Type A2 Influenza Viral Infections in Children

Abstract

\s=b\We retrospectively reviewed the manifestations of influenza A2 in 83 hospitalized young children. Our purpose was to define the spectrum of clinical illness in this age group. Findings included fever (91%), vomiting or diarrhea (49%), pharyngitis (34%), pneumonitis (29%), otitis media (24%), conjunctivitis (13%), croup (13%), and bronchiolitis (6%). Neuromuscular manifestations occurred in 16 patients (19%) and included seizures, apnea, opisthotonos, and myositis. Three children had cerebrospinal fluid pleocytosis. Children younger than 3 months of age had fever less often and gastrointestinal symptoms more often than older children. Three children died of progressive pneumonitis. We conclude that influenza A may cause a wide range of respiratory and neurologic findings in infancy and early childhood.

Seasonal and Pandemic Human Influenza Viruses Attach Better to Human Upper Respiratory Tract Epithelium than Avian Influenza Viruses

“…[13][14][15][16][17][18][19][20][21][22] The similarity that we found between pandemic H1N1 virus and seasonal influenza viruses for the attachment to the URT corresponds to the similarity between these viruses for attachment to the trachea. 23 Our virus histochemistry data on HPAIV H5N1 and other avian influenza viruses correspond with some previous studies, but not with others.…”

Influenza A Infection Is an Important Cause of Febrile Seizures

“…18,19 The incidence of convulsion associated with influenza A infection had been re- ported to range from 6% to 40%. [12][13][14][15] The large variation in the incidence of febrile seizure associated with influenza A seen in different studies can be partially explained by differences in age. 15 In other studies, the patient population was heavily skewed in favor of those with severe complications, including convulsions.…”

“…Some reports have included children with underlying causes for seizures, and their relevance to the pathogenesis of febrile seizures is limited. [12][13][14][15] In 1998, a new influenza A antigenic variant, the H3N2 Sydney virus, appeared in Hong Kong. Some pediatricians had the impression that febrile seizures associated with this new variant were more common that previously seen with influenza A.…”

Efficacy of Zanamivir against Avian Influenza A Viruses That Possess Genes Encoding H5N1 Internal Proteins and Are Pathogenic in Mammals

“…The mechanism(s) for spread through the blood-brain barrier is not clearly understood and is probably related to a specific viral protein(s). Although neurologic disorders associated with influenza in humans are rare, there are reports of neurologic disorders associated with H3N2 and B strains of human influenza virus (23,24,32,35). Although the Spanish influenza virus of 1918 has not been causally associated with encephalitis lethargica, the question remains open until further evidence is accumulated.…”