Gibson W C, Stevens J R, Mwendia C M, Ngotho J N, Ndung'u J M
School of Biological Sciences, University of Bristol, UK.
Parasitology. 2001 Jun;122(Pt 6):625-31. doi: 10.1017/s0031182001007880.
African trypanosomes of the subgenera Nannomonas and Pycnomonas have been recorded from both wild and domestic suids. However, complete descriptions of some of these trypanosomes with regard to host range, pathogenicity, transmission and distribution are still lacking. Neither the recently described Trypanosoma (Nannomonas) godfreyi nor Trypanosoma (Nannomonas) congolense Tsavo have been isolated from mammalian hosts, while Trypanosoma (Pycnomonas) suis remains the rarest of the Salivarian trypanosomes. The only isolate presumed to be of the latter species is maintained at the Kenya Trypanosomiasis Research Institute, Nairobi. We present here the results of characterization of this isolate by morphology, tsetse transmission, the use of species-specific DNA probes and DNA sequence analysis. Morphology in stained blood smears revealed a small trypanosome with a free flagellum. Experimental transmission through Glossina morsitans morsitans showed a developmental cycle typical of subgenus Nannomonas A positive identification was obtained with species-specific PCR primers for T. congolense Tsavo; moreover, the sequence of the SSU rRNA gene was almost identical to that of T. congolense Tsavo on database. In phylogenetic analysis of the SSU rRNA genes of Salivarian trypanosomes, T. congolense Tsavo grouped with T. simiae rather than T. congolense, suggesting that the name T. simiae Tsavo is more appropriate.
Nannomonas和Pycnomonas亚属的非洲锥虫已在野生和家养猪科动物中被记录到。然而，关于其中一些锥虫在宿主范围、致病性、传播和分布方面的完整描述仍然缺乏。最近描述的戈氏锥虫（Nannomonas亚属）和察沃刚果锥虫（Nannomonas亚属）都未从哺乳动物宿主中分离出来，而猪锥虫（Pycnomonas亚属）仍然是唾液传播锥虫中最罕见的。唯一被认为是后一种锥虫的分离株保存在内罗毕的肯尼亚锥虫病研究所。我们在此展示通过形态学、采采蝇传播、使用种特异性DNA探针和DNA序列分析对该分离株进行鉴定的结果。染色血涂片的形态学显示为一种带有游离鞭毛的小型锥虫。通过冈比亚采采蝇进行的实验性传播显示出Nannomonas亚属典型的发育周期。使用察沃刚果锥虫的种特异性PCR引物获得了阳性鉴定结果；此外，小亚基核糖体RNA（SSU rRNA）基因的序列与数据库中察沃刚果锥虫的序列几乎相同。在对唾液传播锥虫的SSU rRNA基因进行系统发育分析时，察沃刚果锥虫与猕猴锥虫归为一类，而不是与刚果锥虫归为一类，这表明察沃猕猴锥虫这个名称更合适。
