Efficacy of oseltamivir phosphate to horses inoculated with equine influenza A virus.

This study tested the effectiveness of oseltamivir phosphate (OP), a medication often used to treat influenza, in horses infected with the equine influenza A virus. The researchers found that OP, given orally, reduced symptoms and the duration of the virus, as well as the frequency of secondary bacterial pneumonia in the horses.

Study Setup

• A total of nine horses were involved in the study. They were divided into three groups: one for control, one for treatment, and one for prophylaxis or preventative treatment.
• The treatment group received 2 mg/kg of body weight of OP, twice a day for five days. This regimen commenced from the time the horses began to show fever symptoms above 38.9 degrees Celsius.
• The prophylaxis group was given the same dosage but once a day for five days, and this was started a day before the horses were inoculated with the virus.

Results from the Treatment and Prophylaxis Groups

• In the treatment group, the periods of virus excretion and fever (pyrexia) were significantly shorter than those of the control group.
• Although the prophylaxis group could not entirely prevent virus excretion and pyrexia, their periods were shorter compared to those of the control group.
• Bacterial count relating to Streptococcus equi subsp. zooepidemicus (common cause of secondary bacterial pneumonia in horses) was significantly lower in both the treatment and prophylaxis groups. This measurement was taken from bronchoalveolar lavage fluids collected seven days after the horses were inoculated with the virus.
• The results indicate that the benefits of orally administering OP to horses affected by equine influenza include reduction in the severity of virus excretion, fever, and resulting secondary bacterial pneumonia.

Implications of the Study

• The research suggests that OP can be a potential treatment or prophylactic strategy against equine influenza in horses, contributing to the reduction of the severity and duration of the virus, as well as the risk of secondary bacterial infections.
• Though promising, more extensive studies need to be conducted to validate these findings and determine the optimal dosages and administration protocols for OP in horses affected by the influenza virus.