bệnh dại

Cúm là gì?

rabies là an acute viral encephalomyelitis (inflammatory disease of the brain and/or spinal cord) caused by infection with the rabies virus, a type of lyssavirus. Other lyssaviruses include Australian bat lyssavirus (ABLV) and the European bat lyssavirus (EBLV).

Rabies is transmitted to humans via bites or scratches from animals infected with the virus. Infection with các rabies virus, and other lyssaviruses, resultS in Một progressive inflammation of the brain and spinal cord. Without vaccination Và effective post-exposure management, rabies là almost always fatal. 

Cần để ý những gì

The incubation period of rabies is generally between 3 and 12 weeks, but the onset of symptoms has occurred as early as days after exposure or as long as 19 years later.   

Early signs of infection involve non-specific symptoms, such as loss of appetite, cough, fever, headache, discomfort and fatigue, nausea and vomiting, and sore throat. There also may be discomfort, paraesthesia (prickling or itching sensation) and fasciculations (muscle twitching) at the site of the scratch or bite.  A person may show signs of anxiety, confusion and agitation. These initial symptoms last 1 to 4 days. Following this, symptoms progress to: 

• delirium and bizarre behaviour 
• disorientation
• hallucinations 
• hypersalivation, hyperthermia and hyperventilation (signs of autonomic instability) 
• hydrophobia (fear of water) 
• paralysis 
• insomnia.

The disease progresses rapidly. Once clinical signs have developed, the person’s neurological status will deteriorate over a period of up to 12 days, resulting in death. There is no specific treatment for rabies.

Bệnh lây truyền qua đường nào

Rabies is a zoonotic disease (spread between animals and humans). Dog species (including wolves, coyotes, foxes and jackals) are the main source of infection for humans. Skunks, raccoons, monkeys and bats can also harbour infection.  

Human exposure occurs primarily through the scratch or deep bite of an infected animal. Transmission can also occur if saliva of an infected animal comes into direct contact with a person’s mucosal surface (nose, eyes or mouth).  

The virus travels from the site of the injury to the brain by moving along nerve pathways.

Dịch tễ học

Rabies is found in animals on all continents of the globe except Antarctica. Australia is currently rabies free. However, ABLV has been known to occur in fruit bats and insectivorous bats.  It is difficult to determine the disease burden in animals, due to the impracticalities of testing wild and domestic animals. 

Each year, rabies infection causes approximately 59,000 human deaths worldwide, 95% of these occurring in Africa and Asia. The burden of disease in humans is higher in rural, low-income populations. Children are more likely to be infected due to their size and proximity to the ground, being less likely to appreciate an animal’s temperament, and their tendency to make sudden movements or loud noises which are intimidating to animals. 

Phòng ngừa

According to the World Health Organization, vaccinating dogs in rabies-prone regions is the most cost-effective strategy for preventing rabies in people.

People who will be travelling to, or living in, rabies-prone regions should take preventative measures. These include:

• avoiding close contact with wild and domestic animals (this is especially important for children)
• not feeding, patting or playing with animals
• getting vaccinated.

Vaccination

Vaccines can be administered either before potential exposure (pre-exposure prophylaxis), or after exposure has occurred (as part of post-exposure prophylaxis). 

Pre-exposure vaccination requires fewer vaccine doses and eliminates the need for immunoglobulin if exposed (except for those who are severely immunocompromised). Immunoglobulin may be expensive and difficult to source in developing countries.  

There are 2 rabies vaccines available in Australia: 

• Verorab 
• Rabipur 

Both Verorab and Rabipur are inactivated vaccines and can be administered via the intramuscular (IM) route or the intradermal (ID) route.  

It is preferable but not essential to use the same brand of vaccine for the entire course. If using the same brand is not possible, vaccination should not be delayed, and the alternate brand should be used. 

Boosters and serology 

Recommendations for vaccine boosters and serology (blood testing to check antibody levels) vary on a case-by-case basis. Individuals should seek personalised advice from their healthcare provider (e.g. immunisation provider, travel medicine adviser or other specialist consultant). 

It is especially important for individuals in the following groups to speak with their health provider for specific advice on boosters and serology: 

• immunocompromised individuals 
• laboratory workers who work with live lyssaviruses 
• people with ongoing exposure to bats or potentially rabid mammals. 

Table 2: Immunisation Handbook Serology recommendations

* Or, receive a booster dose every 3 years without checking serology.

A single IM booster dose is recommended for people with significant ongoing exposure risk: 

• when serology is < 0.5 IU/mL   
• 12 months after dose 1 of primary course of vaccination (whether pre- or post-exposure) then every 3 years after first booster (may check serology first).

Các biện pháp phòng ngừa

People with anaphylaxis to egg should receive Verorab instead of Rabipur. 

People with latex allergy should receive Rabipur instead of Verorab.  

Phối hợp với các loại vắc-xin khác

Verorab and Rabipur can be co-administered with other vaccines, using separate injection sites.  

Tetanus vaccination status should also be considered after a bite or scratch from an animal, see MVEC: Tetanus. 

Tác dụng phụ của vắc-xin

Common side effects following rabies vaccination include nausea, headache, injection site pain and myalgia (muscle aches). 

Due to the seriousness of disease, post exposure vaccination should never be delayed, even in those who have experienced an unpleasant side effect or who have a history of allergic reactions. A specialist immunisation service should be contacted for specific advice. 

Tài liệu

• Australian Immunisation Handbook guideline 
• RCH post-exposure Clinical Practice Guideline
• Overseas post-exposure prophylaxis guidelines
• Ordering vaccines online 
• DOH notification requirements