Porcine Rotavirus Disease

Porcine rotavirus disease has emerged as a significant contributor to elevated piglet mortality since its identification, inflicting substantial economic losses upon the breeding sector. As the scale of breeding operations expands, the landscape of prevention measures for porcine rotavirus disease grows increasingly intricate.

Etiology

Rotaviruses belong to the Reoviridae family, encompassing the Rotavirus genus. These viruses are grouped into various serogroups, denoted by letters A, B, C, E, and H, all capable of affecting swine. Predominantly, group A strains are the most prevalent and extensively researched. Group B strains are less comprehensively understood and often coexist with other serogroups. Group C strains are commonly identified in contaminated settings. Group E strains are rarely documented, whereas group H strains are emerging pathogens recognized in both porcine and human populations.

Fig. 1 Schematic representation of the structure of Rotaviruses.¹

Transmission

The primary mode of transmission for this virus is through the fecal-oral route. Infected pigs shed the virus in their feces, which subsequently contaminates the environment. The virus can persist in the environment for extended periods, facilitating widespread infection. Pigs of all age groups are susceptible to rotavirus infection.

Fig. 2 The replication cycle of porcine rotavirus.²

Cause and Effect

Rotaviruses showcase notable environmental robustness, allowing them to persist for prolonged periods, thereby posing a continuous hazard to piglets.

Upon infection of a piglet with rotavirus, the virus undergoes replication within mature enterocytes. These enterocytes, specialized cells lining the small intestine responsible for nutrient absorption, become the epicenter of viral activity. As the infection advances, the proliferating virus takes a toll on these cells, resulting in their destruction. This, in turn, triggers the atrophy of villi-finger-like structures crucial for nutrient absorption. The resulting disturbance in regular intestinal functioning impedes nutrient assimilation, concurrently fostering an osmotic effect. This compounded effect worsens diarrhea and dehydration in afflicted pigs.

Signs and Symptoms

Porcine rotavirus disease primarily manifests as diarrhea in affected pigs. The severity and age of incidence differ based on the rotavirus group and management conditions.

• Sows
  
  • Short-term diarrhea.
  • May exhibit or lack evident clinical manifestations.
• Piglets
  
  • Watery and profuse diarrhea.
  • Villus atrophy results in dehydration, malabsorption, and wastage.
  • Diarrhea persists for 3-4 days.

  • Abdominal hollowness and dehydration.
  • Sunken eyes.
  • Wet skin around the rectum.
• Weaners and Growers
  
  • Watery diarrhea.
  • Severity decreases with age.
  • Villus atrophy resulting in malabsorption.
  • Diarrhea lasts 3-4 days.

  • Abdominal hollowness.
  • Dehydration.
  • Sunken eyes.

Diagnosis

When a pig farm experiences instances of diarrhea affecting pigs aged 10-40 days, it's prudent to consider the possibility of rotavirus infection as a potential root cause. As a skilled diagnostic CRO, BioVenic regularly utilizes multiple laboratory methods to develop precise diagnostic solutions for clients, covering the following diagnostics technologies.

• Virus Neutralization Assay
• Fluorescence in Situ Hybridization (FISH)
• Immunohistochemistry (IHC) Assay
• ELISA
• RT-PCR, etc.

Treatment

Indeed, there is no specific treatment protocol available for rotaviral infections in piglets. However, a holistic approach combining supportive measures, effective management practices, and stringent biosecurity protocols can aid in the management of rotavirus-affected piglets.

Supportive interventions may involve offering electrolytes in drinking water to address dehydration and providing suitable nutrition tailored to the piglets' age and needs. It's important to note that antibiotics do not target rotaviruses directly. Nevertheless, they could be utilized to address secondary bacterial infections if they are present alongside the viral infection.

Prevention and Control

Preventing and controlling porcine rotavirus disease requires a multifaceted approach. BioVenic formulates preventive measures for customers according to the actual situation of the farm.

• Biosecurity and Management Practices
  
  • Adopt an all-in all-out management system to enhance disease control.
  • Conduct meticulous cleaning and disinfection of the breeding environment and equipment.
  • Consider shortening the farrowing period to reduce the potential buildup of rotaviruses.
• Vaccination
  
  • BioVenic specializes in the development of modified rotavirus attenuated live vaccines and inactivated rotavirus vaccines tailored to clients' needs.
  • Administering vaccines to the mother before farrowing can confer passive immunity to the piglets.
• Optimizing Nutrition and Gut Health
  
  • Furnish sows and gilts with a premium diet to optimize colostrum and milk production.
  • Offer piglets colostrum promptly after birth to bolster passive immunity.
  • Incorporate probiotics and prebiotics to cultivate advantageous gut microflora and enhance gut well-being.

BioVenic works with other organizations to continue to improve the understanding of porcine rotavirus disease. Continued research to improve vaccines and antiviral therapies to minimize their impact on pig health and welfare. If you want to become our partner, please contact us immediately.

References

1. Trask, Shane D, et al. "Structural insights into the coupling of virion assembly and rotavirus replication." Nature reviews microbiology 10.3 (2012): 165-177.
2. Kumar, Deepak, et al. "Rotavirus infection in swine: genotypic diversity, immune responses, and role of gut microbiome in rotavirus immunity." Pathogens 11.10 (2022): 1078.