Bats carry SARS like virus

An international consortium headed by CAS researchers has identified that the Chinese horseshoe bat is healthy carriers of a virus that is very closely related to those causing SARS (severe acute respiratory syndrome).

The findings support an independent study with similar results by Hong Kong scientists, which is reported by Sept. 27 issue of Proceedings of the National Academy of Sciences.

The outbreak of the deadly SARS epidemics in 2002 and 2003 infected more than 8,000 people in 26 countries across the world, causing 774 deaths. Earlier studies on the epidemics showed that masked palm civets could be a natural host for the virus.

Prof. Shi Zhengli from the CAS Wuhan Institute of Virology (WHIOV), Prof. Zhang Shuyi from the CAS Institute of Zoology and their colleagues noticed in the research that bats have proved to be a natural host for viruses of some major animal-borne infection diseases, which could be infective to both humans and animals.

Started from March 2004, the research team has collected samples of the blood serum, throat and faecal swabs from 408 bat individuals in four regions across China, which falls into nine species in six genera in three families. Examinations at both labs of IOV in Wuhan and Australian Animal Health Laboratory (AAHL) demonstrated that four species in the Horseshoe Bat (Rhinolophus) genus have SARS virus antibody and genes. One of the species, Great-eared Horseshoe Bat (Rhinolophus macrotis) showed more than 70% positive rate of antibody against the SARS virus. Sequencing analyses indicate that the homology between SARS-like virus and human ones reaches 92%.

However, scientists are quick to point out that the difference between the two is critical for the cross-species spreading of the virus. That is to say, the SARS-like virus in bats may not be contagious to humans.

Zoologists argue that insectivore bats including horseshoe bat are natural enemies for many pests in agriculture and forests, and play an important role in keeping the ecological system balance. It is normal and the result of the evolution for wild animals, such as bats, to carrying various viruses. It is not wise to kill bats in large number because of the discovery. Bats decrease may cause increase of mosquitoes, for instance, that could lead to the outbreak of such infectious diseases as dengue fever. During their studies, scientists strictly abide by the international animal protection rules and do their best to reduce harm to the bats. After obtaining fecal and blood samples, the scientists released the bats into the wild or returned them to their original habitats.