Question

Which of the following is a sporozoan?
A. Eimeria
B. Monocystis
C. Plasmodium
D. All of the above

Answer 1

Hint: The sporozoans are a large subphylum of unicellular parasites that live inside their host cells. Over 65,000 species of sporozoans are known with malaria-causing parasites being the common one. Most of the sporozoans cause fatal diseases in humans. All of these parasites have a complex life cycle requiring two hosts.

Complete answer: Sporozoans characterized by the absence of cilia or flagella are generally parasitic organisms that usually require vectors for their spread. They have a complicated life cycle requiring switching of two or more hosts and sexual and asexual stages. They are strictly intracellular parasites that are responsible for many human diseases. These are single-celled eukaryotic microbes. a)Eimeria is a sporozoan parasite that causes a disease named coccidiosis in cattle, dogs, cats, and poultry. They require a single host to complete their life cycle. The sporozoites of Eimeria infect the enterocytes of the small intestine and then migrate to target sites.
b) Monocystis are also sporozoans and are endoparasites found in seminal vesicles and coelom of earthworms. They also have only one host that is the earthworm. Fully grown trophozoites of Monocystis are spindle-shaped elongated cells.
c) Plasmodium is the most common known sporozoan which causes malaria in humans. It is an obligatory parasite. It has two hosts namely female Anopheles mosquito and human. They primarily infect the red blood cells of humans.
Hence, option D is the right answer.

Note: Sporozoites have a special ability to survive unfavourable environmental conditions. This is because they form a protective covering around them which makes them resistant to harsh conditions. Prevention is the key to inhibition of the spread of these sporozoans. Cleanliness and good health should be maintained.