Johne''s disease, Biology

Johne's disease

It is also known as paratuberculosis characterized by chronic enteritis and progressive weakness in dairy animals.

Etiology: Mycobacterium paratuberculosis, the causative organism for this chronic disease, is an acid fast and comparatively resistant bacillus. The principal mode of spread of disease is through ingestion of contaminated feed or water or through intrauterine route. Morbidity rates are high but mortality is only 1-10% and main losses result from reduced production or weight gain.

Pathogenesis: Organisms localize in the intestinal mucous membrane and adjoining lymph nodes and multiply there.

Clinical signs: In cows, there is reduced milk production, progressive weight loss and submandibular edema. There is diarrhoea and faeces resemble pea soup and are without offensive odour. Feed intake remains normal but water intake is increased. In sheep and goats, faeces are soft but diarrhoea is usually not seen. The animals show progressive weakness and alopecia. In goats depression and dyspnoea are additional signs.

Diagnosis: It is diagnosed by clinical signs and history of persistent diarrhoea and continuous but slow weight loss. It can be confirmed by performing intra-dermal Johnin test. Johnin PPD 0.2 ml is injected by intra-dermal route in the cervical region. In positive cases, skin thickness at injected site increases by 3 mm or more by 48 to 72 h. Faecal or rectal pinch examination also confirms the disease. Serological tests like indirect fluorescent antibody, ELISA and complement fixation tests are also confirmatory. The organisms can be grown from faecal samples. However, none of these tests taking one at time can detect all the cases of paratuberculosis, so 2 or 3 tests are performed for its diagnosis. The advanced clinical cases can be diagnosed easily by clinical symptoms, faecal examination and antibody response of the host while preclinical cases can be detected by lymphocyte transformation, antibody response and faecal examination. Resistant animals can only be diagnosed by lymphocyte transformation test.

Treatment: The treatment is difficult as organisms are mostly resistant to antibiotics and it requires prolonged treatment. There is some recovery, if animals are treated with streptomycin @ 50 mg/kg body weight for 20-30 days. Combination of 500 mg dihydrostreptomycin intramuscularly and 300 mg- each of rifampin and isoniazied given twice daily orally were found effective in goats.

Control: The long incubation period and lack of single diagnostic test makes the disease difficult to control. Eradication of infected animals and carriers and maintenance of strict hygienic conditions are of some value. An animal herd may be declared free of paratuberculosis only when they do not show symptoms up to 3 years, feacal culture of above 2-year-old animals is negative and Johnin testing gives negative results.

Posted Date: 9/19/2012 1:37:19 AM | Location : United States







Related Discussions:- Johne''s disease, Assignment Help, Ask Question on Johne''s disease, Get Answer, Expert's Help, Johne''s disease Discussions

Write discussion on Johne''s disease
Your posts are moderated
Related Questions
Tuberculosis Tuberculosis is caused by a Bacillus-mycobacterium tuberculosis, a gram- positive and acid-fast organism. It is communicable disease. Mode of Transmissio

Explain the Bioavailability of Vitamin E? For dietary purposes, vitamin E activity is expressed as a-tocopherol equivalents (a-TEs). One α-TE is the activity of l mg α-tocophe

Absorption of amino acids and  peptides Generally,  the  dietary proteins are almost comp!etely  digested to their constituent amino acids and these are rapidly absorbed  from

Explain circulatory support and types of shock? CIRCULATORY SUPPORT 1) A "shock" state is characterised by hypoperfusion of tissue and cellular hypoxia. Circulatory suppo

What is the difference between recessive allele and dominant allele? The Dominant allele is the allele that determines phenotypical features that manifest in heterozygous or ho

How many distinct hexapeptides can be made from 20 amino acids?

Q. How different are fecundation in chondrichthyes and in osteichthyes? In chondrichthyes fecundation is internal by resources of copulation. In osteichthyes fecundation genera

The heart is enclosed in a membranous sac called the pericardium. It has two layers- the fibrous pericardium which is the outer layer and the serous pericardium that lies inside th

Define about the Centrifuge? Centrifuge is an apparatus consisting essentially of a compartment spun about a central axis to separate contained materials of different specific

Hormon e . The chief cells of the parathyroids secrete a hormone called parathyroid hormone (PTH) or parathormone or also called Collip's hormone after the name of its discove