In addition to fetal alcohol syndrome and fetal alcohol spectrum disorders, prenatal alcohol exposure is associated with many other adverse pregnancy and birth outcomes. Research suggests that alcohol use during pregnancy may increase the risk of miscarriage, stillbirth, preterm delivery, and sudden infant death syndrome. This research has some inherent difficulties, such as the collection of accurate information about alcohol consumption during pregnancy and controlling for comorbid exposures and conditions. Consequently, attributing poor birth outcomes to prenatal alcohol exposure is a complicated and ongoing task, requiring continued attention to validated methodology and to identifying specific biological mechanisms.

Thesis (MScMedSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Background: Sudden infant death syndrome (SIDS) is considered the second most frequent cause of infant mortality worldwide. Research specifically pertaining to SIDS is limited in the South African setting. Identifiable causes for sudden infant death remain challenging despite full medico-legal investigations inclusive of autopsy, scene visit and ancillary studies. Viral infections could contribute to some sudden unexpected death in infancy (SUDI) cases, especially since a multitude of respiratory viruses have been detected from autopsy specimens. The specific contribution of viruses in the events preceding death, including the subsequent involvement of the immature immune response in infants, still warrants deciphering. Infancy is characterised by marked vulnerability to infections due to immaturities of their immune systems that may only resolve as infants grow older when these sudden deaths rarely still occur. In South Africa there is a lack of a standard protocol for investigations into the causes of SIDS, including the lack of standard guidelines as to which specimens should be taken, which viruses should be investigated and which laboratory assays should be utilised. Objectives: In this prospective descriptive study we aimed to investigate the prevalence of viruses in SUDI and SIDS cases at Tygerberg Forensic Pathology Service (FPS) Mortuary over a one year period. The primary aim was to explore possible respiratory viral infections in SUDI and SIDS cases and to determine the usefulness of molecular techniques to detect viruses from SUDI cases. To determine the significance of viruses, we assessed signs of infection from lung histology. The secondary objectives included collecting demographic data to investigate possible risk factors for SUDI and to look for possible similarities between viruses confirmed in living hospitalised infants at Tygerberg, during the study period compared to viruses detected from SUDI cases. Methods: Between May 2012 and May 2013 samples were collected from 148 SUDI cases presenting at Tygerberg FPS Mortuary. As part of the mandatory routine investigations into SUDI, shell vial culture (SVC) results were collected from lung and liver tissue specimens and bacterial culture results were collected from left and right lung and heart swabs at autopsy. To investigate the possibility of viruses implicated in some of the infant deaths we used the Seeplex® RV15 Ace detection multiplex polymerase chain reaction (PCR) assay to establish the frequency of 13 ribonucleic acid (RNA) respiratory viruses (influenza A and B, human parainfluenza 1-4, human coronavirus [OC43, 229E/NL63], human rhinovirus A, B and C, respiratory syncytial virus A and B, human enterovirus and human metapneumovirus) from RNA extracted from tracheal and lower left and right lung lobe swabs. Tissue from the lower left and right lung lobes were also assessed for histology signs of infection. Results: During our study we confirmed multiple known demographic risk factors for SIDS, such as the age peak around 1-3 months, the male predominance, bed-sharing, sleeping in the prone position, heavy wrapping in warm blankets, prenatal smoke exposure, and socio-economic factors. With the Seeplex® RV15 Ace detection assay between one and three viruses were detected in 59.5% (88/148) of cases. Of the 88 cases that had viruses detected, 75% (66/88) had one virus and 25% (22/88) had co-detections of two to three viruses. The most common viruses detected were HRV in 77% (68/88) of cases, RSV in 18% (16/88) of cases and HCoV in 14% (12/88) of cases. Many of the viruses we detected from our cases are included in the SVC test that forms part of the medico-legal laboratory investigation for all SUDI cases at Tygerberg FPS Mortuary. SVCs were positive in 9.5% (14/148) of