Sharma Rajnish, Parker Sarah, Al-Adhami Batol, Bachand Nicholas, Jenkins Emily
Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.
Centre for Applied Epidemiology, Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada.
Food Waterborne Parasitol. 2019 Mar 8;15:e00046. doi: 10.1016/j.fawpar.2019.e00046. eCollection 2019 Jun.
Toxoplasmosis is an important parasitic zoonosis worldwide. Many human and animal surveys use serological assays based on antibody detection in serum, a matrix that is not routinely available from wildlife. Commonly used serological assays have rarely been validated for use with fluids other than serum, nor validated for their performance in wildlife species. New molecular assays, such as magnetic capture DNA extraction and real-time PCR (MC-qPCR), offer high sensitivity for detection of DNA in tissues. The aims of this study were to (1) assess prevalence of DNA based on MC-qPCR detection in brain and heart of naturally infected wolverines () from the Yukon, Canada (2) compare two matrices [heart fluid (collected from thawed heart) and filter eluate (eluted from blood soaked filter paper)] for antibody detection in the same species, and (3) evaluate the performance of three serological tests [modified agglutination test (MAT), enzyme linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFAT)] to detect naturally infected wolverines as determined by MC-qPCR. DNA of was detected in heart and/or brain in 16 of 68 wolverines (24%, 95% CI: 15.0-34.8). Tissue prevalence and infection intensity was higher in heart [16 positives, mediantachyzoites equivalents per gram (TEG) =1221] compared to brain (10 positives, median TEG = 347). Heart fluid (HF) and filter eluates (FE) performed equally well in ELISA and IFAT in terms of relative sensitivity, but HF performed better with MAT. ELISA and IFAT had higher relative sensitivity (94%) and relative specificity (100%) compared to MAT (relative sensitivity 75% and relative specificity 92%). Overall, our findings indicate that the parasite burden in naturally infected wolverines was higher in heart compared to brain, heart fluid performed better than filter paper eluate for serological testing using MAT, and both IFAT and ELISA had higher relative sensitivity, relative specificity, and accuracy compared to MAT.
弓形虫病是一种在全球范围内重要的寄生虫人畜共患病。许多针对人类和动物的调查使用基于血清中抗体检测的血清学检测方法，而血清这种样本并非野生动物常规可获取的。常用的血清学检测方法很少针对血清以外的其他样本进行验证，也未针对其在野生动物物种中的性能进行验证。新的分子检测方法，如磁捕获DNA提取和实时PCR（MC-qPCR），对组织中DNA的检测具有高灵敏度。本研究的目的是：（1）基于MC-qPCR检测评估加拿大育空地区自然感染的狼獾大脑和心脏中DNA的流行率；（2）比较同一物种中用于抗体检测的两种样本[心脏液体（从解冻的心脏中采集）和滤膜洗脱液（从浸血滤纸上洗脱）]；（3）评估三种血清学检测方法[改良凝集试验（MAT）、酶联免疫吸附测定（ELISA）和间接荧光抗体试验（IFAT）]检测由MC-qPCR确定的自然感染狼獾的性能。在68只狼獾中有16只（24%，95%置信区间：15.0 - 34.8）在心脏和/或大脑中检测到了弓形虫DNA。与大脑（10只阳性，每克速殖子当量中位数（TEG）=347）相比，心脏中的组织流行率和感染强度更高[16只阳性，每克速殖子当量中位数（TEG）=1221]。就相对灵敏度而言，心脏液体（HF）和滤膜洗脱液（FE）在ELISA和IFAT中的表现相当，但HF在MAT检测中表现更好。与MAT（相对灵敏度75%，相对特异性92%）相比，ELISA和IFAT具有更高的相对灵敏度（94%）和相对特异性（100%）。总体而言，我们的研究结果表明，自然感染的狼獾中，心脏中的寄生虫负荷高于大脑；在使用MAT进行血清学检测时，心脏液体比滤纸洗脱液表现更好；与MAT相比，IFAT和ELISA都具有更高的相对灵敏度、相对特异性和准确性。
