Rabies in humans: Unmasking rabies: A silent killer among humans

The virus of rabies has been infamously known for spreading the disease among humans and animals. The viral disease affects individuals who have been bitten by an infected animal. With tens of thousands of deaths occurring each year, it has become one of the most concerned public health issues worldwide.

The viral disease is known to affect the central nervous system as it belongs to the Rhabdoviridae family and is primarily transmitted through the saliva of infected animals. The virus travels from the site of the bite to the brain, where it causes inflammation and, ultimately, death if left untreated.

Signs of rabies in humans

Dogs can transmit the disease (Image via Getty Images)

The symptoms vary depending on the stage of the infection, so here are all the notable ones everyone should be aware of:

Flu-like symptoms: In the early stages, individuals may experience non-specific flu-like symptoms, such as fever, headache, fatigue, and general malaise which are often mistaken for other illnesses, making early diagnosis challenging.
Anxiety and agitation: As the disease progresses, individuals may become increasingly anxious, restless, and irritable showing signs of anxiety while also experiencing difficulty sleeping and having abnormal sensations at the bite site.
Hydrophobia: One of the hallmark symptoms of rabies is hydrophobia, which is a fear of water. People with the disease experience extreme discomfort or panic when attempting to drink water or even when hearing or seeing water.
Excessive salivation: Another common symptom is excessive salivation or frothing at the mouth which occurs due to the effect of the virus on the salivary glands.
Difficulty swallowing: Rabies can cause spasms in the throat muscles, leading to difficulty in swallowing which is known as dysphagia, and can result in severe pain and discomfort when trying to eat or drink.
Muscle weakness and paralysis: As the virus progresses through the nervous system, it can cause muscle weakness, loss of coordination, and paralysis which generally begins in the extremities and gradually spreads towards the trunk.
Hallucinations and delirium: Advanced stages of rabies may induce neurological symptoms like hallucinations, confusion, delirium, and bizarre behaviors which reflect the severe impact of the virus on the brain.

Know about the modes of transmission

Rabies is typically transmitted through the bite or scratch of an infected carrier like dogs, bats, raccoons, foxes, and skunks. It also has a good possibility of being transmitted if infected saliva comes into contact with mucous membranes or open wounds.

Dogs and other animals can transmit the disease (Image via Getty Images)

While any mammal can contract the disease, certain animals are more commonly associated with the transmission of the virus, like dogs are known to be the primary source of rabies cases in many parts of the world, particularly in regions where canine vaccination programs are inadequate. Bats are another known carrier of the virus which poses a risk to both humans and other animals.

Diagnosis of rabies in humans

Diagnosing rabies in humans can be challenging due to the absence of specific clinical features in the early stages and the rapid progression of the disease so, doctors, generally combine these factors as an approach to the diagnosis:

Patient history: Gathering a detailed history includes information about animal bites or scratches, contact with potentially infected animals, or travel to regions known for cases of the disease.

Clinical symptoms: The clinical presentation of symptoms are hydrophobia, excessive salivation, muscle spasms, and neurological abnormalities that are highly suggestive of the disease.

Laboratory tests: The following tests can aid in diagnosis:

Reverse Transcription Polymerase Chain Reaction (RT-PCR): This test detects the presence of the viral RNA in saliva, cerebrospinal fluid (CSF), or skin biopsies which can be used to confirm the diagnosis during the early stages of the disease or in cases where a patient's history suggests exposure to rabies.
Immunofluorescence Assay: Immunofluorescence tests detect viral antigens in skin biopsy samples or neural tissue that helps to visualize the presence of the rabies virus and are commonly used in postmortem examinations.
Serological tests: Serological tests measure the presence of rabies-specific antibodies in the blood which are useful for determining a person's immune response to the virus and can be conducted during the later stages of the disease or after potential exposure.

Treatment of rabies in humans

There is no known cure for this particular disease, but immediate medical attention and specific treatments would help prevent the onset of symptoms and the progression of the disease. This preventive treatment is known as post-exposure prophylaxis (PEP) and consists of two key components:

Wound care: If a person is bitten or scratched by an animal suspected of having the virus, then the wound should be washed thoroughly with soap and water for at least 15 minutes. This action helps remove the virus from the site of the bite or scratch and may reduce the risk of infection.
Vaccination: The mainstay of PEP is the administration of a series of vaccinations which in general involves receiving a series of injections of vaccine over a specific timeframe. The vaccine helps stimulate the immune system to produce antibodies against the virus, providing protection against the disease.

Dogs can transmit the virus (Image via Getty Images)

In addition to the vaccine, if the risk of virus exposure is considered high, a rabies immunoglobulin (RIG) may also be administered which contains preformed antibodies and provides immediate, temporary immunity against the virus while the vaccine stimulates the body's immune response.