Current SIDS research: time to resolve conflicting research hypotheses and collaborate

From the earliest publications on cot death or sudden infant death syndrome (SIDS) through to this day, clinical pathology and epidemiology have strongly featured infection as a constant association. Despite mounting evidence of the role of viruses and common toxigenic bacteria in the pathogenesis of SIDS, a growing school of thought featuring a paradigm based on the triple risk hypothesis that encompasses vulnerability through deranged homoeostatic control of arousal and/or cardiorespiratory function has become the mainstream view and now dominates SIDS research. The mainstream hypothesis rarely acknowledges the role of infection despite its notional potential role as a cofactor in the triple hit idea. Decades of mainstream research that has focussed on central nervous system homoeostatic mechanisms of arousal, cardiorespiratory control and abnormal neurotransmission has not been able to provide consistent answers to the SIDS enigma. This paper examines the disparity between these two schools of thought and calls for a collaborative approach. IMPACT: The popular research hypothesis explaining sudden infant death syndrome features the triple risk hypothesis with central nervous system homoeostatic mechanisms controlling arousal and cardiorespiratory function. Intense investigation has not yielded convincing results. There is a necessity to consider other plausible hypotheses (e.g., common bacterial toxin hypothesis). The review scrutinises the triple risk hypothesis and CNS control of cardiorespiratory function and arousal and reveals its flaws. Infection-based hypotheses with their strong SIDS risk factor associations are reviewed in a new context.

A mouse zoonotic virus (LCMV): A possible candidate in the causation of SIDS

Lymphocytic choriomeningitis virus (LCMV) is a ubiquitous virus carried by rodents. It causes human disease through contact with infectious mouse faeces, urine or secretions. The virus initially infects the human respiratory tract and lungs and produces typical viral symptoms and signs. The infection is usually self-limiting and recovery is the norm. A small proportion of individuals may develop aseptic meningitis. It is hypothesised that in infancy the virus may cause respiratory tract infection through contact with mouse excreta. The infection could activate production of staphylococcal enterotoxin in babies who are colonised by Staphylococcus aureus. Indeed, a mouse animal model has shown that the combination of LCMV infection and introduction of enterotoxin B produces fatal haematogenous shock. Neither agent alone is lethal. Pathological (and physiological) evidence indicates shock could be the underlying terminal event in SIDS (the observed tissue damage seen in the heart and diaphragmatic muscles, and apoptosis observed in the brain and brainstem of SIDS cases). These features are consistent with a haematogenous shock event. The epidemiology of SIDS is entirely consistent with a mouse-related viral zoonosis. Moreover, rural cases of SIDS tend to feature more often than urban cases and their occurrence would be consistent with the dynamics of mouse populations. Low socioeconomic living conditions (a major risk factor for SIDS) is consistent with prevalence of mouse populations and poor hygienic conditions, with overcrowding. Prone sleeping would facilitate aspiration or ingestion of infectious material from contaminated surfaces. and poor hygienic conditions, with overcrowding, and prone sleeping would facilitate aspiration or ingestion of infectious material from contaminated surfaces. The epidemiology and pathology of SIDS and the dynamics and ubiquity of mouse populations together with human serological data would support the hypothesis that LCMV is a potential candidate as a key factor in the causation of SIDS.

Infection, Celestial Influences, and Sudden Infant Death Syndrome: A New Paradigm

The etiology of sudden infant death syndrome (SIDS) still remains unclear. This situation would seem unprecedented for 21st-century medical science. This article explores scientific fields that have not been largely considered in investigating the etiology of SIDS so far. In this study, we examined previously ignored studies on heliobiology, celestial influences, and SIDS in the non-medical literature in an attempt to answer the following questions: is there a relationship between sunspot/solar activity and the occurrence of SIDS? Could there be alternative reasons for the decline in SIDS incidences in the 1990s that were originally attributed to the “Back-to-Sleep” campaign? We note that the decline coincided with the ~11-year cyclical diminution in sunspot numbers (SSNs). The SSN/SIDS relationship does not necessarily imply causality; however, it supports published data regarding sunspots, Schumann resonance, and geomagnetic effects. How solar energy could adversely influence a baby’s existence remains conjectural. Observations in this respect suggest pathways involving melatonin and/or infection/inflammation.

SIDS, prone sleep position and infection: An overlooked epidemiological link in current SIDS research? Key evidence for the "Infection Hypothesis"

Mainstream researchers explain the etiology of SIDS with the cardiorespiratory paradigm. This has been the focus of intense study for many decades without providing consistent supporting data to link CNS findings to epidemiological risk factors or to the usual clinicopathological findings. Despite this, and the apparent oversight of the link between prone sleep position and respiratory infection, papers citing CNS, cardiac and sleep arousal findings continue to be published. Discovery of the prone sleep position risk factor provided tangential support for the cardiorespiratory control hypothesis which defines the mainstream approach. Despite many decades of research and huge expenditure, no aetiological answer has been forthcoming. In asking why?This paper exposes some of the shortcomings regarding this apparent oversight by mainstream SIDS researchers and examines the role of respiratory infection and puts the case for the “Infection Hypothesis.” In addition, the paper provides encouragement to neuropathologists to examine the potential link between CNS findings and cardiac function (as opposed to respiratory function) in relation to infection and to examine possible correlates between CNS findings and established risk factors such as recent infection, contaminated sleeping surfaces, maternal/obstetric/higher birth, ethnicity, non-breast-feeding, male gender, etc. or with the usual gross pathological findings of SIDS (intrathoracic petechial hemorrhages, liquid blood, congested lungs). The shortcomings exposed through this review invite questions over current research directions and hopefully encourage research into other more plausible hypotheses, such as the infection paradigm.•

Mainstream SIDS researchers appear to have overlooked the key relationship between prone sleep position and infection.

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This omission has major implications for current and future SIDS research.

Intestinal Microbiota Composition in Sudden Infant Death Syndrome and Age-Matched Controls

OBJECTIVE

To assess whether features of the infant intestinal microbiome, including the carriage of toxigenic bacteria, are associated with sudden infant death syndrome (SIDS).

STUDY DESIGN

We undertook a case-controlled analysis of fecal microbiology in SIDS. Fecal material was obtained from 44 cases and 44 aged-matched controls. Microbiota composition was determined by 16S ribosomal RNA gene amplicon sequencing and comparisons between cases and controls made based on both bacterial alpha diversity measures and unconstrained ordination. Specific quantitative polymerase chain reaction assays were used to determine intestinal carriage of Staphylococcus aureus, toxigenic Clostridium difficile, and pathogenic and nonpathogenic Escherichia coli.

RESULTS

The microbial composition for the study population as a whole was consistent with previous studies of infants <12 months of age, with a correlation between alpha diversity and age (r² = 0.08; P = .007). However, no difference was observed in alpha diversity between SIDS cases and controls (P > .4). Nonmetric multidimensional scaling also revealed no evidence of differences in microbiota dispersal between SIDS cases and controls (P = .4, permutational multivariate ANOVA test; Pseudo-F = 0.9), nor was a difference observed in microbiota dispersion (P = .19, PERMDISP test; F = 1.9). There were no significant intergroup differences in the carriage of S aureus, toxigenic C difficile, total E coli, or pathogenic E coli.

