Showing papers on "Animal mortality published in 2006"

A secreted serine-threonine kinase determines virulence in the eukaryotic pathogen Toxoplasma gondii.

Abstract: Toxoplasma gondii strains differ dramatically in virulence despite being genetically very similar. Genetic mapping revealed two closely adjacent quantitative trait loci on parasite chromosome VIIa that control the extreme virulence of the type I lineage. Positional cloning identified the candidate virulence gene ROP18, a highly polymorphic serine-threonine kinase that was secreted into the host cell during parasite invasion. Transfection of the virulent ROP18 allele into a nonpathogenic type III strain increased growth and enhanced mortality by 4 to 5 logs. These attributes of ROP18 required kinase activity, which revealed that secretion of effectors is a major component of parasite virulence.

Anthrax in Western and Central African great apes

Abstract: During the period of December 2004 to January 2005, Bacillus anthracis killed three wild chimpanzees (Pan troglodytes troglodytes) and one gorilla (Gorilla gorilla gorilla) in a tropical forest in Cameroon. While this is the second anthrax outbreak in wild chimpanzees, this is the first case of anthrax in gorillas ever reported. The number of great apes in Central Africa is dramatically declining and the populations are seriously threatened by diseases, mainly Ebola. Nevertheless, a considerable number of deaths cannot be attributed to Ebola virus and remained unexplained. Our results show that diseases other than Ebola may also threaten wild great apes, and indicate that the role of anthrax in great ape mortality may have been underestimated. These results suggest that risk identification, assessment, and management for the survival of the last great apes should be performed with an open mind, since various pathogens with distinct characteristics in epidemiology and pathogenicity may impact the populations. An animal mortality monitoring network covering the entire African tropical forest, with the dual aims of preventing both great ape extinction and human disease outbreaks, will create necessary baseline data for such risk assessments and management plans.

Connectivity Conservation: Maintaining and restoring connectivity in landscapes fragmented by roads

Abstract: INTRODUCTION Transportation networks and systems are vital to today's economy and society (Button and Hensher 2001). Not only do roads provide for safe and efficient movement of goods and people across cities and continents, throughout the world they have become a permanent part of our physical, cultural, and social environment (Robinson 1971; Lay 1992). Roads and their networks are one of the most prominent human-made features on the landscape today (Sanderson et al . 2002). Compared to polygonal blocks of built areas, road systems are linear and etched into the landscape to form a woven network of arteries that maintain the pulse of societies. However, as road networks extend across the landscape and their weave intensifies, natural areas become increasingly fragmented and impoverished biologically (Forman et al . 2003). Although less studied compared to other agents of fragmentation, roads cause changes to wildlife habitat that are more extreme and permanent than other anthropogenic sources of fragmentation (Forman and Alexander 1998; Spellerberg 2002). Road networks and systems not only cause conspicuous changes to physical landscapes, but also alter the patterns of wildlife and the general function of ecosystems within these landscapes (Swanson et al . 1988; Transportation Research Board 1997; Olander et al . 1998). Busy roads can be barriers or filters to animal movement (Hels and Buchwald 2001; Rondinini and Doncaster 2002; Chruszcz et al . 2003) and in some cases the leading cause of animal mortality (Maehr et al . 1991; Jones 2000; Kaczensky et al . 2003).

Efficacy of a herbal product against Histomonas meleagridis after experimental infection of turkey poults

Abstract: Histomoniasis (infectious enterohepatitis, blackhead) is caused by the protozoan parasite Histomonas meleagridis (H. meleagridis). After the ban of all prophylactic and therapeutic drugs in the European Union, histomoniasis is increasingly responsible for considerable economic problems to the poultry industry. The aim of this study was to investigate the effect of a herbal product with extracts from cinnamon, garlic, lemon, and rosemary on H. meleagridis in turkey poults in vivo. For this purpose, 60 two-week-old poults were divided into three groups. Group 1 received the herbal product in the feed six days before infection and in water three days before infection, then in feed and drinking water until the end of the experiment. Groups 2 and 3 were left untreated. At week 3 of age, Groups 1 and 2 were infected intracloacally with H. meleagridis. Three weeks after infection the surviving birds were euthanized and examined for pathological lesions. Mortality was 20% in Group 1 and 50% in Group 2. There were no deaths in Group 3. DNA of histomonads was detected in all examined caeca and livers of the dead birds, but was not detected in any examined organ of the surviving birds of all groups. There was no noticeable difference in the lesion scores of the dead birds between the groups. The surviving birds of all groups did not show lesions post mortem. Since all effective prophylactic and therapeutic drugs against histomoniasis were banned in the EU, under given conditions the investigated herbal product seems to be an effective alternative for the reduction of mortality in turkeys caused by histomoniasis.

