Morphological and molecular characterisation of cardiovascular flukes (Digenea: Spirorchiidae) from marine turtles in Moreton Bay, Queensland.
Date:
Spirorchiid blood flukes are globally important parasites of sea turtles, playing a role in strandings and mortalities. Mixed infections are common and ova are found in most host tissues, causing inflammatory responses ranging from mild to severe. However, ova cannot be morphologically identified to species level, making detection of epidemiological and pathological trends difficult.
Method: A multiplex PCR was developed which used genus specific primers to identify groups of spirorchiids present in turtle tissue samples. Second round singleplex PCRs used fluorescently tagged primers, and were followed by restriction digestion and capillary electrophoresis.
Results: The T-RFLP assay detected spirorchiids in 146/151 tissue samples. It characterised spirorchiids in all tissues where ova were detected histologically, and in 28/32 tissues where no ova were observed. 60% of samples tested were infected by multiple species, with Neospirorchis spp. being most prevalent. Numbers of species were greatest in juvenile turtles and animals in poor condition.
Conclusion: This T-RFLP method was sensitive, specific and efficient in identifying spirorchiid ova in turtle tissues, outperforming traditional methods. This is the first use of T-RFLP in tissues or animals, and has potential to be adapted to address a range of questions regarding parasites of other hosts.