Southeastern Cooperative Wildlife Disease Study, Department of Population Health, The University of Georgia, Athens, GA 30602, USA.
Parasitology. 2010 May;137(6):959-66. doi: 10.1017/S0031182009991995. Epub 2010 Feb 4.
Trypanosoma cruzi (Tc), the causative agent of Chagas disease, is a diverse species with 2 primary genotypes, TcI and TcII, with TcII further subdivided into 5 subtypes (IIa-e). This study evaluated infection dynamics of 4 genetically and geographically diverse T. cruzi strains in 2 South American reservoirs, degus (Octodon degus) and grey short-tailed opossums (Monodelphis domestica). Based on prior suggestions of a genotype-host association, we hypothesized that degus (placental) would more readily become infected with TcII strains while short-tailed opossums (marsupial) would be a more competent reservoir for a TcI strain. Individuals (n=3) of each species were intraperitoneally inoculated with T. cruzi trypomastigotes of TcIIa [North America (NA)-raccoon (Procyon lotor) origin], TcI [NA-Virginia opossum (Didelphis virginiana)], TcIIb [South America (SA)-human], TcIIe (SA-Triatoma infestans), or both TcI and TcIIa. Parasitaemias in experimentally infected degus peaked earlier (7-14 days post-inoculation (p.i.)) compared with short-tailed opossums (21-84 days p.i.). Additionally, peak parasitaemias were higher in degus; however, the duration of detectable parasitaemias for all strains, except TcIIa, was greater in short-tailed opossums. Infections established in both host species with all genotypes, except for TcIIa, which did not establish a detectable infection in short-tailed opossums. These results indicate that both South American reservoirs support infections with these isolates from North and South America; however, infection dynamics differed with host and parasite strain.
克氏锥虫（Tc）是恰加斯病的病原体，是一个具有 2 种主要基因型（TcI 和 TcII）的多样化物种，其中 TcII 进一步分为 5 种亚型（IIa-e）。本研究评估了 4 种具有遗传和地理多样性的 T. cruzi 株在 2 个南美储主（豚鼠和短尾负鼠）中的感染动态。基于先前提出的基因型-宿主关联假设，我们假设豚鼠（胎盘）更容易感染 TcII 株，而短尾负鼠（有袋类）则更适合 TcI 株。每种物种的个体（n=3）均通过腹腔内接种 T. cruzi 锥虫（北美的浣熊起源的 TcIIa、北美的弗吉尼亚负鼠起源的 TcI、南美的人类起源的 TcIIb、南美的 Triatoma infestans 起源的 TcIIe，或 TcI 和 TcIIa 混合）。实验感染的豚鼠的寄生虫血症更早达到高峰（接种后 7-14 天），而短尾负鼠的寄生虫血症高峰则更晚（接种后 21-84 天）。此外，豚鼠的寄生虫血症峰值更高；然而，除 TcIIa 外，所有菌株在短尾负鼠中可检测到的寄生虫血症持续时间更长。除 TcIIa 外，所有宿主和基因型都建立了感染，而 TcIIa 在短尾负鼠中未建立可检测到的感染。这些结果表明，这两个南美储主都支持来自南北美的这些分离株的感染；然而，感染动态因宿主和寄生虫株而异。