CONCLUSIONS

We found no evidence of an association between altered intestinal microbiology and SIDS, or to support the development of strategies to reduce the incidence of SIDS that target intestinal microbiology.

A Survey of Nosocomial Respiratory Viral Infections in a Children's Hospital: Occult Respiratory Infection in Patients Admitted During an Epidemic Season

Objective:

To define the extent of shedding of respiratory viruses and Mycoplasma pneumoniae among a population of pediatric patients admitted to the hospital during a winter epidemic period and to identify nosocomial infections within this population.

Design:

An open, prospective survey of patients admitted to three wards (General Medical, Respiratory Infectious, and Infectious Diseases) of a pediatric hospital during a defined three-month period.

Patients:

All patients with medical, respiratory, and infectious conditions admitted to three wards of the Adelaide Children's Hospital had nasopharyngeal aspirations performed at the time of admission with the purpose of documenting viral and M pneumoniae shedding. Patients were monitored daily for the development of symptoms of respiratory infection or new symptoms of respiratory disease. Such patients underwent a further nasopharyngeal aspiration for the purpose of diagnosing hospital-acquired infection.

Results:

Nasopharyngeal aspirations were obtained from 601 patients. Forty-seven percent of asymptomatic patients were positive for a respiratory virus or M pneumoniae, and 61% of patients with respiratory symptoms were also positive. Gastroenteritis patients shed viruses in 66% of cases. Respiratory symptoms were initially overlooked by admitting physicians but subsequently identified in 110 cases, and 46% of these were found to be positive for a respiratory virus or M pneumoniae. There were 18 possible hospital acquired infections among the 293 initially virus-negative patients. Multiple isolates were obtained from a substantial number of patients, especially those with respiratory symptoms.

Conclusions:

A substantial proportion of all patients admitted to a pediatric hospital during winter represent a potential source of infection, and strict infection control measures should be enacted to limit the spread of these infections.

Escherichia coli and Sudden Infant Death Syndrome

This review examines the association of strains of Escherichia coli with sudden infant death syndrome (SIDS) and the possible role these bacteria play in this enigmatic condition. The review addresses evidence for E. coli in SIDS infants, potential sources of E. coli in the environment, colonization by commensal and pathogenic strains, the variety of currently accepted pathotypes, and how these pathotypes could compromise intestinal integrity and induce inflammation. Both intestinal and extraintestinal pathotypes are compared in relation to the apparent liability in which virulence traits can be gained or lost by strains of E. coli. The way in which E. coli infections fit with current views on infant sleeping position and other SIDS risk factors is highlighted.

Gut Microbiota and Immunity: Possible Role in Sudden Infant Death Syndrome

The gut microbiome influences the development of the immune system of young mammals; the establishment of a normal gut microbiome is thought to be important for the health of the infant during its early development. As the role of bacteria in the causation of sudden infant death syndrome (SIDS) is backed by strong evidence, the balance between host immunity and potential bacterial pathogens is likely to be pivotal. Bacterial colonization of the infant colon is influenced by age, mode of delivery, diet, environment, and antibiotic exposure. The gut microbiome influences several systems including gut integrity and development of the immune system; therefore, gut microflora could be important in protection against bacteria and/or their toxins identified in SIDS infants. The aims of the review are to explore (1) the role of the gut microbiome in relation to the developmentally critical period in which most SIDS cases occur; (2) the mechanisms by which the gut microbiome might induce inflammation resulting in transit of bacteria from the lumen into the bloodstream; and (3) assessment of the clinical, physiological, pathological, and microbiological evidence for bacteremia leading to the final events in SIDS pathogenesis.

Gut microbiome in sudden infant death syndrome (SIDS) differs from that in healthy comparison babies and offers an explanation for the risk factor of prone position

The role of bacteria in the causation of sudden infant death syndrome (SIDS) is gaining acceptance. Mainstream research favouring respiratory compromise has failed to provide a plausible pathogenetic mechanism despite many years of investigation and thousands of research papers. Bacterial colonisation of the colon of the human infant is influenced by many factors including age, mode of delivery, diet, environment, and antibiotic exposure. The gut microbiome influences development of the immune system. The gut microflora could be important in protection against the bacteria and/or their toxins purportedly involved in SIDS pathogenesis. The aim was to perform a preliminary investigation of the gut microflora in sudden infant death syndrome (SIDS) compared with live comparison babies. The intestinal contents from 52 SIDS, and 102 faecal samples from age-matched live comparison infants were screened by PCR to target 16s RNA genes of Clostridium innocuum, Cl. Perfringens, Cl. difficile, Bacteroides thetaiotaomicron and Staphylococcus aureus. Gut colonisation of the babies with these bacteria was analysed in relation to age, gender and type of feeding; and for SIDS babies sleeping position. Cl. difficile, Cl. innocuum and B. thetaiotaomicron were significantly associated with SIDS with 25%, 46% and 30% of cases PCR positive for these respective bacteria compared with only 6%, 23% and 8.8% respectively in the comparison group. SIDS babies had dual colonisation by both Cl. perfringens and Cl. difficile significantly more often than comparison babies and also with triple colonisation by Cl. perfringens, Cl. difficile and Cl. innocuum. SIDS babies were more often colonised by S. aureus than comparison babies. In addition, SIDS babies found prone were significantly more likely to be colonised by S. aureus than for other positions recorded (OR = ∞; CI = 2·04 - ∞). No significant differences between breast and bottle-fed SIDS babies was observed in regard to each clostridial bacterium, or S. aureus, however Cl. innocuum was found to be significantly associated with formula feeding in the comparison cohort. Comparison of breast and formula feeding of SIDS babies with live comparison babies revealed significant differences with regards to some of the clostridial bacteria. Age-specific differences in gut bacterial microbiome were observed in both SIDS and comparison healthy babies. This study gives an insight into differences in the gut bacterial microbiome of SIDS babies compared with healthy babies. These differences could be important in contributing to a baby's susceptibility to infection and therefore to SIDS. The association of S. aureus colonisation with prone sleep position supports the hypothesis that prone sleep position could increase the risk of ingestion/inhalation of bacteria contaminating the sleeping surface and could account for the increased risk of SIDS in babies who are put to sleep prone. The study provides impetus for broader studies into the gut microbiome of babies and could lead to effective approaches to SIDS prevention.

Treatment and prevention of enterohemorrhagicEscherichia coliinfection and hemolytic uremic syndrome

Over a quarter century after the discovery of verocytotoxin and the first report by Karmali and colleagues of cases of postdiarrheal hemolytic uremic syndrome (HUS) caused by verotoxigenic Escherichia coli (VTEC), otherwise known as Shiga-toxigenic E. coli (STEC), successful treatment of these infections has remained elusive. This is because the pathological insult producing the clinical picture of HUS occurs early in the disease process and curtails quickly, making treatment intervention a largely vain hope. Nevertheless, understanding of the pathogenesis of HUS has expanded and, as a result, we can expect a future breakthrough in the treatment of this life-threatening condition. This review examines the pathogenesis of HUS and explores targets for treatment, including the reasons why certain therapies have failed and why future therapies could be successful. This review also examines the status of vaccine development in prevention of VTEC/STEC disease.

