Cases Of Malignant Catarrhal Fever Research Articles

Coding complete genome of a strain of ovine herpesvirus-2 associated with a clinical case of malignant catarrhal fever in a domestic lamb.

Ovine herpesvirus-2 causes sheep-associated malignant catarrhal fever, a fatal disease of ruminants and pigs. The virus is carried by sheep, and infection is typically subclinical. Here, we report the coding complete genome sequence of a strain of OvHV-2 obtained from a clinically affected domestic lamb.

Case Reports: Clinical features and postmorteum findings of sheep-associated malignant catarrhal fever in a 2-years old bull

Malignant Catarrhal Fever (MCF) is a fatal lymphoproliferative disease of cattle and other ungulates caused by alcelaphine herpesvirus 1 (AlHV-1) and ovine herpesvirus 2 (OvHV-2), the main causative agents of wildebeest-associated MCF (WA-MCF) and sheep-associated MCF (SA-MCF), respectively. The virus is mainly spread by aerosols from pregnant or newborn sheep, goats, and wildebeest to susceptible animals. This case report presents the clinical features and post-mortem findings of an unusual case of malignant catarrhal fever (MCF) in a two-year-old bull brought to the Professor Feseha Gebreab Memorial Veterinary Teaching Hospital in Bishoftu, Ethiopia. The bull was semi-intensively managed, co-housed, and fed with sheep and other domestic animals. The animal was shivering upon arrival, with naso-ocular discharge and clouding of the eyes. The bull was febrile, with a rectal body temperature of 41.4 oC and a respiratory and heart rate of 40 and 48 beats per minute, respectively. On physical examination, the bull was emaciated, with bilateral yellowish mucopurulent naso-ocular discharge, frequent blinking, bilateral corneal opacity, salivation, a foamy mouth, head pressing, and enlargement of superficial lymph nodes. Malignant catarrhal fever was suspected based on the history and clinical signs, and empiric therapy with 10% oxytetracycline, diclofenac, and IV fluid was initiated. The bull died after receiving the third day of treatment. At necropsy, hemorrhages were found in the esophagus, trachea, and small and large intestines. In the kidney, white foci, enlargement, and fatty degeneration were observed. An ulcerated lesion was seen on the abomasum. In the gall bladder, enlargement and vascularization were also noted. The current case report confirms the rare case of clinical SA-MCF based on the history, exhibited clinical pictures, post-mortem findings, and PCR results. Separation of cattle and sheep is strongly advised to prevent SA-MCF, as no vaccine has yet been developed.

Sheep Associated-Malignant Catarrhal Fever: Past, present, and future

Members of Artiodactyla can contract the infectious disease Malignant Catarrhal Fever (MCF), which has a wide range of symptoms. Ten known viruses contribute to the disease, the two most significant ones being Ovine gamma herpes virus 2 (OvHV-2) and Alcelaphine gamma herpes virus 1 (AIHV-1). In the African subcontinent, AIHV-1 is seen in most MCF cases. In the Indian scenario, Ovine gamma herpes virus-2 is the main culprit. MCF is reported in certain pockets of India. Its threat to wildlife is not yet completely understood. In AIHV-1, wildebeests serve as the primary MCF reservoir, whereas with OvHV-2, the primary MCF reservoir is sheep. In India, OvHV-2 causes MCF in deer species, bison, and water buffaloe. The life cycle and properties of this virus are not yet wholly deciphered. To understand the impact of the disease and the threat it may pose in the future, we need to have diagnostic techniques in place. Currently, PCR is the most commonly used diagnostic technique. Work should be done on field-oriented tests like ELISA and LFA, which are helpful in areas without sophisticated lab facilities. Treatment protocols must be in place, as culling bovines is not an accepted policy in India. Probable plans for overcoming all these problems are discussed in this article.

Malignant catarrhal fever in cattle in Spain

AbstractWe report a case of malignant catarrhal fever in cattle in a mixed herd (ovine/bovine). The case occurred in the Basque Country (north of Spain) in April 2021. The infection was confirmed by polymerase chain reaction in a calf that had developed signs consistent with the ‘head and eye’ form of the disease. Just before its appearance, a group of five calves born at the farm (including the affected one), aged between 8 and 12 months, were temporarily housed in a pen adjacent to the sheep shed, and separated by a metallic fence that allowed direct contact. In Spain, there are no data on the incidence of malignant catarrhal fever, as there is no active surveillance programme in place. Furthermore, the disease is uncommonly considered in differential diagnoses.

