A comparative study of the pathogenic properties and transmissibility of aGreek and a Belgian encephalomyocarditis virus (EMCV) for piglets

Thirteen susceptible piglets, aged 40 days, were divided into two groups an d were experimentally infected either with a Greek (myocardial) or a Belgia n (reproductive) encephalomyocarditis virus (EMCV) strain (total dose 5 x 1 0(6) TCLD50, intramuscularly and intranasally). Six piglets were placed in the same rooms, 24 h later, as contact controls. The following criteria wer e studied: ante mortem: clinical signs, serum cardiac isoenzyme activities (CR-MB and LD-1), viraemia, nasal and faecal virus excretion and serologica l response. Post mortem (after death or euthanasia): gross lesions, virus i solation from tissues, RT-PCR, as well as histopathological and immunohisto chemical findings. The Greek strain was more pathogenic, producing mortalit y, with high cardiac isoenzyme activities and pronounced macroscopic myocar dium lesions. The Belgian strain was able to induce mild heart lesions, as detected only by cardiac isoenzyme activity and histopathologically. All co ntact pigs were infected, within the first 1-2 days of their introduction, that coincided with the period of viral excretion by the experimentally inf ected pigs (up to the 3rd day post infection). Disease was mild, with no mo rtality. (C) 1999 Elsevier Science B.V. All rights reserved.