Activities Biographies Key Titles Links Literature Quiz Timeline

Deadly Organisms

Age/Grade Level or Audience

High school or college biology life science classes.

Description

Organize a study of diseases caused by fungi, protozoa, spirochetes, bacteria, and viruses carried by such organisms as the snail, rat, tsetse blood fluke, tick, louse, flea, sandfly, blackfly, and Aedes aegypti, Aedes africanus, and anopheles mosquito.

Procedure

Lead students in a study of the tropical organisms responsible these ills:

bacterial meningitis black water fever cholera dengue fever diphtheria Ebola virus encephalitis filariasis hemorrhagic fever hepatitis A

hepatitis B hookworm leishmaniasis leprosy malaria nagana onchocerciasis plague polio Q-fever

rabies schistosomiasis syphilis tetanus trachoma trypanosomiasis typhus yaws yellow fever

Show on maps the yellow fever belt of Africa and the malaria belt of Haiti, Dominican Republic, Africa, and other parts of the world. Create a time line of the resurgence and eradication of major diseases through organism control. Feature these data:

• A crippled Egyptian mummy dating to 3700 B.C. may be the world's oldest evidence of polio.
• During the fifth century B.C., Hippocrates classified varieties of malaria.
• Smallpox ravaged north Africa in A.D. 647.
• European explorers brought malaria to the Western Hemisphere in the fifteenth century.
• In the 1630s, Spanish missionaries discovered that quinine, extracted from the cinchona tree, prevented malaria.
• The Dutch first infected South Africans with smallpox in 1713.
• In 1734, John Atkins described the neurological symptoms of sleeping sickness.
• From 1764 to 1778, yellow fever surfaced in Sierra Leone and Senegal.
• The importation of African slaves to Cuba in 1803 brought sleeping sickness to the Caribbean.
• In 1822, Fever J. Campbell reported that Rhodesians inoculated healthy people with smallpox to weaken the disease.
• In the 1820s, African slaves carried yellow fever to American port cities.
• Dengue from Africa first attacked the Caribbean and coastal U.S. in 1827.
• In 1852, Bilharz discovered the microbe which causes schistosomiasis.
• In 1872, Armauer G. Hansen discovered the bacteria that cause leprosy or Hansen's disease.
• In 1880, Charles Laveran discovered that protozoa infested the blood of Algerian malaria victims.
• In the 1880s, David Bruce studied the organisms which cause tetanus, sleeping sickness, and nagana.
• From 1881 to 1882, cholera swept through Egypt.
• In 1884, Loffler isolated the diphtheria microbe.
• In 1885, Pfeiffer isolated the bacteria which cause typhus and typhoid fever.
• Nigerians first suffered sleeping sickness in 1890.
• In the 1890s, Juan Finlay hypothesized that the Aedes aegypti mosquito spread yellow fever.
• In 1898, Ronald Ross of Great Britain connected the bite of female Anopheles mosquito with transmission of malaria. That same year, Italians Amico Bignami, Giuseppe Bastianelli, and Giovanni Battista Grassi made detailed studies of how the disease develops in the human body.
• Plague invaded South Africa in 1899.
• By 1900, Dr. Walter Reed proved Juan Finlay's ideas by isolating the virus that causes yellow fever.
• In 1905, William Gorgas initiated a program of insecticide spray and draining of standing pools of water to control mosquitoes.
• From 1912 to 1946, plague killed seventy percent of the residents of French West Africa.
• A London commission studied the eradication of sleeping sickness in 1925.
• From 1925 to 1936, hygienists attempted to eradicate hookworm among South African miners.
• The mortality rate for diphtheria in Egypt in 1932 was over 45 percent.
• In 1939, Paul Miller, a Swiss chemist, created DDT to control the mosquitoes that carry malaria.
• In 1940, a yellow fever epidemic afflicted the Nuba Mountains of the Sudan.
• During World War II, more effective malaria treatments replaced quinine.
• In 1947, cholera again swept Egypt.
• By 1948, sleeping sickness was virtually eradicated in the Congo.
• In 1954, yellow fever beset Trinidad.
• In 1955, the World Health Organization (WHO) attempted to conquer malaria by spraying DDT over areas infested with mosquitoes.
• In 1959, yellow fever returned to Trinidad. Also, rifampicin is discovered as a treatment for leprosy.
• In 1961, a severe yellow fever epidemic hit Ethiopia.
• In 1965, the Rockefeller Foundation signed an agreement with the government of St. Lucia to study the control of schistosomiasis by treating the sick and eradicating the disease-bearing snail.
• An outbreak of cholera in 1971 ravaged seventeen African countries.
• In 1980, researchers studied an anti-malaria vaccine.
• By 1984, WHO declared the St. Lucia method of schistosomiasis control a success.
• In the mid-1990s, Dr. Jill Seaman fought a deadly epidemic of kala-azar or visceral leishmaniasis in remote sections of the Sudan.
• Zaire reported an Ebola outbreak in 1995.
• Throughout 1996, the Ebola virus threatened Gabon.

Sources

"CDC Travel Information," http://www.cdc.gov/travel.
Close, William T., Ebola, Ivy Books, 1995.
Dowell, William, "Rescue in Sudan," Time, Special Issue, Fall 1997, 78-82.
Hover, G. Henry, Ebola Factor, Pentland Press, 1996.

Alternative Applications

Make a similar study of Africa's most dangerous insects and reptiles, particularly the locust, scorpion, crocodile, cobra, viper, and black mamba. Determine the effects of their poisons on humans, impairment to systems, how victims are treated, and their chances of surviving attack. Note modern chemicals that ward off insects and protect swimmers from crocodiles.