Infection with the roundworm Angiostrongylus cantonensis is the main cause of eosinophilic meningitis worldwide. The underlying molecular basis of the various pathological outcomes in permissive and non-permissive hosts infected with A. cantonensis remains poorly defined. In the present study, the histology of neurological disorders in the central nervous system (CNS) of infected rats was assessed by using hematoxylin and eosin staining. Quantitative reverse transcription polymerase chain reaction (RT-qPCR), western blot and immunofluorescence (IF) were used in evolutions of the transcription and translation levels of the apoptosis-, necroptosis-, autophagy-, and pyroptosis-related genes. The distribution of apoptotic and necroptotic cells in the rat hippocampus and parenchyma was further detected using flow cytometry, and the features of the ultrastructure of the cells were examined by transmission electron microscopy (TEM). The inflammatory response upon CNS infection with A. cantonensis evolved, as characterized by the accumulation of a small number of inflammatory cells under the thickened meninges, which peaked at 21 days post-infection (dpi) and returned to normal by 35 dpi. The transcription levels and translation of caspase-2, caspase-8, RIP1 and RIP3 increased significantly at 21 and 28 dpi but decreased sharply at 35 dpi compared to those in the normal control group. However, the changes in the expression of caspase-1, caspase-3, caspase-11, Beclin-1 and LC3B were not obvious, suggesting that apoptosis and necroptosis but not autophagy or pyroptosis occurred in the brains of infected animals at 21 and 28 dpi. The results of RT-qPCR, western blot analysis, IF, flow cytometry and TEM further illustrated that necroptosis and caspase-2-mediated apoptosis occurred in astrocytes and neurons but not in microglia in the parenchyma and hippocampus of infected animals. This study provides the first evidence that neuronal and astrocytic necroptosis and caspase-2-mediated apoptosis are induced by A. cantonensis infection in the parenchymal and hippocampal regions of rats at 21 and 28 dpi but these processes are negligible at 35 dpi. These findings enhance our understanding of the pathogenesis of A. cantonensis infection and provide new insights into therapeutic approaches targeting the occurrence of cell death in astrocytes and neurons in infected patients.

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Necroptosis and Caspase-2-Mediated Apoptosis of Astrocytes and Neurons, but Not Microglia, of Rat Hippocampus and Parenchyma Caused by Angiostrongylus cantonensis Infection.

Helminth fauna of myomorh rodents (Rodentia, Myomorha) in the Central Chernozem State Nature Reserve.

. Kirillova NYu, Kirillov AA, Ruchin AB, Trukhachev MV. 2020. Helminth fauna of Microtus cf. arvalis (Rodentia, Cricetidae) in Russia and adjacent countries. Biodiversitas 21: 1961-1979. The helminth fauna of voles of the Microtus cf. arvalis group is reviewed focusing on the Russian fauna and that of adjacent territories. In total, 61 helminth species have been recorded in these rodents: Trematoda-14, Cestoda-21, Nematoda-25, Acanthocephala-1. The diversity of the helminth community of the common vole is due to the wide species range and abundance of this rodent. M. arvalis is the final host for most of the parasites recorded from this host species. Only 10 cestodes and trematodes species use common voles as intermediate and paratenic hosts. The core of this voles’ helminth fauna is formed by common species that parasitize many different rodent species. The helminth fauna of the common vole has been most intensively studied in Russia, where 45 species of parasitic worms have been recorded in rodents. The similarity of the helminth fauna of the common vole from different study regions is determined by both the geographical proximity of the research areas and the broad distribution of most of the M. cf. arvalis helminth species.

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Helminth fauna of Microtus cf. arvalis (Rodentia, Cricetidae) in Russia and adjacent countries

