Newcastle disease
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Newcastle disease is a highly contagious zoonotic bird disease affecting many domestic and wild avian species. Its effects are most notable in domestic poultry due to their high susceptibility and the potential for severe impacts of an epidemic on the poultry industries. It is endemic to many countries.
Newcastle Disease was discovered in Newcastle upon Tyne, England in 1926 (Doyle), but also at this time slightly different strains were found in other parts of the world.
Exposure of humans to infected birds (for example in poultry processing plants) can cause mild conjunctivitis and influenza-like symptoms, but NDV otherwise poses no hazard to human health. Interest in the use of NDV as an anticancer agent has arisen from the ability of NDV to selectively kill human tumour cells with limited toxicity to normal cells.
No treatment for NDV exists, but the use of prophylactic vaccines and sanitary measures reduces the likelihood of outbreaks.
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[edit] The causal agent
[edit] Description
The causal agent, Newcastle disease virus (NDV), is a negative-sense single-stranded RNA virus. Transmission occurs by exposure to faecal and other excretions from infected birds, and through contact with contaminated feed, water, equipment and clothing.
[edit] Strains
NDV strains can be categorised as velogenic (highly virulent), mesogenic (intermediate virulence) or lentogenic (nonvirulent). Velogenic strains produce severe nervous and respiratory signs, spread rapidly and cause up to 90% mortality. Mesogenic strains cause coughing, affect egg quality and production and result in up to 10% mortality. Lentogenic strains produce mild signs with negligible mortality.
[edit] Newcastle disease variant
In 1999, promising results were found using the Newcastle virus in cancer patients.[1] In 2006 researchers from the Hebrew University have succeeded in isolating a variant of the Newcastle Disease Virus (NDV-HUJ), in order to specifically target cancer cells [1]. NDV-HUJ is a natural variant of NDV Virus and is also an attenuated variant (e.g., weakened virus), it innately preferentially targets and replicates in certain types of tumor cells (brain and lung), leaving normal cells almost unaffected. The researchers tested the new Viro-therapy on 14 Glioblastoma multiforme patients and achieved promising results for the first time.
[edit] Use as a biological weapon
Newcastle disease was one of more than a dozen agents that the United States researched as potential biological weapons before the nation suspended its biological weapons program.[2]
[edit] Disease features in poultry
- See :here
[edit] Epidemiology
[edit] Clinical Symptoms
Signs of infection with NDV vary greatly depending on factors such as the strain of virus and the health, age and species of the host.
They can include respiratory signs (gasping, coughing), nervous signs (depression, inappetence, drooping wings, paralysis), swelling of the eyes and neck, diarrhoea, misshapen, rough- or thin-shelled eggs and reduced egg production.
[edit] Postmortem lesions
you can find petcheal haemorraige at provenriculus petcheal heamorriage at legs at tachea
[edit] Diagnosis
[edit] Prevention
Any animals that are showing symptoms of Newcastle Disease should be quarantined immediately. New birds should also be vaccinated before being introduced to your flock.
[edit] References
- Nelson CB, Pomeroy BS, Schrall K, Park WE, Lindeman RJ. (1952). An outbreak of conjunctivitis due to Newcastle disease virus (NDV) occurring in poultry workers. Am J Public Health 42(6):672–8.
[edit] Footnotes
- ^ PMID 10216468
- ^ "Chemical and Biological Weapons: Possession and Programs Past and Present", James Martin Center for Nonproliferation Studies, Middlebury College, April 9, 2002, accessed November 14, 2008.
[edit] External links
- World Organisation for Animal Health (OIE)
- Department of Environment, Food and Rural Affairs, UK
- CSIRO, Australia
- NDV-HUJ variant discovered by researchers from the Hebrew University - An IsraCast article
- United States Animal Health Association VELOGENIC NEWCASTLE DISEASE [2]
- Iowa State University Department of Veterinary Pathology, Center for Food Security and Public Health, "Newcastle Disease" [3]
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