Researchers have developed the first animal model of the infection caused by chikungunya virus (CHIKV), an emerging arbovirus associated with large-scale epidemics that hit the Indian Ocean, seriously affecting the French Island of La Reunion in 2005, before spreading to India, and Italy in 2007.

Using a mouse model, scientists of the Pasteur Institute and INSERM in France determined which tissues and cells are infected by the virus in both the mild and severe forms of the disease.

They document their findings in an article published in the latest issue of the U.S. online open-access journal PLoS Pathogens.

The main symptoms of CHIKV -- fever, joint and muscle pains, and skin rash -- are now well known by the medical community and the general public. However, the physiological processes related to this infection remain poorly understood, notably the factors responsible for severe disease with neurological manifestations, which are mainly observed among newborns and the elderly.

With the model, the researchers show how after an initial phase of viral replication in the liver, the infection extends to the joints, muscles and skin -- where the symptoms materialize in humans. In the most severe cases, it then disseminates to the central nervous system. The model also allowed the investigators to study the mother-to-child transmission of the virus, a complication that was recorded for the first time during the La Reunion outbreak.

The development of the mouse model provides chikungunya researchers with an experimental tool that sheds light on the physiological processes of the infection, paving the way for future treatments and vaccine candidates against this emerging viral disease, said the journal PLoS Pathogens.

(Agencies via Xinhua News Agency February 21, 2008)