The helminth fauna of the Northern white-breasted hedgehog Erinaceus roumanicus was studied in the Republic of Mordovia (Russia) for the first time. In total, 9 species of helminths were found in 23 studied hedgehogs: Trematoda—Isthmiophora melis, Strigea strigis (metacercaria); Cestoda—Hymenolepis erinacei; Nematoda—Aonchotheca erinacei, Physaloptera clausa, Crenosoma striatum, Physocephalus sexalatus (juvenile), Agamospirura minuta (juvenile); and Acanthocephala—Nephridiorhynchus major. Four parasite species (the trematode I. melis, nematodes P. sexalatus, A. minuta, and the acanthocephalan N. major) were found in hedgehogs for the first time in Russia. An overview of the helminth fauna of four species of Erinaceus hedgehogs inhabiting the Palearctic region is given. A total of 54 parasite species were recorded across Erinaceus europaeus, E. roumanicus, E. concolor and E. amurensis: 14 trematodes, 6 cestodes, 27 nematodes, and 7 acanthocephalans. Among all the studied species of hedgehogs, E. europaeus (35 species) and E. roumanicus (36) have the richest helminth faunas. The diversity of the parasite communities of Erinaceus spp. is due to the wide distribution and varied diet of these mammals. Most of the helminths found in hedgehogs are transmitted along trophic chains. Hedgehogs are the final hosts for 39 species of parasites. For 15 helminth species, Erinaceus spp. are paratenic hosts. The majority of the hedgehog’s helminth fauna is formed by host-specific parasites, of which there are 13 species. Most of the hedgehog’s parasites in the Palaearctic are facultative (non-specific) species that parasitize in various vertebrate species. The helminth fauna of Erinaceus hedgehogs is most studied in Russia and Belarus, where 17 species of parasites are found in each country. The comparative analysis of the helminth faunas of Erinaceus spp. from various regions showed, on the one hand, the originality of the helminth fauna of each hedgehog species and, on the other, the similarity of the helminth fauna of these insectivores from various countries of the Palaearctic. These features are caused by similar lifestyles and diet peculiarities of every hedgehog species in various regions of the Palaearctic. A total of 12 of the 54 helminth species found in hedgehogs have medical and veterinary significance as causative agents of dangerous helminthiasis.

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Helminths of Erinaceus roumanicus (Eulipotyphla, Erinaceidae) in Mordovia (Russia) with an Overview of Helminth Fauna of Erinaceus spp. Inhabiting the Palaearctic Region

An overview of the parasites, bacteria and viruses of Glis glis (Rodentia, Gliridae) inhabiting the Western Palearctic is given. A total of 85 articles published from 1895 to 2021 were reviewed and analysed in our study. According to the literature’s data, 104 species associated with G. glis are recorded: 4 viruses, 8 Protozoa, 6 Cestoda, 6 Trematoda, 4 Nematoda, 1 Heteroptera, 2 Anoplura, 39 Siphonaptera and 34 Acari. The most studied group is ectoparasites. To a lesser extent, parasitic worms in G. glis were studied. There is very little data about the dormouse protozoans and viruses. The most studied parasites, viruses and protozoans of G. glis are in Germany, where 21 species were noted. The largest number of parasites was found in the dormouse in Russia (22), but of two groups only: helminths and ectoparasites. Only 20 out of 104 parasite species recorded in G. glis are host-specific. Most parasites (60 species) found in G. glis have a Palaearctic and cosmopolitan distribution. Three viruses, six species of protozoa and three helminths have veterinary and medical significance as potential pathogens of dangerous zoonoses. Also, many species of fleas, mites and ticks found on G. glis are vectors of a number of dangerous vector-borne diseases in humans and domestic and wild animals.

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Parasites, Bacteria and Viruses of the Edible Dormouse Glis glis (Rodentia: Gliridae) in the Western Palaearctic

This review summarizes known data on the species composition of nematodes in 24 species of rodents inhabiting the territory of Armenia (South of Lesser Caucasus). The studied rodents include members of some cosmopolitan species (Mus musculus, Rattus norvegicus, Rattus rattus), as well as endemic and narrow-areal species (Meriones vinogradovi, Spermophilus xanthoprymnus, Microtus schidlovskii, Mesocricetus brandti, Sciurus anomalus). The taxonomical identity of the nematode species reported by previous authors is discussed with regard to present knowledge about helminth fauna of rodents. Our review concludes that 34 nematode species are present in rodents in Armenia, five of which are identified for the first time in rodents from the territory of Armenia, and three of which (Trichinella spiralis, Trichostrongylus colubriformis, Trichostrongylus skrjabini) are able to parasitize humans.

Sergey O Movsesyan

Papers

Nematodes of rodents of Armenia