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
Amoebae- Parasitic Protozoan The amoebae of the genus Entamoeba vary in their biology. Entamoeba histolytica or the dysentery amoeba occurs as a parasite in the large intestin

what are enzymes

Describe about the term - Bacterial Infections Bacterium is a loose generic name for any microorganism (typically one celled) that has no chlorophyll and multiplies by simple d

What are the main substances transferred from the mother to the fetus through the placenta? And from the fetus to the mother? From the mother to the fetus the major transferre

Chart of taxonomy of animal viruses

What type of bonds is susceptible to hydrolysis? Book examples are C-N and C-OH.

Define hexose monophosphate pathway The hexose monophosphate pathway (HMP also called the pentose phosphate pathway, or phoshogluconate pathway) consists of Mo irreversible o

Scaling Instrumentation of prothesis Although stainless steel is generally the most effective material for removing calculus, it cannot be used with implants, because it scratc

Suspensor - Pollen Biology The structure and function of suspensor have not been given adequate attention. During the last decade, however, investigations have produced notewo

This is the amount of blood that is returned to the heart by the veins. This is influenced by various factors. Inspiration decreases the pressure in the  central veins and thus inc