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Toxoplasmosis Is a protozoan shed in cats that can be spread to humans by a variety of ways. Presented by: Navies 2011e.

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Presentation on theme: "Toxoplasmosis Is a protozoan shed in cats that can be spread to humans by a variety of ways. Presented by: Navies 2011e."— Presentation transcript:

1 Toxoplasmosis Is a protozoan shed in cats that can be spread to humans by a variety of ways. Presented by: Navies 2011e

2 History of Disease Toxoplasmosis gondi was first observed in rodents by Nicolle and Manceuax in 1908. Identified as an agent of infectious disease in 1932. First case that was document occurred in a congenitally infected infant. In 1968 it became recognized as a severe and fatal disease of adults after more cases were found in patients with hematological cancers. It then became more widely recorded as a cause of morbidity in immune deficient patients, including AIDS patients beginning in 1983. It continues to be an important disease in the modern world, especially in pregnant women and immune compromised patients.

3 What causes Toxo? A single-celled coccidian parasite called Toxoplasma gondii causes a disease known as toxoplasmosis. Eating undercooked, contaminated meat (pork, lamb, and venison). Eating food contaminated by knives, utensils, cutting boards and other foods that have had contact with raw, contaminated meats. Drinking water contaminated with Toxoplasma Gondii. Swallowing the parasite through contact with cat feces that contain Toxoplasma. This might happen by cleaning a cats litter box when the cat has shed Toxoplasma in its feces. Touching or ingesting anything that has come into contact with cat feces that is contaminated. Ingesting contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits and vegetables from a garden.

4 What is Toxo? Mother-to-child (congenital) transmission. Receiving an infected organ transplant or infected blood via transfusion, though this is rare. Toxoplasma gondii, being a protozoan, is a small organism that lives inside the cells of the host animal or person. Since its discovery it has been found in virtually all warm-blooded animals including most pets, livestock and human beings.

5 Cause of Toxoplasmosis
Toxoplasmosis is an infection caused by a single celled microscopic parasite called Toxoplasma gondi. More than 60 million people in the United States carry the Toxoplasma parasite. Toxoplasmosis can cause severe illness in infants infected before birth (mothers newly infected during pregnancy) or in in persons with a weakened immune system. Cats spread toxoplasmosis when they eat small animals or anything contaminated with feces from another cat that is releasing the parasite.

6 Cause of Toxoplasmosis
After a cat has been infected, it releases the feces. The parasite can live in the environment for many months and contaminate, soil, water, fruits, vegetables, sandboxes, grass where animals graze for food, litter boxes, or any place where an infected cat may have defecated. People become infected with toxoplasmosis through several ways: Eating food, drinking water or accidentally swallowing soil that has been contaminated with infected cat feces Raw meat infected with toxoplasmosis

7 Causes of Toxoplasmosis
Eating raw or undercooked meat from animals (especially pork, lamb, venison ) that have been infected with toxoplasmosis Eating food contaminated by knives, utensils, cutting boards and other foods that have had contact with raw, contaminated meats. Drinking water contaminated with Toxoplasma Gondii. Directly from pregnant woman to unborn child when the mother becomes infected with toxoplasmosis during pregnancy. Touching or ingesting anything that has come into contact with cat feces that is contaminated. Ingesting contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits and vegetables from a garden.


9 Signalment Can be found in cats of all ages and sex
More common in adult cats In cats there are two tissues that are involved, the lungs and the eyes, whereas in dogs the gastrointestinal, neurologic and the respiratory system are infected. Toxoplasmosis infections are rare in dogs. Intermediate host is all other warm blooded animals Dangerous for pregnant women and unborn fetus as well as people with compromised immune systems

10 Transmission Eating infected meat: Primary source of transmission to humas Ingestion of recently infected feces Transmission of mother to fetus (it is zoonotic) 2 infection stages Latent: bradyzoites in nervous tissue Acute: flu like symptoms swollen lymph nodes (neck, axillae, groin) Pain lasting month or longer

11 Who is at risk? Most species of animals and birds can contract Toxo. Although cats are the definitive host of the parasite. People who are most likely to develop severe toxoplasmosis include infants born to mothers who are newly infected with Toxoplasma gondii during or just before pregnancy. Persons with severely weakened immune systems, such as individuals with HIV/AIDS. Those taking certain types of chemotherapy. Those who have recently received an organ transplant.

