Morphological and molecular characteristics of a new species of Pasteuria parasitic on Meloidogyne ardenensis

A species of the hyper-parasitic bacterium Pasteuria was isolated from the root-knot nematode Meloidogyne ardenensis infecting the roots of ash (Fraxinus excelsior). It is morphologically different from some other Pasteuria pathogens of nematodes in that the spores lack a basal ring on the ventral side of the spore and have a unique clumping nature. Transmission electron microscopy (TEM) showed that the clumps of spores are not random aggregates but result from the disintegration of the suicide cells of the thalli. Sporulation within each vegetative mycelium was shown to be asynchronous. In addition to the novel morphological features 16S rRNA sequence analysis showed this to be a new species of Pasteuria which we have called P. hartismeri. Spores of P. hartismeri attach to juveniles of root-knot nematodes infecting a wide range of plants such as mint (Meloidogyne hapla), rye grass (unidentified Meloidogyne sp.) and potato (Meloidogyne fallax). (c) 2007 Elsevier Inc. All rights reserved.

Genome sequences of the human body louse and its primary endosymbiont provide insights into the permanent parasitic lifestyle

As an obligatory parasite of humans, the body louse (Pediculus humanus humanus) is an important vector for human diseases, including epidemic typhus, relapsing fever, and trench fever. Here, we present genome sequences of the body louse and its primary bacterial endosymbiont Candidatus Riesia pediculicola. The body louse has the smallest known insect genome, spanning 108 Mb. Despite its status as an obligate parasite, it retains a remarkably complete basal insect repertoire of 10,773 protein-coding genes and 57 microRNAs. Representing hemimetabolous insects, the genome of the body louse thus provides a reference for studies of holometabolous insects. Compared with other insect genomes, the body louse genome contains significantly fewer genes associated with environmental sensing and response, including odorant and gustatory receptors and detoxifying enzymes. The unique architecture of the 18 minicircular mitochondrial chromosomes of the body louse may be linked to the loss of the gene encoding the mitochondrial single-stranded DNA binding protein. The genome of the obligatory louse endosymbiont Candidatus Riesia pediculicola encodes less than 600 genes on a short, linear chromosome and a circular plasmid. The plasmid harbors a unique arrangement of genes required for the synthesis of pantothenate, an essential vitamin deficient in the louse diet. The human body louse, its primary endosymbiont, and the bacterial pathogens that it vectors all possess genomes reduced in size compared with their free-living close relatives. Thus, the body louse genome project offers unique information and tools to use in advancing understanding of coevolution among vectors, symbionts, and pathogens.

Mites Parasitic on Australasian and African Spiders Found in the Pet Trade; a Redescription of Ljunghia pulleinei Womersley

Parasitic mites associated with spiders are spreading world-wide through the trade in tarantulas and other pet species. Ljunghia pulleinei Womersley, a mesostigmatic laelapid mite originally found in association with the mygalomorph spider Selenocosmia stirlingi Hogg (Theraphosidae) in Australia, is redescribed and illustrated on the basis of specimens from the African theraphosid spider Pterinochilus chordatus (Gersta¨cker) kept in captivity in the British Isles (Wales). The mite is known from older original descriptions of Womersley in 1956; the subsequent redescription of Domrow in 1975 seems to be questionable in conspecificity of treated specimens with the type material. Some inconsistencies in both descriptions are recognised here as intraspecific variability of the studied specimens. The genus Arachnyssus Ma, with species A. guangxiensis (type) and A. huwenae, is not considered to be a valid genus, and is included in synonymy with Ljunghia Oudemans. A new key to world species of the genus Ljunghia is provided.

Assessment of the anthelmintic activity of medicinal plant extracts and purified condensed tannins against free-living and parasitic stages of Oesophagostomum dentatum

Background: Plant-derived condensed tannins (CT) show promise as a complementary option to treat gastrointestinal helminth infections, thus reducing reliance on synthetic anthelmintic drugs. Most studies on the anthelmintic effects of CT have been conducted on parasites of ruminant livestock. Oesophagostomum dentatum is an economically important parasite of pigs, as well as serving as a useful laboratory model of helminth parasites due to the ability to culture it in vitro for long periods through several life-cycle stages. Here, we investigated the anthelmintic effects of CT on multiple life-cycles stages of O. dentatum. Methods: Extracts and purified fractions were prepared from five plants containing CT and analysed by HPLC-MS. Anthelmintic activity was assessed at five different stages of the O. dentatum life cycle; the development of eggs to infective third-stage larvae (L3), the parasitic L3 stage, the moult from L3 to fourth-stage larvae (L4), the L4 stage and the adult stage. Results: Free-living larvae of O. dentatum were highly susceptible to all five plant extracts. In contrast, only two of the five extracts had activity against L3, as evidenced by migration inhibition assays, whilst three of the five extracts inhibited the moulting of L3 to L4. All five extracts reduced the motility of L4, and the motility of adult worms exposed to a CT-rich extract derived from hazelnut skins was strongly inhibited, with electron microscopy demonstrating direct damage to the worm cuticle and hypodermis. Purified CT fractions retained anthelmintic activity, and depletion of CT from extracts by pre-incubation in polyvinylpolypyrrolidone removed anthelmintic effects, strongly suggesting CT as the active molecules. Conclusions: These results suggest that CT may have promise as an alternative parasite control option for O. dentatum in pigs, particularly against adult stages. Moreover, our results demonstrate a varied susceptibility of different life-cycle stages of the same parasite to CT, which may offer an insight into the anthelmintic mechanisms of these commonly found plant compounds.

