Why Are Mosquitoes So Dangerous, Passport Health

Why Mosquitoes Are The Most Dangerous Creature

When considering “the most dangerous animal in the world,” there are several obvious candidates, like the Great White Shark or the Hippopotomus? But, this title rests with an animal you’d least expect – the mosquito.

Mosquitoes are infamous. They have quite a reputation for ruining barbecues and birthday parties. But the most dangerous in the world? What is it that makes them so deadly?

Though tiny, these insects cause more deaths than any other animal on the planet. Not necessarily the mosquito itself, but the number of serious diseases it could carry.

Understanding more about mosquitoes and how they spread disease is important. It helps increase awareness of the dangers of mosquitoes and provides us with the knowledge we need to protect ourselves.

What happens when a mosquito bites?

Only female mosquitoes bite and suck blood, because the blood provides nutrients for their eggs. When a mosquito lands, it punctures the skin with two tubes, one draws blood, the other injects an enzyme to help prevent blood clotting. Most people have a minor allergy to this enzyme, which creates the small bump and itching.

Mosquitoes find their victims by detecting infrared radiation emitted by the warm blood inside of us, observing our movements, and using chemical signals. They also like smelly feet.

How do mosquitoes spread diseases?

Mosquitoes suck blood, like little vampires. We, as humans, take extreme precautions when possibly coming in contact with the blood of an infected person. But, mosquitoes can carry an infection to humans or animals without regulation or boundary.

Though there are over 3,000 species of mosquito, only a couple hundred feed on human blood, and then even further, there are three main species responsible for the transmission of human disease.

Mosquitoes spread diseases in a few ways. In general, the mosquito picks up the virus or fungi when it lands and bites. The mosquito then acts as a vehicle for the virus. The virus is even able to reproduce inside of the mosquito.

When the mosquito bites again, it transfers the virus through its saliva to the victim. In the case of malaria, a parasite will attach to the gut of a female mosquito and then enter a human or animal as she feeds.

Mosquitoes can travel up to a few miles carrying their “blood meals.” One breed, salt marsh mosquitoes, can travel up to 100 miles. As mosquitoes travel from one place to another, they carry diseases with them.

Mosquito and human movement is at fault for transmitting uncommon diseases to new places. Climate change also contributes, as changing climates push mosquitoes into new, more suitable, areas.

Diseases transmitted by mosquitoes:

Disease Vaccine?

Yellow Fever Available Japanese Encephalitis Available Malaria In Development, Pills Available Dengue Fever In Development Zika Virus In Development West Nile Virus No Vaccine

Protect yourself against mosquitoes!

The CDC recommends individuals do the following to avoid mosquito-borne diseases:

    Use DEET– This repellent is the best way to protect against mosquitoes. A product containing 10% DEET can protect for up to 90 minutes before reapplication is needed.

Wear the right clothing– Wear light colored clothes. Mosquitoes are more attracted to dark colors. Be sure your clothing covers as much skin as possible to avoid mosquito bites.

  • Avoid standing water– Try to avoid areas with ponds or other standing water where mosquitoes may breed. Get rid of as much standing water as possible around your house. Mosquitoes need water to breed and live. Some species can even breed in puddles after rainstorms if necessary.
  • Do you have questions about mosquitoes or are you wondering if you are at risk for Zika on your next adventure? Set up an appointment with a Passport Travel Health Specialist by calling or booking online now.

    How do you avoid mosquitoes and mosquito-borne diseases? Feel free to comment below or contact us on Facebook or via Twitter!

    Written for Passport Health by Adrienne St. Clair


    Ysabella Minelli says

    It was really nice how you explained that mosquitoes pick up virus and fungi when it lands then serves as the carrier that spreads diseases in a matter of days. That’s the reason why I do not like knowing that we have a lot of mosquitoes in the house. My younger brother was lucky to have survived a disease that those pests carry, I’m not prepared to face the same problem again. I need to hire a pest control company to get rid of them right away. Thank you for the article.

    that’s said im glad he survived it have a bless future hope god bless yall with more happyness.

    one thing why mosquitoes are bad for you and the reason why.