12 Lifecycle of Toxoplasmosis

13 Life Cycle - 1 Life cycle: When a cat ingests an infected prey (or other infected raw meat) the parasite is released into the cat's digestive tract. The organisms then multiply in the wall of the small intestine and produce oocysts during what is known as the intraintestinal infection cycle. These oocysts are then excreted in great numbers in the cat's feces. Cats previously unexposed to T. gondii will usually begin shedding oocysts between three and 10 days after ingestion of infected tissue, and continue shedding for around 10 to 14 days, during which time many millions of oocysts may be produced. Oocysts are very resistant and may survive in the environment for well over a year.

14 Life cycle - 2 During the intraintestinal infection cycle in the cat, some T. gondii organisms released from the ingested cysts penetrate more deeply into the wall of the intestine and multiply as tachyzoite forms. These forms then spread out from the intestine to other parts of the cat's body, starting the extraintestinal infection cycle. Eventually, the cat's immune system restrains this stage of the organism, which then enters a dormant or "resting" stage by forming cysts in muscles and brain. These cysts contain bradyzoites, or slowly multiplying organisms.

15 Lifecycle - 3 Other animals, including humans, are intermediate hosts of Toxoplasma gondii. These hosts can become infected but do not produce oocysts. Oocysts passed in a cat's feces are not immediately infectious to other animals. They must first go through a process called sporulation, which takes one to five days depending on environmental conditions. Once sporulated, oocysts are infectious to cats, people, and other intermediate hosts. Intermediate hosts become infected through ingestion of sporulated oocysts, and this infection results in formation of tissue cysts in various tissues of the body. Tissue cysts remain in the intermediate host for life and are infectious to cats, people and other intermediate hosts if the cyst-containing tissue is eaten.

16 Clinical signs Most primary infections produce no symptoms.
Time between exposure to the parasite and symptom development is 1-2 weeks. Mostly in severely immunocompromised or very young animal. Cats: Lung and eye; In muscles : protozoal myositis Dogs: GI, neurologic and respiratory

17 Symptoms Most infections produce no symptoms. The time between exposure to the parasite and system development is 1-2 weeks. The disease can affect the brain, lung, heart, eyes or liver. Symptoms in persons with otherwise healthy immune systems. Abortion (especially in 1st and 2nd trimester) Fetus can have hydrocephalus Enlarged lymph nodes in the head and neck Headache Mild illness with fever, similar to mononucleosis Muscle pain Sore throat

18 Symptoms Symptoms in immune suppressed persons: Confusion Fever
Headache Retinal inflammation that causes blurred vision Seizures

19 Diagnostic tests and expected results
Antibody titer for toxoplasmosis Fecal examination for toxoplasma oocysts Cranial CT scan MRI of head Slit lamp exam Brain biopsy ELISA Fulton test Indirect Fluorescent Antibody test

20 Video toxoplasmosis - video Dogs lungs with toxo

21 Recommended treatment
No treatment is required for a healthy person, symptoms go away within several weeks to months. Sulfadiazine and Pyrimethamine are used in the acute state of toxoplasmosis. In difficult cases spiramycin is used Clindamycin is the treatment of choice for dogs/cats. Antibiotics do not destroy the infection. It is an infection you live with the rest of your life.

22 Prognosis Acute infection in children may cause swelling of the retina of the eye. In cats most have a poor prognosis with a severe infection due to the intense dehydration. Adults that are healthy have a good outcome. Complications may occur with this disease: Personal disabilities such as blindness, learning disorders in infants with congenital toxoplasmosis. Return of the disease Spread of the infection in a person with a weakened immune system.

23 Pathologic lesions of disease
In tissues rapidly multiplying tachyzoites (trophozoites) and cysts may be identified. The presence of tachyzoites is diagnostic of acute infection. Cysts containing hundreds and sometimes thousands of bradyzoites make their appearance in brain, skeletal muscles, and other tissues with the development of immunity. Rupture of these cysts has been proposed as a pathogenetic mechanisms for the development of inflammatory lesions. Lesions can occur in any tissue of the body.

24 Pathologic lesions of disease
16 week intrauterine fetal demise due to Toxoplasmosis. Organism is preserved despite autolysis of fetus Toxoplasmosis in heart



27 The first 3 pictures are lesions in the brain and CNS.
Pathologic Lesions The first 3 pictures are lesions in the brain and CNS. The last picture are lesions in a newborn with Toxo

28 Prevention Wash your hands with soap and water after exposure to soil, sand, raw meat or unwashed vegetables. Cook your meat thoroughly Wash and/or peel all fruits and vegetables before eating them. Wear gloves when gardening or handling sand from a sandbox. Wash hands well afterwards.

