Toxoplasmosis In Tame or Bold Foxes

Toxoplasmosis is a well-documented yet often overlooked zoonotic disease—one that can affect both humans and animals. It can have serious consequences for both wildlife and human health. While it is commonly associated with domestic cats, which are considered definitive hosts, wild animals—including foxes—can also carry the parasite. A recent case we encountered underscores the hidden risks associated with foxes that appear unusually tame, as well as the ethical and practical challenges involved in managing their welfare.

The Case of a Tame Wild Fox

After seeing a video online of a young wild fox displaying unusually calm behaviour, we reached out to the wildlife rescue with our concerns. Despite appearing outwardly healthy, the fox’s behaviour was far beyond typical habituation. Given our extensive experience with both veterinary surveillance and fox behaviour, we recognised that this could be more than just a habituated or imprinted fox. One possible explanation was toxoplasmosis.

Releasing such a fox is not an option. On top of this, a fox with active toxoplasmosis could pose a risk to other animals and even people. The only responsible course of action was to test for the disease, though the cost is significant—around £600 for confirmation and initial tests. The rescue decided to get the fox tested, the results were received recently and confirmed our suspicions: the fox tested positive for toxoplasmosis.

Why Toxoplasmosis is a Serious Concern

Toxoplasma gondii is a parasitic protozoan that can manipulate animal behaviour, often making infected animals bolder, more reckless and fearless of predators, humans or novel situations. This is well-documented in rodent studies, where infected rats lose their natural fear of cats. In foxes, toxoplasmosis can manifest in ways that make them appear docile and unusually tolerant of human presence, almost like a loving pet. They are easily misidentified as habituated or food-tamed foxes.

The real danger is that a fox appearing ‘tame’ may not be an animal seeking human companionship, but rather one suffering from a neurological infection. Such foxes cannot be released, as they are more likely to get into trouble—approaching roads, people, and other animals without appropriate wariness. Additionally, toxoplasmosis is a zoonotic disease, meaning it can be transmitted to humans and other animals, posing significant risks.

Transmission of Toxoplasmosis

Toxoplasmosis can be transmitted in several ways. In wildlife, the primary mode of transmission is through consumption of infected rodents, which are often carriers of the parasite. Foxes can also contract toxoplasmosis through exposure to contaminated faeces or urine from infected animals, especially when caching food supplies. Additionally, bites from infected individuals can spread the disease, particularly if the fox is in direct contact with the saliva or blood of another infected animal.

Another form of transmission is congenital toxoplasmosis, where the infection is passed from mother to offspring during pregnancy. This can result in the parasite affecting the brain of young foxes, leading to neurological changes that may alter their behaviour, including increased tameness or altered fear responses. This form of transmission can complicate efforts to identify and manage infected animals, as symptoms may not appear until the fox reaches maturity.

Symptoms of Toxoplasmosis in Foxes

While it is easy for fox feeders, wildlife rescuers and rehabilitation centres to identify a sick-looking foxes with toxoplasmosis—a fox that has had the parasite long enough it has begun to cause serious issues—healthy foxes suffering from toxoplasmosis are not so easily identified, as people wrongly attribute good physical health to a lack of possible infection.

While these foxes may not appear sick, they can still pose a risk to other animals, humans, and staff. By recognising the early signs of toxoplasmosis, rescuers can help prevent the unnecessary release or rescue of infected foxes, ensuring proper testing and precautions are taken.

Healthy foxes with toxoplasmosis, may display the following:

Unusually calm or fearless behaviour: Infected foxes show no fear when approached by humans or animals and are unbothered by loud noises or sudden movements.
Extreme curiosity and risk-taking: These foxes demonstrate confidence and curiosity in novel situations, such as approaching unfamiliar objects or people, and may take dangerous risks like wandering into roads or open areas.
Apparent tameness without prior habituation: Foxes may appear unusually friendly, approaching strangers or new environments without the gradual bonding process typical for wild animals.
Soft, welcoming eyes and prolonged eye contact: Toxoplasmosis can cause changes in the eyes, making them seem 'soft' and 'inviting', similar to that of a pet.
Feeding difficulties or texture aversions: Infected foxes may reject certain foods or show dislike for specific textures, which can indicate neurological effects from the parasite.

