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Very high magnification micrograph of toxoplasmosis. Brain biopsy. HPS stain.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Disseminated Toxoplasmosis
  • Toxoplasma Gondii Infection
  • Toxoplasmosis, NOS

What is Toxoplasmosis? (Definition/Background Information)

  • Infection by Toxoplasma gondii, which is a common microorganism (classified as protozoa), causes Toxoplasmosis. This condition is generally caused by consuming meat that is contaminated by the parasitic microorganism. The contamination can occur even during the cooking or preparation stage
  • Cats are host to the microorganism; cat feces are a possible source of the protozoa. An accidental ingestion of the same, can also cause Toxoplasmosis
  • This infection normally does not affect an individual with healthy immune system. However, pregnant women and those suffering from various immunodeficiencies may be severely affected. In such individuals, complications can arise, which can lead to life-threatening situations
  • Treatment measures of Toxoplasmosis include prescription oral medications, controlling related symptoms (such as fever, body pain), and taking plenty of rest
  • The prognosis of Toxoplasmosis is dependent upon the health status of an individual; in those with poor immune system, the prognosis is guarded
  • Adequate preventive steps for Toxoplasmosis may include consuming well-cooked meat and drinking clean water. This may reduce incidence of the condition and stop its transmission

Who gets Toxoplasmosis? (Age and Sex Distribution)

  • Any individual, young or old, may contract Toxoplasmosis; there is no age or gender preference. Individuals with weak immune systems are prone to developing severe symptoms
  • A baby in the womb or a newborn child can be infected by the mother, who is recently infected. This transplacental vertical infection from mother to the developing fetus can cause damaging affects in the unborn child
  • Toxoplasmosis is very common in parts of Europe, South America, Asia, and Africa - regions with hot-humid climate. A majority of the human population carry this parasite in a latent state, within their body

What are the Risk Factors for Toxoplasmosis? (Predisposing Factors)

The risk factors of Toxoplasmosis include:

  • Consuming meat (beef, lamb, pork, and venison) that is partially-cooked, or cooked improperly (without maintaining proper hygienic standards, like using contaminated vessels, knives)
  • Inadvertently touching one’s face, mouth, while handling contaminated raw meat; not following safe meat preparation procedures
  • Eating raw vegetables and fruits, without washing or cleaning them
  • Drinking untreated water from a stream or a well, or from any such source that is contaminated
  • Direct exposure to cat feces, or to soil contaminated by the feces
  • Living in crowded neighborhoods and/or travelling to areas with poor sanitation facilities
  • Eating food that is mass-prepared (using contaminated meat) without proper quality control
  • Infected blood transfusion or organ transplant recipients
  • Individuals with weak immunity constitution (caused by factors like AIDS/HIV, cancer, organ transplant, diabetes, and so on) are easily infected
  • A newborn baby is at risk to develop severe Toxoplasmosis, if the mother is ‘recently’ infected by the microorganism
  • Individuals working at high-risk zones, such as meat processing/packing plants, pet stores, zoos, and veterinary hospitals, are prone to Toxoplasmosis Infection to a higher degree

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Toxoplasmosis? (Etiology)

Toxoplasmosis infection may be caused by:

  • Consuming undercooked or improperly cooked meat, including handling raw meat, using kitchen items contaminated by raw meat, or taking unclean water, is the primary cause of Toxoplasmosis. The protozoa Toxoplasma gondii (an unicellular organism) is responsible for the infection
  • Cats (even pets) act as a primary host to the microorganism. Individuals handling cat feces (including feces-infected soil), cleaning their resting area/shelter box, etc. have to be extremely careful, since an accidental ingestion of the contaminant will cause an infection
  • Infected garden soils (with cat feces), where plants/vegetables/fruits are home-grown, may also serve as transmission agents. Eating raw fruits and vegetables, without cleaning or washing them, can also cause Toxoplasmosis
  • Congenital transmission of the infection can take place from a mother to the infant child, in the womb (known as vertical transplacental transmission of infection)
  • There are also some rare instances, when the parasitic infection is passed on, via a blood transfusion or from an infected organ donor, during an organ transplant
  • Often, when food prepared for a large community is contaminated, like at restaurants, school dormitories, or when prepared for social or festival occasions; Toxoplasmosis may simultaneously affect many individuals, causing a local endemic infection

What are the Signs and Symptoms of Toxoplasmosis?

