No abstract

Viral pollution of the river water in Toyama City was surveyed during the two‐year period from July 1979 to July 1981, and the ecology of viruses in the river water is discussed. Virus isolation from the river water samples, or from the water squeezed from cotton pads that were immersed in the stream for 3 days, was carried out by the “filter adsorption/elution” method.River waters were found to be contaminated with various species of enteric viruses, that is, poliovirus, echovirus, coxsackievirus, adenovirus, and reovirus. Poliovirus was isolated during the period immediately after the oral administration of polio vaccine, and Coxsackie B virus was frequently isolated all year around. The enterovirus concentration in the river water was significantly high with a maximum of five plaque‐forming units of Coxsackie B2 virus per 250 ml.The species and type distribution of enteroviruses isolated from the river water coincided well with that of viruses isolated from inhabitants of Toyama Prefecture, with the exception of reovirus which was the largest population of virus species in the river water.

Mice were protected from lethal infection with mouse adenovirus (M-Ad) by adoptive transfer of immune spleen cells (ISC) that were prepared from mice immunized with MAd and not protected by sonicated ISC. However, a similar extent of protection was also observed by passive immunization with anti-MAd serum. In contrast, by in vitro experiments ISC were shown to be able to interrupt intracellular multiplication of MAd , whereas sonicated ISC, unimmunized mouse spleen cells, or anti-MAd serum were unable to do so. ISC were inhibitory in vitro when added within 12 h postinfection but not when added later. The inhibitory activity of ISC was regarded as due to cell killing by ISC, since the trypan blue exclusion test showed that about 80% of infected cells were killed by ISC even when 5'-fluorodeoxyuridine was added to the cells to block viral deoxyribonucleic acid synthesis, under which conditions control infected cells, to which ISC were not added or normal spleen cells were added, were kept alive at least for a few days. Kinetics studies in MAd infected mice showed that the inhibitory activity of ISC became highest at 1 to 2 weeks postinfection and faded away thereafter in a few weeks, whereas serum antibody titer assayed by passive hemagglutination reached its peak level at about 4 weeks postinfection and declined gradually thereafter.

Reoviruses (reos)

No abstract