Visceral leishmaniasis (Kala Azar) is an infectious disease due to a parasitic pathogen (Leishmania) common in tropical and subtropical areas. Depending on the pathogen subtype, visceral leishmaniasis can have a severe course.
What is visceral leishmaniasis?
Visceral leishmaniasis (kala azar) is the name given to an infectious disease rarely encountered in Germany that is due to transmission of the parasitic infectious agent (Leishmania) by insects (butterfly midges, sand flies). The pathogens of visceral leishmaniasis belong to the class of protozoa (animal protozoa), the so-called Mastigophora (also: flagellates), which are widespread in Asia (especially India), Africa, South America and the Mediterranean region. In most cases, affected persons become infected with the pathogen during their travels to these countries. While other forms of leishmaniasis affect the skin (cutaneous leishmaniasis) or skin and mucous membrane (mucocutaneous leishmaniasis), the most severe form of infection with Leishmania, visceral leishmaniasis, affects the internal organs, especially the spleen, liver, lymph nodes and bone marrow. In addition, skin changes may occur in the form of dark patches, from which the Indian term for visceral leishmaniasis, kala azar (“black skin”), is derived.
Causes
Visceral leishmaniasis is caused by a parasitic pathogen (Leishmania donovani, L. chagasi, L. infantum) that belongs to the class Mastigophora. Infection with visceral leishmaniasis occurs via bites of certain insect species (sand flies) that have previously infected vertebrates (mouse, wolf, dog). After the insect bite, the leishmania invade the monocyte-macrophage system, which is involved in immune regulation in cooperation with lymphocytes and eliminates degradation and foreign substances, and multiply. The monocyte-macrophage system includes reticular connective tissue in lymphoid organs, Kupffer stellate cells in the liver, and histiocytes in the skin. Accordingly, these organ systems are severely affected. In addition to indirect infection through insect bites, direct transmission is possible through organ transplantation as well as blood donations.
Symptoms, complaints, and signs
The symptoms of visceral leishmaniasis (kala azar) depend on the type of pathogen and how strong the immune system of the infected person is. There are infections that run without symptoms, but usually the bone marrow, liver, spleen or lymph nodes are affected by the disease. The disease can either start gradually or break out suddenly, in which case patients suffer from a very strong feeling of illness. Typical symptoms include swelling of the lymph nodes, weight loss, diarrhea and abdominal pain. Often, the spleen and liver are also swollen, which can be recognized by a distended abdomen. Furthermore, changes in the blood count also occur. For example, those affected suffer from blood coagulation disorders or anemia. Skin changes are also common, with dark red papules or brown-black spots. As the disease progresses, the skin then turns grayish. For this reason, visceral leishmaniasis is also called kala azar (“black skin”). After one to three years, the affected person can develop a so-called post-Kala Azar skin leishmaniasis. Reddish or light-colored spots then appear on the body or face, which then become nodules or papules and whose appearance is also reminiscent of leprosy.
Diagnosis and course
Visceral leishmaniasis manifests after an incubation period of 10 days to 10 months (occasionally longer) on the basis of characteristic symptoms such as gradual or sudden onset of disease with remittent fever lasting for weeks, abdominal pain, Hepatosplenomegaly (enlargement of the liver and spleen), swelling of the lymph nodes, marked hypochromic anemia (hemoglobin deficiency), thrombocytopenia (platelet deficiency), and dark, patchy skin pigmentation, amyloidosis (protein deposits), and cachexia (emaciation). Visceral leishmaniasis is confirmed by pathogen detection in bone, spleen, liver, or lymph node punctate.In the advanced stage of the disease, puncture is no longer possible in some cases of visceral leishmaniasis, so that the diagnosis is confirmed using serological tests (immunofluorescence method, ELISA technique). A leishmanin reaction test can be performed to determine the immune status of the affected individual. The course of visceral leishmaniasis depends to a large extent on the pathogen subtype. Whereas Leishmania chagasi and Leishmania infantum often cause no symptoms and heal on their own, Leishmania donovani infections, which are protracted in many cases, can be lethal if left untreated.
Complications
In Kala Azar, affected individuals suffer from various skin lesions. These have a very negative effect on the aesthetics of the affected person and in the process can also lead to inferiority complexes or significantly lowered self-esteem in the patient. In children, the disease can thus also trigger bullying or teasing. Furthermore, Kala Azar leads to the formation of ulcers and further to a severe weight loss of the patient. Those affected sometimes suffer from diarrhea and vomiting and may also experience severe pain in the abdominal area. Furthermore, the lymph nodes of the affected person also swell and fever occurs. Patients appear fatigued and tired and can no longer perform strenuous activities. As a rule, the disease has a negative impact on the life and daily routine of the affected person. In most cases, Kala Azar can be treated relatively well with the help of medication. No particular complications occur and the symptoms are significantly alleviated. In some cases, however, the medication can lead to side effects. If treatment is successful, the patient’s life expectancy is not reduced.
