Abstract
The importation of tropical psittacine birds from South America and Australia is always connected with considerable risk in bringing psittacosis to zoölogical gardens, pet stores, aviaries, and breeding establishments of fanciers 1 2 3 since latent infections, which may relapse or become activated in transit, are fairly common. As a rule, the existence of psittacosis in a shipment is established by autopsies and the inoculation of mice with the spleens of the few birds which succumb while held in quarantine. Present regulations permit the prompt release of all birds of a consignment provided no deaths are noted in the flock for 2 weeks. On the other hand, it has been fully appreciated that apparently healthy birds may be active or potential shedders of virus. Under the circumstances, it has recently become customary to destroy the entire shipment. Valuable and expensive birds, which on autopsy proved to be free from psittacosis, were thus sacrificed unnecessarily since no methods had been available to segregate the infected from the non-infected. Experiments recently conducted on a shipment of Australian parrots indicate that the complement-fixation test may detect carrier birds with a high degree of certainty.
The complement-fixation tests for psittacosis, originally introduced by Bedson 4 and proven invaluable in the early diagnosis of human infections has been adopted with certain modifications for the examination of parrots. As antigens, concentrated and trypsin-digested cultures of the psittacosis virus in Rivers-Li media have been employed. The preparation of these antigens is briefly as follows: To a medium consisting of 42.5 cc of Tyrode solution and 2.5 cc of chick embryonic tissue fragments (5 cc Tyrode solution to each 11th-day decapitated chick embryo) are added 5 cc of passage-culture, held in 250 cc Erlenmeyer flasks, cotton-plugged and sealed during incubation with “parafilm”.
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