    I am doing this for my genus hour thx

    Ron Booker says

    It caught my attention when you said that mosquitoes could transmit diseases. My brother got his pool installed last year, and this year he noticed a lot of mosquitoes inhabiting near his pool. I better warn him so he can reach out to an exterminator and get rid of them fast.

    Leave a Reply Cancel reply

    Do you need your passport or visa in a hurry?

    Get your travel
    documents ASAP!

    Why Use a Travel Medicine Specialist?

    We Can Answer

    • Which vaccines are required?
    • Which vaccines may be recommended?
    • Which medications do I need?
    • What Travel Supplies do I need?

    Do you need travel vaccines?

    Latest health alerts for international travelers

    INFLUENZA Worldwide
    June ’19 – According to the CDC, annual vaccination against seasonal influenza is recommended for .

    YELLOW FEVER in Argentina, Brazil, Congo, Republic of the, Nigeria, Peru, Suriname, Uganda
    June ’19 — Case numbers for yellow fever are thought to be greatly under-reported; the World Health.


    The Sneak-Attack Mosquito

    The bug at the center of the Zika outbreak, Aedes aegypti, loves humans, hides under beds, and can breed practically anywhere.

    Aedes aegypti mosquitoes are seen a laboratory in Campinas, Brazil. Paulo Whitaker / Reuters

    All it takes is a little bit of water and a warm breeze.

    Aedes aegypti, the main mosquito species that transmits Zika virus and several other serious diseases, can breed practically anywhere. These mosquitoes will lay eggs in the stagnant water collected in bird baths or old tires, sure, but also in the few droplets gathered in a discarded candy wrapper, or on the damp surface of a fallen leaf, or in a practically-empty soda can.

    This startling resilience is part of what makes Aedes aegypti so efficient a vector and, in turn, so serious a threat to humans. Zika was for decades considered to be a mild virus, mostly just a nuisance, but is now known to cause serious health problems including grave outcomes for fetuses like abnormally small heads, severe brain defects, and even death.

    In Brazil, Aedes aegypti is at the center of a Zika outbreak that global-health officials estimate will cause more than 2,500 cases of microcephaly. (As of March 22, the World Health Organization said 863 cases of the birth defect had been traced back to Zika infections in Brazil.)

    The mosquitoes responsible for spreading Zika are a formidable foe. Each female mosquito can lay about 1,000 eggs in her short lifetime, and she can lay eggs just about anywhere there’s a bit of moisture and warm enough temperatures. Eggs laid on dry surfaces can survive for more than a year, and will wait to hatch until they get wet. Once that happens, if it’s still too cool out for the baby mosquitoes, they can stay in the larval phase for many months more, as long as they have enough water to stay submerged.

    Aedes aegypti thrive in crowded cities. They’re known for their sneak attacks—biting people from behind and targeting elbows and ankles, areas where they’re least likely to get swatted away, according to the WHO. They love people, but they aren’t crazy about animals. Meaning, if you live in a place where Aedes aegypti flourish, you are what they want to eat. You and all your friends, that is.

    Aedes aegypti are known as sip-feeders because they like to take little glugs of blood from different sources, a practice that increases the likelihood that any single mosquito will transmit disease to multiple people. If they can get into your house, all the better for them. Aedes aegypti like being indoors. They hang out in closets, under beds, and behind washing machines; often emerging around dawn and dusk for blood meals from people who usually won’t even notice they’ve been bitten until it’s too late.

    “All of these features make Aedes aegypti populations extremely difficult to control,” the World Health Organization says. “They also make the diseases they spread a much larger menace.”

    If there is any good news to be found amid the threat of a Zika outbreak in the United States, it’s that an epidemic is not inevitable. So far, there have been no cases of locally transmitted Zika in the U.S.; all 388 cases of Zika recorded by the Centers for Disease Control and Prevention were brought back to the U.S. by people who had traveled to places where mosquitoes are transmitting the virus. Then again, mosquito season is just getting started. And the true scope of the public-health threat in the States is unknown.

    That’s in part because the population of Aedes aegypti may extend much farther north than scientists originally thought. Cities in South Florida and along the Gulf Coast, as well as some areas of Arizona and California, are already known to host large Aedes aegypti populations, and researchers have identified at least 50 metro areas with meteorological conditions that are ideal for the species. But even beyond those areas, the CDC has revised one map to extend the distribution of Aedes aegypti, which in recent years has been found in pockets of Washington, D.C., New York, and even New England.

