Profiling cardiovascular viral pathogens in cases of sudden and unexpected death in infants (SUDI) at the Tygerberg Medico-legal Mortuary and the role of myocarditis as a possible cause of death

Venter, Michaela Lucienne (2020-03)

Thesis (MSc)--Stellenbosch University, 2020.

Thesis

ENGLISH ABSTRACT: Introduction: Sudden unexpected death in infancy (SUDI) is a heterogeneous group in which pathological changes, when observed, can either be an adequate or non-conclusive cause of death (COD). A non-conclusive COD is referred to as Sudden Infant Death Syndrome (SIDS), which is postulated to be the result of multiple risk factors including infection. Viral heart infections, resulting in myocarditis, reportedly contribute to SUDI cases. Numerous viruses have been associated with myocarditis, with few ever having been investigated in a South African context. Aim: The study aimed to investigate the presence of three specific viruses in the heart of SUDI cases admitted to the Tygerberg Medico-legal Mortuary over a one-year period. Methodology: Swab samples of the left ventricle of the heart were collected from SUDI cases admitted to the Tygerberg Medico-legal Mortuary over the period of one year. Concurrently, swabs and tissue were retrieved for microbiological and histological analysis, respectively. Conventional qualitative polymerase chain reaction assays were used to detect three deoxyribonucleic acid viruses, namely human adenovirus (HAdV), human bocavirus (HBoV) and parvovirus B19 (PVB19), possibly linked to myocarditis. Clinical history, sociodemographic information and the final COD were collected from case files. All viral results were compared to the histology of the tissue. Associations were investigated between sociodemographic information and viral presence through statistical analysis in order to identify significant risk factors. Results: Heart swabs were collected from 173 SUDI case, consisting of 93 males and 80 females and a mean age of 12.1 ± 9.8 weeks. Over half of the SUDI cases occurred in the cold seasons. The majority of the cases were assigned Infection as a COD, with just under half assigned as SIDS. Only one virus, HBoV, was detected in the heart tissue with implications of myocarditis histologically observed in one of the viral positive SUDI cases. Bacterial presence was also confirmed in only one case. All viral infections were observed in the cold seasons. Risk factors were highlighted between variable associations. Significant associations were observed between prematurity, room ventilation, birthweight and the COD. Significant associations were also observed between microbiology results, histology and the temperature on the day of death. Conclusion: The study expanded the knowledge regarding myocardial infections contributing to SUDI in the study population, as well as significant risk factors. Viral detection in the myocardium, supported by histological evidence, provided an improved way of classifying COD as infection.

AFRIKAANSE OPSOMMING: Agtergrond: Die skielike onverwagte dood in babas, of wiegiedood (SUDI), verwys na alle onverwagte dood in babas waar patologiese veranderinge, as dit waargeneem word, 'n voldoende of onvoldoende oorsaak van dood (OVD) kan bied. Indien daar geen OVD gevind kan word nie, word dit geklasifiseer as “Sudden Infant Death Syndrome” (SIDS). Daar word gepostuleer dat wiegiedood / SUDI plaasvind as gevolg van ‘n oorvleueling van verskeie risikofaktore, insluitend infeksie. Virale hartinfeksies, wat lei tot miokarditis, dra by tot SUDI-gevalle. Talle virusse word met miokarditis geassosieer, maar min daarvan is al in 'n Suid-Afrikaanse konteks ondersoek. Doelstelling: Die doel van hierdie studie was om die teenwoordigheid van drie spesifieke virusse te ondersoek wat in die hart van SUDI-gevalle kan voorkom by die Tygerberg Geregtelik-geneeskundige Lykshuis (GGL) oor 'n tydperk van een jaar. Metodes: Monsters is van die linker hartkamer van alle SUDI-gevalle geneem wat in Tygerberg GGL opgeneem is gedurende Maart 2018 tot Maart 2019. Terselfdertyd is deppers en weefsel vir mikrobiologiese en histologiese ontleding onderskeidelik geneem. Konvensionele kwalitatiewe polimerase-kettingreaksie toetsings is gebruik om drie deoksiribonukleïensuurvirusse (DNS) op te spoor wat tydens miokarditis kan voorkom, naamlik menslike adenovirus (HAdV), menslike bocavirus (HBoV) en parvovirus B19 (PVB19). Kliniese geskiedenis, sosiodemografiese inligting en die finale OVD is ook genoteer. Alle virale resultate is vergelyk met die histologie van die hartweefsel. Assosiasies en verwantskappe tussen sosiodemografiese inligting en die teenwoordigheid van die viruses is deur middel van statistiese ontleding ondersoek om beduidende risikofaktore te identifiseer. Resultate: Hartmonsters is geneem van 173 SUDI-gevalle wat 93 manlike en 80 vroulike babas ingesluit het met ‘n gemiddelde ouderdom van 12.1 ± 9.8 weke. Meer as die helfte van die gevalle het gedurende die koue seisoene voorgekom. ‘n Finale OVD van Infeksie is in die meerderheid van die gevalle bevestig. HBoV was die enigste virus wat in die hartweefsel van ‘n enkele geval opgespoor kon word tydens die studie en hierdie geval het ook histologiese tekens van miokarditis getoon. Bakteriële teenwoordigheid is ook in slegs een geval bevestig. Alle virusinfeksies is gedurende die koue seisoene waargeneem. Beduidende assosiasies tussen prematuriteit, kamerventilasie, geboortegewig en die OVD kon aangetoon word. Verder is assosiasies ook waargeneem tussen mikrobiologiese resultate, histologie en die temperatuur op die dag van die dood. Gevolgtrekking: Die studie het nuwe kennis opgelewer oor miokardiale infeksies, asook beduidende risikofaktore in SUDI. Histologiese tekens van miokarditis, ondersteun deur die teenwoordigheid van virus(se) in die miokardium, kan bydra om die klassifikasie van die OVS as Infeksie te verbeter.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/108273
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