Echinococcus granulosus (‘pig strain’, G6/7) in Southwestern Lithuania

Abstract

BackgroundCystic echinococcosis (CE) of pigs is widespread andknown since many years in Lithuania [1]. Recently, thenumber of diagnosed cases of human CE began toincrease [2] but only limited information is available onthe main epidemiological aspects of this zoonosis.Material and methodsDuring 2005-2006, post slaughter examination and mor-phological identification of cysts from pigs from smallfamily farms (n=612) and industrial farms (n=73) wasperformed. Dog fecal samples (n=240) were collected in12 villages and microscopically examined by egg flota-tion/sieving (F/Si) [3] and modified McMaster methods[4]). For the genetic identification ofE. granulosus tospecies/strain level, PCR was performed with DNA fromtypical hydatid cysts from pigs (n=2), morphologicallyunidentifiable lesions from pigs (n=3), nonfertile cystsfrom cattle (n=3) and taeniid eggs from dog faecal sam-ples (n=34) [5]. Risk factors for cystic echinococcosiswere evaluated by a questionnaire.ResultsCE was prevalent in 13.2% (81/612) of the pigs reared insmall family farms and 4.1% of those reared in industrialfarms. Molecular analysis of isolated taeniid eggsrevealed in 10.8% of the dogs investigatedTaenia spp.,in 3.8% E. granulosus (G 6/7) and in 0.8% E. multilocu-laris. In addition, three samples from livers of humanand from a cow were confirmed asE. granulosus larvalstagebyPCR.Sequenceanalysisconfirmedthe‘pigstrain’ (G 6/7) in all pig, dog, cattle and human isolatesinvestigated. No significant risk factor for infectionswith E. granulosus or Taenia spp. could be identified.ConclusionThe ‘pig strain’ of E. granulosus is highly prevalent inthe southwestern part of Lithuania, and transmission ismore likely in small family farms indicating a high expo-sure to cestode eggs in rural areas. Therefore controlprograms should be initiated with special reference tosmall family farms.