Postgraduate Program in Animal Science and Health, Federal University of Campina Grande - UFCG, Patos, PB, Brazil.
Postgraduate Program in Animal Science and Health, Federal University of Campina Grande - UFCG, Patos, PB, Brazil.
Exp Parasitol. 2022 May-Jun;236-237:108233. doi: 10.1016/j.exppara.2022.108233. Epub 2022 Feb 18.
Dirofilaria immitis is a zoonotic filarid that mainly affects the domestic dog, causing a generally fatal chronic disease, known as heart worm disease. In addition to dogs, the parasite can affect wild canids, cats, and humans. Due to its importance to One Health, detection of parasitism by D. immitis in dogs can help the adoption of control measures that aim to reduce the occurrence of parasitosis in animals and humans. The detection of D. immitis is based on the use of parasitological, serological, and molecular methods, which vary in sensitivity and specificity. Therefore, the objective was to evaluate and compare the efficiency and performance of parasitological, serological, and molecular tests in the detection of D. immitis in dogs in Northeastern Brazil. Whole blood and serum from 140 dogs from the municipality of Sousa were used, varying between males and females; aged one to 17 years; pure and mixed breeds; domiciled and stray. Three microscopic parasitological techniques (MPT) were used: capillary blood smear (CBS), peripheral (PBS) and modified Knott test (MK) associated with the morphometric diagnosis of the microfilariae. For the detection of D. immitis antigens, a rapid immunochromatographic test (RIT) (ALERE Dirofilariose AG Teste kit®, Seogu-dong, Korea) was used, and polymerase chain reaction (PCR) as a molecular method. To evaluate the tests, PCR was considered the gold standard, and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) values were calculated. To verify the agreement of the tests, the Kappa test was performed (p ≤ 0.05). From the 140 analyzed samples, 33.6% (48/140) presented microfilariae, antigen and/or parasitic DNA. 23.6% (33/140) were positive in the CBS; 25.7% (36/140) in the PBS; 29.3% (41/140) in the MK; 30% (42/140) in the RIT and 28.6% (40/140) in the PCR. All methods showed almost perfect agreement with PCR, high sensitivity (0.8-0.95), specificity (0.94-0.99), and values established with VPP (0.8571-0.9722) and VPN (0.9519-0.9797). The CBS and PBS showed less sensitivity and greater specificity. MK presented the highest sensitivity and RIT was the choice for hidden infections. Considering the occurrence of D. immitis in dogs in a non-coastal region of Northeastern Brazil, an epidemiological approach is recommended to identify risk factors for this zoonotic parasitosis.
犬恶丝虫是一种主要感染家犬的动物寄生丝虫，会引起一种通常致命的慢性疾病，称为心丝虫病。除了犬类，这种寄生虫还会感染野生犬科动物、猫和人类。由于它对“One Health”的重要性，检测犬类体内的犬恶丝虫寄生情况有助于采取控制措施，以减少动物和人类的寄生虫病发生。犬恶丝虫的检测基于寄生虫学、血清学和分子方法，这些方法在灵敏度和特异性方面存在差异。因此，本研究的目的是评估和比较寄生虫学、血清学和分子检测方法在检测巴西东北部犬恶丝虫的效率和性能。本研究使用了来自苏萨市的 140 只犬的全血和血清，包括雄性和雌性、1 至 17 岁的犬、纯种犬和混种犬、家养犬和流浪犬。使用了三种显微镜寄生虫学技术（MPT）：毛细血管血涂片（CBS）、外周血涂片（PBS）和改良 Knott 试验（MK），并结合微丝蚴的形态学诊断。为了检测犬恶丝虫抗原，使用了一种快速免疫色谱检测（RIT）（ALERE Dirofilariose AG Teste kit®，Seogu-dong，韩国），并使用聚合酶链反应（PCR）作为分子方法。为了评估这些检测方法，PCR 被认为是金标准，并计算了灵敏度、特异性、阳性预测值（PPV）和阴性预测值（NPV）。为了验证检测方法的一致性，进行了 Kappa 检验（p≤0.05）。在分析的 140 个样本中，33.6%（48/140）的样本中检测到微丝蚴、抗原和/或寄生虫 DNA。CBS 的阳性率为 23.6%（33/140），PBS 为 25.7%（36/140），MK 为 29.3%（41/140），RIT 为 30%（42/140），PCR 为 28.6%（40/140）。所有方法与 PCR 均具有几乎完美的一致性，具有较高的灵敏度（0.8-0.95）、特异性（0.94-0.99），以及经 VPP（0.8571-0.9722）和 VPN（0.9519-0.9797）建立的阳性预测值和阴性预测值。CBS 和 PBS 的灵敏度较低，特异性较高。MK 的灵敏度最高，RIT 是检测隐性感染的首选方法。考虑到巴西东北部非沿海地区犬类中犬恶丝虫的发生情况，建议采用流行病学方法来确定这种人畜共患寄生虫病的危险因素。
