| molecular analysis of neorickettsia risticii in adult aquatic insects in pennsylvania, in horses infected by ingestion of insects, and isolated in cell culture. | upon ingestion of adult aquatic insects, horses developed clinical signs of potomac horse fever, and neorickettsia risticii was isolated from the blood. 16s rrna and 51-kda antigen gene sequences from blood, isolates, and caddis flies fed to the horses were identical, proving oral transmission of n. risticii from caddis flies to horses. | 2002 | 11825999 |