Prevalence of the flagellate Giardia duodenalis in mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) farms from Croatia

Abstract

Giardia duodenalis ubikvitarna je intestinalna protozoa koja uzrokuje infekcije ljudi i životinja. Može se prenijeti hranom ili vodom. Cilj ovog rada bio je ispitati njenu prisutnost u uzgajalištima školjkaša u Hrvatskoj. Uzorci probavne žlijezde dagnji i kamenica sakupljenih s trinaest uzgajališnih područja, analizirani su metodom ugniježđene lančane reakcije polimerazom i neposrednim sekvencioniranjem trioza fosfat izomeraza gena. Sva ispitivana uzgajališna područja sadržavala su ciste G. duodenalis te je 6,1 % školjkaša bilo pozitivno. Učestalost je varirala ovisno o vrsti školjke i lokaciji iz koje je uzorak uzet. Ustanovljena je prisutnost četiri genske skupine ovog parazita, a to su A, B, C i E. Najčešća je bila skupina A, odnosno pripadajuća podskupina AI.Giardia duodenalis is ubiquitous intestinal protozoa which infects both humans and animals. It can be transmitted through food or water. The aim of this study was the investigation into its presence in shellfish farms from Croatia. Samples of mussels` and oysters` digestive gland, collected from thirteen different farming areas, were analysed by nested Polymerase Chain Reaction, followed by direct sequencing of triosephosphate isomerase gene. All tested farming areas contained Giardia cysts, and 6,1 % of shellfish were positive. Prevalence varied depending on the type of shellfish and locations from which the samples were taken. Four assemblages of this parasite were identified: A, B, C and E. The most common was assemblage A, or more specifically subassemblage AI