mKitty, Kitty… Go back, Kitty! The possibility of get toxoplasmosis from cats terrifies many pregnant women. But this infection, which can actually be risky for the fetus, is actually transmitted in a rather complicated way by domestic felines. Much more frequent is that a woman contracts it by eating raw meat or vegetables. To shed light on toxoplasmosis, the veterinary analysis laboratory MYLAV it involved two of its experts – Dr. Luigi Venco (Board-Certified at the European College of Veterinary Parasitology) and Dr. Francesca Tamarozzi (Graduated in human and veterinary medicine, expert in parasitology). Here are the key points of the matter.
Toxoplasmosis, how the infection occurs in humans
The protozoan Toxoplasma gondiiresponsible for the infection, completes a complex biological cycle which includes two phases. An intestinal one, exclusively in the cat and other mammals of its family, called definitive hosts. The cat becomes infected by ingesting raw or undercooked “infested” meat (for example by hunting infected mice), or by ingesting the oocysts, ie the “eggs” of the parasite, present in the environment. Toxoplasma reproduces in the intestine of the cat, which then excretes the oocysts in the environment with the faeces.
The other phase is extra-intestinal: in the tissues of both the definitive host and other animals, including humans (intermediate hosts). The contagion occurs, also in this case, through the consumption of raw or undercooked contaminated meat, or by ingestion of mature oocysts shed by the cat in the environment. Once ingested, the parasite is able to cross the intestinal wall and reach the tissues, muscles and brain above all, with the blood circulation. Cysts containing Toxoplasma form in the tissues.
Via cat feces in the environment
The infection can therefore be contracted in two ways. One way is through cats, by the fecal-oral route: that is, it is necessary to ingest the parasitic forms emitted by the cat with the feces. But these oocysts are never immediately infective (ie capable of causing an infection): they become so in the environment in a variable period of time but never less than 24 hours.
An infected cat sheds oocysts only once in its life and for a limited period which does not exceed 2 weeks. This means that, after this period, the cat can no longer infect.
It is true that the oocysts that are dispersed in the environment (gardens, vegetable gardens, parks, waters) are very resistant. Not only the cat litter is therefore a potential vehicle of contagion but also lettuce or strawberries, even if well washed. Just as it is also worth paying attention to the repotting of flowers or other gardening work done without gloves.
Through food (ingestion of raw or undercooked meat)
However, the infection can also be contracted through ingestion of the parasitic forms present in the tissues (meat) of the intermediate host animals (called “parasitic cysts containing bradyzoites”). The meats that most frequently contain this “dormant” form of the parasite are above all those of pigs, sheep, goats and, more rarely, other animals. These cysts can also be present in game meat.
It is estimated that the ingestion of raw or undercooked meats (reds are more at risk than whites) containing bradizioitis is responsible for 40-60% of infections.
Symptoms of toxoplasmosis infection in humans
At the time of infection, most people are asymptomatic or have only nonspecific symptoms: you have a reffective immune response, antibodies are produced, and the infection becomes “quiescent” (in a state of inertia).
In pregnancy: the risks and the test to do
The case of immunosuppressed people (the immune response is not effective) and pregnant women is different, due to the possible damage induced to the fetus (from damage to the retina to mental retardation). If the possibility of passing the parasite across the placenta increases as the pregnancy progresses, the risk of harm to the fetus decreases as the pregnancy progresses. In other words, the most important lesions occur in the fetus if the woman contracts the infection in the months preceding pregnancy (risk of miscarriage) and in the first trimester.
For this reason it is absolutely advisable to undergo the antibody test for toxoplasmosis. A test that is included in the TORCH panel, i.e. that group of infectious diseases which, due to the risks they may entail in pregnancy, are subjected to routine antibody tests (Toxoplasma gondii, Rubella, Cytomegalovirus and herpes simplex virus type 1). It is therefore worth undergoing the test in anticipation of pregnancy or within the first trimester.
Women who test negative they must be particularly scrupulous from the point of view of hygiene and nutrition.
Pregnant and with a cat at home? Yes you can
Living with an animal is not dangerous for a pregnant woman. The dogwhich does not transmit toxoplasmosis, can act as mechanical transporter of oocysts from the environment, just like any other family member or item brought into the house. If you live with a cat and its antibody test is negative, it can be helpful test the cat for toxoplasmosis. Interpreting the results is not difficult.
Test the cat for Toxoplasmosis
If the cat tests positive for IgG and IGM, it means that it has already passed the infection, he is immune and no longer eliminates oocysts. No problem, then.
If the cat is IgG negative and IgM positive it may mean that it has probably finished the oocyst elimination phase but it is advisable to maintain some hygiene rules and possibly perform PCR on faeces to search for the parasite.
Finally, if the cat is negative for IgG and IgM it means that the cat he is not immuneand since it has not yet been infected, it could become infected and later shed oocysts.
How to protect yourself from your cat
In these last two cases, it is advisable to observe some hygiene rules.
And that is to feed the cat with industrial food or in any case with meat that is always well cooked. Prevent it from feeding on small rodents or birds hunted in the garden.
Have the waste container changed and cleaned with boiling water at least once a day by another person. Remembering that oocysts never become infectious before 24 hours of their emission in the faeces.
Food and hygiene standards against “la Toxo”
On the nutrition front, pregnant is worth it avoid raw vegetables, even if washed with detergents or disinfectants because they do not kill the oocysts.
Avoid eating raw salamieven if seasoned or treated with other preservation methods other than cooking.
Avoid eating meat not cooked thoroughly. But also pay attention to contact with surfaces on which potentially contaminated food has been handled. For example, a cutting board on which the meats were cut. Particular caution should be used if the meats are imported from outside Europe (especially South America), where there are more aggressive variants of the parasite.
Avoid eating raw seafood and to drink unpasteurized milk (especially sheep and goats).
Engage in activities that involve contact with soil potentially contaminated without protection (gloves) or without subsequently washing hands thoroughly. For example, gardening activities or a picnic.
Toxoplasmosis in the world: how common is it?
In Europe, and in industrialized areas in general, a decline in seroprevalence is being observed. That is, people who have contracted the infection and therefore have antibodies against this parasite. For example, in France in the 1960s, seroprevalence in pregnant women was 80%, which fell to 44% in the early 2000s.
Italy, specifically, can be considered a medium prevalence country, where about 30% of women at the time of their first pregnancy have already contracted the infection and therefore already has antibodies that protect against this parasite.
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