Transmissibility of Mycobacterium pinnipedii in a murine model

The causative agent of tuberculosis in pinnipeds is Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex (MTC). The natural hosts are pinnipeds; however, other non-marine mammals, including humans, can also be infected. The transmissibility of a pathogen is related to its virulence. The transmissibility of a M. pinnipedii strain (i.e., 1856) was investigated in a murine model and compared with that of two Mycobacterium bovis strains (i.e., 534 and 04-303) with different reported virulence. Non-inoculated mice (sentinels) were co-housed with intratracheally inoculated mice. Detailed inspection of mice to search for visible tuberculosis lesions in the lungs and spleen was performed, and bacillus viability at 30, 60, and 90 days post-inoculation (dpi) was assayed. A transmissibility of 100% was recorded at 30 dpi in sentinel mice co-housed with the inoculated mice from the M. pinnipedii and M. bovis 04-303 groups, as evidenced by the recovery of viable M. pinnipedii and M. bovis from the lungs of sentinel mice. Mice inoculated with M. pinnipedii (1856) and M. bovis (534) survived until euthanized, whereas five of the M. bovis 04-303-inoculated mice died at 17 dpi. This study constitutes the first report of the transmissibility of a M. pinnipedii strain in mice and confirms the utility of this experimental model to study virulence features such as the transmission of poorly characterized MTC species.

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

Introduction

Non-tuberculous Mycobacteria (NTM) are mainly environmental but can cause opportunistic infections and diseases in humans and animals. Livestock and wild animals can be infected with NTM. In Argentina, there are native wild species facing conservation risks, and they are the focus of protection and reintroduction projects designed to preserve biodiversity in various ecoregions. The aim of this study was to report the presence of NTM in samples collected from four endangered native wild species from nine Argentine provinces, as part of their pre-release health assessment.

Methods

A total of 165 samples from giant anteater, peccary, tapir and pampas deer were obtained, these included either bronchoalveolar or endotracheal lavages, or oropharyngeal, nasopharyngeal or tracheal swabs. Bacteriological culture followed by molecular identification and sequencing were performed.

Results

A total of 27 NTM were detected, including Mycobacterium avium subsp. hominissuis, M. intracellulare, M. terrae, M. gordonense, M. kumamotonense, M. fortuitum, M. saskatchewanense, and M. genavense. Results revealed a 16,36% NTM recovery rate, with the giant anteater showing the highest prevalence among the mammals under study.

Discussion

In Argentina, due to extensive production systems, the interaction between domestic and wild species sharing the same environment is frequent, increasing the exposure of all the species to these NTM. In this way, the transmission of infectious agents from one to another is feasible. Moreover, NTMs might interfere with the diagnosis of bovine tuberculosis and paratuberculosis. These findings emphasize the importance of active health surveillance in conservation programs. It highlights the need to address NTM epidemiology in wildlife and its impact on conservation and public health.

Molecular detection of Mycobacterium tuberculosis complex in a captive aguará popé (Procyon cancrivorus) with macroscopic tuberculosis like-lesions

Tuberculosis is a chronic and contagious infectious disease caused by multi-host species of the genus Mycobacterium grouped within the Mycobacterium tuberculosis complex. These pathogenic bacteria mainly affect mammals, including humans. The most recognized species is Mycobacterium bovis, the causative agent of bovine tuberculosis in livestock. Although livestock is the main host of M. bovis, this species is frequently isolated from wild animals. Wild native mammals from Central and South America, as the crab-eating raccoon or "aguará popé" (Procyon cancrivorus), may act as a source of tuberculosis and may represent a human health risk, especially in captive scenarios, due to closer animal-human interaction. However, the only presence of infection in wild animals is not enough to determine their epidemiological role in the disease. Here we identify tuberculosis in a captive aguará popé with clinical signs and lung macroscopic tuberculosis-like lesions during necropsy. We detected tuberculosis by polymerase chain reaction assay. DNA was extracted directly from lung tissue and the amplification target was the insertion sequence 6110. This study contributes to investigate the presence of the disease in wild native animals of Argentina and supports the knowledge that wild mammals may act as a source of TB for humans and domestic animals.

Mycobacterium avium in miniature schnauzer from Argentina: a series of cases

Environmental mycobacteria such as those from the Mycobacterium avium-intacellulare complex may cause disseminated and severe disease in dogs with genetic predisposition. A series of cases of four miniature schnauzers with nonspecific clinical signs and the diagnostic tests are described. Complementary means of diagnosis including complete blood count, biochemical serum analyses and fine needle aspiration cytology staining were performed. The bacteriological culture followed by PCR amplification of 1245 and 901 insertion sequences, allowed the identification of Mycobacterium avium subsp. hominissuis. This environmental Mycobacteria normally do not cause severe disease in dogs or other species, but when CARD-9 gene presents mutations, dogs may become extremely susceptible and disease is fast, disseminated and fatal. Antibiotic therapy can be applied under veterinary consideration in specific situations, as treatment is usually applied for a long period of time. Although zoonotic risk is low as the Mycobacterium is environmental, contamination of the location may be high, and immunosuppressed animals and humans can develop infection as well. This report may aid clinical veterinarians in the diagnosis, treatment, and prognosis in similar cases of this breed and others with the genetic predisposition.

