Pregnant and Toxoplasmosis

1. Toxoplasma Gondii is a very common parasite that can be very dangerous for pregnant women. Although the mother may have few or no symptoms of infection with Toxoplasma, the parasite can cause serious damage to the unborn child. Symptoms range from various birth defects to spontaneous abortion. The risk of infection of the fetus is particularly high at the end of a pregnancy, although the symptoms are often milder. At the beginning of a pregnancy, the risk of infection is small, but the symptoms are often more severe.

Toxoplasma

1. Toxoplasma Gondii is a parasite that can infect humans through the gastrointestinal tract. The parasite mainly occurs on raw or undercooked meat and unwashed vegetables. Immunity occurs after infection with Toxoplasma, but the infection remains latent. Disease symptoms in healthy people are mild, but infection during pregnancy can lead to miscarriage or birth defects. Therefore, pregnant women are advised to avoid risk products.

History

1. Toxoplasma was first found in a rodent in 1908. In 1923, a human infection with Toxoplasma was also diagnosed, but it was only discovered in 1939 that toxoplasmosis could lead to birth defects. In the late 1960s, after the discovery that felines spread the parasite, steps were taken to warn pregnant women against Toxoplasma. In 1974 it became clear that toxoplasmosis can cause the most damage in the first two trimesters of pregnancy and that women who have been infected before pregnancy do not transmit the infection to the fetus.

Origin of Toxoplasma

1. Toxoplasma has a sexual cycle and an asexual cycle.

Sexual cycle

1. Only in feline animals does the sexual cycle of Toxoplasma proceed. Felines can become infected by eating contaminated prey. Oocysts develop in the small intestine and come out through the stool over a period of one to three weeks. After a few days, these oocysts become infectious and can then remain for more than a year. Cats become immune to the parasite after infection and often stop shedding oocysts after the initial infection, unless they are re-exposed to Toxoplasma years later or their immune systems are compromised. This makes young cats in particular a risk for Toxoplasma.

Asexual cycle

1. In other animals, but also in humans, an asexual cycle takes place in which after ingestion the oocysts divide into a random cell. Over time, tissue oocysts develop, which contain several parasites. These can remain in the body for life.

Toxoplasma Prevention

1. Toxoplasma oocysts reside in cat feces or other feline and contaminated soil. Water can also be contaminated through contaminated soil. Warm-blooded animals that come into contact with contaminated soil can then also become infected themselves. Mainly pigs, sheep and goats are often infected, but cattle, chickens, rabbits, horses, pigeons and hares can also be infected. It does not occur in fish, because fish are not warm-blooded. Toxoplasma has been found in crustaceans and shellfish, which remains in these animals due to the water filtering effect.

Inactivation of Toxoplasma

1. The tissue oocysts can be killed by gamma radiation, acidification, salting, heating and freezing.

Radiation

1. Gamma radiation from a dose of 1.0 kGy can kill the oocysts.

PH

1. Toxoplasma cannot survive in an too acidic environment. At a pH lower than 4, the tissue oocysts are inactivated. Products such as sauerkraut or sufficiently acidified yogurt with a pH below 4 cannot therefore cause toxoplasmosis.

Salt

1. Tissue oocysts die at a salt concentration greater than six percent. In meat, a salt concentration higher than 1.1 percent is sufficient. Some salted raw meats, such as raw ham, cannot cause toxoplasmosis because of this.

Temperature

1. Toxoplasmosis is killed by freezing for two days at -20 degrees Celsius or by heating above 70 degrees Celsius.

Immunity

1. Once infected with Toxoplasma, the tissue cysts will often remain for life. The body produces antibodies against the tissue cysts that persist as long as tissue cysts are present. The continuous production of these antibodies makes a person immune to toxoplasmosis and an infection cannot revive and lead to symptoms of disease. Women who are pregnant and immune to Toxoplasma will not easily infect the baby because of the antibodies already present. Yet there are cases where this does happen, for example in people with a weakened immune system.

Chance of toxoplasmosis

1. The chance of contracting an infection during your lifetime is quite high. Four in ten Dutch people have been infected with Toxoplasma in their lifetime. Because symptoms of disease are not or hardly present in healthy people, most people do not know that they are infected. Most people get an infection when they are between 25 and 44 years old. This means that many women trying to conceive for the first time have never contracted an infection and are not yet immune to toxoplasmosis. As a result, as many as 60 percent of women who become pregnant for the first time are at risk of contracting toxoplasmosis.

Incubation time

1. After ingesting oocysts via contaminated food, for example, it takes one to two weeks for tissue cysts to develop. These can arise anywhere, but the most sensitive organs are the brain, retina, muscles and heart. The incubation period for toxoplasmosis varies from 10 to 23 days.

Symptoms of toxoplasmosis

1. In healthy people, the symptoms of toxoplasmosis are mild and many will not even notice they have contracted an infection. Symptoms include fever and skin rash, but also the development of other personality traits, a reduced IQ and a reduced psychomotor capacity are symptoms. In people with an immune disease, the symptoms can become severe. The same applies to an infection of an unborn child, especially if the infection develops during the first trimester of pregnancy. During this period of pregnancy, symptoms such as hydrocephalus, arteriosclerosis in the brain, mental retardation, brain disorders, eye disorders and deafness can occur. Some of these pregnancies will end in miscarriage. The risk of infection of the fetus if the mother is infected in the first trimester is small. At a gestational age of 10 weeks, the chance is about six percent. This increases to more than eighty percent at a gestational age of 38 weeks. In the last trimester the symptoms are less severe and are limited to fever, skin rash, clotting abnormalities in the blood, anemia, enlargement of the liver and spleen or an eye infection. When infected in this final phase, more than half of the children do not show any symptoms. These children often develop symptoms such as eye abnormalities or blindness at a later age. Finally, the severity of the symptoms may depend on the Toxoplasma strain. Strains that occur in Brazil often have a more serious course than strains that occur in the Netherlands.

Screening

1. A screen to determine if a person has ever been infected with Toxoplasma is easily performed by determining the antibodies in the blood. In the Netherlands there is no prenatal screening for the presence of Toxoplasma, but the choice is made to properly inform pregnant women on how best to limit risks. In other countries, such as France and Austria, pregnant women are screened. In Denmark, children are screened after delivery.

Risk products

1. Risk products for Toxoplasma consist mainly of raw meat and in particular pork, mutton and goat meat, but also beef, chicken, rabbit, horse, pigeon, hare and crustaceans and shellfish are also a risk. In addition, one must be careful when drinking raw milk. Raw vegetables and fruit can also be infected with tissue cysts because the products can be contaminated with contaminated soil. In addition to these risk products, one must also be careful of contact with contaminated soil or infected animals. For example, pregnant women who work in the meat processing industry run an increased risk. Activities such as gardening or changing the litter box can also lead to toxoplasmosis.

Products without risk

1. Fish does not pose a risk for Toxoplasma, because the parasite only multiplies in warm-blooded animals. It also appears that working as a veterinarian does not involve an increased risk.

Recommendations

1. To prevent toxoplasmosis during pregnancy, the following precautions are recommended: