Onchocerca dewittei japonica n. subsp., a common parasite from wild boar in Kyushu Island, Japan

We describe Onchocerca dewittei japonica n. subsp. from the Japanese wild boar, Sus scrofa leucomystax, in Oita, Kyushu Island, where all seven animals examined were found to be infected. This study began with efforts to identify the causative species in a recent case of zoonotic onchocerciasis. Compared with Onchocerca dewittei dewittei from Sus scrofa jubatus in Malaysia, which was reexamined here, our new subspecies has much greater space between the ridges on the females. In addition, its microfilariae (from uteri) are shorter (192-210 microns compared with 228-247 microns), and only the posterior third of the microfilarial body is coiled, instead of the entire body. The Onchocerca species parasitic in suids (these two subspecies and O. ramachandrini from the warthog in the Ethiopian region) form a group sharing several characters. Among the most unusual characters are the body swellings (a specialized apparatus for mating, known in only a few other genera). In addition, longitudinal cuticular crests were found on males of both subspecies from wild boar and on females of O. ramachandrini.     

The New World filarial genus Molinema Freitas & Lent, 1939 (Nematoda: Onchocercidae), with a description of four new species parasitic in the Echimyidae (Rodentia)

Systematic Parasitology - Four new species of Molinema (Filarioidea: Onchocercidae), parasites of echimyid rodents in South America, are described: M. algardneri n. sp. from Proechimys...     

First account on the larval biology of a Litomosoides filaria,from a bat

Litomosoides filariae are parasites of unrelated groups of hosts, including bats, marsupials, ancient and modern rodents. The four life cycles to-date elucidated, develop in terrestrial mammals and, at least experimentally, in the mite Ornithonyssus bacoti. A batch of mites was fed on an infected bat, Artibeus jamaicensis captured in Costa Rica, and 18 days later one infective larva was recovered. Its morphology was similar to that of other Litomosoides species, with the characteristic long buccal capsule. These first accounts on the larval biology of Litomosoides from Microchiroptera confirm the unity of the genus which supports the view that it has passed from one group of hosts to another by means of captures.     

Successful immunotherapy with matrix metalloproteinase-derived peptides in adjuvant arthritis depends on the timing of peptide administration

We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.     

Litomosoides yutajensis n. sp., first record of this filarial genus in a mormoopid bat

Twenty-five bats were trapped in Yutaje (Amazonas, Venezuela) and examined for Litomosoides (Filarioidea: Onchocercidae). Of the nine recovered bat species, only Pteronotus parnelli was infected; it is a cave-dwelling species belonging to a family, Mormoopidae, which has not previously been included in the host range of the genus. The new species, L. yutajensis n. sp., has two median cephalic bosses covered with rugosities and differs from the 15 recognized species and subspecies from bats in several characters. Alike L. molossi Esslinger, 1973, L. chandleri Esslinger, 1973 and L. chitwoodi Bain, Guerrero, Rodriguez 2003, the new species has cuticular lateral bosses on the body. Eight of 10 P. parnelli were microfilaraemic, but only three had adult worms, showing that microfilariae survive longer than adults, which could lengthen the period of transmission. No infective larvae were detected in the following macronyssid mites: 58 Ornithonyssus bacoti, Ornithonyssinae, experimentally fed on microfilaraemic bats and dissected 15 days later, and a few Radfordiella sp., Macronyssinae, recovered from P. parnelli.     

Black flies (Diptera: Simuliidae) attracted to humans and water buffalos and natural infections with filarial larvae,probably Onchocerca sp., in northern Thailand

Several Simulium species were investigated as to their biting habits and natural infections with filarial larvae at Ban Pan Fan, Chiang Mai Province, in northern Thailand. Female adults flies landing on or flighting around a human and a water buffalo were collected during the daytime from 06.00 to 19.00 hours on 22 June 2001. As a result, 217 S. nodosum, 86 S. asakoae and two S. nigrogilvum were obtained from a human attractant, and 416 S. nodosum, 25 S. nakhonense, 16 S. asakoae, four S. fenestratum and two S. nigrogilvum, from a water buffalo. The blood-feeding was confirmed only for S. nodosum and S. nigrogilvum on humans, and for S. nodosum and S. nakhonense on water buffalos. Dissections of these simuliids showed that S. nodosum was naturally infected with developing filarial larvae. Two types of microfilariae were distinguished but only one type of infective larvae. These larvae resembled Onchocerca suzukii, a parasite from a wild Japanese bovid, suggesting that an unknown Onchocerca species from ruminants was transmitted in Thailand. Infection rates with all stages of larvae and third-stage larvae were 2.3% (14/608) and 1.0% (6/608), respectively. This is the first report of natural infections of black flies with Onchocerca larvae in Southeast Asia, and the involved black fly species is shown to be not only anthropophilic but also zoophilic in this region.     

