Trypanosomatid Infections among Vertebrates of Chile: A Systematic Review

Abstract

We present a review on the natural infection by trypanosomatids of nonhuman vertebrates in Chile, aiming to synthesize and update the knowledge on the diversity of trypanosomatids infecting native and alien vertebrate species. To this end, we conducted a systematic review of literature records published from 1900 to April 2020 on four databases, focusing on the 21 genera of trypanosomatids and Chile. The methods and findings of our review have been based on the preferred reporting items for systematic reviews and meta-analysis (prisma) checklist. We found 29,756 records but only 71 presented relevant information for this review. Overall, there are only two reported trypanosomatid genera infecting vertebrate species in Chile, the genera Trypanosoma and Leishmania. The former is mostly represented by Trypanosoma cruzi (90% of the total records) and to a much lesser extent by Trypanosoma avium, Trypanosoma humboldti, Trypanosoma lewisi, and a couple of unidentified trypanosomatids. A total of 25 mammals have been reported as being infected by T. cruzi, including 14 native and 11 alien species from Orders Artiodactyla, Carnivora, Chiroptera, Didelphimorphia, Lagomorpha, Perissodactyla, and Rodentia. Extensive screening studies using new analytical tools are necessary to grasp the whole potential diversity of trypanosomatid species infecting vertebrates in Chile.

Keywords: Chagas disease; Mepraia; Triatoma infestans; Trypanosoma cruzi; domestic mammals; exotic mammals; hosts; native mammals; reservoirs; vector-borne parasite.

Figure 1

PRISMA (preferred reporting items for systematic review and meta-analysis) flowchart diagram of the record selection process. Additional records included in this review are depicted in a red box.

Figure 2

Map of Chile depicting the geographic location and the biomes used by triatomines and vertebrate species infected by trypanosomatids, and a reference map showing the location of Chile in South America. Colors in the vertebrate species indicate infection by Leishmania (green), Trypanosoma avium (dark yellow), Trypanosoma cruzi (black), Trypanosoma humboldti (blue), Trypanosoma lewisi (red), unidentified Trypanosoma sp. or trypanosomatid (brown). On the left, species scientific names are indicated. Native and alien vertebrate species infected by T. cruzi are shown to the right and left of Chile, respectively, in colored boxes representing the color of the biome where these infected vertebrates were detected. For the rest of the trypanosomatid-infected species, the exact locations are shown. The distribution of triatomine species includes Mepraia gajardoi, M. parapatrica, M. spinolai, and Triatoma infestans. Division lines inside the Chilean territory represent the administrative regions from North to South: Arica y Parinacota, Tarapacá, Antofagasta, Atacama, Coquimbo, Valparaíso, Metropolitana, O’Higgins, Maule, Biobío, Araucanía, Los Ríos, and Los Lagos. The zoom on the Pacific Ocean corresponds to Robinson Crusoe island from the Juan Fernández Archipelago.

Figure 3

Number of records per decade published on Trypanosoma cruzi infection according to diagnostic techniques on alien (A) and native (N) mammals from Chile. When a record presented two diagnostic techniques, this record was assigned to both techniques, the same as when it presented both native and alien species. Techniques: optical microscopy on blood; xenodiagnosis; serology including IHA (indirect hemagglutination), IIF (indirect immunofluorescence), and ELISA (enzyme-linked immunosorbent assay); PCR (polymerase chain reaction), including cPCR (conventional PCR), cPCR+SB (cPCR and Southern blot), hnPCR (hemi-nested PCR), nPCR (nested PCR), real-time PCR, and qPCR (quantitative PCR).