Leishmaniasis: diagnostic issues in Europe

Abstract

Leishmaniasis is a parasitic disease with clinical presentations that vary from asymptomatic infection to cutaneous, mucocutaneous or visceral disease. Recent epidemiological studies have shown an increased prevalence in Europe largely caused by an increase in international travel, difficulty eradicating leishmanial infection in AIDS patients, and the use of immunosuppressive medications. Clinical diagnosis may be challenging, and parasitological diagnosis entails the use of invasive procedures which may be unrevealing in the immunosuppressed. A number of less invasive tests for the detection of anti-leishmanial antibodies or leishmanial antigen are available but their sensitivity and specificity may vary with the infective species and results have to be interpreted in light of the clinical presentation. The availability of polymerase chain reaction assays amplifying leishmanial genetic material has been a major step forward in improving the diagnosis of leishmanial disease and the response to treatment.

Keywords:

• anti-leishmanial antibodies
• cutaneous leishmaniasis
• Europe
• leishmania PCR
• parasitological diagnosis
• visceral leishmaniasis

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Key issues

• Leishmaniasis, presenting as visceral, cutaneous or mucocutaneous forms, is an important parasitic infection that may be fatal or disfiguring if left untreated.

• Recent epidemiological studies have demonstrated an emergence of leishmanial disease across Europe due to increasing international travel and a higher prevalence of HIV and other immunosuppressive states.

• Treatment of leishmaniasis may be prolonged and may be associated with toxic side effects, so that accurate and efficient diagnosis is essential.

• Identification of leishmanial amastigotes is considered the gold standard diagnostic method, but obtaining clinical specimens for this purpose is invasive.

• Antibody detection through ELISA, IFAT, ICT and DAT methods are used widely, but the usefulness of such techniques is limited in immunosuppressed patients whose antibody responses are poor.

• Antigen detection is a more recent approach to leishmanial diagnosis, with urine assays found to be promising for point-of-care use.

• Molecular techniques using PCR allow accurate species identification as well as assessment of response to treatment and parasite load, though standardization of the primers, reagents and protocols is needed.