Alcelaphine gammaherpesvirus 1-induced malignant catarrhal fever in a Watusi ( Bos taurus africanus) steer in a North American game park.

A 10-y-old Watusi ( Bos taurus africanus) steer housed at a drive-through game park in Winston, Oregon developed severe clinical illness including fever, marked nasal discharge, injected scleral and conjunctival membranes, plus oral hemorrhages and erosions. The animal responded poorly to supportive treatment and was euthanized. Additional gross findings at postmortem examination included papules and erosive lesions on the tongue, hemorrhagic large intestine, and multifocal cardiac hemorrhages. Histopathologic findings included multifocal lymphoplasmacytic vasculitis plus fibrin exudation in heart and tongue. Total DNA obtained from the splenic samples was positive for alcelaphine gammaherpesvirus 1 (AlHV-1) as tested by a multiplex PCR for malignant catarrhal fever (MCF) viruses. The AlHV-1 detection was further confirmed by amplification and sequencing of a viral DNA polymerase gene fragment, which was identical to AlHV-1 sequences in GenBank. This was the first diagnosis of clinical wildebeest-associated MCF on these premises, although wildebeest have been held at the park for over 25 y. This disease is sporadic in North America and should be considered as a differential diagnosis for febrile illness with ulcerative oral lesions in ruminants.

[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.

Effect of interferons on the replication of alcelaphine herpesvirus-1 of malignant catarrhal fever.

Four isolates of alcelaphine herpesvirus-1 of malignant catarrhal fever (MCF) were tested for their inducibility of and sensitivity to various interferons. Viral isolates from an Indian gaur (Bos gaurus), a greater kudu (Tragelaphus strepsiceros) and two wildebeest (Connochaetes gnou) calves did not induce measurable interferon (IFN) in bovine fetal kidney cells. However, these low passages of each virus were all highly cell-associated and viral replication was inhibited at these passages by IFN at 14 IFN units/0.05 ml recovered from NDV-infected MDBK cells and at 7.6 IFN units/0.05 ml of IFN from NDV-infected bovine macrophages. The herpesvirus from the Indian gaur and greater kudu and high passages (greater than 50) of the cell-free WC-11 strain of alcelaphine herpesvirus-1 also were inhibited in their replication by recombinant IFN of bovine and human origins as determined by a fluorescent focus unit (FFU) reduction assay. The concentrations of IFN required to produce a 50% reduction in herpesvirus-produced FFU ranged between 6.4 and 480 IFN units. These findings promote the use of IFN as part of the regimens of treatment of captive endangered ruminant species with clinical MCF.

The clinico-pathology of a malignant catarrhal fever syndrome in the Indonesian swamp buffalo (Bubalus bubalis).

Between September 1979 and May 1982, 50 of 177 swamp buffaloes became sick and died 83 to 719 days (mean 271) after being transferred to a research facility and housed in quarters adjacent to where sheep and goats were kept. The major clinical signs were anorexia, fever, conjunctivitis, scleral hyperaemia, ocular discharge, hyperaemia of skin, enlargement of lymph nodes and depression. Postmortem and histopathological lesions were observed in most of the tissues and organs of the body. A vasculitis with adventitial mononuclear cell infiltration and lymphoreticular reactions suggested a relationship to malignant catarrhal fever. The occurrence of serofibrinous epicarditis and myocarditis, which was seen in buffaloes in all cases, has not been a common finding in ruminants with malignant catarrhal fever.