Interactions between anomalous excretory and tegumental epithelia in aberrant Mesocestoides tetrathyridia from Apodemus sylvaticus in Spain

Abstract

Tetrathyridia of Mesocestoides sp. (Platyhelminthes: Cestoda) were collected from the body cavities of Apodemus sylvaticus (Rodentia: Muridae) in Murcia, Spain, and processed by routine microscopical and histological techniques, including examination with brightfield, phase-contrast, and differential-interference-contrast optics. All specimens examined had solid hindbodies (i.e., lacked a primary lacuna), thus conforming to the plerocercoid metacestode type. The vast majority of tetrathyridia were highly aberrant, often lacking a scolex, varying greatly in body size, and exhibiting buds or duplexed body forms indicative of asexual proliferation. All of the aberrant forms, including those with normal scoleces and apparent absence of proliferation, possessed anomalous multi-lobed invaginations of the hindbody tegument, which were attached at many points to abnormally dilated excretory ducts. The tegumental and excretory epithelia were joined basally, but did not share a common lumen. These abnormal connections between these aberrant tegumental modifications and the abnormally dilated excretory ducts have not been described previously for any metacestode. This report contributes to understanding previously published reports of abnormalities in other plerocercoid metacestodes, including Mesocestoides spp. and diphyllobothriidean spargana.

Occurrence of Mesocestoides canislagopodis (Rudolphi, 1810) (Krabbe, 1865) in mammals and birds in Iceland and its molecular discrimination within the Mesocestoides species complex

“…Furthermore, the commonly occurring long-tailed field mouse Apodemus sylvaticus, an important prey species of the arctic fox in Iceland (Hersteinsson 1993), is also suspected to harbor tetrathyridia of M. canislagopodis. Studies performed in other European countries have frequently confirmed Mesocestoides tetrathyridia in rodents of the genus Apodemus, for example in Poland (Zalesny and Hildebrand 2012), Bulgaria (Literák et al 2004), Sicily (Goüy de Bellocq et al 2003), Spain (Conn et al 2010), and Portugal (Eira et al 2006).…”

Molecular identification of Mesocestoides spp. from intermediate hosts (rodents) in central Europe (Poland)

“…However, the presence of metacestodes of Mesocestoides spp. or Mesocestoides lineatus have been reported in the helminth fauna of rodents (Bajer et al 2005;Behnke et al 2001;Behnke et al 2008;Conn et al 2010).…”

Natural infections of tetrathyridia ofMesocestoidesspecies in deer mice,Peromyscus maniculatus, from New Mexico

“…Conn (1986) and Conn et al (2002) examined Mesocestoides tetrathyridia both morphologically and ultrastructurally and noted marked differences between asexually proliferative and nonproliferative tetrathyridia. They have also reported nonproliferating Mesocestoides tetrathyridia from European rodents, although some of these do possess morphological aberrancies (Conn et al, 2010(Conn et al, , 2011. The present report provides important new information on the prevalence of asexuality among tetrathyridia and underscores the need for further study of this variation among metacestodes of this cosmopolitan genus.…”