V. Evaluation of Cross-Immunity against Type 1 Dengue Fever in Human Subjects Convalescent from Subclinical Natural Japanese Encephalitis Virus Infection and Vaccinated with 17D Strain Yellow Fever Vaccine
Amebic hepatitis was induced in hamsters by the intrahepatic injection of Endamoeba histolytica and bacterial associates from 24-hour cultures. Drugs were administered twice daily for 4 days, with the first doses being given approximately 5 hours before infection. The effects of therapy were determined 92 hours after infection. This included comparison of treated and untreated groups of animals with respect to the proportion infected with amebas and the mean hepatic lesion weight. The criterion of the presence or absence of amebas was substantially dependent upon lesion size and added essentially no independent information.
Emetine, chloroquine, amodiaquin (Camoquin) and quinacrine were highly effective in suppressing lesion development. Emetine was given intramuscularly; the other drugs were given orally. In the case of quinacrine, eradication of amebas corresponded with 97 per cent reduction in lesion weight. Carbarsone, chloramphenicol and aureomycin were administered orally and each caused slight suppression of lesions. Penicillin and dihydrostreptomycin, administered jointly by the subcutaneous route, were essentially ineffective.
The advantages and disadvantages of the test procedure as a means of selecting new agents for trial in extra-intestinal amebiasis are discussed.