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Malignant catarrhal fever (MCF) is a severe, multisystemic, and usually fatal disease. In Brazil, MCF is frequently diagnosed in cattle and associated with OvHV-2. This study described the clinical and epidemiological characteristics, necropsy findings, and genetic identification of OvHV-2. Two outbreaks of MCF were identified in cattle in the western region of Rio Grande do Sul, Brazil, where only one animal was affected on each farm. The clinical signs observed were apathy, anorexia, bilateral corneal opacity, motor incoordination, decubitus, and pedaling movements. Macroscopic alterations included secretions and crusts in the nasal and ocular regions, the udder and vulva, and corneal opacity. Molecular analysis confirmed the wide distribution of OvHV-2 in the tissues of the affected animals. Sequencing of the amplified fragment showed that the two samples are genetically similar to others identified in cattle, grouping them with viruses of North American and Brazilian origin. The findings contribute to our knowledge of the disease and the molecular identity of the samples in the two outbreaks diagnosed. RESUMO: A febre catarral maligna (FCM) é uma doença severa, multissistêmica e geralmente fatal. No Brasil, a FCM é frequentemente diagnosticada em bovinos e associada com o OvHV-2. Esse estudo descreve as características clínicas, epidemiológicas, achados de necropsia e da identificação genética do OvHV-2. Foram identificados dois surtos de FCM em bovinos na região oeste do Rio Grande do Sul, Brasil, onde apenas um animal adoeceu em cada propriedade. Os sinais clínicos observados foram apatia, anorexia, opacidade bilateral de córnea, incoordenação motora, decúbito e movimentos de pedalagem. As alterações macroscópicas cursaram com secreções e crostas na região nasal e ocular, crostas na região do úbere e vulva e opacidade de córnea. A análise molecular confirmou a ampla distribuição do OvHV-2 nos tecidos dos animais afetados. O sequenciamento do fragmento amplificado mostrou que as duas amostras são geneticamente semelhantes entre si e a outras identificadas em bovinos, agrupando-se com vírus de origem americana e brasileira. Os achados contribuem para o conhecimento da doença e da identidade molecular das amostras presente nos dois focos diagnosticados.

This study investigated the cause of an outbreak of an acute respiratory disease syndrome followed by episodes of diarrhea in a dairy cattle herd from Southern Brazil. Deep nasal swabs (DNS) from asymptomatic calves, calves with pulmonary discomfort, and diarrheic calves after episodes of respiratory distress were used in molecular assays designed to detect the principal pathogens associated with bovine respiratory disease (BRD). Fecal samples were used for the molecular detection of bovine enteric disease agents. Pulmonary tissues from three calves and a cow that died were evaluated by molecular assays to identify 11 agents associated with the development of BRD. The intestinal and pulmonary fragments of one calf and the cow revealed atrophic enteritis and interstitial pneumonia by histopathology, respectively. Immunohistochemistry (IHC) identified intralesional antigens of a malignant catarrhal fever virus, genus Macavirus , within epithelial cells of the lungs and intestines. Molecular assays amplified ovine gammaherpesvirus 2 (OvGHV2) from most of the DNS, and the pulmonary and intestinal fragments from the animals that died, confirming that the Macavirus identified by IHC was OvGHV2. Concomitant pulmonary infections of OvGHV2 with bovine gammaherpesvirus 6 and bovine coronavirus were identified. Additionally, bovine viral diarrhea virus 1b and Aichivirus B were detected in the fecal samples. These findings demonstrated that OvGHV2, a Macavirus , was the disease agent most frequently (81.2%; 13/16) associated with singular pulmonary infections during this outbreak of BRD, suggesting that this virus may be another potential agent of respiratory disease of cattle.

The taxonomy of herpesviruses has been updated by the International Committee on Taxonomy of Viruses (ICTV). The former family Herpesviridae has been split into three families, which have been incorporated into the new order Herpesvirales . The revised family Herpesviridae retains the mammal, bird and reptile viruses, the new family Alloherpesviridae incorporates the fish and frog viruses, and the new family Malacoherpesviridae contains a bivalve virus. Three new genera have been created in the family Herpesviridae , namely Proboscivirus in the subfamily Betaherpesvirinae and Macavirus and Percavirus in the subfamily Gammaherpesvirinae . These genera have been formed by the transfer of species from established genera and the erection of new species, and other new species have been added to some of the established genera. In addition, the names of some nonhuman primate virus species have been changed. The family Alloherpesviridae has been populated by transfer of the genus Ictalurivirus and addition of the new species Cyprinid herpesvirus 3 . The family Malacoherpesviridae incorporates the new genus Ostreavirus containing the new species Ostreid herpesvirus 1 .