    There’s also the question of the extent to which other mosquito species will be Zika vectors. Aedes albopictus, also known as the Asian tiger mosquito, is even more abundant in the United States than Aedes aegypti. In fact, many entomologists believe the tiger mosquito is quickly replacing Aedes aegypti. (However, one study found the two species often seem to co-exist just fine.)

    “But most people believe Aedes albopictus won’t be as efficient [a vector] as Aedes aegypti, because it also feeds on other mammals and birds,” said Peter Hotez, the dean of the National School of Tropical Medicine at Baylor College of Medicine. In other words, if the tiger mosquito is getting a good portion of its blood meals from horses and dogs, that means fewer opportunities for infected mosquitoes to spread disease among humans.

    More concerning than the Asian tiger mosquito, Hotez told me, is the possibility that Culex mosquitoes might become effective vectors of Zika in the United States. The distribution of this genus, which is also a vector for West Nile virus, is extensive in the United States, even in cooler regions. Preliminary research has indicated that transmission among Culex mosquitoes is possible in a lab setting, but more study is necessary.

    “Transmission of Zika through Culex mosquitos may be possible,” Hotez said. “If that turns out to be the case, then we’re all totally screwed. There are massive numbers of them already. They’re so much more widespread.”

    Already, public-health officials are warning about a significant uptick in Zika cases in the months to come. Marie-Paule Kieny, the assistant director of the WHO, said in a press conference on Monday that a combination of local transmission and sexual transmission of the virus poses the risk of a “global emergency.”


    What Good Are Mosquitoes?

    The Important Roles Mosquitoes Play in Our World

    Clouds Hill Imaging Ltd./Getty Images

    • B.A., Political Science, Rutgers University

    Not much love is lost between people and mosquitoes. If insects can be credited with evil intent, mosquitoes seem determined to wipe out the human race. As carriers of deadly diseases, mosquitoes are the deadliest insect on Earth. Each year, hundreds of thousands of people die from malaria, dengue fever, and yellow fever after being bitten by a disease-carrying, blood-sucking mosquito. The Zika virus can harm fetuses if a pregnant woman gets bitten, and chikungunya can cause debilitating joint pain. If these diseases affect a large population at once, the outbreak can overwhelm local health care, the UN reports. Mosquitoes also carry diseases that pose serious threats to livestock and pets.

    At the very least, these bloodthirsty insects are major annoyances, biting humans with a persistence that can be maddening. Knowing this, is there an intrinsic value to keeping them around? If we could, should we just eradicate them all off the face of the earth?

    The answer is mosquitoes do have value. Scientists are divided as to whether they’re worth it, though.

    The Long History of Mosquitoes on Earth

    Mosquitoes populated this planet long before man. The oldest mosquito fossils date back some 200 million years, to the Cretaceous period.

    More than 3,500 species of mosquitoes have already been described from various parts of the world, of which only a few hundred species bite or bother humans. In fact, only female mosquitoes bite humans. Males lack the parts to penetrate human skin.


    Many scientists agree that mosquitoes present more of a hassle than they have value. The mere fact that they are the reason for so many human deaths a year is reason enough to wipe them off the planet.

    However, mosquitoes serve important functions in numerous ecosystems, serving as food for many species, helping filter detritus for plant life to thrive, pollinating flowers, and even affecting the herding paths of caribou in the tundra. Last, scientists are looking at the mosquito for potential medical treatments.

    The Food Web

    Mosquito larvae are aquatic insects and, as such, play an important role in the aquatic food chain. According to Dr. Gilbert Waldbauer in «The Handy Bug Answer Book,» Mosquito larvae are filter feeders that strain tiny organic particles such as unicellular algae from the water and convert them to the tissues of their own bodies, which are, in turn, eaten by fish. Mosquito larvae are, in essence, nutrient-packed snacks for fish and other aquatic animals.

    In addition, while species of mosquitoes eat the carcasses of insects that drown in the water, the mosquito larvae feed on the waste products, making nutrients such as nitrogen available for the plant community to thrive. Thus, the elimination of those mosquitoes might affect plant growth in those areas.

