Murambiwa Pretty, Silas Ekuyikeno, Mdleleni Yanga, Mukaratirwa Samson
School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban, 4000, South Africa.
One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis.
Heliyon. 2020 Feb 25;6(2):e03475. doi: 10.1016/j.heliyon.2020.e03475. eCollection 2020 Feb.
Malaria remains a major cause of mortality and morbidity in sub-Saharan Africa (SSA) and tissue-dwelling helminth parasites (TDHPs) are also prevalent in this region presenting a geographical overlap in endemicity. There is paucity of information on the specific host immune responses elicited at different phases of the life cycle by the co-infecting helminth parasites. This study aimed at using a laboratory animal model to determine selected chemokine, cytokine and hematological profiles in Sprague-Dawley rats co-infected with ANKA (Pb) and a tissue-dwelling nematode, (Tz). One-hundred-and-sixty-eight male Sprague-Dawley rats (90-150g) were randomly divided into four experimental groups; Control (n = 42), Pb-infected (n = 42), Tz-infected (n = 42) and Pb Tz-infected group (n = 42). infection (3 muscle larvae/g body weight ) was done on day 0 while intra-peritoneal Pb infection (10 parasitised RBCs) was done at day 28 of the 42-day experimental study for the co-infection group which corresponded with day 0 of the Pb group on the protocol. Haematological parameters, cytokines (TNF-α, IL-10, IL-4, IL-6), chemokines (CXCL10, CCL5, CCL11) and burden of Tz adult worms and muscle larvae burden were determined as per need for each group. Results showed that Tz infection predisposed the co-infected animals towards rapid development of Pb parasitaemia during co-infection, reaching a higher peak percentage parasitaemia at day 7 post-infection than the Pb mono-infected group at day 6 post-infection. Animals in the co-infected group also exhibited severe anaemia, basophilia, neutrophilia, eosinophilia and lymphopenia at day 7 post Pb infection compared to the control groups. Significant elevation of Pb parasitaemia coincided with elevated pro-inflammatory cytokine TNF-α ( 0.001), regulatory anti-inflammatory IL-10 ( 0.001), and pro-inflammatory chemokines CXCL10 ( 0.001) concentration in comparison to control group, at day 7 post Pb infection. Our results confirm that co-infection of Pb with Tz resulted in increased Pb parasitaemia compared to the control group in the early stages of infection and this might translate to severe malaria.
疟疾仍然是撒哈拉以南非洲地区（SSA）死亡和发病的主要原因，而组织内寄生蠕虫寄生虫（TDHPs）在该地区也很普遍，在流行区域存在地理重叠。关于共感染的蠕虫寄生虫在生命周期不同阶段引发的特定宿主免疫反应的信息很少。本研究旨在使用实验动物模型来确定同时感染ANKA（Pb）和一种组织内寄生线虫（Tz）的Sprague-Dawley大鼠中选定的趋化因子、细胞因子和血液学特征。168只雄性Sprague-Dawley大鼠（90-150克）被随机分为四个实验组；对照组（n = 42）、感染Pb组（n = 42）、感染Tz组（n = 42）和同时感染Pb和Tz组（n = 42）。在第0天进行Tz感染（3条肌幼虫/克体重），而对于共感染组，在42天实验研究的第28天进行腹腔内Pb感染（10个寄生红细胞），这与Pb组方案中的第0天相对应。根据每组的需要测定血液学参数、细胞因子（TNF-α、IL-10、IL-4、IL-6）、趋化因子（CXCL10、CCL5、CCL11）以及Tz成虫负担和肌幼虫负担。结果表明，Tz感染使共感染动物在共感染期间更容易快速发展为Pb血症，在感染后第7天达到的寄生虫血症峰值百分比高于感染后第6天的Pb单感染组。与对照组相比，共感染组的动物在Pb感染后第7天还表现出严重贫血、嗜碱性粒细胞增多、嗜中性粒细胞增多、嗜酸性粒细胞增多和淋巴细胞减少。与对照组相比，在Pb感染后第7天，Pb血症的显著升高与促炎细胞因子TNF-α（P<0.001）、调节性抗炎因子IL-10（P<0.001）和促炎趋化因子CXCL10（P<0.001）浓度升高同时出现。我们的结果证实，与对照组相比，在感染早期Pb与Tz共感染导致Pb血症增加，这可能转化为严重疟疾。
