Cat Toxoplasmosis is a silent disease with severe complications for both cats and humans all over the world.
In the USA, about 225000 cases of clinical toxoplasmosis occur annually, and more than 60 million people are thought to be infected.
About 25% of the population is exposed to Toxoplasmosis infection, In North America.
In Canada, 40 - 400 children are infected annually with Toxoplasma before birth.
As DR. provet cares about both human and animal health, he has decided to explain the cat Toxoplasmosis disease in detail through this article.
This article will address:
- What's cat toxoplasmosis?
- The life cycle of Toxoplasma gondii.
- Clinical signs of cat Toxoplasmosis.
- How to treat cat Toxoplasmosis?
- Prognosis of cat Toxoplasmosis.
- Prevention and control of Toxoplasmosis.
- The complications and the risk factors of Toxoplasmosis for human health.
What's cat toxoplasmosis?
Toxoplasmosis is a common parasitic disease caused by Toxoplasma gondii (T. gondii).
It can infect most warm-blooded animals, including humans and pets.
Cats are the main stage of the Toxoplasma gondii life cycle, however, this parasite rarely causes disease in them.
The life cycle of Toxoplasma gondii.
The only definitive hosts for T. gondii are cats.
When a cat eats raw meat or any other food contaminated by the Toxoplasma gondii cyst, the parasite is released into the cat’s digestive system and starts to reproduce, producing oocytes.
These oocytes are excreted in the feces of the infected cat 3 - 10 days after ingestion of infected tissues and continue for 10 - 14 days.
Some T. gondii from the infected meat penetrate deeply into the wall of the cat’s intestine and multiply as another form, called a tachyzoite.
Tachyzoites spread from the intestine to other parts of the cat's body and stimulate the cat’s immune system to make the parasite in a dormant stage.
In this stage, it forms cysts containing slowly grown Toxoplasma in muscles and brain, called a bradyzoite.
Humans and other animals are T. gondii intermediate hosts who become infected when eating oocysts.
After eating the oocysts, they go through sporulation for 1 - 5 days, then cause infection of the other animals.
Once an intermediate host ingests sporulated oocysts, the infection results in the formation of tissue cysts in different body tissues and remains in the intermediate host for life.
The ingestion of the cyst-containing tissue is the start of a new cycle in humans, cats, and another intermediate host.
Sometimes, Toxoplasma gondii tachyzoites can be excreted in the milk of infected cows and goats.
Clinical Signs of Toxoplasmosis
Often, cats infected with T. gondii don't show any signs of disease.
The disease severely affects cats only when its immune system is suppressed, such as cats with feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) and young kittens and so the common symptoms include:
Fever.
Diarrhea.
Lethargy, and fatigue.
Loss of appetite.
Infection of cat lung by T. gondii leads to pneumonia, causing difficulty breathing.
Liver Infections of the cat cause the appearance of a slightly yellowish color of both mucous membranes and the skin (jaundice).
Cat Toxoplasmosis can also affect the eyes and central nervous system (CNS), causing uveitis, and inflammation of the retina, or the space between the lens and cornea, producing:
Abnormal pupil size.
Blindness.
Lack of coordination.
Personality changes, circling, and seizures, head pressing, ear twitching,
High sensitivity to touch.
Difficulty chewing and swallowing food.
Loss of control over defecation and urination.
Diagnosis of cat toxoplasmosis
The diagnosis of cat Toxoplasmosis based on:
The history of the cat.
Clinical signs.
Laboratory tests depending on the detection of IgM, and IgG antibodies.
The presence of high levels of IgG in a healthy cat is a good indicator for its immunity against Toxoplasma gondii, and this cat is no longer a source of infection for the host; as no oocysts are excreted.
In contrast, the presence of high levels of IgM antibodies greatly suggests the active infection of the cat.
The absence of both 2 antibodies in the healthy cat indicates a great suggestion for the cat’s susceptibility to the infection, and oocysts shedding for up to 14 days post-infection.
Histological examination
The microscopic examination of tissue samples is required to detect the presence of tachyzoites and other certain changes of the tissues.
How to treat the cat Toxoplasmosis?
The treatment must start immediately to the diagnosis, and continue for a few days after the disappearance of the signs.
It mainly depends on clindamycin antibiotics.
In case of severe inflammation of CNS and eyes, corticosteroids should be given in combination with clindamycin.
Prognosis of the cat Toxoplasmosis
The prognosis for the infected cats differs according to:
The affected organs.
The interval time between infection and start of the treatment.
The initial responses to therapy.
Generally, the improvement of the symptoms within the first 2 - 3 days of treatment indicates a good prognosis of the disease.
The prognosis of cats with eye symptoms and CNS infection is more slowly,
When toxoplasmosis affects the cat’s liver or lungs, the prognosis is usually poor.
Prevention and control of cat toxoplasmosis
The prevention measures that should be considered include 2 steps
The first prevention step depends on prevention of the exposure of the cat to Toxoplasma gondii oocysts, through:
Avoid eating the cat's intermediate host, such as rodents.
Provide cooked food or commercially processed food to ensure the absence of oocysts.
The second prevention step depends on control the spreading of the oocysts present in feces into the environment, including:
Prevent the entry of the cat to the food storage rooms and the houses of the food-producing animals.
Frequent cleaning, and removal of feces from the litter before drying to avoid infection by inhalation of the aerosolized oocysts that spread in the area where the cat has defecated.
Wearing gloves during gardening to avoid contact with cat feces in the soil, and good handwashing afterward.
Avoid eating raw meat or unwashed vegetables and fruits handled by cat feces.
Complications and risk factors of Toxoplasmosis for human health
The chance of human infection via their cats is relatively small, as it requires a minimum of 24 hours for T. gondii oocysts in cat feces to sporulate and become infective.
Handling, scratching, or biting indoor cats with the previously mentioned prevention measures can't be sources of infection because the parasite isn't usually on their fur.
The high-risk factors are threatening pregnant women and immunodeficient individuals.
Pregnant women and their infants
In utero infection of pregnant women is a great problem as 1/3 - 1/2 of infants born to infected mothers, are infected.
Most mothers infected during pregnancy have no symptoms, and also most infected infants have no symptoms at birth
But many of these children are likely to have severe signs later in life, including blindness, loss of hearing, mental retardation, and death (in severe cases).
Immunodeficient individuals
In people who either have an immunosuppressive disease such as acquired immunodeficiency syndrome (AIDS) or undergo immunosuppressive therapy, toxoplasmosis may cause some complications, including:
Enlargement of the lymph nodes.
Eye and central nervous system disturbances,
respiratory disease,
and heart disease.
In these patients, especially those with AIDS, relapses of the disease are common, and the mortality rate is high.
Finally, cat Toxoplasmosis is a serious disease that must be considered to be perfectly prevented to avoid further risk factors for human health.
Written by: Dr. Mai Foda