PROTOZOA : PROTOZOA -Reproduction- -Importance- -Pathology- Slide 2: Asexual
- characterized by division of the body into two or more parts, each of which develops into a complete individual.
- self supportive cell sprouts from & detaches from the parent organism.
- a multiple fission type; the nucleus undergoes multiple divisions before the cell divides.
- the simplest form of reproduction. Two single-celled organisms link together, exchange genetic information, & then separate. - Reproduction - Schizogony : Schizogony Slide 5: Conjugation Encystment : Encystment - Some protozoa are coated with a protective capsule called cyst. Cyst permits organism to survive when food & oxygen are lacking or when temperature is not suitable & toxic chemicals are present. Cyst : Cyst Tropozoites Slide 8: Cyst is a reproductive structure in which new cells are produced asexually.
- The breaking of cyst is called excystation. Protozoan Diseases of Digestive System : Protozoan Diseases of Digestive System 1. Giardiasis infection of the
intestine caused by
Giardia lamblia. Slide 10: Giardia lamblia is flagellated parasitic protozoan that is able to attach firmly to a human’s intestinal wall. Slide 11: Symptoms
- Characterized by malaise, weight loss, flatulence, & breath with distinctive odor of hydrogen sulfide.
- A prolonged diarrheal disease due to infection of small intestine.
- The disease is diagnosed by finding cysts in fecal smears.
Reqquired drugs are metronidazole and quinacrine hydrochloride.
Good sanitation. 2. Cyclospora Cayetanensis : 2. Cyclospora Cayetanensis A diarrheal disease caused by a parasitic
protozoan cyclospora pix Most outbreaks of the disease have been associated with the ingestion of oocyst in water, uncooked foods. : Most outbreaks of the disease have been associated with the ingestion of oocyst in water, uncooked foods. This disease is specially debilitating for immunosuppressed people. Consumed foods have been contaminated with feces. The antibiotic combination of trimethoprim & sulfamethoxasole is used for treatment. 3. Cryptosporidiasis : 3. Cryptosporidiasis Cryptosporidiosis, also known as crypto, a parasitic disease caused by Cryptosporidium. Slide 16: Protozoan parasite in the phylum Apicomplexa. It affects the intestines of mammals and is typically an acute short-term infection. It is spread through the fecal-oral route, often through contaminated water Slide 19: Transmission
- Infection is through contaminated material such as earth, water, uncooked or cross-contaminated food that has been in contact with the feces of an infected individual or animal. Contact must then be transferred to the mouth and swallowed.
The disease can be acute diarrhea or persistent diarrhea that can last for a few weeks. Diarrhea is usually watery with mucus.
often stomach pains or cramps and a low fever & vomiting.
- There is no reliable treatment. Certain agents such as paromomycin, atovaquone, nitazoxanide, and azithromycin are sometimes used, but they usually have only temporary effects.
- Treatment is primarily supportive. Fluids need to be replaced orally. A lactose free diet should be taken as tolerated. In rare situations, intravenous fluids may be required. Antibiotics are not usually helpful, and are primarily reserved for persons with severe disease and a weak immune system. Protozoan Parasites of Digestive system : Protozoan Parasites of Digestive system 4. Amoebic Dysentery (Amoebiasis) : 4. Amoebic Dysentery (Amoebiasis) A chronic disease of a large intestine resulting from the ingestion of amoeba. Slide 22: It is the only photogenic amoeba found in the animal intestine. Entamoeba histolytica is the causative agent of amoebic dysentery. Slide 23: Amoebiasis E. Histolytica uses proteins called lectins to attach to the glucose of plasma membrane & causes cell lysis. : E. Histolytica uses proteins called lectins to attach to the glucose of plasma membrane & causes cell lysis. Slide 25: Symptoms
Severe amoebic dysentery results in a feces characteristically contain blood & mucus.
Transmitted by fecal cysts in contaminated food or water. Once ingested, the organism secretes enzymes (special chemicals) that digest in the intestinal lining.
Leads to a perforated colon and peritonitis, which is an inflammation of the lining of the abdominal wall.
Recovering & identifying the pathogens in feces.
Latex agglutination & fluorescent antibody.
Metronidazole plus iodoquinol are the drugs of choice in treatment. Protozoan Disease of Reproductive System : Protozoan Disease of Reproductive System Thricomoniasis An itching of reproductive organ through the inhibition of anaerobic protozoan Tricomonas vaginalis. Slide 27: Trichomonas vaginalis organism feeds on bacteria and white blood cells. It can live outside the body in bath water, on toilet seats, or on washcloths. Slide 28: -Trichomoniasis, is a common STI that usually has very few symptoms.
