- Malaria: description
- Malaria: symptoms
- Malaria: causes and risk factors
- Malaria: examinations and diagnosis
- Malaria: treatment
- Malaria: disease course and prognosis
malaria is a disease that is especially common in the tropics and subtropics. It is triggered by so-called plasmodia (unicellular parasites), which are transmitted through the bite of the Anopheles mosquito. The typical symptoms are fevers, which alternate with fever-free intervals (intermittent fever). Malaria can be treated with medication and then usually has a favorable prognosis, but if left untreated it can be fatal. For prophylaxis also different drugs are used. Read all important information about the disease here.
ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in doctor's letters or on incapacity certificates. B50B51B54B52B53
Causes and risk factors
Examinations and diagnosis
Disease course and prognosis
Malaria (also called malaria or intermittent fever) is an infectious disease caused by plasmodia (single-celled parasites). The term comes from the Italian "mala aria", which means something like "bad air". The reason: In the past, the formation of malaria was attributed to the bad, musty air that is found mainly in wetlands. However, the fact that it actually occurs in warm, humid, swampy areas has another cause: it is transmitted by the Anopheles mosquito, which has excellent living conditions in such areas.
Malaria is considered a tropical disease, as it occurs mostly in tropical and subtropical countries. The reason for this is that both plasmodium and anopheles mosquitoes can only survive in warm temperatures. Meanwhile, however, it is also increasingly occurring in Europe, for example in Greece.
The parasites need two hosts, in which they live in different shapes: the mosquito serves them as the main host and the man as the intermediate host. The disease-causing plasmodia enter the human body through the bite of an infected anopheles mosquito. There, they first multiply in the liver, but then scatter and infest the red blood cells (erythrocytes), in which they multiply again. Eventually, the red blood cells burst. The newly formed pathogens return to the bloodstream, whereupon the body reacts with fever. Since the developmental cycle of the plasmodia in the blood corpuscles usually runs cyclically, the fever episodes occur at regular intervals - a chain reaction.
How long the cycle is in the human body depends on the pathogen (between 24 and 72 hours). Depending on the species, disease progression and therapy differ. The most dangerous form is the malaria tropica.
Malaria is one of the most common infectious diseases. It is endemic in more than 100 countries. Endemic means that it occurs frequently in a certain area. About 40 percent of today's world population live in malaria areas. According to estimates by the World Health Organization (WHO), around 216 million people suffer from malaria every year. In 2010, approximately 655,000 people, half of them children, died of malaria. Curable is malaria, when the therapy starts quickly after the infection.
There are certain risk areas for all types of disease. Affected by the Malaria tropica are mainly African countries south of the Sahara, the Pacific but also Southeast Asia with the Indonesian islands, such as the holiday paradise of Gili Islands and the island of Lombok.
Today malaria is also affecting many holidaymakers due to increasing distance tourism. In Germany alone, the Robert Koch Institute reported a total of 547 cases in 2012, most of which had been infected with malaria tropica.
What is malaria tropica?
The most well-known is the so-called malaria tropica, which is responsible for about 80 percent of all malaria cases worldwide. It is caused by Plasmodium falciparum. In contrast to other plasmodium species, Plasmodium falciparum infects both young and older erythrocytes. Since a large number of erythrocytes are destroyed by the parasites ("unlimited parasitemia"), malaria tropica is the most dangerous form of this disease. It is associated with severe complications such as circulatory collapse, shock or pulmonary edema and, if not treated on time, will kill more than 20 percent of the time. In contrast to the other malaria forms, the fever episodes in the malaria tropica occur very irregularly.
Everything important to the typical signs of malaria read in the article Malaria - Symptoms.
Malaria: causes and risk factors
Malaria is caused by small unicellular organisms called plasmodia. The group of plasmodia consists of about 200 subspecies, which occur worldwide.Of these subspecies, however, only five can trigger malaria in humans. These plasmodium species are widespread in tropical and subtropical areas. Plasmodium falciparum and Plasmodium vivax are the most common malaria pathogens. Plasmodium knowlesi occurs only in Southeast Asia.
- Plasmodium falciparum: trigger of the Malaria tropica
- Plasmodium vivax and Plasmodium ovale: trigger of the Malaria tertiana
- Plasmodium malariae: trigger the Malaria quartana
- Plasmodium knowlesi: trigger one Special form of malariawhich is very difficult
Malaria: transmission routes
Plasmodia are most commonly transmitted through the bite of a plasmodium-infected female mosquito (anopheles mosquito, also known as malaria mosquito). The Anopheles mosquito is exclusively twilight and nocturnal. This means that infection usually occurs through a bite in the evenings or at night. In principle, all mammals can become infected with plasmodia, but transmission from other animals to humans is extremely unlikely.
There is a simple formula for the risk of infection in a particular region. The more mosquitoes in an area carry the pathogen, the more people infect them. If left untreated, this in turn increases the likelihood that a previously unaffected insect will secrete parasites during the bloodsucking process.
