Infections of Two Isthmiophora Species (Digenea: Echinostomatidae) in Wild Mammals from Republic of Korea with Their Morphological Descriptions

Abstract

<i>Isthmiophora</i> <i>hortensis</i> (Digenea: Echinostomatidae) is a dominant echinostome in animal reservoir hosts and humans in the Republic of Korea (Korea). We intended to investigate the infection status with this echinostome species in the several species of wild animals and describe the morphological characteristics in the faunistic view point. A total of 175 animal carcasses belonging to 3 families, i.e., Canidae, Felidae and Mustelidae, were collected from the southern regions of Korea from March 2010 to July 2017. <i>Isthmiophora</i> spp. worms were recovered from the small intestines of each animal under a stereomicroscope after washing of intestinal contents. <i>Isthmiophora</i> <i>hortensis</i> was recovered from 4 species of wild carnivores, i.e., <i>Nyctereutes</i> <i>procyonoides</i> (3/107: 2.8%), <i>Mustela</i> <i>sibirica</i> (11/31: 35.5%), <i>Meles</i> <i>lucurus</i> (2/3: 33.3%) and <i>Martes</i> <i>flavigula</i> (1/2: 50%). The other 3 carnivores comprising stray dogs, cat and leopard cat were negative for <i>I</i>. <i>hortensis</i> infection (0/2, 0/10 and 0/12, respectively). Specimens obtained from the <i>Lutra</i> <i>lutra</i> (6/8: 75%) were identified as a distinct species, <i>I</i>. <i>inermis</i>, by morphological comparison. <i>Isthmiophora</i> <i>inermis</i> has thinner body, elongate testes and different anterior limits of vitelline fields. Detailed morphological descriptions and comparisons with the morphological characteristics are provided. Conclusively, it was confirmed for the first time that 3 species of mustelid mammals, i.e., <i>M</i>. <i>sibirica</i>, <i>M</i>. <i>lucurus</i>, and <i>M</i>. <i>flavigula</i>, are to be the new definitive hosts of <i>I</i>. <i>hortensis</i> in Korea. Additionally, <i>I</i>. <i>inermis</i> is to be newly added in the Korean echinostome fauna.

Helminths in Invasive Raccoons (Procyon lotor) from Southwest Germany

“…Unlike other representatives in the Echinostomatidae family, Isthmiophora spp. exclusively infest mammals’ intestinal tract during their adult phase [ 85 ]. So far, over 30 species of vertebrates, including humans, have been identified as final hosts [ 84 , 85 ].…”

Diversity of fecal parasitomes of wild carnivores inhabiting Korea, including zoonotic parasites and parasites of their prey animals, as revealed by 18S rRNA gene sequencing

“…The detection of Isthmiophora species seems reasonable because the Isthmiophora genus includes fish parasites ( Chai and Jung, 2019 ). In fact, it has been reported that several species of Isthmiophora have been detected in carcasses of Eurasian otters, such as Isthmiophora inermis in Korea ( Choe et al, 2019 ) and Isthmiophora melis in Denmark ( Takeuchi-Storm et al, 2021 ). Additionally, the Isthmiophora genus, including I. hortensis , has been reported to be prevalent in wildlife, especially mustelids, in Korea ( Choe et al, 2019 ).…”

Development of the head collar and collar spines during the larval stages of Isthmiophora hortensis (Digenea: Echinostomatidae)

“…Psilorchis hominis ) [ 18 , 19 ]. In Korea, the existence of I. hortensis [ 1 – 3 ], I. inermis (differs from I. hortensis in having a slender body, elongated testes, and short anterior limit of vitellaria) [ 20 ], and an unidentified 27-collar-spined echinostome [ 21 ] (suggested to be I. hortensis ) has been reported. The species involved in our experiment was confirmed to be I. hortensis by obtaining adult flukes from experimental rats infected with metacercariae (data not shown).…”