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Echovirus type 33 (E33) is a relatively uncommon enterovirus. An E33 outbreak during the winter of 2000 in New Zealand led to 75 virologically-confirmed cases of E33 infection (2.6 cases per 100,000 individuals). Sixty-six (88%) of the 75 patients were aged <30 years, with the highest rates of infection recorded in Maori and Pacific ethnic groups. Overall, 47 (84%) of 56 patients whose cases were analyzed had either aseptic meningitis or encephalitis. Central nervous system involvement was more common after infancy (43 of 45 non-infant patients vs. 4 of 11 infants [relative risk, 2.6; 95% CI, 1.5-4.3]). Two infants died, including a neonate with fulminant hepatitis. Independent of symptom duration, neutrophil-predominant pleocytosis was detected in 17 (41%) of 41 cerebrospinal fluid specimens. Virus isolates could not be definitively typed by antibody neutralization testing but were identified as E33 by partial sequencing of the VP-1 capsid gene. The isolates were closely related to strains from Australia and Oman. Molecular typing, together with a serotype-specific E33 PCR, improved the speed and effectiveness of the outbreak investigation. [ABSTRACT FROM AUTHOR]

On Feb 1, 2002, inactivated poliomyelitis vaccines replaced live-attenuated oral poliovirus vaccine (OPV) in New Zealand's immunisation schedule, allowing systematic monitoring of OPV virus circulation. Findings of paediatric-inpatient surveillance indicate that 7% of children excreted polioviruses before this switch, but none did so 1 month afterwards. Acute flaccid paralysis surveillance detected no poliovirus during and after the switch, whereas enterovirus surveillance detected poliovirus only once during the switch. Environmental surveillance identified polioviruses in sewage samples until May, 2002, after which they were detected infrequently. Intratypic differentiation and sequencing showed that all polioviruses were Sabin-like. Multiple surveillance methods hence showed that OPV strains did not persist for extended periods after a vaccine switch in a developed country with a temperate climate. Sequence homology with Sabin vaccine parent strains indicated that polioviruses detected more than 4 months after the switch were of recent origin, consistent with importation from OPV-using countries. [ABSTRACT FROM AUTHOR]

Echovirus type 33 (E33) is a relatively uncommon enterovirus. An E33 outbreak during the winter of 2000 in New Zealand led to 75 virologically-confirmed cases of E33 infection (2.6 cases per 100,000 individuals). Sixty-six (88%) of the 75 patients were aged <30 years, with the highest rates of infection recorded in Maori and Pacific ethnic groups. Overall, 47 (84%) of 56 patients whose cases were analyzed had either aseptic meningitis or encephalitis. Central nervous system involvement was more common after infancy (43 of 45 non-infant patients vs. 4 of 11 infants [relative risk, 2.6; 95% CI, 1.5-4.3]). Two infants died, including a neonate with fulminant hepatitis. Independent of symptom duration, neutrophil-predominant pleocytosis was detected in 17 (41%) of 41 cerebrospinal fluid specimens. Virus isolates could not be definitively typed by antibody neutralization testing but were identified as E33 by partial sequencing of the VP-1 capsid gene. The isolates were closely related to strains from Australia and Oman. Molecular typing, together with a serotype-specific E33 PCR, improved the speed and effectiveness of the outbreak investigation.