    A mosquito’s role on the bottom of the food chain does not end at the larval stage. As adults, mosquitoes serve as equally nutritious meals for birds, bats, and spiders.

    Mosquitoes seem to represent a considerable biomass of food for wildlife on the lower rungs of the food chain. Mosquito extinction, if it is achievable, could have an adverse effect on the ecosystem. However, many scientists suggest that the ecosystem could eventually rebound and another species could take its place in the system.

    Acting as Pollinators

    Only the females of some mosquito species need a meal of blood to get the proteins necessary to lay eggs. For the most part, male and female adult mosquitoes depend on nectar for energy. While retrieving nectar, mosquitoes pollinate plants to help to ensure that different types of plant life thrive. When mosquitoes pollinate plants, especially the aquatic ones around which they spend much of their lives, they help perpetuate these plants. These plants provide cover and shelter for other animals and organisms.

    Medicinal Lessons?

    Although the mosquito has been a known vector for spreading disease all over the world, there is some hope that mosquito saliva may have some potential use for the treatment of the No. 1 worldwide killer of humans: cardiovascular disease. One promising application is the development of anticlotting drugs, such as clotting inhibitors and capillary dilators.

    The composition of mosquito saliva is relatively simple, as it usually contains fewer than 20 dominant proteins. Despite the great strides in knowledge of these molecules and their role in blood feeding, scientists still know only about half of the molecules found in the insect’s saliva.


    Plates from mosquitoes: harm to humans, what are dangerous to health?

    Mosquitoes, DDT, and Human Health

    A leading entomologist describes the death and suffering caused by insect-borne diseases, and tells why we must bring back DDT.

    (Excerpts of text from Fall 2002 issue of 21st Century)

    by J. Gordon Edwards, Ph.D.

    Links to other related articles:

    Anopheles, the mosquito that carries malaria, which today kills 2 to 3 million people a year.
    ( Pan American Health Organization/World Health Organization )

    See also:  National Infection Prevention and Control Manual: A-Z Pathogens

    During the war in Eur ope, in 1944, we went to sleep every night while being fed upon by bedbugs and fleas, and there was no way to escape them. We had heard about “cooties” (body lice) causing typhus, which killed more than 3 million people in Europe and vicinity during and after World War I.

    One day, I was ordered to dust every soldier in our company with an insecticidal powder that had just been received. For two weeks I dusted the insecticide on soldiers and civilians, breathing the fog of white dust for several hours each day. The body lice were killed, and the DDT persisted long enough to kill young lice when they emerged from the eggs.

    Fortunately, no human beings have ever been harmed by DDT. I later learned that the material was produced by a German chemist, Othmar Zeidler, in 1874. He had made hundreds of chemical compounds but he never suggested uses for any of them. Sixty years later, in Switzerland in 1939, Dr. Paul Müller was seeking chemicals that might kill insect pests, and he followed Zeidler’s written directions for preparing several compounds. One of them was a compound that Zeidler had labelled dichlorodiphenyl-trichloroethane. Müller called it “DDT,” and in 1948, he received the Nobel Prize for his work with that chemical.

    Dr. Joseph Jacobs later described his role in producing the first DDT made in the United States. At Merck & Company in New Jersey, he was assigned the task of duplicating Zeidler’s procedure, but on a much larger scale. He commandeered a huge glass-lined reactor, and produced the first 500 pounds of DDT made in the United States. An Army truck rushed it to an airport, and it was flown to Italy, where it halted a developing epidemic of typhus in our troops. The Surgeon General telegrammed thanks from President Roosevelt, and stating: “It is estimated that 5,000 lives were probably saved by destroying the typhus-carrying body lice infesting our soldiers.” 1

    See also:  Bed Bug Bites: The Truth about Bed Bugs and Your Health – PestWorld

    After the war, I entered Ohio State University to study entomology. Insects are the most abundant forms of life on Earth; fortunately, only about 1 percent of them compete with human beings for food, fiber, and space. A small part of that 1 percent threatens our health with stings or bites, and a few transmit serious diseases.

