Toxoplasmosis: A Nasty Parasite
Toxoplasmosis is a disease often associated with cats. However, it should be noted that dogs, and even humans, are also not immune to this parasite.
Toxoplasmosis is caused by the Toxoplasma gondii parasite. Also known as Toxoplasma gondii, and T. gondii, this is a single-celled and zoonotic parasite, related to coccidia, which are single-celled parasites. It is usually spread through contaminated soil, or when an animal, such as a dog or cat, eats infected prey such as rodents, birds, or other small animals.
What is Toxoplasmosis?
The first stage in the life cycle of T. gondii begins when a cat eats an infected rodent or any other animal carrying the parasite’s eggs, or oocysts, in its intestine. The cat then sheds millions of oocysts into its environment through its feces, where they can remain viable for up to 18 months if kept in moist conditions. These oocysts are the form of T. gondii that’s most likely to infect humans; however, it can also be transmitted by eating undercooked or raw meat from an infected animal, or through organ transplants using infected donor organs.
When a human or other intermediate host ingests the oocyst containing T. gondii, it undergoes a process known as excystation, which involves breaking down the cell wall and releasing sporozoites into the host’s intestine. The sporozoites travel from the intestine to other parts of the body via the bloodstream and lymphatic system, where they can form tissue cysts that remain dormant for years.
This tissue cyst stage is especially dangerous for pregnant women, as it can be passed to the developing fetus and cause severe birth defects. During pregnancy, it’s very important to avoid contact with cat litter and undercooked meats in order to minimize the risk of infection.
However, once tissue cysts are formed, they cannot be eliminated from the body and will remain dormant until their immune system becomes weakened. In some cases, these cysts can flare up and cause symptoms such as fever and fatigue, which require medical attention.
Toxoplasmosis and Dogs
For dogs, toxoplasmosis generally only causes mild clinical signs such as fever, anorexia, lethargy, and breathing issues. It can also cause fever, stomach pain, vomiting, decreased appetite, enlarged lymph nodes and neurological symptoms in dogs. However, in young puppies or dogs with compromised immune systems, toxoplasmosis can cause severe symptoms such as seizures and even death.
Toxoplasmosis will typically affect a dog’s gastrointestinal system, respiratory system, and nervous system. The medication used to treat toxoplasmosis in dogs is usually a combination of antibiotics such as Clindamycin and Tetracycline. Other medications, such as Sulfadimethoxine, may also be prescribed if the infection is severe or not responding to the antibiotics. Additionally, anti-parasitic medication may also be prescribed. It’s important to follow all of your Austin veterinarian’s instructions when treating toxoplasmosis in dogs to help ensure your pet’s recovery. Left untreated, it can be fatal.
It is possible for dogs to be carriers of toxoplasmosis without showing any symptoms. Pregnant dogs can pass the infection on to puppies they’re carrying, so it’s very important to get your dog tested if you suspect they may have it.
Symptoms in Dogs
Healthy adult dogs may not show any signs of toxoplasmosis, since their immune systems are capable of controlling its spread. Dogs with any type of weakened immunity, based on their age or health conditions, as well as puppies who have less developed immune systems face a higher risk for developing these symptoms, which can include:
- Difficulty breathing or coughing
- Muscle weakness
- Decrease in appetite
- Eye inflammation
- Seizures, tremors, or other neurological symptoms
It’s important to take precautions, such as keeping dogs away from areas where infected cats may have left feces, avoiding feeding raw or undercooked meat, and washing hands and surfaces before and after contact with any animal, regardless if they’re healthy or ill.
If your dog shows any of these symptoms, or any other signs of potential illness, contact your Austin veterinarian for diagnosis and treatment.
Toxoplasmosis and Cats
Toxoplasmosis can be contracted by cats through the ingestion of infected rodents, birds and other small animals, as well as contact with contaminated soil or litter boxes and by eating raw or undercooked meat.
In cats, T. gondii reproduces in the small intestine and is then shed in the feces for up to two weeks after infection. Newly exposed cats will often shed oocysts in three to ten days and continue shedding them up to fourteen days. Once in the environment, the oocysts form spores (sporulate) and then they become infectious anywhere between one to five days.
If left untreated, toxoplasmosis can cause serious damage to your cat’s organs and pose a serious risk to their health. Cats can experience neurological problems, pneumonia, and even death in severe cases. It’s particularly dangerous for cats that have not been vaccinated against it.
It should be noted that both indoor and outdoor cats are at risk of contracting the disease. Toxoplasma gondii is a protozoan parasite that cats act as the definitive host for, meaning they are the only species capable of passing toxoplasmosis oocysts in their feces.
Therefore, it’s important to be sure that cats receive proper vaccinations against it and regular veterinary check-ups early on.
Symptoms in Cats
The most common symptoms of toxoplasmosis, in regards to cats, includes:
- Weight loss
- Difficulty breathing
- Eye inflammation
- Respiratory distress
Other symptoms are possible depending upon whether it’s an acute or chronic infection, and where the parasite is located in the body. Fortunately, toxoplasmosis is treatable with medication when diagnosed early. To help keep cats safe,keep them indoors and regularly provide flea and tick prevention treatments. Additionally, cats should only be fed cooked or dried foods to help reduce their risk of toxoplasmosis.
The type of medication prescribed by a veterinarian will depend on the severity of the infection. Generally, antibiotics such as tetracycline and sulfonamides are used to treat T. gondii infections in cats. Other medications such as anti-parasitic drugs may also be prescribed.
How Does Toxoplasmosis Affect Humans?
Unwashed fruits and vegetables are also potential sources of the parasite, as well as raw or undercooked meat, especially pork, lamb, and venison. Toxoplasmosis can cause health problems in people with weakened immune systems, such as pregnant women, people who have HIV/AIDS, and some cancer patients. It can also cause flu-like symptoms in otherwise healthy people. Toxoplasmosis can also cause serious eye infections that may result in vision loss or blindness.
As mentioned above, if toxoplasmosis is contracted during pregnancy, it can cause serious health problems in the unborn baby, such as birth defects and even miscarriage. It’s highly recommended that pregnant women avoid contact with cat litter boxes, due to the risk of transmission from cats.
If you think you may have toxoplasmosis, see a doctor immediately for diagnosis and treatment. Treatment usually consists of prescription medications that help fight off the parasite. Always wash your hands after handling raw meat, and washing food items before eating them, and avoid contact with cat feces.
Basic Precautions and Hygiene
The following precautions and hygiene measures can greatly reduce the risk of human infection:
- All meat should be cooked thoroughly at a temperature of roughly 160-180°F.
- Always wash hands, utensils, and any surfaces after handling raw meat.
- Wash all vegetables carefully and thoroughly.
- Wear gloves while gardening, especially if you’re working near soil that ay be contaminated by cat feces.
- If you have cats, empty their litter boxes daily, remove the litter carefully, and disinfect with boiling water. It can take more than 24 hours for oocysts passed in the feces to transform into becoming infective. If you sanitize your litter box daily, and even if your cat is removing oocysts in their feces, he/she will not become infectious once the litter is changed.
- Prevent your cats from hunting prey and never feed them raw or undercooked meat.
- Cover children’s sandboxes to keep cats from using them as litter boxes.
If you suspect that your pets may have contracted toxoplasmosis, or want to learn more about it, please reach out to ATX Animal Clinic. We offer full health screenings that can help determine if your loved one is affected by this disease, as well as core vaccines to help prevent it.