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.

Bovine malignant catarrhal fever: case reporting in Central Italy.

A case of malignant catarrhal fever (MCF) occurred in a 4­month­old calf housed in a semi­intensive herd in central Italy is described. The herd was in strict cohabitation with a group of domestic sheep. The calf displayed clinical signs that resembled the acute form of MCF and, after a few days of antibiotic and anti inflammatory therapy, died in September 2016. The diagnosis was confirmed in vivo in blood by detection of ovine herpesvirus type 2 DNA through real­time PCR. At necropsy, the gross post­mortem findings were typical of MCF and the histological and molecular assays confirmed the presence of the virus. The sheep flock was suspected to be the source of the infection. In Italy, as well as in Europe, there is little data regarding the epidemiology and the recurrence of the disease in herds of cattle, due to the lack of an active surveillance plan and to a major consideration of MCF between differential diagnosis.

[Interleukin-2 for the treatment of cows with malignant catarrhal fever]. / Behandlung von Rindern mit Bösartigem Katarrhalfieber mit Interleukin-2.

The goal of this study was to investigate whether administration of interleukin-2 (IL-2) would improve the outcome of cows with malignant catarrhal fever (MCF). The study population consisted of ten healthy control cows and 22 cows with MCF. Nineteen cows with MCF and all of the controls were treated with either 2'500 U IL-2 or 25'000 U IL-2, administered intravenously. Three cows with MCF were not treated with IL-2 (MCF controls). All of the cows with MCF received danofloxacin, flunixin meglumine and intravenous fluid therapy. Blood samples for haematological and biochemical evaluation were collected once daily for six days in all cows. Of the 19 cows treated with IL-2, 13 were eutha nized because of deterioration. All cows with MCF that did not receive IL-2 died. The clinical condition of six cows treated with 2'500 U IL-2 gradually improved. Sur viving cows had significantly higher total leukocyte counts than cows that died or were euthanized. The main reason for leukopenia in non-surviving vs. surviv ing cows was persistent lymphopenia. Use of the lower IL-2 dose was associated with clinical recovery in some cows and this treatment might therefore be considered in valuable cows, provided that the lymphocyte count is within the reference interval.

Vitamin D status in cattle with malignant catarrhal fever.

The aim of the present study was to determine the vitamin D status in cattle with malignant catarrhal fever (MCF). Twelve cattle diagnosed as MCF and 6 healthy cattle (controls) were used in the study. Serum 1,25-dihydroxyvitamin D(3) (1,25-D), 25-hydroxyvitamin D(3) (25-D), calcium, phosphorus and parathyroid hormone (PTH) levels were determined as 96.83 pg/ml, 30.0 ng/ml, 2.19 mmol/l, 1.57 mmol/l and 15.21 pg/ml in MCF group and 42.33 pg/ml, 37.0 ng/ml, 2.43 mmol/l, 1.96 mmol/l and 36.08 pg/ml in controls, respectively. Although serum 1,25-D level in the MCF group was increased (P<0.01), serum calcium (P<0.01) and PTH (P<0.05) levels were decreased compared to the controls. The results suggest that there might be an interaction between vitamin D status and MCF.

Development of an enzyme-linked immunosorbent assay for the detection of antibodies against malignant catarrhal fever viruses in cattle serum.

Malignant catarrhal fever (MCF) is a sporadic but fatal lymphoproliferative viral disease of cattle, deer and other ruminants. The causative agents are highly-cell-associated herpesviruses of the subfamily gammaherpesvirinae. In this study, an ELISA (WC11-ELISA) was developed to detect antibody to malignant catarrhal fever virus (MCFV) in cattle serum and compared to the commercially produced competitive-inhibition ELISA (CI-ELISA). Crude lysate antigen from alcelaphine herpesvirus-1 strain WC11 was bound to 96-well microplates and used to capture antibodies to MCFV. Dilutions of test sera were added to wells containing bound MCF antigen and control wells containing uninfected cell lysates. A horseradish peroxidase-labelled rabbit-anti-bovine IgG conjugate detected antibodies to MCF, and the results were expressed as absorbance readings at 450 nm. Samples were selected blind from cattle sera which had been sent to the laboratory for diagnostic testing for MCFV antibodies and were tested in both the WC11-ELISA and the CI-ELISA. Good agreement between the WC11-ELISA and CI-ELISA test (k=0.86, n=95) results was found.

