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

Abstract

Background

Triatomines (kissing bugs) are natural vectors of trypanosomes, which are single-celled parasitic protozoans, such as Trypanosoma cruzi, Tconorhini and Trangeli. The understanding of the transmission cycle of Tconorhini and Triatoma rubrofasciata in China is not fully known.

Methods

The parasites in the faeces and intestinal contents of the Tr. rubrofasciata were collected, and morphology indices were measured under a microscope to determine the species. DNA was extracted from the samples, and fragments of 18S rRNA, heat shock protein 70 (HSP70) and glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) were amplified and sequenced. The obtained sequences were then identified using the BLAST search engine, followed by several phylogenetic analyses. Finally, laboratory infections were conducted to test whether Trrubrofasciata transmit the parasite to rats (or mice) through bites. Moreover, 135 Trrubrofasciata samples were collected from the Guangxi region and were used in assays to investigate the prevalence of trypanosome infection.

Results

Trypanosoma sp. were found in the faeces and intestinal contents of Tr. rubrofasciata, which were collected in the Guangxi region of southern China and mostly exhibited characteristics typical of epimastigotes, such as the presence of a nucleus, a free flagellum and a kinetoplast. The body length ranged from 6.3 to 33.9 µm, the flagellum length ranged from 8.7 to 29.8 µm, the nucleus index was 0.6 and the kinetoplast length was −4.6. BLAST analysis revealed that the 18S rRNA, HSP70 and gGAPDH sequences of Trypanosoma sp. exhibited the highest degree of similarity with those of Tconorhini (99.7%, 99.0% and 99.0%, respectively) and formed a well-supported clade close to Tconorhini and Tvespertilionis but were distinct from those of Trangeli and Tcruzi. Laboratory experiments revealed that both rats and mice developed low parasitaemia after inoculation with Trypanosoma sp. and laboratory-fed Trrubrofasciata became infected after feeding on trypanosome-positive rats and mice. However, the infected Trrubrofasciata did not transmit Trypanosoma sp. to their offspring. Moreover, our investigation revealed a high prevalence of Trypanosoma sp. infection in Trrubrofasciata, with up to 36.3% of specimens tested in the field being infected.

Conclusions

Our study is the first to provide a solid record of Tconorhini from Trrubrofasciata in China with morphological and molecular evidence. This Chinese Tconorhini is unlikely to have spread through transovarial transmission in Trrubrofasciata, but instead, it is more likely that the parasite is transmitted between Trrubrofasciata and mice (or rats). However, there was a high prevalence of Tconorhini in the Trrubrofasciata from our collection sites and numerous human cases of Trrubrofasciata bites were recorded. Moreover, whether these Tconorhini strains are pathogenic to humans has not been investigated.

Graphical Abstract

Background

The Trypanosoma genus comprises single-celled protozoan parasites. They are composed of seven subgenera, three of which are stercorarians and four of which are salivarians [1, 2]. These parasites are widespread globally and can infect both humans and diverse animal species [3]. They are blood-borne parasites and can be transmitted by haematophagous vectors, such as leeches, biting flies and kissing bugs [4]. These parasites cause diseases that are both economically and socially significant, such as sleeping sickness in equatorial Africa and Chagas disease in Latin America [5]. Trypanosoma brucei is transmitted by tsetse flies and causes sleeping sickness. There are two forms of this disease: a chronic form caused by Tbgambiense infection in West and Central Africa and an acute form caused by Tbrhodesiense in East Africa [6, 7]. Similarly, Tcruzi is mostly transmitted by insects in the subfamily Triatominae and causes Chagas disease, which is a significant human disease causing approximately 6 million infections in the Americas [8]. Chagas disease can lead to both high morbidity and mortality rates among adults in endemic countries, leading to more than 10,000 deaths annually [8].