Iatrogenic blood-borne viral infections in refugee children from war and transition zones

Pediatric infectious disease clinicians in industrialized countries may encounter iatrogenically transmitted HIV, hepatitis B virus, and hepatitis C virus infections in refugee children from Central Asia, Southeast Asia, and sub-Saharan Africa. The consequences of political collapse and/or civil war—work migration, prostitution, intravenous drug use, defective public health resources, and poor access to good medical care—all contribute to the spread of blood-borne viruses. Inadequate infection control practices by medical establishments can lead to iatrogenic infection of children. Summaries of 4 cases in refugee children in Australia are a salient reminder of this problem.

Genetic and clinical contributions to cerebral palsy: a multi-variable analysis

AIM

This study aims to examine single nucleotide polymorphism (SNP) associations with cerebral palsy in a multi-variable analysis adjusting for potential clinical confounders and to assess SNP-SNP and SNP-maternal infection interactions as contributors to cerebral palsy.

METHODS

A case control study including 587 children with cerebral palsy and 1154 control children without cerebral palsy. Thirty-nine candidate SNPs were genotyped in both mother and child. Data linkage to perinatal notes and cerebral palsy registers was performed with a supplementary maternal pregnancy questionnaire. History of known maternal infection during pregnancy was extracted from perinatal databases.

RESULTS

Both maternal and fetal carriage of inducible nitric oxide synthase SNP rs1137933 were significantly negatively associated with cerebral palsy in infants born at less than 32 weeks gestation after adjustment for potential clinical confounders and correction for multiple testing (odds ratio 0.55, 95% confidence interval 0.38-0.79; odds ratio 0.57, 95% confidence interval 0.4-0.82, respectively). Analysis did not show any statistically significant SNP-SNP or SNP-maternal infection interactions after correction for multiple testing.

CONCLUSIONS

Maternal and child inducible nitric oxide synthase SNPs are associated with reduced risk of cerebral palsy in infants born very preterm. There was no evidence for statistically significant SNP-SNP or SNP-maternal infection interactions as modulators of cerebral palsy risk.

Maternal and perinatal risk factors for SIDS: a novel analysis utilizing pregnancy outcome data

A number of maternal and perinatal factors to increase an infant's risk of sudden infant death syndrome (SIDS) have been found in past investigations. We analysed data for potential SIDS risk factors including the presence of complications or conditions considered as detrimental to the infant's or mother's health. The data for 118 SIDS cases and 227 matched controls were obtained from a state pregnancy outcome unit. SIDS was found to be significantly more common in cases where the infant's mother was not in a relationship (i.e. divorced, separated or never married) (p = 0.005), if the infant was not the first born (p = 0.0001) and when the mother resided in a socioeconomically disadvantaged area (p = 0.03).

CONCLUSION

Overall, this SIDS cohort appears to display classical SIDS associations, and our findings are consistent with those from other regions. This novel epidemiological tool opens the way for a national Australia-wide study using pregnancy outcome data collected by the individual states and could be helpful in assessing maternal and fetal risk factors for other paediatric medical conditions.

Treatment of enterohemorrhagic Escherichia coli (EHEC) infection and hemolytic uremic syndrome (HUS)

Verotoxigenic Escherichia coli (VTEC) are a specialized group of E. coli that can cause severe colonic disease and renal failure. Their pathogenicity derives from virulence factors that enable the bacteria to colonize the colon and deliver extremely powerful toxins known as verotoxins (VT) or Shiga toxins (Stx) to the systemic circulation. The recent devastating E. coli O104:H4 epidemic in Europe has shown how helpless medical professionals are in terms of offering effective therapies. By examining the sources and distribution of these bacteria, and how they cause disease, we will be in a better position to prevent and treat the inevitable future cases of sporadic disease and victims of common source outbreaks. Due to the complexity of pathogenesis, it is likely a multitargeted approach is warranted. Developments in terms of these treatments are discussed.

Fetal and maternal candidate single nucleotide polymorphism associations with cerebral palsy: a case-control study

OBJECTIVE

Previous studies have suggested associations between certain genetic variants and susceptibility to cerebral palsy (CP). This study was designed to assess established and novel maternal and child genetic and epidemiologic risk factors for CP along with their interactions.

METHODS

DNA from 587 case and 1154 control mother-child pairs was analyzed. A panel of 35 candidate single nucleotide polymorphisms (SNPs) were examined and included SNPs in genes associated with (1) thrombophilia, (2) inflammation, and (3) risk factors for CP (eg, preterm birth). Comparisons were specified a priori and made by using a χ(2) test.

RESULTS

There were 40 fetal and 28 maternal associations with CP when analyzed by CP subtype, gestational age, genotypes of apolipoprotein E, and haplotypes of mannose-binding-lectin. After Bonferroni correction for multiple testing, no fetal or maternal candidate SNP was associated with CP or its subtypes. Only fetal carriage of prothrombin gene mutation remained marginally associated with hemiplegia in term infants born to mothers with a reported infection during pregnancy. Odds ratio directions of fetal SNP associations were compared with previously reported studies and confirmed no trend toward association.

CONCLUSIONS

Except for the prothrombin gene mutation, individual maternal and fetal SNPs in our candidate panel were not found to be associated with CP outcome. Past reported SNP associations with CP were not confirmed, possibly reflecting type I error from small numbers and multiple testing in the original reports.

A possible murine model for investigation of pathogenesis of sudden infant death syndrome

Several studies have indicated a possible causative role of toxigenic bacteria in sudden infant death syndrome (SIDS). This study examined the effect of toxigenic E. coli on pregnant and infant mice to determine if these animals could be used as a model for SIDS pathogenesis. Strains of E. coli from the intestinal contents of infants who have died of SIDS or other causes and from the faeces of healthy infants were collected over a broad time scale. The isolates were tested for their ability to produce then known toxins of E. coli and were serotyped (O and H antigens). Certain serotypes (e.g. O1:H- and O25:H1) emerged significantly more frequently from cases of SIDS than from healthy infants and isolates of these types were generally toxigenic in Vero-cell cultures but whose verotoxicity was not related to classical Shiga or other known toxins. This mouse model was developed to test the effects of these toxigenic and also non-toxigenic strains. Four apparently healthy pups aged between 17 and 21 days died unobserved overnight but no pups of the 54 control mice died suddenly (P = 0.0247, Fisher's exact test). These were considered to represent sudden unexpected deaths. Pathological effects compatible with those in SIDS were observed in mouse pups exposed to toxigenic strains indicating this model may be suitable for further study into the pathogenesis of unexpected deaths in infancy. Providing an animal model of SIDS would promote a much better avenue for studying the pathogenesis of this enigmatic condition.