When should you see a doctor?
If health disorders develop during a stay in Africa, South America as well as the area around the Mediterranean Sea, a doctor should be consulted. If the changes in health occur after a visit to the region there, the affected person also needs a clarification of the complaints. Basically, however, it is important to inform oneself about the health conditions on site immediately before starting a trip. It must be clarified which diseases are to be expected and by which means transmission can take place. If necessary, vaccinations are recommended. If swelling of the lymph glands, changes in the appearance of the skin or unwanted weight loss are noticed after an insect bite, action is required. In case of diarrhea, abdominal pain, nausea and a general feeling of illness, consultation with a physician is recommended. The cause must be clarified and a diagnosis made. This is the only way to develop a treatment plan that can help alleviate the symptoms as quickly as possible. To avoid complications and minimize risks, consultation with a physician is necessary if malaise occurs, lumps form on the skin or discoloration is observed. Internal weakness, circulatory disturbances and an increased need for sleep are further signs of a present disease. Because organic changes may occur in visceral leishmaniasis, immediate action should be taken at the first signs.
Treatment and therapy
Visceral leishmaniasis is treated systemically with Ambisome (liposomal amphotericin B). Liposomal amphotericin B is well tolerated in most cases and is infused intravenously as part of a 10- to 20-day course of therapy. In cases of intolerance or nonresponse to liposomal amphotericin therapy, miltefosine and pentavalent antimony preparations are used as alternatives for visceral leishmaniasis. Miltefosine is administered orally in tablet form twice daily for one month and causes only minor gastrointestinal discomfort (episodic diarrhea or vomiting). In contrast, pentavalent antimonials (sodium stibogluconate, meglumine antimonate) are injected intramuscularly or intravenously by a physician as part of an average 28-day course of therapy in a hospital setting; prolonged dull pain at the injection site, nausea, and headache may be side effects. In some cases, therapy with antimonene is ineffective for visceral leishmaniasis because the infectious agents have developed resistance to this agent.Pentamidine and the antibiotic paromycin are also used as antiprotozoal agents against visceral leishmaniasis. Pentamidine, however, leads to pronounced side effects and, among other things, impairs glucose metabolism disorders (diabetes mellitus) in more than 10 percent of those affected.
Prevention
Because visceral leishmaniasis is transmitted to humans via insects, appropriate precautions should be taken to protect against mosquito bites when traveling to areas such as Asia, primarily India, Africa, the Mediterranean region, and South America. These include wearing suitable, long-sleeved clothing and the use of a close-meshed mosquito net while sleeping. To date, no protective vaccination against visceral leishmaniasis exists.
Follow-up
Because visceral leishmaniasis affects the internal organs, its successful treatment should always be followed by intensive aftercare. Central to this is the early recognition and timely treatment of secondary diseases of the organs. Accordingly, even after a successfully treated visceral leishmaniasis, regular measurements of organ values in the blood should be performed. In particular, the organs that were affected by visceral leishmaniasis should also be regularly examined with imaging techniques (MRI, CT, X-ray, ultrasound), so that hidden organ damage that is not yet visible in the blood can also be detected. If the skin was also affected by visceral leishmaniasis, the corresponding areas must be regularly examined by a dermatologist, and tissue samples should be examined for the pathogen to be sure. In addition, persons formerly suffering from visceral leishmaniasis should avoid traveling to areas (Asia) where the disease-carrying sandfly lives. If such travel cannot be avoided, intensive mosquito protection as well as skin hygiene should be observed to avoid a recurrence of visceral leishmaniasis. Mosquito nets should be very close-meshed (1.2 millimeters), as the sand fly is very small. In addition, mosquito repellent sprays such as Autan (so-called repellents) should be sprayed several times a day. In addition, daily showers should be taken. Face, neck and hands must also be covered with cloth if possible.
What you can do yourself
Drug therapy for visceral leishmaniasis can be supported by patients’ own initiative. First, it is important to watch for typical side effects such as kidney pain or hypersensitivity disorders. If pain or other symptoms occur, the physician must be informed. After intravenous treatment, bed rest is recommended in order to quickly cure side effects such as headache and pain in the limbs. The cause of visceral leishmaniasis must be determined to prevent re-infection. Kala-azar is usually transmitted by insects. Therefore, proper insect repellent must be used during future travel. Affected individuals should wear appropriate clothing and sleep with a fly net at night. People who have already contracted kala-azar once are not allowed to participate in blood donation. This safety precaution serves to prevent transmission of the pathogen to other people. The ban on blood donation must be strictly adhered to, otherwise there is a risk of severe penalties. Finally, after an illness, attention should be paid to unusual symptoms. In individual cases, the pathogen returns months or even years later and causes serious health problems. Comprehensive prophylaxis in the form of regular checkups is therefore absolutely necessary.