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
Transposable elements are able to move around the genome by precise or imprecise excision events. What is meant by imprecise excision? A. Imprecise excision refers to a transpo

Q. Different stages involved in feeding patient - peptic ulcer? Stage I: It is characterized by haematemesis (vomiting of blood which may be derived from mouth, stomach, oesoph

PINEAL GLAND (EPIPHYSIS CEREBRI) - It develops from the ectoderm of the embryo. The pineal gland is located between the cerebral hemispheres, where it protrudes from the

Q. What are the respective functions of the separation of homologous chromosomes and of the separation of alike chromatids in meiosis? The separation of homologous chromosomes

What are the Benefits of migration Eg: Need to leave Alaska due to harsh weather conditions (statement that birds are escaping NZ winter not acceptable). Longer day

What is Lymphatic Network? The lymphatic network consists of the lymphatic vessels, which circulate lymph throughout the body. Lymph is a liquid which carries out exchange of g

what is reproductive system? what is urinary System? What is Nervous system

merits and demerits system of classification by Linnaeus

PHYLUM  MOLLUSCA Definition  and Introduction Basically bilateral and protostomial eucoelomate  eumetazoans  whose soft body (L. Millis  or molluscum= soft) is unsegmente

List structures found in unicellular organisms that are an adaptation to their free-living life and are not usually found in the cells of multicellular organisms.