Susceptibility of Moroccan sheep and goat breeds to peste des petits ruminants virus

Peste des petits ruminants (PPR) is a highly contagious viral disease of small ruminants in Asia and Africa. In 2008, a PPR outbreak was reported for the first time in Morocco and a mass vaccination campaign allowed control of the disease. In this study, the susceptibility of four Moroccan local breeds of small ruminants to PPR virus was investigated by experimental infections. The objective was to make recommendations for improved epidemiological surveillance in Morocco by evaluating the susceptibility of the dominant Moroccan small ruminant breeds. Three parameters were studied: hyperthermia, clinical scoring and virus excretion. The outcome was compared to Alpine goats, which are considered one of the most sensitive breeds.

The study showed that the local goat breed was the most sensitive breed with a susceptibility rate of 67%, followed by Timahdit, Beni Guil and Sardi sheep with 48, 29 and 26%, respectively. Serological testing including enzyme-linked immunosorbent assay and viral neutralization showed that the Timahdit breed developed a stronger antibody response compared to the other breeds. Although the clinical signs observed in the sheep were mild, evidence of viral excretion was detected by means of a polymerase chain reaction assay.

It is recommended that effective surveillance should focus on susceptible breeds complemented with serological surveillance of the sheep population.