Why do dogs die after being bitten by a rabid animal? - briefly
Dogs may die after being bitten by a rabid animal due to the rapid progression of the rabies virus within their system. Once symptoms appear, the disease is almost always fatal.
Why do dogs die after being bitten by a rabid animal? - in detail
Dogs may die after being bitten by a rabid animal due to the severe and often fatal nature of the rabies virus infection. Rabies is a zoonotic disease caused by viruses in the Lyssavirus genus, with the most common being Rabies lyssavirus. The virus primarily affects the nervous system, leading to progressive neurological signs and eventual death.
Upon infection, the rabies virus replicates in muscle tissue near the bite site before spreading to the peripheral nerves and traveling along nerve axons towards the brain. This journey can take anywhere from a few days to several months, depending on the distance between the bite site and the central nervous system (CNS). During this time, the dog may not show any clinical signs of infection, a period known as the incubation phase.
Once the virus reaches the CNS, it begins to replicate in neurons, causing inflammation and damage to brain tissue. The most common initial symptoms are changes in behavior, such as increased aggression or restlessness. As the disease progresses, affected dogs may exhibit a range of neurological signs, including:
- Paralysis, particularly of the throat and jaw muscles (dysphagia)
- Excessive drooling (ptyalism)
- Hydrophobia (fear of water)
- Ataxia (loss of balance and coordination)
- Seizures
- Abnormal behavior, such as biting at imaginary objects or exhibiting unusual aggression
The progression from the onset of clinical signs to death is typically rapid, often within days. This swift deterioration is due to the rabies virus's ability to evade the immune system and replicate unchecked in neurons. Once clinical signs appear, the prognosis for infected dogs is grim, with mortality rates approaching 100%.
It is crucial to note that rabies is a reportable disease, meaning that cases must be reported to local health authorities. This is because rabies can also infect humans, with similar fatal consequences if left untreated. In areas where rabies is endemic, vaccination of dogs and other susceptible animals is essential for controlling the spread of the virus and protecting both human and animal populations.
In summary, dogs die after being bitten by a rabid animal due to the severe and often fatal nature of the rabies virus infection. The virus's ability to spread undetected through nerves to the brain, causing progressive neurological damage and evading the immune system, leads to a rapid and usually fatal outcome. Vaccination and prompt reporting of suspected cases are vital for controlling the spread of rabies and protecting both human and animal health.