all cases only. We showed that the SVC method is potentially missing most of the 13 respiratory viruses we investigated that could contribute to death in some of the SUDI cases. Conclusion: In some cases that had a Cause of Death Classification - SIDS, the PCR viruses detected cannot be ignored, especially when it is supported by histological evidence of infection. We thus propose that the use of PCR could alter a Cause of Death Classification from SIDS to Infection in some of these cases. Further research is needed to determine the significance of detecting viruses from SUDI cases wherein no significant histological evidence of infection was observed. This questions whether PCR may be too sensitive and is detecting past and latent viral infections that do not play any role in the cause of death. The histological picture also requires further characterisation to determine if it accurately predicts infections or lethal events and can truly support virology findings, especially in young infants whose immune systems are still maturing. Without determining the true prevalence of viruses in SUDI cases and the viral-specific immune response, the contribution of virus-specific infections to this syndrome will remain largely undetermined. / AFRIKAANSE OPSOMMING: Agtergrond: Wiegiedood (“SIDS/SUDI”) word beskou as die tweede mees algemene oorsaak van sterftes in kinders jonger as een jaar wêreldwyd. Toegewyde SIDS-spesifieke navorsing in die Suid-Afrikaanse samelewing is beperk. Dit bly steeds „n uitdaging om oorsake te probeer identifiseer vir hierdie onverwagte sterftes in kinders (SUDI) ten spyte van volledige medies-geregtelike ondersoeke, insluitende die lykskouing, ondersoek van die doodstoneel en aanvullende ondersoeke. Virusinfeksies kan aansienlik bydra tot sommige onverwagte sterftes in kinders, aangesien verskeie respiratoriese virusse alreeds aangetoon is in monsters verkry tydens outopsies. Die spesifieke rol wat virusse speel in die prosesse wat die dood voorafgaan, asook die bydraende rol van „n onder-ontwikkelde immuunrespons in babas, regverdig verdere ondersoek. Die eerste jaar van lewe word gekenmerk deur verhoogde vatbaarheid vir infeksies weens die ontwikkelende immuunstelsels soos wat babas ouer word, en die voorkoms van SUDI neem stelselmatig af met „n toename in ouderdom. In Suid-Afrika bestaan daar tans geen standaard protokol vir die ondersoek van wiegiedood nie en daar is ook nie standaard riglyne oor die tipe monsters wat geneem moet word, watter virusse ondersoek moet word en watter laboratorium toetse uitgevoer moet word nie. Doelstellings: In hierdie prospektiewe beskrywende studie is gepoog om die virusse wat in gevalle van wiegiedood of SUDI voorkom te ondersoek. Die studie is uitgevoer by die Tygerberg Geregtelike Patologie Dienste lykshuis oor 'n tydperk van een jaar. Molekulêre tegnieke om virusse aan te toon in hierdie gevalle is gebruik om spesifieke virusinfeksies te ondersoek. Die resultate is met histologiese tekens van infeksie in longweefsel gekorreleer. Demografiese data is verder versamel om moontlike risikofaktore vir wiegiedood te ondersoek. Dit is verder vergelyk met virusse wat met dieselfde diagnostiese tegnieke in babas geïdentifiseer is wat tydens die studieperiode in Tygerberg Hospitaal opgeneem was met lugweginfeksies. Metodes: Monsters van 148 SUDI gevalle wat by die Tygerberg lykshuis opgeneem is, is versamel tussen Mei 2012 en Mei 2013. As deel van die roetine ondersoeke in SUDI gevalle, was selkultuur resultate verkry van long en lewer weefsel, asook bakteriële kulture van deppers wat van beide longe en hart geneem was tydens die lykskouings. „n Seeplex® RV15 Ace polimerase kettingreaksie (PKR) toets is gebruik om die teenwoordigheid van virusse te ondersoek wat moontlik by die babasterftes betrokke kon wees. Trageale- en longdeppers wat tydens die lykskouings versamel was, was getoets vir 13 ribonukleïensure (RNS) respiratoriese virusse (influenza A and B, human parainfluenza 1-4, human coronavirus [OC43, 229E/NL63], human rhinovirus A, B and C, respiratory syncytial virus A and B, human enterovirus and human metapneumovirus). Resultate: Ons studie het verskeie bekende demografiese risikofaktore vir SUDI bevestig, byvoorbeeld „n ouderdomspiek tussen een en drie maande ouderdom, manlike predominansie, deel van „n bed met ander persone, slaap posisie op die maag, styf toedraai in warm komberse, blootstelling aan sigaretrook voor geboorte en sosio-ekonomiese faktore. Die Seeplex® RV15 Ace toets het tussen een en drie virusse geïdentifiseer in 59.5% (88/148) van die