Bovine tuberculosis (bTB) is an emerging disease among wild animals in many parts of the world. Wildlife reservoir hosts may thus represent a potential source of infection for livestock and humans. We investigated the role played by the Sicilian black pig, an autochthonous free- or semi-free-ranging domestic pig breed, as a potential source of bTB infection in an area where bTB prevalence in cattle is high. We initially performed a preliminary field study to assess the occurrence of bTB in such animals. We sampled 119 pigs at abattoir and found 6.7% and 3.4% of them to be affected by gross tuberculous-like lesions (TBL) and Mycobacterium bovis culture positive, respectively. We then proceeded to investigate the dissemination and characteristics of lesions in a second field study performed on 100 animals sampled from infected herds. Here, tissues collected at the abattoir were examined macroscopically, microscopically, and by culture tests. Most pigs with TBL showed generalized lesions in both gross and histological examinations (53% and 65.5%, respectively). Head lymph nodes were the most frequently affected in both localized and generalized TB cases observed macroscopically and microscopically. M. bovis was the most frequently isolated etiologic agent. The molecular characterization of isolates from both field studies by spoligotyping and analysis of 12 mycobacterial interspersed repetitive-unit-variable number tandem repeat (MIRU-VNTR) loci, followed by their comparison to isolates of cattle origin, suggested a potential transmission of mycobacteria from domestic animals to black pigs and vice versa. Our findings, along with ethological, ecological, and management considerations, suggest that the black pig might act as a bTB reservoir in the ecosystem under study. However, additional studies will be necessary to establish the true epidemiological significance of the Sicilian black pig.
Anaplasma species are transmitted by ticks and cause diseases in humans and animals. These pathogens infect sheep, an economically important domestic animal worldwide. The current study was designed to characterize in 200 animals the infection with Anaplasma phagocytophilum and Anaplasma ovis and the genetic diversity of A. ovis strains collected from a naturally infected sheep flock with poor health condition. Sheep had 98% seroprevalence to Anaplasma spp. antibodies. PCR results confirmed the presence of A. phagocytophilum and A. ovis DNA in 11.5% and 37% of the sheep, respectively. Concurrent infections were detected in 6.5% of the sheep. Seventy-one adult ticks were collected from 45 sheep with infestations ranging from one to 15 ticks per animal. The analysis of A. ovis msp4 sequences demonstrated a previously unreported polymorphism for this pathogen with 17 different haplotypes in infected sheep. These results demonstrated that, although A. ovis msp4 haplotypes may be less variable when compared with Anaplasma marginale and A. phagocytophilum strains on a global scale, genetic polymorphisms occur in this locus in strains obtained from an infected sheep flock with poor health condition.
Abstract. The present report describes a rare case of generalized bovine-type tuberculosis in a slaughtered 4-year-old ewe discovered during routine surveillance at an abattoir. A postmortem examination revealed lesions in the ewe's thoracic and abdominal cavities, ranging from encapsulated, mineralized foci to extensive, soft, caseous tissue. Lesions in the lungs, liver, and lymph nodes were consistent with mycobacterial infection. A histopathological examination detected granulomatous lesions in all tissue samples. The presence of Mycobacterium tuberculosis complex genome was confirmed through a polymerase chain reaction (PCR) analysis of tissues, using IS6110 primers, followed by a nucleotide sequence analysis of PCR products. Acidfast bacteria, characterized as Mycobacterium bovis, were isolated from lesions following 38 days of incubation.Key words: Mycobacterium bovis; polymerase chain reaction; sheep; tuberculosis.Mycobacterium bovis, the etiological agent of bovine-type tuberculosis (TB), has an exceptionally wide host range 8 and a complex epidemiological pattern of infection, involving interaction between humans and domestic and wild animals. Information on TB in sheep is scarce, and the general picture that emerges is far from conclusive. In a previous study, postmortem examinations on 70 tuberculinreacting sheep were carried out. 6 Tuberculous lesions similar to those of cattle were found in 61% of cases. Mycobacterium bovis was also recovered from 32 of 43 sheep with tuberculous lesions in a previous study.5 These animals belonged to a flock numbering 15,000 head, grazing on a farm with a history of widespread occurrence of TB in both cattle and possums. In a 1988 study, only 2 sheep with histological lesions typical of TB were observed in an abattoir survey of 9.9 million lambs and 1.97 million adult sheep.1 In another study, an outbreak of M. bovis in a flock of sheep housed in close contact with tuberculous cattle was described.10 Gross TB lesions were present in 4 of the 6 tuberculin-reacting sheep, and M. bovis was isolated from the lesions. Clinically, however, all affected sheep were healthy. The isolation of M. bovis from a sheep with tuberculous lesions, belonging to a flock of 200 ewes, has also been previously reported. 9In the current study, a rare case of generalized TB in a slaughtered 4-year-old ewe, discovered during routine surveillance at an abattoir, is described. The ewe in question belonged to a flock of 350 clinically healthy sheep bred on a Sicilian farm where cattle and goats were absent.Samples for histopathological, molecular, and culture examinations were taken from the ewe's submandibular, mesenteric, and mediastinal lymph nodes, as well as from organs with lesions compatible with TB, namely, diaphragm, lungs, and liver. Tissues were fixed in 10% buffered formalin and processed in 4-mm paraffin-embedded sections for histology. Four-micrometer sections were cut and stained with Ziehl-Neelsen and hematoxylin and eosin for histological examination. Gram and Grocott stains we...
Wild ruminants have an important role in the epidemiology of bovine tuberculosis (bTB). This study describes an outbreak of bovine tuberculosis occurring in a fallow deer herd in Sicily. In 2012 a Sicilian herd of 47 animals was referred for cachexia. Pathological examination of 2 dead animals revealed disseminated granulomas predominantly involving the skin and subcutaneous tissues. Tissue samples were submitted for histological analysis, bacteriological culture, and biomolecular assay. PCR analysis identified Mycobacterium strains. Genotyping by spoligotyping and MIRU-VNTR profiles identified Mycobacterium bovis spoligotype SB0120 in both animals. In 2014, bTB skin testing of 28 fallow deer from the same group was positive in 4 and inconclusive in another 4. All 8 positive/inconclusive reactors were euthanized. Disseminated granulomatous lesions were noted in 6 of these animals, 3 of which (2 positive and 1 negative to skin tests) also presented cutaneous lesions. M. bovis spoligotype SB0120 was identified from all animals in which tuberculous-like lesions were observed, including 2 negative reactors. Many of the animals involved in this outbreak presented diffuse skin lesions, a potential route of transmission of M. bovis infection. Given the epidemiological role wildlife play in the maintenance of bTB infection and its potential risk for humans, a comprehensive monitoring plan for this zoonosis in wildlife species in Sicily is needed.
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