Screening for viruses associated with myocarditis and genotyping human parvovirus B19 in cases of sudden and unexpected death in Infancy (SUDI) at Tygerberg Medico-Legal Mortuary

Date
2023-03
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Stellenbosch : Stellenbosch University
Abstract
ENGLISH SUMMARY: Introduction: The sudden infant death syndrome (SIDS) is one of the primary contributors of infant mortality. The Triple Risk model has identified risk factors that are modifiable and can help in reducing the incidence of SIDS. Sudden unexpected death in infancy (SUDI) is diverse and can be either an appropriate or indeterminate cause of death when pathological changes are observed. Cardiovascular infections are a major contributor to morbidity and mortality in both infants and adults. Aim: The aim of this study was to investigate the presence of specific viruses associated with myocarditis and to genotype Parvovirus B19 in the heart specimens of SUDI cases admitted to the Tygerberg Medico-legal Mortuary. Methodology: Heart samples were collected during the autopsy of the SUDI cases admitted to the Tygerberg Medico-legal Mortuary. Samples for histology and microbiological analysis were also collected. The SUDI samples were further screened for Cytomegalovirus (CMV), Epstein Barr Virus (EBV), Herpes Simplex Virus (HSV) 1 & 2, Human Herpes Virus (HHV) 6 & 7, Varicella-zoster Virus (VZV), Human Adenovirus (HAdV), Human Enteroviruses (HEV), Human parechovirus (HPeV), Mumps virus and Parvovirus B19 (PVB19). Specimens that tested positive for PVB19 were genotyped. Ten residual adult heart specimens positive for PVB19 were also genotyped for comparison. Results: Heart swabs from 40 infants were tested for viruses associated with myocarditis. The study consisted of 18 male and 22 female infants. The mean age of death in weeks was 12.8 weeks. Most deaths occurred during winter (47.5%). More than 50% of infants were sleeping on their side. The following viruses were detected in the infant heart swabs: CMV, EBV, HSV-1, HHV-6, HHV-7, VZV, HAdV, HEV, HPeV and PVB19. All the three PVB19 genotypes were identified, 8 of the adult residual samples were genotype 2 and the other 2 adult specimens were genotype 3 and 1A. The 2 infant samples were both genotype 1A. Conclusion: This study has contributed previously unknown knowledge about myocardial infections and specific PVB19 genotypes found in SUDI cases that could have contributed to myocarditis and sudden death in infants. SUDI research in South Africa is limited and may be of value in the forensic environment when formulating a cause of death in SUDI cases.
AFRIKAANSE OPSOMMING: Inleiding: Die skielike babadoodsindroom, of “wiegiedood” in die volksmond, bly een van die hoofoorsake van babasterftes. Die Drievoudige-Risikomodel het risikofaktore geidentifiseer wat veranderbaar is en kan help om die voorkoms van wiegiedood te verminder. Wiegiedood is uiteenlopend van aard en kan of 'n direkte of indirekte oorsaak van dood wees wanneer patologiese veranderinge waargeneem word. Kardiovaskulêre infeksies lewer ʼn belangrike bydrae tot siekte en dood in beide babas en volwassenes. Doel: Die doel van hierdie studie was om die teenwoordigheid van spesifieke virusse wat met miokarditis geassosieer word te ondersoek en om parvovirus B19 te genotipeer in die hartmonsters van wiegiedood-gevalle wat in die Tygerberg Medies-geregtelike Lykshuis opgeneem is. Metodologie: Hartmonsters is gekollekteer tydens die lykskouing van die wiegiedood gevalle wat in die Tygerberg Medies-geregtelike Lyshuis opgeneem is. Monsters vir histologie en mikrobiologiese analise is ook versamel. Die monsters is verder ondersoek vir die teenwoordigheid van Sitomegalovirus (SMV), Epstein Barr Virus (EBV), Herpes Simpleks Virus (HSV) 1 & 2, Menslike Herpes Virus (MHV) 6 & 7, Varicella-zoster Virus (VZV), Menslike Adenoomvirus (MAdV), Menslike Enterovirusse (MEV), Menslike parechovirus (MPeV), Pampoentjiesvirus en Parvovirus B19 (PVB19). Monsters wat positief getoets het vir PVB19 is genotipeer. Tien volwasse monsters positief vir PVB19 is ook gegentipeer vir vergelyking. Resultate: Hartdeppers van 40 babas is getoets vir virusse wat met miokarditis geassosieer word. Die studie het 18 manlike en 22 vroulike babas ingesluit. Die gemiddelde ouderdom van sterfte in weke was 12.8 weke. Die meeste sterftes het gedurende die winter seisoen voorgekom (47,5%). Die meeste babas het op hul sy geslaap (54.8%). Die volgende virusse is in die babahartdeppers opgespoor: SMV, EBV, HSV-1, MHV6, MHV7, VZV, MAdV, MEV, MPeV en PVB19. Al drie PVB19 genotipes is geidentifiseer, 8 van die volwasse monsters was genotipe 2 en die ander 2 volwasse monsters was onderskeidelik genotipe 3 en 1A. Die 2 babamonsters was albei genotipe 1A. Gevolgtrekking: Hierdie studie het belangrike inligting bygedra tot voorheen onbekende kennis oor miokardiale infeksies en spesifieke PVB19 genotipes gevind in wiegiedood gevalle wat kon bygedra het tot miokarditis en skielike dood by babas. Wiegiedood-navorsing in Suid-Afrika is beperk en kan van waarde wees in die forensiese omgewing wanneer 'n oorsaak van dood in wiegiedood-gevalle geformuleer word.
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Thesis (MSc)--Stellenbosch University, 2023.
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