A recent epidemic of acute hemorrhagic conjunctivitis.

The coxsackievirus A24 variant was implicated in four of six major acute hemorrhagic conjunctivitis outbreaks in Singapore since its discovery in 1970. Hela cell suspension in 24-well flat-bottom tissue culture plates was a satisfactory alternative to monolayer cells grown in test tubes for virus isolation. Respiratory illness occurred in 20 of 98 patients with acute hemorrhagic conjunctivitis.

Poliovirus neutralising antibody in infants and cord blood.

Singapore participated in the WHO EPI protocol for rapid assessment of serological response to three doses of standard oral poliovirus vaccine. The 100% seropositive finding of thirty infants below one year old is no proof of seroconversion rate to the Trivalent Oral Poliovirus Vaccine (TOPV) administered. Investigation of 100 cord blood samples showed that passively transferred maternal poliovirus neutralising antibody cannot be relied upon for protection of infants against poliomyelitis.

Phylogenetic analysis of a coxsackievirus A24 variant: the most recent worldwide pandemic was caused by progenies of a virus prevalent around 1981.

Nucleotide substitutions in the viral-encoded proteinase 3C (3Cpro) region (549 nucleotides) of the RNA genome of a coxsackievirus A24 variant (CA24v), one of the agents causing acute hemorrhagic conjunctivitis (AHC), were studied using 32 isolates collected from the Eastern hemisphere in 1970-1989. Based on regression analysis of nucleotide differences among isolates, the nucleotide substitution rate of CA24v 3Cpro was estimated to be 3.7 x 10(-3)/nucleotide/year.

Evolutionary study on the Coxsackievirus A 24 variant causing acute hemorrhagic conjunctivitis by oligonucleotide mapping analysis of RNA genome.

The evolution of the variant of Coxsackievirus A 24 (CA 24 v) which causes acute hemorrhagic conjunctivitis was explored. Using 15 isolates obtained from Southeast Asia during the period 1970-1986, the genetic distance between isolates was estimated from pairwise comparison of nucleotide changes deduced from common spots on oligonucleotide maps of the isolates. From regression analysis of the genetic distance and the time of isolation of the isolates, the evolutionary rate of CA 24 v was estimated to be 3.