Rabbit Hemorrhagic Disease (RHD) is a highly contagious and often fatal illness that can rapidly kill rabbits, making it a primary concern for rabbit owners and wildlife conservationists alike.
Understanding Rabbit Hemorrhagic Disease (RHD)
Rabbit Hemorrhagic Disease (RHD) is a severe viral disease that affects both domestic and wild rabbit species, including European rabbits and hares. Caused by a calicivirus, RHD is notorious for its rapid progression and extremely high mortality rate, often leading to sudden death with few or no observable symptoms. This disease is nearly always fatal and primarily affects adult rabbits, though newer strains can affect younger animals as well.
Key Characteristics of RHD
RHD is characterized by its quick onset and devastating impact. Understanding its core features is crucial for appreciating its danger.
| Feature | Description |
|---|---|
| Causative Agent | Calicivirus (e.g., RHDV1, RHDV2/RHDVb) |
| Contagiousness | Highly contagious, spreading quickly among rabbits |
| Fatality Rate | Nearly always fatal (up to 90-100% in susceptible populations) |
| Affected Animals | Domestic and wild rabbits, primarily adults |
| Disease Progression | Often rapid, leading to sudden death within 12-36 hours of symptom onset |
How RHD Spreads
RHD is extremely contagious and can spread through various means, making biosecurity a critical aspect of prevention.
- Direct Contact: Contact with infected rabbits, whether live or deceased.
- Indirect Contact (Fomites): The virus can survive on contaminated objects such as:
- Food and water bowls
- Bedding and litter
- Clothing and shoes
- Equipment, cages, and transport vehicles
- Vectors: Insects (like flies), birds, rodents, and even predators can act as mechanical vectors, carrying the virus from one location to another.
- Environmental Persistence: The virus is robust and can persist in the environment for extended periods, especially in cool, moist conditions.
Recognizing the Signs
One of the most concerning aspects of RHD is that infected rabbits often die suddenly without any prior clinical signs. However, if symptoms are observed, they can include:
- Sudden Death: This is the most common presentation, often with no preceding illness.
- Lethargy and Loss of Appetite: Rabbits may become unusually quiet and refuse to eat.
- Fever: An elevated body temperature can be a sign.
- Respiratory Distress: Difficulty breathing, nasal discharge, or frothy discharge from the nose.
- Neurological Signs: Tremors, seizures, incoordination.
- Bleeding: In some cases, internal hemorrhaging can lead to bloody discharge from orifices (nose, mouth, rectum).
Protecting Rabbits from RHD
Prevention is the most effective strategy against RHD due to its high fatality rate. Key measures include:
- Vaccination: Effective vaccines are available and highly recommended for all domestic rabbits, especially in areas where RHD is prevalent. Consult your veterinarian for the appropriate vaccination schedule.
- Strict Biosecurity: Implement rigorous hygiene practices:
- Wash hands thoroughly before and after handling rabbits.
- Disinfect cages, food bowls, and equipment regularly.
- Avoid sharing equipment with other rabbit owners.
- Control insect populations around rabbit enclosures.
- Quarantine new rabbits for at least 30 days before introducing them to existing rabbit populations.
- Environmental Control: Be mindful of where your rabbits graze or where their food/hay comes from, as wild rabbits can be carriers.
- Limit Exposure: Restrict contact with wild rabbits or areas where wild rabbits are known to live.
Why RHD is So Dangerous
RHD's danger lies in its rapid onset, high fatality rate, and ease of transmission. The virus quickly attacks internal organs, leading to hemorrhage and organ failure. For rabbit populations, a single outbreak can be devastating, wiping out entire colonies in a short period. Early detection is often impossible due to the lack of visible symptoms before death, making preventative measures the cornerstone of protection.
For more detailed information on Rabbit Hemorrhagic Disease, you can refer to resources from animal health organizations such as the USDA Animal and Plant Health Inspection Service (APHIS).
