Mice as paratenic hosts of Aelurostrongylus abstrusus

Background: Several species of nematodes included in the superfamily Metastrongyloidea are recognized agents of parasitic infections in felines. Aelurostrongylus abstrusus is the most prevalent species affecting the respiratory system of domestic cats. The route of infection in cats is supposed to be through ingestion of gastropod intermediate or paratenic hosts. However, because gastropods are not the preferred preys of cats, rodents were suggested to play an important role as paratenic hosts in the biological cycle of A. abstrusus and in the epidemiology of aelurostrongylosis. Results: Two studies were conducted to document histopathological tissue lesions in mice experimentally infected with A. abstrusus third-stage larvae (L3) (Study 1), and to determine larval counts in their organs (Study 2). Additionally, cats were fed with experimentally infected mice to assess their infectivity. Aelurostrongylus abstrusus L3 were recovered from the liver, spleen, brain, skeletal muscle and gastrointestinal tract tissues by artificial digestion, and heart, spleen and brain tested positive for A. abstrusus at molecular diagnosis. Multifocal encephalitis and meningitis and glial nodules were the most common histopathological lesions found in mice inoculated with A. abstrusus. All cats shed first-stage larvae of A. abstrusus after ingestion of mice inoculated with this nematode. Conclusions: In this study, we provide information on the anatomical localization, histopathological alterations and rate of recovery of A. abstrusus L3 in mice, and confirm their infectivity to cats (definitive hosts) after feeding on infected mice (paratenic hosts). Data presented here add knowledge to further understand the biology of A. abstrusus in mice and underline the importance of mice as paratenic hosts of this nematode for the infection of cats.