Toxicity and biodistribution of a first-generation recombinant adenoviral vector, encoding aquaporin-1, after retroductal delivery to a single rat submandibular gland.

Abstract: Before conducting a phase 1/2 clinical trial of a serotype 5 adenovirus encoding human aquaporin-1 (AdhAQP1) for the treatment of radiation-damaged salivary glands, we have conducted a detailed toxicity and biodistribution study in adult rats. AdhAQP1 (2 × 108–2 × 1011 particles) was delivered to a single submandibular gland by retroductal cannulation. Administration of this vector resulted in no animal mortality or morbidities, and no adverse signs of clinical toxicity. In addition, over the 92-day time course of the study, with both male and female rats, there were no consistent treatment-related changes in serum indicators of hepatic, renal, and cardiac functions. Importantly, we also observed no vector-associated effects on either water consumption by, or hematocrit levels in, study animals. However, three suggestive mild gender-related response differences were seen. Female, but not male, rats exhibited small reductions in food consumption (∼10–15%) and body weight gain (5–10%), and evidence of persi...

Pre-exposure to a novel nutritional mixture containing a series of phytochemicals prevents acetaminophen-induced programmed and unprogrammed cell deaths by enhancing BCL-XL expression and minimizing oxidative stress in the liver.

Abstract: From a disease-prevention perspective, recent progress in phytochemical and nutraceutical research clearly suggests (benefits outweigh the risk pattern). Although powerful antioxidant properties have been the most acclaimed mechanism of action for these entities, the individual antioxidants studied in clinical trials do not appear to have consistent preventative effects. The actions of the antioxidant nutrients alone do not explain the observed health benefits of diets rich in fruits and vegetables for chronic diseases. Therefore, we proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for these potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in plants [1]. Surprisingly, however, no studies have attempted to evaluate the combined antitoxic potential of a phytochemical-nutraceutical mixture (PNM) in in vivo models. Therefore, this study, for the first time, was designed to investigate whether pre-exposure to a unique PNM has the ability to impede mechanistic events involved in acetaminophen (APAP)-induced hepatotoxicity. Besides several vitamins and minerals in balanced proportions (~US RDA), the PNM used in this investigation contained several well-known phytochemicals such as citrus flavonoids, red wine polyphenols, Garcinia, Gymnema, Ginkgo, Ephedra sinica, Camelia sinensis, Silybum, Guarana, Eluthero, Allium sativum and Ocimum basilicum extracts. To evaluate PNM's antitoxic potential, groups of animals ICR mice, 3 months old) received either a control diet or PNM containing diets (1X and 10X) for 4 weeks. On day-28, animals were divided into two subgroups. Half the animals were administered normal saline and the other half received 400mg/kg ip injections of APAP. All the animals were sacrificed 24h after APAP exposure. Serum and tissue (liver and kidneys) samples were analyzed. APAP alone caused massive liver injury (nearly 495-fold increase in ALT) and oxidative stress (Lipid peroxidation: 268% increase in MDA) coupled with genomic DNA fragmentation (288% increase). Exposure to 1X-PNM for 28 days significantly reduced animal mortality and all the APAP-induced biochemical events (In 1X-PNM + AP: ALT leakage decreased to 54 fold; MDA accumulation decreased to 125%, and DNA fragmentation decreased to 122%), whereas 10X-PNM + APAP slightly escalated both oxidative stress and genomic DNA fragmentation preceding liver injury. Liver homogenates subjected to western blot analysis disclosed the ability of 1X-PNM to counteract APAP-induced decrease in Bcl-xL expression. Histopathological evaluation of stained liver tissue sections indicated anti-apoptogenic and anti-necrogenic reponses coupled with near complete prevention of glycogen depletion by 1X-PNM. Collectively, our investigation suggests that a mixture containing an assortment of phytochemicals/nutraceuticals may serve as a much more powerful blend in preventing drug or chemical-induced organ injuries than a single phytochemical or nutraceutical entity. In addition, ephedra and caffeine containing PNM-exposure in a controlled manner may potentially shield vital target organs from toxicities caused by intentional, unintentional or accidental exposures to structurally and functionally diverse drug and chemical entities.

Transvascular dissemination of Porphyromonas gingivalis from a sequestered site is dependent upon activation of the kallikrein/kinin pathway

