Neospora caninum is a parasite belonging to the subclass coccidia (Coccidiasina) and it is used by horses, cattle and other mammals as hosts. They cause a contagious disease, known as neosporosis in dogs. Dogs are the only permanent hosts, so the pathogen usually establishes itself in their muscle tissues in the form of tissue cysts.
In general, many of the infected dogs are asymptomatic, but especially puppies can have a very poor prognosis. Read more about neosporosis in dogs and how to make a correct diagnosis.
What does Neospora caninum mean in dogs?
As we mentioned earlier, the cause of this infection is Neospora caninum , which is an intracellular parasite. Until recently, researchers believed that dogs were the only definitive host, but studies revealed that other canines, such as coyotes, gray wolves and dingo, may also be ultimate hosts.
Veterinary websites estimate that the prevalence of the parasite – the number of infected dogs in a given population – varies from 0 to 100%, depending on the region. In Sweden, a study from 1994 indicates that the prevalence is as low as 0.5% in the dog population, while estimates from the USA indicate that about 7% of all dogs in certain areas there test positive. In England, the prevalence is between 5.5-23.6%.
The parasite has three forms depending on the stages of the life cycle. They are as follows:
- Oocysts: An analogue to eggs that are formed in the dog’s intestinal tract and excreted in the feces.
- Tachyzoites: The infectious forms that spread from oocysts when they enter a dog.
- Bradyzoites: Which create cysts in the animal’s muscles.
Symptoms of Neospora caninum in dogs
As we have said, many infected dogs never show any symptoms. Unfortunately, some adult dogs and especially puppies will be more likely to develop severe clinical signs. These signs are the result of tachyzoites that cause inflammation and necrosis in affected tissues.
Because of this, the most common symptoms are neuromuscular. Among them we find the following:
- The typical symptoms of the infection occur in puppies under 6 months. These can cause paralysis of the hind legs, which follows an upward pattern. This clinical sign usually begins to appear at 3-9 weeks of age.
- Widespread muscle atrophy, which also occurs in an upward pattern. The hind legs are usually more affected than the front legs in the beginning.
- Difficulty selling, paralysis of the jaws and marked cervical weakness may follow.
- Other complications include pneumonia, seizures, anorexia, weakness, myocarditis and, in the worst case, death.
- In puppies that are symptomatic, muscle atrophy is progressive and results in continuous contraction of the affected muscles. When this clinical picture emerges, the prognosis is very poor.
We must remember that so far there is no 100% effective treatment. Some types of antibiotics that can be administered to puppies have been shown to be successful, but medication does not guarantee the animal’s survival. Clindamycin is the drug that is recommended from 3 weeks of age and up to 2 months in almost all cases.
In general, adult dogs tend to respond better to treatment than puppies. However, when neuromuscular clinical symptoms occur in the animal, the prognosis will be extremely poor.
If the treatment is started quickly and administered before paralysis begins, the prognosis improves slightly.
Prevention of Neospora caninum in dogs
Since there is no definitive treatment, the best course of action is to prevent the disease. Veterinary websites inform us that pregnant dogs can transmit the pathogen to their puppies via the placenta, so we must be very careful with pregnant bitches.
In general, dogs get the disease by maintaining close contact with meat or cattle whose tissues have bradyzoites. Veterinarians still do not know if the oocysts in the environment are also contagious to dogs – even if they are for livestock. For this reason, the best way to limit contact with livestock is as much as possible.
As you may have noticed, Neospora caninum in dogs often goes unnoticed, but when it begins to manifest, it can be fatal. If there are signs of the disease in your region, limit the dog’s contact with livestock and the rural environment. In infectious diseases, it is always better to prevent than to cure.
This article might interest you…