Eucalyptus Hugely Successful Against Malaria for Two
Reasons

The Bill and Melinda Gates Foundation intends to finish off dreaded Malaria in the next 20 years.  One wonders if the Eucalyptus Tree will be a continuing part of the effort.

The following article has been taken from what must be the most exhaustive website on the subject of eucalyptus.  The story of Eucalyptus and its use to reduce, or in some cases eradicate, malaria reads like a mystery thriller.  I have slightly rearranged the paragraphs to increase the intrigue. 

One of the most enthralling chapters in the history of eucalyptus is its relationship to the eradication of malaria. Throughout the nineteenth century, it was believed that the eucalyptus fought malaria simply by disinfecting the ground and air. By the end of the century, the cause of malaria was found, and the eucalyptus’ true relationship to the disease became known.
  
As in any mystery there are theories. Early on there were many theories of how the eucalyptus miraculously stopped malaria. Also there were glowing accounts of real life experiences of the successes made in the fight against malaria by the eucalyptus.
 
Very few people know that California had malarial problems. Malaria could be found in the Sacramento Valley and Kern County last century. In the Third Biennial Report (1874-75) of the California State Board of Health, the secretary of the board, Dr. Thomas M. Logan, was the author of a section entitled “Malarial Fevers and Consumption in California.” Much of the report was about the eucalyptus and its ability to suppress the spread of malaria. He reprinted a contemporary article taken from the Kern County Courier reporting on one farmer’s experience with malaria and eucalyptus:

     In regard to the anti-malaria influence of the eucalyptus, we have this conclusive  evidence. We have given it what we regard as a reasonably fair test on our own farm.  This is cultivated by two families, or companies, of Chinese. One company lives near the north and the other the south end of the premises, about three-fourths of a  mile apart.
    The localities both parties inhabit are favorable to the development of malaria. The soil  is rich, moist, and teeming with vegetable life, and the free sweep of the prevailing  wind is obstructed by the intervention of dense thickets. As might be expected, they
 have, every year, during the heated term, suffered with malarial fever. Last winter  we determined to test the much vaunted virtues of the eucalyptus.
    In February we gave to the party at the north end two ounces of the seed with the  directions that it should be planted near the house. It germinated finely, and produced  several thousands of young plants, but the frost killed most of them. About twelve
 hundred, however, survived. These, when the heated term commenced, had attained an  average height of two feet, and emitted a strong aromatic or camphorous odor,  perceptible at a distance of a hundred yards.
    In due time the party at the south end were visited by their usual mildly distressing  fever, but up to the present time we have looked in vain for the first symptoms to  develop in the other. They are all, to their own astonishment, in the most robust  health. These trees now average more than three feet in height, and the atmosphere of the house is strongly impregnated with their odor . . . and propose, the coming  season, to plant it on all the waste places and corners on our farm we can spare from  the other purposes. If everybody would do likewise, the great valley of Kern County
 might soon take rank among the sanitariums of the State . . . ” 314 Concluding, Dr. Logan wrote, “These evidences go far to establish the fact that the eucalyptus globulus has a good effect in preventing the spread of malarial diseases . . . “315
 
In the California State Board Health’s Tenth Biennial Report (1886-88) appeared an article with the title “Irrigation and Forestry Considered in Connection with Malarial Diseases.” Use of eucalyptus and other plants were being used to stem the spread of malaria as seen in this excerpt:
     It is a well established fact that in malarial districts the planting of shrubs and trees  has had the effect to greatly modify, if not entirely remove, the malarious influence . . . But wonderful far efficacious than all, owing to the rapidity of its growth, its  wonderful powers as an absorbent, and the balsamic exhalation of its essential oil, it is Australian blue gum tree (Eucalyptus globulus).316
 
Dr. W.P. Gibbons of the Medical Society of the State of Californiawrote, “It has not been proved, though asserted until belief is established, that the  aroma of the eucalyptus is effective in preventing the incubation of intermittents.”317 The scientific and medical fields knew that the eucalyptus arrested malaria but didn’t really know why. The assumption by some was it was disinfected the air.
 
