Summary about Disease
Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The rabies virus infects the central nervous system, ultimately causing disease in the brain and death. It is almost always fatal once symptoms develop.
Symptoms
Early symptoms of rabies are similar to many other illnesses, including fever, headache, and general weakness or discomfort. As the disease progresses, more specific signs appear and may include:
Insomnia
Anxiety
Confusion
Agitation
Partial or slight paralysis
Excitation
Hallucinations
Excessive salivation
Difficulty swallowing
Fear of water (hydrophobia)
Causes
Rabies is caused by the rabies virus, usually transmitted through the saliva of an infected animal. This commonly occurs via a bite or, less frequently, when infectious material from a rabid animal (saliva or brain tissue) gets into an open wound or mucous membranes, such as the eyes, nose, or mouth. Common carriers are wild animals like raccoons, bats, skunks, and foxes. Domestic animals, such as dogs and cats, can also transmit rabies if they are not vaccinated.
Medicine Used
There is no specific treatment once rabies symptoms appear. Medical care is mainly supportive. The focus is on comfort and minimizing suffering. However, if a person is bitten by an animal suspected of having rabies, they should seek immediate medical attention for post-exposure prophylaxis (PEP). PEP involves a series of rabies vaccine injections and, in some cases, rabies immunoglobulin (HRIG). HRIG provides immediate, passive immunity until the body can produce its own antibodies through vaccination.
Is Communicable
Rabies is communicable from animals to humans, and rarely, from humans to humans. Animal-to-human transmission typically occurs through bites. Human-to-human transmission is extremely rare but has been documented in cases of corneal transplants where the donor was unknowingly infected with rabies.
Precautions
Vaccinate pets against rabies.
Keep pets under supervision to prevent contact with wild animals.
Avoid contact with wild animals, especially those that appear sick or act strangely.
Report any animal bites to local authorities.
If bitten by an animal, wash the wound thoroughly with soap and water for at least 15 minutes and seek immediate medical attention.
Educate children about the dangers of approaching or handling unfamiliar animals.
How long does an outbreak last?
The duration of a rabies outbreak in a specific area can vary significantly depending on factors such as the reservoir species involved, the effectiveness of vaccination programs, and control measures implemented. Outbreaks can last for several months to years if not effectively managed. In individual animals, the incubation period (time between exposure and symptom onset) can range from weeks to months, and once symptoms develop, death typically occurs within days.
How is it diagnosed?
Rabies is difficult to diagnose in humans before the onset of symptoms. After symptoms appear, diagnosis is typically made through a combination of factors, including:
History of animal bite or exposure
Clinical signs and symptoms
Laboratory tests on saliva, skin biopsies (nerves at the nape of the neck), spinal fluid, or serum. These tests look for the presence of the virus or rabies antibodies.
Post-mortem examination of brain tissue In animals, diagnosis is usually made post-mortem through a test called the fluorescent antibody test (FAT) on brain tissue.
Timeline of Symptoms
The incubation period for rabies can vary widely, ranging from weeks to months (typically 3-12 weeks, but sometimes longer). Factors influencing the incubation period include the location of the bite, the severity of the wound, and the amount of virus introduced.
Incubation Period: Asymptomatic. The virus travels from the site of entry to the central nervous system.
Prodromal Stage (2-10 days): Flu-like symptoms, such as fever, headache, malaise, fatigue, and itching or discomfort at the site of the bite.
Acute Neurologic Phase (2-7 days): This phase manifests in one of two forms:
Furious Rabies: Characterized by hyperactivity, agitation, hydrophobia (fear of water), aerophobia (fear of drafts or fresh air), confusion, hallucinations, and seizures.
Paralytic Rabies: Characterized by ascending paralysis, beginning at the site of the bite, leading to coma and eventually death.
Coma and Death: Both forms of rabies ultimately progress to coma and death, typically within days of the onset of neurologic symptoms.
Important Considerations
Post-exposure prophylaxis (PEP) is highly effective if administered promptly after exposure. Delays in seeking treatment significantly increase the risk of developing rabies.
Rabies is almost always fatal once symptoms develop.
Prevention through vaccination of domestic animals and avoiding contact with wild animals is crucial.
Prompt reporting of animal bites to public health authorities is essential for timely investigation and administration of PEP when necessary.
Bats are a significant source of rabies transmission, and even a seemingly minor bat bite should be evaluated by a medical professional.