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Threshold Host Density
Threshold host density (NT), in the context of wildlife disease ecology, refers to the concentration of a population of a particular organism as it relates to disease. Specifically, the threshold host density (NT) of a species refers to the minimum concentration of individuals necessary to sustain a given disease within a population. Threshold host density (NT) only applies to density dependent diseases, where there is an "aggregation of risk" to the host in either high host density or low host density patches. When low host density causes an increase in incidence of parasitism or disease, this is known as inverse host density dependence, whereas when incidence of parasitism or disease is elevated in high host density conditions, it is known as direct host density dependence. Host density independent diseases show no correlation between the concentration of a given host population and the incidence of a particular disease. Some examples of host density independent diseases are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wildlife Disease
Wild animals, domestic animals and humans share a large and increasing number of infectious diseases, known as zoonoses. The continued globalization of society, human population growth, and associated landscape change further increase the interactions between humans and other animals, thereby facilitating additional infectious disease emergence. Contemporary diseases of zoonotic origin include SARS, Lyme disease and West Nile virus. Disease emergence and resurgence in populations of wild animals are considered an important topic for conservationists, as these diseases can affect the sustainability of affected populations and the long-term survival of some species. Examples of such diseases include chytridiomycosis in amphibians, chronic wasting disease in deer, white-nose syndrome, in bats, and devil facial tumour disease in Tasmanian devils. Prevention Culling Disease outbreaks in wild animals are sometimes controlled by killing infected individuals to prevent transmission ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Immunodeficiency Virus
The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause AIDS, acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Without treatment, average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype. In most cases, HIV is a sexually transmitted infection and HIV/AIDS#Transmission, occurs by contact with or transfer of blood, pre-ejaculate, semen, and Vaginal lubrication, vaginal fluids. Non-sexual transmission can occur from an infected mother to her infant during pregnancy, during childbirth by exposure to her blood or vaginal fluid, and through breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected White blood cell, immune cells. Research has shown (for both same-sex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemiology
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic epidemiology, occupational epidemiology, screening, biomonitoring, and comparisons of treatment effects such as in clinical trials. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conservation Biology
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management. The conservation ethic is based on the findings of conservation biology. Origins The term conservation biology and its conception as a new field originated with the convening of "The First International Conference on Research in Conservation Biology" held at the University of California, San Diego in La Jolla, California, in 1978 led by American biologists Bruce A. Wilcox and Michael E. Soulé with a group of leading university and zoo researchers and conservationists including Kurt Benirschke, Sir Otto Frankel, Thomas Lovejoy, and Jared Diamond. The meeting was prompted due to concern over tropical deforestation, disappearin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disease Ecology
Disease ecology is a sub-discipline of ecology concerned with the mechanisms, patterns, and effects of Host–pathogen interaction, host-pathogen interactions, particularly those of infectious diseases. For example, it examines how Parasitism, parasites spread through and influence wildlife populations and communities. By studying the flow of diseases within the natural environment, scientists seek to better understand how changes within our environment can shape how pathogens, and other diseases, travel. Therefore, diseases ecology seeks to understand the links between Biological interaction, ecological interactions and disease evolution. New emerging and re-emerging infectious diseases (infecting both wildlife and humans) are increasing at unprecedented rates which can have lasting impacts on public health, ecosystem health, and biodiversity. Factors affecting spread of diseases Parasitic infections, along with certain transmitted diseases, are present in wildlife which can hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simian Immunodeficiency Virus
''Simian immunodeficiency virus'' (''SIV'') is a species of retrovirus that cause persistent infections in at least 45 species of non-human primates. Based on analysis of strains found in four species of monkeys from Bioko Island, which was isolated from the mainland by rising sea levels about 11,000 years ago, it has been concluded that SIV has been present in monkeys and apes for at least 32,000 years, and probably much longer. Virus strains from three of these primate species, SIVsmm in sooty mangabeys, SIVgor in gorillas and SIVcpz in chimpanzees, are believed to have crossed the species barrier into humans, resulting in HIV-2 and HIV-1 respectively, the two HIV viruses. The most likely route of transmission of HIV-1 to humans involves contact with the blood of chimps and gorillas that are often hunted for bushmeat in Africa. Four subtypes of HIV-1 (M, N, O, and P) likely arose through four separate transmissions of SIV to humans, and the resulting HIV-1 group M strain most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history. Ecology is a branch of biology, and it is not synonymous with environmentalism. Among other things, ecology is the study of: * The abundance, biomass, and distribution of organisms in the context of the environment * Life processes, antifragility, interactions, and adaptations * The movement of materials and energy through living communities * The successional development of ecosystems * Cooperation, competition, and predation within and between species * Patterns of biodiversity and its effect on ecosystem processes Ecology has practical applications in conservation biology, wetland management, natural resource managemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptospirosis
Leptospirosis is a blood infection caused by the bacteria ''Leptospira''. Signs and symptoms can range from none to mild (headaches, muscle pains, and fevers) to severe ( bleeding in the lungs or meningitis). Weil's disease, the acute, severe form of leptospirosis, causes the infected individual to become jaundiced (skin and eyes become yellow), develop kidney failure, and bleed. Bleeding from the lungs associated with leptospirosis is known as severe pulmonary haemorrhage syndrome. More than ten genetic types of ''Leptospira'' cause disease in humans. Both wild and domestic animals can spread the disease, most commonly rodents. The bacteria are spread to humans through animal urine, or water and soil contaminated with animal urine, coming into contact with the eyes, mouth, nose or breaks in the skin. In developing countries, the disease occurs most commonly in farmers and low-income people who live in areas with poor sanitation. In developed countries, it occurs during heavy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinococcus Multilocularis
''Echinococcus multilocularis'' is a small cyclophyllid tapeworm found extensively in the northern hemisphere. ''E. multilocularis,'' along with other members of the ''Echinococcus'' genus (especially '' E. granulosus''), produce diseases known as echinococcosis. Unlike ''E. granulosus,'' ''E. multilocularis'' produces many small cysts (also referred to as locules) that spread throughout the internal organs of the infected animal. The resultant disease is called Alveolar echinococcosis, and is caused by ingesting the eggs of ''E. multilocularis.'' The parasite is commonly maintained in a wildlife life cycle involving two mammalian hosts. Wild canids, dogs, and less commonly cats act as definitive hosts, harbouring the adult stage of the tape worm. Voles are the intermediate hosts. Ingestion of a rodent containing alveolar hydatid cysts by a wild canid can result in a heavy infestation of tapeworms. Signs and symptoms Human alveolar echinococcosis is characterized by a length ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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