Abstract
BackgroundMany studies have been conducted to define risk factors for the transmission of bovine paratuberculosis, mostly in countries with large herds. Little is known about the epidemiology in infected Swiss herds and risk factors important for transmission in smaller herds. Therefore, the presence of known factors which might favor the spread of paratuberculosis and could be related to the prevalence at animal level of fecal shedding of Mycobacterium avium subsp. paratuberculosis were assessed in 17 infected herds (10 dairy, 7 beef). Additionally, the level of knowledge of herd managers about the disease was assessed. In a case–control study with 4 matched negative control herds per infected herd, the association of potential risk factors with the infection status of the herd was investigated.ResultsExposure of the young stock to feces of older animals was frequently observed in infected and in control herds. The farmers’ knowledge about paratuberculosis was very limited, even in infected herds. An overall prevalence at animal level of fecal shedding of Mycobacterium avium subsp. paratuberculosis of 6.1% was found in infected herds, whereby shedders younger than 2 years of age were found in 46.2% of the herds where the young stock was available for testing. Several factors related to contamination of the heifer area with cows’ feces and the management of the calving area were found to be significantly associated with the within-herd prevalence. Animal purchase was associated with a positive herd infection status (OR = 7.25, p = 0.004).ConclusionsNumerous risk factors favoring the spread of Mycobacterium avium subsp. paratuberculosis from adult animals to the young stock were observed in infected Swiss dairy and beef herds, which may be amenable to improvement in order to control the disease. Important factors were contamination of the heifer and the calving area, which were associated with higher within-herd prevalence of fecal shedding. The awareness of farmers of paratuberculosis was very low, even in infected herds. Animal purchase in a herd was significantly associated with the probability of a herd to be infected and is thus the most important factor for the control of the spread of disease between farms.
Highlights
Many studies have been conducted to define risk factors for the transmission of bovine paratuberculosis, mostly in countries with large herds
The aim of the present study was to acquire further knowledge on Mycobacterium avium ssp. paratuberculosis (MAP) infection in affected Swiss dairy and beef herds, to assess the level of disease awareness of herd managers, to identify risk factors associated with high within-herd prevalence, and to identify risk factors which are more common in infected herds than in herds without a PTB history
The present study allowed for identifying the management parameters in Swiss cattle herds that are significantly associated with the infection status in regard to PTB and with the prevalence of fecal MAP excretion within infected herds
Summary
Many studies have been conducted to define risk factors for the transmission of bovine paratuberculosis, mostly in countries with large herds. Little is known about the epidemiology in infected Swiss herds and risk factors important for transmission in smaller herds. The presence of known factors which might favor the spread of paratuberculosis and could be related to the prevalence at animal level of fecal shedding of Mycobacterium avium subsp. Clinical signs include profuse diarrhea unresponsive to treatment and significant weight loss in spite of good appetite. Once these symptoms are established, the disease is characterized by chronic wasting with a fatal outcome. Clinical signs usually appear only several years after infection, considerably later than the onset of fecal shedding of the germ. The pathogen is primarily transmitted by the fecal-oral route [4], but it may be secreted directly into colostrum and milk [5]; intrauterine transmission has been described [6]
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