Triatominae insects, commonly called “kissing bugs”, may spread many medically important microorganisms and viruses, especially pathogens, such as Tcruzi, which may threaten public health [9]. In addition to harbouring Tcruzi infection, triatomines can carry many Trypanosoma species, such as Trangeli and Tconorhini. The two latter species have not been associated with symptomatic human pathologies or diseases [10]. However, nonhuman primates are commonly infected with these parasites, and the geographical distribution of Trangeli often overlaps with that of Tcruzi, as they often share the same vertebrate and invertebrate hosts. This overlap between nonmedically and medically important species could lead to incorrect diagnosis of Tcruzi infections on the basis of morphological examination [11]. Trypanosoma conorhini was reported to have a mysterious host range in rats, mice and nonhuman primates [12, 13]. In many Asian countries, Trrubrofasciata has been reported to be infected with Tconorhini [14, 15], with countries, such as Vietnam, having reports of coinfections with both Tconorhini and Tlewisi [15]. However, the current data available about the distribution of Trypanosoma species in Asia have mostly been based on morphological identification methods. Therefore, there is currently insufficient molecular evidence that Trrubrofasciata carries Tconorhini in China.

In Asia, there are currently seven species of Triatoma, of which only two species (Trrubrofasciata and Trsinica) are commonly found in China [16]. The presence of Trrubrofasciata in southern China has recently drawn the attention of the public because it tends to bite humans [17, 18]. In 2023, two new Triatoma species (Trpicta and Tratrata) were recognized [19]. Previous studies revealed that Trrubrofasciata is widely distributed in southern China (e.g. in Guangdong Province, Hainan Province and the Guangxi Zhuang Autonomous Region), where people are reportedly bitten [20, 21]. In this study, flagellates were found in field-captured Trrubrofasciata. We were therefore interested in documenting the prevalence of Trypanosoma infections in South China populations; Trrubrofasciata was used to investigate the morphological and molecular characteristics of these trypanosomes and to analyse which animal species they can infect.

Methods

Triatomine sample collection for parasite identification

Triatomines were collected from piles of wood in Chongzuo City and Beihai City from June to November 2021–2022 in the Guangxi Zhuang Autonomous Region, including Jiangzhou district (22.40520083N, 107.35192533E) and Hepu County (21.8213004237N, 109.4140264191E). The samples were transferred to the laboratory for feeding. The species of the collected triatomines were identified using both morphological and molecular biology methods as previously described [18, 21].

Parasite morphology identification

Trypanosomes were observed in triatomines by diluting the faeces and intestinal contents with phosphate-buffered saline (PBS), smearing the solution onto a microscope slide and observing the slides under a microscope. Moreover, the same sample smearing after Giemsa staining were observed. Similarly, trypanosomes in rat/mouse blood samples treated with PBS and Giemsa stain were observed under a microscope. Identification was performed on the basis of the parasites’ morphological features as described by Hoare [3]. Briefly, after taking the photo, centre-to-centre distances were measured using ImageJ v1.54 [22], i.e. from the posterior end to the nucleus (PN), from the posterior end to the kinetoplast (PK), from the kinetoplast to the nucleus (KN) and from the anterior end to the nucleus (NA); body length (BL), not counting the free flagellum, i.e. posterior end to the anterior end; free flagellum length (FF); total length (TL), i.e. BL + FF; cell maximum body width (BW); nucleus width (NW); and nucleus length (NL). The indices representing the position of the nucleus (NI = PN/NA), kinetoplast (KI = PN/KN) and flagellum (FI = FF/BL) were also calculated.

Parasite molecular identification

DNA extraction and polymerase chain reaction

Using the QIAamp DNA Mini Kit (Qiagen, Germany), DNA from 200 µl of gut content from each triatomine was extracted according to the manufacturer’s recommendations. The 18S rRNA, heat shock protein 70 (HSP70), glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) and internal transcribed spacer region (ITS) gene sequences were amplified via PCR (the primer information for each gene is listed in Table 1). The reactions were conducted in a final volume of 25 μl, consisting of 30 ng of DNA template, 1 × Taq PCR Master Mix (Takara, China), and 0.4 μM of each primer. The fragments were amplified with the following thermal cycling conditions: 95 °C for 3 min; 35 cycles of 94 °C for 30 s, 48–58 °C for 60 s, and 72 °C for 90 s; and 72 °C for 10 min.

