Page:Popular Science Monthly Volume 82.djvu/370

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have recently proved the identity of typhus and "Brill's disease" a disease fairly often seen in large cities. They have also shown the role of the body louse in transmitting typhus. The isolation period for suspects is fourteen days.

No more terrible epidemic has ever threatened this country than bubonic plague and against the entry of no disease are more rigid precautions taken. It exists constantly in oriental countries, especially in China and India, and the great danger of introduction here always confronts us. There are several forms of plague, of which the pneumonic type is the most deadly. This was the prevailing type in the recent epidemic in northern China. The bacillus of plague lives and multiplies in the blood of the victim. It also causes an epizootic in rats and certain other rodents, and from these, as well as from human cases, the bacilli are carried to human victims through the agency of fleas and bedbugs. In addition pneumonic plague is highly infectious directly, spreading from man to man by aerial convection. It is very easily seen how important is the eradication of plague epizootic among rats, ground squirrels and other rodents as is being done now in California. An epizootic is a powder magazine waiting only for the match of proper local conditions to explode in all directions in an epidemic of the greatest virulence.

Quarantine measures against plague first of all aim to prevent infected cargo, baggage or ballast from being shipped. To this end rat guards are used, all suspicious articles going on the vessel are thoroughly disinfected and special efforts are made to destroy all rats on board. Cases of plague reaching a domestic quarantine station are isolated and the surroundings and belongings thoroughly disinfected.