In the Eastern Province of Saudi Arabia, the malaria-spreading habits of the mosquito Anopheles stephensi have been greatly curtailed by Saudi Arab Government and Aramco medical teamwork.
Dr. Robert Peffly, Aramco entomologist, peered into the microscope and put it into focus. Then he motioned to his visitor.
"Take a look—there she is."
And, there she was—an evil little female who's been causing misery for centuries: a mosquito known as Anopheles Stephensi—better known as "Sterne."
Because of her, and about 60 other species of anopheline mosquitoes, 1,200,000,000 people in 148 countries live under constant threat of malaria. Every year, on every continent, she leaves millions of her victims weak, listless—and too often dead.
"Malaria," says the World Health Organization, "is man's most expensive disease—the world's greatest single cause of disablement."
To fight it, the World Health Organization last year launched what it calls "the greatest coordinated public health program in the world's history."
But, malaria—and Sterne—have already had their reign of terror smashed in Saudi Arabia's two great eastern oases: Qatif and al-Hasa, where more than 300,000 people make their homes.
From 1948 through 1955, the fight was waged jointly by Aramco and the Saudi Arab Government. Since then the Government has assumed the full burden, with Aramco continuing its annual surveys of infection and carrying on constant research.
Complete eradication has not been achieved but Steffie has been conquered. It's just a question of how soon she and her relatives surrender unconditionally.
Her conquest is a story of a year-after-year battle of a few men against hordes of insects—a battle that had its successes and its days and depressing ones It began in 1947, in the Qatif oasis.
Hidden there was an enemy that had held sway for hundreds of years. Early travelers called it «oasis fever» or «gulf fever»—in many a year, the area's No. 1 killer. Those who dwelled there expected many infants to die each spring and fall; they accepted chronic illness as part of oasis life
Along came a little group of men: Dr. Richard H. Daggy, now Aramco’s medical director and then a young public health practitioner, and a staff of assistants. They wanted to know how many people had malaria, so they went into the towns and villages to find out. Their samplings showed that in village after village, all infants were infected; 70 to 98 per cent of all other children examined were infected, (Examination of infants and children is the means by which malaria-infection rate is determined.)
The year 1947 was a bad one in the oases: everywhere an epidemic raged.
"So many were stricken," Dr. Daggy recalls, "that Aramco didn't have enough hospital beds for even its own employees. Beds had to be allocated arbitrarily to those with fevers of 102 or higher. The rest could only be given medication, then returned to their quarters."
Early the next year, the Government accepted Aramco's proposal for a joint program of malaria control. That fall the mosquitoes or Qatif got their first spraying with DDT.
But before the battle started against Steffie, it had to be determined just what kind of creature she was—and the term "she" is used advisedly: only the female mosquito transmits malaria.
Steffie begins as an egg, laid at night. Her birth place is in protected water that isn't too warm or too cool. Considered ideal by her parents is a drainage ditch that's clogged with grass or weeds, affording shelter against sun and larva-eating fish. Other favored breeding places are seepage areas, swamps, temporary ponds and puddles, and shallow wells.
It takes Steffie about eight days to evolve from egg to larva (or "wiggler") to pupa (or "tumbler") to full-fledged mosquito; after that, her life may last a week to a month. She has her first meal of blood during her first night after emergence from the pupa state. Thereafter, she continues to choose night time for her meals, with the most popular hour being just before midnight. And the gals enjoy getting together after dinner, when as many as 600 engorged females have been discovered clustered on a 15-square-foot wall surface.
This dinner-at-night custom, incidentally, is a boon to malaria fighters. They enter Steffie's hangouts only in daytime, when possible. If they must go in at night, they take preventive medicine. An interesting gastronomical note is that man isn't really Steffie's favorite morsel—she much prefers cattle.
