Protozoa: what they are, diseases and how to treat them

Protozoa are simple microorganisms, since they consist of only 1 cell, and are responsible for infectious diseases that can be transmitted from person to person, as in the case of Trichomoniasis, for example, or through the bite or bite of insects, as in the case of Leishmaniasis and Chagas Disease.

Diseases transmitted by protozoa can be prevented by simple measures, such as hand washing before and after preparing food or having contact with animals, using condoms during sex and wearing long-sleeved pants and blouse or repellent in areas at risk malaria, for example.

Diseases caused by protozoa

1. Toxoplasmosis

Toxoplasmosis is an infectious disease caused by the protozoan Toxoplasma gondii , which has cats as its definitive host, and humans as an intermediate host. Thus, people can be infected by this parasite through the ingestion of Toxoplasma gondii cysts present in soil, water or food, direct contact with the feces of infected cats or through mother-child transmission, also called transplacental, which it happens when the pregnant woman acquires toxoplasmosis and does not do the appropriate treatment, and the parasite can pass through the placenta and infect the baby.

The diagnosis of Toxoplasmosis is made mainly through immunological tests that indicate the concentration of antibodies against the parasite circulating in the blood. In addition to immunological tests, the doctor must take into account the symptoms presented by the patient, although the symptoms are often similar to other parasites.

Main symptoms: In most cases, toxoplasmosis is asymptomatic, however in pregnant women and people with compromised immune system, symptoms can appear between 5 to 20 days according to the form of contagion. The main symptoms related to Toxoplasmosis are swelling of the neck, headache, red spots on the body, fever and muscle pain. Know how to recognize the symptoms of toxoplasmosis.

How the treatment is done: The treatment for Toxoplasmosis is done with the objective of eliminating the parasite from the organism, being usually recommended by the doctor the use of medications, such as Pyrimethamine associated with Sulfadiazine. During pregnancy, in the event of a diagnosis of toxoplasmosis, it is important that treatment be carried out quickly to avoid fetal malformations and complications during pregnancy. Understand how treatment for toxoplasmosis is done.

2. Leishmaniasis

Leishmaniasis is a parasitosis caused by the protozoan of the genus Leishmania which, according to the species responsible for the infection, can cause symptoms ranging from mild to severe. One of the species most frequently found in Brazil is Leishmania braziliensis , which is usually related to more serious clinical manifestations.

The transmission of Leishmania species occurs through the bite of the mosquito of the genus Lutzomyia , popularly called the straw mosquito, which when biting people, for example, deposits the parasite that was located in their digestive system. According to the species and symptoms presented by the patient, leishmaniasis can be classified into cutaneous or cutaneous leishmaniasis, mucocutaneous leishmaniasis and visceral leishmaniasis, each presenting specific characteristics. See how to identify visceral and cutaneous Leishmaniasis.

Main symptoms: In the case of cutaneous leishmaniasis, the initial symptoms usually appear between two weeks and three months after infection by the protozoan, with the appearance of one or more nodules at the site of the mosquito bite, which can progress to an open wound and painless in a few weeks.

In the case of mucocutaneous leishmaniasis, the lesions are more serious and progress quickly to open lesions involving the mucous membranes and cartilage, mainly the nose, pharynx, and mouth. These injuries can result in difficulty in speaking, swallowing or breathing, which can increase the risk of infection and result in death, for example.

In visceral leishmaniasis, on the other hand, the symptoms have a chronic evolution and there is usually frequent fever, enlarged spleen and liver, anemia, weight loss and edema, and should be treated quickly, since people with this type of leishmaniasis can progress quickly to cachexia and, consequently, death.

How the treatment is done: The treatment for leishmaniasis is done when the initial lesions are very large, multiply or result in debilitating symptoms, being indicated the use of Pentavalent Antimonials, such as Amphotericin B, Pentamidine and Aminosidine, for example, which should be used according to the type of leishmaniasis and the doctor's guidance.

3. Trichomoniasis

Trichomoniasis is an infectious and sexually transmitted disease that is caused by the protozoan Trichomonas sp ., Being the species most commonly found is Trichomonas vaginalis . Infection with this parasite can happen in both men and women, causing symptoms similar to urinary infections.

Main symptoms: In women, the symptoms of trichomoniasis take about 3 to 20 days to appear, there may be a yellowish-green discharge and a strong odor, pain during sexual intercourse, pain when urinating and increased urge to pee. In men, the main symptoms are clear, viscous and sparse discharge and discomfort when urinating. Learn how to identify Trichomoniasis.

How the treatment is done: The treatment for Trichomoniasis is done with the use of antibiotics according to the medical advice, being usually indicated the use of Tinidazole or Metronidazole, for example. It is important that both the infected person and his partner undergo treatment for trichomoniasis even if there are no symptoms.

4. Chagas disease

Chagas disease, also known as American trypanosomiasis, is an infectious disease caused by the parasite Trypanosoma cruzi . This disease is transmitted through the bite of an insect popularly known as a barber, which immediately after biting the person, defecates, releasing the parasite, and when the person scratches the place, it ends up spreading the protozoan and allowing it to enter the body.

