Nehra A K, Gowane G R, Kuriyal A, Chaurasiya A, Kumar R, Bhinsara D B, Parthasarathi B C, Bhawana K, Khare R K, Prasad A, Chandra D, Sankar M
Division of Temperate Animal Husbandry, Indian Veterinary Research Institute, Mukteswar Campus, India.
ICAR-Central Sheep and Wool Research Institute, Avikanagar, India.
Vet Parasitol. 2019 Mar;267:47-53. doi: 10.1016/j.vetpar.2019.01.005. Epub 2019 Jan 29.
Haemonchosis commonly occurs as chronic and subclinical infection in small ruminants, and understanding of immunological response against subclinical haemonchosis is of paramount importance for designing and implementing effective control strategies. The present study was designed to evaluate immunological response during subclinical haemonchosis, experimentally established in goats. Sixteen 5-6 month-old helminth naive kids were randomly allocated into one of two groups, infected and uninfected; the infected group being infected per os with 250 Haemonchus contortus larvae per kg body weight. Faecal, blood and serum samples were collected every third day up to 30 days post-infection (DPI), thereafter weekly up to 58 DPI to record changes in faecal egg count (FEC), haemoglobin (Hb), packed cell volume (PCV), peripheral eosinophil percentage and immunological parameters, such as macrophage cytokine interleukin-12 (IL-12), Th1 cytokine (IFN-γ), Th2 cytokines (IL-4, 13, 25, 33) and immunoglobulins (IgG and IgE). Pre-patent period of H. contortus in the present study was 18 days and eggs per gram (EPG) peaked on 30 DPI. The total reduction in body weight gain in the infected group was 26 g per day when compared with uninfected animals. Hb (7.35 ± 0.34 g/dL in infected animals compared with 9.76 ± 0.67 in control animals) and PCV levels (22 ± 1.54 g/dL in infected animals compared with 29.2 ± 1.27 in control animals) decreased significantly up to 44 DPI in infected group (P = 0.000). IL-4, IL-13, IL-33, IgG and IgE showed significant increase in infected animals at different periods. IFN-γ, IL-12 and IL-25 did not show any significant changes barring a steep rise of IFN-γ on 27 DPI. A positive correlation was observed between IgE and IL-4 in subclinical haemonchosis. Of particular note was that all the major cytokines, such as IFN-γ (P = 0.000), IL-4 (P = 0.000), IL-13 (P = 0.009), and both IgG (P = 0.000) and IgE (P = 0.003), were observed at the lowest concentration on 24 DPI. The effect of infection was found to be significant on cytokines with a strong interaction with time. Taken together, the data suggest that Th2 immune response is predominating in subclinical haemonchosis. The economic loss in term of body weight gain due to subclinical haemonchosis was considerable.
捻转血矛线虫病在小型反刍动物中通常表现为慢性和亚临床感染，了解针对亚临床捻转血矛线虫病的免疫反应对于设计和实施有效的防控策略至关重要。本研究旨在评估山羊实验性建立的亚临床捻转血矛线虫病期间的免疫反应。16只5至6月龄未感染过蠕虫的羔羊被随机分为两组，即感染组和未感染组；感染组每千克体重经口感染250条捻转血矛线虫幼虫。在感染后30天内每隔三天采集粪便、血液和血清样本，此后每周采集直至感染后58天，以记录粪便虫卵计数（FEC）、血红蛋白（Hb）、红细胞压积（PCV）、外周嗜酸性粒细胞百分比以及免疫参数的变化，如巨噬细胞细胞因子白细胞介素-12（IL-12）、Th1细胞因子（IFN-γ）、Th2细胞因子（IL-4、13、25、33）和免疫球蛋白（IgG和IgE）。本研究中捻转血矛线虫的潜伏期为18天，每克虫卵数（EPG）在感染后30天达到峰值。与未感染动物相比，感染组体重增加的总减少量为每天26克。感染组的Hb（感染动物为7.35±0.34克/分升，对照组为9.76±0.67克/分升）和PCV水平（感染动物为22±1.54克/分升，对照组为29.2±1.27克/分升）在感染后44天内显著下降（P = 0.000）。IL-4、IL-13、IL-33、IgG和IgE在感染动物的不同时期均显著增加。IFN-γ、IL-12和IL-25除了在感染后27天IFN-γ急剧上升外，没有显示出任何显著变化。在亚临床捻转血矛线虫病中，观察到IgE与IL-4之间呈正相关。特别值得注意的是，所有主要细胞因子，如IFN-γ（P = 0.000）、IL-4（P = 0.000）、IL-13（P = 0.009）以及IgG（P = 0.000）和IgE（P = 0.003），在感染后24天观察到处于最低浓度。发现感染对细胞因子有显著影响，且与时间有强烈的相互作用。综上所述，数据表明在亚临床捻转血矛线虫病中Th2免疫反应占主导。亚临床捻转血矛线虫病导致的体重增加方面的经济损失相当可观。
