Poultry and duck diseases-marek''s disease, Biology

Marek's disease

Marek's disease is a lymphoproliferative disease of chicken, quails, bantams and other free-flying birds. It is caused by the Gallid Herpesvirus 2 of subfamily Alphaherpesvirinae in the family Herpesviridae. The presence of lymphomas in various visceral organs, nerves, gonands, skin and muscles constitute the clinical symptoms. The mortality rate varies from 10 to 15% in unvaccinated flocks. There are several strains of Marek's disease virus possessing varying degrees of oncogenicity. These are placed in two groups; Group 1 contains highly oncogenic strains and group 2 low or non - oncogenic strains. Among other factors influencing the pathogenesis of the disease are genetic resistance and age.

Clinical signs: Four overlapping syndromes are described. Neurolymphomatosis or classical Marek's disease is associated with an asymmetric paralysis of one or both legs or wings. Incoordination is a common early sign; one leg is held forward and the other backward. Wing dropping and lowering of head and neck are common.

Acute Marek's disease is common in explosive outbreaks with depression, ataxia and paralysis.Occular lymphomatosis leads to graying of iris of one or both eyes. Pupil is irregular and eccentric leading to  total or partial blindness. Cutaneous Marek's disease with round nodular lesions up to 1 cm in diameter are seen in feather follicles.


Diagnosis:
The disease is diagnosed by the isolation of the virus in embryonated eggs, chick kidney or duck embryo fibroblast culture using the living cells from buffy coat, spleen, tumor tissue or other lymphoid cells, skin and feather tips. The detection of viral antigens in non-lymphoid cells and Marek's associated tumor specific surface antigen (MATSA) in lymphoid cells is done by immunofluorescence in frozen tissue sections. Virus neutralization test is also used.


Prevention and control:
Three types of vaccines viz. Herpes virus of turkey (HVT),naturally occurring low pathogenic strains of Marek's disease virus (Serotype-2) and cell-culture attenuated MDV are available for immunization. Vaccine is available either a lyophilized cell free preparation or a cell associated preparation. Because of its economy in production, HVT vaccine is most widely used. One day old chicks are vaccinated parentrally.

Posted Date: 9/18/2012 8:23:57 AM | Location : United States







Related Discussions:- Poultry and duck diseases-marek''s disease, Assignment Help, Ask Question on Poultry and duck diseases-marek''s disease, Get Answer, Expert's Help, Poultry and duck diseases-marek''s disease Discussions

Write discussion on Poultry and duck diseases-marek''s disease
Your posts are moderated
Related Questions
What is Lactation? High levels of estrogens and progesterone during pregnancy stimulate the breasts to develop prior to lactation, or milk production. At the same time, levels

Conscious experience is probably the most familiar mental process that we know, yet its workings remain mysterious. Consciousness is not directly accessible for study. Hence the ne

Class Bivalvia Body in a bilohed mantle enclosed in a two-valved shell; head reduced; mouth with labial palps but no radula; foot wedge-shaped; plate-like gills; sexes separa

How is the nervous system of nematodes organized? Where are the neural chords located in their body? Roundworms have a ganglial nervous system with an anterior neural ring sho

Describe about The implant surgeon The implant surgeon should have basic knowledge of the macroscopic and microscopic anatomy of the jaw bones with their associated neurovascul

Classification of Different Agro-Industrial By-Products The agro-industrial by-products can be grouped according to the content of nutrients namely: (i) Energy rich supplem

What are the protective structures of the central nervous system present in vertebrates? In vertebrates the brain and the spinal cord are protected by membranes, the meninges,

What are the two main groups into which flowering plants are divided? Angiosperm plants are separated into a) Monocotyledonous (monocots) and b) Dicotyledonous (dicots

Q. Etiologic factor of ulcerative colitis? No single etiologic factor has been identified although genetic auto-immune factors are thought to be involved. Although exacerbation

Monosaccharides :- Sugars consisting of  a  single  polyhydroxy  aldehyde or ketone unit.