Differentiation of Trichuris species using a morphometric approach.

Trichuris trichiura is a nematode considered as the whipworm present in humans and primates. The systematics of the genus Trichuris is complex. Morphological studies of Trichuris isolated from primates and humans conclude that the species infecting these hosts is the same. Furthermore, numerous molecular studies have been carried out so far to discriminate parasite species from humans and Non-Human Primates using molecular techniques, but these studies were not performed in combination with a parallel morphological study. The hypothesised existence of more species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other putative new species of whipworms. In the present work, a study of Trichuris Roederer, 1761 (Nematoda:Trichuridae) parasitizing C. g. kikuyensis, P. ursinus, Macaca sylvanus, Pan troglodytes, and Sus scrofa domestica has been carried out using modern morphometric techniques in order to differentiate populations of Trichuris isolated from four species of captive NHP from different geographical regions, and swine, respectively. The results obtained revealed strong support for geometrical morphometrics as a useful tool to differentiate male Trichuris populations. Therefore, morphometrics in combination with other techniques, such as molecular biology analyses, ought to be applied to further the differentiation of male populations. On the other hand, morphometrics applied to female Trichuris species does not seem to contribute new information as all the measurements combinations of obtained from females always showed similar results.

Origin, evolution, phylogeny and taxonomy of Pulex irritans.

The human flea Pulex irritans Linnaeus, 1758 (Siphonaptera: Pulicidae) is one of the most studied species together with the cat flea Ctenocephalides felis Bouché, 1835, because they have a cosmopolitan distribution and are closely related to humans. The present study aimed to carry out a comparative morphometric and molecular study of two different populations of P. irritans (Spain and Argentina). Accordingly, internal transcribed spacer (ITS)1 and ITS2 of rDNA and the partial cytochrome c oxidase subunit 1 (cox1) and cytochrome b (cytb) mtDNA genes of these taxa were sequenced. Furthermore, the taxonomy, origin, evolution and phylogeny of P. irritans was assessed. The morphometric data obtained did not show significant differences between P. irritans specimens from Spain and Argentina, even when these two populations were collected from different hosts; however, there was a considerable degree of molecular divergence between both populations based on nuclear and mitochondrial markers. Thus, it is proposed that P. irritans, in contrast with other generalist fleas, maintains a certain degree of morphological similarity, at least between Western Palearctic and Neotropical areas. Furthermore, two well defined geographical genetic lineages within the P. irritans species are indicated, suggesting the existence of two cryptic species that could be discriminated by a polymerase chain reaction-linked restriction fragment length polymorphism.

[Role of rituximab in the management of refractory autoimmune cytopenia]. / Rituximab en el tratamiento de citopenias autoinmunitarias refractarias a tratamientos convencionales.

OBJECTIVES: This study examined the efficacy of rituximab in children with refractory autoimmune cytopenia. MATERIAL AND METHODS: Longitudinal descriptive study comprising a series of clinical cases (n=7) during the period 2003 to 2010. RESULTS: A series 7 patients were included (4 had primary immune thrombocytopenia, 2 autoimmune hemolytic anemia, and 1 autoimmune neutropenia). One patient had received stem cell transplantation. Rituximab was administered intravenously to all patients at a dose of 375 mg/mg(2) weekly. Four patients received 4 doses. Three patients received 2, 6, and 8 doses, respectively. Overall, 5 patients responded (4 complete responses plus 1 partial response). The median time to achieve complete response was 8.5 weeks (range: 3.5-19.5 weeks). Two patients achieved complete response in the first 3.5 weeks, and the remaining 3 patients between 8.5 and 19.5 weeks. The median time of response was 35.5 weeks (range: 12.5-53.5 weeks). Two patients relapsed. No serious adverse events were recorded. CONCLUSIONS: Overall, seventy one percent of patients in this study respond to treatment, 100% of responders decrease their previous treatment. Rituximab was a well tolerated and no related serious side effects were recorded during the study period.