Page 12 - Kingdom Protist

humans by female Anopheles mosquitoes. Malaria causes fever, chills, and other flu-

like symptoms. Its greatest impact is in tropical and subtropical regions where factors
such as high temperature, humidity, and rainfall favor the growth of mosquitoes and
sporozoans, and preventative measures are too costly.
Zoomastigina
Protozoans in the phylum Zoomastigina are called zooflagellates. Zooflagellates

are animallike protozoans that use f lagella for movement. Some zoof lagellates are
free living, but many are parasites inside other organisms.
At least three species of zoof lagellates from the genus Trypanosoma cause
infectious diseases in humans that often are fatal because of limited treatment
options. One species found in Central and South America causes Chagas disease,
sometimes called American sleeping sickness. The second species causes East African
sleeping sickness. The third species causes West African sleeping sickness.

American sleeping sickness

The zooflagellates that cause Chagas’ disease are similar to the sporozoans that
cause malaria because they have two hosts in their life cycle and insects spread the
diseases through the human population. The reduviid bug, shown in Figure 2.7, serves
as one host for the protist in Central and South America. The parasitic zooflagellates
reproduce in the gut of this insect. The reduviid bug gets its nutrients by sucking blood
from a human host. During the feeding process, the zooflagellates pass out of the
reduviid body through its feces. The zoof lagellates enter the human body through the

wound site or mucus membranes. Once the zoof lagellate enters the body, it multiplies
in the bloodstream and can damage the heart, liver, and spleen.

Figure 2.7 Tsetse fly
The insects that carry protozoans
from person to person are
controlled by insecticides.

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