Sheep-Associated Malignant Catarrhal Fever: Role of Latent Virus and Macrophages in Vasculitis.

Malignant catarrhal fever (MCF) is a sporadic, generally fatal disease caused by gammaherpesviruses in susceptible dead-end hosts. A key pathological process is systemic vasculitis in which productively infected cytotoxic T cells play a major role. Nonetheless, the pathogenesis of MCF vasculitis is not yet clear. We hypothesized that it develops due to an interaction between virus-infected cells and immune cells, and we undertook a retrospective in situ study on the rete mirabile arteries of confirmed ovine gammaherpesvirus-2 (OvHV-2)-associated MCF cases in cattle, buffalo, and bison. Our results suggest that the arteritis develops from an adventitial infiltration of inflammatory cells from the vasa vasorum, and recruitment of leukocytes from the arterial lumen that leads to a superimposed infiltration of the intima and media that can result in chronic changes including neointimal proliferation. We found macrophages and T cells to be the dominant infiltrating cells, and both could proliferate locally. Using RNA in situ hybridization and immunohistology, we showed that the process is accompanied by widespread viral infection, not only in infiltrating leukocytes but also in vascular endothelial cells, medial smooth muscle cells, and adventitial fibroblasts. Our results suggest that OvHV-2-infected T cells, monocytes, and locally proliferating macrophages contribute to the vasculitis in MCF. The initial trigger or insult that leads to leukocyte recruitment and activation is not yet known, but there is evidence that latently infected, activated endothelial cells play a role in this. Activated macrophages might then release the necessary pro-inflammatory mediators and, eventually, induce the characteristic vascular changes.

Bir inekte Ovine Herpesvirüs-2’nin neden olduğu Sığır Gangrenli Nezlesi olgusu

Malignant catarrhal fever (MCF) has been defined as a viral disease of domestic cattle and wild ruminants. We report a case of MCF caused by ovine herpesvirus-2 (OvHV-2) in a 4-year-old female Holstein cow. Microscopic examination showed that fibrinoid necrotic vasculitis in all tissues and organs; inflammatory changes in the vessel walls of the brain (pons, cerebrum and meninges); ulcerative changes in the oral mucosa; mild inflammatory cell infiltrations around the glomeruli and interstitium in the cortex of the kidney; widespread edema between the muscle bundles in the heart. PCR was performed to determine the presence of ovine herpesvirus-2 nucleic acids and 386 bp product was obtained by primer sequences that replicated the Pol gene region of OvHV-2. This PCR finding confirmed our diagnosis as sheep-associated MCF (SA-MCF).

GENETIC DIVERSITY of OVINE HERPESVIRUS 2 STRAINS OBTAINED FROM MALIGNANT CATARRHAL FEVER CASES in EASTERN TURKEY

Malignant Catarrhal Fever (MCF) is a generalized, definitive lethal disease affecting the epithelial and lymphoid tissues of the respiratory and digestive tract, mainly cattle and some wild ruminants such as deer, buffalo or antelope. The sheep-related form of MCF is known to be present in Turkey and is caused by ovine herpesvirus 2 (OvHV-2). The aim of this study was to reveal the genetic diversity of OvHV-2 strains obtained from MCF cases in Eastern Turkey where the livestock industry has an important impact on economic activities. For this purpose, RTA (Replication and transcription activator), FGARAT (formylglycineamide ribotide amidotransferase) and some of glycoprotein genes (Ov7, Ov8 ex2, ORF27 and Ov9.5) were investigated in blood samples from 24 cattles, clinically diagnosed with MCF. Genomic data of chosen samples were furthermore used to characterize and undergo combined phylogenetic analysis to determine possible alleles and subvariants. The results showed that high level of OvHV-2 diversity existed in selected genes and strains carrying allelic variants might circulate both in two geographically distinct regions and in a region itself. Moreover, three different OvHV-2 types and various subtypes were identified based on multi locus approach. This study provides important data to epidemiological research and thereby helps to determine the source of the virus and understand the spread of the disease.

Malignant catarrhal fever: An emerging yet neglected disease in captive sika deer (Cervus nippon) herds in China.

