Studies of respiratory disease in random-source laboratory dogs: viral infections in unconditioned dogs.

A prospective study was conducted to identify the viruses causing respiratory diseases in unconditioned, random-source dogs. During the quarantine period, respiratory disease occurred in 86 of 167 (52%) dogs, and 34 (21%) died. Most affected dogs had a distemper-like illness which required extensive and prolonged care. Histopathologic studies confirmed the diagnosis of canine distemper in 10 of 12 (83%) fatal infections examined. Sixty-seven of 91 (74%) dogs which arrived without canine distemper antibody became ill, and 30 (32%) died. In contrast, only 16 of 67 (24%) dogs with canine distemper antibody had respiratory disease, and only 3 (4%) died. Parainfluenza SV5 and canine adenovirus--type II were recovered from 27 of 54 and 22 of 54 sick dogs, respectively. Canine herpesviruses, canine coronaviruses, and canine parvoviruses were less frequently isolated. Increased antibody titers to SV5 were found consistently, and rises in titer to the other viruses were demonstrated. Many of the sick dogs were infected with two or more viruses. Although several viral agents were detected during these epizootics, prevention of canine distemper appeared to be the key to controlling severe, prolonged, and often fatal respiratory disease.     

Prevailing hyperglycemia is critical in the regulation of glucose metabolism during exercise in poorly controlled alloxan-diabetic dogs.

The separate impacts of the chronic diabetic state and the prevailing hyperglycemia on plasma substrates and hormones, in vivo glucose turnover, and ex vivo skeletal muscle (SkM) during exercise were examined in the same six dogs before alloxan-induced diabetes (prealloxan) and after 4-5 wk of poorly controlled hyperglycemic diabetes (HGD) in the absence and presence of approximately 300-min phlorizin-induced (glycosuria mediated) normoglycemia (NGD). For each treatment state, the approximately 15-h-fasted dog underwent a primed continuous 150-min infusion of [3-(3)H]glucose, followed by a 30-min treadmill exercise test (approximately 65% maximal oxygen capacity), with SkM biopsies taken from the thigh (vastus lateralis) before and after exercise. In the HGD and NGD states, preexercise hepatic glucose production rose by 130 and 160%, and the metabolic clearance rate of glucose (MCRg) fell by 70 and 37%, respectively, compared with the corresponding prealloxan state, but the rates of glucose uptake into peripheral tissues (Rd(tissue)) and total glycolysis (GF) were unchanged, despite an increased availability of plasma free fatty acid in the NGD state. Exercise-induced increments in hepatic glucose production, Rd(tissue), and plasma-derived GF were severely blunted by approximately 30-50% in the NGD state, but increments in MCRg remained markedly reduced by approximately 70-75% in both diabetic states. SkM intracellular glucose concentrations were significantly elevated only in the HGD state. Although Rd(tissue) during exercise in the diabetic states correlated positively with preexercise plasma glucose and insulin and GF and negatively with preexercise plasma free fatty acid, stepwise regression analysis revealed that an individual's preexercise glucose and GF accounted for 88% of Rd(tissue) during exercise. In conclusion, the prevailing hyperglycemia in poorly controlled diabetes is critical in maintaining a sufficient supply of plasma glucose for SkM glucose uptake during exercise. During phlorizin-induced NGD, increments in both Rd(tissue) and GF are impaired due to a diminished fuel supply from plasma glucose and a sustained reduction in increments of MCRg.     