Table 1 The primer information

The amplicons were purified using the MiniBEST Agarose Gel DNA Extraction Kit (Takara, Dalian, China) according to the manufacturer’s recommendations and subsequently conjugated with the PMD20-T vector (Takara, Dalian, China). Two positive clones were sent to Sangon Biotech (Shanghai, China) for sequencing of both strands. The sequencing reactions were performed using the ABI Prism® BigDye® Terminator v3.1 Cycle Sequencing Kit (Applied Biosystems) with RimersM13 in an ABI 3730 sequencer.

Molecular analysis and phylogenetic analysis

The obtained 18S rRNA, HSP70, gGAPDH and ITS sequences were compared with those available in the GenBank database (NCBI) by the Basic Local Alignment Search Tool (BLAST) (http://blast.ncbi.nlm.nih.gov/Blast.cgi) to identify the homologous sequences and download sequences from different trypanosome species. Multiple sequence alignments of homologous trypanosomes, such as Tconorhini, Tvespertilionis, Tcruzi, T. rangeli, T. wauwu, Tdionisii, Terneyi and Tlivingstonei from different hosts or geographic origins were downloaded from NCBI (for sequence information, see Additional file 1: Table S1) and aligned using ClustalW (https://www.genome.jp/tools-bin/clustalw). Maximum-likelihood and neighbour-joining models were used to construct analysis trees on the basis of the 18S rRNA, HSP70 and gGAPDH genes via MEGA 11, and bootstrap support with 1000 replicates was performed [23]. In addition, MEGA 11 was used to calculate the divergence time of the isolated Trypanosoma sp. from Tcruzi and Tbrucei using the 18S rRNA sequences [23].

Infection experiment

To identify whether Trrubrofasciata could transmit trypanosomes, fresh triatomine faeces were mixed with one drop of PBS to detect trypanosomes directly via microscopy. Next, Kunming mice, C57BL/6J, BALB/cA-nu and Sprague‒Dawley rats were infected with these trypanosomes by intraperitoneal injection of the faeces. Blood samples were taken from the tails of the rats and mice every 12 h post infection to detect trypanosomes. Then, the infected mice and rats were bitten, and blood was collected from the laboratory-bred, uninfected Trrubrofasciata. After feeding, the fresh faecal matter of these bugs was checked to detect trypanosome infection using the method described above.

Transovarian transmission experiment

In total, six infected female Trrubrofasciata were used in this study. The laid eggs were collected in a container for hatching, and the first-stage nymphs were fed the Kunming mouse blood throughout their nymph life cycle and into the adult stage. The suspension drop method was used to detect trypanosomes in fresh faeces twice a week as described above.

Investigation of natural Trypanosoma sp. infection

To investigate the prevalence of trypanosomes in wild Trrubrofasciata populations, 135 triatomines, including 61 adults and 74 nymphs were collected. DNA was extracted from the abdominal tissues of the Trrubrofasciata, and a nested PCR strategy for detecting and identifying Trypanosoma species as previously described by Noyes et al. was used [24]. The PCR primer information is listed in Table 1, and the PCR amplification conditions were as follows: 94 °C for 3 min; 30 cycles of 94 °C for 30 s, 55 °C for 60 s, and 72 °C for 90 s; and 72 °C for 10 min. In addition, 16 Rattus norvegicus were collected near the triatomine collection sites in Chongzuo City. Blood samples were collected from the tail, and the blood was examined via trypanosomes. DNA was also extracted from the blood samples, and the DNA was amplified using the nested PCR method as described above to detect trypanosome infection [24]. All the positive PCR products were sequenced and subjected to BLAST to identify the Trypanosoma species.

