Complete sequences of ribosomal and mitochondrial genes of the giant liver fluke Fascioloides magna are presented. In particular, small subunit (18S) and internal transcribed spacers (ITS1 and ITS2) of the ribosomal gene (rDNA), as well as cytochrome c oxidase subunit I ( cox 1) and nicotinamide dehydrogenase subunit I ( nad 1) of the mitochondrial DNA (mtDNA), were analyzed. The 18S and ITS sequences were compared with previously published sequences of the liver fluke Fasciola hepatica . Fixed interspecific genetic differences were determined that allow molecular differentiation of F. magna and F. hepatica using either the PCR-RFLP method or PCR amplification of species-specific DNA regions. Additionally, intraspecific sequence polymorphism of the complete cox 1 and nad 1 mitochondrial genes in geographically distinct F. magna populations was determined. Based on the sequence divergences, short (<500 bp) variable regions suitable for broader biogeographical studies of giant liver fluke were designed.

Whether the brown rat ( Rattus norvegicus ) is a reservoir of Trichinella spp. infection or merely an accidental host, which may be vector of Trichinella spp., continues to be debated. We estimated the prevalence of Trichinella sp. infection in brown rat populations and in domestic pigs in 2 villages in Croatia, where Trichinella sp. infection in pigs has been endemic in the past 10 yr. Trichinella spiralis larvae, identified by a multiplex polymerase chain reaction analyses, were the only species detected in both rats and pigs. In 2001 and 2002, 2,287 rats were collected on 60 farms with different levels of sanitation and with, or without, T. spiralis –infected pigs. The prevalence of infection in rats ranged from 0.2 to 10.7%. Infected rats were detected only on farms with T. spiralis –positive pigs and low sanitation or formerly with low sanitation ( P = 0.007, Fisher's exact test), yet no infected rat was detected on farms with T. spiralis –negative pigs. The finding that no infected rat was found on farms with T. spiralis –negative pigs suggests that, in the investigated area, the brown rat is not a reservoir but only a victim of improper pig slaughtering.