Contagious pustular dermatitis (orf) infection in sheep and goats in Saudi Arabia

Contagious ecthyma: how serious is the disease worldwide?

Contagious ecthyma (CE) is an infectious disease of small ruminants caused by a parapoxvirus of family Poxviridae subfamily Chordopoxvirinae. The disease is obviously distinguished by an establishment of scabby lesions and ulcerative formation on less hairy areas including muzzle, ears, nostril, and sometimes on genitalia. The disease is endemic in sheep and goats. The virus is transmissible to other ruminants and is a public health concern in humans. Although the disease is known as self-limiting, it may cause a significant economic threat and financial losses due to lower productivity in livestock production. Information with regard to the risk of the disease and epidemiology in most parts of the world is underreported. This paper aims to provide relevant information about the epidemiology of CE in selected regions of Europe, South America, North America, Asia, Africa, and Australia. An in-depth comprehension of virus infection, diagnoses, and management of the disease will enable farmers, researchers, veterinarians, abattoir workers, health personnel, and border controllers to improve their measures, skills, and effectiveness toward disease prevention and control, toward reducing unnecessary economic loss among farmers. A herd health program for significant improvement in management and productivity of livestock demands a well planned extension program that ought to encourage farmers to equip themselves with adequate skills for animal healthcare.

Comparative study on three locally developed live orf virus vaccines for sheep in Saudi Arabia

The epidemiology of orf virus infection in Saudi Arabia (SA) has been researched since 1990. The results obtained during this period indicate that the disease is widespread, has great economic impact and that no vaccine has been used against it. The present study compares the immunogenicity and protective efficacy of three locally developed live orf virus vaccines. Two of them differ in their passage history in Vero cell culture and the third was used as a virulent virus in glycerine buffer. To the best of the authors’ knowledge, no similar comparative study has been conducted in the Middle East utilising three types of vaccines prepared from the same virus strain. Selection of the candidate seed orf virus and performance of the quality control tests were as laid out by the OIE for veterinary vaccine production. The vaccine seed virus was a field orf virus isolated from a previous orf outbreak in Saudi Arabia. A simple novel formula was developed to calculate the rate of reduction in the healing time (RHT %) in the challenged sheep. This allowed direct comparison of the efficacy of the three types of vaccines employed in the present study. The efficacy of each vaccine was tested on a cohort of local Noemi sheep.

Severe long-lasting contagious ecthyma infection in a goat's kid

In this report we describe an unusual orf infection in a goat's kid, which lasted for 6 months. The disease was reproduced in two susceptible goat kids, which both completely recovered within 37 days. Further clinical observations on these kids for 12 months did not reveal any signs of orf disease. The orf virus was isolated and identified from the animals which were involved in the original outbreak, from the kid that showed the long-lasting disease and from the experimentally-infected kids. The situation is discussed.

A close comparative study on the response of sheep and goats to experimental orf infection

A comparative experimental study of the clinico-pathological and serological response of sheep and goats to orf infection was made. All infected animals depicted typical orf lesions and seroconverted. The clinical, serological, gross and histopathological responses were similar in both species. However, the disease span was longer in sheep than in goats. It was concluded that sheep could play an important role in maintenance of the virus in the environment.

Sero-surveillance for orf antibodies in sheep and goats in Saudi Arabia employing the ELISA technique

A serological survey was conducted on sheep and goats in Saudi Arabia to detect humoral antibodies against the orf virus. The ELISA technique was superior to the AGID and CFT in detecting such antibodies. Of the 239 abattoir serum samples examined, 60 per cent had orf antibodies by ELISA while 94.8 per cent of the convalescent sera had antibodies detectable by ELISA. With the lack of vaccination and the reports that the clinical disease is commonly seen in different parts of the Kingdom, it may be that orf is becoming enzootic in this country. Recommendations for implementing a satisfactory vaccination regimen are given.