Molecular phylogeny of the pinworms of mice, rats and rabbits, and its use to develop molecular beacon assays for the detection of pinworms in mice

Genetic diversity of Syphacia Seurat, 1916 (Nematoda: Oxyuridae) across the hybrid zone of their rodent hosts in Russia

The genetic diversity of Syphacia nematodes (intestinal parasites of rodents) was studied in the hybrid zone of two sister species of common voles, Microtus arvalis and Microtus obscurus, in the Oka River valley, east of Moscow. Syphacia nematodes of other rodent species (Microtus rossiaemeridionalis, Alexandromys oeconomus, Sylvaemus uralensis, and Apodemus agrarius) that inhabit the area were also studied. Phylogenetic trees for the studied nematodes were inferred from the analysis of nuclear ITS1+5.8S+ITS2, LSU rDNA, and mitochondrial CO1 gene partial sequences. Syphacia nematodes of the studied area form three well-defined clades in the phylogenetic tree of this genus. Morphological analysis revealed similarities between the obtained sequences with those of known Syphacia species from the GenBank database, which enabled identifying these three clades up to the species level: S. montana, S. agraria, and S. frederici. Russian haplotypes of Syphacia are different from West European and East Asian haplotypes with pronounced genetic distances. A high level of specificity was reported for two of these three species (S. frederici, only in Sylvaemus uralensis; S. agraria, only in Apodemus agrarius). S. montana was found in different species of voles. Remarkably, S. montana specimens from M. arvalis and M. obscurus were genetically uniform, while S. montana, specimens from hybrids between these two species formed a separate clade distant from those originating from non-hybridised hosts.

First record of third-stage Terranova larval type II (Nematoda, Anisakidae) in the common ponyfish Leiognathus equulus Forsskål

The current study was carried out to investigate the natural occurrence of nematode parasites that infect the common ponyfish Leiognathus equulus from Jeddah, Saudi Arabia. Third-stage nematode larvae were found to be encysted in the peritoneum of the fish studied, with the prevalence of infection being 25%. Light microscopy revealed that this parasite belongs to the Anisakidae family within the genus Terranova by having all the generic characteristic features. Based on the intestinal caecum ratio to the length of the ventriculus being 2:1, the excretory pore with ventral location below the boring tooth, the body ended with a conical tail; the larvae found in the present study were identified as Terranova larval type. To validate its taxonomic position within Anisakidae, this Terranova species' morphological features were combined with the ITS-1 gene's molecular analysis. It demonstrated sequence similarities 94.38-76.57% with taxa of Anisakidae. A preliminary genetic comparison between the present parasite and other ascaridoids placed it as a putative sister taxon to the previously described Terranova species. The first record of the current anisakid larvae in the common ponyfish with a unique genetic sequence for the partial sequence of the ITS-1 gene was observed in this study. Its taxonomic position was confirmed in Anisakidae.

Molecular characterization of cosmopolitan and potentially co-invasive helminths of commensal, murid rodents in Gauteng Province, South Africa

Concurrent studies of helminth parasites of introduced and native rodent species are few and miss the opportunity to identify potential co-invasive parasite species. This study employed molecular tools to infer the phylogeny and elucidate the origin of potentially co-invasive parasites of commensal, murid rodents by assessing introduced Rattus norvegicus, Rattus rattus, Rattus tanezumi, and native Mastomys coucha in Gauteng Province, South Africa. Genotypes of Nippostrongylus brasiliensis recovered from R. norvegicus are nearly identical to those recovered from elsewhere in the world. The pinworms, Aspiculurus tetraptera, recovered from introduced R. tanezumi and R. rattus, Syphacia muris recovered from R. tanezumi, and Syphacia obvelata recovered from indigenous M. coucha have affiliations to those recovered of laboratory rodents from the USA and China. Syphacia obvelata was previously only known as a commensal endoparasite of laboratory rodents, and the S. muris genotype recovered from R. tanezumi in this study shows an affiliation to a genotype recovered from the same host species in Indonesia which is part of the native range. The study emphasizes the need for surveillance of potential co-invasive species and contributes in documenting genetic diversity of endoparasites of well-known hosts.

Pinworm detection in mice with immunodeficient (NOD SCID) and immunocompetent (CD-1 and Swiss) soiled bedding sentinels in individually ventilated cage systems

Sentinel exposure to soiled bedding is frequently used for health monitoring of mice housed in individually ventilated cage systems (IVCS). Despite its advantages, the use of soiled bedding sentinels (SBSs) is far for being a reliable method. Two studies were conducted to evaluate the sensitivity of immunodeficient SBSs NOD.CB17-Prkdc(scid)/NCrHsd (NOD SCID) against two immunocompetent outbred strains, Hsd:ICR (CD-1) and RjOr1:Swiss (Swiss) to pinworm detection in IVCS-housing. Four different diagnostic methods were used: perianal tape test, fecal flotation, plate method and histology. Positivity was considered if at least one of the techniques used was positive. In the first study NOD SCID were more sensitive than CD-1 SBSs (P < 0.05), and except for the fecal flotation test performed at week 6, all the diagnostic methods were more sensitive with NOD SCID mice (P < 0.05). In the second study differences between the Swiss and NOD SCID mice were less obvious (P = 0.08). When compared separately, the different diagnostic methods, except for the fecal flotation test, were all more sensitive in the NOD SCID mice (P < 0.05). In addition, the anal tape test in the Swiss SBSs was more sensitive at week 7 than at week 15 (P < 0.05). In conclusion, combining various diagnostic techniques and samplings at week 7 post-exposure with non-invasive methods increases the rate of pinworm detection. Immunodeficient SBSs showed higher sensitivity than immunocompetent ones. Thus, use of immunodeficient SBSs is highly recommended in health control protocols.

Molecular phylogenetic analysis of Enterobius vermicularis and development of an 18S ribosomal DNA-targeted diagnostic PCR

We genetically characterized pinworms obtained from 37 children from different regions of Germany and established new species-specific molecular diagnostic tools. No ribosomal DNA diversity was found; the phylogenetic position of Enterobius vermicularis within the Oxyurida order and its close relationship to the Ascaridida and Spirurida orders was confirmed.

Design of a room-temperature phosphorescence-based molecular beacon for highly sensitive detection of nucleic acids in biological fluids

Ultrasensitive fluorescent analysis or monitoring of significant molecules in complex samples is important for many biological studies, clinical diagnosis, and forensic investigations, the major obstacle for which is the background signals from ubiquitous endogenous fluorescent components of the environments. Herein, a room-temperature phosphorescence (RTP)-based molecular beacon (MB), employing a Eu(3+) complex of chlorosulfonylated tetradentate β-diketone (L) and the quencher BHQ-2, was engineered for highly sensitive detection of DNA sequences in biological fluids. Complexation of Eu(3+) with the ligand L formed a strongly luminescent complex EuL(2). But when EuL(2) and BHQ-2 were labeled to two ends of a DNA molecule with hairpin structure, the luminescence of EuL(2) was quenched by BHQ-2 due to the stem-closed conformation of the beacon. Due to very low background luminescence from the probe molecule, >200-fold signal enhancement was achieved when nanomolar target sequence was introduced. This sensitivity is about 20-fold higher than the level achieved with conventional fluorescence-based molecular beacons. Furthermore, because the Eu(3+) complex has a much longer luminescence lifetime (≈0.8 ms) than that of the background (<10 ns), RTP measurements were used to directly detect as low as 500 pM DNA in cell media quantitatively without any sample pretreatment.