Rabies is a deadly viral disease that is transmitted through the bite or scratch of an infected animal. Once rabies symptoms begin, the disease is nearly always fatal. However, the early symptoms of rabies can be easy to miss and often come and go over the course of several days or weeks before progressing to more severe symptoms.
Early Symptoms
The early symptoms of rabies can last for 2-10 days before more advanced symptoms present. These initial symptoms may come and go rather than getting progressively worse. This intermittent nature often leads people to think an animal bite or scratch was not serious initially. Some common early signs and symptoms of rabies include:
- Tingling, prickling, or itching sensation at the site of the bite
- Fever
- Headache
- Nausea
- Loss of appetite
- Fatigue
- Feeling generally unwell or ill (malaise)
These flu-like symptoms may start within a few days of being bitten or scratched by an infected animal. However, they can take weeks or even months to develop in some cases. Throughout the early stages, a person may start to feel better before the symptoms return or worsen. The intermittent nature makes it easy to associate the symptoms with a cold, flu, or other more common illness.
Later Stage Symptoms
After 2-10 days, the virus spreads to the brain and causes more dangerous symptoms. At this point, more overt signs of rabies appear as the disease progresses rapidly. These later stage symptoms may include:
- Agitation
- Confusion
- Hyperactivity
- Difficulty swallowing
- Excessive saliva
- Hallucinations
- Insomnia
- Partial paralysis
Once the brain is infected, rabies is difficult or impossible to treat. Even with aggressive treatment, survival is rare at this stage. As the disease state worsens, symptoms like paralysis, seizures, vomiting, fever, and inability to swallow also set in. The intermittent nature of the early symptoms transitions into a rapidly deteriorating condition.
Incubation Period
The incubation period is the time from infection to when signs and symptoms first appear. For rabies, this can vary greatly:
- Average: 3-8 weeks
- Range: 2 weeks to 6 years (rare cases)
A long incubation period makes it possible to have rabies symptoms come and go over an extended period before the disease progresses. The initial symptoms may be mild and last a few days at a time with gaps of seeming normalcy in between episodes for months. However, once the virus reaches the brain and central nervous system, rapid deterioration begins.
Treatment Seeking Delays
Because early rabies symptoms are generally mild and intermittent, people often do not seek medical treatment right away. This leads to dangerous delays in receiving vaccines and immunoglobulin that could stop the progression. Seeking prompt medical care is essential after any animal bite or scratch. Do not wait for more severe symptoms to present before getting evaluated.
Key points regarding delays in seeking care include:
- Many people assume early symptoms are unrelated to an animal encounter weeks or months prior.
- Intermittent nature of initial symptoms makes rabies less obvious.
- People often wait until symptoms worsen before seeing a doctor.
- Once brain symptoms start, treatment is far less effective.
- All animal bites and scratches should be evaluated quickly for rabies risk.
Diagnosis Challenges
It can be difficult to diagnose rabies during the early stages when symptoms are coming and go. Some reasons rabies goes undiagnosed initially include:
- Flu-like signs are vague and similar to other illnesses.
- Bite wounds have often healed by the time symptoms start.
- Patients may not recall an animal encounter from weeks or months before.
- Doctors may not consider rabies without more typical symptoms present or knowledge of a bite.
- Lab tests can be inconclusive during early disease stages.
However, doctors should consider rabies in anyone with a fever or neurological symptoms who has had any potential exposure to a rabid animal. A full medical history and physical exam focused on finding possible bite wounds and neurological deficits can aid prompt diagnosis.
Rabies in Animals
Rabies is most often transmitted through the bite of an infected animal. In areas where rabies is common, stray dogs are the source of most human cases. Other wildlife like raccoons, skunks, foxes, and bats also frequently carry rabies in the United States. Cats, cattle, and horses can also contract and spread the virus less often.
Animals can exhibit signs and symptoms that come and go during the early stages as well. These may include:
- Fever
- Seizures
- Behavior changes
- Aggression or restlessness
- Excess salivation
- Difficulty swallowing
- Muscle weakness
- Paralysis
Initially, a rabid animal’s behavior may seem only mildly abnormal. But over time, the symptoms worsen progressively until the animal suffers convulsions, paralysis, and inevitable death once the disease reaches an advanced stage.
Prevention
Rabies prevention centers around avoiding contact with rabid animals, prompt wound treatment, and vaccination:
- Avoid approaching or handling unfamiliar animals, especially wildlife.
- Keep pets up-to-date on rabies immunizations.
- Seek medical care immediately to clean and treat any animal bite wound.
- Determine if rabies post-exposure prophylaxis is recommended after an encounter with a suspect rabid animal.
- Maintain up-to-date rabies vaccinations when traveling to endemic areas.
In most countries, rabies immunization involves receiving a series of vaccine shots over two weeks plus rabies immune globulin after a high-risk exposure. This prevents the virus from infecting the central nervous system if given promptly.
Conclusion
Rabies is a deadly disease once symptoms reach the advanced stages, but initial signs are often non-specific and intermittent. It is important to recognize that rabies symptoms may come and go over the early phase, which can last weeks to months. While the early signs are not severe, prompt medical care is still essential after potential rabies exposures before the disease progresses further. In addition, doctors should remain vigilant for rabies when a patient reports neurological or flu-like illness along with an animal bite history, even months later. With widespread animal vaccination programs, public education, and post-exposure prophylaxis, human rabies deaths are preventable.