Dromedaries (Camelus dromedarius) are of Low Susceptibility to Inoculation with Foot-and-Mouth Disease Virus Serotype O

Two sheep and five dromedaries were inoculated with a highdose of a cattle-passaged type O strain of foot-and-mouth disease virus (FMDV). The sheep developed typical FMD. The inoculated camels, which were placed in contact with five further dromedaries and four sheep, showed no visible sign,,; of illness or vesicular lesions. However, one of them had a raised body temperature at 3 days post-inoculation (pi) and a viraemia from days 2 to 10; probang samples from this animal were negative for infections virus, but a low level of FMDV RNA was detected in a sample taken on day 6 pi, five other samples taken front days 3 to 28 being negative. Examination of mouth swabs indicated a low level of FMDV RNA at days 1-5 pi in four of the five inoculated camels, but no infectious FMDN7 or FMDV RNA was detected in serum, probang or month swab samples front contact-exposed animals (camels and sheep). All the contact-exposed camels and sheep and two of the inoculated camels were serologically negative for FMD when tested up to day 28. In contrast, the camel with viraemia became serologically positive front day 14, and the other two inoculated camels (which had been exposed to FMDV in an earlier experiment) became serologically positive from day 10. The experiment suggested that dromedaries (1) are of low susceptibility to FMDV serotype O, (2) do not transmit infection, even by close contact, and (3) are Unlikely to play a significant epidemiological role in FMD. (c) 2008 Elsevier Ltd. All rights reserved.