-It is caused by an infection of microscopic parasites called trichomonas vaginalis.
-For women, these parasites may infect the vagina, urethra, bladder or cervix.
-In men, the infection is usually in the urethra, or under the foreskin of uncircumcised men. Slide 29: Symptoms
- In men, trichomoniasis is rare and most men will not have symptoms.
- For men symptoms may include: Mild discharge, irritation or redness at the top of the penis, burning during urination.
- For women, symptoms may include: Discharge from the vagina, vaginal odor, pain during intercourse or urination, irritation or itchiness of the vagina
Microscopic examination & identification of organism in the discharge.
- Oral metronidazole, administered to both sex partners. Slide 30: TESTING
Testing may be done by physical examination or lab testing to detect the parasite.
In some cases, the tiny sores caused by trichomoniasis may be detected during a routine pap test for women; however, pap smears do not specifically test for sexually transmitted infections, and you should never rely on a pap smear to detect trichomoniasis or any other sexually transmitted infections.
Typically, trichomoniasis can be treated with a single oral dose of an antibiotic called Metronidazole. However, Trichomonas can be reacquired easily so it is important that you and your partner(s) be treated together.
- The best way to help prevent Trichomoniasis is to use a condom each and every time you have sex. Protozoan Disease of Nervous System : Protozoan Disease of Nervous System African
Trypanosomiasis It is named as sleeping disease that is caused by tyrpanosoma brucei gambience & trypanosoma brucei rhodesiense-flagellates that are injected by tsetse fly. Slide 33: Animal reservoirs for two trypanosomes are similar but they occur in different habitats & are spread by many species of tsetse fly. T.b. gambiense circulates in the patients blood to 2-4 yrs course of the disease while the T.b. rhodesiense is about a few months. Slide 35: A drug eflornithine (resurrection drug) is
recommended for treatment of sleeping
disease because it crosses blood-brain
barrier & blocks the enzyme required for
proliferation the parasites. 2. NAEGLERIA MENINGOENCEPHALITIS : 2. NAEGLERIA MENINGOENCEPHALITIS A neorogical disease caused by protozoan naegleria fowleri. Slide 38: The most common victims are children who swim in ponds or streams.
The organism initially proliferates in the brain.
- Diagnosis is typically made at autopsy.
ponds or streams.
- Diagnosis is typically made at autopsy. Protozoan Disease for Cardiovascular System : Protozoan Disease for Cardiovascular System 1. Malaria
- A protozoan cardiovascular disease caused by anopheles mosquito through injection of protozoan parasite plasmodium. Slide 40: Plasmodium life cycle
Anopheles mosquito feeds on blood & serves as the vector.
- Sporozoites enter blood stream and proceed to the liver within 30 min to infect hepatocytes. Slide 41: - 1 week = Multiplication & transformation in the liver leads to the release of about 5,000-10,000 merozites PER HEPATOCYTE infected with only one sporozite!
- Merozites infect red blood cells, initiating the symptoms and pathology of malaria.
- Merozites replicate and differentiate again
- Cell ruptures to release new merozites (which will infect more red blood cells)
- Some merozites differentiate into ♂ and ♀ gametocytes.
- Gametocytes ingested by Female Anopheles differentiate into male and female gametes which fuse to form a zygote and become sporozites in the salivary gland…. Symptoms : Symptoms Chills, fever, sweating—peak every 48hrs.
Weak, anemic, splenomegaly.
- Blocked capillaries = intense headaches, renal failure, heart failure, or cerebral damage. Slide 43: Diagnosis
- The most common diagnostic test is the blood smear.
- Drug quininine, chloroquine, primaquine, & mefloquine. 2. Leishmaniasis : 2. Leishmaniasis Is a widespread & complex disease that exhibits several clinical forms. This disease is transmitted by a bite of female sand fly. Smaller than mosquito and often penetrate mesh of standard netting. Leishmaniasis : Leishmaniasis - Leishmania donovani
- Leishmania tropica
- Leishmania major
- Leishmania aethiopica
- Leishmania peruriana Infective forms : Infective forms Promastigote
Intracellular Slide 47: Amastigotes (*) of Leishmania donovani in the cells of a spleen. The individual amastigotes measure approximately 1 µm in diameter. Slide 48: Leishmania (Leishman-Donovan or LD bodies). Lying in macrophage cells from liver. Giemsa. ×12000. Enlarged by 9.6. Summary of Life cycle : Summary of Life cycle The organism is transmitted by the bite of several species of blood-feeding sand flies (Phlebotomus) which carries the promastigote in the anterior gut and pharynx. It gains access to mononuclear phagocytes where it transform into amastogotes and divides until the infected cell ruptures. The released organisms infect other cells. The sandfly acquires the organisms during the blood meal, the amastigotes transform into flagellate promastigotes and multiply in the gut until the anterior gut and pharynx are packed. Dogs and rodents are common reservoirs. Slide 51: Profile view of a teenage boy suffering from visceral leishmaniasis.
