Contagious ecthyma, Biology

Contagious ecthyma
The contagious ecthyma virus is immunologically distinct from vaccinia, but similar  to the causative agent of pseudo-cow-pox. It belongs to the genus Parapoxvirus in the family Poxviridae. It affects lambs and kids of over 2 years old. The virus withstands drying and is capable of surviving at room temperature for at least 15 years. The disease occurs during dry season.  Recovered animals are solidly immune for 2 to 3 years, but no antibodies appear to be passed in the colostrum. Hence, newborn lambs of immune ewes are susceptible to this virus. In man, typical lesions occur at the site of infection. The lesions are very itchy and respond poorly to local treatment. The contagious ecthyma spreads rapidly in a flock through contact with affected animals or through inanimate objects.


Clinical signs:
The formation of papules and vesicles on the skin of the lips and sometimes on the nostrils and eyes is seen. These readily change to pustules and finally heavy scabs appear. The affected lambs or kids can neither suckle nor graze, which leads to rapid emaciation. Healing is usually complete in 1 month. The scabs fall off by this time leaving the lips smooth and without scars. Systemic invasion occurs rarely and lesions may extend down the alimentary tract as well as the trachea. In rams, lesions are present on the scrotal sac.


Diagnosis:
The lesions in the epithelium, viz. ballooning of cells leading to degeneration, vesicle formation and possible granuloma formations help in diagnosis. Inclusion bodies are absent. The isolation and identification of the virus in cell-cultures confirm the disease. The virus can be passaged in rabbits if large doses are placed on scarified skin or injected intradermally. Mild lesions develop on the chorio-allantois of 9-to 12-day-old chick embryos. Complement fixation and immunodiffusion tests are commonly used for diagnosis.Treatment, prevention and control: There is no specific treatment. Removal of the scabs and application of ointments or astringent lotions is practiced. The provision of soft and palatable food is recommended. In the early stages of outbreak, the affected animals should be isolated and the remainder animals vaccinated with 1% suspension of dried scabs in 50% glycerol saline by scarification on the inside of the thighs. Vaccinated animals develop a good grade of protection against the disease. Vaccination is of little value when a large number of animals are already affected. Persistence of the disease in a flock from year to year is common. The lambs should be vaccinated at 6 to 8 weeks of age. Vaccination is completely effective for at least 2 years, but the lambs should be inspected 1 week after vaccination to ensure that local reactions ('take') have resulted. The absence of a local reaction signifies lack of viability of the vaccine and consequent development of immunity. The immunity is not effective until
3 weeks after vaccination.

Posted Date: 9/18/2012 7:00:48 AM | Location : United States







Related Discussions:- Contagious ecthyma, Assignment Help, Ask Question on Contagious ecthyma, Get Answer, Expert's Help, Contagious ecthyma Discussions

Write discussion on Contagious ecthyma
Your posts are moderated
Related Questions
Define Sample Titration for Estimation of Vitamin c in Lemon Juice? Cut the lemon into two halves with a stainless steel knife. Remove the seeds. Squeeze the juice from half a

Coiling of garden pea tendrils around any support is an example of: 1. Thigmotaxis 2. Thigmonasty 3. Thigmotropism 4. Thermotaxis Thigmotropism

How sugar is used in Puddings, Sauces and Pie Fillings? When dry starch is added directly to a hot liquid, the particles on the outside tend to cook first, lumping the raw star

Define prevention of idd by Iodized Oil? The other approach employed as a specific measure for women and children in hyper-endemic areas is injection of iodized oil. Intramuscu

EGG S OF HEN It is a meiolecithal egg which is oval. The animal pole is found in the form of a small germinal disc. The vegital pole has two types of yolk viz. White yol

What are the functions of the Eyelids? Functions of the Eyelids: The eyelid makes the outer most layers, covering the eye. Because of its strategic position, the eyelid s

Define Measuring Direct Aerobic Fitness (VO 2 max) For direct measurement of VO, max, the subject is asked to perform exercise for 12 to 15 minutes. A stationary bicycle or a

Determine the extracellular concentration of TVA Consider Neuron B in the frog central nervous system whose plasma membrane has a previously unknown channel that is selectivel

Determine Nutritional Requirements for Space Missions? Space exploration represents a new frontier in the nutritional sciences and humans are eating in space since Cosmonaut Yu

Define the Concept of Health Care? We are aware of the fact that health is a fundamental human right. Thus, it becomes imperative for the State to assume responsibility for the