The Impact of Animal Disease on Human Health and Welfare

Animal diseases are of considerable importance to human welfare both as a cause of illness in man and as a factor in reducing the food potential of the world. Perhaps the most important factor affecting the less developed areas is malnutrition and, while explosive epidemics among animals are of great importance, the most important sources of losses are the chronic, sub-acute or sub-clinical infections, especially those caused by the parasitic worms.     

Rice Pi-ta gene Confers Resistance to the Major Pathotypes of the Rice Blast Fungus in the United States

ABSTRACT The Pi-ta gene in rice prevents the infection by Magnaporthe grisea strains containing the AVR-Pita avirulence gene. The presence of Pi-ta in rice cultivars was correlated completely with resistance to two major pathotypes, IB-49 and IC-17, common in the U.S. blast pathogen population. The inheritance of resistance to IC-17 was investigated further using a marker for the resistant Pi-ta allele in an F(2) population of 1,345 progeny from a cross of cv. Katy with experimental line RU9101001 possessing and lacking, respectively, the Pi-ta resistance gene. Resistance to IC-17 was conferred by a single dominant gene and Pi-ta was not detected in susceptible individuals. A second F(2) population of 377 individuals from a reciprocal cross between Katy and RU9101001 was used to verify the conclusion that resistance to IC-17 was conferred by a single dominant gene. In this cross, individuals resistant to IC-17 also were resistant to IB-49. The presence of Pi-ta and resistance to IB-49 also was correlated with additional crosses between 'Kaybonnet' and 'M-204', which also possess and lack Pi-ta, respectively. A pair of primers that specifically amplified a susceptible pi-ta allele was developed to verify the absence of Pi-ta. We suggest that Pi-ta is responsible for resistance to IB-49 and IC-17 and that both races contain AVR-Pita genes.     

Differential effects of the endocrine-disrupting compounds bisphenol-A and octylphenol on gonadotropin secretion, in prepubertal ewe lambs

This study examined the effects of long-term exposure to the endocrine-disrupting compounds (EDCs) Bisphenol-A (BPA) and Octylphenol (OP) on gonadotrophin secretion in pre-pubertal female sheep. Four-week-old, female lambs were randomly allocated to four groups (n=6), and twice each week treated with i.m. injections of either corn oil (vehicle controls), diethylstilbestrol (DES; 0.175mg/kg), BPA (3.5mg/kg) or OP (3.5mg/kg). After 5 weeks of treatment, animals were ovariectomized (ovx) and ovary weights recorded. Two weeks later, blood samples were collected from lambs every 15min for 6h, for LH pulse analysis. Animals were then euthanased and adrenal and kidney weight recorded. An age-related increase in tonic LH secretion was noted in Control, BPA- and OP-treated lambs, but was absent in DES-treated lambs. Following ovx, LH secretion increased in all except DES-treated lambs; FSH concentrations increased in all groups. BPA and DES significantly suppressed LH pulse frequency (C: 6.7+/-0.3pulses/6h, DES: 1.5+/-0.8pulses/6h, BPA: 2.3+/-0.8pulses/6h) and amplitude (C: 7.1+/-1.0ng/ml, DES: 1.9+/-0.6ng/ml, BPA: 1.6+/-0.4ng/ml). OP had no effect on LH secretion (Frequency: 5.8+/-0.5pulses/6h, amplitude: 8.0+/-2.0ng/ml). Ovary weight was similar among all groups. Results show that chronic in vivo exposure of prepubertal female lambs to BPA, at levels lower than those reported previously, can have significant effects on LH secretion that are comparable to those seen following exposure to the known xenoestrogen, DES. Exposure to an equal dose of the EDC OP, over the equivalent period of time was without effect on gonadotropin secretion in the prepubertal ewe lamb. These results indicate that exposure of prepubertal female lambs to the EDC BPA can induce significant effects on gonadotropin secretion, the potential long-term effects of exposure and the effects of these changes on reproductive performance and efficacy, therefore, merit further study.     

