The term “brain parasite” is used to describe any of a number of different parasitic creatures that can affect the central nervous system, including the brain and spinal cord. Cats are susceptible to several different types of parasites that can potentially make their way into the brain and related tissues. Symptoms can range from non-existent to severe and may be fatal in some cases. Parasites in the brain often cause encephalitis or brain inflammation, which causes the majority of symptoms. Cats suffering from a brain parasite may experience behavior changes and issues with muscle control. Parasites are more likely in cats that are allowed outdoors, eat food they catch or raw meat, have immune disorders, or live in cramped conditions with other animals.

Symptoms of brain parasites can vary, and some cats with parasite activity in the brain and related tissues will never present any symptoms. Most symptoms relate to activity controlled by the central nervous system including muscle control, behavior, and occasionally hearing or vision issues. The cat may also exhibit signs related to parasite infestation in other parts of the body. Parasites in the lungs, gastrointestinal system and urinary tract may have localized as well as neurological symptoms. 

Symptoms Include:

Various types of parasites can make their way into the brain and related tissues. Parasites that can be found in the central nervous system include:

Brain parasites enter your cat’s system much the same way as any parasite. The most common cause is ingestion, usually through a food source like raw meat or wildlife. Risk factors include spending time outdoors, living in cramped quarters with other animals, and unmonitored eating habits. Once inside your pet, the parasite takes full advantage of its host, growing to maturity and laying its own eggs, which further the infestation. When the adult parasites, larvae, or eggs find their way through the bloodstream or nasal passages into the central nervous system, they can cause damage to the brain and other related systems. In some cases, the eggs form cysts that put pressure on brain, eye, and ear structures causing symptoms.

A veterinarian can diagnose brain parasites by confirming the presence of the parasite, its larvae, or its eggs in your pet’s system if clinical signs point to the condition. Other diseases and disorders can cause similar symptoms, so your veterinarian may need to conduct several tests to rule out other potential issues. Be prepared to discuss your cat’s history, eating habits, and all symptoms you have observed. A physical examination will be followed up with a blood, urine, and fecal analysis. In many cases, spinal fluid will also be obtained and analyzed. Your veterinarian may use additional methods to check for parasites, including imaging technology and contrast dyes.

The treatment plan for your pet will vary based on the type of parasite and severity of the symptoms. Many pets will not require any treatment, as some brain parasites have short life cycles and will not continue to cause harm to your cat. If treatment is required, your veterinarian may choose one or more of the following treatment methods:

Many cats with a brain parasite will make a full recovery. Continue to follow the directions of your veterinarian, providing the full course of prescribed medications and returning for follow-up visits as needed. Seek assistance immediately if symptoms appear to worsen or don’t get better after several days. It is also a good idea to thoroughly clean your cat’s living area, including all food and water dishes and their litter box. Scoop the litter box daily and wash your hands.

In severe cases, your pet may lose some of its abilities. Vision or hearing loss caused by the brain parasite may be permanent. Even if your cat experiences loss of vision or hearing, they can still lead a full life. Provide your pet additional support and time as they adjust to their new ability level and learn to compensate with their other senses.