Parasitic Zoonoses
When a parasite that usually resides inside or on an animal’s body causes a disease in human beings, the disease caused by it is known as parasitic zoonosis. There are many types of parasites that reside in and on animals’ bodies. Pet animals like dogs and cats also have them and can become an important source of transmission of these parasites to humans if not taken good care of.
Toxoplasmosis
This disease is caused by Toxoplasma gondii. It has multiple routes of transmission including vertical and horizontal routes. It has a heterogeneous life cycle (involving different species) and can infect most warm-blooded animals. It is prevalent globally and all animals and birds may get infected by Toxoplasma gondii. Felines like cats are important reservoirs of this disease. Felines are capable of shedding oocysts in the feces.
Infection rates are higher in hot, humid climates and lower altitudes because the oocysts can survive in such climates. The transmission can be congenital, by blood transfusion or organ transplantation. The transmission can be food-borne and zoonotic.
Cats play an important role in the zoonotic transmission of toxoplasmosis. They usually get infected after hunting rodents or birds. This parasite is then transmitted from cat-faeces in the form of oocysts to the environment. Younger kittens shed more oocysts compared to adult cats.
People can become infected by accidental ingestion of oocysts after cleaning cat litter or by coming in contact with infected cat feces. Accidental ingestion of oocysts from contaminated soil or water can also happen. Congenital transmission is also common when it comes to toxoplasma.
In humans-
Healthy people usually do not show symptoms because of active immune systems.
- In the cases where symptoms show, they are usually mild and flu-like
- After recovery, the parasite remains in the person in an inactive state and may re-activate in case the person gets immunocompromised.
- Pregnant women may undergo miscarriage or have a stillbirth. Children can also be born with congenital toxoplasmosis.
In animals-
Most animals do not show signs of illness.
- Young animals may suffer from interstitial pneumonia, myocarditis, hepatic necrosis, meningoencephalitis, lymphadenopathy and myositis.
- Corresponding signs may include fever, cough, diarrhea, dyspnoea, icterus, seizures and death.
Indirect Haemagglutination Assay, Fluorescent Antibody Assay, and ELISA are some of the tests that can be performed. CSF may be analyzed for the presence of anti-T. gondii antibodies. Parasites may or may not be isolated from blood.
Food should be cooked properly at recommended temperatures. Sample meat should not be consumed without cooking. Whole meats should be cooked at 145 degrees Fahrenheit, ground meat must be cooked at 160 degrees Fahrenheit and poultry meat should be cooked at 165 degrees Fahrenheit. Fruits and vegetables should be washed thoroughly and peeled. Unpasteurized milk should not be consumed. Avoid drinking water from unknown sources. Outdoor sandboxes must be covered and cat litter boxes must be cleaned carefully. Try to keep your pet cats indoors.