Leishmaniasis
Visceral leishmaniasis is a tropical disease, and if untreated it is often fatal. There are a number of varieties of Leishmania that can cause disease in humans, affecting different organs: skin, mucous membranes and visceral reticuloendothelial organs. Cutaneous leishmaniasis is cosmetically disfiguring, but not fatal, while mucocutaneous leishmaniasis can lead to lethal secondary infections. Visceral leishmaniasis is due either to Leishmania donovani (East Africa and India) or Leishmania infantum (Europe, North Africa and South America). The transmission of the parasite takes place either zoonotically, i.e., by means of an animal as intermediate host, or anthroponotically, i.e., from human via insect vector to human. Dogs are the main hosts in Europe, but other animals, including rodents, can also be intermediate hosts. After transmission from the insect vector, the parasite is absorbed by macrophages where it is transformed from promastigote to amastigote, reproduces and spreads to the entire reticuloendothelial system. The infection can also be asymptomatic, but in the event of impaired immunity, for example due to concurrent HIV infection, the probability of a severe course increases (13) – (15).
The incubation period is normally 2 – 6 months, but may be several years (13). The disease often follows an insidious course, with gradual onset of lethargy, fever, weight loss and hepatosplenomegaly. Anaemia develops as a result of bone marrow failure, haemolysis and hypersplenism. Later, liver failure takes place, with jaundice and ascites. Liver failure and thrombocytopaenia may also cause bleeding diathesis. The name kala-azar (black fever) refers to a darkening of the skin which is one of the clinical symptoms on the Indian sub-continent.
Visceral leishmaniasis causes some 50 000 deaths annually, worldwide (16). The disease is most prevalent in Latin America, Africa and southern parts of Asia, but the occurrence is also increasing in southern Europe. The increase is associated with increased travel activity, more people with an impaired immune system and a growing catchment area for host animals and vectors. There is an abundance of sandflies today in the deciduous forests of northern Spain and central France, although no correlation has been found with climate changes (4). In northern Europe, the disease is most relevant for people who have been to Mediterranean or more remote regions in the course of the past year, and have symptoms.
There are few described cases of haemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis. Since the two conditions have overlapping clinical features, it is easy to overlook visceral leishmaniasis as the causal factor, particularly in our part of the world, where this disease virtually does not occur. Both haemophagocytic lymphohistiocytosis and visceral leishmaniasis may be difficult to detect in bone marrow smears in an early phase of the disease. Visceral leishmaniasis must be considered and excluded in patients with haemophagocytic lymphohistiocytosis before immuneosuppressive treatment is started. In the event of clinical suspicion of visceral leishmaniasis, bone marrow examinations must be repeated, and spleen and bone marrow aspirate cultured. Serological tests may be diagnostic even when bone marrow findings are negative (12, 17). Our patient had a positive direct antiglobulin test and autoantibodies against thrombocytes and granulocytes. This confused us, but has been described previously in connection with leishmania-associated haemophagocytic lymphohistiocytosis. It is assumed that the finding is due to polyclonal activation of B-lymphocytes due to a concurrent high IgG level (12). In our patient a direct antiglobulin test was negative six weeks after start of treatment, while the antibodies against granulocytes and thrombocytes were not checked later. Liposomal amphotericin B is the first choice of treatment for visceral leishmaniasis. Our patient was also given dexamethasone for a day and a half, but no other treatment for haemophagocytic lymphohistiocytosis. After a year of observation, she is still free of symptoms.
This case report describes a prolonged and atypical febrile illness. The GP treated the patient for recurrent airway infections, and at first we suspected acute leukaemia. The diagnosis haemophagocytic lymphohistiocytosis is well known in large paediatric departments, and was made early. Haemophagocytic lymphohistiocytosis secondary to visceral leishmaniasis is very rare in Norway, however.
The girl’s mother mentioned the insect bite already on admission, but no weight was attached to it in the first assessment. Later she again commented on the bite, which helped to put us on the track of the correct diagnosis. The case report underscores the importance of a thorough anamnesis, which must be seen in context with the clinical symptoms and the clinical findings. A complete travel history is necessary in connection with febrile diseases after time spent in tropical and subtropical areas, including the Mediterranean area (Box 2).
Box 2
Things to remember about your trip
Local conditions (standard of living, drinking water, day trips)
Other fellow travellers who are/were sick
Close contact with insects or other animals (bites, stings, bathing)
Geographical conditions (detailed description of travel itinerary)
Vaccination status (basic vaccinations, relevant vaccinations, malaria prophylaxis)
Epidemics and known outbreaks of tropical diseases in the area
Infections during travel
Illness after return home