Complement-fixing antibodies to rickettsial antigens in sera of primates

A survey for rickettsial antibodies in the sera of humans, gorillas, chimpanzees, orangutans, gibbons, baboons, marmosets, rhesus, cynomolgus and African green monkeys was performed. All of the species, except marmosets, had antibodies for the OX-2, OX-19 and OX-K antigens as tested in the Weil-Felix reaction. Seroconversions were noted in gorillas, chimpanzees and orangutans. Complement-fixation testing with rickettsial antigens showed the presence of antibodies for Q fever in all species except the gorilla. No antibody was detected for epidemic typhus and only one of the sera showed antibody for endemic typhus. Antibodies for spotted fever and rickettsial pox, on the other hand, were more frequently detected, being quite common in baboons and African green monkeys. The significance of the difference in results obtained with the Weil-Felix and complement-fixation tests is discussed.