A perspective on SIDS pathogenesis. the hypotheses: plausibility and evidence

Several theories of the underlying mechanisms of Sudden Infant Death Syndrome (SIDS) have been proposed. These theories have born relatively narrow beach-head research programs attracting generous research funding sustained for many years at expense to the public purse. This perspective endeavors to critically examine the evidence and bases of these theories and determine their plausibility; and questions whether or not a safe and reasoned hypothesis lies at their foundation. The Opinion sets specific criteria by asking the following questions: 1. Does the hypothesis take into account the key pathological findings in SIDS? 2. Is the hypothesis congruent with the key epidemiological risk factors? 3. Does it link 1 and 2? Falling short of any one of these answers, by inference, would imply insufficient grounds for a sustainable hypothesis. Some of the hypotheses overlap, for instance, notional respiratory failure may encompass apnea, prone sleep position, and asphyxia which may be seen to be linked to co-sleeping. For the purposes of this paper, each element will be assessed on the above criteria.

Comparison of DNA extraction methods from small samples of newborn screening cards suitable for retrospective perinatal viral research

Reliable detection of viral DNA in stored newborn screening cards (NSC) would give important insight into possible silent infection during pregnancy and around birth. We sought a DNA extraction method with sufficient sensitivity to detect low copy numbers of viral DNA from small punch samples of NSC. Blank NSC were spotted with seronegative EDTA-blood and seropositive EBV EDTA-blood. DNA was extracted with commercial and noncommercial DNA extraction methods and quantified on a spectrofluorometer using a PicoGreen dsDNA quantification kit. Serial dilutions of purified viral DNA controls determined the sensitivity of the amplification protocol, and seropositive EBV EDTA-blood amplified by nested PCR (nPCR) validated the DNA extraction methods. There were considerable differences between the commercial and noncommercial DNA extraction methods (P=0.014; P=0.016). Commercial kits compared favorably, but the QIamp DNA micro kit with an added forensic filter step was marginally more sensitive. The mean DNA yield from this method was 3 ng/μl. The limit of detection was 10 viral genome copies in a 50-μl reaction. EBV nPCR detection in neat and 1:10 diluted DNA extracts could be replicated reliably. We conclude that the QIamp Micro DNA extraction method with the added forensic spin-filter step was suitable for retrospective DNA viral assays from NSC.

The Australian cerebral palsy research study--protocol for a national collaborative study investigating genomic and clinical associations with cerebral palsy

AIM

Previous studies have proposed a link between the presence of specific single nucleotide polymorphisms (SNPs) and cerebral palsy and the majority of these associations remain to be confirmed or rejected by prospective studies with sufficient statistical power. Prior studies have also given little attention to the interaction of genomic characteristics and clinical risk factors.

METHODS

This paper describes the design of a prospective case-control study to test these genetic associations in conjunction with more stringent data collection in respect to clinical features associated with pregnancy, particularly maternal infection. Here we consider the ethical requirements, our hypothesis that genetic susceptibility modifies the risk of cerebral palsy in the presence of perinatal environmental triggers, a priori primary and secondary aims, power calculations, participant recruitment strategies, data linkage, sampling methods of genetic material and subsequent SNP analysis, collection of clinical data and the proposed final statistical analysis.

Variant interleukin 1 receptor antagonist gene alleles in sudden infant death syndrome

OBJECTIVE

To investigate if carriage of interleukin 1 (IL-1) receptor antagonist gene variants are associated with sudden infant death syndrome (SIDS) in a large cohort of case-control demographically matched infants.

DESIGN

118 SIDS and 233 control infants, who were matched to each SIDS infant by date of birth, sex, birth weight (±500 g), gestational age and ethnicity, were genotyped for an IL-1RN 89 bp tandem repeat polymorphism and analysed for significant associations.

RESULTS

No significant difference in genotype frequencies was observed between low and normal birthweight infants and year of birth (1987-1994, when the SIDS incidence was higher). In infants born between 1987 and 1994, an association was observed with SIDS and allele 2 where 18% of SIDS infants carried the 2/2 genotype compared with 9% of controls (χ(2) p=0.026, OR 2.46). Allele 3 was found at a low frequency, but was significantly more common in SIDS infants (3.1%) compared with controls (0.9%, Fisher's exact p=0.04, OR 3.76).

CONCLUSION

The higher prevalence of IL-1RN allele 2, which predisposes to poor outcomes from infection, in SIDS infants born between 1987 and 1994 (ie, prior to the dramatic decrease in SIDS incidence) suggests that the high incidence during this period could point to infection playing a role in aetiology. An association of IL-1RN allele 3 with SIDS was also found, but should be interpreted with caution due to the low frequency of this variant. The consequence of allele 3 carriage is currently unknown in the absence of functionality studies for this isoform.

Maternal HIV seroconversion at delivery without transmission

A case of HIV seroconversion associated with high viral load occurring at or near delivery is described. The management of the case in terms of prevention of mother-to-child-transmission is described and discussed in terms of the published literature and guidelines. From this instructive case a constructive strategy for delivery and immediate post-natal care is derived.

CD14 (C-260T) polymorphism is not associated with sudden infant death syndrome (SIDS) in a large South Australian cohort

Similarities have been drawn between models of endotoxic shock and gross and microscopic pathology observed in sudden infant death syndrome (SIDS) cases. Polymorphisms in genes that influence the expression of endotoxin receptors could affect the outcome of toxaemia, and could, therefore, play a role in SIDS. The CD14 gene promoter contains a single nucleotide polymorphism that affects the level of CD14 gene expression. The TT genotype of the CD14 (C-260T) polymorphism causes a significantly higher density of CD14 receptor expression on monocytes which makes the individual more sensitive to endotoxin than those with the wild-type (CC). This investigation was designed to determine whether SIDS infants have a higher frequency of the CD14 (C-260T) polymorphism compared with non-SIDS controls. One hundred and sixteen SIDS and 228 control infants were genotyped using PCR followed by restriction fragment length analysis of amplified product. Carriage of the TT or CT genotypes did not significantly differ between SIDS and control infants (P = 0.218 and 0.081, respectively). The frequencies observed in the control group were consistent with Hardy-Weinberg equilibrium and did not differ significantly from the published frequencies in Caucasian Australians. These results suggest that CD14 (C-260T) polymorphism is unlikely to be implicated in SIDS.

A polymorphism in a staphylococcal enterotoxin receptor gene (T cell receptor BV3 recombination signal sequence) is not associated with unexplained sudden unexpected death in infancy in an Australian cohort

Polymorphisms in genes that influence the expression of toxin receptors could contribute to Sudden Infant Death Syndrome (SIDS) and unexplained Sudden Unexpected Death in Infancy (uSUDI) for which there is evidence of toxin involvement. We aimed to determine whether TCRBV3S1 allele 2 could be involved in a staphylococcal toxic shock hypothesis for uSUDI. Observed frequencies of the TCRBV3S1*2 allele and genotype in 48 Australian uSUDI cases and 96 live comparison infants did not differ. In future the role of other toxin receptor gene polymorphisms deserves investigation.

Distribution of interleukin-1 receptor antagonist genotypes in sudden unexpected death in infancy (SUDI); unexplained SUDI have a higher frequency of allele 2

AIMS

This investigation was designed to explore the role of IL-1RN genotype in unexplained infant deaths (including sudden infant death syndrome (SIDS)), non-infectious infant deaths, and infectious infant deaths, and to investigate whether IL-1RN genotype is related to the finding of organisms in normally sterile sites in infant deaths.