She likes to be where it's warm and moist, but not too hot or too moist. Give her a choice, and she'll take it around 90° F., with about 80 per cent relative humidity. Short exposures to temperatures of 104° to 113° can kill her. That's why she spends her days resting indoors, in the palm-thatch and adobe dwellings of the oasis villages. She's fussy, though, about where she rests. If the ceiling is too warm, she'll move to or near the floor, or cluster with her friends around "sweating" jugs, or in hidden crevices.
Steffie is as harmless as can be until she meets somebody who has malaria. Only by drawing blood from such a person can she pick up the parasite that causes all the trouble. After that—if she bites someone—ten days to two weeks later, that person becomes sick.
When the spraying teams did their first work in 1948, the results were immediate and dramatic. In the Qatif Oasis, the infection rate among infants was slashed from 100 per cent to 44; among all other children, it dropped from 85 to 52 per cent.
"By 1949," Dr. Daggy relates, "the results had become spectacular. For Qatif oasis as a whole, the infection rate had dropped to 14.4 per cent; for infants, to 3.3 per cent."
These great gains were maintained during the next three years. DDT was doing just fine. And, then . .
In 1953, the number of malaria cases rose for the first time since control began. In 1954, the rate went up again. Making things worse, the man who had been the entomologist had returned to the States. Dr. Daggy had been assigned to administrative work. No one was available to dig out the reasons for the rising malaria rate.
Finally, in October, an important clue showed up. Only a few weeks after the spraying, Steffie began to reappear in treated houses—a striking contrast to 1948, when the spray's effects lasted more than a year. The obvious explanation was that Steffie had gained the ability to resist DDT.
Those were bleak days, indeed, for the anti-malaria teams. They thought they had Steffie on the ropes, but now she was making the rounds again. Furthermore, the same DDT resistance was showing up in Greece, Java, Lebanon and the United States.
With prayerful gratitude, the insect fighters saw a ray of hope. During 1954, they'd received some experimental supplies of another insecticide: dieldrin.
When Steffie began reappearing that fall in houses that had been sprayed with DDT, she did not show up in those that had been test-sprayed with dieldrin.
Optimism was great. Naturally, all during the fall of 1955, spraying was done with dieldrin. And, down went the malaria rate. Down it went again in 1956—to about one-eighth what it had been in '54. By 1957, it hit the lowest rate ever. The infant infection rate was down to zero; among other age groups in Qatif, just over 6 per cent; in al-Hasa, less than that. Dr. Daggy then reported:
«Malaria transmission had been stopped, for all practical purposes, by the end of 1957.»
Surveys in 1958 and 1959 bore him out. Control had definitely been achieved, and eradication was just around the corner—or so it seemed.
In 1960, the situation remained excellent in al-Hasa. But, in Qatif several malaria cases were reported. Not many, but enough to raise the question: "What's going on?"
Dr. Peffly thinks he may know. Dieldrin is still felling Steffie, but there's another little witch named fluviatilis.
This species had never been a major trouble maker in the two oases. She still isn't. But, any malaria-spreading is too much, and the disturbing part is that Dr. Peffly has proved in his laboratory that this mosquito sneers at dieldrin.
What, then, can be done? The answer is that it isn't necessary to destroy all mosquitoes to stamp out malaria. The parasites usually disappear from the blood of their human hosts after three years. If new infections can be prevented over that period, the transmission cycle can be permanently broken.
As for fluviatilis: although she resists the dieldrin that kills Steffie, she does yield—so far—to the DDT that Steffie ignores. It's been suggested that a "one-shot" combination of dieldrin and DDT be tried.
Also, there are other weapons: better water control to prevent overflow and seepage; larviciding of major breeding places and filling in of smaller ones; introduction of larva-eating fish; health education. And, new and better drugs for treating malaria are being developed continually.
The Ministry of Health has launched a full-scale push for eradication, in cooperation with the World Health Organization. All oasis villages are to be surveyed so that drugs may be administered to everyone found with malaria.
Once the enemy is licked, the job thereafter will be "maintenance." If it works, Steffie and Fluvie and all their relatives will find life pretty frustrating in the oases of Qatif and al-Hasa.