A survey of Mycoplasma agalactiae in dairy sheep farms in Spain

Abstract

Background: Contagious Agalactia (CA) is one of the major animal health problems in small ruminants because of its economic significance. Currently, four Mycoplasma spp. have been associated with this syndrome: M. agalactiae, M. mycoides subsp. capri, M. capricolum subsp. capricolum and M. putrefaciens. Their presence has been evaluated in several studies conducted in CA-endemic countries. However, previous Spanish studies have been focused on caprine CA, and there is a knowledge gap regarding which Mycoplasma species are present in sheep flocks from Spain, which has the second highest number of sheep amongst the 27 European Union member states. Consequently, we investigated the presence and geographic distribution of the four CA-causing mycoplasmas in Spanish dairy sheep farms. This is the first time such an investigation has been performed.

Results: Three hundred thirty nine out of 922 sheep flocks were positive for M. agalactiae by real time PCR (36.8%) and 85 by microbiological identification (9.2%). Interestingly, all 597 milk samples assessed for the presence of M. mycoides subsp. capri, M. capricolum subsp. capricolum and M. putrefaciens tested negative. To evaluate the intermittent excretion of the pathogen in milk, we sampled 391 additional farms from 2 to 5 times, resulting that in 26.3% of the cases a previously positive farm tested negative in a later sampling.

Conclusions: M. agalactiae was the only Mycoplasma species detected in the study area showing a high frequency of presence and wide distribution. Therefore, the establishment of a permanent surveillance network is advantageous, as well as the implementation of control and prevention measures to hinder the dissemination of M. agalactiae and to prevent the entrance of other Mycoplasma species.

Figure 1

Presence of Mycoplasma agalactiae per province over the 2008–2010 period. The color code of each province indicates the presence rate of M. agalactiae. The circles indicate the number of dairy sheep farms sampled once in each province over the sampled period.

Figure 2

Presence of Mycoplasma agalactiae in Spanish sheep farms in 2008, 2009 and 2010. Black bars represent results by real time PCR and grey bars by microbiological identification. The numbers in brackets represent the number of sampled farms. A) Presence per province; B) presence per year.

Figure 3

Distribution of dairy sheep in Spain and number of farms sampled per province. The color code of each province indicates the number of dairy sheep present in that province in 2012 ( http://www.marm.es/). The circles indicate the number of dairy sheep farms sampled in each province over the 2008–2010 period. Overall, 1,313 farms were sampled.