In vitro effects and in vivo efficacy of a novel cyclooxygenase-2 inhibitor in dogs with experimentally induced synovitis

OBJECTIVE: To determine cyclooxygenase-2 (COX-2) selectivity, pharmacokinetic properties, and in vivo efficacy of ML-1,785,713 in dogs. ANIMALS: 21 healthy male and female mixed-breed dogs and 24 healthy male Beagles. PROCEDURE: Selectivity of ML-1,785,713 for inhibiting COX-2 was determined by comparing the potency for inhibiting cyclooxygenase-1 (COX-1) with that of COX-2 in canine blood. Pharmacokinetic properties were determined after i.v. (2 mg/kg) and oral (8 mg/kg) administration in female mixed-breed dogs. In vivo efficacy was evaluated in male mixed-breed dogs with urate crystal-induced synovitis. Prophylactic efficacy was evaluated by administering ML-1,785,713 two hours before induction of synovitis whereas therapeutic efficacy was determined by administering ML-1,785,713 one hour after induction of synovitis. RESULTS: Blood concentrations that resulted in 50% inhibition of COX-1 and COX-2 activity in vitro were 119.1 microM and 0.31 microM, respectively, and selectivity ratio for inhibiting COX-2 relative to COX-1 was 384. ML-1,785,713 had high oral bioavailability (101%), low systemic clearance (77 mL/min/kg), and an elimination half-life of 5.9 hours. ML-1,785,713 was efficacious when administered prophylactically and therapeutically to dogs with urate crystal-induced synovitis. CONCLUSIONS AND CLINICAL RELEVANCE: ML-1,785,713 is a novel, potent COX-2 inhibitor that is the most selective COX-2 inhibitor described for use in dogs to date. ML-1,785,713 has oral bioavailability and low systemic clearance that is comparable to other non-steroidal anti-inflammatory drugs. It is effective after prophylactic and therapeutic administration in attenuating lameness in dogs with urate crystal-induced synovitis. Drugs that specifically inhibit COX-2 and not COX-1 at therapeutic doses may have an improved tolerability profile, compared with nonselective non-steroidal anti-inflammatory drugs.     

Evaluation of an outbreak of West Nile virus infection in horses: 569 cases (2002)

OBJECTIVE: To characterize an outbreak of West Nile virus (WNV) infection in horses in North Dakota in 2002, evaluate vaccine effectiveness, and determine horse characteristics and clinical signs associated with infection. DESIGN: Retrospective study. ANIMALS: 569 horses. PROCEDURE: Data were obtained from veterinary laboratory records, and a questionnaire was mailed to veterinarians of affected horses. RESULTS: Affected horses were defined as horses with typical clinical signs and seroconversion or positive results of virus isolation; affected horses were detected in 52 of the 53 counties and concentrated in the eastern and northeastern regions of the state. Among affected horses, 27% (n = 152) were vaccinated against WNV, 54% (309) were not, and 19% (108) had unknown vaccination status; 61 % (345) recovered, 22% (126) died, and 17% (98) had unknown outcome. The odds of death among nonvaccinated horses were 3 and 16 times the odds among horses that received only 1 or 2 doses of vaccine and horses that were vaccinated according to manufacturer's recommendations, respectively. Horses with recumbency, caudal paresis, and age > 5 years had higher odds of death, whereas horses with incoordination had lower odds of death, compared with affected horses without these characteristics. CONCLUSIONS AND CLINICAL RELEVANCE: Vaccination appears to have beneficial effects regarding infection and death caused by WNV.     

Drilling to gabbro in intact ocean crust

Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D.     

Color stability, reducing activity, and cytochrome c oxidase activity of five bovine muscles

The objective was to characterize the beef psoas major (PM), longissimus lumborum (LL), superficial semimembranosus (SSM), deep semimembranosus (DSM), and semitendinosus (ST) muscles for differences in instrumental and visual color, metmyoglobin-reducing activity (MRA), total reducing activity (TRA), and cytochrome c oxidase activity. The LL and ST had the most color stability and MRA (p < 0.05), the DSM and PM had the least (p < 0.05), and values for the SSM were intermediate. Visual color (r = -0.66) and a and chroma (r = 0.68) were more correlated with MRA than with TRA (r < 0.14 for all measures). This research supports previous reports that color stability among muscles is variable and that MRA is more useful than TRA for explaining the role of reducing activity in muscle-color stability.