Results

Triatomine specimen identification

All the triatomines were identified morphologically as Trrubrofasciata. The 16S rRNA and cytb PCR results of Trubrofasciata, which yielded 499 bp and 667 bp fragments, respectively, were all identical and 100% matched those of the Trrubrofasciata in GenBank (accession nos. MH236905 and MH368021). The species was identified molecularly as Trrubrofasciata.

Microscopic observations

Flagellates were found in the faeces of the Trrubrofasciata. They were observed to have characteristics of Trypanosoma species and were motile (Additional file 1: Video S1). The faeces and intestinal contents were stained with Giemsa, and the results showed that the parasites mostly appeared as classical epimastigotes (Fig. 1a–d), but there were also a few promastigotes (Fig. 1e). According to morphology, the epimastigotes can be divided into three primary forms: the first is a slender epimastigote with a fine posterior end (Fig. 1a), the second is a stumpy epimastigote with a finger shape or fine posterior end (Fig. 1b, c) and the third is a rare epimastigote with a round posterior end (Fig. 1d).

Fig. 1
figure 1

The morphology of Trypanosoma sp. in Triatoma rubrofasciata. a slender epimastigote form; b and c stumpy epimastigote form; d epimastigote form with round posterior end; e promastigote form

The nucleus, undulating membrane, flagellum and kinetoplast were apparent. The nucleus and the kinetoplast were close, with the former oval and anterior and the latter appearing as a dense dot far from the posterior extremity. The body length of the observed epimastigotes ranged from 6.3 to 33.9 µm, and the length of the free flagellum ranged from 2.3 to 19.0 µm (Table 2). After Giemsa staining, mice and rats infected in the laboratory were found to have typical trypomastigotes with well-developed undulating membrane bodies and clear flagellar pockets. The body length of the trypomastigotes was 36.7–52.5 µm, and the free flagellum length ranged from 4.8–10.5 µm (Fig. 2a, Table 2).

Table 2 Morphometrics of isolated trypanosomes compared with Tconorhini
Fig. 2
figure 2

Morphological comparison of the Trypanosoma sp. (from rat and Trrubrofasciata) with Tconorhini in literature. a Trypanosoma sp. In lab infected rat; bd Principal component analysis on morphological data (Table 2; TL: total cell length; BW: body width; NL, nucleus length; NW: nucleus width; NI: nucleus index, equals to PN/NA; KI: kinetoplast index, equal to PN/KN; and FI: flagellar index, equal to FF/BL) of our isolated trypanosomes with literature data. Grouping by cell forms (b) or by living temperature (c). The loading of parameters were indicated in blue (d). # data from T. conorhini drawings (Deane and Deane 13)

A comparison of the morphological characteristics of the isolated trypanosomes and Tconorhini from literature [13] is shown in Table 2 and Fig. 2b–d based on measurements of the distance and the index below. As expected, the morphological data were split into two major groups with regard to the kinetoplast index (KI, equal to PN/KN), trypomastigotes and the rest (epimastigotes and promastigotes). The distribution of these two major groups, which stretched nearly horizontally into stratiform regions, was attributed to the total length of the cell (TL, equal to BL plus FF) and the flagellar index (FI, equal to FF/BL). A comparison of these data for the isolated Trypanosoma sp. with specific Tconorhini data from the literature strongly suggested a close relationship.

