Global eradication of peste des petits ruminants

Alison Lee, Agriculture Victoria, Warrnambool

The detection of both Foot-and-mouth disease (FMD) and Lumpy skin disease (LSD) in Indonesia last year served as a reminder of the ever-present risk of an emergency animal disease (EAD) incursion within Australia. Clearly, EADs impact our export markets, affect animal health, welfare and productivity, and the cost of responding to an incursion is usually substantial.

Wouldn’t it be tremendous if we could globally eradicate EADs so they no longer posed a risk to Australia, like we did with smallpox in humans? Well, the good news is this has been done previously in the livestock industries.

In June 2011, the cattle disease, rinderpest was officially recognised as eradicated from the globe. Rinderpest was a highly contagious disease of cattle and buffalo, with death rates often as high as 100 per cent. Eradication was achieved through hard work, dedication and perseverance in many countries, and Australia is a beneficiary of this accomplishment.

You may be aware that a closely related disease to rinderpest occurs in sheep and goats. This disease is called peste des petits ruminants (PPR), sometimes also referred to as sheep and goat plague. Unlike rinderpest, it hasn’t yet been eradicated.

Since first being reported in western Africa about 70 years ago, PPR has spread widely around the globe. PPR hasn’t been reported in Australia to date, but it has spread exponentially in recent years, and is now present in over 70 countries throughout Asia, Africa, the Middle East. It reached Europe as recently as 2016. This disease has a considerable impact on rural economies and the livelihoods of farmers where present.

Although the risk of an incursion of PPR in Australia is considered lower than some of the more commonly referred to EADs, such as FMD, it would be naïve to consider ourselves ‘safe’ from an incursion. An outbreak of PPR in Australia would result in significant animal welfare issues and enormous economic losses within the Australian sheep and goat industries, processing sectors and the general community.

Goats tend to be more severely affected than sheep, with signs ranging from high fever, conjunctivitis, respiratory disease, severe diarrhoea, abortions, and death. Clinical signs in sheep have been reported to be similar but generally less severe than goats.

As the Australian sheep and goat population is naïve to PPR, clinical signs in both species may be equally severe.
PPR virus doesn’t survive long outside its host, therefore spread is usually via the movement of infected sheep or goats. Australia’s strict biosecurity requirements reduce the likelihood that PPR would enter via live animals. The illegal importation of semen and embryos is likely to pose the highest risk for an incursion.

The good news for the sheep and goat industries is following the successful eradication of rinderpest, efforts are now being directed towards the global eradication of PPR. Developed in 2015, the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (WOAH) oversee the PPR Global Eradication Program.

The program relies heavily on disease surveillance and the large-scale vaccination of sheep and goats. Despite the widespread global distribution of PPR, the program is committed to eradicating PPR globally by 2030. Recent events, such as the COVID-19 pandemic, have hindered progress due to logistical issues and increased costs associated with the transportation and delivery of PPR vaccine. However, the program continues with the aim that PPR may be another disease of only historical significance within the next decade.

You can learn more about the eradication of PPR by reviewing the Global Strategy for the Control and Eradication of PPR report on the World Organisation for Animal Health website.

If you suspect PPR (or any other EAD) in your flock, please call your local Agriculture Victoria veterinarian or the Emergency Animal Disease Watch Hotline (1800 675 888) immediately. We would much rather exclude many EADs in suspected cases than miss the one important confirmed positive case!