Cholera Resurgent

The epidemic began four years ago with a savage invasion of the Philippines, and the marauding microbes steadily expanded their area of attack. Java, Sumatra, Thailand, the Indian subcontinent, all suffered high casualty rates. Cholera, a disease that had just been written off as almost conquered, was once more on the rampage.

This time trouble had come in an unexpected form. The deadly bacillus was not a familiar strain of Vibrio cholerae (or Vibrio comma, from its shape), for which a vaccine of sorts is available. Instead, it was a strain of the El Tor group of vibrios,* one which had previously confined its disease-causing activities to the Indonesian island of Celebes. Once this kind of El Tor got under way, it seemed unstoppable. It secured beachheads in South Korea, Taiwan, Red China and Burma. Last year it reached South Viet Nam and Japan. Then it spread into Iran and Uzbekistan. By last August it had climbed the Himalayan foothills into Nepal. It is probably only a matter of time, say worried epidemiologists, before an infected airborne traveler takes El Tor on a jet-propelled trip to the West.

Tougher & Faster. El Tor, long underestimated, is now bullying "classical" cholera off the map. In the British Medical Journal, Calcutta's Dr. Sachimohan Mukerjee reports evidence that if old-fashioned cholera and El Tor bacilli are put into the same test tube or invade the same human victim, El Tor will completely crowd out the "classical" vibrios. Not only is it a tougher bug; it also spreads faster. And a recovered El Tor victim may remain a menace by continuing to excrete the bacilli for as long as six months, as against a mere three weeks after classical cholera.

Complete prevention of cholera by cleaning up or isolating contaminated water supplies--a more effective method of prevention than the wearing of fantastic anti-cholera costumes with a windmill on the hat (see cut]--no longer seems feasible. El Tor bacilli have spread too far, over millions of square miles. Vaccination would seem to be the next best step, but after 80 years experts still cannot agree on how good the vaccines are, or how to make the best one. Though injections of killed bacilli, as in the vaccines now generally used, stimulate the production of antibody in the blood, they seem to have little effect on multiplication of bacilli in the small bowel, where they do their damage before being excreted to infect a new host. Dr. Mukerjee is working on a vaccine made from live but harm less varieties of El Tor, which would be taken by mouth and would, he believes, protect the bowel.

At the International Congress of Military Medicine in Bangkok last month, Dr. Richard A. Finkelstein of the SEATO Medical Research Laboratory suggested that it might be possible to make another type of vaccine. This would work against a chemical poison produced by cholera bacilli that seem to trigger the damage in the intestinal wall. This impairment in turn cause cholera's devastating symptom: the most severe diarrhea known to man, in which an adult may lose up to 15 quart a day while running little or no fever.

Even the enthusiastic vaccinators agree, however, that the vaccines currently used offer regrettably short-term protection (probably not more than six months), and that the people most likely to contract cholera are the least likely to get vaccinated.

U.S. military medics are considering an attempt to develop an El Tor vaccine, but the need for it in U.S. forces is not clearly defined. Although El Tor is now established among the civilians of South Viet Nam, there has not been a single case among U.S. forces. This relative safety comes partly from luck, the medics concede, and partly from the fact that the old-fashioned vaccine they are now using seems to confer some protection against El Tor. The most important reason, say the doctors, is that cholera, like smallpox, rarely takes hold unless its victim is debilitated.

Plasma to Gut. At the Naval Medical Research Unit No. 2 ("Namru-2") in Taipei, Dr. Robert Allan Phillips, the world's most famed cholera fighter, has pursued his interest in the disease since 1955. An important development was his theory that the diarrhea results from a disturbance of what doctors call "the sodium pump." Normally, Dr. Phillips explains, sodium salts and other electrolytes pass in both directions from the inside of the bowel into the blood plasma, and vice versa; and in healthy people the movement is greater from the gut to the plasma. In cholera, the proportions are reversed. But is this because one goes up, or the other down, or both? Experiments with himself and his teammates as subjects heroically submitting to an induced diarrhea similar to that of cholera have failed to yield a definite answer. But Dr. Phillips, 59, is not giving up. Just retired From the Navy, he moved last week to Dacca in East Pakistan, where he will head the Pakistan-SEATO Cholera Research Laboratory.

The drastic reduction in recent years in the death rate from cholera has resulted mainly from the method that Dr. Phillips' team has devised to maintain the victims' balance of fluids and those all-important electrolytes, the salts of sodium and potassium. But even that Battle is not yet won. Johns Hopkins' Dr. Craig K. Wallace told the International Congress of Pediatrics in Tokyo hat the death rate is almost seven times as high among children under nine as among adults, because their fluid loss is proportionately greater.

Cholera in 1965 is a far more complex problem than medical men expected it to be. And with El Tor taking over, the oldest plague is becoming one the newest.

*Named for a Gulf of Suez port (through which pilgrims pass on the way to Mecca) where a harmless variety of vibrio was first found. Only later was the virulent form of El Tor found in Celebes.

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