Histophilus somni -associated syndromes in sheep from Southern Brazil

Abstract

Histophilus somni is a Gram-negative bacterium that is associated with a disease complex (termed histophilosis) that can produce several clinical syndromes predominantly in cattle, but also in sheep. Histophilosis is well described in North America, Canada, and in some European countries. In Brazil, histophilosis has been described in cattle with respiratory, reproductive, and systemic disease, with only one case described in sheep. This report describes the occurrence of Histophilus somni-associated disease in sheep from Southern Brazil. Eight sheep with different clinical manifestations from five farms were investigated by a combination of pathological and molecular diagnostic methods to identify additional cases of histophilosis in sheep from Brazil. The principal pathological lesions were thrombotic meningoencephalitis, fibrinous bronchopneumonia, pulmonary abscesses, and necrotizing myocarditis. The main clinical syndromes associated with H. somni were thrombotic meningoencephalitis (n = 4), septicemia (n = 4), bronchopneumonia (n = 4), and myocarditis (n = 3). H. somni DNA was amplified from multiple tissues of all sheep with clinical syndromes of histophilosis; sequencing confirmed the PCR results. Further, PCR assays to detect Pasteurella multocida and Mannheimia haemolytica were negative. These findings confirmed the participation of H. somni in the clinical syndromes investigated during this study, and adds to the previous report of histophilosis in sheep from Brazil.

Infectious Disease Agents Associated with Pulmonary Alterations in Aborted Bovine Fetuses

“…Collectively, fetal infection by these pathogens was probably due to intrauterine infection resulting from transplacental transmission [40,41]. Consequently, most of the disease agents herein identified may be classified either as primary or secondary fetopathic agents of cattle [24,40] and could have produced direct or indirect effects on fetal survival [41]. The primary fetopathy agents herein identified (BVDV, BoAHV1, N. caninum, B. abortus, and Leptospira spp.)…”

“…Furthermore, some well-known pathogens of reproductive disease in cattle, such as BVDV, BoAHV1, Leptospira spp., B. abortus, and M. bovis, were also identified and associated with pulmonary alteration(s), collaborating with the results of previous studies that have demonstrated B. abortus [19,20], M. bovis [17], BoAHV1 [16,21], BVDV [10] in the fetal lungs of cattle. Collectively, fetal infection by these pathogens was probably due to intrauterine infection resulting from transplacental transmission [40,41]. Consequently, most of the disease agents herein identified may be classified either as primary or secondary fetopathic agents of cattle [24,40] and could have produced direct or indirect effects on fetal survival [41].…”

“…The primary fetopathy agents herein identified (BVDV, BoAHV1, N. caninum, B. abortus, and Leptospira spp.) can cross the placental barrier, producing fetal disease in healthy cows, whereas the secondary or opportunistic agent (H. somni) crosses the placental barrier when there is placental damage, alteration to the microflora of the reproductive tract, or in immunocompromised cows [40].…”

Use of non-steroidal anti-inflammatory drugs in the treatment of bacterial respiratory tract infections of lambs

“…The sheep strain of H. somni can infect cattle and goats, while the cattle strain cannot infect sheep 3. [19][20][21]…”

Mineral drench inhalation as a complication of dosing in young lambs

“…H somni ‐associated disease is more commonly reported in cattle but cases of meningoencephalitis, bronchopneumonia, septicaemia and myocarditis have been recorded in sheep 1 …”