CIRCOVIRUS-MYCOPLASMA INFECTION OF PIGLETS IN THE EXPERIMENT

Abstract

The aim of the study is to investigate the manifestation of circovirus-mycoplasma infection in piglets both as a mixed infection and as a monoinfection in the experiment. Objectives: to study the interaction of circovirus type 2 with Mycoplasma hyopneumoniae in the body of weaned piglets, as well as the manifestation of monoinfection in piglets during experimental infection; to assess the pathogenicity of PCV2d/M.hyo mixed infection, PCV2d monoinfection and M. hyo monoinfection; to identify the clinical and pathomorphological manifestation of mixed and single circovirus and mycoplasma infection in the experiment. Four groups of 23-day-old piglets (5 heads each) were formed and tested for the absence of pathogens. Experimental group I – mixed circovirus-mycoplasma infection, experimental group II – PCV2d monoinfection, experimental group III – M.hyo monoinfection, group IV – control. After infection, rectal temperature was measured daily and clinical manifestations were observed, nasal swabs were taken to determine the number of copies of M. hyo nucleic acid, blood was taken from each piglet weekly to detect viral nucleic acid and antibodies. All experimental and control piglets were euthanized on the 35th day from the beginning of the experiment. Pathomorphological and pathohistological studies were carried out. The experimental study reveals the synergistic pathogenicity of PCV2d and M. hyo in mixed infection. In experimental infection of weaning piglets with both M. hyo monoinfection and M. hyo/PCV2d mixed infection, it was found that M. hyo nucleic acid was detected in nasal smears in 80 % of animals and in lung tissue in 100 %. The number of copies of the PCV2d circovirus genome in the inguinal lymph node tissue of piglets in the mixed infection group was higher than in the monoinfection group. Circovirus type 2 in piglets can proceed latently, and circovirus-mycoplasma infection can be a complex respiratory disease.