Malignant catarrhal fever (MCF) is a fatal lymphoproliferative disease that represents a serious problem in the deer-rearing industry. To better understand an MCF-like disease that has emerged in northern China since 2015, we investigated ten cases by documenting clinical and epidemiological data and analysing causative agents and histopathological changes. In addition, a retrospective screen for Macavirus DNA and a questionnaire-based survey were conducted. Epizootic MCF in Chinese sika deer herds has emerged with a low morbidity of 3.8% (95% CI: 2.5%-5.1%) and a high mortality of 93.2% (95% CI: 86.6%-99.9%). The disease course varied from 3 to 12days. Aetiologically, OvHV-2 was predominant in the MCFV, accounting for most MCF cases (21/23). In contrast, only two CpHV-2 isolates were phylogenetically closely related to CpHV-2. Diarrhoea and nasal discharges were the most frequent manifestations, although clinical signs varied in some cases. Pathologically typical lesions of haemorrhage, necrosis and lymphoid cell infiltration were readily observed in a variety of organs. Vasculitis caused by vascular and perivascular lymphoid cell infiltration was common. The retrospective survey suggested a low positive rate (3/275) of MCFV DNA in peripheral blood lymphocytes (PBL). The questionnaire-based survey suggested the disease was neglected by local veterinarians, who did not acknowledge the risk of co-rearing deer with reservoir species. Collectively, the emerging epizootic MCF in Chinese sika deer herds remains neglected, emphasizing the urgency of initiating full-field diagnoses and control strategies.

Malignant Catarrhal Fever in Indonesia and Its Control Strategy

Malignant catarrhal fever (MCF) is an immunoproliferative and lethal disease of many species of the order Artiodactyla (such as families Bovidae, Cervidae and Suidae) caused by a member of the MCF virus (MCFV) group belongs to the genus Macavirus in the subfamily Gammaherpesvirinae. There are two types of MCF i.e. Wildebeest-Associated MCF (WA-MCF) which is caused by Alcelaphine Herpesvirus-1 (AlHV-1) with wildebeest as reservoir animal; and Sheep-Associated MCF (SA-MCF) which is caused by Ovine herpesvirus 2 (OvHV-2) with sheep and goats as reservoir animals. AlHV-1 virus has already been isolated whereas OvHV-2 has not been isolated so that vaccines are not yet available. Both types cannot be differentiated by clinical and pathological findings. This disease was previously diagnosed based on the epidemiological information and clinicopathological findings, but now it can be diagnosed by using molecular biological tests. This paper describes the epidemiology of MCF virus, MCF cases in Indonesia and efforts to control this disease. In Indonesia, SA-MCF cases have been reported almost in all provinces as endemic as well as epidemic nature. Separation of reservoir animal with susceptible species, "producing" a SA-MCF virus free sheep and attempt to develop a recombinant vaccine against SA-MCF is the main control strategy that can be suggested.

An Acute Multispecies Episode of Sheep-Associated Malignant Catarrhal Fever in Captive Wild Animals in an Italian Zoo.

In July 2011, in a zoological garden in Rome, Italy, malignant catarrhal fever (MCF), a fatal, systemic disease of Artiodactyla, was suspected on the basis of neurological signs and gross lesions observed in a banteng, the first animal to die of this infection. An MCF type-specific PCR with subsequent sequencing of the PCR amplicon confirmed the aetiological agent as ovine herpesvirus-2 (OvHV-2). Biological samples were collected from the dead animals for gross, histological, bacteriological, virological and serological examinations. An epidemiological investigation was conducted to identify the source of the outbreak, as further deaths due to OvHV-2 still occurred after the removal of the acknowledged reservoirs, domestic sheep and goats. For this purpose, samples from other susceptible species and reservoir hosts were collected for virological and serological analysis. In conjunction, a retrospective sero-investigation was conducted on sera collected between 1999 and 2010 from some of the species involved in the present episode. In total, 11 animals belonging to four different species (banteng, Himalayan tahr, Nile lechwe and sika deer) died between July 2011 and October 2012. The severe gross and histological lesions were consistent with the disease, namely haemorrhages and congestion of several organs as well as lymphoid cell infiltrates and vasculitis of varying severity. The virological tests confirmed that all animals had died of sheep-associated MCF. The investigation indicated that the OvHV-2 infection could have been due to the arrival of sheep in the petting zoo, with cases commencing after first lambing and subsequent shedding of virus. This was also supported by the serological retrospective study that indicated limited previous MCF virus circulation. Further MCF cases that occurred even after the removal of the domestic sheep and goats were attributed to the mouflon. This episode confirms the importance of biosecurity measures in zoos, which house MCF susceptible species, especially those endangered.

