This study aimed to document the geographic distribution of Ixodes tick species in dogs and the prevalence of Borrelia burgdorferi s.l. in adult ticks and blood samples by amplification of the ospA region of the B. burgdorferi genome. The study area included nine localities in Nuevo León state. DNA amplification was performed on pools of ticks to calculate the maximum likelihood estimation (MLE), and the community composition (prevalence, abundance, and intensity of infestation) was recorded. A total of 2,543 adult ticks, representing four species, Rhipicephalus sanguineus, Dermacentor variabilis, Rhipicephalus (Boophilus) annulatus, and Amblyomma cajennense, were recorded from 338 infested dogs. Statistically significant correlations were observed between female dogs and infestation (P = 0.0003) and between R. sanguineus and locality (P = 0.0001). Dogs sampled in Guadalupe and Estanzuela were positive by PCR (0.9 %) for B. burgdorferi. Rhipicephalus sanguineus had the highest abundance, intensity, and prevalence (10.57, 7.12 and 94.6, respectively). PCR results from 256 pools showed that four pools were positive for D. variabilis (1.6 %), with an MLE of 9.2 %; nevertheless, it is important to consider that in the area under examination probably other reservoir hosts for D. variabilis and B. burgdorferi are present that, very likely, play a much more important role in the ecology of Lyme borreliosis than dogs, which could be considered in future studies.
Activity against Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) of methanolic extracts of medicinal use plants in Mexico. American trypanosomiasis is a potentially lethal disease caused by the hemoflagellate protozoan Trypanosoma cruzi. This neglected disease affects from 6 to 7 million people worldwide. Currently there are only two medicines to treat this disease: beznidazol and nifurtimox, both effective if they are administrated in the acute phase of infection, although their effectiveness fades away in the chronic phase; it also induces significant side effects. The aim of this study is to screen the trypanocidal activity of methanolic extracts from Hematoxilum brasiletto, Marrubium vulgare, Schinus molle, and Cympongon citratus, against T. cruzi epimastigotes, followed by the chromatographic separation, and identification of active compounds of the best candidate by colored chemical reactions; furthermore, it was also determined their cytotoxic effect in human lymphocytes and the brine shrimp Artemia salina. The extract of H. brasiletto showed the highest anti-T. cruzi activity with a inhibitory concentration (IC 50 ) of 543 µg/mL; in descending order, it was followed by M. vulgare (IC 50 = 647 µg/mL), S. molle (IC = 827 µg/mL) and finally, C. citratus (IC = 1 210 µg/mL). The chromatographic fraction Fr22 from H. brasiletto showed the best anti-T. cruzi effectivity (IC 50 = 0.238 mg/mL), when compared to the other fraction or the whole extract, with no cytotoxic effect against human lymphocytes or A. salina. The active compounds were identified as tannins, quinones, flavonoids and sesquiterpenlactones. In conclusion, active compounds against T. cruzi were identified for the first time in H. brasiletto, with non-cytotoxic effects. The H. brasiletto extract, according to our results, could be used as an alternative treatment for the Chagas disease; however, additional studies will be necessary to test their activity and doses in a murine model, with the complete identification of the active compounds, on which we are investigating. Rev. Biol. Trop. 65 (4) La tripanosomiasis americana es una enfermedad potencialmente mortal causada por el protozoario Trypanosoma cruzi (Chagas, 1909). Las zonas endémicas abarcan 21 países de América Latina, donde el parásito se transmite principalmente por vía vectorial (Calvo, 2015). La enfermedad presenta dos fases; el inicio de la infección es la fase aguda, y permanece hasta dos meses con parasitemia, fiebre y malestar. La etapa crónica, que se desarrolla después de algunos años en el 25-35 % de las personas infectadas, se caracteriza por no presentar parasitemia; en esta fase, los parásitos se alojan y reproducen en nidos de amastigotes de órganos y sistema nervioso periférico, de los cuales un 30 % desarrolla desórdenes cardíacos y un 10 %, trastornos nerviosos y digestivos como el megacolon o megaesófago (Martino, 2012). Actualmente, los movimientos migratorios la han diseminado desde las regiones endé-micas hasta Canadá y varios países europeos (Slot, Ho...
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