Hendra virus (HeV) and Nipah virus (NiV) are recently emerged, closely related and highly pathogenic paramyxoviruses that cause severe disease such as
encephalitis in animals and humans with fatality rates of up to 75 %. Due to their high case fatality rate following human
infection and because of the lack of effective
vaccines or
therapy, they are classified as Biosafety Level 4 pathogens. A recent study reported that
chloroquine, an
anti-malarial drug, was effective in preventing NiV and HeV
infection in cell culture experiments. In the present study, the
antiviral efficacy of
chloroquine was analysed, individually and in combination with
ribavirin, in the treatment of NiV and HeV
infection in in vivo experiments, using a golden hamster model. Although the results confirmed the strong
antiviral activity of both drugs in inhibiting viral spread in vitro, they did not prove to be protective in the in vivo model.
Ribavirin delayed death from
viral disease in NiV-infected hamsters by approximately 5 days, but no significant effect in HeV-infected hamsters was observed.
Chloroquine did not protect hamsters when administered either individually or in combination with
ribavirin, the latter indicating the lack of a favourable
drug-drug interaction.