Phylogenies based on the 18S rRNA, gGAPDH and HSP70 sequences

After cloning and sequencing, we obtained 2018 bp, 922 bp and 769 bp fragments of the 18S rRNA, gGAPDH (accession no. MZ043866) and HSP70 (accession no. MZ043865) sequences, respectively. BLAST analysis revealed that the closest 18S rRNA sequence was most similar (99.7%) to that of the Tconorhini strain Tco025E (accession no. MKKU01000460), which was isolated from Rrattus in Brazil. BLAST analysis of gGAPDH fit with Tconorhini Tco025E_10018 (99.0%, accession no. XM_029376810). HSP70 fit with Tconorhini Tco025E_09744 (99.0%, accession no. XM_029376553), which was isolated from Rrattus in Brazil, and TCC2156 (accession no. MF144909), which was isolated from Trrubrofasciata in the USA.

The obtained 18S rRNA, HSP70 and gGAPDH sequences were subjected to phylogenetic tree construction with representative species of all major trypanosome clades (Figs. 3, 4, 5). The new triatomine trypanosomes formed a well-supported clade close to Tconorhini and Tvespertilionis in all phylogenetic trees. According to the 18S rRNA phylogenetic trees, the newly isolated cluster contained four Tconorhini isolates from the Trrubrofasciata and rats: TCC1452, TCC2156, USP and Tco025E; and three Tverspertilionis isolates from bats and bugs: G1, G2, and P14. The newly isolated cluster was distinct from those of Trangeli and Tcruzi (Fig. 3). In the gGAPDH and HSP70 phylogenetic trees, the newly isolated clade with two isolates of Tconorhini (TCC1452 and TCC2156) was found to be closer to the Trypanosoma sp. Hoch-like G3 and HochNdil (from bats and monkeys) and Tvespertilionis G1, G2, EU and P14 clades than to the Trangeli and Tcruzi clades (Figs. 4, 5).

Fig. 3
figure 3

The phylogenetic tree is based on the 18S rRNA gene sequences from newly isolated Trypanosoma sp. and other related species. The phylogenetic tree was constructed by MEGA using the neighbour-joining (NJ) method with 1000 bootstrap replications. The accession numbers of 18S rRNA sequences of Trypanosoma spp. in GenBank are in Additional file 1: Table S1. The phylogenetic analysis showed the isolated Trypanosoma sp. is close with Tconorhini

Fig. 4
figure 4

The phylogenetic tree is based on the heat shock protein 70 sequences from newly isolated Trypanosoma sp. and other related species. The phylogenetic tree was constructed by MEGA using the neighbour-joining (NJ) method with 1000 bootstrap replications. The accession numbers of gGAPDH sequences of Trypanosoma spp. in GenBank are in Additional file 1: Table S1. The phylogenetic analysis showed the isolated Trypanosoma sp. is close with Tconorhini

Fig. 5
figure 5

The phylogenetic tree is based on the glycosomal glyceraldehyde-3-phosphate dehydrogenase sequences from newly isolated Trypanosoma sp. and other related species. The phylogenetic tree was constructed by MEGA using the neighbour-joining (NJ) method with 1000 bootstrap replications. The accession numbers of HSP70 sequences of Trypanosoma spp. in GenBank are in Additional file 1: Table S1. The phylogenetic analysis showed the isolated Trypanosoma sp. is close with Tconorhini

Additional sequencing of ITS1 (652 bp) from the isolated trypanosomes revealed 98.8% similarity to the Tconorhini reference strain Tco025E (accession no. MKKU01000460). Overall, this newly isolated trypanosome genome is the first published record of a Chinese Tconorhini. By applying a possible divergence time of 100 million years ago (MYA) between Tcruzi and Tbrucei brucei [25], we estimated a possible divergence time of 1 Ma between Chinese Tconorhini and the South American strains (Fig. 6).

Fig. 6
figure 6

Divergence time calculation of the isolated Chinese Tconorhini and South American strains

Trypanosoma sp. experimental transmission

Experimental infection of the Chinese Tconorhini showed that the trypanosomes were detected 2 or 3 days after inoculated faeces containing trypanosome were injected through intraperitoneal injection (Additional file 1: Video S2). The Kunming mice and C57BL/6J, BALB/C, BALB/cA-nude and Sprague‒Dawley rats developed low parasitaemia, and the parasitaemia (fewer than 1 × 102 parasites per ml) persisted for more than 1 month. The infected rats and mice did not display symptoms, such as anaemia or depression. Trypanosomes were detected in the Trrubrofasciata faeces at 1 week after feeding on infected mice through optical microscopic observation.

