Veterinary Medicine Extension¹, School of Veterinary Medicine, University of California Davis and California Animal Health and Food Safety System², Tulare, CA.

Following the outbreaks in the UK and the EU countries, much attention has been focused on Foot-and-Mouth Disease. It is one of the diseases frequently mentioned in discussions of foreign animal diseases that might be used in agro-terrorism. While this is a possibility, livestock owners and veterinarians would quickly recognize this disease due to all the recent public attention and the unusual characteristics of FMD such as blisters on the mouth, feet and teats. Rinderpest, on the other hand, is relatively unheard of by most US livestock owners and not high up on the list of potential diseases routinely considered by veterinarians. In addition, this highly infectious, viral disease of cattle is not readily distinguishable from some forms of Bovine Virus Diarrhea, BVD that often occurs in the US. For this reason, Rinderpest might go undetected in the US livestock population for some time before being discovered.

Rinderpest or cattle plague as it is commonly called in the Middle East, Asia, Africa or India, is caused by a virus and is highly contagious. This virus is closely related to the dog distemper virus and human measles virus. Although there is thought to be only one serotype of the virus, there are many strains of the virus causing a variable set of clinical expressions. The virus is fragile and is usually inactivated in the environmental by heat and putrefaction. Under conditions of high humidity and low temperatures it can remain viable for several days leading to possible new animal infections. It is also inactivated in processed meats.

Sick animals can shed the virus 1 to 2 days prior to showing overt clinical signs and rapidly transfer the virus to susceptible animals through virus-laden secretions especially nasal discharges. These discharges contain large quantities of virus during the early stages of infection. Contaminated equipment, clothing, buildings and vehicles remain sources of infection for only a short period of time. However, under appropriate environmental conditions, heavily contaminated vehicles may transfer the virus to other farms. Recovered animals do not remain carriers of the virus and are not a threat to spread the disease.

Clinically, Rinderpest is characterized by sudden onset, high fever, severe diarrhea, going off feed, severe depression, erosions of the mouth, nasal and ocular discharges, dehydration and death. The combination of fever, erosions in the mouth, and diarrhea may closely mimic BVD. The extent and severity of the lesions will vary with the susceptibility of the herd. The time from when the virus is introduced into a susceptible herd and the appearance of clinical signs varies from 3 to 10 days. An entire herd may become infected in less than a month, which is in contrast to most BVD outbreaks in the US where only individual animals are sick at one time. Other diseases somewhat similar to Rinderpest are IBR, Malignant Catarrhal Fever, Bluetongue, salmonellosis and perhaps Johne’s Disease.

There is no treatment for Rinderpest. In most cases, the prognosis for recovery is poor. This is particularly true for areas where it does not occur and the populations of animals are completely susceptible. Under these conditions, the number of animals affected and the death rate may approach 100%. Animals that recover become completely immune.

The US restricts the importation of live animals and unprocessed meats from countries known to have Rinderpest. This is true even for those countries that practice routine vaccination to control this disease. It is one of many foreign animal diseases that are considered reportable in the US. This mean that livestock owners and the veterinarians must report suspected cases of Rinderpest to local regulatory officials. Delays in reporting outbreaks of foreign animal diseases like Rinderpest will permit extensive spread of the disease in the US cattle populations.

In summary, the clinical signs of high fever, erosions of the mouth and GI tract along with severe diarrhea make the foreign animal disease, Rinderpest, a look-a-like disease for BVD that occurs in the US. Because it looks so much like BVD, it perhaps might go undiagnosed unless livestock owners and their veterinarians are on guard for its appearance.

Cow with marked depression due to Rinderpest viral infection.

Severe diarrhea in a cow resulting from Rinderpest infection.

Erosions on the palate of a cow infected with Rinderpest.

Erosions in the intestine of a cow infected with Rinderpest.

Both the morbidity and mortality rates can be expected to be very high in susceptible livestock exposed to Rinderpest.