Showing papers on "Animal mortality published in 2000"

Effect of a Motorway on Mortality and Isolation of Wildlife Populations

Abstract: Although motorways could affect wildlife species, only few studies have been documented on their effects on mortality and isolation. With 2266 road-killed animals representing 97 species, the results of a study on a motorway section emphasized that traffic considerably affected vertebrate populations (14.5 animals day−1100 km−1). Road-killed animals were mainly mammals (43.2%), with predators also suffering critical impacts (21.7% vertebrates). Rare or endangered species such as the Midwife toad, the Blue throat, the little Horseshoe bat, or the European otter were among the victims. Animal mortality exponentially increased with traffic volume. Mortality reached almost 100% of migrants when no passage existed, and this barrier effect was only reduced when underground passages crossed the road restraining the mortality to 31% of migrants in Field mice and 23% in Common toads, while mortality always exceeded 74% in a road section with fauna ducts. It is reasonable to conclude that traffic severely ...

Survival motor neuron protein modulates neuron-specific apoptosis

Abstract: Spinal muscular atrophy (SMA) is attributed to mutations in the SMN1 gene, leading to loss of spinal cord motor neurons. The neurotropic Sindbis virus vector system was used to investigate a role for the survival motor neuron (SMN) protein in regulating neuronal apoptosis. Here we show that SMN protects primary neurons and differentiated neuron-like stem cells, but not cultured cell lines from virus-induced apoptotic death. SMN also protects neurons in vivo and increases survival of virus-infected mice. SMN mutants (SMNDelta7 and SMN-Y272C) found in patients with SMA not only lack antiapoptotic activity but also are potently proapoptotic, causing increased neuronal apoptosis and animal mortality. Full-length SMN is proteolytically processed in brains undergoing apoptosis or after ischemic injury. Mutation of an Asp-252 of SMN abolished cleavage of SMN and increased the antiapoptotic function of full-length SMN in neurons. Taken together, deletions or mutations of the C terminus of SMN that result from proteolysis, splicing (SMNDelta7), or germ-line mutations (e.g., Y272C), produce a proapoptotic form of SMN that may contribute to neuronal death in SMA and perhaps other neurodegenerative disorders.

Transforming growth factor-B3 protects murine small intestinal crypt stem cells and animal survival after irradiation, possibly by reducing stem-cell cycling.

Abstract: Damage to the normal replacing tissues of the body, specifically the gastro-intestinal tract, limits the treatment and hence, cure rate of cancer patients. Here, we investigate the possibility that the sensitivity of the gastro-intestinal tract can be manipulated by transforming growth factor β3 (TGF-β3), making it more resistant to radiation in a murine model. The effects of TGF-β3 were assessed using the crypt microcolony assay, a test of crypt stem-cell functional competence, in animal survival studies examining diarrhoea severity, labelling index and crypt size. Prior treatment with TGFβ3 can result in a 3- to 4-fold increase (protection factor, PF) in surviving crypts, whilst longer exposure can raise the PF to almost 12. Protection of intestinal clonogenic stem cells results in marked protection of survival with a corresponding reduction in the duration and level of diarrhoea and ultimate restoration of normal histology in surviving mice. Inhibition of proliferation can be demonstrated when sufficient TGF-β3 exposure is studied. Crypt size is also reduced. In conclusion, TGF-β3 protects small intestinal clonogenic stem cells from radiation damage, reducing diarrhoea and animal mortality. The mode of action is believed to be specific inhibition of stem-cell proliferation. Int. J. Cancer 86:53–59, 2000. © 2000 Wiley-Liss, Inc.

A Tropical Volcano, High Predation Pressure, and Breeding Biology of Arctic Waterbirds: A Circumpolar Review of Breeding Failure in the Summer of 1992

