Disease and cause
Rinderpest is an acute, usually fatal, viral disease principally of cattle. The disease affects the gastrointestinal and respiratory systems. It is a devastating disease of cattle and some wild artiodactyls (African buffalo, giraffe, eland and kudu) with death rates during outbreaks approaching 100%. Rinderpest is caused by a virus belonging to the family Paramyxoviridae.
Cattle and buffalo are highly susceptible and rinderpest is most frequently seen in these species. Sheep and goats may develop clinical signs but serious disease is uncommon. Disease occurs but may be inapparent in camels, deer and pigs. Humans are not affected.
The disease occurs in parts of Africa, the Middle East, Pakistan, India and Nepal. An outbreak in Russia was reported to OIE in 1998. It has been eliminated from China and most of South East Asia. There was an occurrence of rinderpest in Western Australia in 1923 that was quickly eradicated. The disease has never recurred in Australia.
There is sudden onset of fever, followed by depression, loss of appetite, reduced milk production, nasal and eye discharges and laboured, rapid breathing. Irregular erosions appear in the mouth, lining of the nose and genital tract. Acute diarrhoea is a common feature of the disease. Most animals die 6-12 days after onset of clinical signs.
The virus is excreted 1-2 days before clinical signs are observed. Virus is found in expired air, eye and nose discharges, saliva, faeces, urine and milk. Transmission is mainly through aerosols. Infection spreads to new areas by movement of infected animals. Recovered animals have a solid immunity and there is no known chronic carrier state. Indirect transmission by clothing, equipment and so on, is unlikely as the virus does not persist in the environment.
Persistence of the virus
The virus is relatively heat-sensitive, being rapidly inactivated at 56°C, and does not persist in the environment. The virus can be detected in the milk of recovered animals up to 45 days after recovery and occurs in milk 1-2 days before clinical signs develop. The virus is sensitive to a wide range of disinfectants.
The strategy if an outbreak occurs in Australia is eradication by:
§ stamping out to remove the source of infection
§ strict quarantine and movement controls to prevent spread
§ decontamination to eliminate the virus
§ tracing and surveillance to detect the extent of infection
§ zoning to define infected and disease-free areas.
Vaccines are available overseas and may be considered in certain circumstances.