To test the potential for transovarian transmission, experiments were conducted for 20 weeks until all the nymphs of the next generation Trrubrofasciata became adults. No trypanosomes were detected in any of the fresh Trrubrofasciata faeces throughout the experiment.

Investigation of natural Trypanosoma sp. infection

Overall, 49 of the 135 triatomine specimens collected in Guangxi were PCR positive for approximately 600 bp fragments, with an infection rate of 36.30%. The adult and nymph infection rates were 39.3% (24/61) and 33.8% (25/74), respectively. The sequences of the PCR products revealed 98.1–99.7% similarity to the Tconorhini reference strain Tco025E (accession no. MKKU01000460). However, trypanosomes were neither observed or detected by PCR in the blood smears from 16 Rnorvegicus.

Discussion

In this study, we identified Tconorhini isolates from the triatomine Trrubrofasciata in China for the first time. The trypanosome species were confirmed by both morphological and molecular methods. Trypanosome species identification by morphological methods is challenging because molecular methods improve the accuracy of identification. Phylogeny based on the 18S rRNA, HSP70 and gGAPDH genes has been used for evolutionary and taxonomic studies of trypanosomatids, and it is recommended that all new trypanosome species be phylogenetically validated using at least two of these genes [26,27,28,29]. In this case, we employed three genes to confirm this species; with the obtained phylogenetic trees showing that the new Chinese triatomine trypanosomes belong to the Tconorhini clade with limited differences compared with the species documented from the USA and Brazil [30, 31]. This finding is convincing, as the genetic identity is based on both morphological observations and molecular analysis.

Trypanosoma conorhini is one of four trypanosomes (Tcruzi, Trangeli, Tconorhini and Tlewisi) that have been reported to be transmitted by Trrubrofasciata via blood feeding [15]. Therefore, Tconorhini deserves more attention for the following reasons: (1) Tconorhini is a close relative of known human pathogens. The other three trypanosomes found in the Trrubrofasciata are closely related to Tconorhini and known human pathogens. Trypanosoma cruzi and Trangeli cause human infection, and Tlewisi (also isolated from Trrubrofasciata) can cause atypical human infection [32]. The study of Tconorhini revealed that there are human pathogens in addition to Tcruzi, suggesting that Tconorhini should also be classified as a neglected human pathogen even if it is thought to be nonpathogenic to humans and is generally transmitted to a restricted nonhuman host range, where it causes mild and transient infection. For example, laboratory experiments have shown that nonhuman primates can become infected with Tconorhini [12, 13]. More importantly, cutaneous symptoms in humans after bites by Trrubrofasciata are common [16]. (2) Population growth of Trrubrofasciata increases the possibility of human encounters with Tconorhini. After all, Trrubrofasciata is the only globally distributed triatomine, and its prevalence has been reported to increase significantly in several Asian countries [33, 34]. Moreover, previous investigations have shown a rising number of reports of Trrubrofasciata bites in humans across regions of China, which is becoming a public health problem because it can also cause severe anaphylactic reactions [17, 20].

In our study, Chinese Tconorhini was not transovarially transmitted in the Trrubrofasciata. However, the infection ratio of Tconorhini in the Trrubrofasciata reached 36.30%. The prevalence of Tconorhini infection in triatomines in China is very similar to that reported in Vietnam [15]. However, the natural host of this parasite has yet to be identified, and larger-scale investigations are needed. Our results demonstrated that rats and mice could be infected under laboratory conditions with Tconorhini via incubated faeces or bites from the Trrubrofasciata collected from the wild. In turn, the Trrubrofasciata also became infected from ingesting infected rats and mouse blood. This indicated that Trrubrofasciata is a vector for Tconorhini. Furthermore, this is supported by a paper describing a high number of Trrubrofasciata found near chicken coops [20]. Therefore, future work should investigate the possibility of chickens as reservoir hosts.

