Molecular identification of Ascaris lumbricoides and Ascaris suum recovered from humans and pigs in Thailand,Lao PDR,and Myanmar

Parasitology Research - Ascaris lumbricoides is the largest roundworm known from the human intestine while Ascaris suum is an internal parasite of pigs. Ascariasis, caused by Ascaris lumbricoides,...     

Sequence determination of a quadripartite dsRNA virus isolated from Aspergillus foetidus

Virus infection of Aspergillus foetidus was documented over 40 years ago and was one of the first mycovirus infections described in a filamentous fungus. The virus, named Aspergillus foetidus virus (AfV), contains at least two types of icosahedral particles, called AfV-fast (-F) and AfV-slow (-S) virions, based on their relative electrophoretic mobilities. Here, we report the complete nucleotide sequence of the AfV-F genome isolated from virions purified from the prototype isolate of the fungus. The AfV-F double-stranded (ds) RNA genome is tetra-segmented, and the plus strands of each of the four segments, but not the minus strands, are polyadenylated. The organisation and sequences of the four AfV-F dsRNAs are similar to those described for Alternaria alternata virus 1, which we propose is a member of an emerging mycovirus genus (“Alternavirus”) and family (“Alternaviridae”), which also includes AfV-F.     

Three Human Gnathostomiasis Cases in Thailand with Molecular Identification of Causative Parasite Species

Human gnathostomiasis is one of the important food-borne parasitic zoonoses. The disease is caused by a spirurid roundworm of the genus Gnathostoma. Here, we describe three parasitological confirmed cases of human gnathostomiasis, caused by Gnathostoma spinigerum, in a hospital in Thailand during 2004–2012. Clinical characteristics, treatment, and outcome of cases were revealed. Parasites were accidentally recovered from patients and morphologically identified as Gnathostoma species. Confirmed diagnosis and identification of causative parasite species was made by DNA extraction of the recovered worms, followed by a polymerase chain reaction (PCR) of the second internal transcribed spacer region (ITS2) of DNA and the partial cytochrome c oxidase subunit 1 (cox-1) gene. Sequences corresponding to ITS2 and cox-1 were similar to G. spinigerum. To our knowledge, this study represents the first molecular confirmation that recovered G. spinigerum is a causative agent of human infection in Thailand.     

A novel mycovirus from Aspergillus fumigatus contains four unique dsRNAs as its genome and is infectious as dsRNA

We report the discovery and characterization of a double-stranded RNA (dsRNA) mycovirus isolated from the human pathogenic fungus Aspergillus fumigatus, Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1), which reveals several unique features not found previously in positive-strand RNA viruses, including the fact that it represents the first dsRNA (to our knowledge) that is not only infectious as a purified entity but also as a naked dsRNA. The AfuTmV-1 genome consists of four capped dsRNAs, the largest of which encodes an RNA-dependent RNA polymerase (RdRP) containing a unique GDNQ motif normally characteristic of negative-strand RNA viruses. The third largest dsRNA encodes an S-adenosyl methionine–dependent methyltransferase capping enzyme and the smallest dsRNA a P-A-S–rich protein that apparently coats but does not encapsidate the viral genome as visualized by atomic force microscopy. A combination of a capping enzyme with a picorna-like RdRP in the AfuTmV-1 genome is a striking case of chimerism and the first example (to our knowledge) of such a phenomenon. AfuTmV-1 appears to be intermediate between dsRNA and positive-strand ssRNA viruses, as well as between encapsidated and capsidless RNA viruses.Mycoviruses with increasingly diverse genomes have been described in a wide range of fungi covering all four phyla of the true fungi: Ascomycota, Basidiomycota, Chytridiomycota, and Zygomycota. The more abundant mycoviruses with double-stranded RNA (dsRNA) genomes are generally classified into five major families: Totiviridae (nonsegmented, 4.6–7 kbp), Partitiviridae (2 segments, 1.4–2.3 kbp), Chrysoviridae (4 segments, 2.4–3.6 kbp), Reoviridae (10–12 segments, 0.7–5 kbp), all of which are conventionally encapsidated, Megabirnaviridae (2 segments, 7–9 kbp), and the proposed families “Quadriviridae” (4 segments, 3.7–4.9 kbp) and “Alternaviridae” (4 segments, 1.4–3.6 kbp) (1–8). The remaining six families (Alphaflexiviridae, Barnaviridae, Endornaviridae, Gammaflexiviridae, Hypoviridae, and Narnaviridae) accommodate single-stranded RNA (ssRNA) genomes, of which only three families (Alphaflexiviridae, Barnaviridae, and Gammaflexiviridae) form virus particles, whereas members of the remaining three virus families are unencapsidated and do not form typical virions. Two families (Metaviridae and Pseudoviridae) accommodate RNA reverse-transcribing genomes. A negative-strand RNA mycovirus (9) and a geminivirus-related DNA mycovirus (10) have also been identified, characterized, and sequenced.During routine screening for RNA viruses in the human fungal pathogen Aspergillus fumigatus, we discovered three dsRNA profiles in 366 clinical and environmental isolates ranging in size from ∼1.1 to 3.6 kbp (11). Two of the profiles were found to be representatives of respectively a chrysovirus nominated Aspergillus fumigatus chrysovirus (AfuCV) (12) and a partitivirus nominated Aspergillus fumigatus partitivirus 1 (AfuPV-1) (13). Here, we report the sequence and characterization of the remaining profile of four uncharacterized dsRNA segments, which constitute the genome of a completely novel mycovirus nominated Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1). In common with a number of recently described dsRNAs, AfuTmV-1 is an unconventional virus, in that it is not encapsidated but is apparently coated with a virus-encoded protein and may also be associated with or enveloped in colloidal cellular components (e.g., refs. 14 and 15). For the first time for a mycovirus, to our knowledge, we demonstrate that both AfuTmV-1 and its isolated dsRNA are infectious for fungal protoplasts. The unique sequences of the four AfuTmV-1 dsRNAs and the proposed roles of the proteins predicted from them in virus replication, including the combination of a capping enzyme and the RNA-dependent RNA polymerase (RdRP) on separate dsRNAs, strengthen the suggestion for the assignation of a new virus family where AfuTmV-1 would represent the prototype member.     