In rare cases, malaria pathogens can also occur in areas other than the actual risk areas. For example, what is known is the so-called Airport malariain which anopheles mosquitoes brought in by air traffic endanger the airport staff and travelers at a certain airport.
Transmission of the malaria pathogens is also possible through blood transfusion or laboratory accidents. Due to the strict safety regulations, these cases practically do not occur in Germany. In blood transfusions in malarial areas, however, infection can not be ruled out in this way. In rare cases, transmission from the mother to the unborn child is also possible, especially if the placenta is damaged during pregnancy or childbirth.
Malaria: Malaria areas
Which regions of the world are particularly affected by malaria, read in the article Malaria areas.
Sickle cell anemia & malaria
People with a sickle cell disease have some protection against malaria. Malaria is much less common and much weaker. Sickle cell anemia is a hereditary red blood cell disorder that is widespread in Africa. In the affected people, the shape of the blood cells is changed. This has the advantage that the plasmodia can not attack them at all or at least only to a limited degree.
Malaria: incubation period
Malaria does not break out immediately after you have become infected with the virus through a mosquito bite. The incubation period, ie the time between infection and the appearance of the first symptoms, is dependent on the pathogen in malaria:
- Plasmodium falciparum: seven to 20 days
- Plasmodium vivax and Plasmodium ovale: 12 to 18 days
- Plasmodium malariae: 18 to 50 days
In most cases, the disease breaks even in the country itself. Depending on the duration of the trip, the symptoms may not occur until after returning home. If a fever occurs after traveling in malarial areas, an infection must always be excluded by the doctor. In extreme cases, the disease can break out for up to a year after infection. The reason for this is that mainly Plasmodium vivax and oval permanent forms in the liver (hypnozoites) can form. As long as they are exclusively in the liver, no complaints occur. Only when the hypnozoites leave the liver and attack the red blood cells, the typical malaria symptoms become noticeable.
Is malaria contagious?
Transmission of the malaria parasite directly from person to person is not possible. It is only transmitted through the bite of an infected Anopheles mosquito. The likelihood of catching a mosquito bite is particularly high when many people in a region already have malaria.
Malaria: examinations and diagnosis
If malaria is suspected, your GP or a tropical medicine institute is the right place to go. Especially in the early stages of the disease, malaria is often associated with common symptoms that could easily be thought of as a common flu infection (headache, fever, fatigue) or gastrointestinal disease (nausea, vomiting). That's why it often takes a while for sufferers to see a doctor for the first time and make the correct diagnosis. But that is problematic: If malaria is discovered and treated too late, it can be life-threatening.
If you have been in a malaria risk area in the weeks leading up to the onset of symptoms, you should consult a doctor at the slightest sign of incipient disease (especially fever), Even twelve months after a trip to a malaria risk area, every unexplained feverish illness should be investigated accordingly.Then some forms of malaria break out only very delayed.
At the doctor's visit, the doctor will first raise the medical history (anamnesis). Important first clues provide the doctor with the symptoms you are describing. Possible questions could also be:
- When was the last time you were abroad?
- Where were you and how long were you there?
- Were you stung by mosquitoes in the travel destination?
- Did you take malarial prophylaxis in the travel destination?
- When did you first notice symptoms like malaise or fever?
- Do you have a headache or a body ache?
- Are you often sick or need to vomit?
The slightest suspicion of intermittent fever, a blood test is performed. For this purpose, a drop of blood is applied thinly to a glass plate and this blood smear under the microscope considered ("thick drop"). In the case of infection with plasmodia, these can be detected directly in the red blood cells (erythrocytes).
A malaria also recognize doctors on an altered blood picture. In this case, on the one hand, the number of red blood cells is reduced by the parasitic infestation, on the other hand, the number of white blood cells (leukocytes) is increased. The more red blood cells are affected by plasmodia, the more severe the disease. In addition, when assessing the severity of the disease and the physical condition of the person affected plays a role. Among other things, the doctor assesses blood pressure, body temperature and heart rate.
If no pathogens are detected in a blood smear suspected of intermittent fever despite typical malaria symptoms, the blood test is repeated regularly. This is necessary because in the early phase of malaria possibly too few red blood cells are affected and the detection with the "thick drop" is therefore still too uncertain.
Malaria rapid test
In addition to the blood test, a rapid malaria test is also available for diagnostics. This does not indicate the malaria parasite, but the antibodies produced by the body against the pathogen. However, a malaria rapid test is not one hundred percent reliable, so that even with a negative result can be a disease. The result of a rapid test should therefore necessarily be supplemented by a blood diagnosis.
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This is the best way to protect yourself from mosquitoes!
Not only people are happy about the increased temperatures, they also value mosquitoes. Luckily no one is at the mercy of the bloodsuckers. We have the best tips for you on how to protect yourself from the stings and beat the nasty itch for a bargain.
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Make mosquito homeless
Mosquitoes can reach tiny puddles to reproduce. Remove breeding opportunities from your garden and balcony. This means that there should be no water in the pots, the rain barrel should be covered and the gutter so clean that there is no minipump.
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Lock windows and doors?
