A relatively high rate of mortality among engorged females of Ornithodoros moubata (Murray, 1877) was observed in our laboratory colony. The general aim of the study was to identify the causative agent responsible for this mortality. The diagnostic tests were performed by Yeast Identification Service (CBS-Delft, Netherlands) and the pathogen was identified as the yeast Candida haemulonii (van Uden et Kolipinski, 1962) Meyer et Yarrovi, 1978. The artificial infection study was performed by intrahaemocoelic inoculation of yeast suspension, resulting in a mortality of 37%. The maximum mortality of ticks infected per os by contaminated blood meal was 13%. Re-isolated yeast cells from haemolymph of dead and paralysed ticks were apparently identical with primary yeast cells, without loosing reproductive abilities. An occasional formation of elongated chains of yeast cells (pseudomycelium) was recorded. The majority of ticks infected in both experiments mentioned above survived and displayed no evident symptoms of the infection. The presence of yeast cells in the haemolymph of surviving ticks was not detected. The in vitro phagocytosis assay performed with FITC-labelled yeast cells showed that about 4% of tick haemocytes were phagocytically active against the pathogenic yeast cells. Thus phagocytosis seems to be a potent defence reaction against spreading and multiplying of the yeast C. haemulonii within the tick haemocoel.
Sazná nemoc kůry je méně známé onemocnění způsobené houbou Cryptostroma corticale (Ascomycota), s ostrůvkovitým výskytem v Evropě. Postihuje zejména javory kleny (Acer pseudoplatanus) a jejich hromadná vymírání byla zaznamenána u stromů oslabených stresem, především po nadprůměrně suchých a horkých letních měsících. Nedávný výskyt onemocnění v České republice podnítil studium druhu C. corticale a jeho rozšíření v Praze. Výsledek naší čtyřleté studie prokázal, že napadena je minimálně čtvrtina klenů v pražských parcích., Sooty bark disease is a less known disease caused by fungal species Cryptostroma corticale (Ascomycota), with patchy incidence in Europe. It mainly affects Sycamore (Acer pseudoplatanus), and its mass dieback was observed in trees weakened by stress, especially after the exceptionally dry and hot summer months. Recent record of the disease in the Czech Republic prompted the research of C. corticale and its occurrence in Prague. The results of our four-year study showed that at least 25 % of Sycamore trees in Prague parks are infected., and Ivana Kelnarová, Ondřej Koukol, Karel Černý.