Chikungunya

Florian Tiefenböck studied human medicine at the LMU Munich. In March 2014, he joined as a student and has supported the editorial team with medical articles ever since. After receiving his medical license and practical work in internal medicine at the University Hospital Augsburg, he has been a permanent member of the team since December 2019 and, among other things, ensures the medical quality of the tools.

More posts by Florian Tiefenböck All content is checked by medical journalists.

Chikungunya is a febrile viral disease. It occurs mainly in Africa and Southeast Asia and is transmitted by mosquitoes. In addition to a high fever, severe muscle and joint pain are typical Chikungunya symptoms. Usually the disease heals without consequences. However, only the symptoms can be treated, not the virus that caused it. Read everything you need to know about Chikungunya here.

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. A92

Chikungunya: description

Chikungunya is a febrile infectious disease. It is caused by the Chikungunya virus. This pathogen, also known as the CHIK virus, is transmitted to humans by mosquitoes. The name comes from Tanzania. In the Makonde language, Chikungunya means "to bend" or "to become curved", which indicates the typical Chikungunya symptoms, namely joint and muscle pain.

Chikungunya occurs in many Asian and African countries, including the tropical regions of the Indian subcontinent and the Pacific islands. In 2013, Chikungunya hit Caribbean islands, spreading for the first time in the North, Central and South America region. Previously, there were only isolated cases of returnees there.

In the course of global warming, the mosquito that transmits the virus is also appearing in Europe. So far, transmissions from Italy (almost 200 sick people in 2007 from a vacationer who returned from southern India) and France have been detected. Chikungunya is one of the "travel diseases" due to its prevalence.

In 2014, according to the Robert Koch Institute, Chikungunya fever was observed in 162 vacationers. In the previous year there were only 16. The reason for the increase is believed to be the spread of the Chikungunya virus in American countries. The number of Asian tiger mosquitoes - as typical carriers of the CHIK virus - is also increasing in Germany. However, there has not yet been any disease transmission.

Chikungunya: symptoms

The first symptoms of Chikungunya disease appear after about two to seven, sometimes even after twelve days (incubation period). Infected people suddenly develop a high fever (an average of 39 degrees Celsius) and headaches. In some cases, the increased body temperature drops abruptly after a few days, but quickly rises again shortly after (about one to three days, sometimes even after a week). In this case, doctors speak of a biphasic fever. The rapid rise in temperature can cause infants and young children to experience febrile seizures.

Typical Chikungunya symptoms are severe joint and muscle pain (arthralgia and myalgia) that appear from the beginning. These are sometimes so unbearable that those affected can hardly stand. In some cases, sufferers also complain of swollen joints and lymph nodes. Conjunctivitis, sore throat, and abdominal pain are rare but possible symptoms of chikungunya. The hot, well-perfused skin (flush) can sometimes be followed by an itchy, lumpy, blotchy rash (maculopapular rash). Chikungunya's severe feeling of illness, accompanied by exhaustion and nausea, subsides after about one to two weeks.

The chikungunya symptoms are sometimes very strong. However, not everyone who is infected will develop signs of the disease. In some cases, chikungunya is also symptom-free. In about a quarter of those affected, the disease progresses more severely with punctiform skin hemorrhages (petechiae) and mucosal hemorrhages (e.g. nosebleeds). In this case, doctors speak of a hemorrhagic Chikungunya fever, which is why Chikungunya is also counted among the hemorrhagic fever diseases.

Chikungunya: causes and risk factors

Two points play a crucial role in the causes of Chikungunya disease. On the one hand the Chikungunya virus itself as a pathogen, on the other hand its transmission to humans.

Chikungunya virus

The CHIK virus belongs to the family of the so-called Togaviridae and to the large genus of the alphaviruses. Chikungunya is an RNA virus and was first described in an outbreak in Tanzania in 1952/53. It is similar to the O'nyong-Nyong virus. Other typical Togaviruses are, for example, the Ross River virus, the Eastern and Western encephalitis virus or the rubella virus. The viruses spread via the lymph nodes and the blood How exactly the virus infects human cells is still being investigated. Once it has penetrated there, the pathogen uses the cell components to multiply. The Chikungunya virus is divided into three variants based on the smallest structural differences, a West African, an East-Central virus. South African and one Asian, so it should be able to adapt to new geographical circumstances.