Finally, we used molecular clock analysis and predicted a divergence time of 1 MYA between Chinese and South American Tconorhini. This corresponds to the time when hominids dominated Asia, i.e. Homo erectus arrived in the southeastern part of Asia at approximately 1.7 MYA [35, 36]. However, it is unclear whether the prevalence of Trrubrofasciata and Tconorhini in Asia can be associated with the hominids of this time period or with other mammals or birds.

In addition to Tconorhini, many new trypanosome species have recently been reported in China, e.g. Tevansi in cattle and buffalo [37]; Tdionisii, Twauwau and other Trypanosoma sp. in bats [38, 39]; Tlewisi from rats and mice [40]; Tcarassii in fish [41]; and Trypanosoma (Megatrypanum) bubalisi sp. nov. in leeches [42]. This finding for Tconorhini in China reflects how limited our knowledge of trypanosomes and vectors is.

Conclusions

In this study, a Trypanosoma sp. was found in Trrubrofasciata in China, the morphology and molecular analysis of which indicated that this trypanosome was Tconorhini. However, we ruled out that transovarial transmission by Trrubrofasciata of this Chinese Tconorhini is not possible; it can be transmitted between Trrubrofasciata and laboratory mice and rats. There was a higher prevalence (> 36%) of Tconorhini in the Trrubrofasciata collected from our collection sites than from mice and rats collected from other sites. Future work should investigate whether Tconorhini is pathogenic to humans.

Availability of data and materials

The data supporting the finds of the study are available within the article and its supplementary materials and genbank.

Abbreviations

NJ:

Neighbour-joining

HSP70:

Heat shock protein 70

gGAPDH:

Glycosomal glyceraldehyde-3-phosphate dehydrogenase

ITS:

Internal transcribed spacer region

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Acknowledgements

We sincerely thank the people who participated in the investigation, including Yaobao Wei from Guangxi Zhuang Autonomous Region Center for Disease Prevention and Control, Chenghui Lao from Hepu County People’s Hospital.

Funding

This work was supported by the National Natural Science Foundation of China (Grant No. 82260413 and 32270446); Youth Science Foundation of Guangxi Medical University (Grant No. GXMUYSF202201); National Key Research and Development Program of China (No. 2021YFC2300803) and Clinical Research Special Project of Shanghai Municipal Health Commission (202140215).

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Authors

Contributions

YLS, QL, DHL and YWL developed the study protocol. YLS, DYL, XYF, YYL, PCD, LLT, XQL, SSH and QL performed the field work and contributed to the data analysis. YLS, QL, DHL and YWL performed the final analysis. YLS, DHL and QL wrote the first manuscript draft. All authors have read and approved the final version of the manuscript.

Corresponding authors

Correspondence to Yanwen Li or Qin Liu.

Ethics declarations

Ethics approval and consent to participate

The Guangxi Medical University Ethics Committee approved the study under licence of Grant No.82260413.

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Not applicable.

Competing interests

The authors declare that they have no competing interests.

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Supplementary Information

Additional file 1: Video S1.

The moving of Trypanosoma sp. in T. rubrofasciata faeces from Guangxi. Video S2. The moving of Trypanosoma sp. in blood of infected mice. Table S1. The trypanosomes sequences information that downloaded from NCBI and used in the phylogenetic analysis.

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Shi, Y., Lai, D., Liu, D. et al. Morphological and molecular characteristics of a Trypanosoma sp. from triatomines (Triatoma rubrofasciata) in China. Parasites Vectors 17, 214 (2024). https://0-doi-org.brum.beds.ac.uk/10.1186/s13071-024-06274-w

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