical application of probit analysis applied to the use-dilution disinfectant test is discussed. Attention is focused on earlier work which either deleted or incompletely applied confidence limits leading to much current controversy in disinfectant test interpretation. It is proposed that the probit analysis approach applied to disinfectants is indeed feasible and that a more complete application of confidence limits to the assay will yield more reliable data than those currently required for disinfectant product registration with the Environmental Protection Agency. A suggested modified registration protocol using probit analysis is offered as an alternative to the current registration guidelines.  相似文献   

Prevalence of Microsporidia, Cryptosporidium spp., and Giardia spp. in beavers (Castor canadensis) in Massachusetts.     

Ronald Fayer  Mónica Santín  James M Trout  Stephen DeStefano  Kiana Koenen  Taranjit Kaur 《Journal of zoo and wildlife medicine》2006,37(4):492-497

Feces from 62 beavers (Castor canadensis) in Massachusetts were examined by fluorescence microscopy (IFA) and polymerase chain reaction (PCR) for Microsporidia species, Cryptosporidium spp., and Giardia spp. between January 2002 and December 2004. PCR-positive specimens were further examined by gene sequencing. Protist parasites were detected in 6.4% of the beavers. All were subadults and kits. Microsporidia species were not detected. Giardia spp. was detected by IFA from four beavers; Cryptosporidium spp. was also detected by IFA from two of these beavers. However, gene sequence data for the ssrRNA gene from these two Cryptosporidium spp.-positive beavers were inconclusive in identifying the species. Nucleotide sequences of the TPI, ssrRNA, and beta-giardin genes for Giardia spp. (deposited in GenBank) indicated that the four beavers were excreting Giardia duodenalis Assemblage B, the zoonotic genotype representing a potential source of waterborne Giardia spp. cysts.  相似文献   

Water use of young Thompson Seedless grapevines in California     

L.?E.?WilliamsEmail author  C.?J.?Phene  D.?W.?Grimes  T.?J.?Trout 《Irrigation Science》2003,22(1):1-9

Water use of Thompson Seedless grapevines during the first 3 years of vineyard establishment was measured with a large weighing lysimeter near Fresno, California. Two grapevines were planted in a 2ǸǶ m deep lysimeter in 1987. The row and vine spacings in the 1.4-ha vineyard surrounding the lysimeter were approximately 3.51 and 2.15 m, respectively. Vines in the lysimeter were furrow-irrigated from planting until the first week of September in 1987. They were subsequently irrigated with subsurface drip-irrigation whenever they had used 2 mm of water, based upon the area of the lysimeter (equivalent to 8 liters per vine). The trellis system, installed the second year, consisted of a 2.13 m long stake, driven 0.45 m into the soil with a 0.6 m cross-arm placed at the top of the stake. Crop coefficients (K_c) were calculated using measured water losses from the lysimeter (ET_c) and reference crop evapotranspiration (ET_o) obtained from a CIMIS weather station located 2 km from the vineyard. Water use of the vines in 1987 from planting until September was approximately 300 mm, based on the area allotted per vine in the vineyard surrounding the lysimeter. Daily water use just subsequent to a furrow-irrigation event exceeded ET_o (>6.8 mm day^у). Water use from budbreak until the end of October in 1988 and 1989 was 406 and 584 mm, respectively. The initiation of subsurface drip-irrigation on 23 May 1988 and 29 April 1989 doubled ET_c measured prior to those dates. Estimates of a 'basal' K_c increased from 0.1 to 0.4 in 1987. The seasonal K_c in 1988 increased throughout the season and reached its peak (0.73) in October. The highest K_c value in 1989 occurred in July. It is suggested that the seasonal and year-to-year variation in the K_c was a result of the growth habit of the vines due to training during vineyard establishment. The results provide estimates of ET_c and K_c for use in scheduling irrigations during vineyard establishment in the San Joaquin Valley of California and elsewhere with similar environmental conditions.  相似文献   

Sediment,erosion and water intake in furrows     

M. J. Brown  W. D. Kemper  T. J. Trout  A. S. Humpherys 《Irrigation Science》1988,9(1):45-55

Summary Observations and studies were conducted on the origin and destination of sediment in irrigation water, and the effects of sediment adsorbed on the wetted perimeter of furrows on water intake and erosion. Fine sediment adsorbed on the perimeter reduced intake and increased soil water tension which was the primary mechanism holding the sediment on the perimeter. This self enhancing effect causes this thin seal to decrease erosion and intake rates. In contrast, removal of a few square centimeters of this seal by chance events after water velocities and shear forces have increased often causes reduced tensions, exfoliation of the surface seal and erosion pits which develop into head cuts.  相似文献   

Consumptive water use and crop coefficients of irrigated sunflower   总被引：2，自引：1，他引：1  

R. López-Urrea  A. Montoro  T. J. Trout 《Irrigation Science》2014,32(2):99-109

In semi-arid environments, the use of irrigation is necessary for sunflower production to reach its maximum potential. The aim of this study was to quantify the consumptive water use and crop coefficients of irrigated sunflower (Helianthus annuus L.) without soil water limitations during two growing seasons. The experimental work was conducted in the lysimeter facilities located in Albacete (Central Spain). A weighing lysimeter with an overall resolution of 250 g was used to measure the daily sunflower evapotranspiration throughout the growing season under sprinkler irrigation. The lysimeter container was 2.3 m × 2.7 m × 1.7 m deep, with an approximate total weight of 14.5 Mg. Daily ET _c values were calculated as the difference between lysimeter mass losses and lysimeter mass gains divided by the lysimeter area. In the lysimeter, sprinkler irrigation was applied to replace cumulative ET _c, thus maintaining non-limiting soil water conditions. Seasonal lysimeter ET _c was 619 mm in 2009 and 576 mm in 2011. The higher ET _c value in 2009 was due to earlier planting and a longer growing season with the maximum cover coinciding with the maximum ET _o period. For the two study years, maximum average K _c values reached values of approximately 1.10 and 1.20, respectively, during mid-season stage and coincided with maximum ground cover values of 75 and 88 %, respectively. The dual crop coefficient approach was used to separate crop transpiration (K _cb) from soil evaporation (K _e). As the crop canopy expanded, K _cb values increased while the K _e values decreased. The seasonal evaporation component was estimated to be about 25 % of ET _c. Linear relationships were found between the lysimeter K _cb and the canopy ground cover (f _c) for the each season, and a single relationship that related K _cb to growing degree-days was established allowing extrapolation of our results to other environments.  相似文献