The boy exhibits splenomegaly, distended abdomen and severe muscle wasting. Slide 52: A 12-year-old boy suffering from visceral leishmaniasis. The boy exhibits splenomegaly and severe muscle wasting. Slide 53: Enlarged spleen and liver in an autopsy of an infant dying of visceral leishmaniasis. Cutaneous leishmaniasis of the face. : Cutaneous leishmaniasis of the face. A cutaneous leishmaniasis lesion on the arm. Diagnosis : Diagnosis Clinical signs & symptoms
Bone marrow biopsy
Spleen or liver biopsy
Culture & Histology Treatment Good nursing
New drugs - New deliver y Control
Treatment of active cases
Vaccination 3. Amarican Trypanomiasis (Chagas’ Disease) : 3. Amarican Trypanomiasis (Chagas’ Disease) Is a protozoan disease of cardiovascular system cause by the parasite trypanosoma cruzi, a flagelatted protozoan. Slide 57: Flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly
transmitted to humans and other mammals by an insect vector,
the blood-sucking assassin bugs. The disease may also be
spread through blood transfusion and organ transplantation,
ingestion of food contaminated with parasites, and from a
mother to her fetus.
In Chagas-endemic areas, the main mode of transmission is through an insect vector called a triatomine bug. A triatomine becomes infected with T. cruzi by feeding on the blood of an infected person or animal. Slide 58: Symptoms
The symptoms noted by the patient can include fever, fatigue, body aches, headache, rash, loss of appetite, diarrhea, and vomiting.
Enlargement of the liver or spleen, swollen glands, and local swelling (chagoma) where the parasite entered the body.
Diagnosis The presence of T. cruzi can be detected by Microscopic examination of fresh anti-coagulated blood & by preparation of thin and thick blood smears stained with Giemsa (Giemsa staining). Treatment : Treatment Antiparasitic treatment is most effective early in the course of infection but is not limited to cases in the acute phase. Drugs of choice include azole or nitro
derivatives such as benznidazole or nifurtimox. 4. Toxoplasmosis : 4. Toxoplasmosis A disease of blood & lymphatic vessels that I scause by the protozoan toxoplasma gondii. Slide 61: Toxoplasma gondii
- Flagellated protozoan parasite
- Infects over 200 species of birds and animals
- Primary reservoir is cats
- Infection usually handled by immune system Toxoplasmosis : Toxoplasmosis Acquired from
meat or ingestion
of oocysts in
cat feces. Toxoplasmosis : Toxoplasmosis - Causes serious disease in developing fetus
- Serious disease in people with AIDS.
- Prevention: no raw meat, no contact with cat litter box Transmission : Transmission Diagnosis : Diagnosis Detecting oocysts in the stool
- Antibiotics- Clindamycin- Potentiated Sulfa Drugs Importance : Importance Protozoa play important roles in the fertility of soils. By grazing on soil bacteria, they regulate bacterial populations and maintain them in a state of physiological youth in the active growing phase. This enhances the rates at which bacteria decompose dead organic matter. Protozoa also excrete nitrogen and phosphorus, in the form of ammonium and orthophosphate, as products of their metabolism, and studies have shown that the presence of protozoa in soils enhances plant growth. Slide 67: Protozoa play important roles in wastewater treatment .
Good-quality, clean effluents are produced in the presence of large ciliated protozoan communities because they graze voraciously on dispersed bacteria and because they have the ability to flocculate suspended particulate matter and bacteria. Importance Slide 68: Protozoa probably play a similar role in polluted natural ecosystems. Indeed, there is evidence that, by feeding on oil-degrading bacteria, they decrease bacterial growth in much the same way they enhance rates of decomposition in soils, thereby speeding up the breakdown of oil spillages. Importance Slide 69: Prepared By:
Peter Paul T Sigue
BSED/Biological Science Slide 70: Reference:
Microbiology (an introduction)
2004, Pearson Education, Inc.
1301 Sansome St. San Francisco