Abstract: Objective To investigate the pathogenicity of Alternaria alternata in ICR mice.Methods The cell suspension of Alternaria alternata was inoculated into testes and footpads of normal and immunocompromised ICR mice.Histopathologic examination and fungal culture were performed on 5th d, 7th d, 10 th d, 14th d, 21st d, 28th d, 35th d and 42nd d respectively after inoculation.Results The abscesses were developed at the inoculated sites in all normal and immunocompromised mice.The lesions in immunocompromised mice were more severe and persisted longer than those in normal mice.The abscesses in footpads mostly disappeared within 14 days in normal mice but in 28 to 35 days in immunocompro mised mice.Alternaria alternata was isolated from the inoculated tissues in both groups.The histopathologic examination showed abscess and granulomas in which thick hyphae were observed.The necropsy revealed no disseminated infection of Alternaria alternate in all the test mice.Conclusion Alternaria alternata is a kind of opportunistic fungus with low virulence.

Key words: Alternaria, Mycoses, Animal testing alternatives