Abstract: Although periodic breeding failures of Arctic-nesting birds on a regional scale are common, a breeding failure encompassing almost the entire Arctic in the same year is exceptional. In the spring and summer of 1992, however, the aerosol cloud resulting from the 1991 eruption of Mount Pinatubo (Philippines) had reached the high northern latitudes and caused significant cooling in most of the Arctic, with widespread negative consequences for Arctic-breeding birds. At the same time, low abundance of small rodents and high abundance of predators presented additional problems for breeding birds in parts of the Palearctic. We compiled data on breeding biology of Arctic waterfowl and waders from more than 30 field studies to illuminate in what ways the circumpolar bad weather and predation influenced the breeding season of Arctic birds in 1992. Most projects reported a higher proportion of nonbreeders and a delayed onset of nest initiation compared to other years. Hatching and fledging success of the low number of late breeders was reduced. In addition, some projects reported lower clutch sizes and increased adult mortality. Detailed data from field studies are complemented by data on overall reproductive success of waterfowl and wader populations collected from staging and wintering grounds. In total, there was an almost complete reproductive failure for waders and waterfowl throughout the Arctic in 1992, suggesting a short-term effect on global waterbird populations. This is an example of climatic fluctuations influencing reproductive biology of a group of species on a circumpolar scale.

Muskoxen in Angujaartorfiup Nunaa, West Greenland: Monitoring, Spatial Distribution, Population Growth, and Sustainable Harvest

Abstract: In the 1960s, 27 muskoxen (Ovibos moschatus) were introduced to Angujaartorfiup Nunaa, which is located next to Kangerlussuaq Airport in West Greenland. Data from 12 aerial surveys of muskoxen from 1986 to 1996 show 1) that the population has stabilized at 3000 muskoxen since hunting was initiated in 1988, 2) that the population has maintained a high level of reproduction during the study period, and 3) that an annual kill of about 700 muskoxen will maintain the population at its current level if natural mortality and reproduction remain unchanged. Using a geographical information system to subdivide data by topography and altitude showed that muskoxen greatly favour valleys and lowland areas. Densities of muskoxen above 500 m above sea level were less than 51% of densities below 500 m above sea level.

The role of parasitic diseases as causes of mortality in cattle in a high potential area of central Kenya: a quantitative analysis.

Abstract: Postmortem records of cattle brought to the Veterinary School in Kabete near Nairobi were examined for a period of 15 years (1984-1998, inclusive) in order to establish the role that parasitic diseases played as causes of death. The cattle were mainly of exotic breeds but a few were crosses or of indigenous breeds. There was a total of 1413 cases of deaths from various diseases of which 177 (13%) were due to parasites. The tick-borne diseases were in high proportions and accounted for 84,7% among the parasitic causes, which represented 10,6% of all the deaths recorded. The main tick-borne disease was East Coast fever (ECF) (65%) followed by heartwater (10,2%), babesiosis (5,1%) and anaplasmosis (4,5%). Hydatidosis was responsible for 7,3% of deaths from parasitic causes. Deaths from ECF were recorded in all the 15 years and in high proportions compared to those due to heartwater (8/15), babesiosis (7/15) and anaplasmosis 5/15). Over the period under consideration, no decline was noted among various disease conditions despite advances made in controlling tick vectors and in the treatment of various parasitic conditions. The area covered by this study has the advantage of having several veterinary-related institutions close by. Hence knowledge and awareness about livestock diseases is relatively high compared to other parts of the country. It is therefore challenging to the Veterinary Department to examine the service delivery systems and other factors that may contribute to the persistent presence of these fatal parasitic conditions of cattle.

Diarrhées du chamelon en Mauritanie : résultats d'enquête

Abstract: In Mauritania, diarrheas among camel calves can occur a few weeks after birth and are of great concern to livestock breeders. According to them, they are solely responsible for camel calf mortality. Two surveys were conducted in order to determine diarrhea etiology and to assess ensuing losses: 1) in the Wilayas (in the South East of the country) as part of a survey on young animal mortality; 2) in Boghe (in the Center) in dromedaries. Calves with diarrhea and aged a few days to a year were surveyed. Diarrhea samples were collected in the field and stocked in ice or formaldehyde for bacteriological or parasitological examinations, respectively. The origins of the various etiologies (“etiological complex”) could be linked to: - Bacteria; Escherichia coli and Salmonella were among the bacteria responsible for enteritis; camel calves 0-3 months of age were the most affected; - Parasites; coccidia ( Eimeria cameli ) and gastrointestinal parasitic ( Haemonchus longistipes ) were found in all samples in particular in the rainy season; - Feed, or be unknown. These results corroborate those of other breeders who add to the etiology the mother health status, parturition period and phytoproducts used in agriculture