Aggregation as a factor in loss of viral titer in seawater

The failure of a large percentage of previously monodispersed virus added to artificial seawater to pass through membrane filters which would exclude the passage of aggregates indicated that extensive aggregation was taking place in artificial seawater. The loss of viral titer in artificial seawater was found to be directly related to salinity as was the extent of aggregation. Aggregation also appeared to be taking place in natural seawater, but was not as extensive. Viral clumps formed in both natural and artificial seawater could be disaggregated by an increase in the amount of organic matter or a decrease in salinity. Aggregation may play a role in the initial decline of viral titer in seawater, as well as to reduce the number of "infectious foci" present in seawater.