Toxoplasmosis in the Red Fox (Vulpes vulpes)
These oocysts often occur in parts of the brain. Studies in rats have shown that rats infected with Toxoplasmosis do not fear cat pheromones even though Rodents instinctively shy away from the smells of a cat. So it would seem that for the parasite to complete its life cycle the infected rat would have to be caught by a cat. What better way than to infect the part of the brain that would normally shy away from this and make life harder for the cat to catch the rat! So the cat catches and kills the rat and eats it and the life cycle is complete and ready to start again when the cat goes toilet.
But what happens if it is a fox that catches the rat. It would seem that the Toxoplasmosis goes through the same stages and infects the part of the brain that is usually associated with fear and the fight or flight instinct. Whilst the fox can't pass on this disease, it is left with the condition none the less. However some foxes in good health and with a good immune system can fight this successfully.
Symptoms we have noticed in Toxo positive foxes are as follows: No fear and no real signs of aggression, circling, head pressing, food dangling from the foxes mouth whilst the fox seems completely unaware of this. Walking up to an object and then just standing there, seemingly unaware of the fact that if it moved to the left or right it could pass the object in the way. Following feet but unaware of things going on above knee level, teeth grinding and in extreme cases fitting. With all the Toxo infected foxes we have dealt with over the years however none were suitable for release back to the wild as the condition left them almost like a domestic dog.