There were numerous reports worldwide of the success the eucalyptus was having in treating malaria. In 1874, the periodical California Horticulturalist contained such reports. For example in Cape Colony in southern Africa came this testimony: “In the spring of 1867, I planted upon this farm 13,000 plants of the Eucalyptus globulus. In July of that year, the season in which the fevers appear, the farmers were completely free from them . . . “318
 
Another example is this report from Constantine (Turkey) where eucalyptus had been planted: “The atmosphere is constantly charged with aromatic vapors, the farmers are no longer troubled with disease, and their children are bright with health and vigor.”319
 
M. Gimbert in 1874 made these comments before the French Academy of Sciences concerning the eucalyptus:
    A tree springing up with incredible rapidity, capable of absorbing from the soil  ten times its weight of water in twenty-four hours, and giving to the atmosphere  antiseptic camphorated emanations, should play a very important part in  improving the health of the malarious districts . . . it has the property of absorbing  directly from marshes, thus preventing fermentations which are produced, and  paralyzing the animal miasma proceeding from them which might arise from them.”320
 
During this period of time, throughout the world, the eucalyptus was labeled “fever tree”

Australia known as “almost fever free.”

because it generally stopped the spread of deadly fevers. In Valencia, Spain, eucalyptus trees had to be protected by guards to prevent leaves from being stripped off by its citizens.321 And what did the Australians think about their treasured native tree and malaria?
 
In 1876, J. Bosisto read a paper before the Royal Society of Victoria(Australia) entitled, “Is the Eucalyptus a Fever-Destroying Tree?” He opened with this statement:
     Its (eucalyptus) power to absorb considerable moisture, and to permeate the air with  its peculiar odour, led to the belief that this tree . . . exerts a beneficial influence upon  malarious districts . . . is the eucalyptus a fever-destroying tree? Or, in other words  does it tend to lessen malaria or to destroy miasmatic poison?322
 
Bosisto then tells of his investigations in Australia, commenting: “Australia on the whole may be said to be pretty free from virulent endemic or miasmatic fevers, and the latter may be said to exist only as the eucalyptus recedes.”323
 
After analyzing eucalyptus oils and resins, Bosisto was not able to find anything in them that had the power to oxygenate and purify the air more so than other plants.324 He noted that eucalyptus oils permeating the air, did refresh one’s breathing.325 Bosisto concludes his paper with some support of the eucalyptus’ value in fighting malaria, but the question is still virtually unanswered. He wrote, “In conclusion, may we not say with some authority that the evidence set forth in this paper on our own vegetation is in favour of the eucalyptus being a fever-destroying tree?”326
 
The most famous case concerning eucalyptus treatment of malaria comes from the Tre Fontaine Monastery near Rome, Italy. Each year during the “fever season,” the monks would come down with malaria. Swamps were near, and the monks worked the fields returning to the monastery at night. It was thought that the night air carried malaria. Eucalyptus trees were planted in the swamps reclaiming the land with their ability to drain the water through their root systems. With the water gone the mosquitoes had no habitat in which to breed and carry on activity. Malaria fever greatly lessened, but a Dr. Montechiare, who was a physician for years in that area, was not convinced that eucalyptus affected the disposition of malaria.327
 
Scientists and physicians knew that the eucalyptus did something to interfere with the process of malaria, but what it did and how it did it wasn’t clear. Many simply disclaimed it until the cause of malaria was found.
 
In California, malaria reached its peak in the 1880’s. Blue gums were planted with fervor because it was generally felt they purified the air and had some effect on malaria. This comes from the Pacific Rural Press:
     A paper read before the California Academy of Natural Sciences in 1879 reported that  the Southern Pacific Railroad had planted 1,000 eucalyptus trees between the train  stations and the marshes to ward off malaria in the interior valley.  The number of  malaria cases had dropped from twenty-five to eight.329
 
It was thought that malaria came from moist, rich soil escaping into the night air during the summer months. Night air is usually damp and chilly, and thought to carry a multitude of maladies of which one was malaria. The word “malaria” in Latin means “bad  air.”  By virtue of its aroma, it would be only natural to suppose that the eucalyptus somehow purified the “mal aria” or bad air.
 
