It is the disease that has been driving dogs nuts since time immemorial, turning man’s best friend into his worst nightmare. It’s been around for so long that even Aristotle had something to say about it. Nowadays, rabies is under control in most developed countries, but it’s still not uncommon for both people and animals in Asia and Africa to die because of this disease.
What is Rabies?
Rabies is a viral disease belonging to the Rhabdovirideae family. Wild animals such as foxes, polecats and bats are the more common carriers of this cylindrically shaped virus. The most immediate domesticated animals of concern are dogs and cats but the virus has a large host range and can also infect other domesticated animals such as cows and horses.
The usual route of infection is through puncture wounds caused by bites. The virus is usually found in high concentration in the mucous of infected animals. The virus deposited in the wound is then replicated in muscle cells, and after an incubation period of approximately 3 weeks to 2 months, the virus starts traveling up the nervous system from the site of infection up until it reaches the brain. Progression of the disease can be different for different individuals. After reaching the brain the virus then starts being shed into the saliva of the animal and also starts showning symptoms that are classified in 3 different phases.
The first phase is called the prodromal phase. This usually manifests itself within 2 to 3 days and is characterised by nervousness, fever and a change in character. Friendly dogs might start showning shyness, and aggressive dogs might become friendlier. The animal will also obsessively lick the wound of entry. The prodromal phase will then develop into the furious phase or the paralytic phase.
The furious phase is what gives rabies such a bad reputation. So much so that the name of the disease established itself as an adjective in the English language, often used to describe individuals who resort to extreme measures and violence without justifiable reason. The furious phase lasts for about a week. The dog starts to become more restless and irritable, and as the disease progresses, it starts showning increased sensitivity to auditory and visual stimuli. The tell-tale sign of this phase is also an increased predisposition for vicious behaviour. The dog will eventually become increasingly disoriented, start having seizures and will eventually die.
The other possibility is the paralytic phase. It takes place approximately 3 days after observation of the first clinical signs, and is characterised by paralysis of the head and throat. The paralytic phase can be easily recognised due to a hanging mandible, abnormal vocalization and impaired swallowning leading to increased salivation. The animal can be seen to have breathing difficulties and will eventually die of respiratory failure.
Diagnosis and treatment
Unfortunately both treatment and diagnosis are difficult. There is currently no other diagnostic methods other than taking a post mortem tissue sample from the brain, and therefore more often than not the disease is not recognized until the first clinical signs. Work is being done to hopefully develop new diagnostic methods. Fortunately we live in a time where the vaccine for the Rabies virus is readily available.
Given that dog bites and scratches are responsible for 99% of human cases of Rabies, it is very important that man’s best friend is vaccinated for this virus. Vaccination is even more crucial if your dog is not only a friend, but also a hunting partner or a working dog on a farm. This prevents the virus from being contracted from any wild animals that your dog might come in contact with. Flushing and cleaning the wound, and seeking immediate medical attention also significantly reduces the chances of contracting the disease.
It is extremely rare that dogs survive Rabies once the first clinical signs set in. It is generally advisable that a dog exposed to a rabid animal be put down, but if for any reason this is not desired by the owner, the dog needs to be put under strict quarantine for approximately 6 months.