Identification of immuno-reactive capsid proteins of malignant catarrhal fever viruses

Malignant catarrhal fever (MCF) is a fatal disease of cattle and other ungulates caused by certain gamma-herpesviruses including alcelaphine herpesvirus-1 (AlHV-1) and ovine herpesvirus-2 (OvHV-2). An attenuated virus vaccine based on AlHV-1 has been shown to induce virus-neutralising antibodies in plasma and nasal secretions of protected cattle but the targets of virus-specific antibodies are unknown. Proteomic analysis and western blotting of virus extracts allowed the identification of eight candidate AlHV-1 virion antigens. Recombinant expression of selected candidates and their OvHV-2 orthologues confirmed that two polypeptides, the products of the ORF17.5 and ORF65 genes, were antigens recognised by antibodies from natural MCF cases or from AlHV-1 vaccinated cattle. These proteins have potential as diagnostic and/or vaccine antigens.

Analysis of the genetic diversity of ovine herpesvirus 2 in samples from livestock with malignant catarrhal fever

In order to define better virus isolates from animals with malignant catarrhal fever (MCF), segments of three genes of ovine herpesvirus-2 were amplified from diagnostic samples representing MCF cases with a range of clinical presentations in cattle, including head and eye, alimentary and neurological. The variation within each gene segment was estimated by DNA sequencing, which confirmed that the newly-annotated Ov9.5 gene was significantly more polymorphic than either of the other loci tested (segments of ORF50 and ORF75), with alleles that differed at over 60% of nucleotide positions. Despite this, the nine Ov9.5 alleles characterised had identical predicted splicing patterns and could be translated into Ov9.5 polypeptides with at least 49% amino acid identity. This multi-locus approach has potential for use in epidemiological studies and in charactering chains of infection. However there was no association between specific variants of OvHV-2 and the clinical/pathological presentation of MCF in the cattle analysed.

Two Different Macaviruses, ovine herpesvirus-2 and caprine herpesvirus-2, Behave Differently in Water Buffaloes than in Cattle or in Their Respective Reservoir Species

The ongoing global spread of “exotic” farm animals, such as water buffaloes, which carry their native sets of viruses, may bear unknown risks for the animals, into whose ecological niches the former are introduced and vice versa. Here, we report on the occurrence of malignant catarrhal fever (MCF) on Swiss farms, where “exotic” water buffaloes were kept together with “native” animals, i.e. cattle, sheep, and goats. In the first farm with 56 water buffaloes, eight cases of MCF due to ovine herpesvirus-2 (OvHV-2) were noted, whereas additional ten water buffaloes were subclinically infected with either OvHV-2 or caprine herpesvirus-2 (CpHV-2). On the second farm, 13 water buffaloes were infected with CpHV-2 and two of those succumbed to MCF. In neither farm, any of the two viruses were detected in cattle, but the Macaviruses were present at high prevalence among their original host species, sheep and goats, respectively. On the third farm, sheep were kept well separated from water buffaloes and OvHV-2 was not transmitted to the buffaloes, despite of high prevalence of the virus among the sheep. Macavirus DNA was frequently detected in the nasal secretions of virus-positive animals and in one instance OvHV-2 was transmitted vertically to an unborn water buffalo calf. Thus, water buffaloes seem to be more susceptible than cattle to infection with either Macavirus; however, MCF did not develop as frequently. Therefore, water buffaloes seem to represent an interesting intermediate-type host for Macaviruses. Consequently, water buffaloes in their native, tropic environments may be vulnerable and endangered to viruses that originate from seemingly healthy, imported sheep and goats.

Malignant Catarrhal Fever: An Emerging Disease in the African Buffalo (Syncerus caffer)

Within the tribe Bovini in the subfamily Bovinae, the water buffalo (Bubalus Bubalis), American bison (Bison bison), European bison (Bubalus bonasus) and yak (Bos grunniens) are recognized as species highly susceptible to malignant catarrhal fever (MCF). In contrast, the lack of reports describing clinical MCF in the African buffalo (Syncerus caffer) whether free ranging or captive has led to a perception that African buffaloes are resistant to MCF. During the last decade, several cases of MCF in African buffaloes were confirmed in South Africa and experience with seven of these cases is described in this report. Detection of viral nucleic acid in blood or tissues was successful in six African buffaloes that suffered from clinical signs compatible with MCF. Four were positive for infection with ovine herpesvirus type 2 (the causative virus of sheep-associated MCF), and two were positive for alcelaphine herpesvirus type 1 (causative virus of wildebeest-associated MCF). Histopathological examination of tissue samples from all the animals yielded typical lesions that were consistent with those described for MCF in domestic cattle. Developments in the management of African buffaloes translocated from their traditional habitats have likely contributed to the identification of another susceptible host in the subfamily Bovinae.