METHODS

IL-1RN 89bp variable number of tandem repeat polymorphism genotype was determined using polymerase chain reaction for 49 cases of unexplained sudden unexpected death in infancy (uSUDI), 13 cases of infectious sudden unexpected death in infancy, 10 cases of non-infectious sudden unexpected death in infancy, and 103 live control infants. IL-1RN genotype was then compared with the presence of bacteria in normally sterile sites in infant deaths.

RESULTS

An association was found between the homozygous A2 allele and uSUDI (P = 0.007; 95% confidence interval 1.41-17.67) where carriage of the 2/2 genotype was 4.85 times more likely to increase risk of uSUDI compared with the predominant 1/1 genotype.

CONCLUSIONS

The role of infection in uSUDI and SIDS may be via an immune response pathway where IL-1RN A2 affects interleukin (IL)-1 regulation. These results are consistent with previous research where polymorphic genotypes conferring more severe proinflammatory responses are found more frequently in uSUDI/SIDS infants than in controls.

DNA from buccal swabs suitable for high-throughput SNP multiplex analysis

We sought a convenient and reliable method for collection of genetic material that is inexpensive and noninvasive and suitable for self-collection and mailing and a compatible, commercial DNA extraction protocol to meet quantitative and qualitative requirements for high-throughput single nucleotide polymorphism (SNP) multiplex analysis on an automated platform. Buccal swabs were collected from 34 individuals as part of a pilot study to test commercially available buccal swabs and DNA extraction kits. DNA was quantified on a spectrofluorometer with Picogreen dsDNA prior to testing the DNA integrity with predesigned SNP multiplex assays. Based on the pilot study results, the Catch-All swabs and Isohelix buccal DNA isolation kit were selected for our high-throughput application and extended to a further 1140 samples as part of a large cohort study. The average DNA yield in the pilot study (n=34) was 1.94 microg +/- 0.54 with a 94% genotyping pass rate. For the high-throughput application (n=1140), the average DNA yield was 2.44 microg +/- 1.74 with a >or=93% genotyping pass rate. The Catch-All buccal swabs are a convenient and cost-effective alternative to blood sampling. Combined with the Isohelix buccal DNA isolation kit, they provided DNA of sufficient quantity and quality for high-throughput SNP multiplex analysis.

Novel hypothesis for unexplained sudden unexpected death in infancy (SUDI)

OBJECTIVE

Two recent retrospective studies independently reported typically pathogenic bacteria in normally sterile sites of infants succumbing to sudden unexpected death in infancy (SUDI). These findings suggested a proportion of unexplained SUDI might be triggered by bacteraemia. The objective was to assess these observations in the context of the pathology and epidemiology of sudden infant death syndrome (SIDS) in relation to the role of infection and inflammation as triggers of these deaths.

DESIGN

A review of the literature to identify potential risk factors for unexplained infant deaths and proposal of a theoretical model for SUDI.

RESULTS

Pathologic and epidemiological evidence suggests a hypothesis based on three factors: bacterial translocation, pathogen pattern recognition insufficiency and prenatal exposure to infection.

CONCLUSION

We propose that sterile site infections in which common toxigenic bacteria are identified indicate a brief bacteraemic episode prior to death. This might reflect an ineffective innate response to invasive pathogens that results in reduced clearance of the bacteria. Thymomegaly observed consistently among infants diagnosed under the category of SIDS might have its origins in prenatal life, perhaps generated via in utero infection or exposure to microbial antigens which results in thymocyte priming. There is consistent evidence for an infectious aetiology in many unexplained SUDI. Future directions for research are suggested.

Serotypes of Escherichia coli in sudden infant death syndrome

AIM

To examine the diversity of Escherichia coli serotypes found in the intestinal contents of infants who died of Sudden Infant Death Syndrome (SIDS) compared with that in comparison infants.

METHODS AND RESULTS

Over the 3-year period, 1989-1991, in South Australia and Victoria (Australia), a total of 687 E. coli isolates from 231 patients with SIDS (348 isolates), 98 infants who had died from other causes (144 isolates) and 160 healthy infants (195 isolates) were studied. The isolates from patients with SIDS were found to represent 119 different serotypes; the isolates from 'other cause' infants represent 97 different serotypes; and the isolates from healthy infants represent 117 different serotypes. The seven common serotypes isolated most frequently from infants with SIDS belonged to those associated with extra-intestinal infections in humans. Compared to healthy infants (6%), these were found in significantly higher proportions among infants who died of other causes (13%, P < 0.05) or infants with SIDS (18.7%, P = 0.0002).

CONCLUSIONS

Despite these sources yielding a wide variety of serotypes of E. coli, a pattern of certain potential pathotypes of E. coli being associated with SIDS is apparent.

SIGNIFICANCE AND IMPACT OF THE STUDY

While SIDS remains one of the most important diagnoses of postneonatal death, its causes are still unexplained. If E. coli has a role in the pathogenesis of SIDS (as suggested by the pathotypes identified on the basis of serotype), further studies may reveal novel virulence factors that may clarify the role of this bacterium in SIDS.

Sterile site infection at autopsy in sudden unexpected deaths in infancy

OBJECTIVE

To examine and compare bacteriological findings at autopsy of cases of sudden unexpected infant death and those of deaths from other cause.

DESIGN

Autopsy report review of 130 sudden infant death syndrome (SIDS) cases (2004 definition), 32 cases of sudden unexpected death in infancy (SUDI) due to infection and 33 cases of non-infectious sudden deaths.

SETTING

Qualitative assessment of normally sterile site (NSS; heart blood, spleen or cerebrospinal fluid) bacteriology in SIDS and age-matched comparison deaths that occurred in the late 1980s and early 1990s.

MAIN OUTCOME MEASURES

Comparative sterile site bacteriological findings.

RESULTS

Sterile site infection was rare in cases of sudden accidental death (eg, motor vehicle accident or drowning); however, the finding of true pathogens such as Staphylococcus aureus in sterile sites in SIDS and deaths associated with infection was relatively common. 10.76% of SIDS had S aureus present in a sterile site, compared with 18.75% of cases of infection-related deaths. S aureus was not found in sudden accidental deaths. The incidence of coliform bacteria in NSS in SIDS was not significantly different from that seen in deaths from other cause. NSS bacteriology yielded no growth in 45.4% of sudden accidental deaths, 43% of SIDS and 28.1% of infectious causes of death.

CONCLUSIONS

The finding of S aureus in NSS in a large proportion of cases of SIDS would indicate that a proportion of these babies died of staphylococcal disease. Although the differences in NSS isolation of S aureus in the three infant groups did not quite achieve significance, on the basis of these findings and the characteristic virulence of S aureus, it is recommended that sudden unexpected deaths from which S aureus is isolated from NSS be considered for reclassification. The incidence of coliform bacteria in NSS in SIDS is not significantly different from that in deaths from another cause (both accidental and infectious). From these findings it is recommended that the opinion of a consultant microbiologist be sought to interpret microbiological findings prior to finalising autopsy reports on SUDI.

