Toxoplasmosis

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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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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.

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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.

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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.

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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.

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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
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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.

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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

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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

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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.

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Lifecycle of Toxoplasmosis
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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.

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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.

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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.

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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

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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

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Symptoms

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

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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

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Video toxoplasmosis

• http//videos.howstuffworks.com/discovery-health/4
  0842-monsters-inside-me-toxoplasmosis-video.htm -
  video
• http//www.youtube.com/watch?vzHYsZdbS4oEfeature
  related

Dogs lungs with toxo
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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.

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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.

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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.

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

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

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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.

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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.

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Prevention

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

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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.

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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.

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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.

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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.

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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.

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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 160F for 20 minutes.

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For more information

• Contact the Center for Food Security and Public
  Health
• http//www.youtube.com/watch?vzHYsZdbS4oEfeature
  related
• http//videos.howstuffworks.com/discovery-health/4
  0842-monsters-inside-me-toxoplasmosis-video.htm

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Sources

• C612-Toxoplasmosis The Secretariat of the
  Pacific Community March 3, 2011lthttp//wwwx.spc.in
  t/rahs/Manual/Multiple_Species/TOXOPLASMOSISE.HTM
• Toxoplasmosis in small animals Purdue Edu
  newsletters Winter 2003. March 3, 2011
  lthttp//www.addl.purdue.edu/newsletters/2003/winte
  r/Toxoplasmosis.shtml
• Toxoplasmosis Stanford Edu Parasites 2006 March
  4, 2011 lthttp//www.stanford.edu/class/humbio103/p
  arasites2006/toxoplasmosis/diagnosis.html
• Toxoplasmosis World Veternarian Community Site
  March 4, 2011 lthttp//www.vet-zone.com/Pets-Animal
  s/Toxoplasmosis.html

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Sources

• Summers Alleice (2002).Toxoplasmosis In Common
  Diseases of Companion Animals (pp.
  235-236).     St Louis, Missouri Mosby Inc.
• Toxoplasmosis-disease Center for Disease
  Control and prevention November 2, 2010 March
  3, 2011 lthttp//www.cdc.gov/parasites/toxoplasmosi
  s/disease.html
• Toxoplasmosis Medline Plus March 2, 2011
  lthttp//www.nim.nih.gov/medlineplus/ency/article/0
  00637/.htmltreatment
• Effects of Toxoplasma on Human Behavior Oxford
  Journals March 5, 2011 lthttp//schizophreniabulle
  tin.oxfordjournals.org/content/33/3/757.full

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References

• www.cdc.gov/toxoplasmosis
• www.ncbi.nlm.nih.gov
• www.melborne-petminders.com.au/cats_and_toxoplasmo
  sis
• 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