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
Two white rats have been infected with relapsing fever by inoculating them with a suspension of macerated naturally infected ticks, Ornithodoros talaje.
Typical spirochaetes have been found in naturally infected ticks in Panama.
One monkey, Macaccus rhesus, has been infected with the relapsing fever of Panama by feeding a number of larvae (O. talaje) upon an infected white rat and twenty-two days later allowing the same ticks as first stage nymphs to feed on the monkey.
Three human beings, volunteer patients, have been infected with relapsing fever as follows:
1.The first by a subcutaneous injection of blood from a white rat which had been infected with relapsing fever by a combined subcutaneous and intraperitoneal injection of naturally infected ticks.
2.The second by a hypodermatic injection of a suspension of naturally infected ticks.
3.The third by being bitten by naturally infected ticks.
Tabulations of the results obtained by inoculating white rats, white mice and monkeys, Macaccus rhesus, with the spirochaetes of the relapsing fever in Panama are presented. Also a brief allusion is made to their measurements and appearance in cultures.