Studies have recently been published of surveys of antibodies to common respiratory viruses in human sera from several parts of the world. The present article reports the findings of a survey of antibodies to two more viruses (adenovirus type 8 and coxsackievirus type A21) in human sera mainly collected from six widely separated geographical regions (Alaska, England, Marshall Islands, Sarawak, South-West Africa and Tunisia).A world-wide geographical distribution of infection with these two viruses was found. However, antibodies to individual viruses were not found with the same frequency in all countries; and, in marked contrast to the findings in the earlier surveys of antibodies to the common respiratory viruses, the frequency of antibodies was not the same for each virus in sera from the same country. It was not possible to draw any final conclusions as to the reasons for the observed differences.
We report the virological and clinical features of 8 children who presented with adenovirus-associated acute flaccid paralysis (AFP) during an epidemic of enterovirus type 71 (EV71)-associated hand-foot-and-mouth disease (HFMD) in Sarawak, Malaysia, in 1997. Neutralization tests and phylogenetic analysis revealed adenovirus type 21 (Ad21), although DNA restriction digests suggested that this virus was different from the prototype Ad21. Four children had upper-limb monoparesis, 2 had lower-limb monoparesis (one of whom had changes in the anterior spinal cord noted on magnetic resonance imaging), and 2 had flaccid paraparesis. At follow-up, 4 children were noted to have made full recoveries and 3 had residual flaccid weakness and wasting. Neurophysiological investigation revealed a mixture of axonal and demyelinating features in motor and sensory nerves, with denervation. These findings suggest that Ad21 might cause AFP by anterior horn cell damage or neuropathy of the brachial or lumbosacral plexus. The occurrence of these unusual adenovirus infections during an outbreak of EV71-associated HFMD suggests that an interaction between the 2 viruses may have occurred.