Mortality caused by experimental infection with the yeast Candida haemulonii in the adults of Ornithodoros moubata (Acarina: Argasidae).

Abstract:

: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.

journal_title

Folia parasitologica

authors

Loosová G,Jindrák L,Kopácek P

keywords:

subject

Has Abstract

pub_date

2001-01-01 00:00:00

pages

149-53

issue

2

eissn

0015-5683

issn

1803-6465

journal_volume

48

pub_type

杂志文章