Assessment of Antiviral Properties of Peramivir against H7N9 Avian Influenza Virus in an Experimental Mouse Model.

The H7N9 influenza virus causes a severe form of disease in humans. Neuraminidase inhibitors, including oral oseltamivir and injectable peramivir, are the first choices of antiviral treatment for such cases; however, the clinical efficacy of these drugs is questionable. Animal experimental models are essential for understanding the viral replication kinetics under the selective pressure of antiviral agents. This study demonstrates the antiviral activity of peramivir in a mouse model of H7N9 avian influenza virus infection. The data show that repeated administration of peramivir at 30 mg/kg of body weight successfully eradicated the virus from the respiratory tract and extrapulmonary tissues during the acute response, prevented clinical signs of the disease, including neuropathy, and eventually protected mice against lethal H7N9 influenza virus infection. Early treatment with peramivir was found to be associated with better disease outcomes.

The "influenza vaccine"--benefit, risk, costs.

More than 20 million people died during the pandemic 'flu season 1918/1919, the largest influenza pandemic of the 20th century. Since then, influenza A virus infections have been known as a serious cause of morbidity and mortality in the whole world population. Although specific and effective antiviral therapeutics (neuraminidase inhibitors) are available, vaccinating against influenza is the first preventative measure. In Germany, influenza immunization has been yearly recommended by the current vaccination committee of the Robert Koch Institute (STIKO). Vaccinations have a special indication in elderly persons >60 years, patients with chronic diseases and persons with higher risk of influenza infections. In general, inactivated vaccines are well tolerated by recipients. The cost effectiveness of influenza vaccination has been well established. Although the benefit of annual influenza vaccination especially for the elderly and risk groups is beyond doubt, a low acceptance of vaccine recommendations has been noticed in Germany to date.

Comparison of intranasal and aerosol infection of mice in assessment of immunity to influenza virus infection.

A comparison was made of intranasal and aerosol routes of infection with X-31 influenza A virus in Balb/c mice. Mice were first infected with 100 MID50 by either route then challenged 42 days later with the same virus given by the same or alternative route. Three days following each infection, pulmonary virus was measured by inoculation of chick embryos. Mice initially infected under ether anesthesia by intranasal inoculation experienced higher initial mortality but proved most resistant to subsequent challenge by either method. In contrast, mice first infected by aerosol were least resistant to intranasal challenge, as indicated by increased rate of infection and pulmonary virus titers, but, like mice previously infected intranasally, were not reinfected by the aerosol route. Thus, intranasal infection appears to be more effective both in inducing and challenging immunity from infection. These results should be considered in the design of experiments utilizing influenza virus infection of mice as a model system.