This document discusses several protozoan parasites that can cause human disease. It describes the life cycles, transmission, symptoms, diagnosis, and treatment of Giardia lamblia, Plasmodium species (which cause malaria), and Toxoplasma gondii. Key points include: - Giardia lamblia causes giardiasis through ingestion of cysts in contaminated food or water which then transform into trophozoites in the intestines. Symptoms include diarrhea and abdominal pain. - Plasmodium parasites spread through mosquito bites and cause malaria, infecting red blood cells. Malaria symptoms include fever, fatigue and anemia. It is a major global infectious disease killer

1. :
PROTOZOANS AND HUMAM
DISEASE
BY KOMAL GUL

2. 2:Giardia Protozoa
 Giardia Lamblia, or Giardia duodenalis or Giardia intestinalis.
 Giardia are flagellate protozoa that cause giardiasis
 Lifecycle: The Giardia parasite exists in two forms: dominant (active trophozoite) and the inactive cyst.
The active trophozoite sticks to the intestinal lining using a hook-like ‘sucker’ responsible for causing symptoms of
giardiasis. Although active, the trophozoite cannot live outside of the human body for long, therefore it confines itself
in a hard-shelled cyst. This inactive cyst, on the other hand, can exist for longer duration outside the body. When the
contaminated food or water is consumed, the inactive cyst becomes active and transforms itself into the disease-
causing trophozoite and starts the entire cycle.
 Mode of transmission: enter the body through food or water.
 Symptoms: Generally appear in one or two week of exposure.
Diarrhea, abdominal pain, fever, loss of appetite, vomiting, headaches.
 Diagnosis:
Tissue sample, Digestive tract examination (enteroscopy), stool samples.
 Treatments:
Metronidazole, tinidazole and nitazoxanide
 Precaution:
Avoid Water and food That Might Be Contaminated.
Clean and Disinfect

4. 3:Plasmodium Protozoa
Plasmodium protozoa cause malaria.
Malaria is mosquito born infection
Mode of transmission: The parasites are spread by a mosquito vector. Parasites enter a host’s blood through the bite of an infected
mosquito. The parasites infect the host’s red blood cells.
Four kinds of malaria parasites infect humans: Plasmodium falciparum, P. vivax, P. ovale, and P. malariae
Symptoms: fever, joint pain, anemia, and fatigue.
Occurrence: Malaria is common in tropical and subtropical climates throughout the world
common infectious diseases on the planet.
Malaria is also a very serious disease. It kills several million people each year, most of them children. A vaccine to malaria is a
possibility.
Diagnoses: examining under the microscope a drop of the patient's blood, spread out as a “blood smear” on a microscope
slide. Prior to examination, the specimen is stained (most often with the Giemsa stain)
Treatments: Chloroquine, Doxycycline, Mefloquine, Primaquine Etc.
Precautions: Taking antimalarial medication to kill the parasites and prevent becoming ill
Keeping mosquitoes from biting you, Sleeping under insecticide-treated bed nets, using insect repellent, and wearing long-sleeved
clothing if out of doors at night

6. 1.Malaria infection begins: female Anopheles mosquito bites a person, injecting Plasmodium parasites
( sporozoites) into the bloodstream.
2.sporozoites enter into the human liver.
3. sporozoites multiply asexually in the liver cells (7 to 10 days), causing no symptoms.
4. the parasites, in the form of merozoites, are released from the liver cells in vesicles, journey through the heart, and arrive in the lungs, where
they settle within lung capillaries. The vesicles eventually disintegrate, freeing the merozoites to enter the blood phase of their development.*
5.In the bloodstream, the merozoites invade red blood cells (erythrocytes) and multiply again until the cells burst. Then they invade more
erythrocytes. This cycle is repeated, causing parasites break free and invade blood cells.
6.Some of the infected blood cells leave the cycle of asexual multiplication. Instead of replicating, the merozoites in these cells develop into sexual
forms of the parasite, called gametocytes, that circulate in the blood stream.
7.When a mosquito bites an infected human, it ingests the gametocytes, which develop further into mature sex cells called gametes.
8.The fertilized female gametes develop into actively moving ookinetes that burrow through the mosquito's midgut wall and form oocysts on the
exterior surface.
9.Inside the oocyst, thousands of active sporozoites develop. The oocyst eventually bursts, releasing sporozoites into the body cavity that travel to
the mosquito's salivary glands.
10.The cycle of human infection begins again when the mosquito bites another person.
Life cycle of Malaria

7. 4: Toxoplasmosis
caused by a single-celled parasite called Toxoplasma gondii.
Occurrence:
found throughout the world( more than 40 million people in the United States may be infected )
persist for long periods of time in the bodies of humans (and other animals), possibly even for a
lifetime.
A Toxoplasma infection occurs by one of the following:
•Eating undercooked, contaminated meat (especially pork, lamb, and venison) or shellfish (for
example, oysters, clams or mussels).
•Drinking water contaminated with Toxoplasma gondii.
•Mother-to-child (congenital) transmission.
•Receiving an infected organ transplant or infected blood via transfusion, though this is rare.
Symptoms
•Fever.
•Swollen lymph nodes that may last for weeks.
•Headache.
•Muscle aches.
•Skin rash.

8. Toxoplasmosis: Zoonotic disease
weakened immune systems, HIV or cancer.
400-4000 cases annually recorded in US.
Diagnoses: Blood tests, Biopsy, Imaging: CT scan or MRI ).
Treatments:
Pyrimethamine, Sulfadiazine, Atovaquone, Clindamycin,, etc.
Precaution:
•Avoid drinking untreated water.
•Wear gloves when gardening and during any contact with soil or sand.
•Wash hands to prevent infection.
•Keep outdoor sandboxes covered.