Tasew Geremew, Gadisa Endalamaw, Abera Adugna, Zewude Aboma, Chanyalew Menberework, Aseffa Abraham, Abebe Markos, Ritter Uwe, van Zandbergen Ger, Laskay Tamás, Tafess Ketema
Ethiopia Public Health Institute, Leishmaniasis Research Laboratory, P.O. Box 1242, Addis Ababa, Ethiopia.
Armauer Hansen Research Institute, Leishmaniasis Research Laboratory, P.O. Box 1005, Addis Ababa, Ethiopia.
Parasit Vectors. 2016 Apr 18;9:218. doi: 10.1186/s13071-016-1441-5.
Epidemiological studies in Ethiopia have documented that the risk of visceral leishmaniasis (VL, Kala-azar) is higher among people living with domestic animals. The recent report on isolation of Leishmania donovani complex DNA and the detected high prevalence of anti-leishmanial antibodies in the blood of domestic animals further strengthen the potential role of domestic animals in the epidemiology of VL in Ethiopia. In mammalian hosts polymorphonuclear cells (PMN) and macrophages are the key immune cells influencing susceptibility or control of Leishmania infection. Thus to substantiate the possible role of cattle in VL transmission we investigate the permissiveness of bovine PMN and monocyte derived macrophages (MDM) for Leishmania (L.) donovani infection.
Whole blood was collected from pure Zebu (Boss indicus) and their cross with Holstein Friesian cattle. L. donovani (MHOM/ET/67/HU3) wild and episomal green fluorescent protein (eGFP) labelled stationary stage promastigotes were co-incubated with whole blood and MDM to determine infection of these cells. Engulfment of promastigotes by the cells and their transformation to amastigote forms in MDM was studied with direct microscopy. Microscopy and flow cytometry were used to measure the infection rate while PCR-RLFP was used to confirm the infecting parasite.
L. donovani infected bovine whole blood PMN in the presence of plasma factors and all cellular elements. Morphological examinations of stained cytospin smears revealed that PMN engulfed promastigotes. Similarly, we were able to show that bovine MDM can be infected by L. donovani, which transformed to amastigote forms in the cells.
The in vitro infection of bovine PMN and MDM by L. donovani further strengthens the possibility that cattle might serve as source of L. donovani infection for humans.
埃塞俄比亚的流行病学研究表明，与家畜共同生活的人群内脏利什曼病（VL，黑热病）的风险更高。最近关于杜氏利什曼原虫复合DNA分离的报告以及在家畜血液中检测到的抗利什曼原虫抗体的高流行率，进一步强化了家畜在埃塞俄比亚VL流行病学中的潜在作用。在哺乳动物宿主中，多形核细胞（PMN）和巨噬细胞是影响利什曼原虫感染易感性或控制感染的关键免疫细胞。因此，为证实牛在VL传播中可能发挥的作用，我们研究了牛PMN和单核细胞衍生巨噬细胞（MDM）对杜氏利什曼原虫感染的易感性。
从纯种泽布牛（瘤牛）及其与荷斯坦弗里生牛的杂交牛采集全血。将杜氏利什曼原虫（MHOM/ET/67/HU3）野生型和附加型绿色荧光蛋白（eGFP）标记的静止期前鞭毛体与全血和MDM共同孵育，以确定这些细胞的感染情况。通过直接显微镜观察研究细胞对前鞭毛体的吞噬作用及其在MDM中转化为无鞭毛体形式的情况。用显微镜和流式细胞术测量感染率，同时用PCR-RLFP确认感染的寄生虫。
在血浆因子和所有细胞成分存在的情况下，杜氏利什曼原虫感染了牛全血PMN。对染色的细胞涂片进行形态学检查发现PMN吞噬了前鞭毛体。同样，我们能够证明牛MDM可被杜氏利什曼原虫感染，且该原虫在细胞内转化为无鞭毛体形式。
杜氏利什曼原虫对牛PMN和MDM的体外感染进一步强化了牛可能作为人类杜氏利什曼原虫感染源的可能性。