gevalle. Uit die 88 gevalle waarin virusse opgespoor was, was selgs een virus in 75% (66/88) van gevalle gevind en twee en drie virusse in 25% (22/88). Die mees algemene virusse was HRV in 77% (68/88) van gevalle, RSV in 18% (16/88) van gevalle en HCoV in 14% (12/88) van gevalle. Baie van die virusse wat tydens hierdie studie ondersoek was, was ingesluit in die roetine selkultuur toets wat deel vorm van die standaard medies-geregtelike laboratoriumondersoeke in alle SUDI gevalle by die Tygerberg lykshuis, alhoewel die selkulture positief was in slegs 9.5% (14/148) van gevalle. Ons het gevind dat baie respiratoriese virusse potensieel gemisdiagnoseer word wat „n rol kon speel in of bydra tot die dood van sommige SUDI gevalle. Gevolgtrekking: In sommige gevalle waarin SIDS geklassifiseer is as die oorsaak van dood, kan die virusse wat met PKR toetse opgespoor is nie geïgnoreer word nie, veral waar die bevinding ondersteun word deur histologiese bewyse van infeksie. Ons stel dus voor dat die gebruik van PKR toetse die oorsaak van dood klassifikasie kan verander van SIDS na Infeksie in sommige van hierdie gevalle. Verdere navorsing is nodig om die waarde van gelyktydige opsporing van virusse in SUDI gevalle te bepaal wanneer daar geen noemenswaardige histologiese bewyse van infeksie gevind word nie. Dit bevraagteken of die PKR toets dalk te sensitief is en gevolglik vorige en latente virusinfeksies identifiseer wat nie noodwendig 'n rol in die oorsaak van dood speel nie. Die diagnostiese en kliniese waarde van die histologiese beeld in terme van die rol van virusinfeksies as bydraende oorsaak van dood moet verder ondersoek word, veral in jong kinders wie se immuunstelsels nog nie volledig ontwikkel is nie. Indien die werklike voorkoms van virusse in SUDI gevalle en die virus-spesifieke immuunrespons nie bepaal word nie, sal die rol van virus-spesifieke infeksies in hierdie sindroom grootliks onbekend bly. / Harry Crossley Foundation / Poliomyelitis Research Foundation (PRF) / National Health Laboratory Services Research Trust

Der plötzliche Kindstod (engl. Sudden Infant Death Syndrome-SIDS) ist die häufigste Todesursache bei Säuglingen innerhalb des ersten Lebensjahres. Die zugrundeliegenden pathophysiologischen Veränderungen sowie die genaue Todesursache sind bis dato ungeklärt. Viele Forschungsbereiche setzen sich intensiv mit der Klärung dieses „Phänomens“ auseinander. Ein Schwerpunkt liegt auf dem genetischen Gebiet und der Betrachtung verschiedener Polymorphismen. Ein Fokus wird hierbei auf die genetischen Polymorphismen der mitochondrialen DNA (mtDNA) gesetzt. In der vorliegenden Arbeit wurden daher drei Polymorphismen der mtDNA und mögliche Risikofaktoren im Bezug zu SIDS-Fällen untersucht. Die Folge eines mitochondrialen Polymorphismus kann beispielsweise die verminderte Genexpression der Untereinheiten der Atmungskette zur Folge haben. Daraus kann ein Defizit in der ATP (Adenosintriphosphat)-Produktion resultieren. Der physiologische Kreislauf einer menschlichen Zelle ist durch dieses Defizit nur eingeschränkt gewährleistet. Im Rahmen der Forschungsarbeit wurden die SNPs G3010A, T16519C und C7028T der mtDNA in Hinblick auf einen möglichen Zusammenhang mit dem SIDS untersucht. Schon 2003 untersuchten Divne et al. (2003) einen möglichen Zusammenhang der SNPs G3010A und C7028T im Zusammenhang mit SIDS, jedoch ohne signifikantes Ergebnis. Boles et al. (2010) konnten eine Assoziation zwischen den Polymorphismen G3010A und T16519C mit dem plötzlichen Kindstod herstellen. Da bislang jedoch keine ausführliche Publikation zu dieser Frage vorliegt, wurde mit der vorliegenden Arbeit die Rolle der Polymorphismen G3010A und T16519C in Bezug auf den plötzlichen Kindstod gemeinsam mit der (bei Europäern) häufigsten Variation C7028T untersucht. Die DNA von 176 SIDS-Fällen und einer Kontrollgruppe von 113 Erwachsenen wurde mittels Singleplex-PCR und RFLP-Analyse genotypisiert. Anhand der Genotypisierung konnten die SNPs quantifiziert und im Hinblick auf einen möglichen Unterschied zwischen SIDS-Fällen und der Kontrollgruppe untersucht werden. Bei Betrachtung der einzelnen SNPs G3010A, T16519C und C7028T lassen sich keine signifikanten Unterschiede zwischen den SIDS-Fällen und der Kontrollgruppe feststellen. Das gehäufte Vorliegen einer erhöhten Mutationsrate in einem Individuum bei SIDS-Fällen im Vergleich zur Kontrollgruppe, sowie die von Opdal et al. (1999) geäußerte Annahme, dass beim Vorliegen einer Mutation in der D-Loop-Region weitere Mutationen im kodierenden Bereich vorkommen, konnten durch diese Arbeit bestätigt werden.