Rotavirus Gastroenteritis in Children in 4 Regions in Brazil: A Hospital-Based Surveillance Study

Background. Rotavirus is a major cause of gastroenteritis in children. Knowledge of rotavirus genotypes is important for vaccination strategies. Methods. During 2005-2006, rotavirus surveillance studies were conducted in Sao Paulo, Salvador, Goiania, and Porto Alegre, Brazil. Stool samples were collected from children <5 years of age who had diarrhea and were screened by the Rotaclone Enzyme Immunoassay for the presence of rotavirus. Confirmed rotavirus-positive samples were characterized for P and G genotypes by reverse-transcriptase polymerase chain reaction. Results. A total of 510 stool samples were collected. Of these, 221 (43.3%) were positive for rotavirus. Overall, G9 was the predominant G type, followed by G2, and G1; P[4] and P[8] were the predominant P types. The most frequent G/P genotype combination detected was G2P[4], followed by G9P[8], G9P[4], and G1P[8]. G2P[4] was the predominant type in Goiania and Salvador; G9P[8] and G1P[8] were predominant in Sao Paulo and Porto Alegre, respectively. Conclusions. The prevalence, seasonality, and genotype distribution of rotavirus infection varied in different regions in Brazil. With immunization programs, continuous monitoring of rotavirus types is important to detect novel and emerging strains.

Phylogeographical, ecological and biological patterns shown by nuclear (ssrRNA and gGAPDH) and mitochondrial (Cyt b) genes of trypanosomes of the subgenus Schizotrypanum parasitic in Brazilian bats

The genetic diversity and phylogeographical patterns of Trypanosoma species that infect Brazilian bats were evaluated by examining 1043 bats from 63 species of seven families captured in Amazonia, the Pantanal, Cerrado and the Atlantic Forest biomes of Brazil. The prevalence of trypanosonne-infected bats, as estimated by haemoculture, was 12.9%, resulting in 77 Cultures of isolates, most morphologically identified as Trypanosoma cf. cruzi, classified by barcoding using partial sequences from ssrRNA gene into the subgenus Schizotrypanum and identified as T. cruzi (15), T cruzi marinkellei (37) or T. cf. dionisii (25). Phylogenetic analyses using nuclear ssrRNA, glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) and mitochondrial cytochrome b (Cyt b) gene sequences generated three clades, which clustered together forming the subgenus Schizotrypanum. In addition to vector association, bat trypanosomes were related by the evolutionary history, ecology and phylogeography of the bats. Tryponosoma cf. dionisii trypanosomes (32.4%) infected 12 species from four bat families captured in all biomes, from North to South Brazil, and clustered with T. dionisii from Europe despite being separated by some genetic distance. Trypanosoma cruzi marinkellei (49.3%) was restricted to phyllostomid bats from Amazonia to the Pantanal (North to Central). Trypanosoma cruzi (18.2%) was found mainly in vespertilionid and phyllostomid bats from the Pantanal/Cerrado and the Atlantic Forest (Central to Southeast), with a few isolates from Amazonia. (C) 2009 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Recent advances of metal binding protein lactoferrin as an anti-microbial agent

Lactoferrin (Lf) is present in milk and gland secretions and serve as an antimicrobial function. Insufficient amounts of Lf in some secretions also appear to correlate with certain health problems. Protection against gastroenteritis is the most likely biologically relevant activity of lactoferrin. Multiple in vitro and animal studies have shown a protective effect of lactoferrin on infections with enteric microorganisms, including rotavirus, Giardia, Shigella, Salmonella and the diarrheagenic Escherichia coli. Lactoferrin has two major effects on enteric pathogens: it inhibits growth and it impairs function of surface expressed virulence factors thereby decreasing their ability to adhere or to invade mammalian cells. Lf also inhibits several species of fungi and certain parasites. This review covers the role of Lf in clearing the parasitic infections. The mechanism by which lactoferrin inhibits some parasites may be via stimulation of the process of phagocytosis, whereby immune cells engulf and digest foreign organisms. Trichomonas vaginalis is a protozoan responsible for the number one, non-viral sexually transmitted disease. In this review, we also discussed the role of Lf in cervical infections.

Morphometric and molecular characterization of the species of Uncinaria Frölich, 1789 (Nematoda) parasitic in the Australian fur seal Arctocephalus pusillus doriferus (Schreber), with notes on hookworms in three other pinniped hosts

This study presents morphological and molecular data on hookworms from the Australian fur seal Arctocephalus pusillus doriferus (Schreber) currently identified in Australian waters as Uncinaria hamiltoni Baylis, 1933. Additional specimens from the Australian sea lion Neophoca cinerea (Péron) and the New Zealand fur seal Arctocephalus forsteri (Lesson) from Australia, and the Southern elephant seal Mirounga leonina (Linnaeus) from Antarctica, were included. Using the internal transcribed spacer (ITS), hookworms from A. p. doriferus, N. cinerea and A. forsteri were found to be genetically similar but distinct from Uncinaria spp. found in M. leonina from Antarctica, as well as from Zalophus californianus (Lesson) and Callorhinus ursinus (Linnaeus) from California. Few morphological differences were detected between these taxa.