Transmission of the Chikungunya virus

The CHIK virus is transmitted from person to person almost exclusively by mosquitoes. Classic representatives are mosquitoes of the genus Aedes aegypti, Aedes albopictus, Aedes africanus, Aedes furcifer and Mansonia species. But mosquitoes of the Culex genus are also possible transmitters. The virus spreads and multiplies in the human body after being bitten. If it bites again, the mosquito will pick up the Chikungunya virus and pass it on to other people.

This cycle has also been observed in monkeys, baboons and rodents (jungle cycle). However, the animals are only intermediate carriers of the virus, which is ultimately transmitted from the animals to humans through mosquito bites (bridge transmission). Particular attention should be paid to the mosquito species Aedes albopictus. Known as the Asian tiger mosquito, it is currently spreading around the world and is responsible for transmission in Italy, among other things. In Germany, too, their eggs were discovered in 2007, and finally living specimens in 2011.

This small (5mm), black-silver-white striped mosquito is very active. In addition, it not only transmits Chikungunya, but also West Nile, yellow fever and dengue viruses. In India and Southeast Asia in particular, chikungunya has therefore been observed at the same time as dengue fever. Other mosquito species can also cause several diseases - for example Aedes aegypti the yellow fever.

risk groups

People with high blood pressure, diabetes, or heart failure, the elderly over 65 years of age, and newborns are at increased risk of the chikungunya virus causing severe disease. Pregnancies are an equally dangerous risk factor as mothers can pass the virus on to their child.

Chikungunya: diagnosis and examination

If you suspect that you have Chikungunya, you should consult your family doctor or a specialist in tropical medicine. Since there are no clear early symptoms, the taking of the medical history (anamnesis) is of crucial importance. The doctor first asks about typical symptoms (and their course). Information on recent trips is particularly important. You may be asked the following questions:

• How long have the complaints existed?
• When was the last time you were abroad?
• Where did you go How long was your stay in the travel destination?
• Have you been bitten by mosquitos?
• Do you have fever? Or have you recently measured elevated body temperatures?
• Have your symptoms subsided in the meantime and are now increasing again (as an indication of the possible biphasic chikungunya course)?
• Do you have (unbearable) joint pain or swelling?

After taking the medical history, your doctor will perform a physical examination. Among other things, he can measure your body temperature and palpate your lymph nodes. He will pay particular attention to the joints and assess possible swelling or reddening of the skin.

Laboratory tests

There are several laboratory procedures that can be used to confirm a diagnosis of chikungunya. To do this, the doctor takes several blood samples. Nonspecific blood values ​​can be changed and generally indicate a physical illness. These include, for example, a reduction in white (lymphopenia) and red blood cells (anemia) and platelets (thrombocytopenia). In severe cases, liver values ​​can also be increased, for example.

For reliable detection, the Chikungunya virus can either be isolated directly or its genetic material can be detected. In addition, infected blood is tested for specific antibodies against chikungunya. The virus itself can be grown in certain cultures within the first three days. Specific proteins of the human immune system, so-called immunogobulin (Ig) M antibodies, usually appear five to seven days after the onset of the disease and remain detectable for up to six months. IgG antibodies can be determined from about the second week and months afterwards. The so-called polymerase chain reaction (PCR) can reproduce parts of the virus genome (virus RNA) and confirm Chikungunya fever.