    I received my Ph.D. for research on beetles, and was hired to teach entomology at San Jose State University in California. There I spent much time studying parasitic insects, and taught medical entomology courses for more than 30 years. In addition to louse-borne typhus, our students were required to learn about diseases caused by mites, ticks, fleas, kissing bugs, black flies, chiggers, sand flies, eye gnats, tsetse flies, and mosquitoes.

    DDT has saved more millions of lives than any other man-made chemical.
    ( Courtesy of Gordon Edwards)

    Insect-borne Killer Diseases
    At least 80 percent of human infectious diseases are arthropod-borne—transmitted by insects, mites, or ticks. 2 They have caused the death of hundreds of millions of people by infecting them with the pathogens that cause typhus, bubonic plague, yellow fever, malaria, dengue fever, sleeping sickness, encephalitis, elephantiasis, leishmaniasis, and yaws.

    Flea-borne Diseases
    Typhus. In Europe there have been more than 150 typhus epidemics. During the Thirty Years’ War, typhus reduced the population from 30 million to just 13 million, killing 14 times more people than died in battle.

    Scientists named the pathogen that causes typhus Rickettsia prowazeki, after two researchers who lost their lives because of their work: While studying a Mexican typhus epidemic, Howard Ricketts died of typhus three weeks after becoming ill, and Stanislas von Prowazek died of typhus in Poland.

    The Saturday Evening Post, in an August 1942 article titled “Blitz Plague,” referred to the body louse as “the mass killer which has slaughtered 200 million people in Europe and Asia alone, diverted the stream of history, and done more than any other single factor to determine the outcome of wars.” It reported:

    This year, in the Polish town of Vilna, where typhus once killed 20,000 of Napoleon’s troops retreating from Russia, railway employees were forbidden to approach trainloads of infected German soldiers returning from the Russian front. When infected, a person’s fever often reaches 107 degrees, with excruciating headaches and delirium. Mortality rates may be as high as 70 percent.

    Bubonic plague. In the 14th Century, fleas that sucked blood from sick rats ingested pathogenic bacteria that were later named Pasteurella pestis. When those fleas then bit humans, they transmitted bubonic plague to them. That plague (the “Black Death”) killed one-fourth of the population of Europe and two-thirds of the population of the British Isles.

    U.S. Department of Agriculture

    In World War II, troops and refugees were dusted with DDT powder to kill the lice that carried typhus.

    Mosquito-borne Diseases

    More than 3,000 species of mosquitoes have been described in scientific journals. Most of them are in tropical areas, where as many as 150 species have been found in a single square mile. The United States contains about 170 species, Canada 70, and Arctic lands less than two dozen. In the Canadian Arctic, researchers who bared their arms, legs, and torsos in an experiment reported as many as 9,000 bites per minute. Unprotected human beings there could lose half of their blood in two hours, and die. Hundreds of cattle and horses have been killed by just such exsanguination, in our southeastern states.

    Yellow Fever is caused by a virus transmitted by Aedes aegypti mosquitoes. Perhaps the disease was brought into America with slaves in the 1500s, but it also could have originated in monkeys in Central America, which still harbor it.

    The name of this disease refers to the yellowing of skin that results after the infected mosquito bites. After a 10-day gestation period, there is a sudden onset of fever, with aching, nausea, bleeding from digestive tract, lungs, nose, and mouth, and severe vomiting (frequently bloody). Mortality rates from yellow fever often exceed 50 percent of the cases.

    In 1542, Hernando DeSoto suffered with it and almost half of his troops died of it, in what is now the state of Florida. In 1741, England sent Admiral Edward Vernon with 27,000 men to Mexico and the Louisiana Territory. They retreated after 20,000 were killed by yellow fever. In 1802, Napoleon’s brother-in-law, Charles LeClerc, came to the Louisiana Territory with 33,000 soldiers, but gave up after 29,000 of them died of yellow fever.

    Napoleon had envisioned a French colonial empire in the New World, but after such severe losses he did an about-face and sold the Louisiana Territory to the American colonists for $15 million, nearly doubling the size of our country. Some historians say that the sale was a result of yellow fever killing 40,000 French troops.

