A novel genotype of Cryptosporidium muris from large Japanese field mice, Apodemus speciosus

Abstract

Cryptosporidium muris-like oocysts were isolated from large Japanese field mice, Apodemus speciosus. Morphologically, these oocysts resembled those obtained from a C. andersoni Kawatabi isolate but were smaller in size than those from a C.muris isolate. Following oral inoculation of the oocysts into large Japanese field mice and SCID mice, developing stages were found in the stomach epithelium. The infectivity of the isolate to wild and laboratory mice was slightly different from that of C.muris. DNA sequences of the 18S ribosomal RNA (rRNA) gene of the isolate were not identical to those of any known Cryptosporidium spp.; however, phylogenetic analysis indicated that the isolate was a member of the C.muris cluster. Differences between the isolate and C. muris are not significant at this point; therefore, we propose that this isolate is a novel genotype of C.muris and denote it as C. muris Japanese field mouse genotype.

Development of a Multilocus Sequence Tool for Typing Cryptosporidium muris and Cryptosporidium andersoni

“…A parasite identical to the C. muris East African mole rat isolate was previously identified in an eastern gray squirrel in New York (6), suggesting that this parasite is probably widespread. A C. muris isolate from Japanese field mice was also shown to have minor differences in mouse infectivity and the sequence of the SSU rRNA gene from other C. muris isolates (16). Thus, genetic and biological diversities exist in C. muris, and with the inclusion of more genetic loci and samples from a wide range of hosts and geographical areas, the MLST approach developed in this study should be useful in elucidating the genetic basis for the difference in host specificity among C. muris isolates and in examining the spread of the parasite in geographically isolated areas such as the continent of Australia.…”

“…Phylogenetic relationships among subtypes of C. muris, the C. muris variant, and C. andersoni as assessed by a neighbor-joining analysis of the concatenated nucleotide sequences of four microsatellite and minisatellite loci (MS1, MS2, MS3, and MS16), using distance calculated by the Kimura two-parameter model. 3 and (GAACGA GATAGG) [14][15][16][17][18] (TAAAGAGAGAGA) 6 and (GAACGAGATAGG) 14 (TAAAGGGCGAGA) 3 and (GAACGAGATAGG) 13-14 CM-MS2 (CCATATCCC) [3][4] and (CCATACCTC) 3 (CCCATTCCT) 4 (CCATACCTC) 10-11 CM-MS3 (TGTTGG) [8][9] and (GCTGCA) 6 (TGTTGG) 7 and (TGC) 10 (TGTTGGTGTTGCTGT) 2 and (TGCTGCAGCTGC) 2-3 CM-MS16…”

“…Cryptosporidium muris is well known to have broad host specificity. In addition to various rodent species, natural C. muris infections have been documented for pigs, Bactrian camels, giraffes, dogs, cats, nonhuman primates, seals, bilbies, and tawny frogmouth (3,16,17,20,22,26,27,29,32,34,37,38,40,44). In contrast, C. andersoni is mostly a parasite of cattle, having been found only occasionally in other animals such as Bactrian camels, sheep, and goats.…”

Novel Cryptosporidium Genotype in Wild Australian Mice ( Mus domesticus )

“…There have been few studies conducted on the epidemiology of Cryptosporidium in wild mice; however, it is important to understand if mice are a reservoir of infection for humans and animals. Studies in different geographical areas have reported prevalence rates ranging from 5.0% to 39.2% in wild rodents, but most have relied on morphology for identification (2)(3)(4)(20)(21)(22).The limited molecular characterization studies that have been conducted on rodents have identified eight species/genotypes: (i) mouse genotype I, which has been identified in mice and rats and in prairie bison in Spain, Portugal, the United Kingdom, Australia, and the United States (1, 16; L. Xiao et al, unpublished data) and to date has not been identified in humans; (ii) the zoonotic Cryptosporidium parvum, which was detected in mice trapped near sheep grazing pastures in Victoria, Australia (16); (iii) Cryptosporidium muris, which infects a range of rodents and is generally not zoonotic but which can infect other hosts, including dogs, hamsters, guinea pigs, chipmunks, rabbits, lambs, cats, and humans (4,9,10,11,18,19); (iv) a novel genotype detected in one wood mouse (Apodemus sylvaticus) sample from the Czech Republic (8); (v) Cryptosporidium meleagridis, isolated from a brown rat (Rattus norvegicus) in Japan (isolate BR5) (13); (vi) eight isolates from brown rats in Japan that clustered with sequences denoted W19 and W19 variants found in New York storm water (12, 13); (vii) three isolates from brown rats in Japan identical to recently described snake isolate 2162 (AY268584) (13, 25); and (viii) another isolate from brown rats in Japan which showed 100% identity with isolates from nonhuman primates in Sri Lanka (EF446679) (5, 13).These studies indicate that the majority of wild mice characterized to date do not carry zoonotic species of Cryptosporidium. …”

Discrimination of Cryptosporidium species by denaturing gradient gel electrophoresis

“…As reference strains, we used oocysts of C. parvum HNJ-1 (Masuda et al 1991), C. muris RN66 (Iseki 1986), C. andersoni Kawatabi strain (Satoh et al 2003), and C. muris Japanese field mouse genotype (Hikosaka and Nakai 2005). These oocysts had been passaged and maintained in the severe combined immunodeficiency (SCID) mice in our laboratory, and the oocysts were purified from the fecal sample of the experimental infected SCID mice using sugar floatation method (Nakai et al 2004).…”