The frequency of molecular detection of virulence genes encoding cytolysin A, high-pathogenicity island and cytolethal distending toxin of Escherichia coli in cases of sudden infant death syndrome does not differ from that in other infant deaths and healthy infants

Consistent pathological findings in sudden infant death syndrome (SIDS) are seen which display similarities to the pathogenesis of toxaemic shock and/or sepsis. A key candidate infectious agent that is possibly involved is Escherichia coli, given its universal early colonization of the intestinal tract of infants and an increased frequency of toxigenic and mouse-lethal isolates from SIDS compared with comparison infants. An explanation for these findings has yet to be identified. Using PCR, we screened E. coli isolates from 145 SIDS and 101 dead control and healthy infants for three new candidate pathogenicity-related genes: clyA (cytolysin A), irp2 [high-pathogenicity island (HPI)-specific gene] and cdt (cytolethal distending toxin). The results failed to show a positive correlation with SIDS, instead proving that clyA and irp2 genes were common to the infant intestinal E. coli. Interestingly we observed a high rate of carriage of these two potentially pathogenic genes in E. coli from healthy infants in the absence of diarrhoeal disease, and we report that in a number of cases, the detection of HPI-specific genes was predictable by serotype. Despite the lack of associations defined so far, there remains the likelihood that genetic determinants influence the interactions between E. coli and the host, so these factors may be part of the multi-factorial aspect of SIDS.

Candidate genes and cerebral palsy: a population-based study

OBJECTIVE

The objective of this study was to examine whether selected genetic polymorphisms in the infant are associated with later-diagnosed cerebral palsy.

METHODS

A population-based case-control study was conducted of 28 single-nucleotide polymorphisms measured in newborn screening blood spots. A total of 413 children with later-diagnosed cerebral palsy were born to white women in South Australia in 1986-1999, and there were 856 control children. Distributions of genotypic frequencies were examined in total cerebral palsy, in gestational age groups, and by types of cerebral palsy and gender. Genotyping was performed by using a TaqMan assay.

RESULTS

For inducible nitric-oxide synthase, possession of the T allele was more common in all children with cerebral palsy and for heterozygotes who were born at term. For lymphotoxin alpha, homozygous variant status was associated with risk for cerebral palsy and with spastic hemiplegic or quadriplegic cerebral palsy. Among term infants, heterozygosity for the endothelial protein C receptor single-nucleotide polymorphism was more frequent in children with cerebral palsy. In preterm infants, the variant A allele of interleukin 8 and heterozygosity for the beta-2 adrenergic receptor were associated with cerebral palsy risk. Interleukin 8 heterozygote status was associated with spastic diplegia. Variants of several genes were associated with cerebral palsy in girls but not in boys.

CONCLUSIONS

Two of the 28 single-nucleotide polymorphisms examined were associated with all types of spastic cerebral palsy in both gestational age groups and others with cerebral palsy in gestational age or cerebral palsy subgroups. Some of these associations support previous findings. There may be a genetic contribution to cerebral palsy risk, and additional investigation is warranted of genes and gene-environment interactions in cerebral palsy.

Intrathoracic petechial hemorrhages in sudden infant death syndrome and other infant deaths: time for re-examination

The objective of this study was to provide a predictive tool to assist forensic and pediatric pathologists in the diagnosis of sudden unexpected infant death and to discuss the pathogenesis of intrathoracic petechial hemorrhages through a retrospective autopsy report review of 174 sudden infant death syndrome (SIDS) cases (2004 definition) and 67 age-matched comparison deaths. The setting was a qualitative assessment (presence or absence) of macroscopic intrathoracic petechiae in SIDS and age-matched comparison of sudden unexpected deaths that occurred in the late 1980s and early 1990s. Sensitivity, specificity, and positive and negative predictive values for thymic, pleural, and epicardial petechial hemorrhages were developed. Results showed 89.5%, 80%, and 79.9% SIDS (<12 months of age) had thymic, pleural, and epicardial petechiae, respectively, compared with 47.6%, 47.5% and 43.6% in non-SIDS deaths, respectively. Respective odds ratios were: 9.4 (4.5 to 19.9), 4.6 (2.3 to 9.1), 5.3 (2.6 to 10.8). When all 3 intrathoracic organ sites contain macroscopic petechiae, this is 84.9% predictive of SIDS; when all 3 sites have no detectable petechiae this is 93.1% predictive of a non-SIDS diagnosis. Thus, we conclude that careful assessment of intrathoracic petechiae at autopsy is likely to be diagnostically useful in the assessment of sudden unexplained infant death.

Association between Apolipoprotein E genotype and cerebral palsy is not confirmed in a Caucasian population

Apolipoprotein E (APOE) plays a significant role in lipid metabolism and has been implicated in the growth and repair of injured neurons. Two small studies have suggested an association between APOE genotype and cerebral palsy. We investigated if APOE genotype is associated with an increased risk for cerebral palsy, influences the type of cerebral palsy or interacts with prenatal viral infection to influence risk of cerebral palsy. The population-based case-control study comprised newborn screening cards of 443 Caucasian patients with cerebral palsy and 883 Caucasian matched controls. APOE genotyping was performed on DNA extracted from dried blood spots. Allelic and genotypic frequencies did not differ between cases and controls and combined frequencies were 0.10 (epsilon2), 0.76 (epsilon3), 0.14 (epsilon4), 0.03 (epsilon2/epsilon2), 0.10 (epsilon2/epsilon3), 0.03 (epsilon2/epsilon4), 0.02 (epsilon4/epsilon4), 0.21 (epsilon3/epsilon4), 0.61 (epsilon3/epsilon3). APOE genotype was correlated with cerebral palsy, type of cerebral palsy, gestation at birth and the presence of viral nucleic acids detected in previous work. Analysis by gestational age (all gestational ages, >/=37, 32-36 and <32 weeks) and type of cerebral palsy (all types, diplegia, hemiplegia and quadriplegia) showed no association between APOE genotype and cerebral palsy in this Caucasian population. An association between prenatal viral infection, APOE genotype and cerebral palsy was not demonstrated. These results did not confirm an association between APOE genotype, cerebral palsy, type of cerebral palsy and prenatal infection in a Caucasian population. Given the low frequency of APOE epsilon2 and some of the heterozygote and homozygote combinations in this study, a larger study is assessing this further.

Fetal exposure to herpesviruses may be associated with pregnancy-induced hypertensive disorders and preterm birth in a Caucasian population

OBJECTIVE

To investigate the role of fetal viral infection in the development of a range of adverse pregnancy outcomes (APOs), including pregnancy-induced hypertensive disorders (PIHD), antepartum haemorrhage (APH), birthweight <10th percentile (small for gestational age, SGA) and preterm birth (PTB).

DESIGN

Population-based case-control study.

SETTING

Laboratory-based study.

POPULATION

The newborn screening cards of 717 adverse pregnancy cases and 609 controls.

