EMBRYONATED EGGS

Wairarapa Times-Age, 4 June 1943, Page 4

EMBRYONATED EGGS

latest medical miracle. BIG FIELD OPENED UP. Embryonated eggs—fertile eggs—fertile eggs which have been partially incubated—are helping wartime medicine in the diagnoses and prevention of diseases of man and beast, Dr. F. R. Beaudette, poultry pathologist, New Jersey (U.S. America) Agricultural Experiment Station, told members of the New Jersey poultry industry recently. Principal practical application of the medically miraculous new uses for eggs in their “half-hatched” state is in production of human and animal vaccines in the large quantities necessary for wartime. Many of the new developments are shrouded in military secrecy, but Dr. Beaudette revealed that persons in war service receive vaccines for yellow fever and typhus which are grown on chick embryos.

“Tremendous amounts of vaccine for human influenza were produced on embryonated eggs in laboratories somewhere on our Eastern seaboard, and sent to England to immunise the population against this disease,” he told his audience.

Horses are essential in wartime for both agricultural and military purposes. One of the diseases of the horse is equine encephalomyelitis or horse brain fever. Immunisation is possible through use of a vaccine that formerly was harvested from the brains of diseased animals. However, only about three horses could be treated with the vaccine from one horse’s brain. Enough vaccine can be produced in one egg to immunise four horses because of the great concentration of virus in the egg, the poultrymen were told. In its most general and simple application, the technique requires the production of 10 to 12-day-old embryos. The normal incubation period is 21 days for hen’s eggs, hence the term “half-hatched eggs.” The shell of the embryonated egg is carefully opened to permit introduction of the pathogenic organism through the shell membrane. The opening is then sealed, and the egg returned to the incubator. Incubation continues for only a few hours for certain viruses, or for several days for others, experimentation having proved the correct period for each type. The vaccine is then harvested from the infected embryo.

Stating that the field of application had hardly been touched, Dr. Beaudette said that diagnoses of diseases as well as immunisation are a practical use to which embryonated eggs are already being put Besides viruses, many other pathogenic organisms can be cultivated in the laboratory eggs, including bacteria, Rickettsia, fungi, protozoa, and minute parasites. Positive distinction between smallpox and chicken pox is quickly and inexpensively made through differential diagnoses of embryonated eggs into which suspicious human sera are injected.