Bovine Parainfluenza Type 3 Virus Infection

Bovine parainfluenza type 3 virus (BPIV-3) infection is a well-recognized viral respiratory disease affecting cattle populations worldwide. Leveraging extensive industry expertise, BioVenic specializes in assisting customers in the development of diagnostics solutions for BPIV-3 infections, along with the creation of vaccines aimed at preventing or treating this prevalent viral respiratory disease in cattle herds worldwide.

Etiology

BPIV-3 is a single-stranded, non-segmented RNA virus belonging to the Paramyxoviridae family and the Respirovirus genus. BPIV-3 has a genome of about 15,000 nucleotides and encodes six kinds of proteins, including a nucleoprotein encoded by the NP gene.

Infections due to BPIV-3 are prevalent in cattle, particularly affecting young calves with poor passive transfer or decayed maternal antibodies. While BPIV-3 is capable of causing clinical disease, it is typically associated with mild or subclinical infections. However, its critical role lies in acting as a trigger for the development of secondary bacterial pneumonia, which can significantly exacerbate the condition.

Fig.1 Structural diagram of BRSV and BPIV-3.^1,2

Distribution

BPIV-3 is an acute contagious respiratory infectious disease of cattle. Since BPIV-3 was first isolated from cattle in 1959, it has been widely used in countries all over the world, such as America, Europe, and many countries in Asia where cattle are intensively raised.

Sustainable Animals

BPIV3 can infect a variety of animals, including pigs, cattle, primates, and various experimental animals, but cattle are the most susceptible animals.

Transmission

The most important source of infection of BPIV-3 is sick cattle and infected cattle, especially some subclinically infected cattle are the most dangerous source of infection, which can often aggravate the prevalence of the disease.

BPIV-3 can be transmitted through direct contact with the secretions of infected animals, such as nasal secretions, eye secretions, etc., and can also be transmitted through the respiratory tract through droplets. There are also reports of virus isolation from bull semen and cow reproductive tract, so BPIV-3 also has the possibility of vertical transmission.

Pathogenesis

The way BPIV-3 infection develops is through the virus attaching and entering the respiratory epithelial cells of animals that are susceptible to it. The virus then replicates in the respiratory tract, leading to damage in the form of pulmonary consolidation, bronchitis, bronchiolitis, and alveolitis. Severe cases are often accompanied by secondary bacterial bronchopneumonia, which can cause significant morbidity and mortality in affected animals.

Signs and Symptoms

Clinical signs of BPIV-3 infection primarily manifest as respiratory symptoms. Infected cattle may display fever, cough, serous nasal discharge, lacrimal fluid, increased respiratory rate, and abnormal lung sounds. In cases where the disease is not complicated by bacterial pneumonia, the clinical signs are usually mild, and mortality is uncommon.

Diagnosis

Due to its high susceptibility to co-infection with other pathogens, the symptoms exhibited by sick cattle infected with BPIV-3 can be complex. Therefore, laboratory testing is necessary to confirm the diagnosis.

• Pathogenic Detection
  
  • Virus Isolation and Identification: The method is to collect nasal swabs or diseased tissues from sick cattle and inoculate bovine kidney passage cells (MDBK) after treatment for culture.
• Molecular Diagnostics
  
  • RT-PCR: We design primers based on the conserved region of the BPIV-3 HN gene to help develop RT-PCR detection kits.
  • RT-LAMP: We design 4 primers based on the BPIV3 NP gene to develop RT-LAMP kits for customers.
  • Fluorescent quantitative RT-PCR: We design primers and probes based on the BPIV-3 M gene and develop RT-PCR detection kits for customers.
• Immunodiagnostics
  
  • Immunofluorescence Assay (IFA)
  • Virus Neutralization Assay
  • ELISA
  • Hemagglutination Inhibition (HI) Test
  • Hemagglutination Test (HA): BPIV-3 can agglutinate chicken and guinea pig cells, and BPIV-3 can be identified based on this property.

Treatment

Treatment for BPIV-3 infection is primarily focused on managing clinical signs. Non-steroidal anti-inflammatory drugs (NSAIDs) therapy helps alleviate fever and discomfort in affected animals. Additionally, secondary bacterial pneumonia may require antibiotic treatment to address bacterial co-infections.

Prevention and Control

As a leading company in animal disease diagnostics, BioVenic advocates a comprehensive approach to combat BPIV-3 infection. This includes the following measures,

• Minimize the introduction of cattle, and adhere to the self-breeding and self-raising policy of the farm.
• It is important to also focus on improving the breeding environment and sanitation management of the farm. Regularly cleaning and disinfecting animal waste is crucial in maintaining a healthy and safe environment.
• Long-distance stress and climate change increase the probability of BPIV-3 infection, so minimizing this stress can reduce infection and disease in cattle.
• Sick cattle should be isolated in time, and the utensils and personnel in the feeding environment should be fully disinfected.
• Severely ill cattle should be treated with antibiotics or a combination of antibiotics and antiviral drugs in time.
• Vaccination with inactivated and attenuated BPIV-3 vaccines, usually multiple vaccines against several pathogens.

In summary, BPIV-3 infection poses a major challenge to cattle herds worldwide. At BioVenic, our focus is on safeguarding cattle health by developing diagnostics solutions and more effective vaccines for veterinarians and animal health researchers. If you need our technical support, please feel free to contact us.

References

1. Makoschey, Birgit, et al. "Review on bovine respiratory syncytial virus and bovine parainfluenza–usual suspects in bovine respiratory disease–a narrative review." BMC veterinary research 17.1 (2021): 1-18.
2. Image retrieved from Figure 1 "Morphology of BRSV and BPIV3." Makoschey, Birgit, et al., 2021, used under [CC BY 4.0], the image title was changed to "Structural diagram of BRSV and BPIV-3."