Rabies

Rabies is an infectious disease, which usually takes a fatal course and is mainly transmitted from mammals to humans. The rabies pathogen is the lyssavirus.

Worldwide, the number of rabies deaths is about 55,000 per year, although the number of unreported cases is probably much higher.

The majority of European countries are now "rabies-free". The last official rabies case in Germany was discovered in a fox in 2006, while in 2007 rabies was last diagnosed in a man infected by a dog bite during a stay in Morocco.

Rabies is caused by the lyssavirus, which is mainly found in forest animals in industrialised countries. These can further transmit the virus to domestic animals and humans. In Africa, Asia and South America, on the other hand, the rabies pathogen is mainly passed on by dogs, which are thus responsible for most rabies deaths worldwide.

Rabies is transmitted through the bite of dogs, cats, foxes, raccoons, skunks, jackals and wolves, which are themselves infected with rabies. Insectivores such as hedgehogs and vampire bats are also possible vectors. Less common, however, is transmission by herbivores, such as horses, small game, and cattle, which can themselves become infected but are not carriers themselves.

The incubation period is usually three to eight weeks. In rare cases, the infection can go unnoticed for several years until it breaks out. However, no noticeable symptoms are to be expected before nine days. If the site where the virus has entered the body is close to the brain, a very short incubation period can be expected, since the virus strives to find its way to the brain along the nerves. Once there, the final outbreak of the disease occurs.

In the case of simple contact, such as petting, with a rabies-infected animal, the risk of infection is quite low, since the virus is transmitted mainly through saliva. The viruses prefer to enter the body through mucous membranes or wounds. Therefore, most people become infected through bites or scratches.

Three stages can be distinguished in the rabies disease.

For the first stage (prodromal stage), non-specific symptoms such as fever, headache, nausea, vomiting, abdominal pain, diarrhea and possibly cough are typical. Later, there may also be an increase in irritability to light, sound, and drafts. The fever rises steadily.

In the further course it comes to the acute stage (excitation stage). Here symptoms such as hyperactivity with muscle twitching and convulsions occur. There is an increased feeling of anxiety, restlessness, aggressiveness, interrupted by depressive phases and hydrophobia. The visual or acoustic perception of water alone can lead to restlessness and convulsions, which can extend to the entire musculature.

The third and final stage (paralysis stage) is characterized by progressive paralysis. The affected person becomes comatose and eventually dies from respiratory paralysis. Rabies never takes a positive course and always ends fatally in the event of an outbreak.

Rabies can be diagnosed by the typical clinical symptoms, as well as after a detailed questioning of the history (anamnesis) of the complaints.

To confirm the suspicion of rabies, the genetic material (RNA) of the rabies pathogen is detected in saliva, in the cornea of the eye and in the cerebrospinal fluid (CSF). In many cases, it is not even possible to diagnose rabies with certainty in this way. A definite diagnosis is often only possible after the death of the patient.

To prevent rabies infection, it is best to give prophylaxis. Vaccination offers the highest protection against rabies. Should an animal bite occur, it is important to clean the wound thoroughly and rinse with clean water. Soap or dishwashing solutions can also be effective. Afterwards, the wound can be disinfected with alcohol or iodine solution. However, these methods do not replace a visit to the doctor, which is essential in this situation.

According to the WHO, a rabies vaccination is even advisable if only minor scratches have occurred or an animal has gnawed on the skin. The vaccination contains both ready-made antibodies (passive immunization) and killed virus components (active immunization).

At the appearance of the first rabies symptoms, the vaccination or administration of antiserum is already ineffective. The aim of further therapy is merely to alleviate the symptoms. After the first appearance of symptoms, death usually occurs within the next seven days.

Without medical countermeasures, the majority of people bitten by rabid animals contract rabies.

The mortality rate is 100% once the symptoms have appeared, since paralysis of the respiratory and cardiac muscles lead to death within a few days.

If rabies infection is suspected, active and passive vaccine can be administered retrospectively. If this is done within a prescribed time window, rabies can almost be ruled out.

For people who have regular contact with animals, such as veterinarians or foresters, rabies vaccination is definitely advisable or even essential. Tourists travelling to areas where the risk of rabies is increased should also be vaccinated against rabies.

To prevent rabies, contact with apparently trusting animals such as dogs and cats should generally be avoided. In the tropics and subtropics, caution should be exercised with any animal, and especially street dogs, as they are considered suspected of being rabid. In case of scratch or bite wounds, the doctor should be consulted immediately, who should administer the preventive rabies vaccination in any case before returning from vacation. Therefore, before traveling to a rabies-prone country, the vaccination should be scheduled in time.