More severe signs of toxoplasmosis include:

Severe neurological symptoms such as seizures, tremors, or lack of coordination, resulting from the parasite affecting the brain and nervous system.
Loss of motor control, making it difficult for the fox to move or respond appropriately to stimuli.
Severe disorientation or a lack of awareness of surroundings, which may cause the fox to appear confused or unresponsive. Seemingly tame foxes can suddenly snap.
Difficulty eating or swallowing, sometimes leading to malnutrition or dehydration as the fox may struggle to feed or show a marked decrease in appetite.
Sudden and extreme changes in behaviour, such as heightened aggression or extreme tameness, both of which are atypical.
Blindness or eye abnormalities, which can occur when the parasite affects the eyes, leading to a loss of vision or visible changes in eye appearance.

Risks to Humans in Wildlife Rehabilitation

Toxoplasmosis is a zoonotic disease (transmissible to humans), posing risks to wildlife carers, especially those handling foxes, rodents, or carnivores. Risks include:

Exposure to infected faeces, urine, or saliva: Parasite oocysts shed in waste can contaminate enclosures and surfaces.
Bites & scratches from infected animals: Direct transmission through wounds.
Aerosols & cross-contamination: Dry faecal matter can spread in dust, increasing risk of accidental inhalation or ingestion.
Higher risk for vulnerable individuals: Pregnant people and those with weakened immune systems are at greater risk of severe illness, birth defects, or complications.

Symptoms of Toxoplasmosis in Humans:

Flu-like illness: Fever, muscle aches, fatigue, and swollen lymph nodes.
Neurological symptoms: Headaches, confusion, poor coordination, or seizures in severe cases.
Eye infections: Blurred vision, inflammation, and light sensitivity.
Severe complications: For pregnant individuals, infection can cause miscarriage, stillbirth, or congenital disabilities in the baby. Those with weakened immune systems (e.g., due to HIV, chemotherapy, or organ transplants) are at risk of severe illness, including brain inflammation (encephalitis).

Precautions in Rehabilitation Settings:

Always test tame or neurologically affected foxes before considering release or mixing with other animals.
Use PPE (gloves, masks, hand hygiene) when handling potentially infected animals or cleaning enclosures.
Quarantine new intakes and suspected cases, and properly dispose of contaminated bedding and waste.
Educate staff and volunteers on early detection and safe handling procedures to prevent spread.

By recognising these signs, rescuers can help prevent the spread of the parasite, protect staff from potential exposure, and ensure that foxes receive proper care before being released or integrated into new environments. Early identification and testing are crucial in protecting both the foxes, staff, and surrounding wildlife.

What Happens Next or the Rescued Fox?

The infected fox will require treatment and additional testing before any rehoming possibility can be considered. Unfortunately, there are very few places that can take in a fox with these health concerns, as permanent placements for foxes are already scarce. If a suitable home cannot be found, humane euthanasia may be the only ethical outcome.

Additionally, there is now a potential risk to the rescuers, so a biocontainment plan will be put into place to ensure the safety of the staff and animals. Should bites occur from a wild animal with suspected toxo (e.g. tame behaviour), seeking immediate medical attention in such situations is crucial, as early intervention can reduce risks to human health.

Decontamination After Exposure

Toxoplasmosis is a resilient zoonotic disease, and its oocysts can persist in the environment for months if not properly managed. After admitting a fox with suspected or confirmed toxoplasmosis, thorough decontamination is essential to prevent the spread of infection to other animals and staff.

Cleaning & Disinfection

Use boiling water or steam: T. gondii oocysts are highly resistant to most disinfectants but can be destroyed by exposure to temperatures above 70°C (158°F). Steam cleaning enclosures, bedding, and feeding areas is highly effective.
Disinfect with ammonia or bleach: A 10% ammonia solution or 1:10 bleach solution (sodium hypochlorite) can kill oocysts, but surfaces must stay wet for at least 10–20 minutes before rinsing.
Use disposable or washable bedding: Burn or dispose of contaminated straw, hay, or fabric bedding, or wash fabric at 60°C or higher with detergent.

