Abstract
Paratuberculosis, or Johne’s disease, in cattle is caused by Mycobacterium avium subsp. paratuberculosis, which has recently
been suspected to be transmitted through dust. This longitudinal study on eight commercial M. avium subsp. paratuberculosispositive
dairy farms studied the relationship between the number of cows with M. avium subsp. paratuberculosis antibody-positive
milk and the presence of viable M. avium subsp. paratuberculosis in settled-dust samples, including their temporal relationship.
Milk and dust samples were collected in parallel monthly for 2 years. M. avium subsp. paratuberculosis antibodies in milk
were measured by enzyme-linked immunosorbent assay (ELISA) and used as a proxy for M. avium subsp. paratuberculosis shedding.
Settled-dust samples were collected by using electrostatic dust collectors (EDCs) at six locations in housing for dairy cattle
and young stock. The presence of viable M. avium subsp. paratuberculosis was identified by liquid culture and PCR. The results
showed a positive relationship (odds ratio [OR], 1.2) between the number of cows with ELISA-positive milk and the odds of having
positive EDCs in the same airspace as the adult dairy cattle. Moreover, the total number of lactating cows also showed an OR
slightly above 1. This relationship remained the same for settled-dust samples collected up to 2 months before or after the time
of milk sampling. The results suggest that removal of adult cows with milk positive for M. avium subsp. paratuberculosis-specific
antibody by ELISA might result in a decrease in the presence of viable M. avium subsp. paratuberculosis in dust and therefore
in the environment. However, this decrease is likely delayed by several weeks at least. In addition, the data support the notion
that M. avium subsp. paratuberculosis exposure of young stock is reduced by separate housing.
been suspected to be transmitted through dust. This longitudinal study on eight commercial M. avium subsp. paratuberculosispositive
dairy farms studied the relationship between the number of cows with M. avium subsp. paratuberculosis antibody-positive
milk and the presence of viable M. avium subsp. paratuberculosis in settled-dust samples, including their temporal relationship.
Milk and dust samples were collected in parallel monthly for 2 years. M. avium subsp. paratuberculosis antibodies in milk
were measured by enzyme-linked immunosorbent assay (ELISA) and used as a proxy for M. avium subsp. paratuberculosis shedding.
Settled-dust samples were collected by using electrostatic dust collectors (EDCs) at six locations in housing for dairy cattle
and young stock. The presence of viable M. avium subsp. paratuberculosis was identified by liquid culture and PCR. The results
showed a positive relationship (odds ratio [OR], 1.2) between the number of cows with ELISA-positive milk and the odds of having
positive EDCs in the same airspace as the adult dairy cattle. Moreover, the total number of lactating cows also showed an OR
slightly above 1. This relationship remained the same for settled-dust samples collected up to 2 months before or after the time
of milk sampling. The results suggest that removal of adult cows with milk positive for M. avium subsp. paratuberculosis-specific
antibody by ELISA might result in a decrease in the presence of viable M. avium subsp. paratuberculosis in dust and therefore
in the environment. However, this decrease is likely delayed by several weeks at least. In addition, the data support the notion
that M. avium subsp. paratuberculosis exposure of young stock is reduced by separate housing.
| Original language | English |
|---|---|
| Pages (from-to) | 5458-5464 |
| Number of pages | 8 |
| Journal | Applied and Environmental Microbiology |
| Volume | 79 |
| Issue number | 18 |
| DOIs | |
| Publication status | Published - 2013 |