METHODS

Newborn screening cards were tested for RNA from enteroviruses and DNA from herpesviruses using polymerase chain reaction (PCR). The herpesviruses were detected using two PCRs, one detecting nucleic acids from herpes simplex virus (HSV)-1, HSV-2, Epstein-Barr virus (EBV), cytomegalovirus (CMV) and human herpesvirus (HHV)-8, hereafter designated Herpes PCR group A viruses, and the other detecting nucleic acids from varicella-zoster virus (VZV), HHV-6 and HHV-7, hereafter designated Herpes PCR group B viruses.

MAIN OUTCOME MEASURE

Odds ratios and 95% CIs for specific APOs.

RESULTS

For both term and PTBs, the risk of developing PIHD was increased in the presence of DNA from Herpes PCR group B viruses (OR 3.57, 95% CI 1.10-11.70), CMV (OR 3.89, 95% CI 1.67-9.06), any herpesvirus (OR 5.70, 95% CI 1.85-17.57) and any virus (OR 5.17, 95% CI 1.68-15.94). The presence of CMV was associated with PTB (OR 1.61, 95% CI 1.14-2.27). No significant association was observed between SGA or APH and exposure to viral infection.

CONCLUSIONS

Fetal exposure to herpesvirus infection was associated with PIHD for both term and PTBs in this exploratory study. Exposure to CMV may also be associated with PTB. These findings need confirmation in future studies.

Herpes zoster due to Oka vaccine strain of varicella zoster virus in an immunosuppressed child post cord blood transplant

A 5-year-old boy was vaccinated with the Oka strain of varicella zoster virus vaccine before cord blood transplant for chronic granulomatous disease in 2005. In 2006, he developed herpes zoster on his left arm. DNA from the vesicular rash confirmed the Oka vaccine strain of varicella zoster virus caused this complication. He responded well to 10 days of aciclovir treatment.

Genetic polymorphisms and spontaneous preterm birth

OBJECTIVE

To examine whether selected genetic polymorphisms in the infant are associated with spontaneous preterm birth (less than 37 weeks) among children with or without later-diagnosed cerebral palsy.

METHODS

Exploratory case-control study investigating the relationship of gestational age at delivery to 31 single nucleotide polymorphisms measured in newborn screening bloodspots. Among all 443 children with later-diagnosed cerebral palsy born to white women in South Australia in 1986-1999, 234 were born after spontaneous onset of labor, and 108 of these were preterm (gestational age less than 37 weeks). The comparison group was 549 infants born after spontaneous onset of labor, of whom 147 were preterm. Distributions of genotypic frequencies were examined in preterm compared with term infants with and without cerebral palsy. Genotyping was performed using a Taqman assay.

RESULTS

In children without cerebral palsy, preterm birth after spontaneous onset of labor was more frequent in association with a variant of the beta2 adrenergic receptor gene (ADRB2 Q27E, P=.003), inducible nitric oxide synthase (iNOS or NOS2A, P=.042), or thrombomodulin (G127A, P=.006). Among children with cerebral palsy, preterm birth was associated with polymorphisms in genes for endothelial nitric oxide synthase (eNOS -922, P=.012), plasminogen activator inhibitor-2 (P=.015 and .019), and alpha adducin (ADD1, P=.047).

CONCLUSION

We confirm previous observations that variants of the beta adrenergic receptor and of nitric oxide synthase are associated with prematurity, and suggest that genetic variants of the placental antifibrinolytic plasminogen activator inhibitor-2, and thrombomodulin and alpha adducin may be contributors to risk of spontaneous preterm birth.

LEVEL OF EVIDENCE

II.

A pilot study of SRL 172 (killed Mycobacterium vaccae) in healthy chronic hepatitis B carriers and hepatitis B vaccine non-responders

OBJECTIVE

To assess possible development of immunity to HBV by the use of hepatitis B vaccine in combination with the adjuvant M. vaccae (SRL 172) in healthy chronic HBsAg carriers and in healthy non-responders to hepatitis B vaccine.

HYPOTHESIS

To utilise the known immuno-stimulatory effects of SRL 172 (heat-killed M. vaccae) on chronic carriers of HBV and non-responders to hepatitis B vaccine to overcome the respective 'immune-tolerance' and 'immune blindness' observed in these conditions and develop immunity to hepatitis B.

METHOD

35 suitable healthy HBsAg carriers were randomised to receive hepatitis B vaccine together with either placebo or SRL172 by the intradermal route on one occasion. 23 HB vaccine non-responders were randomised in the same way, and similarly given vaccine with either SRL 172 or placebo. The HBsAg carrier subjects were followed-up for 12 months to monitor changes in HBV markers, anti-HBs, clinical chemistry, immunological and clinical status. The HB vaccine non-responders were reassessed for the development of anti-HBs at three months post-immunisation.

RESULTS

This pilot study provided evidence that SRL172 was moderately well tolerated and safe. One HB vaccine/placebo recipient (with initial prevaccination high HBV load) became HBV DNA negative and remained so for the 12-month duration of the study. Vaccine plus SRL172 helped induce measurably higher anti-HBs titres in HB vaccine nonresponders, however, because of relatively small participant numbers, statistically significant results were not obtained.

CONCLUSION

Based on the development of anti-HBs in non-responders, the non-proprietary mixing of vaccine with SRL172 does not destroy immunogenicity of the vaccine and thus provides an opportunity to conduct further studies of this combination in hepatitis B vaccine non-responders. HB vaccine plus SRL 172 when given on one occasion is ineffective in treating HBsAg carriers. Interesting differences between the treatment groups were observed in HB viral load responses at 3 months post-vaccination. Consideration should be given to further studies using multi-dose regimens.

Associations between fetal inherited thrombophilia and adverse pregnancy outcomes

OBJECTIVE

The purpose of this study was to investigate associations between fetal inherited thrombophilia and adverse pregnancy outcomes, including pregnancy-induced hypertensive disorders (PIHD), antepartum hemorrhage (APH), small-for-gestational age <10th percentile (SGA), and preterm birth (PTB).

STUDY DESIGN

Seven hundred and seventeen cases and 609 controls were genotyped for Factor V Leiden (FVL, G1691A), Prothrombin gene mutation (PGM, G20210A), and Methylenetetrahydrofolate reductase (MTHFR) C677T and MTHFR A1298C using DNA from newborn screening cards.

RESULTS

For babies born <28 weeks' gestation, PGM was associated with an increased risk of SGA (OR 6.40, 95%CI 1.66-24.71) and APH with SGA (OR 6.35, 95%CI 1.63-24.75). Homozygous MTHFR A1298C was associated with an increased risk of SGA for babies born 28-31 weeks gestation (OR 4.00, 95%CI 1.04-15.37), and with APH and SGA for babies born <32 weeks' gestation (OR 3.57, 95%CI 1.09-11.66). Homozygous MTHFR C677T was associated with a reduced risk of PTB and SGA (OR 0.52, 95%CI 0.28-0.96) for babies born 32 to 36 weeks' gestation. Homozygous FVL decreased the risk of PTB <32 weeks' gestation (OR 0.55, 95%CI 0.31-0.98).

CONCLUSION

Fetal thrombophilic polymorphisms may be related to adverse pregnancy outcomes, in particular SGA.