Abstract: Background and Objective: Epidemiological evidence implicates a connection between human periodontitis and systemic diseases. One possible mechanism involves the direct dissemination of periodontopathogens to the target organs through the circulation. The aim of this work was to define the mechanism used by Porphyromonas gingivalis for dissemination from a sequestered infection site. Material and Methods: BALB/c mice were subcutaneously infected with P. gingivalis via use of a mouse chamber model. Tissue fluids from various sites were collected and cultured to determine the presence of P. gingivalis. Evans Blue dye was used to measure the dissemination ability of P. gingivalis. Kinin-associated molecules were introduced into mice, and their effects on bacterial dissemination and mouse pathology were monitored. Results: P. gingivalis strain A7436 caused remote lesions and septicemia with severe cachexia, resulting in animal death. Intrachamber challenge with A7436 resulted in vascular permeability enhancement (VPE), as measured by the systemic infiltration of Evans Blue dye into chamber fluids. VPE was blocked by kininase and kinin receptor antagonist and enhanced by exogenous bradykinin and kininase inhibitor. Live bacteria were recovered from the subcutaneous perichamber and abdominal spaces (spreading), and from the blood (disseminating) of infected mice. Both kininase and kinin receptor antagonist reduced animal mortality as a result of infection with strain A7436 and decreased the number of bacteria recoverable from the blood, but they were not associated with bacterial spreading. Conclusions: The results suggest that activation of the kinin system is involved in the breach of the vascular barrier that permits dissemination of P. gingivalis.

RESEARCH ARTICLE Anthrax in Western and Central African Great Apes

Abstract: During the period of December 2004 to January 2005, Bacillus anthracis killed three wild chimpanzees (Pan troglodytes troglodytes) and one gorilla (Gorilla gorilla gorilla) in a tropical forest in Cameroon. While this is the second anthrax outbreak in wild chimpanzees, this is the first case of anthrax in gorillas ever reported. The number of great apes in Central Africa is dramatically declining and the populations are seriously threatened by diseases, mainly Ebola. Nevertheless, a considerable number of deaths cannot be attributed to Ebola virus and remained unexplained. Our results show that diseases other than Ebola may also threaten wild great apes, and indicate that the role of anthrax in great ape mortality may have been underestimated. These results suggest that risk identification, assessment, and management for the survival of the last great apes should be performed with an open mind, since various pathogens with distinct characteristics in epidemiology and pathogenicity may impact the populations. An animal mortality monitoring network covering the entire African tropical forest, with the dual aims of preventing both great ape extinction and human disease outbreaks, will create necessary baseline data for such risk assessments and management plans. Am. J. Primatol. 68:928–933, 2006. c 2006 Wiley-Liss, Inc.

A three-dimensional Thermal Model for McNary Dam

Abstract: Water temperature is an important water quality parameter in aquatic ecosystems, impacting dissolved oxygen, chemical and biological reaction rates, and plant and animal mortality. In particular, during summer months, high temperatures in the forebay, gatewells and juvenile fish collection channel at McNary Dam lead to increased stress on fish population. A 3D hydrodynamic and heat transport model was developed to predict the water temperature on McNary Dam. The flow field was solved using an incompressible RANS solver for buoyant flows. The Boussinesq approach and a standard k � � model with wall functions were employed. The thermal model takes into account the energy sources due to solar radiation and the convective heat transfer at the free surface, which is function of the air temperature and wind velocity. The equations of the proposed thermal model were implemented into the commercial code FLUENT. The unsteady energy sources, boundary conditions at the free surface and inflows were programmed. A calibration for a typical day was conducted using measured temperature profiles and weather conditions. Comparison shows that the model reproduced general observed trends and daily fluctuations. The multidimensional temperature and velocities fields are presented and discussed.

Dysfunction of ionic channels in cardiomyocyte sarcolemma and cardiac arrhythmias.

Abstract: The arrhythmic effects of Na+ and Ca2+ intracellular imbalance were examined on rats with aconitine-induced cardiac arrhythmias. Under conditions of Na(+)-dependent arrhythmogenesis, blockade of Ca(2+)-channels with verapamil aggravated cardiac rhythm disturbances. Correction of ionic imbalance by intravenous injection of calcium preparations in aconitine-induced arrhythmia promoted recovery of stable sinus rhythm and decreased animal mortality. Intracellular imbalance of Na+ and Ca2+ ions can underlie the arrhythmogenic effects of antiarrhythmic drugs.

Limited myocardial muscle necrosis model allowing for evaluation of angiogenic treatment modalities.

Abstract: The currently accepted model for creating infarcted cardiac tissue in a rat model involves ligation of the left anterior descending artery (LAD), either proximally or at the bifurcation level. This procedure requires significant technical expertise and, even in skilled hands, commonly results in a 30% to 60% animal mortality. The authors propose a new model for creating a limited area of myocardial muscle necrosis that can be effectively studied. It involves a distal electrocautery occlusion of the LAD terminal branches and coagulation of the surrounding muscle. The model is consistently reproducible and decreases the morbidity of the study animals. It provides a cardiac muscle necrosis model not dependent on survival, while allowing study of the post injured state of the muscle and surrounding scar. This allows researchers to evaluate neovascularization and healing of the scar and peri-necrotic muscle, to assess improving blood flow with treatment by techniques designed to improve and stimulate angiogenesis, and to measure the outcome of stem-cell transplants for potential clinical use.