Peste des Petits Ruminants (PPR)

Peste des petits ruminants (PPR) is a highly contagious viral disease that primarily affects small domestic and wild ruminants such as goats, sheep, antelope, and white-tailed deer. PPR is caused by peste des petits ruminants virus (PPRV), which belongs to the Morbillivirus genus of the Paramyxoviridae family, and is a notifiable animal disease under the OIE regulations. A major threat to animal health, the disease also has socioeconomic implications in areas where small ruminants play a crucial role in agriculture. BioVenic focuses on PPR research and is committed to providing customers with comprehensive technical support.

Etiology and Epidemiology

PPRV is an enveloped, pleomorphic RNA virus with similar physicochemical and immunological properties to the rinderpest virus. PPRV is relatively stable in a neutral pH environment, but sensitive to acid, alcohol, and some detergents. The virus is also sensitive to temperature and can lose infectivity at 50℃ for 30 minutes. It can also be deactivated quickly under the action of ultraviolet rays and sunlight.

Fig.1 Schematic representation of the structure of PPRV virion.^1,2

PPR is distributed globally, with high prevalence in Africa, the Middle East, and Asia. At present, it has been found that there is only one serotype of PPRV. PPR tends to infect animals, and goats are more susceptible than sheep. In terms of mortality, goats are 71.6%, higher than sheep. Buffaloes and pigs can also be infected with PPRV, but do not show clinical symptoms. Currently, there are no reports of human infection with PPRV.

Impact on Society

The impact of PPR on society is significant, particularly in regions where small ruminants are vital for food security and economic stability. PPR outbreaks can lead to substantial economic losses due to reduced productivity, increased mortality rates, and trade restrictions imposed on affected regions. The disease affects the livelihoods of small-scale farmers, exacerbating poverty and hindering sustainable development.

Signs and Symptoms of PPR

Clinical symptoms of PPR vary but typically include fever, respiratory distress, nasal and ocular discharge, diarrhea, and oral lesions.

There is generally an incubation period of 4 to 5 days after herd virus infection. The temperature of the sick sheep is as high as 41℃, which lasts for 3 to 5 days, and then there will be clinical symptoms such as lack of energy and loss of appetite. The mouth and nose of the sick sheep appeared purulent mucus, oral mucosa congestion, slight erosion, and other symptoms. These sheep with more serious lesions will have symptoms such as bloody diarrhea and emaciation in the later stage, and pregnant ewes may abort. In the end, it may even lead to the death of sick sheep.

Fig.2 Characteristic symptoms after sheep are infected with PPRV.^3,4

Transmission Routes

PPRV is highly contagious and is mainly transmitted through the respiratory system. In addition, close-range animals can also spread through aerosols. Healthy animals may also be indirectly infected if they come into contact with drinking water, feed, tools, water tanks, and pens contaminated by sick sheep. However, due to the weak resistance of PPRV to the outside world, the survival time of the virus in the outside world is relatively short, so indirect transmission is not the main way of infection.

Diagnosis of PPR

With many years of diagnostic experience, BioVenic develops various customized PPR diagnostic solutions for its customers. The diagnostic methods involved include virus isolation, immunodiagnosis, and molecular diagnosis. We demonstrate a subset of our diagnostic development capabilities below.

• Immunodiagnostics Development
  
  • Agar Gel Immunodiffusion (AGID) Assay
  • Virus Neutralization Assay
  • ELISA, etc.
• Molecular Diagnostics Development
  
  • PCR is the method of choice for confirmation of PPRV.

PPR in the US

While PPR has not been reported in the United States, the threat of introduction remains a concern due to globalization and international travel. Vigilant surveillance systems and strict quarantine measures are essential to prevent the introduction and spread of PPR into the US livestock population. BioVenic, as a leading company in the veterinary industry, actively contributes to developing and implementing surveillance and biosecurity measures.

Treatment, Control, and Prevention of PPR

Currently, PPR has no effective treatment, although sulfa drugs and antibiotics can treat symptoms and prevent secondary infections in the early stages of the disease.

At present, the prevention and treatment of PPRV mainly depend on the immunization of attenuated live vaccines, and recombinant vaccines are also an important research direction.

In addition, biological measures are also an important part of the prevention and control of PPRV. We recommend the following actions,

• Ensure that sheep are not infected with PPR. Before they can be mixed in groups, they must be isolated for at least one month and observed for disease.
• Improve the biological safety of breeding sites, establish and improve the epidemic prevention system, and strengthen epidemic prevention management.
• Ensure that buildings, equipment, and facilities are cleaned and disinfected properly. A thorough disinfection is required when personnel and transport vehicles enter the site.
• When small ruminants are transferred and grazing, it is necessary to prevent cross-infection of PPRV.

BioVenic has always been on the front line against PPR and invested a lot of energy and research. With a strong team of experts, we develop PPR diagnostics methods, reagents, and kits for our customers. And, in some cases, we also provide vaccine and therapeutic development services to our clients. If you need our help, please contact us immediately.

References

1. Munir, Muhammad, et al. "Serodiagnosis of peste des petits ruminants virus." Serological diagnosis of certain human, animal and plant diseases. IntechOpen, 2012.
2. Image retrieved from Figure 2 "A schematic illustration of the PPR virus structure." Munir, Muhammad, et al., 2012, used under [CC BY 4.0], the image title was changed to "Schematic representation of the structure of PPRV virion."
3. Kinimi, Edson, et al. "Paradigm shift in the diagnosis of peste des petits ruminants: scoping review." Acta Veterinaria Scandinavica 62.1 (2020): 1-14.
4. Image retrieved from Figure 2 "Clinical signs in goats and sheep confirmed with peste des petits ruminants virus infection in a farm located in Tanga, Tanzania." Kinimi, Edson, et al., 2020, used under [CC BY 4.0], the image title was changed to "Characteristic symptoms after sheep are infected with PPRV.