Malignant catarrhal fever in kune kune pigs in the UK

MALIGNANT catarrhal fever (MCF) is an invariably fatal disease of cattle and other ungulates, including pigs, caused by the gammaherpesviruses alcelaphine herpesvirus type 1 and ovine herpesvirus type 2 (OvHV-2)...

Possible natural MCF-like disease in a domestic lamb in Scotland

Malignant catarrhal fever (MCF) is a severe and usually fatal disease of ungulates, including domestic cattle, deer, bison and, occasionally, pigs (Reid and Buxton 1984, Loken and others 1998, Schultheiss...

Experimental induction of malignant catarrhal fever in pigs with ovine herpesvirus 2 by intranasal nebulization

Malignant catarrhal fever (MCF), a frequently fatal herpesviral disease primarily of ruminant species, has been sporadically reported in pigs. All cases of naturally occurring porcine MCF reported to date have been linked to ovine herpesvirus 2 (OvHV-2), a gammaherpesvirus in the genus Macavirus carried by sheep. Experimental induction of MCF by aerosolization of the virus in nasal secretions collected from infected sheep has been successful in bison, cattle and rabbits. The goals of this study were to determine the susceptibility of pigs to MCF following experimental intranasal inoculation of OvHV-2, and to characterize the disease. Twelve pigs in four groups were nebulized with 105, 106, 107, or 108 DNA copies of OvHV-2 from sheep nasal secretions. Three control pigs were nebulized with nasal secretions from uninfected sheep. Three additional pigs were inoculated intravenously with 107 DNA copies of OvHV-2 to evaluate this route of infection with cell-free virus. Seven of twelve intranasally challenged pigs became infected with OvHV-2. Five of these seven, all in higher dose groups, developed MCF. Lesions resembled those reported in natural cases of porcine MCF. The most striking and consistent histological lesions were in trachea, lung, kidney and brain. These comprised mucopurulent tracheitis, interstitial pneumonia, necrotizing arteritis–periarteritis, and nonpurulent meningoencephalitis. No infection was established in the intravenously challenged or control groups. The study showed that MCF can be experimentally induced in pigs by aerosol challenge using sheep nasal secretions containing OvHV-2. Domestic pigs are a natural clinically susceptible host for sheep-associated MCF. They represent a useful, cost-effective model for MCF research.

Malignant catarrhal fever in kune kune pigs in the UK

MALIGNANT catarrhal fever (MCF) is an invariably fatal disease of cattle and other ungulates, including pigs, caused by the gammaherpesviruses alcelaphine herpesvirus type 1 and ovine herpesvirus type 2 (OvHV-2)...