The association between inherited cytokine polymorphisms and cerebral palsy

OBJECTIVE

The purpose of this study was to investigate associations between inherited cytokine polymorphisms and cerebral palsy.

STUDY DESIGN

This was a case-control study that used DNA from the newborn infant screening cards of 443 white infants with cerebral palsy and 883 white control infants to test for the following cytokine polymorphisms: tumor necrosis factor-alpha-308, mannose-binding lectin-221, and 3 polymorphisms in exon-1 of the mannose-binding lectin gene at codon-52, -54, and -57.

RESULTS

At all gestational ages mannose-binding lectin codon-54 increased the risk of the development of diplegia (homozygous or heterozygous odds ratio, 1.55; 95% CI, 1.03-2.32). For babies who were born at term, the risk of the development of quadriplegia was associated with heterozygous tumor necrosis factor-alpha (odds ratio, 1.82; 95% CI, 1.04-3.15), and mannose-binding lectin codon-54 was associated with diplegia (homozygous or heterozygous odds ratio, 2.12; 95% CI, 1.10-4.05). The presence of any polymorphism in mannose-binding lectin exon-1 at term approximately doubled the risk of the development of diplegia (odds ratio, 1.94; 95% CI, 1.05-3.62). Homozygous or heterozygous tumor necrosis factor-alpha was associated with hemiplegia for babies who were born at <32 weeks of gestation (odds ratio, 2.38; 95% CI, 1.02-5.58). Overall, the presence of any cytokine polymorphism was associated with cerebral palsy (odds ratio, 1.37; 95% CI, 1.02-1.84).

CONCLUSION

Carriage of polymorphisms in the tumor necrosis factor-alpha and mannose-binding lectin genes are associated with an increased risk of cerebral palsy.

Neurotropic viruses and cerebral palsy: population based case-control study

OBJECTIVE

To investigate the association between cerebral palsy and direct evidence for perinatal exposure to neurotropic viruses.

DESIGN

Population based case-control study.

SETTING

Adelaide Women's and Children's Hospital Research Laboratory.

PARTICIPANTS AND MAIN OUTCOME MEASURES

Newborn screening cards of 443 white case patients with cerebral palsy and 883 white controls were tested for viral nucleic acids from enteroviruses and herpes viruses by using polymerase chain reaction. Herpes group A viruses included herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpes virus 8 (HHV-8), and herpes group B viruses included varicella zoster virus (VZV) and human herpes viruses 6 and 7 (HHV-6 and HHV-7).

RESULTS

The prevalence of viral nucleic acids in the control population was high: 39.8% of controls tested positive, and the prevalence was highest in preterm babies. The detection of herpes group B viral nucleic acids increased the risk of developing cerebral palsy (odds ratio 1.68, 95% confidence interval 1.09 to 2.59).

CONCLUSIONS

Perinatal exposure to neurotropic viruses is associated with preterm delivery and cerebral palsy.

Cefotaxime and ceftriaxone cerebrospinal fluid levels during treatment of bacterial meningitis in children

Cefotaxime (CTX) and ceftriaxone (CRO) were compared for cerebrospinal fluid (CSF) penetration and antimicrobial efficacy in cases of bacterial meningitis in children. This was a comparative study of CRO (100mg/kg once daily) and CTX (50 mg/kg 6 hourly) in the treatment of children with bacterial meningitis. The aetiological agents included Streptococcus pneumoniae (SPn), Haemophilus influenzae type b (Hib) and Neisseria meningitidis (NMen). Minimum inhibitory concentrations (MICs) were measured. In 33 patients from whom a second CSF specimen was obtained, CSF was cultured and assayed for antibiotic concentration. Median MICs of CTX and CRO for SPn, Hib and NMen were 0.01 and 0.01 microg/mL, 0.004 and 0.002 microg/mL and 0.008 and 0.004 microg/mL, respectively. All 33 repeat lumbar puncture specimens were sterile. The lowest CSF level recorded (0.45 microg/mL for CTX) was 45 times the MIC (0.01 microg/mL). The highest levels (24-35 microg/mL for CRO) were up to 8750 times the MIC of the patient's causative organism. A wide range of CSF levels for both antibiotics was observed. Levels varied with post-dose interval and duration of illness. On the basis of these findings, clinicians should be reassured that repeat lumbar puncture is not recommended for the causative organisms in this study (i.e., for Hib, NMen and penicillin/cefotaxime/ceftriaxone fully-susceptible SPn).

SIDS pathogenesis: pathological findings indicate infection and inflammatory responses are involved

This article explores the pathological evidence that supports the hypothesis that infection and inflammation are underlying mechanisms in SIDS. It reviews the pathological findings in relation to the risk factors reported for SIDS and compares these findings with other hypotheses suggested as causes of these unexplained deaths in infants. The roles of environmental factors and bacterial products such as soluble curlin detectable in SIDS sera in triggering cytokine cascades and aberrant inflammatory responses resulting in a toxic shock-like event are also explored. Areas for future research are outlined.

Sudden infant death syndrome: a critical review of approaches to research

This review explores the various research approaches taken attempting to solve the problem of SIDS. It would appear that major clues provided by pathological findings have been largely overlooked and as a consequence much effort, time, and money has been wasted on projects that satisfy only sub-specialty and political needs. Close examination of the pathological clues would provide better insights into the mechanisms underlying this enigmatic and heartbreaking problem.

Antenatal causes of cerebral palsy: associations between inherited thrombophilias, viral and bacterial infection, and inherited susceptibility to infection

Cerebral palsy rates of 2 in every 1,000 births have varied little over the last 40 years, despite improvements in obstetric care. In the past, cerebral palsy was thought to be due to poor obstetric care and management; however, epidemiological studies have refuted this, suggesting that there is usually an antenatal timing to the neuropathology of cerebral palsy. There are many known risk factors for cerebral palsy, including multiple gestation, prematurity, and low birth weight. Recently, intrauterine infection, maternal pyrexia, and the presence of thrombophilic disorders (thrombophilia) have been identified as major risk factors for subsequent cerebral palsy. This review examines the links between intrauterine infection, the fetal inflammatory response, and thrombophilia as possible causes of cerebral palsy. The interactions of viral or bacterial infections during pregnancy, normal or abnormal fetal cytokine responses, and hereditary fetal thrombophilias as antenatal causes of the neuropathology of cerebral palsy are now areas of research priority.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the condition cerebral palsy, list the risk factors for the development of cerebral palsy, outline the ultrasound findings associated with cerebral palsy, and point out other conditions associated with cerebral palsy.

Childhood tetanus in Australia: ethical issues for a should-be-forgotten preventable disease

Refusal of a parent to have a child vaccinated against tetanus raised ethical issues for the treating clinicians. The clinicians felt their duty to the child was compromised, but recognised that our society leaves the authority for such decisions with the parents. As there was no reason, other than different beliefs about vaccination, to doubt the parent's care for the child, the clinicians limited their response to providing strong recommendations in favour of vaccination. Other issues raised by this case include community protection, and the costs to the community of treating a vaccine-preventable disease.