Morphological and molecular characteristics of a Trypanosoma sp. from breeding Triatomines (Triatoma rubrofasciata) in China

Abstract

Abstract Background Triatomines (kissing bugs) are natural trypanosome vectors that transmit trypanosome species, including Trypanosoma cruzi, Trypanosoma conorhini and Trypanosoma rangeli. Here we reported the first solid record of Trypansoma conorhini from Triatomia rubrofaciata in China. Methods The intestinal contents of the Triatomine rubrofasciata were collected to prepare smears and examined by microscopy. The morphological indices of trypanosome species were measured and calculated. The genomic DNA fragment of trypanosomes was extracted, and the genes of 18S rRNA gene, HSP70 and glycosomal glyceraldehyde-3-phosphate dehydrogenase genes (gGAPDH) were PCR amplified and sequenced. The obtained sequences were subjected to a BLAST search in NCBI and followed by phylogenetic analysis with other homologous trypanosomes. To investigate the prevalence of this trypanosome, 135 T. rubrofasciata samples from different regions of Guangxi were collected and assayed. Moreover, laboratory infection was conducted to test the possible transmission between Tr. rubrofasciata and rats (or mice) though Tr. Rubrofasciata bite. Results The parasite found in the intestinal contents of Tr. rubrofaciata, which were collected in the Guangxi region of southern China, exhibits the typical characteristics of epimastigotes, such as the presence of a nucleus, a free flagellum and a kinetoplast. The body length ranged from 6.3–33.9 µm, and flagellum length ranged from 8.7–29.8 µm; the nucleus index was 0.6, and the kinetoplast index was − 4.6. The BLAST analysis showed that the 18S rRNA, HSP70, and gGAPDH sequences of the Trypanosoma sp. exhibit the highest degree of similarity with T. conorhini (99.7%, 99.0%, 99.0%), and formed a well-supported clade close to T. conorhini and T. vespertilionis, while exhibiting a significant distance from T. rangeli and T. cruzi. Our investigation uncovered a high prevalence of Trypanosoma sp. infection in Tr. rubrofaciata up to 36.3% in the field. The laboratory experiments showed that both rats and mice could get Trypansoma sp. infected through bites from wild Tr. rubrofaciata, and lab-feeding Tr. rubrofaciat can get Trypansoma sp. infected through bloodmeals of infected mice. Conclusion Trypanosoma conorhini was found in Tr. rubrofasciata in China, as judged by morphology and molecular markers. This parasite had a high prevalence in T. rubrofasciata, and lab experiment showed Trypanosoma conorhini in China could be transmitted between Tr. rubrofasciata and rat(mice) through Tr. rubrofasciata bites; whether this parasite is pathogenic to human need to be future research.