A Case of Generalized Bovine Tuberculosis in a Sheep

Abstract

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...

Scientific Opinion on the public health hazards to be covered by inspection of meat from sheep and goats

“…The presence of mycobacteria has been previously reported in the small ruminant population in the EU (Domenis et al, 2011;Malone et al, 2003;Marianelli et al, 2010;. Despite these reports, evidence of meat-borne transmission of these pathogens to humans from small ruminants is lacking, so this potential pathway of infection remains unproven in the context of livestock processed through the EU meat inspection system.…”

Tuberculosis due to Mycobacterium bovis and Mycobacterium caprae in sheep

“…Tuberculosis (TB) in sheep, caused by members of the Mycobacterium tuberculosis complex (MTC), has been reported in New Zealand, Sudan, Italy, Ireland and the United Kingdom (Cordes et al, 1981;Davidson et al, 1981;Tag El Din and Nour Gamaan, 1992;Malone et al, 2003;Marianelli et al, 2010;Van Der Burgt, 2010). Ten clinical cases of TB have been reported previously in sheep in Spain: four in Aragón (M. bovis and M. caprae), four in Salamanca (M. bovis, spoligotype SB0124), one in Cataluña (M. bovis, SB0415) and one in Huelva (M. caprae, SB0157) (García Marín et al, 1989;Gutiérrez et al, 1997; MARM/VISAVET-Spanish Database of Animal Mycobacteriosis mycoDB 1 ).…”

Situação da tuberculose em ovinos consorciados com bovinos leiteiros na região sudoeste maranhense

“…Porém, várias pesquisas no Brasil e no mundo comprovam que a espécie pode contrair a enfermidade a partir de outros animais (KASSA et al, 2012;MALONE et al, 2003;MARIANELLI et al, 2010, MENDONZA et al, 2012TSCHOPP et al, 2011;VAN DER BURGT et al, 2013). ALLEN (1988) destacou que, embora o pequeno número de casos de tuberculose ovina possa ser confundido com outras doenças mais comuns das ovelhas, é provável que uma combinação de fatores comportamentais e de criação possa tornar a doença em ovelhas extremamente rara, independentemente do verdadeiro nível de suscetibilidade.…”