Sequence variation at a Bmy I/Rsa I restriction site in ovine herpes virus 2.

DNA samples extracted from a bovine brain, one blood and one buffy coat sample from three cattle with malignant catarrhal fever, and from 47 samples of pooled sheep sera, were amplified by nested polymerase chain reaction (PCR) using primers specific for ovine herpes virus 2 (OHV-2). Confirmation of the specificity of the amplified DNA segment by restriction enzyme analysis with Rsa I and Bmy I as described by Baxter et al. was obtained in most samples. Nine amplified DNA samples could not be digested, or were only partially cut, with these enzymes. Sequencing of six samples revealed a two-nucleotide substitution in the middle of the restriction site (AA vs. CG) in four of these samples (the bovine brain and three sera), and two peaks at each of these positions (C or A, G or A) in two samples from pooled ovine serum. These results indicate the existence of a variant of OHV-2, and that both the previously sequenced OHV-2 and the variant were present in some samples of pooled ovine serum.

Evidence of persistent malignant catarrhal fever infection in a cow obtained by nucleic acid hybridisation.

A natural non-fatal case of sheep-associated malignant catarrhal fever in a cow is reported. Viral DNA confirmed by nucleic acid hybridisation and polymerase chain reaction persisted in peripheral blood leukocytes for at least 3 months after the clinical onset of the disease. Concultivation of leukocytes with various cell cultures failed to result in isolation of the virus either by cytopathic effect or by nucleic acid hybridisation.

Fatal respiratory disease in Nilgiri tahr: possibly malignant catarrhal fever.

Nilgiri tahr (Hemitragus hylocrius) are native to India and are a rare zoo exhibit. This report describes an acute respiratory disease in tahr that caused the death of 15 of 16 animals in an extensive exhibit of about 35 acres where they were housed together with a variety of other exotic species of ruminants. The deaths occurred in two separate outbreaks and were associated with losses from malignant catarrhal fever in other ruminants in the exhibit. The most prominent clinical sign was severe dyspnea, and death occurred within five days. The principal lesions were an acute nonsuppurative inflammation of the respiratory tract and pulmonary vessels, lymphadenopathy and lymphoid cell infiltration in the organs of some animals. It was conjectured that the tahr died of a unique pneumonic form of malignant catarrhal fever. Attempts at viral isolation were negative.

The pathology of "sheep-associated" malignant catarrhal fever in the hamster.

Lesions induced in hamsters by inoculation with the "sheep-associated" agents of malignant catarrhal fever (SA-MCF) isolated from a red deer (Cervus elaphus), designated D/1 and of bovine origin (C/2), are described. Clinical signs in hamsters inoculated with the D/1 isolate occurred as early as 13 days after infection although the mean incubation period in animals that developed signs was 27 days. Increased numbers of polymorphonuclear leucocytes were present in the blood of clinically affected hamsters. Gross lesions included erosions of epithelium in the buccal cavity, haemorrhage of the forestomach, dilated fluid-filled intestines and enlargement of the mesenteric lymph node. Microscopic lesions were widespread throughout the body but had a predilection for epithelial surfaces. They consisted of hyperplasia of certain lymph nodes, vasculitis and interstitial accumulations of mononuclear cells of lymphoid appearance in non-lymphoid tissues. Cytolysis was also seen. Lesions produced by the C/2 isolate were similar and both isolates produced disease comparable with that seen in naturally occurring cases in cattle and deer. It is suggested that disease might arise through a dysfunction of the immune system following infection of host large granular lymphocytes by the SA-MCF agent, in a way similar to that suggested for the rabbit.