    In 1900, in Cuba, the U.S. Yellow Fever Commission investigated the disease, under the guidance of Walter Reed, James Carroll, Jesse Lazear, and A. Agramonte. Their research with human volunteers proved that the fever was transmitted only by the bites of Aedes aegypti mosquitoes, rather than by personal contact. 3 Attempts to eradicate those mosquitoes almost succeeded in Central America and the Caribbean, but failed in southeastern United States, where Aedes aegypti still abound. Their larvae thrive in junk yards and auto wrecking yards, where they live in used tires and other small containers of water.

    Yellow fever vaccines have been available since 1942, but must be kept refrigerated. That is a problem in hot countries, especially because Freon was unwisely banned by pseudo-environmentalists in the great ozone hoax. More than 400 million people have been given the vaccine.

    In Central America a pretty native mosquito, Haemagogus spegazinii, transmits the virus from monkey to monkey in the tree tops. If a tree falls in the jungle and human beings are nearby, the Haemagogus can transmit the virus to them. These individuals may then serve as reservoirs of the fever in their villages.

    See also:  How to Get Rid of Pubic Lice? Natural Medications for Pubic Lice Treatment

    Encephalitis Viruses. Mosquitoes transmit many other kinds of viruses, causing illnesses such as Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), Japanese B Encephalitis (JBE), Venezuelan Equine Encephalitis (VEE), and West Nile Encephalitis. An epidemic of SLE in 1933 devastated St. Louis and several other cities as far east as Louisville, Ky. More than 1,000 cases there resulted in 266 deaths.

    Japanese B Encephalitis has been very deadly in Japan and Korea. In 1924, Tokyo had 6,000 cases, and 3,800 died. In 1948, Japan had 8,000 cases and 4,750 died. The vector, the Asian Tiger mosquito (Aedes albopictus), is now well established in the United States, and has already transmitted fever viruses to children in southeastern and midwestern states, and in Texas. Transovarial transmission may pass encephalitis viruses from female mosquitoes to their larvae, via infected eggs.

    Dengue Fever is also known as “Breakbone Fever” because the virus causes extreme aching of joints, even the joints between plates in the skull. Many kinds of mosquitoes transmit the virus, but Aedes aegypti is the major vector. In Guam, 98 percent of the American troops were infected. Some of my students served with the U.S. Navy and had been infected with dengue. They told me that the pain was “indescribable,” and one said: “When I had malaria I was afraid I might die, but when I had dengue I almost wished that I could die.” The only medication they had was aspirin, which gave very little relief.

    In addition to the fever and other symptoms, the dengue virus causes great pain in the eyes, “like someone has his fingers behind your eyeball and is trying to pull it out.” A first exposure to dengue is not often fatal, but re-exposures are more serious, with about 15 percent mortality caused, especially in children

    The Asian Tiger Mosquitoes, Aedes albopictus, are efficient carriers of the dengue virus. When they first invaded Brazil, there were only 6 dengue cases in Rio de Janeiro (in 1985). In just one year, the mosquitoes spread the fever to 350,000 people! In 1985, some of these mosquito larvae were shipped into Houston Texas from Japan, in old automobile tires—they can breed successfully in as little as a quarter inch of water. In Evansville, Indiana, they were also breeding in piles of old tires. The piles were sprayed with insecticides every day, for 11 days, but swarms of adult mosquitoes still emerged. In early July 2001, Tiger Mosquitoes were found in the San Francisco Bay area of California. They had just arrived from China, in a shipment of live bamboo plants. The larvae had matured in the water surrounding the plant roots. This mosquito will probably extend its range from coast to coast, and many encephalitis cases should be anticipated. . . .

    The author, featured in Esquire magazine, September 1971, eating a tablespoon of DDT, a feat he repeated publicly almost every week in his public campaign to show the safety of DDT.
    ( Courtesy of J. Gordon Edwards)

    DDT: Safe, Effective, and Inexpensive
    To control Anopheles mosquitoes, DDT was sprayed on inside walls once or twice a year. In 1959, spraymen applied 60,000 tons of DDT to the inside walls of 100 million houses. There was never any need to wear masks or protective clothing while doing DDT spraying. No adverse effects were ever experienced by the 130,000 spraymen or the 535 million people living in the sprayed houses. 8

    In house spraying, the amount applied was 2 grams of DDT per square meter of wall, every 6 months. 9 Also, no wildlife was injured by DDT in those areas. The World Health Organization Director concluded, “The discontinuation of the use of DDT would be a disaster to world health.”