It was also thought that the oils dropping from the eucalyptus leaves and the gums secreted from the bark, disinfected the ground around the tree. These secretions had a purifying effect just like its aroma did to the surrounding air.
 
In his 1895 work, Eucalyptus, Abbott Kinney gave many examples of the success eucalyptus was having in arresting malarial fever. Some of have been noted above. Kinney thought that malaria entered the body through the ingestion of water, milk, or food. The malarial germ, he felt, was released into the air by turning over soil in warm, marshy land, and some way it got into what humans ate or drank. He cited Bakersfield cases where unboiled water from shallow wells (he felt) caused malaria. He called it the “Bakersfield Fever.” After the water was boiled from these wells the malaria disappeared he reported.330 Kinney did experiments with meat, water, and eucalyptus leaves. He wanted to see if eucalyptus stopped the growth of bacteria. In results were inconclusive.331
 
The connection was beginning to be seen between disease and insects especially mosquitoes. Kinney used an eucalyptus smudge to kill mosquitoes, but it didn’t work.332 The Pacific Rural Press reported in 1876, ” . . . being very much in his sleep by mosquitoes, took it into his head to place a young plant of eucalyptus in his bedroom over night. From that moment the insects disappeared and he slept in comfort.”333 There was a doctor who rubbed eucalyptus leaves on his horse to drive the insects away. Pillows were sprinkled with an eucalyptus powder to keep insects off them.334
 
The Tulare Register ran this testimony: “Our house was surrounded with blue gum trees. We always slept with our doors and windows open and were never seriously bothered while just a few rods away the stock would be covered and almost perish with the great numbers (mosquitoes) tormenting them.”335
 
Finally the cause of malaria was known. In a 1900 issue of The Forester, published by the American Forestry Association, there was an article entitled, “The Eucalyptus in the Tropics: Its Rapid Growth and Value as a Sanitary Agent, Acting as a Preventative of Malaria.” It told of the cause of malaria, and urged the planting of eucalyptus to dry up swampland thereby removing the mosquito’s breeding habitat. The article went on to discuss the positive effect eucalyptus had on the air.336 This theme could be seen too in the 1897 yearbook of the U.S. Department of Agriculture:

The female anopheles mosquito carries the malaria parasite and implants it in a human’s blood system. The mosquito’s home and breeding ground is generally in a area of standing water such as swampland. Because the eucalyptus absorbs large amounts of water, it can drain swampland thereby destroying the habitat of the mosquito, and consequently stopping the spread of malaria.

With regard to the sanitary value of the tree, it has been strongly stated that its value  was owing to its rapid growth and the great absorbent power of its roots in drying up  wet and marsh lands, but it is no longer doubted that Eucalyptus globulus, along with  other species of Eucalyptus, evaporate with water a volatile oil and a volatile acid,  which permeate the atmosphere and contribute to its invigorating and healthy nature and character.337
 
The eucalyptus had found its place as a partner in the prevention of malaria, and it still held its usual stature as an agent in cleansing the air. The latter would last until modern medicine got more sophisticated and became disinterested in old-fashion ideas of treatment or “sanitation.” 

 In 2013, Eucalyptus has become one of the most important plants on the face of the planet.  The many uses of this tree and its gum, leaves, and wood, has turned eucalyptus into a major cash crop in countries all over the world.

And even with all the science that has been done, it is still not clear today why and how eucalyptus is so effective in helping reduce symptoms of and even curing everything from cold sores to aching feet.  As with so many essential oil based “cures,” the evidence of success is in the testimony of the users and the wide spread use based on those testimonies.