MLS3B_Sarcocystis and Toxoplasma

Sarcocystis hominis and Toxoplasma

gondii

Sarcocystis hominis

• Syn: Miescheria cruzi, Sarcocystis fusiformis, and Isospora hominis

• Protozoan parasite, man is the final host.

•The intermediate host is cattle

•Invade the lamina propria of the intestinal mucosa.

•INFECTIVE STAGE: cyst with bradyzoites

Zoite • It is a banana shape cell.• The pointed end is equipped for entering the host cell.

Sporocyst

• Composed of 4 zoites.• Oval and about 9-16 um in length.• Capable of surviving on the

ground.

Sarcocyst

• formed from sporozoites.• composed of a large number of zoites sorrounded by a cyst wall.

•Macrocyst- sarcocyst that can be seen with the naked eye.

• Microcyst- can only be seen under the microscope.

Pathology

•Sarcocystosis– a disease affecting the small bowel and the muscle tissue. Infections occur all over the world.

•Affects people causing muscle or alimentary system sarcocyst

• Sporogenic stages in human are slightly pathogenic.

Clinical signs may include:

• fever• chills,•sweating•diffuse abdominal tenderness

•nausea • vomiting•fever(immunocompromised patient)• known to cause abortion in pregnant animals• mild increase of criatine kinase

In the intermediate host:

• damage of brain muscle and kidney tissue•Loss of appetite•Anemia

•Gait abnormalitiesHeavy infection may result in paralysis or death

Life cycle of Sarcocystis hominis

Diagnosis:

•CT scan or MRI •Concentration methods•Fecal flotation methods(using zinc sulfate flotation.)

•Necroscopy

•ELISA (enzyme-linked immunosurbent assay)

•Serologic test (immunofluorescent antibody test).

•Fixation and Dermal Sensitivity Test

Treatment:

• No effective treatment is known.• Corticostecoids (muscular inflammation)

•Trimethroprim-sulfamethoxazole (intestinal infections)•antiparasitic agents such as metronidazole, and albendazole.

Epidemiology

• Worldwide geographic distribution where several animal food are infected, risk for human infection also increased. .

•Mostly on Southeast Asia• The incidence of intestinal sarcocystosis is estimated to be 6-10%.•This disease is more prevalent in cultures where raw meat is commonly eaten

Prevention and control

• ingestion of sporocysts must be prevented • People can protect themselves by not eating uncooked food.

•Proper disposal of human feces.• Meat should be thoroughly frozen• Good personal hygiene

Toxoplasma gondii

Toxoplasma gondii

•is a unicellular, parasitic protist, classified as an apicomplexan within the group alveolate.

•is a species of parasitic protozoa in the genus Toxoplasma.• Belongs to Phylum Apicomplexa• Five main stages in the life cycle• All five occurs in cat (Felidae)

•amorphous amoeboid-like body form. They have no flagella or other motility structures but move by amoeboid motion.

• 2 stages are found in man, other mammals, and birds.

•The inefective stages include tachyzoite, bradyzoite and oocyst.

• Intermediate hosts: All warm blooded animals including man.

Oocyst

• Typical infective form of T. gondii.• Round to slightly oval form measures 10-15 long and by 8-12 um wide.

Tachyzoites

• Crescent-shaped range in size from 3 to 7 by 2-4 um.• Equipped with centrally located nucleus.• Variety of organelles are present.

Bradyzoites

• Has the physical appearance as the tachyzoite. • Develop a sorrounding membrane and forms a cyst.• Typical cyst measures from 12 to 100 um.

Pathogenesis

• Toxoplasmosis

- assymptomatic if the immune system is functioning well -newborn is seriously affected with the infection

-found in animal feces or undercooked meat.

- Pregnant women and those with a poor immune system should be aware that serious complications may occur.

•Toxoplasmosis infections in people fall into three basic patterns:

1.Congenital toxoplasmosis.2.Cerebral toxoplasmosis (AIDS

patient)3.Toxoplasmosis in

Immunocompromised Patients

Signs and symptoms, if there are any, may include:

•Swollen glands (lymph nodes)•Jaundice •An unusually large or small head

•Rash•Fever•bruises or bleeding under the skin•anemia•enlarged liver or spleen

Some babies with congenital toxoplasmosis have brain and nervous system abnormalities that cause:

•seizures•feeding difficulties•hearing loss•mental retardation

They also at high risk for eye damage.

Life cycle of Toxoplasma gondii

How It Spreads?

• Touching or coming into contact with infected cat feces • Eating raw or undercooked meat that's contaminated

•Eating uncooked, unwashed fruits or vegetables that have been contaminated by manure

•Being born with it

Diagnosis:

• Histological examination of tissue samples. • Antigen or specific antibody using serological methods • Cell culture of the tachyzoite stage from blood or body fluids;

Treatment

• Pyrimethamine ( 25 to 100 mg daily) • Sulfadiazine ( 1 to 1.5 g qid)• Clindamycin• Cortecostecoids• Prophylaxis • Trimethoprim- sulfamethoxazole

Epidemiology:

• Endemic worldwide in humans and domestic animals• Determination of the prevalence of infection is based on serodiagnostic test.• In the Phil. 2.4% is seropositive for T. gondii

Prevention and Control

• Proper cooking of meat• Food should be protected from contamination by cat feces.

•Cat owners are warned to avoid directly handling litter trays or soil that may be contaminated with cat feces• Pregnant women especially should avoid contact with cats