Differences in clinical manifestations of imported versus autochthonous leptospirosis in Austria and Germany

Abstract

Leptospirosis, a zoonosis occurring worldwide, has a broad spectrum of clinical manifestations. Recently, various countries observed an increase of severe anicteric cases. In Austria and Germany, growing numbers of imported cases are notified in addition to autochthonous infections. The aim of this study was to assess whether imported and autochthonous cases differ in clinical manifestations and outcome. We retrospectively analyzed 24 imported and 35 autochthonous cases treated in six infectious disease units between 1998 and 2008. To compare disease severity, patients were classified according to established independent risk factors for fatal outcome. Although severe leptospirosis (i.e., presence of > or = 1 independent risk factors for death) occurred in similar proportions of imported (67%) and autochthonous (86%) infections (P = 0.1), imported cases were significantly fewer icteric (13% versus 69%; P < 0.0001). In conclusion, an increasing incidence of severe anicteric imported cases of leptospirosis should be anticipated with rising global travel activities.

Figure 1.

Demographics of patients with imported (N = 24) and autochthonous (N = 35) leptospirosis in Austria and Germany. (A) Distribution of age and sex. (B) Countries in which the diseases were contracted. (C) Seasonal distribution. (D) Mode of transmission. Acc = accidental transmission; acc/res = accidental and residential transmission probable; occ = occupational transmission; occ/res = occupational and residential transmission probable; res = residential transmission; unk = unknown.

Figure 2.

Disease severity (ordered by an increasing number of risk factors) and frequency of symptoms and syndromes associated with leptospirosis among patients with (A) imported and (B) autochthonous infections.

Figure 3.

Relevant laboratory parameters of patients with imported (N = 24) and autochthonous (N = 35) leptospirosis in Austria and Germany. In each panel values on admission are represented by the left pair of boxplots, worst values in the course of the disease by the right pair of boxplots. Statistically significant differences are indicated by an asterix (*) with P values of Mann-Whitney U tests given. Dotted lines indicate reference values of conventional units. K⁺ = potassium; BUN = blood urea nitrogen; CRP = C-reactive protein; ALT = alaninaminotransferase; CK = creatinkinase.

Figure 4.

Total number of independent risk factors for (A) death and (B) frequency of individual risk factors among patients with imported (N = 24) and autochthonous leptospirosis (N = 35) in Austria and Germany. WBC = white blood cell count on admission; ARF = acute renal failure; BUN = blood urea nitrogen, K⁺ = potassium on admission.