Malignant Catarrhal Fever in Brazilian cattle presenting with neurological syndrome

Abstract

Malignant Catarrhal Fever (MCF) was investigated in the central nervous system of cattle with neurological syndrome. Two-hundred-ninety samples were analyzed by histology, and molecular methods to detect ovine herpesvirus type 2 (OvHV-2) were optimized and validated. The qualitative polymerase chain reaction (qualitative PCR) analytical sensitivity was 101 DNA copies/μL and found 4.8% (14/290) positive for OvHV-2. The quantitative polymerase chain reaction (qPCR) analytical sensitivity was 100 DNA copy/μL and 5.9% (17/290) positivity, with 47.1% (8/17) of the positive samples presenting histological evidence of non-purulent meningo-encephalitis. The qualitative PCR products (422 bp of the ORF75 region) were sequenced and submitted to phylogenetic analysis. Identity matrices showed 100% similarity in OvHV-2 samples obtained in this study and those recovered from GenBank, corroborating other studies.

Ovine gammaherpesvirus 2 infections in cattle without typical manifestations of sheep-associated malignant catarrhal fever and concomitantly infected with bovine coronavirus

“…Furthermore, our group has demonstrated the participation of OvHV-2 in cattle with neurological syndromes but without typical clinical manifestations of SA-MCF [ 15 ], with similar findings in cattle with pulmonary [ 19 , 20 , 22 ] and renal [ 21 ] diseases. Additionally, several reports have confirmed the participation of OvHV-2 in cattle [ 13 , 16 , 45 , 46 ] and the American bison [ 16 – 18 ] without typical clinical manifestations of SA-MCF. Moreover, it was suggested that infected animals without typical SA-MCA may be subclinically infected by OvHV-2 [ 16 ].…”

“…The clinical manifestations associated with SA-MCF are easily recognized by practicing veterinarians [ 1 , 3 ], so a clinical diagnosis of SA-MCF is readily achieved when typical signs are present in affected animals. The clinical syndromes of SA-MCF in ruminants include the classical head and eye form [ 1 , 9 , 10 ], in addition to the alimentary [ 9 ], chronic [ 11 , 12 ], neurological [ 13 , 14 ], peracute, and cutaneous [ 1 , 2 ] manifestations of MCF. Moreover, abrupt fever (> 41 °C) is characteristic of MCF [ 1 ], even in the alimentary form in which severe diarrhea may be present [ 9 ].…”

“…Moreover, abrupt fever (> 41 °C) is characteristic of MCF [ 1 ], even in the alimentary form in which severe diarrhea may be present [ 9 ]. Additionally, cattle with neurological manifestations [ 13 , 15 ], and healthy cows [ 13 , 15 ] and the American bison, Bison bison [ 16 – 18 ] developed typical SA-MCF histologic lesions but without clinical signs suggestive of MCF. Furthermore, intralesional antigens of MCFV were identified in cattle with bovine respiratory disease, BRD [ 19 ], pulmonary [ 20 ], and renal diseases [ 21 ], but without any clinical manifestation and/or diagnosis of MCF, suggesting that these animals were infected by OvHV-2 but without the characteristic clinical signs of SA-MCF.…”

An outbreak of malignant catarrhal fever in Sambar deer (Rusa unicolor)

“…Diagnoses were carried out in Uruguay (Preliasco et al 2013). In Brasil, there were reported cases of MCF in cattle in the Northeast (Döbereiner & Tokarnia 1959, Macêdo et al 2007, Peixoto et al 2015, Mid-West (Mendonça et al 2008, Furlan et al 2012, Lemos et al 2005, Ribas et al 2013, Southeast (Lemos et al 2005, Martins et al 2017, Galvão et al 2016 and South region (Barros et al 1983, Garmatz et al 2004. In buffaloes, MCF was diagnosed in Minas Gerais (Costa et al 2009).…”

Detection and characterisation of sheep-associated malignant catarrhal fever infection from ruminants by using tegument and gB gene sequences of OvHV-2

“…The clinicopathological findings of MCF in affected animals are not clear about differential diagnoses. Recently, new forms, neurological syndrome and systemic necrotising vasculitis, have been described that make determining clinical pictures and diagnosing the disease difficult (Martins et al 2017 ; Pesavento et al 2019 ). Famous findings have described high fever, generalised lymphadenopathy, keratoconjunctivitis, corneal oedema and opacity, but these symptoms are not always evident (Plowright 1990 ).…”