Ovine gammaherpesvirus 2 (OvHV-2), a member of the genus Macavirus, causes sheep-associated malignant catarrhal fever (SA-MCF), a fatal lymphoproliferative disease affecting a wide variety of ungulates in addition to horses. This study described an outbreak of SA-MCF in Mexico and the identification of the OvHV-2 virus in primary rabbit testis cultures through the generation of intranuclear inclusion bodies, syncytia, immunofluorescence (IF), immunocytochemistry (ICC), immunohistochemistry (IHC), endpoint polymerase chain reaction (PCR), and partial sequencing of the ORF75 gene. The animals involved in this outbreak showed mucogingival ulcers in the vestibule of the mouth and tongue, hypersalivation, corneal opacity, reduced food consumption, and weight loss of variable severity. These clinical signs and the histopathological findings suggested the diagnosis of SA-MCF. Buffy coat fractions from the anticoagulated blood samples of ill animals were collected and analyzed by PCR. Positive buffy coats were used to inoculate the primary cell cultures of rabbit testis to identify the virus. Small clusters of refractile cytomegalic cells, characteristic of viral cytopathic effects, were observed between 48 and 72 h post-infection. Furthermore, intranuclear acidophilic inclusion bodies (IBs) were identified in the inoculated primary culture cells, and the cytoplasm showed immunoreactivity with hyperimmune rabbit serum against OvHV-2. Moreover, in the liver histological sections from sick deer, immunoreactive juxtanuclear IBs were identified with the same rabbit hyperimmune serum. The obtained sequences were aligned with the OvHV-2 sequences reported in GenBank and revealed a nucleotide identity higher than 98%. Based on the evidence provided in this study, we conclude that the outbreak of SA-MCF in the municipality of Tequisquiapan in the state of Queretaro, Mexico, was caused by OvHV-2. This is the second study reporting that horses are susceptible to OvHV-2 infection and can develop SA-MCF. We identified for the first time in Mexico, the presence of OvHV-2 in buffy coats from horses and Artiodactyla.

Introduction: Ovine gammaherpesvirus 2 (OvGHV2) is the cause of sheep-associated malignant catarrhal fever (SA-MCF). Although SA-MCF is endemic in most geographical regions of Brazil, outbreaks are more frequently reported in the State of Rio Grande do Sul (RS). This report describes the findings of an SA-MCF outbreak in cattle from RS and investigates the possible reasons for the elevated occurrence of outbreaks in cattle from this geographical region of Brazil. Methodology: An outbreak of SA-MCF involving a 7-month-old dairy calf died acutely after presenting fever, profuse salivation, and respiratory difficulties. This calf was maintained on a farm that contained two asymptomatic sheep. A qPCR assay detected OvGHV2 DNA in multiple organs of the dead calf and blood from the two asymptomatic sheep. Results: These findings confirmed OvGHV2-related infection in the calf and the participation of the two sheep as possible disseminators of this infection. A sheep:cattle ratio (SCR) that evaluated the chances of SA-MCF outbreaks to occur within the mesoregions of RS where cattle and sheep are reared simultaneously, demonstrated that geographical regions with an SCR > 0.15 have a significantly increased chance to develop outbreaks of SA-MCF in cattle relative to mesoregions with an SCR < 0.15 within RS. Conclusions: The SCR may be used as a possible indicator for the occurrence of SA-MCF outbreaks in cattle within the state of Rio Grande do Sul. Additionally, the traditional sheep production system and rearing practiced within RS seem to favor the development of SA-MCF outbreaks in susceptible cattle populations.