Dengue fever and other illnesses

When examining Chikungunya, the doctor will also rule out other diseases, especially other tropical diseases. These include leptospirosis, malaria, diseases caused by other alphaviruses (e.g. O "nyong-nyong, Ross river), rubella, enterovirus and parvovirus infections, but also rheumatic diseases such as post-infectious arthritis. Due to similar symptoms, but a more severe course of the disease , dengue fever must be taken into account. The following table compares chikungunya with dengue fever:

symptom	Chikungunya	Dengue
fever	suddenly	Gradually increasing
Duration of fever	usually only a few days	one week
blotchy, lumpy rash	frequently	Rare
Bleeding (haemorrhagic fever)	Rare	almost always
Joint pain	almost always and long-lasting (sometimes months)	rarely and if so, of significantly shorter duration

In addition, the laboratory values ​​usually differ. While the white blood cells are usually reduced in Chikungunya, their number rarely changes in Dengue. The opposite is true for blood platelets. They are significantly reduced, especially in dengue fever. If you have symptoms of illness such as fever, headache and body aches, nausea and vomiting, during or after a trip, especially in risk areas, you should therefore consult a doctor immediately.

Chikungunya: treatment

There is no treatment that directly fights and clears the Chikungunya virus from the body. Therefore, only the symptoms of the disease can be treated and alleviated. Bed rest and adequate fluid intake are crucial, as the body loses a lot of water, especially during a fever. Medicines for pain (analgesics) and fever (antipyretics) alleviate typical chikungunya symptoms. Non-steroidal anti-inflammatory drugs (anti-inflammatory drugs, NSAIDs) are particularly suitable for this.

In the case of persistent joint pain, painkillers (locally applied) corticosteroids and physiotherapy can have beneficial effects. In high-risk areas of dengue fever, acetaminophen (paracetamol) is usually always used to reduce the risk of bleeding. Acetylsalicylic acid (ASA), which disrupts the function of the blood platelets, should therefore be avoided. If the Chikungunya fever is severe, intensive medical monitoring may be necessary. The treatment is also extended accordingly for other symptoms such as conjunctivitis.

Chikungunya vaccination

A vaccine with inactivated Chikungunya virus particles is currently being tested. However, preventive medication is not yet possible.

Chikungunya: disease course and prognosis

The Chikungunya virus can present itself in different ways. In some cases it doesn't cause any symptoms. If chikungunya fever occurs, it usually heals within a few weeks without any consequences. However, the joint problems can sometimes persist for months and occur in different joints. The virus can also affect the liver or nervous system, especially in young children. These severe courses of the disease are very rare, but represent a life-threatening situation. On average, about 4 out of 100 sufferers die of Chikungunya. Young children are at slightly higher risk of dying from chikungunya.

Preventing chikungunya

Chikungunya virus cannot be treated or vaccinated against it. Therefore, some measures should be followed to protect against mosquito bites that transmit the virus. You should also avoid mosquitoes in the first week in the event of illness, as the virus is reabsorbed and passed on to other people if the bites take place again.

Use insect repellent!

These so-called repellents with the active ingredients DEET, Icaridin, IR3535 or plant-based lemon eucalyptus oil or products based on it, namely PMD / Citriodiol, are particularly effective.

Wear long pants and long-sleeved clothing!

For extra protection, you can wash or spray your clothes with permethrin.

Watch out for mosquito nets, especially over the bed and on the windows!

This is especially true during sleep phases during the day, as the Chikungunya mosquitoes bite particularly aggressively at this time.

Avoid and eliminate water spots in your area!

Mosquitoes that transmit chikungunya multiply here. You should therefore empty your buckets and buckets regularly or cover places where new mosquitoes can develop in the moisture. Avoid living in the immediate vicinity of ponds or similar water points. The use of insecticides may be necessary.

Do not travel to risk areas if you have health problems or are pregnant!

Further information on high-risk travel areas can be found on the websites of the World Health Organization, the Federal Foreign Office and the European or American health authorities (ECDC, CDC)

In general, you should consult a doctor immediately if you have general symptoms (fever, nausea, vomiting, headache and body aches), especially when traveling to or after traveling to risk areas. Do not be afraid of going to clinics in your country of travel if necessary (- due to the regionally frequent occurrence of Chikungunya experienced -). In this way, a serious course of the disease can be prevented in good time and the spread of chikungunya can be contained.

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