Although the bite of the barber is the most common form of transmission of the parasite, Chagas disease can also be acquired through transfusion of contaminated blood, from mother to child during pregnancy or childbirth and through the consumption of contaminated food by the barber or its excrement, mainly sugar cane and açaí. Learn more about Chagas disease.

Main symptoms: The symptoms of chagas disease vary according to the host's immunity, and may be asymptomatic, in which the parasite stays in the body for years without causing symptoms, or have symptoms that vary from mild to severe according to the amount of parasites in the person's body and immune system.

The main symptoms related to Chagas' disease are fever, edema at the bite, enlarged liver and spleen, swollen and painful lymph nodes and general malaise. In addition, cardiac involvement is common, leading to an enlarged heart, and swelling of the eyelids.

How the treatment is done: The treatment for Chagas disease is not yet well established, however it is usually indicated that patients with Chagas are treated with the use of Nifurtimox and Benzonidazole.

5. Giardiasis

Giardiasis is a parasitosis caused by the protozoan Giardia lamblia , which is the only species of the genus Giardia capable of infecting and causing symptoms in people. This disease is more common in children and can be transmitted through the ingestion of Giardia lamblia cysts present in contaminated water, food or environment, in addition to direct contact with contaminated people, this form of transmission being common in places where there are many people and does not have adequate sanitary conditions. Understand more about what giardiasis is and how it is transmitted.

Main symptoms: The symptoms of giardiasis appear 1 to 3 weeks after contact with the protozoan and are mainly intestinal, with abdominal cramps, increased production of intestinal gases, poor digestion, unintentional weight loss and diarrhea that can be mild and persistent or intense.

How the treatment is done: Treatment for giardiasis involves the use of antibiotics and antiparasitic agents, such as Metronidazole, Secnidazole, Tinidazole or Albendazole, which should be used as directed by the doctor. In addition, due to diarrhea, it is important that the person drinks plenty of fluids during treatment in order to prevent dehydration, which is common in these cases.

In more severe cases, when diarrhea is intense and persistent, it is recommended that the person be referred to the nearest health center or hospital to receive serum directly into the vein and thus dehydration can be avoided.

6. Amoebiasis

Amoebiasis is a very common infectious disease in children, is caused by the parasite Entamoeba histolytica and is transmitted mainly through ingestion of cysts present in water or food contaminated with feces. When the cysts enter the body, they remain lodged in the wall of the digestive tract and release the active forms of the parasite, which reproduce and go to the person's intestine, causing digestive symptoms. Learn more about amebiasis.

Main symptoms: Entamoeba histolytica can remain in the body without causing symptoms for years, however it is more common that around 2 to 4 weeks after contagion the symptoms begin to appear. The main symptoms related to amebiasis are abdominal discomfort, diarrhea, feeling sick, nausea, excessive tiredness and the presence of blood or secretion in the stool.

How the treatment is done: The treatment of amebiasis is simple and should be done with Metronidazole according to the doctor's guidance. Despite being an easy-to-treat parasitosis, it is important to start as soon as the first symptoms appear, as Entamoeba histolytica is able to pass through the intestinal wall and spread through the bloodstream, reaching other organs and causing more serious symptoms..

7. Malaria

Malaria is caused by the bite of the female mosquito of the genus Anopheles infected by the parasite of the genus Plasmodium spp . The main species of the parasite found in Brazil are Plasmodium malariae , Plasmodium falciparum and Plasmodium vivax . This parasite, when entering the body, goes to the liver, where it multiplies, and then reaches the bloodstream, being able to destroy red blood cells, for example.

Despite being infrequent, malaria transmission can also happen through transfusion of contaminated blood, sharing contaminated syringes or accidents in the laboratory, for example.

Main symptoms: The malaria incubation period, which is the time between contact with the disease-causing agent and the appearance of the first symptoms, varies according to the species of protozoan. In the case of P. malariae , the incubation period is 18 to 40 days, that of P. falciparum is 9 to 14 days and that of P. vivax is 12 to 17 days.

The initial symptoms of malaria are similar to those of other infectious diseases, with malaise, headache, tiredness and muscle pain. Usually these symptoms precede the characteristic symptoms of malaria, which are generally related to the parasite's ability to enter and destroy red blood cells, such as fever, sweat, chills, nausea, vomiting, headache and weakness.

In the most severe cases, especially when the infection occurs in children, pregnant women, non-immune adults and people with compromised immune systems, there may be seizures, jaundice, hypoglycemia and changes in the state of consciousness, for example.

How the treatment is done: To treat malaria, the doctor usually indicates the use of antimalarial drugs, which are provided free by SUS, according to the type of Plasmodium , severity of symptoms, age and immune status of the person. Thus, the use of Chloroquine, Primaquine or Artesunate and Mefloquine, for example, may be recommended. Learn more about treatment for Malaria.