Introduction: Sheep associated-malignant catarrhal fever is a frequently fatal, lymphoproliferative, and vascular disease caused by ovine gammaherpesvirus 2 (OvGHV2), a member of the malignant catarrhal fever virus (MCFV) complex. OvGHV2-related epidemics normally have reduced morbidity with elevated lethality. Methodology: This study investigated the causes of elevated morbidity, mortality, and lethality in cattle maintained on Brachiaria grass pastures and with neurological and enteric disease syndromes from nine farms in Paraná, Southern Brazil. Results: The principal histopathological findings included necrotizing lymphocytic vasculitis, proliferative vascular lesions, and toxic cholangiohepatitis. An immunohistochemical (IHC) assay utilizing the 15A monoclonal antibody (15A-MAb), which is specific for MCFV, revealed positive intracytoplasmic immunoreactivity within the epithelial cells of the lungs, intestine, liver, and kidneys in most animals, confirming infections by MCFV. PCR detected singular infections by OvGHV2 (n = 3) and bovine gammaherpesvirus 6 BoGHV6 (n = 3) in cattle with positive intracytoplasmic immunoreactivity by the 15A-MAb IHC assay. In one animal with positive immunoreactivity to the 15A-MAb IHC assay, neither Macavirus was identified through molecular testing. Conclusions: These findings suggested that these two Macavirus were associated with the positive IHC findings. Additionally, the non-detection of OvGHV2 and BoGHV6 in the organs of one animal, despite typical vascular lesions and with positive IHC results, suggests that another Macavirus may be involved. Moreover, the identification of BoGHV6 DNA in cattle not infected by OvGHV2 but containing MCFV antigens, indicates cross-reactivity of BoGHV6 with the 15A-MAb assay. The possibe role of Bracharia on the occurrence of these infections is discussed.

Background Viruses within the γ-herpesviruses subfamily include the causative agents of Malignant Catarrhal Fever (MCF) in several species of the order Artiodactyla . MCF is a usually fatal lymphoproliferative disease affecting non-adapted host species. In adapted host species these viruses become latent and recrudesce and transmit during times of stress or immunosuppression. The undetected presence of MCF-causing viruses (MCFVs) is a risk to non-adapted hosts, especially within non-sympatric zoological collections. This study investigated the presence of MCFVs in six different zoological collections in the UK, to evaluate the presence of subclinical/latent MCFVs in carrier animals. Methods One-hundred and thirty eight samples belonging to 54 different species of Artiodactyla were tested by Consensus Pan-herpes PCR. The positive samples were sequenced and subjected to phylogenetic analyses to understand their own evolutionary relationships and those with their hosts. Results Twenty-five samples from 18 different species tested positive. All viruses but one clustered in the γ-herpesvirus family and within the Macavirus as well as the non-Macavirus groups ( caprinae and alcelaphinae / hippotraginae clusters, respectively). A strong association between virus and host species was evident in the Macavirus group and clustering within the caprinae group indicated potential pathogenicity. Conclusion This study shows the presence of pathogenic and non-pathogenic MCFVs, as well as other γ-herpesviruses, in Artiodactyla species of conservation importance and allowed the identification of new herpesviruses in some non-adapted species.

This report investigated the cause of cattle mortality in two farms in Southern Brazil. The tissues of one animal from each farm (animals #1 and #2) respectively were used in pathological and molecular investigations to determine the possible cause of death. The principal pathological findings observed in animal #1 were pulmonary, myocardial, and encephalitic hemorrhages with vasculitis, and lymphoplasmacytic interstitial pneumonia with proliferative vascular lesions (PVL). The main pathological findings observed in animal #2 were purulent bronchopneumonia, hemorrhagic myocarditis, and lymphoplasmacytic interstitial pneumonia with PVL. An immunohistochemical assay detected intralesional antigens of a malignant catarrhal fever virus (MCFV) from multiple tissues of animal #2 while PCR confirmed that the MCFV amplified was ovine gammaherpesvirus 2 (OvGHV2), genus Macavirus , subfamily Gammaherpesvirinae ; OvGHV2 was also amplified from multiple tissues of animal #1. Furthermore, PCR assays amplified Histophilus somni DNA from multiple fragments of both animals. However, the nucleic acids of Mannheimia haemolytica , Pasteurella multocida , Mycoplasma bovis , bovine respiratory syncytial virus, bovine alphaherpesvirus virus 1 and 5, bovine coronavirus, and bovine parainfluenza virus 3 were not amplified from any of the tissues analyzed, suggesting that these pathogens did not participate in the development of the lesions herein described. These findings demonstrated that both animals were concomitantly infected by H. somni and OvGHV2 and developed the septicemic and encephalitic manifestations of H. somni . Furthermore, the interstitial pneumonia observed in cow #2 was more likely associated with infection by OvGHV2.

