Epidemiology of Pig Tuberculosis in Argentina

Abstract

Bovine tuberculosis (bTB) is a disease caused mainly by the Mycobacterium bovis and that is endemic to livestock populations in most Latin American countries. Traditionally, bTB control programs are costly and targeted to cattle, largely disregarding other species such as swine and wildlife. According to official services, in Argentina disease prevalence in pigs is comparable to that observed in cattle, suggesting the need for efficient control programs to manage the disease in both species. Additionally, extensive farming systems, which are commonly practiced in Argentina, allow the interaction between livestock and wildlife such as wild boar (Sus scrofa), which is considered a natural host of the disease. Here, we evaluated the bTB pigs- cattle interface, studying the dynamics of M. bovis isolates in the pig population and identifying farm-level epidemiological variables associated with the disease confirmation at slaughterhouses. Additionally, to assess the potential multi-host systems in the transmission of bTB, the molecular characterization of wild boar mycobacterial strains was included in the study, as this interaction has not been previously evaluated in this region. Multivariable logistic regression models were used to assess the association between farm-level epidemiological variables (location, farm size, and co-existence with cattle and goats) and bTB confirmation in pig tuberculosis-like lesions samples. Results showed that when cattle were present, the odds of bTB in pigs decreased 0.3 or 0.6% for every additional sow when cattle were present or absent in the farm, respectively. Pigs shared 60% (18/30) of the genotypes with cattle and wild boar, suggesting transmission at the interface between pigs and cattle and highlighting the potential role of wild boar in bTB maintenance. These results provide novel information about the molecular diversity of M. bovis strains in pigs in Argentina and proposes the potential relevance of a multi-host system in the epidemiology of bTB in the region. The statistical models presented here may be used in the design of a low cost, abattoir-based surveillance program for bTB in the pig industry in Argentina, with potential extension to other settings with similar epidemiological conditions.

Detection of non-tuberculous mycobacteria in native wildlife species at conservation risk of Argentina

“…The presence of NTM in free-ranging animals that share their environment with livestock highlights the need to differentiate mycobacteria species, because of the potential interference in diagnostic tests, to control mTB ( 4 , 68 , 70 ). In Argentina, there is a particular scenario where extensive livestock farming is the most frequent strategy, allowing domestic and wild animals to interact in the same environment, increasing the likelihood of disease transmission between them, compared to more confined and intensive farming scenarios ( 56 , 69 ). The adverse consequences associated with the introduction of livestock into habitats occupied by native fauna have been extensively documented, primarily due to the spread of infectious and parasitic diseases ( 71 – 78 ).…”

“…These Mycobacteria can be isolated from soil, water and occasionally have been associated with disease in animals and humans (3,(49)(50)(51)(52)(53)(54)(55). M. avium has been isolated from several wild species (4) and MAH has already been reported in wild and domestic animals in Argentina (56). M.intrcellulare has been reported causing disease in a capybara subjected to stressful conditions and causing lesions similar to other pathogenic Mycobacteria (5).…”

Cattle tuberculosis, farm management, and host species richness in a high prevalence area of Western Spain

“…We found particularly relevant results regarding cattle contact with wild MTC susceptible hosts and MTC host species richness. Sheep are part of the MTC maintenance communities in speci c circumstances (Muñoz-Mendoza et al 2016;Pozo et al 2024); and, in some regions, TB prevalence in pigs is comparable to the one observed in cattle(Barandiaran et al 2021). However, we found an absence of evidence of a statistically signi cant effect of the numbers of both species, when considered on their own, with respect to TB-status.…”