The role of infection in sudden infant death syndrome

Abstract

Studies on the potential role of infectious agents in sudden infant death syndrome (SIDS) have been published over the years in a variety of journals. The aim of this special issue of FEMS Immunology and Medical Microbiology is to bring together a group of the most recent studies from Europe, Australia and Canada which cover epidemiology and laboratory studies examining hypotheses relating to infection and inflammation in SIDS. The articles in this issue examine evidence for the involvement of specific micro-organisms in SIDS and the problems relating to experimental studies on infection in relation to the underlying pathology of these deaths. There is an update on the evidence for the common bacterial hypothesis proposed in 1987 examining risk factors identified in epidemiological studies, particularly how the prone sleeping position could affect bacterial colonisation or induction of toxins. Evidence for induction of inflammatory responses in SIDS infants is reviewed and the relation of these responses to mechanisms proposed as causes of death assessed. Factors found to be associated with reduction of the risk of SIDS (breast feeding and immunisation) are examined in relation to some of the toxigenic bacteria implicated in these deaths. Finally, the high incidence of SIDS in some ethnic groups is examined as a potential model to investigate the contributions of genetic, environmental and cultural differences to susceptibility of infants not only to SIDS but to serious respiratory tract infections.

Possible Pathomechanisms of Sudden Infant Death Syndrome

“…Prone sleeping and exposure to cigarette smoke are important factors favoring the development of SIDS. 1,12 Recently, Krous et al 12 even reported that in their group of SIDS infants, both the percentage of positive upper respiratory tract cultures (80% vs. 89%, respectively) and pathologic inflammatory lymphocytic infiltrations of the bronchi, bronchioles, and pulmonary interstitium were similar to those found in controls. 6 Several authors believe that SIDS is a pathophysiologic reaction to bacterial toxins, viruses, and/or cigarette smoke effects during the early stage of developmental age when defense reactions of the organism are less effective in neutralizing inflammatory mediator effects.…”

“…1 Accounting for 2529 deaths in 1998 in the United States, SIDS is the third leading cause of infant mortality (8.9%) after congenital anomalies (22%) and short gestation/low birth weight (14%). 1 Accounting for 2529 deaths in 1998 in the United States, SIDS is the third leading cause of infant mortality (8.9%) after congenital anomalies (22%) and short gestation/low birth weight (14%).…”

“…1 Accounting for 2529 deaths in 1998 in the United States, SIDS is the third leading cause of infant mortality (8.9%) after congenital anomalies (22%) and short gestation/low birth weight (14%). 1,3 The risk factors of SIDS include male gender, age 2 to 4 months, prematurity, low birth weight, poor prenatal medical care, low socioeconomic status of the family, young age of parents, parental low educational level, short periods between pregnancies, multiple pregnancy, drug intake by pregnant woman, winter months, prone sleeping, exposure to cigarette smoke during pregnancy and after birth, and overheating. 1,3 The risk factors of SIDS include male gender, age 2 to 4 months, prematurity, low birth weight, poor prenatal medical care, low socioeconomic status of the family, young age of parents, parental low educational level, short periods between pregnancies, multiple pregnancy, drug intake by pregnant woman, winter months, prone sleeping, exposure to cigarette smoke during pregnancy and after birth, and overheating.…”

The role of infection and inflammation in sudden infant death syndrome

“…Many SIDS infants have a history of a mild viral illness that precedes death but is not thought to be its cause (2, 11, 12). Increased incidence of SIDS in winter months parallels closely a susceptibility to infections, particularly those of the respiratory tract.…”

Microbiological findings in sudden unexpected death in infancy: comparison of immediate postmortem sampling in casualty departments and at autopsy

“…A p value less than 0.05 was considered significant. Positive cultures were specifically classified according to whether ‘group 2 pathogens’ were present, these being organisms that may be clinically associated with bacteraemic septic shock in the absence of an identifiable focus of infection, as previously defined 6 9…”