Ovine gammaherpesvirus 2 (OvGHV2) is a Macavirus and the cause of sheep-associated malignant catarrhal fever (SA-MCF) in susceptible mammalian hosts worldwide. OvGHV2 may produce typical clinical manifestations of SA-MCF or subclinical infections. Additionally, OvGHV2 is associated with cutaneous lesions in ruminants, with few documented reports of this unusual manifestation worldwide. This paper presents the pathological, immunohistochemical (IHC), and molecular findings observed in outbreaks of OvGHV2-related skin infections in dairy cattle from Southern Brazil. Cutaneous scrapings (n = 35) and biopsies (n = 6) were obtained from dairy cows derived from three farms. All cows (n = 35) developed widespread, ulcerative to scaly and erythematous skin lesions, and had no contact with sheep or goats. The biopsies were evaluated for histopathological diagnosis and then used in IHC analyses designed to detect malignant catarrhal fever virus (MCFV) antigens and to evaluate the inflammatory response. All scrapings and biopsies were used in PCR assays to amplify OvGHV2. Additionally, all biopsies were used in PCR assays to detect bovine gammaherpesvirus 6 (BoGHV6), bovine alphaherpesvirus 1 (BoAHV1), and poxvirus. Histopathology revealed chronic folliculitis in all biopsies. IHC detected intralesional, intracytoplasmic MCFV antigens in most (83.3%; 5/6) of the cutaneous lesions with folliculitis. These skin lesions showed a strong T-cell response, macrophage clusters, and caspase-positive follicular keratinocytes. OvGHV2 DNA was detected in 66.7% (4/6) of the cutaneous biopsies that contained MCFV antigens and in 8.6% (3/35) of the cutaneous scrapings. The DNA of BoGHV6, BoAHV1, and Poxvirus was not amplified from any of the cutaneous biopsies. These findings demonstrated that OvGHV2 was associated with the cutaneous lesions in dairy cows at these farms and represent the first description of OvGHV2-related skin disease in ruminants from Brazil and the entire Latin America. A review of previous cases of skin lesions associated with infections by OvGHV2 revealed that most cases had a histological diagnosis of folliculitis, suggesting that folliculitis may be associated with OvGHV2-related skin infections. Additionally, this investigation contrasts all previous reports of OvGHV2-related skin disease in ruminants, since the infected cows herein identified were not reared concomitantly or within proximity of the asymptomatic reservoir host. Furthermore, the possible form of OvGHV2 dissemination to the susceptible cows during this study is discussed.

Ovine gammaherpesvirus 2 (OvGHV2) is a member of Macavirus genus, subfamily Gammaherpesvirinae , family Herpesviridae , and causes sheep associated-malignant catarrhal fever (SA-MCF) in a wide range of ungulates. However, no descriptions of SA-MCF and/or infections due to OvGHV2 were identified in the wild boar ( Sus scrofa ). This study investigated the occurrence of OvGHV2 in the lungs (n = 44) of asymptomatic, free ranging wild boars captured in several regions of Paraná State, Southern Brazil. A PCR assay targeting the OvGHV2 tegument protein gene amplified OvGHV2 DNA in 4.55% (2/44) of the pulmonary tissues evaluated. Sequence analysis confirmed that the OvGHV2 strains herein identified have 98.4% deduced amino acid (aa) sequence identity with the prototype strain of OvGHV2 and 96.4–100% aa identity with similar strains of OvGHV2 detected in several animal species from diverse countries. These findings confirmed that these two wild boars were infected by OvGHV2, represent the first description of this infection in these animals, and add to the number of pathogens identified in this animal species. Furthermore, these findings contrast earlier descriptions of OvGHV2 in swine since in all previous reports the infected pigs demonstrated clinical manifestations of disease. Consequently, these wild boars from Southern Brazil were subclinically infected or suffered asymptomatic infections by OvGHV2.