Recovery of Mycobacterium avium subsp paratuberculosis from nematode larvae cultured from the faeces of sheep with Johne's disease

A study was conducted to determine whether trichostrongylid nematode larvae become contaminated with Mycobacterium avium subsp. paratuberculosis when they develop in the faeces of sheep with Johne's disease. Nematode larvae w ere hatched from ova in the faecal samples of affected sheep. Larval sheath s were removed and these as well as exsheathed larvae were subjected to rad iometric culture for M. paratuberculosis. The organism was recovered from w ashing water used to prepare the larvae, third stage larvae and larval shea ths, but not from exsheathed larvae. The recovery of M. paratuberculosis fr om larvae was associated with the severity of the histological lesions in a ffected sheep and with the results of culture of the organism from intestin al tissues and faeces. Nematode parasites of sheep might be able to act as mechanical vectors for M. paratuberculosis as the organism associates with infective third stage larvae when these develop in the faeces of sheep with Johne's disease. (C) 2001 Elsevier Science B.V. All rights reserved.