Obligatory symbiotic Wolbachia endobacteria are absent from Loa loa

BACKGROUND: Many filarial nematodes harbour Wolbachia endobacteria. These endobacteria are transmitted vertically from one generation to the next. In several filarial species that have been studied to date they are obligatory symbionts of their hosts. Elimination of the endobacteria by antibiotics interrupts the embryogenesis and hence the production of microfilariae. The medical implication of this being that the use of doxycycline for the treatment of human onchocerciasis and bancroftian filariasis leads to elimination of the Wolbachia and hence sterilisation of the female worms. Wolbachia play a role in the immunopathology of patients and may contribute to side effects seen after antifilarial chemotherapy. In several studies Wolbachia were not observed in Loa loa. Since these results have been doubted, and because of the medical significance, several independent methods were applied to search for Wolbachia in L. loa. METHODS: Loa loa and Onchocerca volvulus were studied by electron microscopy, histology with silver staining, and immunohistology using antibodies against WSP, Wolbachia aspartate aminotransferase, and heat shock protein 60. The results achieved with L. loa and O. volvulus were compared. Searching for Wolbachia, genes were amplified by PCR coding for the bacterial 16S rDNA, the FTSZ cell division protein, and WSP. RESULTS: No Wolbachia endobacteria were discovered by immunohistology in 13 male and 14 female L. loa worms and in numerous L. loa microfilariae. In contrast, endobacteria were found in large numbers in O. volvulus and 14 other filaria species. No intracellular bacteria were seen in electron micrographs of oocytes and young morulae of L. loa in contrast to O. volvulus. In agreement with these results, Wolbachia DNA was not detected by PCR in three male and six female L. loa worms and in two microfilariae samples of L. loa. CONCLUSIONS: Loa loa do not harbour obligatory symbiotic Wolbachia endobacteria in essential numbers to enable their efficient vertical transmission or to play a role in production of microfilariae. Exclusively, the filariae cause the immunopathology of loiasis is patients and the adverse side effects after antifilarial chemotherapy. Doxycycline cannot be used to cure loiais but it probably does not represent a risk for L. loa patients when administered to patients with co-infections of onchocerciasis.     

Litomosoides sigmodontis in mice: reappraisal of an old model for filarial research

Onchocerciasis and lymphatic filariasis (LF) are major causes of severe morbidity and considerable socio-economic problems throughout the tropics. Vector control and mass chemotherapy have helped to control these infections in some regions, but the temporary success of such measures argues strongly for the development of vaccines. Success in such a venture will require detailed knowledge of protective immune responses in conjunction with the identification of target antigens. By comparison with other important parasitic infections, such as schistosomiasis and leishmaniasis, work on the development of vaccines for onchocerciasis and LF has been constrained because of the difficulties of producing cyclical and patent filarial infection in laboratory mice. Wolfgang Hoffmann and colleagues here outline the opportunities presented by the rodent filaria Litomosoides sigmodontis for filarial research.     

Retro-recombination screening of a mouse embryonic stem cell genomic library

Targeted gene disruption is an important tool in molecular medicine, allowing for the generation of animal models of human disease. Conventional methods of targeting vector (TV) construction are difficult and represent a rate limiting step in any targeting experiment. We previously demonstrated that bacteriophage are capable of acting as TVs directly, obviating the requirement for ‘rolling out’ plasmids from primary phage clones and thus eliminating an additional, time consuming step. We have also developed methods which facilitate the construction of TVs using recombination. In this approach, modification cassettes and point mutations are shuttled to specific sites in phage TVs using phage–plasmid recombination. Here, we report a further improvement in TV generation using a recombination screening-based approach deemed ‘retro-recombination screening’ (RRS). We demonstrate that phage vectors containing specific genomic clones can be genetically isolated from a λTK embryonic stem cell genomic library using a cycle of integrative recombination and condensation. By introducing the gam gene of bacteriophage λ into the probe plasmid it is possible to select for positive clones which have excised the plasmid, thus returning to their native conformation following purification from the library. Rapid clone isolation using the RRS protocol provides another method by which the time required for TV construction may be further reduced.     

A phylogeny of Packera (Senecioneae; asteraceae) based on internal transcribed spacer region sequence data and a broad sampling of outgroups

A phylogeny of Packera is presented based on sequence data from the internal transcribed spacer region of nuclear ribosomal DNA of 26 species (28 populations) of Packera and 23 outgroup taxa, including representatives of all three subtribes of the Senecioneae. The results support a Mexican origin for Packera, with its closest relatives found among Old World taxa in the subtribe Senecioninae, such as Senecio jacobaea and Pericallis. Packera species from the west coast of the United States, previously included in the section Bolanderi of Greenman, are part of a basal assemblage including species of Greenman's Mexican section Sanguisorboidei. The rest of Packera separates into two sister groups, one containing species from the Arizona-New Mexico region and the other containing more geographically diverse taxa. Among the outgroups, New World Senecio species are monophyletic and two Tussilaginoid assemblages are strongly supported; the Tephroseroid group (Tephroseris and Sinosenecio) plus Petasites combine with the Luina complex to form a clade of north temperate taxa, and the four Mexican genera (Psacalium, Robinsonecio, Barkleyanthus, and Pittocaulon) form a monophyletic group.