A cross-sectional epidemiological study of domestic animals related to human leptospirosis cases in Nicaragua

Leptospirosis is one of the most extended zoonosis worldwide and humans become infected most commonly through contact with the urine of carrier animals, either directly or via contaminated water or soil. The aim in this study was to analyse the epidemiological behaviour of Leptospira spp., from domestic animals around the sites of human leptospirosis cases in Nicaragua, from 2007 through 2013. We report the results of a cross-sectional epidemiological study with a non-probability sampling of blood (n = 3050) and urine (n = 299) from Domestic Animals (DA) around the sites of human leptospirosis cases in Nicaragua. We analysed data obtained through Microscopic Agglutination Test (MAT), in-vitro culture, real time PCR and sequencing of lfb1 locus. Frequencies of 30.31% (95% CI: 28.66–31.95) and 15.38% (95% CI: 11.12–19.64) were obtained from serological test and from in-vitro culture, respectively. Although similar frequencies from serology test (P = 0.05) were found in DA species, in-vitro culture frequencies were significantly higher from bovine, equine and sheep (P < 0.05) in comparison with swine and canine species. Ten serogroups of pathogenic Leptospira spp. were encountered, with the highest presence of Icterohaemorrhagiae serogroup 34.65% (95% CI: 29.35–39.94). We identified 7 samples homologous to L. interrogans species Pyrogenes serovar and 3 samples as L. noguchii Louisiana or Panama serovars by analysis of lfb1 sequences. We were able to establish a temporal and spatial correlation from DA and cumulative incidence of human cases. Therefore an effective epidemiological surveillance should be implemented with a specific control program toward DA in order to reduce human leptospirosis incidence

Evolutionary origin, proximate causal organization and signal value of the whistle-shake-display of male shelducks (Tadorna tadorna)

This paper focusses on the phenomenon of emancipation in the Whistle-shake, an epigamic display of male shelducks. A comparison with other motor patterns and vocalizations indicates, that the Whistle-shake is a combination of the comfort movement Body-shake, with integrated elements of another display: Bill-tipping with trill. Between Whistle-shake and Body-shake almost no differences exist in total duration, duration of the sub-units they have in common, and in the number of shaking elements. Artificial rain experiments revealed that the Whistle-shake is not emancipated from the original causal factor, typically influencing the present occurrence of the Body-shake: All males predominantly produced Whistle-shakes when sprayed with water. In addition social factors influence the occurrence of the Whistle-shake. The percentage of shakes consisting of a Whistle-shake was higher in dominant than in subdominant birds. Furthermore, by confronting territorial pairs in spring with either a whistle-shaking or a body-shaking male or an empty neighbouring cage we found that the whistle-shaking male released more Whistle-shakes in the test-males than the body-shaking male. In contrast the test-females, which predominantly produced Body-shakes, did not show any changes in their shaking behaviour in response to the different shaking stimuli presented. Therefore it seems likely that the Whistle-shake and the Body-shake share causal comfort factors but differ in their sensitivity for social stimuli. Context analyses demonstrate that the Whistle-shake shows a sequential association with aggression in dominant males and with escape behaviour in subdominant males. Therefore, the occurrence of the Whistle-shake is not restricted to a specific balance between the activation of motivational systems for aggression and fear. The dual function of the Whistle-shake (comfort and social function) is discussed