Virus Causes Arthritis in Mice

Japanese researchers have demonstrated that a human virus called HTLV-1 can cause rheumatoid arthritis in mice. Experts said the discovery provides strong proof that viruses can cause arthritis.

HTLV-1 is a so-called retrovirus, closely related to the AIDS virus, that is capable of inserting its own genetic information into the genes of its host during an infection. It causes leukemia and at least two rare degenerative nerve disorders. The virus is estimated to infect perhaps 1% to 2% of Americans, but is thought to infect at least 20% of the Japanese population.

The researchers, from the University of Tokyo and several other institutions, reported last week in the journal Science that they had used genetic engineering techniques to insert the virus’ genes into two strains of mice. When the mice reached 2 to 3 months of age, they developed chronic arthritis.