Effects of parentage on competitive ability and vulnerability to predation in Hyla chrysoscelis tadpoles

Four sibships of Hyla chrysoscelis larvae were used to examine the effects of parentage on mass at day 23 of growth and on vulnerability to predation. The H. chrysoscelis larvae were raised alone, in competition with Rana clamitans larvae, and in competition with siblings. Vulnerability to predation by adult Notophthalmus viridescens dorsalis was evaluated for Hyla that had been raised in competition with siblings. Sibships differed in body mass and vulnerability to predation. Competition with Rana or with siblings resulted in a major reduction in body mass. There were no interactions between the effects of parentage and level of competition on body mass. Vulnerability to predation by newts appeared to be determined partially by body mass and partially by parental influences on factors other than body mass. If the differences observed between factors determining body mass and vulnerability to predation reflect negative genetic correlations among these determinants, tradeoffs between selection for increased competitive ability and reduced vulnerability to predators may partially account for the existence of genetic variation for growth rate in larval Hyla.     

Relationship of the Frequency of Isolation of Salmonellae to Their Resistance to Drying and Freezing

The resistance of different Salmonella serotypes to drying and freezing has been shown to be related to their incidence in salmonellosis.     

On the origins of esterases

Comparisons among the primary sequences of five cloned eukaryotic esterases reveal two distinct lineages, neither bearing any significant overall sequence similarity to the functionally related serine protease multigene family. We have not eliminated the possibility that the esterases may have residual conformational similarities to the serine proteases. However, our profile analysis and analyses of the predicted conformations of the esterases reveal little similarity to the serine proteases. Four of the esterase proteins share 27%-53% overall sequence similarity and evidence of a catalytic mechanism involving the same Arg- Asp-Ser or His-Asp-Ser charge relay. We propose that these four esterases, three of them cholinesterases, form part of a multigene family essentially separate from the serine proteases.      

Effects of emerging infectious diseases on host population genetics: a review

Emerging infectious diseases threaten the survival of many species and populations by causing large declines and altering life history traits and population demographics. Therefore, it is imperative to understand how diseases impact wildlife populations so that effective management strategies can be planned. Many studies have focused on understanding the ecology of host/pathogen interactions, but it is equally important to understand the effects on host population genetic structure. In this review, we examined the literature on how infectious diseases influence host population genetic makeup, with a particular focus on whether or not they alter gene flow patterns, reduce genetic variability, and drive selection. Although the results were mixed, there was evidence for all of these outcomes. Diseases often fragmented populations into small, genetically distinct units with limited gene flow among them. In some cases, these isolated populations showed the genetic hallmarks of bottlenecks and inbreeding, but in other populations, there was sufficient gene flow or enough survivors to prevent genetic drift and inbreeding. Direct evidence of diseases acting as selective pressures in wild populations is somewhat limited, but there are several clear examples of it occurring. Also, several studies found that gene flow can impact the evolution of small populations either beneficially, by providing them with variation, or detrimentally, by swamping them with alleles that are not locally adaptive. Thus, differences in gene flow levels may explain why some species adapt while others do not. There are also intermediate cases, whereby some species may adapt to disease, but not at a rate that is meaningful for conservation purposes.     

Using training to moderate chimpanzee aggression during feeding

The effects of human and nonhuman primate interactions on the well-being of captive nonhuman primates have been studied less rigorously than other forms of environmental improvement. Human intervention might be used to moderate severe aggression of socially housed animals at feeding times, one of the most common behavioral management problems. In this study, positive reinforcement training techniques were applied to reduce a dominant male chimpanzee's aggression and chasing during meals. Verbal commands and food reinforcers were used to train him to sit and remain seated while other group members received and ate their share of produce. Observational data were collected recording all instances of agonism in the group during periods when meals were fed and during times when no meals were offered, both before and after the training was accomplished. Multivariate analysis of variance for repeated measures results indicated that the training program successfully reduced the group's incidence of displaying, submission, and aggression during feeding periods. This effect was specific to the times meals were fed; there was no generalized reduction in the group's agonism after the training. This study exemplifies the use of positive reinforcement techniques to modify chimpanzee social dynamics during a problematic situation and of observational data to evaluate quantitatively the behavioral effects of the training. Training can be employed to help solve behavioral management problems among socially housed animals, and it can help improve the psychological well-being of captive chimpanzees. © 1994 Wiley-Liss, Inc.