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What is Toxoplasmosis?


Toxoplasmosis is a disease caused by a microscopic parasite called Toxaplasma gondii. It is not a new disease, having first been discovered in 1908. Many warm-blooded animals, including most pets, livestock, birds, and people can become infected with T. gondii.{{more}}

Although infection with the parasite is relatively common, actual disease is rare. Signs of illness include mild flu-like symptoms such as fever, mild aches and pains, and enlarged lymph nodes for a short period of time.

How do people become infected with T. gondii?

There are 3 principal ways Toxaplasma gondii infection is acquired.

l Ingestion of infectious oocysts from the environment – soil or water contaminated with cat feces.

l Consumption of uncooked or raw meat, or unpasteurized milk from animals that have been infected with the organism.

l Transmission directly to an unborn child from the mother when she becomes infected with T. gondii during pregnancy.

The consumption of uncooked or raw meat is the most common route of infection.

T. gondii cysts may be found in meats of sheep, pigs and goats. They are less frequently found in poultry, and cattle.

While nearly all warm – blooded animals can have tissue cysts in their meat or milk, cats are the only definitive host of T. gondii. This means that they are the only animals that pass the infectious in their feces. These oocysts must spend at least 24 hours in the environment to develop into an infectious stage before they can infect other animals, including people. Oocysts are very hardy and can persist for months or years in the environment. They can be carried long distances in wind and water.

What are the dangers of toxoplasmosis in people?

There are two populations at high risk for toxoplasmosis – pregnant mothers and immuno-compromised individuals (Peg. People with AIDS).

Women exposed to T. gondii during pregnancy can pass the infection to the fetus (resulting in congenital infection). Although the majority of infected infants show no symptoms at birth, many are likely to develop signs of infection later in life. Children congenitally infected may suffer from loss of vision, mental developmental disability, loss of hearing, and, in severe cases, death.

Women infected prior to pregnancy will have antibodies to the parasite, and are not at risk of passing the infection to their unborn child.

Usually, people that develop toxaplasmosis after infection with HIV were exposed to the T. gondii parasite earlier in life, and the immuno-supression caused by the HIV infection simply allowed the parasite to grow unchecked. Toxoplasmosis in these patients can result in severe neurologic disease, convulsions, paralysis, coma, and death despite appropriate treatment.

How can human exposure to toxoplasmosis be prevented?

1. Change cat litter daily before T. gondii oocysts “ripen” and become infectious. Dispose of used litter safely, preferably is a sealed plastic bag. If pregnant or immuno-compromised, avoid changing the litter box or use rubber gloves when doing so and wash hands thoroughly afterwards.

2. Wash vegetables thoroughly before eating, especially those grown in backyard gardens.

3. Wash hands with soap and water after working with soil or handling raw or uncooked meat, vegetables, or unpasteurized dairy products.

4. When cooking, avoid tasting meat before it is fully cooked.

5. Make sure meats are cooked to destroy the oocysts.

How do cats become infected with T. gondii?

The most common way cats become infected is from eating infected mice, birds, and other small animals.

For indoor cats, the most likely source is uncooked meat scraps. When a cat eats meat or other tissues from infected animals, it becomes infected with T. gondii and can excrete millions of oocysts in its feces each day. The release of oocysts can continue for more than 2 weeks. After the initial infection and shedding period, most cats will not pass oocysts in their feces again, even if re-infected.

Oocysts in feces become infectious one to five days after being passed in cat feces. Since most healthy cats groom themselves frequently, it is unlikely that feces would remain on their fur long enough for oocysts to become infectious. Therefore, handling cats is unlikely to pose a risk of T.gondii infections for humans.

Can T. gondii make my cat sick?

Most infected cats appear healthy, with no visible signs of illness. However, some cats may develop pneumonia, liver damage, and other health problems. Signs of illness include lethargy, loss of appetite, coughing, difficult breathing, diarrhea, jaundice, blindness, personality changes, and other neurological problems. There is currently no vaccine available for T.gondii, but treatment can be effective if the disease is diagnosed early.

For further information, contact: Dr. Collin Boyle

Unique Animal Care Co. Ltd. Tel: 456 4981