Serological survey suggests circulation of coronavirus on wild Suina from Argentina, 2014-2017

Swine coronaviruses affecting pigs have been studied sporadically in wildlife. In Argentina, epidemiological surveillance of TGEV/PRCV is conducted only in domestic pigs. The aim was to assess the prevalence of TGEV/PRCV in wild Suina. Antibodies against these diseases in wild boar and captive collared peccary were surveyed by ELISA. Antibodies against TGEV were found in three collared peccaries (n = 87). No TGEV/PRCV antibodies were detected in wild boar (n = 160). Preventive measures should be conducted in contact nodes where the transmission of agents may increase. Epidemiological surveillance in wildlife populations and in captive animals before their reintroduction should be attempted.

Epidemiology of Pig Tuberculosis in Argentina

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.

Isolation of Nontuberculous Mycobacteria from Bovine Raw Lungs Bought in Butchers' Shops

Nontuberculous Mycobacteria (NTM) can cause opportunistic disease in animals and humans, causing mycobacteriosis. In this study, bovine lungs were collected from butchers' shops and slaughterhouses after food official's inspection from the metropolitan area of Buenos Aires. All samples were cultured and then identified by molecular methods. Twelve isolates of NTM were identified being the most prevalent Mycolicibacterium insubricum. This demonstrates that viable Mycobacteria can pass food inspection and contaminate surfaces and food, making manipulation of raw organs and feeding of animals with raw lungs a potential source of infection for pets and owners.

Bayesian Assessment of the Accuracy of a PCR-Based Rapid Diagnostic Test for Bovine Tuberculosis in Swine

Infection with the Mycobacterium bovis (M. bovis) causes a disease referred to as bovine tuberculosis (bTB), which affects a wide range of mammal hosts. Many countries have implemented control and eradication plans that have resulted in variable levels of efficacy and success. Although bTB is a notifiable disease in Argentina, and a control plan that targets cattle herds has been in place for decades, M. bovis is still prevalent in cattle, swine, and certain wild species. The aim of the paper here was to assess the sensitivity (Se), specificity (Sp), and positive and negative predictive values (PPV and NPV) of PCR from tissue, which is a test for rapid M. bovis detection in swine. Bacteriological culture was also performed for comparison purposes. A Bayesian approach was applied to estimate the accuracy of the diagnostic tests, PCR and bacteriological culture, in 266 swine samples with bTB-like lesions recovered during routine official inspections at slaughterhouses. A one-population model, assuming conditional dependence between test results, and incorporating prior information on the performance of the tests obtained from the literature, was used to estimate the tests Se and Sp. The accuracy of the combined (in parallel) application of both tests was also estimated. The Se of the PCR (82.9%) was higher than the Se of the bacteriological culture (79.9%), whereas the Sp of both tests was similar (88.5 and 89.0%, respectively). Furthermore, when both techniques were assessed in parallel, the Se of the diagnostic system increased substantially (Se = 96.6%) with a moderate Sp loss (Sp = 78.8%; PPV = 92.8%; NPV = 89%). Results suggest that the PCR, or the combined application of bacteriological culture and PCR, may serve as an accurate diagnostic tool to confirm bTB in swine samples. Results here will help the design and implementation of effective surveillance strategies for the disease in swine of Argentina and other settings in which the disease is prevalent.

Detection of Viable Mycobacterium bovis in Lungs and Livers Sold in Butchers' Shops in Buenos Aires, Argentina

Although Mycobacterium bovis is the major etiological agent of tuberculosis in bovines, it can infect other mammalians. Previously reported cases of tuberculosis caused by M. bovis in cats from the Autonomous City of Buenos Aires (CABA) led to the conclusion that the main source of infection for these felines was the ingestion of raw bovine lungs. Thus, for this study, we collected samples of bovine viscera from butchers' shops of the Greater Buenos Aires (GBA) and the CABA to assess presence and viability of these mycobacteria in bovine lungs (including the lymph nodes) and livers. We analyzed 216 different samples and obtained 5 isolates of M. bovis (4 from lungs and 1 from liver) by culture analysis. We also confirmed the presence of different isolates by polymerase chain reaction, spoligotyping, and MIRU-VNTR assays. The results obtained in this work emphasizes the need of social education for food hygiene, and to change the habit of feeding pets with raw viscera, which carries the risk of epizootic and zoonotic transmission. Moreover, control and eradication programs of bovine tuberculosis should be strengthened and improved.