Serological and Molecular Biological Studies of Parvovirus B19, Coxsackie B Viruses, and Adenoviruses as Potential Cardiotropic Viruses in Bulgaria.

Background: Inflammatory diseases of the heart (myocarditis, pericarditis) are commonly caused by viruses. Among the human cardiotropic viruses, parvovirus B19, Coxsackie B viruses, and adenoviruses play a leading role.

Aim: The aim of the present study was to determine the presumptive causative role of parvovirus B19, Coxsackie B viruses, and adenoviruses in the development of myocarditis, pericarditis and dilated cardiomyopathy by demonstrating the presence of specific antiviral antibodies or viral DNA in patients' serum samples.

Materials And Methods: We tested serum samples collected between 2010 and 2014 from 235 patients with myocarditis (n=108), pericarditis (n=79), myopericarditis (n=19), dilated cardiomyopathy (n=7), and fever of unknown origin accompanied by cardiac complaints (n=22). The mean age of patients with the standard deviation was 33 ± 18 years. Serological and molecular methods (ELISA for specific IgM/IgG antibodies to parvovirus B19 and IgM antibodies to Coxsackie B viruses and adenoviruses, and PCR for detection of parvovirus B19 in serum samples, respectively) were used in the study.

Results: Of all tested 235 serum samples, in 60 (25.5%) positive results for at least one of the three tested viruses were detected. Forty out of these 235 serum samples (17%) were Coxsackie B virus IgM positive. They were found in 17% (18/108) of the patients with myocarditis, in 15% (12/79) of those with pericarditis, in 16% (3/19) of those with myopericarditis and in 32% (7/22) in those with fever of unknown origin. The 63 Coxsackie B virus IgM negative patient's serum samples were tested by ELISA for presence of adenovirus IgM antibodies. Such were found in 4 patients with pericarditis and in 2 patients with fever of unknown origin. Every IgM negative sample (n=189) for Coxsackie B and adenovirus was further tested by ELISA for parvovirus B19 IgM/IgG antibodies. B19-IgM antibodies were detected in 14 patients (7.4%). The percentages for B19-IgM antibodies was 8% (7/90), 5% (3/63) and 31% (4/13) in the patients affected with myocarditis, pericarditis, and fever of unknown origin, respectively. Protective B19-IgG antibodies were found in 108 (57%) of the samples. A B19-PCR signal was detected in all the patients who were B19-IgM positive, and in only 1 patient with positive B19-IgG result, the latter presenting with dilated cardiomyopathy.

Conclusion: The present study shows the involvement of Coxsackie B, parvovirus B19 and adenoviruses in the development of inflammatory diseases of the heart (myocarditis and pericarditis). It is the first ever study in the country that simultaneously analyzes the prevalence of the three major human cardiotropic viruses.