A New Population and Habitat for Neotricula aperta in the Mekong River of Northeastern Thailand: A DNA Sequence-Based Phylogenetic Assessment Confirms Identifications and Interpopulation Relationships

Neotricula aperta (Gastropoda: Pomatiopsidae), the snail intermediate host of Schistosoma mekongi, is found in Cambodia, Laos, and Thailand. We update information on the distribution of this species in the Mekong River and its tributary, the Mun River, in Thailand. DNA sequences of a portion of the mitochondrial cytochrome c oxidase subunit 1 were obtained from N. aperta collected from different locations and used to confirm species and strain identities. Specimens of the β-strain were found in the Mun River, whereas specimens of the γ-strain were found in the Mekong River. The γ-strain (with molecular confirmation of identity) is newly reported from Nong Khai Province, where it occurred in a habitat novel for this species: under paving slabs instead of under natural bed rocks, where agal aufwuchs is extensively located on the islet in the middle of the Mekong River. The new location is approximate 400 km upstream from the nearest previously known site for this species.     

Immuno-proteomic analysis of Trichinella spiralis,T. pseudospiralis,and T. papuae extracts recognized by human T. spiralis-infected sera

Parasitology Research - The present study explored potentially immunogenic proteins of the encapsulated (Trichinella spiralis) and non-encapsulated (T. pseudospiralis, T. papuae) species within the...     

Factors related to tobacco use among middle school students in China

The objectives of this study were to determine the status of tobacco use among middle school students in China, and to identify factors related to tobacco use. The study was conducted in December 2009. An ecological model was used to formulate the conceptual framework of the study. Three thousand two hundred twenty-one middle school students aged 12-17 years were selected by three stage stratified cluster sampling. Data were collected by self-completed questionnaires and interviews. The prevalence of current smoking was 10.6%; 16.2% among males and 4.3% among females. The prevalence of ever having smoked was 19.7%, 25.3% among males and 13.4% among females. Zero point seven percent of middle school students used other forms of smoked tobacco products other than cigarettes. Multinomial logistical regression analysis found gender, age, knowledge, attitude, life skills, self-concept, parental smoking, friends smoking, friends attitudes toward smoking, peer pressure, family rules, availability of cigarettes, tobacco-free school environment, smoking intervention program, community tobacco control activities, and tobacco control policies had significant associations with smoking behavior. Structural equation modeling (SEM) analysis found intrapersonal factors had direct relationships with smoking behavior among smoking middle school students. Interpersonal factors, organizational factors and policies had indirect relationships with smoking behavior, and through intrapersonal factors affected smoker behavior among middle school smoking students.