Black Death has not lost all its grip

Press, 21 January 1984, Page 15

Black Death has not lost all its grip

By

CARLA McLaughlin,

National Geo-

.. graphic News Service * ' F

The Black Death rampaged across fourteenth-century Europe, killing a third of the population. Wagons roamed the desolate streets to the shouts of their drivers, “Bring out your dead!” The mystery disease, cause and cure unknown, was “the plague.” Today, the cause and cure of human plague are known, but the disease still remains a mystery. The complex ecology of plague and the mechanisms that can trigger an epidemic continue to baffle scientists. And 1983 saw the continuation of the sharp upsurge in the number of plague cases reported in recent years. Thirty-nine cases were reported in the United States; six of the victims died.

New Mexico had 26 cases, by far the most of any state. Four other western states, Arizona, California, Oregon, and Utah, also reported human plague. Nine states reported plague among animals. (Twenty-one cases of plague have been recorded in New Zealand since 1900; nine were fatal. With one exception — at Lyttelton in 1902 — the cases were all in Auckland. All cases in New Zealand occurred before 1912: 1900, one case; 1902, four; 1903, one; 1904, two; 1907, two; 1910, three; 1911, eight. The last eight cases were reported between March and May, 1911. No cases have been reported since then.

Among the sufferers were a wharf labourer, a worker who had unloaded a paper shipment from overseas, and two men who had removed dead rats from a Queen’s Street warehouse.) The horrifying reputation of the disease, which has lent its name to maladies having nothing to do with plague, tends to create panic. Yet the initial symptoms are often not disturbing enough. High fever, vomiting, rapid heartbeat, and swelling of lymph glands in the groin or armpits are the most common symptoms, and people who see them often misdiagnose them as influenza and leave them untreated.

Only pneumonic plague, a rare and more virulent form of the disease, can be spread by coughing. Bubonic plague, the most common type, which can be cured by antibiotics, is transmitted by flea bites. Doctors most dread the highly contagious pneumonic form, which kills more quickly. Dr Allan Barnes, director of the Plague Branch of the United States Centre for Disease Control, believes there is cause for concern, but not alarm. “The problems we have with plague now are merely individual encounters with the disease in nature and not epidemic outbreaks,’’hesays. The Plague Branch, located in Fort Collins, Colorado, monitors, analyses, and consults on plague cases in the United States and advises the World Heajth Organisa-

tion on plague in the Western Hemisphere. “Our primary objective,” says Dr Barnes, "is to develop data that will enable us to detect, and ultimately to predict, epizootic outbreaks in wild rodent populations that may lead to human exposure. Human plague in the United States results from chance encounters with infected fleas or from handling diseased animals. Since 1925, all North American plague cases have been traced to wild rodents, such as ground squirrels, and their fleas. However, other animals, including pets, have played intermediary roles by taking the infected fleas to areas where humans live.

The last urban plague epidemic in North America was in Los Angeles in 1924-25, when 34 of 38 victims died. The. eastern United States is plague free because, scientists believe, it has few com-munity-dwelling rodent species with the population density to allow the disease to thrive. The high incidence of plague in the south-west is believed to come partly from life style and partly from the types of rodents and fleas

that live there. The region’s rural and expanding suburban populations live close to communities of rodents. Many people live near the rock squirrel, which hosts a species of flea that readily bites humans. Domestic dogs roam freely and carry diseased fleas home to their owners. Dogs, however, are resistant to plague. Cats are not and, should they become ill, they can transfer plague directly to humans. A ground squirrel infected with bubonic plague was found in a Los Angeles city park in early October. Anxious health officials spread poison grain for squirrels and dusted insecticide for fleas. “Rat control programmes in both urban. and rural areas in the western United States represent the most important barrier to the recurrence of epidemic plague,” says Dr Barnes. “Other diseases come and go,” he adds, “but plague remains a naggingly important problem. Until we can spend more time and .money researching the disease, we will continue to have episodes like this one.”