[Sudden death of a two-year-old boy with influenza A virus infection: study of an autopsy case]

Sudden and Fulminant Deaths of Healthy Children in Italy during the 2010-11 and 2011-12 Seasons: Results of an Online Study

The 2009 pandemic in Italy has been viewed as a false alarm, and it has not been properly understood based on historical precedents and more in-depth studies that have been conducted in other countries. Some of these studies have pointed to a phenomenon of sudden and fulminant death among healthy children, which is not the sole prerogative of pandemic influenza, but was, in 2009, a more frequent occurrence than in previous years. The purpose of this study is to gather such cases occurring during the 2010-11 and 2011-12 seasons. Google Search was used in order to find cases of children and teens with no reported preexisting conditions of relevance and who died suddenly and unexpectedly after exhibiting flu-like symptoms during the two seasons. During the 2010-11 season, 29 deaths were found to meet the above conditions, 18 of which were fulminant and 11 sudden. For the 2011-12 season, there were ten such cases: five fulminant and five sudden. Most of these cases occurred during the period of maximum circulation of the flu virus. Fulminant deaths were three times more frequent during 2010-11 season and involved children of a higher average age than the more recent season. It is not possible to come to any definite conclusions, but there is reason to suspect that the driver of this significant increase may be the A(H1N1)pdm09 virus. Regardless of how reading these results, it is advisable that the surveillance systems be strengthened and more recent study techniques be adopted in order to determine the causes of similar deaths in the future.

[Seasonal flu]

La grippe saisonnière est due aux virus influenza A et B. Il s’agit de virus enveloppés dont le génome est constitué de sept à huit fragments d’ARN. Les différents sous-types sont déterminés par la nature des deux glycoprotéines de surface HA et NA. La grippe saisonnière est une maladie épidémique et hivernale dans les zones à climat tempéré. Son épidémiologie est liée à la grande variabilité du virus au cours du temps, nécessitant la mise en place d’un système d’alerte détectant chaque année les variants circulants dominant et déterminant la composition vaccinale. Les symptômes cliniques de la grippe ne sont pas suffisamment spécifiques pour permettre le diagnostic sans examen virologique. Cela est particulièrement vrai en période non épidémique, chez les sujets de plus de 65 ans et chez les enfants de moins de cinq ans. L’enfant représente une cible privilégiée des infections à virus influenza. Le recours à l’hospitalisation est d’autant plus élevé que l’enfant est jeune. Chez le nourrisson, l’infection peut être paucisymptomatique et s’accompagner de manifestations non respiratoires (léthargie, convulsions, malaises). Le diagnostic virologique de la grippe est justifié chez tous les sujets hospitalisés pour un syndrome respiratoire compatible avec une infection à virus influenza. Il existe plusieurs outils permettant une recherche directe du virus dans les sécrétions respiratoires : isolement du virus en culture, détection d’antigènes, détection moléculaire de l’ARN. Le choix de la méthode se fait selon les caractéristiques du test : sensibilité, spécificité, rapidité et simplicité de réalisation, coût.

Virological analysis in the diagnosis of sudden children death: A medico-legal approach

Infections are considered to be an important cause of unexpected death in children. It has also been assumed that respiratory viruses are involved in the genesis of sudden infant death syndrome (SIDS). The Spanish National Institute of Toxicology and Forensic Sciences act as the forensic reference centre for Spain. We analyse the experience of this centre in the virological study of 64 cases of sudden children death where viral serology, virological cultures, herpesviruses polymerase chain reaction (PCR) and electron microscopy were performed. According to pathological findings, death could only be attributed to an adenovirus infection in one amygdalitis with upper airways stenosis and asphyxia. Human herpes virus 6 (HHV-6) was detected by PCR in one case with pathological findings characteristic of SIDS. Recent infection by respiratory syncytial virus (RSV), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were also detected. Meanwhile, 85.9% of the cases yielded negative viral results. Twenty-eight infants were finally categorised as SIDS. Pathological findings of infection were detected in 12 patients despite the negativity of viral analyses. Although viral infection is an uncommon cause of sudden children death, a complete microbiological investigation will help to solve the puzzle of SIDS. Definitive guidelines for microbiological analyses need to be updated whilst new pathogens are discovered or new techniques are implemented in order to clarify unsolved cases.