Mary Allen
Feline toxoplasmosis is a parasitic infection that does not usually affect cats but can be uncomfortable for other animals and people. It is distributed worldwide and occurs particularly in temperate, humid climates.
How does the cat get infected with toxoplasmosis? And why is this dangerous for pregnant women? We clarify these questions in the following article.
What is toxoplasmosis in cats?
Toxoplasmas (Toxoplasma gondii) are unicellular parasites for which cats (or other felids, i.e. cat-like) are the definitive host. This means that the parasite becomes sexually mature and multiplies here. Many other mammals (e.g. pigs, sheep, goats), as well as birds and reptiles, serve as intermediate hosts: the parasite goes through certain stages of development in them.
Cat toxoplasmosis is a zoonosis, which means it can also infect humans.
Development of toxoplasma
The development cycle of toxoplasma is relatively complex. They can, but do not have to, affect multiple hosts.
Cat as a definitive host
The cat ingests the toxoplasma from the environment or from infected intermediate hosts, e.g. B. trapped mice. These multiply in the mucous membrane cells in the intestine. Finally, the propagation forms, so-called “oocysts”, are eliminated. They are infectious for several months at around -10°C, and for years at higher temperatures. To do this, however, they still have to go through a small change in the outside world, which lasts about 1-3 days at room temperature, and even 21 days at 11°C.
Cats can also act as intermediate hosts, then the development is as follows:
Cat or another animal as intermediate host:
Intermediate hosts such as humans or other animals (sometimes cats) ingest the oocysts from the environment. This can e.g. B. happen on contaminated water or on the ground (gardening). If you eat raw meat that contains toxoplasma, you can also become infected. Also, the parasite is able to pass from mother to baby through the placenta during pregnancy.
Unlike the final host cat, in which the toxoplasma remains in the intestine, they penetrate the mucous membrane of intermediate hosts and multiply there for the first time. From there, the toxoplasma is distributed to various organs with blood and lymph fluid, e.g. B. liver, lungs, muscles, and nerve tissue, where they continue to multiply and store.
Toxoplasmosis: Symptoms in Cats
Most cats show no or only very mild signs of illness, such as mild diarrhea. The latter applies in particular to young cats, which are infested with toxoplasma in large numbers. A brief fever or swelling of the lymph nodes can also sometimes be observed.
Even if the cat acts as an intermediate host, this is rarely visible. Fever, coughing, diarrhea, eye inflammation, or other symptoms, mainly in young cats, sometimes occur, but these could also have many other causes, i.e. they do not specifically indicate toxoplasmosis in the cat.
Young cats and those with pre-existing conditions are more likely to suffer from toxoplasmosis than healthy adult animals. Cats with a reduced immune response can develop a chronic form with gastrointestinal problems (vomiting, diarrhea, emaciation) or disorders in the nervous system (cramps, impaired gait). Kittens infected with toxoplasmosis in utero often die a few days after birth.
Dogs can also contract toxoplasmosis, and similar principles apply to them: adult, healthy dogs rarely suffer from it. Puppies, on the other hand, can become seriously ill and are generally more susceptible to toxoplasma.
Treatment
Because they are not usually visibly sick, cats are not treated for toxoplasmosis. However, if they do show symptoms, they can be alleviated, e.g. B. with antibiotics and anti-inflammatory substances. However, there is no direct treatment option that reliably kills the toxoplasma in cats.
Can I protect my cat?
Toxoplasmosis does not occur in indoor cats that are fed only cooked food (classic complete food, home-cooked food that has been heated to at least 70°C or frozen for at least three days). On the other hand, outdoor cats that eat rodents and birds cannot be protected from infection.
There is no preventative treatment or vaccine for feline toxoplasmosis that will prevent infection. Hygiene measures such as thorough cleaning (scalding!) of litter boxes and boxes help to break the chain of infection, especially in group housing. Commercially available disinfectants, on the other hand, are not effective.
Toxoplasmosis in humans
Humans become infected with toxoplasmosis v. a. through raw meat, e.g. B. from pigs, cattle, sheep, or goats, less often when gardening or cleaning the litter box.
Feline toxoplasmosis is often asymptomatic in humans and therefore goes undetected. However, it can also occur as an acute or chronic disease associated with lymph node swelling and inflammation in various organs (e.g. eyes, heart, Lung). If the central nervous system (brain, spinal cord) is affected, toxoplasmosis can also be fatal.
As with animals, people with weakened immune systems, pregnant women, and children are particularly at risk of developing severe toxoplasmosis.
Toxoplasmosis in pregnancy
If women contract toxoplasmosis from a cat during pregnancy, it can be very dangerous for the unborn child. Depending on the time of infection and the number of parasites, the embryo is then lost (abortion, 1st trimester), premature birth or stillbirth (2nd and 3rd trimester), or damage that then becomes visible in the infant or toddler. These are often eye infections and brain changes, which can also lead to disorders of fine motor skills or slower learning speed. There are about 3-4 weeks between the infection of the mother and the passing of the placenta to the unborn child.
How can I protect myself from toxoplasmosis?
Pregnant women, children, and people with a weak immune system, in particular, should heed a few tips to reduce the risk of toxoplasmosis infection:
- Do not eat raw or undercooked meat (the most common source of infection). Caution: Some sausage products are made from raw meat!
- Wash hands and clean all surfaces after each contact with raw meat (e.g. when cooking). The same applies to playing in the sandpit or gardening (wear gloves). Always wash your hands and your children thoroughly when you come in from outside.
- Cover the sandbox so cats cannot use it as a toilet.
- Always wash fruit and vegetables thoroughly under running water before eating. Especially if it’s not cooked.
- Thoroughly clean the litter box daily (it takes oocysts 3 days to become infectious), including flushing at the end. It is best not to do this for the pregnant woman herself! If you do: wear disposable gloves and dispose of them hygienically, wash your hands thoroughly afterward, ventilate them well and, if necessary, wear a face mask (dust).
- Particularly susceptible young cats that have not yet gone through toxoplasmosis can be housed elsewhere for the duration of the pregnancy if necessary.
Am I protected against toxoplasmosis if I have had it before?
People who have already had toxoplasmosis form antibodies against the pathogen. These are defense products of the immune system that render the toxoplasma harmless. Women who have had toxoplasmosis BEFORE becoming pregnant are largely safe.
Toxoplasmosis test for cats?
You can also test cats for toxoplasma. The oocysts are found in abundance in the feces during acute infection. Antibodies can be detected with a blood test. Both in combination are the safe clarification of acute toxoplasmosis and should be repeated after 2-3 weeks.
Unfortunately, this is of course only a snapshot: the cat can be Toxoplasma negative today and become infected with it the next day.
But a cat that has already been infected with toxoplasmosis protects: the cat forms antibodies that fight the toxoplasma in the event of new infection in such a way that no infectious oocysts are excreted. Therefore, the antibody test helps to better assess the possible risk for humans.
Toxoplasmosis in the cat: Conclusion
Toxoplasmosis in cats is usually not a problem for the animals themselves. For animals and people with a weakened immune system, however, it can be very unpleasant or even dangerous. Hygiene measures protect against infection, especially in pregnant women. There is no vaccine or treatment for toxoplasmosis in cats, but once infected, the animal is immune.