You do not have to go that crazy - fly screens in front of windows and doors do it too. So you do not have to give up fresh air on hot nights, and the mosquitoes still stay outside.
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Sleep without troublemakers
If you see the mosquitoes whirling around your head at night, you will not only be bitten the next morning, but you will also have no sleep. The easiest solution for a restful sleep despite the bloodsucker: hang a mosquito net over the bed. In the tropics, the nets are even a must, to protect against malaria and other diseases that are transmitted by mosquitoes.
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Invisible to mosquitoes
If you are outdoors, you should spray with mosquito repellent. This "confuses" the senses of the mosquitoes - they can not locate you properly at close range. The most effective is the drug DEET, but has fallen into disrepute lately. Alternatively, there is also a substance called Icaridin.
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Smoke banners against mosquitoes
Candles with essential oils have virtually no effect against mosquitoes. Incense spirals, so-called coils, on the other hand. However, they should only be burned outdoors.
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Drive out itching with heat
With the sting saliva of the mosquito gets into the skin - this contains coagulation factors, which later trigger the itching. There are devices that cause a small heat shock locally and so exactly these enzymes are harmless. However, this only helps immediately after the sting and only the upper layers of the skin are reached.
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Sting, freshly chilled
To reduce the swelling and possible tension pain, it helps to cool the stitch. These are cold envelopes, cooling pads or ice cubes.
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Ointments and gels for mosquito bites
In the market, there are various creams that inhibit the body's own messenger histamine. This causes the immune system to become less active. The swelling should go back so faster and remove the itching.
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Important: Do not scratch your mosquito bites! This will provide satisfaction in the short term, but in the long run it only aggravates the sting. That's because they heat up the immune response and can also incorporate bacteria into the wound. For the "good" feeling you should rather scratch immediately next to the stitch - allegedly it can outsmart the brain.
The therapy depends on the type of plasmodium and the severity of the disease. Also, the doctor considers whether the patient has taken medication for prophylaxis and whether the pathogen is already resistant to certain drugs. In most cases, those affected are immediately referred to a hospital for suspected intermittent fever. If an institute in the vicinity that specializes in such diseases (tropical medicine institute) is located, then those affected are preferably treated there.
As a rule, the disease is treated medically. Depending on the pathogen, different agents are used. Due to the widespread use of drugs in the past, many pathogens are already resistant to certain drugs. For this reason, in many cases a combination of two or more different active ingredients is used.
Malaria tropica: therapy
Due to the potentially life-threatening side effects, a malaria tropica is always treated in hospital, although the course is less dramatic. In the past, on the other hand, most have been prescribed with chloroquine and sulfadoxine. Due to the widespread use of these active ingredients, many pathogen strains have become resistant today. Therefore, in most cases combined preparations of atovaquone with proguanil or artemether with lumefantrine are administered.
When the nervous system is affected, quinine is used in combination with the antibiotic doxycycline. In complicated cases, for example, when various organs are affected by the infection, quinine can also be administered directly into the vein (intravenously). However, this is only possible in Germany in special centers for tropical medicine. The administration of quinine may cause a variety of side effects. These include severe gastrointestinal problems, severe allergic symptoms, low blood pressure, cardiac arrhythmia, dizziness, or a cardiovascular failure. Since the dose of quinine may be made only by a trained specialist.
Mefloquine is rarely used today because it is often associated with serious neurological and psychiatric complications. The application may be necessary if the pathogens are already resistant to other drugs. In very severe cases, in which the effectiveness of the drug therapy is questionable, a blood transfusion or a blood wash (dialysis) can be performed. In such cases, inpatient stay in the intensive care unit is necessary.
Therapy of malaria tertiana and quartana
For malaria quartana, chloroquine is usually prescribed as it has very little resistance to the pathogen (Plasmodium malariae). Chloroquine can be taken in capsule or tablet form. For the treatment of malaria tertiana the same medicines are used as in the malaria tropica. In addition, however, the active substance is also administered primaquine for a week. This is necessary to kill the permanent forms (hypnozoites) in the liver.
In addition to controlling the pathogens malaria is also treated symptomatically. Anti-fever medicines (acetaminophen, ibuprofen) as well as home remedies such as calf wrap and cold compresses help against the high fever. Also important is a sufficient fluid intake and physical protection.
How to prevent malaria, read in the article Malaria prophylaxis.
Malaria: disease course and prognosis
The course of the disease and the prognosis differed in malaria depending on which form is present and at what stage the disease was detected. at Malaria tertiana and quartan the courses are usually relatively mild, and those affected can usually be completely cured within a short time. Severe courses of complications occur in malaria tertiana and quartana only in about two percent of all cases.
In an early discovered and treated Malaria tropica the prognosis is also good. However, a late-onset disease can cause serious complications. This includes, above all, the penetration of the pathogens into the brain. Then you may experience disturbances of consciousness and seizures, or the patient may fall into a coma. It can remain permanent damage even after recovery. If the illness is treated on time, the mortality is about two percent. In the untreated or late treated patients with this form of malaria it is 20 percent.