The onset of signs and symptoms of Toxoplasmosis, which occur within 10-14 days after being infected with the parasitic organism, depend on the health condition of the individual affected and the severity of the infection. These are categorized as:

  • Normal, healthy individuals (including most newborn babies) usually do not exhibit any signs of the infection, but act as a carrier of the protozoa. This condition is referred to as Latent Toxoplasmosis. If any signs and symptoms are exhibited, they are mild and these may include:
    • Fever
    • Headaches, body aches
    • Enlarged lymph nodes
    • Sore throat (sometimes)
  • In case of Acute Toxoplasmosis, some individuals may have flu-like symptoms, with muscle aches and body aches, swollen lymph nodes, which subside after 1-2 months
  • Infrequently, itchy eruptions on the skin with formation of nodules or lesions are observed. This condition is referred to as Cutaneous Toxoplasmosis

Individuals with weak immune systems may be severely affected and suffer damage to the eyes, brain, lungs, and other vital organs. In such cases, either the parasite (which the individual carried) gets reactivated due to favorable conditions, or a recent infection might have occurred. The signs and symptoms in such cases may include:

  • Reduced vision or blurred vision, vision impairment, sensitivity to light, eye pain, redness of the eyes
  • Anxiety, confusion, lack of coherent (focused) behavior, even seizures
  • Fever and headaches

How is Toxoplasmosis Diagnosed?

Diagnosing a case of Toxoplasmosis is not easy, since many parts of the body, including the central nervous system could be involved. The physician performs a physical examination to study the signs and symptoms and evaluates the medical history of the patient.

Some of the exams and tests that could be ordered include:

  • Blood samples are examined, to detect the presence of the microorganism causing the infection. Some of these tests include:
    • Polymerase chain reaction test (PCR test for Toxoplasmosis)
    • ELISA test for Toxoplasmosis
    • Sabin-Feldman dye test for Toxoplasmosis
  • Biopsy of the brain: The biopsy is examined under a microscope by the pathologist, to arrive at a definitive diagnosis. A biopsy is performed, if Toxoplasmosis causes a brain infection
  • CT scan of head
  • MRI scan of the brain
  • Eye examination using a slit-lamp

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Toxoplasmosis?

A few complications due to Toxoplasmosis are:

  • The Toxoplasma is retained in the body even after recovery. This may get reactivated, when conditions are favorable and the infection could recur
  • Individuals with weak immune systems can be ‘severely-to-fatally’ affected, with the infection spreading all over the body
  • Toxoplasmosis could affect the brain and cause certain behavioral changes
  • Side effects of treatment medication
  • In pregnant women, the fetus could be infected via the placenta and it may develop growth abnormalities and mental disorders. Owing to this, miscarriage, stillbirth, or death of the infant following its birth, are other severe complications of Toxoplasmosis

How is Toxoplasmosis Treated?

Most cases of Toxoplasmosis are self-limiting, meaning that a healthy individual usually recovers from the condition in a few weeks.

  • In such cases, no treatment for Toxoplasmosis is usually required, or the infection may be treated symptomatically by the physician, as required
  • Pregnant women and infants require medication and sometimes extensive treatment
  • Prolonged treatment of Toxoplasmosis, with antibiotics and even antimalarial drugs, may be required for immunocompromised individuals, who are infected by the Toxoplasmosis parasite

How can Toxoplasmosis be Prevented?

To reduce the incidence of Toxoplasmosis, proper precautions have to be taken to prevent transmission of the harmful protozoa via food and water. This has to be considered, even while traveling, to other countries and cities. Pregnant women have a high-risk of the infection being transmitted to their babies; hence, they must be particularly careful.

Some preventative measures for Toxoplasmosis include:

  • Avoid undercooked food (mainly meat) and contaminated water; always drink water that is clean and from a reliable source
  • Follow basic rules while cooking and consuming food, such as:
    • Carefully washing food items (like meat and vegetables)
    • Washing food vessels, cutting boards, etc. before use
    • Cooking meat to the required temperatures, to kill any microorganism
    • Keeping food items covered, stored properly
    • Washing hands before eating, or immediately after handling raw meat
  • Sample tasting of meat, while it is being cooked (or while still undercooked), is to be avoided
  • Fruits and vegetables have to be washed and cleaned well, particularly if they are to be consumed raw
  • Be extremely careful while handling cat feces, or while cleaning cat litter boxes (use hand gloves). Also, ensure that the litter boxes are cleaned regularly
  • Train children to understand the importance of washing their hands, especially after playing in the mud, after playing outdoors
  • Garden soil may be contaminated with Toxoplasma found in cat feces - ensure that you wash your hands thoroughly with soap and water after being in contact with the soil (due to activities, such as gardening or backyard cleaning)
  • If you belong to any of the high-risk groups, such as working at a vet clinic, a pet store, or having a weak immune system; then, do ensure that you take adequate safety precautions while handling cats (or other pets), also avoid touching or playing with stray cats

All these factors contribute in preventing a Toxoplasmosis infection.

