Equine influenza

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Equine Influenza is a highly contagious viral infection affecting the respiratory system of horses. It is caused by strains of the Influenza A virus specific to the equine species, primarily H3N8, and to a lesser extent, H7N7, which is now considered to be nearly extinct. This disease is characterized by a sudden onset of symptoms, including high fever, coughing, nasal discharge, lethargy, and sometimes, secondary bacterial infections. Equine influenza is of significant concern in the equine industry due to its rapid spread and economic impact.

Transmission

Equine influenza is transmitted through the air via droplets produced when infected horses cough or sneeze. The virus can also spread through contaminated equipment, clothing, and hands. Due to its high contagiousness, outbreaks can occur rapidly in populations of unvaccinated horses, emphasizing the importance of vaccination and biosecurity measures.

Symptoms

The primary symptoms of equine influenza include:

• High fever, often exceeding 41°C (105.8°F)
• Dry, hacking cough
• Nasal discharge
• Lethargy and weakness
• Loss of appetite
• Enlarged lymph nodes

Secondary bacterial infections can complicate the disease, leading to more severe respiratory problems such as pneumonia.

Diagnosis

Diagnosis of equine influenza is based on clinical signs, epidemiological information, and laboratory tests. Polymerase chain reaction (PCR) assays and virus isolation from nasal swabs are the most definitive methods for diagnosing this infection.

Treatment

Treatment for equine influenza primarily involves supportive care to relieve symptoms and prevent secondary infections. This includes rest, non-steroidal anti-inflammatory drugs (NSAIDs) to reduce fever and inflammation, and antibiotics if secondary bacterial infections are present. Complete rest is crucial; a general rule is one week of rest for every day of fever.

Prevention

Vaccination is the cornerstone of preventing equine influenza. Various vaccines are available, including inactivated, canarypox vector, and live attenuated vaccines. It is recommended to vaccinate at-risk horses every 6 to 12 months. Biosecurity measures, such as quarantine for new arrivals and isolation of infected horses, are also critical in preventing the spread of the virus.

Economic Impact

Equine influenza can have a significant economic impact on the equine industry, including costs associated with treatment, loss of training and competition days, and the implementation of biosecurity measures during outbreaks.

See Also

• Influenza A virus
• Viral infections in animals
• Respiratory system of the horse
• Vaccination of horses