Waste Management

Dispose of faeces and soiled bedding properly: Oocysts shed in faeces take 1–5 days to become infectious, so immediate disposal reduces risk.
Bag and bin waste: Place waste in double-bagged sealed containers before disposal. Avoid composting, as oocysts can survive in soil for months.

Hand & Personal Hygiene

Wear PPE (gloves, masks, and aprons): Prevent direct contact with faeces, urine, and contaminated materials.
Wash hands thoroughly: Use soap and hot water immediately after handling infected animals or cleaning their enclosures. Alcohol-based sanitizers are not effective against oocysts.
Change clothing and footwear: Wash contaminated clothes separately at high temperatures (60°C+) and disinfect boots using ammonia or bleach solution.

Environmental Control & Isolation

Quarantine infected or suspected cases: Keep affected foxes in a separate, easily disinfected area.
Limit access to enclosures: Restrict entry to necessary staff and use designated tools that remain in that area.
Control rodent and stray cat populations: As both are major vectors of toxoplasmosis, ensure they do not have access to food stores or rehabilitation enclosures.

Education & Monitoring

Train staff and volunteers: Ensure everyone understands the risks, symptoms, and transmission pathways of toxoplasmosis.
Monitor for symptoms in other animals: If an animal in care develops neurological signs or unusual behaviour, consider testing for toxoplasmosis.

By following strict hygiene and biosecurity measures, wildlife rescues can minimise risk and maintain a safe working environment.

Treatment in Humans and Animals

There is no cure for toxoplasmosis, so treatment focuses on managing symptoms and limiting parasite replication. In foxes, clindamycin may be used, but effectiveness is uncertain, and humane euthanasia is often advised on welfare grounds.

In humans and pets, antiparasitic medications are prescribed only in severe cases or for immunocompromised individuals:

Humans

Healthy individuals: Usually recover without treatment. Severe cases may require pyrimethamine, sulfadiazine, and folinic acid.
Pregnant women: Spiramycin reduces fetal transmission risk. If infection is confirmed, pyrimethamine and sulfadiazine may be used after the first trimester.
Immunocompromised individuals: High-risk patients (e.g., HIV/AIDS) need prolonged treatment with pyrimethamine, sulfadiazine, and folinic acid to prevent relapse.

Animals

Cats: Clindamycin (10–12.5 mg/kg orally every 12 hours for 4 weeks) is the primary treatment. Ocular cases may require additional glucocorticoids.
Dogs: Treated similarly to cats, with clindamycin for 3–4 weeks. Supportive care, including anticonvulsants for seizures, may be needed.

Lessons for Rescuers and the Public

This case underscores the importance of understanding behavioural changes in wildlife. Simply looking healthy is not a defence against disease, and assuming a fox is tame rather than ill can lead to dangerous misunderstandings. Habituation and disease-related neurological changes can look very similar, but their implications are vastly different.

Wildlife rescuers and members of the public should remain cautious around abnormally friendly wild foxes and report unusual behaviour to experienced professionals. Testing and responsible decision-making are critical to protecting both individual animals and broader wildlife populations.

Summary

This case highlights the need for increased awareness of toxoplasmosis in wildlife management. The silent spread of the disease among wildlife has significant implications for conservation, animal welfare, and public health. By recognizing the signs and acting responsibly, we can help mitigate these risks and ensure the right decisions are made for both wild and captive foxes alike.

Early recognition, proper testing, and responsible care decisions are essential to protecting both animal populations and human health. Infected foxes pose additional risks to vulnerable individuals, such as pregnant people or those with weakened immune systems. With limited treatment options available, strict hygiene practices, quarantine measures, and, in some cases, humane euthanasia are necessary steps to manage the disease and prevent its spread.

References:

The Fox Forum