66 Atlantic African, American, and European Backgrounds to Contact, Commerce, and Enslavementsickle-shaped. Th e result is poor cell function and ane-
mia caused by an abnormal type of hemoglobin referred
to as hemoglobin S. Th is genetically aberrant hemoglobin
evolved in Africa as a protective device against malaria
outbreaks and is known as the sickle cell trait. Th e condi-
tion produces blood clots that cause recurrent pain known
as sickle cell pain crises. Sickle cell disease can be a seri-
ous danger over time when frequent crises damage many
bodily systems.
At present only bone marrow transplants off er a cure
for sickle cell anemia. However, transplants are diffi cult.
Drugs such as hydroxyurea, introduced in the 1990s, off er
better management and can prevent complications.
Approximately 1 out of 12 African Americans has the
sickle cell trait, a trait also found in other ethnic groups
exposed over time to malarial conditions. A further 1 out
of 500 African Americans are aff ected by actual sickle cell
disease. Th e fi rst description of sickle cell disease was by Dr.
James B. Herrick of Chicago in 1910, following his treat-
ment of a West Indian patient whose anemia was character-
ized by unusual red cells.
See also: Atlantic Slave Trade; Chesapeake Colonies; Gulf of
Guinea; HispaniolaTh eodore W. EversoleBibliography
Bloom, Miriam. Understanding Sickle Cell Disease. Jackson: Uni-
versity Press of Mississippi, 1995.
Boland, Peter B., et al. Malaria Control during Mass Population
Movements and Natural Disasters. Washington, D.C.: Na-
tional Academies Press, 2002.
Desowitz, Robert S. Th e Malaria Capers: More Tales of Parasites,
People-Research and Reality. New York: W. W. Norton, 1993.
Honigsbaum, Mark. Th e Fever Trail: Malaria, the Mosquito and
the Quest for Quinine. New York: Macmillan Press, 2001.
Serjeant, Graham R., and Serjeant, Beryl E., eds. Sickle Cell Dis-
ease. Oxford, UK: Oxford University Press, 2001.Mali
Th e second great Sahelian kingdom was that of Mali. Th e
Sahel is the savannah region south of the Sahara, which,
aft er 750, became the center of culturally and politically dy-
namic cities and kingdoms because of the strategic impor-
tance of the Sahel for trade across north Africa.
Th e fi rst great Sahelian kingdom was Ghana, but the Is-
lamic revolution of the Almoravids, a Berber people livingAlthough generally seen as a tropical disease common
to second and third world developing countries, malaria is
sometimes found in developed and Northern Hemisphere
countries. Th is migration of the disease labeled “airport
malaria” is a cause for increased concern. In these instances
infected mosquitoes are transported in airplanes from en-
demic areas such as Africa and then escape to infect the
airport public, causing disease in those who have never
traveled to malaria-infected areas. Th ere is also some spec-
ulation that with global warming and globalization malaria
might become more common in areas previously thought
immune from the disease.
Th e Anopheles mosquito has been known for many
years as the transmission agent for the disease, but it was
only in 1948 that the full stages of the life cycle were un-
covered. Th e female mosquito requires blood to mature
her eggs and it is with the female that the parasite develops.
Humans provide this blood supply. Aft er biting its victim
but before actually feeding, the mosquito injects her saliva,
which contains malaria parasites called sporozoites. Th e
sporozoites enter the bloodstream and come to reside in
the human liver where they penetrate and grow rapidly. Th e
liver cells rupture and parasites known as merozoites enter
the red blood cells. Once in the red blood cells, the parasites
develop into two cycle forms, sexual and asexual.
Th e sexual cycle produces male and female gameto-
cytes that circulate in the blood and then enter the female
mosquito when it takes a blood meal from its victim. Th e
male and female gametocytes combine to form oocysts in
the wall of the mosquito’s stomach. Th ese oocysts develop
over a few days and contain large numbers of sporozoites
that take root in the mosquito’s saliva and are thus placed to
repeat the cycle of infection.
In the asexual cycle the parasites form schizonts in
the red blood cells that contain many merozoites. Aft er a
cell ruptures the merozoites are released to attack new red
blood cells.
In order to combat all types of malaria there are vari-
ous drug therapies currently in use. Th e best known was
Quinine, which was used for centuries and until the 1930s,
the only reliable treatment for the disease. Today drugs
such as Malarone, Halofantrin (Halfan), and Metfl oquine
(Larium), among others, are in common use.
A particular evolutionary off shoot of malaria that af-
fects the African American population is sickle cell dis-
ease. Th is inherited disease gained its name because the
normally disc-shaped red blood cells become crescent or