03302naa a2200553 a 450000100080000000500110000800800410001902400380006010000200009824501240011826000090024252017910025165000300204265000170207265000240208965000140211365000210212765000210214865000140216965000130218365000200219665000190221665000170223565000160225265000200226865000130228865000250230165000110232665000130233765000140235065000250236465000240238965000220241365000130243565000200244865000180246865000160248665000150250265000160251765000140253365300140254765300200256165300170258165300210259865300150261965300250263470000190265977300700267815202542019-09-26       1980    bl uuuu     u00u1 u    #d7 a10.1016/0022-2011(80)90180-92DOI1 aCOSTA, C. A. F.  aHyperparasitism of intrasnail stages of Fasciola hepatica by a mosquito microsporidian parasite.h[electronic resource]  c1980  aAbstract: Microsporidia are being developed as biological control agents for pests and parasites; their host specificity has been considered a taxonomic indicator. For these reasons the infection pattern following ingestion of Nosema algerae microsporidia was studied in the snail (Lymnaea cubensis) infected with Fasciola hepatica. The experimental group (A) comprised 30 snails exposed to F. hepatica miracidia 21 days prior to exposure to N. algerae spores. Group B (20 snails) were exposed to N. algerae spores without exposure to the trematode miracidia. Group C (70 snails) were exposed to trematode miracidia but not to the microsporidian. Group D (50 snails) were exposed to neither infective agent. Of these groups only 8 snails in group A were found to harbour microsporidia-infected F. hepatica larvae when inspected (by tissue smear and Giemsa staining) 22 days after exposure to N. algerae. Of these 8, 5 had microsporidia in their tissues. The proportion of snails with microsporidia-infected F. hepatica larvae was 0 at 5 days after exposure to the microsporidian, 14% at day 15 and 63% at day 22. It is concluded that the microsporidia are transmitted to F. hepatica by host ingestion. This is the first case to be described of such transmission to F. hepatica of a microsporidian arthropod pathogen. The presence in snail tissues of microsporidia may be due to contamination during removal of the infected trematode larvae. It can be inferred that microsporidia must reside for a time in snail tissues since theydo not appear in F. hepatica until 15 days after exposure. In demonstrating the possibility of hyperparasitic infection of trematodos by arthropod microsporidia, the study raises doubts as to the value of host type in microsporidian taxonomy. M. J. Whitaker  aBiological control agents  afascioliasis  aFreshwater molluscs  aHelminths  ahost specificity  aMicrosporidiosis  amiracidia  aMollusca  aNatural enemies  aNosema algerae  aParasitology  aParasitoses  aPlatyhelminthes  aProtozoa  aProtozoal infections  aSnails  aTaxonomy  aTrematoda  aTrematode infections  aControle biológico  aFasciola hepatica  aHelminto  aInimigo natural  aParasitologia  aPlatelminto  aProtozoose  aTrematódeo  aVerminose  aEukaryota  aGiemsa staining  aHelminthoses  aLymnaea cubensis  aMicrospora  aSnail-borne diseases1 aBRADLEY, R. E.  tJournal of Invertebrate Pathologygv. 35, n. 2, p. 175-181, 1980.