Three recent studies of Blastocystis epidemiology in mammalian hosts identified four novel sequences that appeared to share B. lapemi as the most similar sequence. However, full-length ssu rRNA gene sequences were not available to confirm the validity of these new subtypes. In the present study, Nanopore MinION sequencing was used to obtain full-length reference sequences for each of the new subtypes. Additionally, phylogenetic analyses and pairwise distance comparisons were performed to confirm the validity of each of these new subtypes. We propose that the novel sequences described in this study should be assigned the subtype designations ST35-ST38. The full-length reference sequences of ST35-ST38 will assist in accurate sequence descriptions in future studies of Blastocystis epidemiology and subtype diversity.

The triatomines vectors of Trypanosoma cruzi are principal factors in acquiring Chagas disease. For this reason, increased knowledge of domestic transmission of T. cruzi and control of its insect vectors is necessary. To contribute to genetic knowledge of North America Triatominae species, we studied genetic variations and conducted phylogenetic analysis of different triatomines species of epidemiologic importance. Our analysis showed high genetic variations between different geographic populations of Triatoma mexicana, Meccus longipennis, M. mazzottii, M. picturatus, and T. dimidiata species, suggested initial divergence, hybridation, or classifications problems. In contrast, T. gerstaeckeri, T. bolivari, and M. pallidipennis populations showed few genetics variations. Analysis using cytochrome B and internal transcribed spacer 2 gene sequences indicated that T. bolivari is closely related to the Rubrofasciata complex and not to T. dimidiata. Triatoma brailovskyi and T. gerstaeckeri showed a close relationship with Dimidiata and Phyllosoma complexes.

Theory predicts that parasites can affect and thus drive their hosts’ niche. Testing this prediction is key, especially for vector-borne diseases including Chagas disease. Here, we examined the niche use of seven triatomine species that occur in Mexico, based on whether they are infected or not with Trypanosoma cruzi, the vectors and causative parasites of Chagas disease, respectively. Presence data for seven species of triatomines (Triatoma barberi, T. dimidiata, T. longipennis, T. mazzottii, T. pallidipennis, T. phyllosoma and T. picturata) were used and divided into populations infected and not infected by T. cruzi. Species distribution models were generated with Maxent 3.3.3k. Using distribution models, niche analysis tests of amplitude and distance to centroids were carried out for infected vs non-infected populations within species. Infected populations of bugs of six out of the seven triatomine species showed a reduced ecological space compared to non-infected populations. In all but one case (T. pallidipennis), the niche used by infected populations was close to the niche centroid of its insect host. Trypanosoma cruzi may have selected for a restricted niche amplitude in triatomines, although we are unaware of the underlying reasons. Possibly the fact that T. cruzi infection bears a fitness cost for triatomines is what narrows the niche breadth of the insects. Our results imply that Chagas control programmes should consider whether bugs are infected in models of triatomine distribution.

A large variety of mammals act as natural reservoirs of Trypanosoma cruzi (the causal agent of Chagas disease) across the American continent. Related issues are infection and parasite burden in these reservoirs, and whether they are able to control T. cruzi infections. These parameters can indicate the real role of mammals as T. cruzi reservoirs and transmitters. Here, two species of mammals, white-nosed coati (Nasua narica) and raccoon (Procyon lotor), were examined for to determine: a) T. cruzi presence, and; b) their ability to control T. cruzi infection. Multiple capture-recaptures of both species were carried out in semi-wild conditions in Villahermosa, Tabasco, Mexico, for 5 years. Two samplings per year (summer and winter) took place. Prevalence and pattern of T. cruzi infection were determined by PCR from both mammals’ blood samples. Raccoon samples had a higher relative infection values (26.6%) compared to those of white-nosed coati (9.05%), being this difference significant in summer 2012 (P < 0.00001), summer (P = 0.03) and winter 2013 (P = 0.02). Capture and recapture data indicated three infection dynamics: 1) negative–positive-negative infection; 2) positive–negative-positive infection; and 3) positive at all sampling times. These results indicate that both coati and raccoons may be able to control T. cruzi infection. Thus, the role as efficient reservoirs could be questioned (at least for those times when mammals are able to tolerate the infection). However, while infected, they may also be able to approach human dwellings and play a role important in linking sylvatic and domestic cycles.

Background: Chagas disease (CD) is caused by the protozoan parasite Trypanosoma cruzi and is transmitted by triatomine insects. Clinical manifestations vary according to the phase of the disease. Cutaneous manifestations are usually observed in the acute phase (chagoma and Romaña’s sign) or after reactivation of the chronic phase by immunosuppression; however, a disseminated infection in the acute phase without immunosuppression has not been reported for CD. Here, we report an unusual case of disseminated cutaneous infection during the acute phase of CD in a Mexican woman. Methods: Evaluation of the patient included a complete clinical history, a physical exam, and an exhaustive evaluation by laboratory tests, including ELISA, Western blot and PCR. Results: Skin biopsies of a 50-year-old female revealed intracellular parasites affecting the lower extremities with lymphangitic spread in both legs. The PCR tests evaluated biopsy samples obtained from the lesions and blood samples, which showed a positive diagnosis for T. cruzi. Partial sequencing of the small subunit ribosomal DNA correlated with the genetic variant DTU II; however, serological tests were negative. Conclusions: We present a case of CD with disseminated skin lesions that was detected by PCR and showed negative serological results. In Mexico, an endemic CD area, there are no records of this type of manifestation, which demonstrates the ability of the parasite to initiate and maintain infections in atypical tissues.