#cot death /crib death Fortunately, crib deaths are rare. The cause is unknown but usually the victim is under 6mths. Research indicates that most deaths are not caused by {asphyxia}. It is thought to be caused by a {virus} infection which overwhelms the {immune system}. There are no obvious symptoms & can strike down a perfectly healthy baby when asleep. Apneic attacks are also rare, but cause breathing to stop, & unless aroused & stimulated, may be fatal. {Apnea} mattresses are available which monitor breathing & sound an alarm if breathing stops.