What is the Prognosis of Toxoplasmosis? (Outcomes/Resolutions)

  • A healthy individual usually recovers from Toxoplasmosis within a few days, even if no treatment is given and only certain basic self-care steps are followed (like drinking enough fluids, getting adequate rest, etc.). The prognosis of Toxoplasmosis in such cases is excellent
  • Prompt treatment of the infection is necessary, if the patients are newborn babies, very young infants, or pregnant women. If treatment is delayed in such cases, the prognosis of Toxoplasmosis is guarded
  • High mortality rates are generally associated with untreated cases, in individuals with weak immune systems. A prolonged treatment is required to prevent the disease from recurring in them. The prognosis for Toxoplasmosis in individuals with a weak immune system is poor, if no treatment is given

Additional and Relevant Useful Information for Toxoplasmosis:

  • The prevention and treatment of Toxoplasmosis can be accomplished to a good extent through mass-education. This should include providing information on proper hygiene, maintaining good food preparation practices, and following the outlined preventive measures (mentioned above)
  • The microorganism Toxoplasma gondii is also said to be associated with an individual’s psychological wellness. Toxoplasmosis can cause behavioral problems, like schizophrenia, depression, uneasiness, etc.
  • It is best not to get pregnant, if you have had a recent infection of Toxoplasmosis. It is advisable to consult your gynecologist to plan your child, in such cases

What are some Useful Resources for Additional Information?

Centers for Disease Control and Prevention (CDC)
1600 Clifton Rd. Atlanta, GA 30333, USA
Phone: (404) 639-3534
Toll-Free: 800-CDC-INFO (800-232-4636)
TTY: (888) 232-6348
Email: cdcinfo@cdc.gov
Website: http://www.cdc.gov

References and Information Sources used for the Article:

http://www.cdc.gov/parasites/toxoplasmosis/gen_info/faqs.html (accessed on 5/28/14)

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001661/ (accessed on 5/28/14)

http://www.babycenter.com/0_toxoplasmosis-during-pregnancy_1461.bc?showAll=true (accessed on 5/28/14)

http://www.humanesociety.org/animals/resources/tips/toxoplasmosis.html (accessed on 5/28/14)

http://www.cat-world.com.au/pregnancy-a-toxoplasmosis (accessed on 5/28/14)

http://www.americanpregnancy.org/pregnancycomplications/toxoplasmosis.html (accessed on 5/28/14)

Helpful Peer-Reviewed Medical Articles:

Di Mario, S., Basevi, V., Gagliotti, C., Spettoli, D., Gori, G., D'Amico, R., & Magrini, N. (2013). Prenatal education for congenital toxoplasmosis. Cochrane Database Syst Rev, 2, CD006171. doi: 10.1002/14651858.CD006171.pub3

Dupont, C. D., Christian, D. A., & Hunter, C. A. (2012). Immune response and immunopathology during toxoplasmosis. Semin Immunopathol, 34(6), 793-813. doi: 10.1007/s00281-012-0339-3

Mandelbrot, L. (2012). [Prevention of mother-to-child transmission of toxoplasmosis: perspectives]. Gynecol Obstet Fertil, 40(10), 591-598. doi: 10.1016/j.gyobfe.2012.07.033

Sauer, A., Villard, O., Bourcier, T., Speeg-Schatz, C., & Candolfi, E. (2013). [Ocular toxoplasmosis: from pathophysiology to microbiological diagnosis]. J Fr Ophtalmol, 36(1), 76-81. doi: 10.1016/j.jfo.2012.05.004

Vasconcelos-Santos, D. V. (2012). Ocular manifestations of systemic disease: toxoplasmosis. Curr Opin Ophthalmol, 23(6), 543-550. doi: 10.1097/ICU.0b013e328358bae5

Bowie, W. R., King, A. S., Werker, D. H., Isaac-Renton, J. L., Bell, A., Eng, S. B., & Marion, S. A. (1997). Outbreak of toxoplasmosis associated with municipal drinking water. The Lancet, 350(9072), 173-177.

McCabe, R., & Remington, J. S. (1988). Toxoplasmosis: the time has come.

Koppe, J. G., Loewer-Sieger, D. H., & de Roever-Bonnet, H. (1986). Results of 20-year follow-up of congenital toxoplasmosis. The Lancet, 327(8475), 254-256.

Dubey, J. P. (2004). Toxoplasmosis–a waterborne zoonosis. Veterinary parasitology, 126(1-2), 57-72.

Porter, S. B., & Sande, M. A. (1992). Toxoplasmosis of the central nervous system in the acquired immunodeficiency syndrome. New England Journal of Medicine, 327(23), 1643-1648.

Benenson, M. W., Takafuji, E. T., Lemon, S. M., Greenup, R. L., & Sulzer, A. J. (1982). Oocyst-transmitted toxoplasmosis associated with ingestion of contaminated water. New England Journal of Medicine, 307(11), 666-669.