29 Prevention Avoid drinking untreated water especially in less developed countries. If you are pregnant: Have someone else change your litter box if possible. If not then wear disposable gloves and wash your hands thoroughly. Change the litter box daily because the parasite does not become infectious until 1-5 days after it is shed in the feces. Never feed a cat raw meat. Keep indoor cats indoors. Avoid stray cats, especially kittens.

30 Prevention Cover your outdoor sandboxes.
Do not get a new cat while you are pregnant.

31 Case Study-Effects of Toxoplasmosis on Human Behavior
A series of tests have been conducted in the Czech Republic comparing those who have anamnestic antibodies to T. gondii and are assumed to have a latent infection and those without the antibodies. The subjects varied: some were military conscripts, blood donors, women tested for toxoplasmosis during pregnancy and individuals known to have had symptomatic toxoplasmosis in the past. Infected humans were compared to uninfected humans on personality questionnaires or on a panel of behavioral tests. Consistent and significant differences were found between the 2 groups in 9 of 11 studies, and the differences were not the same for men and women. Infected men had lower superego strength and were found to more likely to disregard rules and were more expedient, suspicious, jealous and dogmatic. Infected women had higher superego strength factors and were more warm hearted, outgoing, conscientious, persistent and moralistic.

32 Case Study-Effects of Toxoplasmosis on Human Behavior
Testing was also done on psychomotor performance between the infected and non infected group. Those infected lost concentration more quickly and performed more poorly. A higher incidence of traffic accidents was found in infected subjects when compared to non infected subjects in one of the studies. Results obtained from current testing strongly suggests that toxoplasmosis influences the behavior of humans. Further testing is required to determine the neurophysiological mechanisms and effects of these behavioral changes.

33 Client education What is Toxoplasmosis? Disease caused by a microscopic protozoal parasite called Toxoplasma gondii. The organism has a complex life cycle and is found worldwide. What animals get toxo? Many animal species can get toxoplasmosis. Cats are required for the lifecycle of the organism. Infection is common in cats, sheep, goats and swine. Cattle seem to be immune. Dogs can so be infected. How can my animal get Toxoplasmosis? Toxoplasmosis eggs are shed in the feces of infected cats.

34 Client education These eggs are then ingested by other animals either by grazing or eating other small mammals. The protozoa can also be transmitted during pregnancy thereby infecting the unborn fetus. Does Toxoplasmosis affect my animal? Most animals show no signs of illness. Most often it is seen in young animals. In adult animals, especially sheep the most noticeable sign is abortion. Cats may show signs of pneumonia or damage to the nervous system or eyes. Dogs may show signs of encephalitis, such as seizures, head tilt, tremors, or paralysis.

35 Client education Can I get toxoplasmosis? Humans can get toxoplasmosis by ingesting orally the toxoplasmosis gondii eggs or cysts from fecally contaminated raw vegetable or undercooked food. It can also be spread by contact with feces from an infected cat. What are they symptoms? Symptoms begin with flu like signs. Severe disease can occur if the the protozoan invades the muscles, nervous system, heart, lungs or eyes. It can cause abortion or birth defects in pregnant women. It can also cause brain infection in persons with AIDS.

36 Client education How can I protect my animal from toxoplasmosis? Keep cats indoors to prevent them from becoming infected or shedding the oocytes in the environment. Keep them out of livestock areas. Feed animals commercially prepared foods. Do not feed raw or undercooked meats. How can I protect myself? Proper food preparation. Meats should be thoroughly cooked. Wash fruits and vegetables before eating them. Wear gloves when gardening or when changing cat litter box. Wash your hands after any contact with an animal. Meat should be cooked to a temperature of at least 160°F for 20 minutes.

37 For more information Contact the Center for Food Security and Public Health

38 Sources “C612-Toxoplasmosis” The Secretariat of the Pacific Community March 3, 2011< “Toxoplasmosis in small animals” Purdue Edu newsletters Winter March 3, 2011 < “Toxoplasmosis” Stanford Edu Parasites 2006 March 4, 2011 < “Toxoplasmosis” World Veternarian Community Site March 4, 2011 <

39 Sources Summers Alleice (2002).Toxoplasmosis In Common Diseases of Companion Animals (pp ).     St Louis, Missouri: Mosby Inc. “Toxoplasmosis-disease” Center for Disease Control and prevention” November 2, 2010 March 3, 2011 < “Toxoplasmosis” Medline Plus March 2, 2011 < “Effects of Toxoplasma on Human Behavior” Oxford Journals March 5, 2011 <

40 References
Liesenfeld O. Toxoplasmosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 370 Review date: 12/1/2009 Reviewed by: David C Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, Medical Director, A.D.A.M, Inc

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