Transmission of Ovine Herpesvirus 2 from Asymptomatic Boars to Sows

To the Editor: Malignant catarrhal fever (MCF) is an often lethal viral disease of susceptible biungulates from the Bovidae, Cervidae, and Suidae subfamilies. MCF in pigs has been associated with direct or indirect contact with sheep, which are the main reservoir of ovine herpesvirus 2 (OvHV-2) (1). A recent report detected infected but asymptomatic swine in the absence of known exposure to sheep or goats (2). Porcine MCF is difficult to diagnose because of its nonspecific clinical signs and sporadic nature; however, an outbreak involving 41 swine has been described (3). Pigs are terminal hosts and are not believed to spread the virus. Here we describe OvHV-2 DNA in the blood and semen of asymptomatic boars and from the brain of symptomatic sows and gilts with MCF that was probably transmitted by artificial insemination. The MCF cases occurred on two 3-site commercial farms with 2,700 and 1,670 sows in 2 different counties in southwestern Brazil. No MCF losses previously had been recorded in the region, and the animals had no known direct or indirect contact with sheep. The 2 farms had high biosecurity. The first case was recorded in September 2004, and the number of cases increased in July 2006. Twenty-eight sows and gilts, 20 of them pregnant and at >25 days’ gestation, died during January 2007–March 2008, when the last case was observed. Clinical features in sows and gilts were depression followed by abortion, fever (41°C), and anorexia. After the onset of clinical signs, neurologic symptoms developed such as ataxia, tremors, convulsions, and aggressive behavior. Animals that survived longer showed forelimb paralysis, stood in a dog-sit position, and gnawed with abundant salivation on pen bars. Specimens from randomly selected dead sows and gilts from the outbreaks during 2004–2008 were obtained for histopathologic examination, immunofluorescence testing for rabies virus, viral and bacterial isolation, and PCR. No bacterial or viral growth was detected, and direct immunofluorescence for rabies virus was negative. Microscopic examination showed high-grade nonpurulent meningoencephalitis characterized by lymphocytic cuffings with vasculitis in the brain hemisphere, the brainstem, the spinal cord, and, to a lesser extent, the cerebellum. Multifocal areas of edema, fibrinoid necrosis, and lymphocytic infiltration also were observed (Figure). OvHV-2 DNA was detected by using a specific PCR (4) in 5 of 7 paraffinized sections of the brainstem (5). To analyze the possible presence of other porcine lymphotropic herpesviruses in samples that reacted positively for OvHV-2, a nested PCR with degenerate primers (6,7) was applied. None of the OvHV-2–positive samples reacted positively for porcine lymphotropic herpesviruses. To confirm that the virus was a member of the MCFV group, we purified 1 amplicon and submitted it for automated sequencing. This nucleotide sequence was deposited in GenBank under accession no. {type:entrez-nucleotide,attrs:{text:HQ223415,term_id:313495121,term_text:HQ223415}}HQ223415, and it showed 99% identity with previously deposited OvHV-2 sequences. Figure Brainstem of a sow with vasculitis that was associated with ovine herpesvirus 2, showing edema, necrosis (fibrinoid necrosis), and infiltration of lymphocytes in the adventitia of the artery. Severe perivascular (Virchow-Robin space) lymphocytic cuffing ... To find possible carriers of the virus, blood samples were collected from 9 pregnant sows, 10 nonpregnant sows, and 30 breeding boars and analyzed for OvHV-2 DNA. Samples from 3 boars were positive. Nasal swabs and semen samples were collected from these infected boars to investigate the potential mode of OvHV-2 transmission, and OvHV-2 DNA was detected only in semen samples. Two of the 3 semen samples had >350 copies/2 µg of total DNA, suggesting that these animals shed virus (8,9). During this period, all infected boars remained clinically healthy. In Brazil, porcine MCF has been found primarily in pregnant sows and gilts. Our findings of OvHV-2 DNA in the semen of asymptomatic boars suggest that the OvHV-2 in the sows and gilts originated from asymptomatic boars that were responsible for maintaining the virus in the herd. Whether virus shedding in the semen was temporary or lasted for a long period is not known. Emergence of OvHV-2 in boars that had no known contact with sheep was surprising, especially given the possibility of venereal transmission through contaminated semen. The occurrence of OvHV-2 infection in other specific pathogen–free farms is unknown, and it is not possible to suggest a strategy to guarantee OvHV-2-free herds.

Outbreak of malignant catarrhal fever among cattle associated with a state livestock exhibition

Severe disease and death were identified in cattle exhibited at a state fair that were naturally infected with ovine herpesvirus type 2 (OvHV-2). Most affected cattle had anorexia, signs of depression, diarrhea, fever, and respiratory distress ultimately leading to death. Mean duration of clinical signs prior to death was 6 days (range, 1 to 26 days). Mean number of days between apparent exposure and death was 71 days (range, 46 to 139 days). 19 of 132 cattle cohoused in 1 barn died of malignant catarrhal fever (MCF). The diagnosis of sheep-associated MCF was confirmed on the basis of results of an OvHV-2-specific PCR assay performed on tissue samples obtained from affected cattle. The disease was associated but not significantly with distance from the center of the barn and was not associated with distance from the center of the sheep pens. Outbreaks of MCF in cattle are unusual, particularly in association with livestock exhibitions. Because the clinical signs may be similar to those of some transboundary diseases, cases of MCF should be reported and investigated. Findings for this outbreak provided evidence to suggest that fair boards and veterinarians should reexamine biosecurity recommendations for livestock exhibitions.