A problem that occurs during or after a trip does not necessarily need to have a causal connection with that trip. It should be determined whether it is an acute or a chronic problem, if the spleen is enlarged and whether or not there is fever. Try to make a distinction between a (infectious) disease which results in leukopaenia and leukopaenia which results in infection.

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Infectious diseases that are frequently accompanied by leukopenia include:

• typhoid fever (Salmonella typhi)
• typhus or spotted fever (rickettsiosis)
• arboviroses
• brucellosis
• visceral leishmaniasis
• miliary tuberculosis

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Malaria is a common illness, but only occasionally causes leukopenia. Leukopenia in kala azar and malaria are associated with hypersplenism, which can give rise to leukopenia, thrombocytopenia, anaemia or pancytopenia. Leukopenia will in rare cases also be encountered in AIDS and tuberculosis.

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Other differential diagnosis:

• Bone marrow suppression (e.g. due to medication, agranulocytosis with thyreostatics, chloramphenicol, or amodiaquine) or bone marrow infiltration can likewise cause leukopenia.
• Certain autoimmune diseases, e.g. Felty syndrome, may likewise be accompanied by leukopenia.
• Felty syndrome is characterised by the triad of seropositive rheumatoid arthritis, splenomegaly and granulocytopenia.