Distribution of Brucella field strains isolated from livestock, wildlife populations, and humans in Italy from 2007 to 2015.
Authors: De Massis Fabrizio, Zilli Katiuscia, Di Donato Guido, Nuvoloni Roberta, Pelini Sandro, Sacchini Lorena, D'Alterio Nicola, Di Giannatale Elisabetta
Journal: PloS one
Summary
# Editorial Summary: Brucella Epidemiology in Italy Between 2007 and 2015, the Italian National Reference Laboratory for Brucellosis characterised 5,784 field strains using classical and molecular typing techniques, revealing distinct epidemiological patterns across livestock, wildlife, and human populations. *Brucella abortus* dominated in cattle (90.1% of bovine isolates) and water buffalo (95.9%), whilst *B. melitensis* biovar 3 was overwhelmingly prevalent in sheep and goats (95.3%), and *B. suis* biovar 2 emerged as the primary strain in wild boar (98.3%) and domestic pigs. Notably, the two equine isolates were typed as *B. abortus* biovar 1, suggesting horses may serve as incidental hosts in endemic regions, whilst human infections were exclusively *B. melitensis* biovar 3, reflecting exposure pathways through small ruminant products and contact. This comprehensive molecular epidemiological survey highlights how host-pathogen associations shape brucellosis distribution across Italy, with important implications for targeted control strategies: practitioners managing horses in endemic areas should recognise the zoonotic risk, particularly in mixed farming systems with cattle exposure, whilst the wildlife reservoir in wild boar underscores the need for biosecurity measures to prevent spillback into domestic herds. These data support risk-stratified surveillance and vaccination protocols tailored to regional strain prevalence rather than blanket approaches.
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Practical Takeaways
- •Horses are susceptible to brucellosis and can carry B. abortus biovar 1; equine practitioners should maintain awareness of zoonotic transmission risk and implement biosecurity measures when handling infected animals
- •Brucellosis distribution varies by livestock species and geography in endemic regions; understanding local strain prevalence helps inform vaccination and testing protocols in equine operations sharing facilities with other livestock
- •Horses in contact with affected cattle, water buffalo, or wildlife (particularly wild boar) in endemic areas may be at increased infection risk and warrant baseline serological screening
Key Findings
- •Among 5,784 Brucella strains typed from 2007-2015 in Italy, B. abortus represented 53.4% and B. melitensis 43.2% of isolates
- •Cattle predominantly carried B. abortus biovars 1, 3, and 6 (90.1%), while sheep and goats were primarily infected with B. melitensis biovars 1 and 3 (95.3%)
- •Two equine strains were identified as B. abortus biovar 1, representing a minor reservoir species for brucellosis
- •Wild boar served as a significant wildlife reservoir, with 98.3% of isolates typed as B. suis biovar 2