犬心丝虫和热处理：使用基于酶联免疫吸附试验（ELISA）和具有明确心丝虫感染状态的犬血清进行评估。

Canine heartworm and heat treatment: An evaluation using a well based enzyme-linked immunosorbent assay (ELISA) and canine sera with confirmed heartworm infection status.

机构信息

Department of Comparative, Diagnostic and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.

Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Al 36849, USA.

出版信息

Vet Parasitol. 2020 Jul;283:109169. doi: 10.1016/j.vetpar.2020.109169. Epub 2020 Jun 20.

DOI:10.1016/j.vetpar.2020.109169

PMID:32593059

Abstract

Heat treatment of serum has demonstrated improved detection of Dirofilaria immitis antigen in sera of sheltered dogs without knowing the true infection status of the animals and in dogs confirmed experimentally to be infected with heartworm. Utilizing archived sera with necropsy confirmed heartworm infection status (n = 665) and a micro-titer well based ELISA antigen assay, this study evaluated how the composition of heartworm infections affects antigen test results pre- and post-heat treatment, determined subsequent changes to the antigen test sensitivity and specificity, and application of optical density values. The composition of heartworm infections present in dogs with sera initially testing antigen negative consisted of infections by dead 1/34 (2.9 %), immature 10/34 (29.4 %), male only 7/34 (20.6 %), female only 5/34 (14.7 %), and mixed sex infections 11/34 (32.4 %) with 2-62 heartworms of which 6 were microfilaremic. The composition of heartworm infections remaining antigen negative post-heat treatment consisted of infections by dead 1/14 (7.1 %), immature 9/14 (64.3 %), male only 2/14 (14.3 %), and mixed sex infections 2/14 (14.3 %) with 6 and 62 heartworms of which 1 was microfilaremic. The overall sensitivity for all infections, mature heartworms, and mature females before heat treatment were 86.9 %, 90.7 %, and 93.3 % and after heat treatment sensitivity increased to 94.6 %, 98.4 %, and 99.2 % respectively. A decrease in specificity from 97.8%-96.1% was observed following heat treatment of heartworm negative sera. Optical density values for the varying infection intensities present in this study clearly indicate that result intensity is not reflective of the number of heartworms present. This study provides additional context for interpreting post-heat antigen results for dogs originating from animal shelters, demonstrates diagnostic utility of optical density, and highlights the need for improved heartworm diagnostics.

摘要

血清热处理已证明可提高对收容所犬血清中犬恶丝虫抗原的检测，而无需了解动物的真实感染状况，并且在经实验证实感染心丝虫的犬中也是如此。利用具有尸检证实的心丝虫感染状态的存档血清（n=665）和基于微量滴定板的 ELISA 抗原检测，本研究评估了心丝虫感染的组成如何影响热处理前后抗原检测结果，确定了随后对抗原检测敏感性和特异性的变化，以及光密度值的应用。在最初检测抗原阴性的血清中存在的犬恶丝虫感染组成包括：34 分之一死亡（2.9%），10/34 不成熟（29.4%），仅雄性 7/34（20.6%），仅雌性 5/34（14.7%）和混合性别感染 11/34（32.4%），其中 6 只是微丝蚴血症。热处理后抗原仍为阴性的犬恶丝虫感染组成包括：34 分之一死亡（7.1%），9/14 不成熟（64.3%），仅雄性 2/14（14.3%）和混合性别感染 2/14（14.3%），其中 6 只是微丝蚴血症，1 只是微丝蚴血症。热处理前所有感染、成熟心丝虫和成熟雌虫的总敏感性分别为 86.9%、90.7%和 93.3%，热处理后敏感性分别提高至 94.6%、98.4%和 99.2%。心丝虫阴性血清热处理后特异性从 97.8%-96.1%下降。本研究中存在的不同感染强度的光密度值清楚地表明，结果强度与存在的心丝虫数量无关。本研究为解释动物收容所来源犬的热处理后抗原结果提供了更多背景信息，证明了光密度的诊断实用性，并强调了改进心丝虫诊断的必要性。