Epidemiological and virological studies of echovirus type 4 meningitis in Japan, 1964

Laboratory surveillance of viral meningitis by examination of cerebrospinal fluid in Cape Town, 1981-9

Nine years accumulated laboratory data derived from the culture of the cerebrospinal fluid of 11,360 aseptic meningitis cases were retrospectively reviewed to establish the epidemiology of viral meningitis in Cape Town. Virus was isolated from 3406 of the cases (91% enteroviruses and 9% mumps). Five major summer viral meningitis episodes were documented: two of echovirus 4 (706 and 445 cases), echovirus 9 (223), coxsackie A9 (104) and one of unidentified enterovirus (324 cases--probably echo 9). Although coxsackie B was endemic, clusters of one or other type were dominant at any one time. Mumps was endemic. Sixty-two percent of all viral cases were < 5 years old. The median ages of 4 and 5 years in echoviruses 9 and 4 (the epidemic strains) contrasted with that of 1 year in coxsackie B (with many cases < 3 months old). Mumps peaked at 3-4 years of age. Males dominated overall, particularly in mumps.

Neutralization activity of some Coxsackie B3 antibodies is compromised by protein factor(s) secreted by Vero cells

When various anti-Coxsackie B3 virus antibodies were examined for the neutralizing activity in cultures under liquid medium, some antibodies including monoclonal antibodies gave abnormally low titers in the neutralization test in Vero cells, in comparison with the other cells such as HeLa, FL, HEp-2, or primary monkey kidney cells. The neutralization titer of these antibodies was, however, similar in all these cells by plaque reduction assays under agar overlay, i.e., the above phenomenon was restricted to cultures under liquid medium. The reduced neutralization titer in Vero cells under liquid medium was found to be brought about by protease-sensitive factor(s) released by Vero cells, because (1) the addition of Vero cell culture fluid resulted in a marked reduction of neutralizing titer in primary monkey kidney cells, and (2) the activity of the Vero cell factor was destroyed by trypsin (20 micrograms/ml for 1 h). As three-day incubation of virus-antibody complex in Vero cell culture fluid resulted in a partial restoration of virus infectivity, the binding of antibody to virions appears to be competed by the Vero cell factor.

Etiology of sporadic aseptic meningitis in children in the Leningrad area

The etiology of sporadic aseptic meningitis among children in the Leningrad area in 1974 was studied. 184 patients and 284 healthy children of the same age groups were studied; altogether 540 stool specimens and 99 cerebrospinal fluid specimens were collected for virus isolations and 162 pairs of sera for virus antibody assays. Mumps virus infection was the etiology of the disease only in 5% of cases. The main etiological role of enteroviruses was proved. Strains most often associated with disease were echoviruses 6 and 14, coxsackievirus A9 and nontypable strains. Additional strains isolated were echoviruses 2, 9, 11 and 20.

Optimal conditions for plaque assay of echoviruses in human embryonic lung fibroblast cells

The present paper gives optimal conditions for plaque assays tn human embryonic lung fibroblast cells with 45 echoviruses including 11 fresh isolates, covering 31 serotypes. All the viruses tested except echovirus type 23 produced plaques at a high titer in the same cells by the methods described in this communication. Plaque formations by a number of strains were markedly enhanced in size or number or both by the addition of polycation.

An epidemic associated with echovirus type 18

During the period October 1968 to March 1969 echovirus type 18 was isolated from 83 patients investigated at Fairfield Hospital for Communicable Diseases, Melbourne. The illnesses most commonly associated with these isolations were aseptic meningitis, and fever with rash.We believe that this is the first report of an epidemic due to echovirus type 18 and the first occasion on which this virus has been shown to produce disease in adults.