Toxoplasmosis:

Definition, Symptoms, and Potential Complications

 

Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. It can be contracted through contact with a cat carrying the parasite or by consuming contaminated food (such as undercooked meat or unwashed fruits and vegetables). This disease is often asymptomatic but can be particularly dangerous for fetuses if the infection occurs in a pregnant woman, as well as for individuals with weakened immune systems.

Characteristics of Toxoplasmosis Toxo ia2 engl

  • Type of Disease: Infectious, caused by a parasite.
  • Transmission:
    • Not contagious between humans.
    • 80% of infected individuals, including pregnant women, show no symptoms.
    • Toxoplasmosis can cause serious complications in:
      • Immunocompromised individuals,
      • Fetuses when the mother contracts the disease during pregnancy.
  • Immunity: Once infected, individuals develop lifelong immunity.
  • Prevalence in France: With improved living conditions, the percentage of immune individuals has decreased to 30%, particularly among pregnant women.

Modes of Contamination

Contamination by Toxoplasma gondii can occur through the following ways:

  • Animal Hosts:

    • Herbivores and omnivores (such as pigs, cattle, and sheep) can host the parasite in an inactive form (cysts), generally without exhibiting symptoms.
    • Consumption of undercooked meat, especially pork and beef, can lead to infection if viable cysts are present.

  • Cats and Felines:

    • Cats, as definitive hosts, can transmit the parasite in its active form (oocysts) through their feces, contaminating the environment.
    • Note: Only cats that hunt and eat prey are likely carriers. A house cat fed with industrial food presents little risk of contamination.

  • Common Sources of Contamination:

    • Direct contact with an infected cat or its litter,
    • Soil or river water contaminated by feline feces,
    • Unwashed raw fruits and vegetables.

  • At-risk Professions:

    • Veterinarians, farmers, gardeners, abattoir workers, butchers, and cooks are more exposed to the risk of contamination.

  • Fetal Transmission:

    • When a pregnant woman contracts toxoplasmosis, the parasite can cross the placental barrier and infect the fetus.

Symptoms of Toxoplasmosis

Toxoplasmosis is often silent, but when symptoms do appear, they may include:

  • Incubation: Estimated to last between 5 and 10 days post-infection.
  • General Symptoms:
    • Moderate fever (below 38°C/100.4°F),
    • Swollen lymph nodes, primarily in the neck,
    • Mild rash,
    • Prolonged fatigue,
    • Headaches,
    • Joint and muscle pain.
  • Specific Symptoms:
    • In cases from Latin America or Africa, chorioretinitis (ocular inflammation) has been observed.

Toxoplasmosis in Immunocompromised Individuals

People with weakened immune systems (such as those with HIV, post-transplant, or undergoing immunosuppressive treatments) may experience a reactivation of toxoplasmosis, leading to severe symptoms:

  • Brain involvement (abscess):
    • High fever (above 38°C/100.4°F),
    • Severe headaches,
    • Seizures,
    • Paralysis in certain body parts.
  • Eye Complications:
    • Decreased visual acuity,
    • Redness in the eye.

Congenital Toxoplasmosis

  • Transmission:

    • If a non-immune pregnant woman contracts toxoplasmosis, the parasite may reach the fetus.

  • Possible Complications:

    • Toxoplasmosis can lead to serious neurological sequelae (brain development abnormalities, psychomotor delay) and, in severe cases, intrauterine death or premature birth.
    • Chorioretinitis: Eye inflammation that may manifest after birth, during adolescence, or in adulthood, potentially leading to vision impairment.

  • Surveillance in France (2022):

    • Of the 131 recorded cases:
      • 106 babies were born without abnormal symptoms.
      • 9 babies presented signs of moderate or severe congenital toxoplasmosis.

  • Fetal Transmission Risks:

    • The risk of transmission increases as the pregnancy progresses:
      • First trimester: 10%,
      • Second trimester: 30%,
      • Third trimester: 60%.
    • However, lesions are generally less severe if the infection occurs later in the pregnancy.

Source: Ameli.fr