Use of Hamster (Cricetus auratus) for Detection of Influenza Virus in Throat Washings. ∗

One of us has reported 1 that the hamster (Cricetus auratus) gave a specific immune response following intranasal inoculation of throat-washings taken from persons acutely ill with influenza A. These observations have now been extended, not only with regard to the immune response of the hamster but also as to its use in adapting influenza A virus to mice.

Experimental Material. The throat-washings used in these experiments were collected from persons presumably ill from influenza during the epidemic which occurred in the Argentine in July, 1940. The throat-washings were taken with 20 cc of an equal mixture of 0.85 fo NaCl and buffered broth (pH 7.4). They had been preserved for a period of 6 to 8 months at a temperature of approximately −75°C in a thermos or cold cabinet 2 containing CO₂ ice.

For the purpose of serological diagnosis, acute and convalescent blood samples were taken from each person from whom a throat-washing was secured.

Method. Inoculation. The hamsters were inoculated intranasally with 0.4 cc of throat-washings while under light ether-anesthesia. As it had been shown that the intranasal instillation of a bland fluid would increase the quantity of virus in the lungs of mice which had previously received a sublethal dose of influenza A virus, 3 the hamsters were again placed under light ether-anesthesia 2 to 3 days after the inoculation of the throat-washings, and 0.4 cc of 0.85% NaCl solution was instilled into the nose.

The ferrets used for comparison were similarly inoculated with 1 cc of the throat-washings. No second instillation was given to these animals.

From animals used for testing the immune response, a blood sample was taken by cardiac puncture preceding and 2 weeks following inoculation.