    Montrose Chemical Company workers in California, who wore no masks or goggles, were never harmed by their constant exposure to DDT. When their fatty tissues were analyzed, they were found to contain up to 647 parts per million (ppm) of DDT residues. The fatty tissues of the general population at that time contained only 5 or 6 ppm of DDT. 10 There were no cancer cases in those workers, even after 1,300 man-years of heavy daily exposure to DDT. Dr. Edward R. Laws, of the U.S. Public Health Service, found that those Montrose workers still were healthy after 10 to 20 years of that exposure.

    In addition to its effectiveness, DDT is inexpensive. The cost of spraying in 1959 was $205,000, but if substitutes had to be used, malathion would have cost $637,000, and propoxur would have cost $1,762,000 for the same control. A 1.5 oz. whisky jigger full of 70 percent wettable DDT covers 144 square feet of wall surface, killing all mosquitoes that land there during the next six months.

    In the 1960s, the World Health Organization tested more than 1,300 pesticides, seeking effective substitutes for DDT in mosquito control. Only four approached DDT’s effectiveness: Malathion, Aprocarb (Baygon), fenthion, and fenitrothion, but all were more hazardous to humans than DDT and were 4 to 20 times more expensive than DDT. 11

    Because, over the years, I kept hearing propagandist claims that DDT is toxic to people, I studied all of the relevant scientific and medical literature. Here I mention only some details on DDT’s safety:

    Evidence That DDT Fights Cancer
    • Drs. Charles Salinskas and Allan E. Okey reported that DDT in rodent diets inhibited development of induced mammary cancers and leukemia. 13

    • A.E. and E.K. McLean determined that after animals had ingested DDT, the highly toxic aflatoxins they had been fed were not fatal, perhaps because they were converted to non-toxic metabolites by the liver. 14 DDT was also known to induce the formation of hepatic microsomal enzymes which, in turn, inhibited the growth of tumors and cancers.

    Dr. Wayland Hayes performed tests for the U.S. Public Health Service, feeding human volunteers up to 35 milligrams of DDT in their food every day for 18 months. (The average human intake of DDT in the United States at that time was about 0.03 mgs per day, or 0.36 mgs per year.) 15 No adverse effects resulted, either at the time of the study, or during the next 10 years.

    As a result of such studies, I felt that it was safe for me to ingest DDT. I was delivering addresses to various audiences almost every week. I carried a commercial box of DDT onto the stage, dug out a tablespoon of DDT (about 12 mgs), swallowed it, and washed it down with water before beginning my talk about DDT’s lack of toxicity to vertebrate animals. Esquire magazine, in September 1971, pictured me ingesting a tablespoon of DDT. The text explained that I had “eaten two-hundred times the normal human intake of DDT, to show it’s not as bad as people think.”

    At the same time, the pseudo-environmentalists were going wild against DDT. Clifton Curtis of the World Wildlife Fund, for example, wrote that “DDT is so potent that as long as it is used anywhere in the world, nobody is safe”—and provided no data to back up his assertion. Dr. Gilbert L. Ross, of the American Council on Science and Health, characterized Curtis’s remarks as “typical of the dangerous environmental disinformation masquerading as science that has been stirring DDT hysteria ever since the 1960s.” Ross pointed out that “Extensive scientific studies have not found any harm to humans, even during the massive overuse of DDT in agriculture in the 1950s and 60s.” Furthermore, the scientific reports show that there is no indication of DDT use harming people, birds, bird eggshells, or other vertebrate animals. 16

    During the 1960s, the World Health Organization proposed the possible eradication of malaria, worldwide, and malaria control was achieved in areas with a population of 279 million people. Thirty-six formerly malarious countries totally eradicated the disease. The U.S. National Academy of Sciences stated in 1970:

    To only a few chemicals does man owe as great a debt as to DDT. In little more than two decades DDT has prevented 500 million human deaths, due to malaria, that would otherwise have been inevitable. . . . 17


    No comments

    Добавить комментарий

    Your e-mail will not be published. All fields are required.