Fig 4 -

(A-C) Multiple erythematous, pruritic, painless plaques on the arms and legs of a two-year-old boy diagnosed with concurrent visceral and cutaneous leishmaniasis after congenital transmission of a member belonging to the Leishmania donovani/infantum complex. The insert shows the details of the skin lesions. (D). Hematoxylin-eosin stained tissue section of a skin lesion showing a lymphohistiocytic inflammatory infiltrate with interspersed plasma cells. The insert demonstrates the lack of morphologically visible pathogens.</p

Fig 2 -

(A) Causative agents of cutaneous leishmaniasis cases according to species. Incidences of (B) Leishmania (L.) major, (C) L. tropica, (D) L. infantum, (E) members of the L. donovani/infantum complex (c.), (F) members belonging to the group L. major/tropica/mexicana, (G) members of the L. braziliensis c. and (H) unidentified L. species from 2000 to 2021. h.h., highly homologous; R2, coefficient of determination.</p

Countries and regions visited by patients with cutaneous leishmaniasis.

Countries and regions visited by patients with cutaneous leishmaniasis.</p

Characteristics of cutaneous leishmaniasis cases.

BackgroundLeishmaniasis is caused by infection with intracellular protozoans of the genus Leishmania. Transmission occurs predominantly by the bite of phlebotomine sandflies, other routes, including congenital transmission, are rare. The disease manifests as either cutaneous, visceral or mucosal/mucocutaneous leishmaniasis. In recent years, changes in the epidemiological pattern have been reported from Europe.Principal findingsA total of 311 new and 29 published leishmaniasis cases occurring between 01/01/2000 and 12/31/2021 in Austria were collected and analyzed. These encompassed 146 cutaneous (CL), 14 visceral (VL), 4 mucosal, and 3 cases with concurrent VL and CL. In addition, asymptomatic infections, comprising 11 unspecified cases with Leishmania DNA detectable only in the blood and 162 cases with anti-Leishmania antibodies were reported. Particularly since 2016, the incidence of leishmaniasis has steadily risen, mainly attributable to increasing numbers of CL and cases with positive serology against Leishmania species, whereas the incidence of VL has slowly decreased. Analysis revealed that a shift in the causative species spectrum had occurred and that a substantial number of CL cases were caused by members of the Leishmania donovani/infantum complex. Simultaneous occurrence of VL and CL was identified in immunocompromised individuals, but also in a not yet reported case of an immunocompetent child after vertical transmission.ConclusionsThe incidence of leishmaniasis has risen in the recent years. The numbers are anticipated to keep rising due to increasing human mobility, including travel and forced migration, growing reservoir host populations as well as expansion and dispersal of vector species caused by climate and habitat changes, urbanization and globalization. Hence, elevated awareness for the disease, including possible transmission in previously non-endemic regions and non-vector transmission modes, support of sandfly surveillance efforts and implementation and establishment of public health interventions in a One Health approach are pivotal in the global efforts to control and reduce leishmaniasis.</div

Destinations visited by Austrian patients with serologically confirmed antibodies to <i>Leishmania</i> species.

Destinations visited by Austrian patients with serologically confirmed antibodies to Leishmania species.</p

Cases of leishmaniasis diagnosed at the Medical University of Vienna, Austria, 2000–2021.

Cases of leishmaniasis diagnosed at the Medical University of Vienna, Austria, 2000–2021.</p

Supporting Dataset for Figures.

BackgroundLeishmaniasis is caused by infection with intracellular protozoans of the genus Leishmania. Transmission occurs predominantly by the bite of phlebotomine sandflies, other routes, including congenital transmission, are rare. The disease manifests as either cutaneous, visceral or mucosal/mucocutaneous leishmaniasis. In recent years, changes in the epidemiological pattern have been reported from Europe.Principal findingsA total of 311 new and 29 published leishmaniasis cases occurring between 01/01/2000 and 12/31/2021 in Austria were collected and analyzed. These encompassed 146 cutaneous (CL), 14 visceral (VL), 4 mucosal, and 3 cases with concurrent VL and CL. In addition, asymptomatic infections, comprising 11 unspecified cases with Leishmania DNA detectable only in the blood and 162 cases with anti-Leishmania antibodies were reported. Particularly since 2016, the incidence of leishmaniasis has steadily risen, mainly attributable to increasing numbers of CL and cases with positive serology against Leishmania species, whereas the incidence of VL has slowly decreased. Analysis revealed that a shift in the causative species spectrum had occurred and that a substantial number of CL cases were caused by members of the Leishmania donovani/infantum complex. Simultaneous occurrence of VL and CL was identified in immunocompromised individuals, but also in a not yet reported case of an immunocompetent child after vertical transmission.ConclusionsThe incidence of leishmaniasis has risen in the recent years. The numbers are anticipated to keep rising due to increasing human mobility, including travel and forced migration, growing reservoir host populations as well as expansion and dispersal of vector species caused by climate and habitat changes, urbanization and globalization. Hence, elevated awareness for the disease, including possible transmission in previously non-endemic regions and non-vector transmission modes, support of sandfly surveillance efforts and implementation and establishment of public health interventions in a One Health approach are pivotal in the global efforts to control and reduce leishmaniasis.</div

Causative species according to the year of diagnosis of patients with cutaneous leishmaniasis.

Causative species according to the year of diagnosis of patients with cutaneous leishmaniasis.</p

Fig 5 -

(A) Number of international holiday and business travel trips of the general Austrian population from 2003 to 2021. (B) Number of applications for international protection and refugee status and for subsidiary protection made in Austria from 2000–2021. (C) Annual average temperatures and average temperatures in summer and winter in Austria from 1961–2021.</p

Fig 1 -

Incidences of (A) all leishmaniasis (B) cutaneous (C) visceral and (D) serologically positive cases diagnosed at the Medical University of Vienna, Austria, from 2000 to 2021.</p