Kleintierklinik in Iffezheim, An der Rennbahn 16a, 76473 Iffezheim, Germany.
Parasit Vectors. 2013 Feb 25;6:48. doi: 10.1186/1756-3305-6-48.
Considering the increasing importance of small animals travel medicine and the spread of filariae with zoonotic potential to non-endemic European areas, routine filarial diagnosis in dogs is becoming important. Dirofilaria immitis, D. repens, Acanthocheilonema dracunculoides and A. reconditum are the most common canine filarial nematodes presenting blood circulating microfilariae (mf) which can be differentiated to species level by the acid phosphatase activity patterns or by PCR. Available data on the size of the mf vary considerably in the literature. The aim of this study was to validate morphometric criteria for filarial identification in blood samples of dogs after concentration of mf with the modified Knott's technique.
Morphometric analysis of 10 mf from samples identified to species level by acid phosphatase activity and partially confirmed by PCR were performed with specimens from 377 dogs.
The mean length and width of D. immitis mf from 60 dogs were 301.77 ± 6.29 μm and 6.30 ± 0.26 μm, of D. repens mf from 171 dogs 369.44 ± 10.76 μm 8.87 ± 0.58 μm, of A. dracunculoides mf from 133 dogs 259.43 ± 6.69 μm and 5.09 ± 0.47 μm and of A. reconditum mf from 13 dogs 264.83 ± 5.47 μm and 4.63 ± 0.52 μm.For a subset of 30 samples, morphometric analysis was repeated with identical results in two laboratories. Furthermore, the size of mf concentrated and fixed by the Knott's technique was shown to be stable over 105 days.
The Knott's test enables to clearly distinguish between D. immitis, D. repens and Acanthocheilonema spp. However, due to the overlapping size ranges of A. dracunculoides and A. reconditum, biochemical or molecular methods are required to distinguish these two species.
考虑到小动物旅行医学的重要性日益增加，以及具有人畜共患潜力的丝虫传播到非流行地区，犬类常规丝虫诊断变得越来越重要。犬恶丝虫、犬复孔绦虫、旋尾丝虫和细颈囊尾蚴是最常见的犬类丝虫，它们会在血液中循环微丝蚴（mf），这些 mf 可以通过酸性磷酸酶活性模式或 PCR 区分到种的水平。文献中关于 mf 大小的可用数据差异很大。本研究的目的是验证改良 Knott 技术浓缩 mf 后犬血液中丝虫鉴定的形态计量学标准。
对通过酸性磷酸酶活性鉴定到种水平并部分通过 PCR 确认的 377 只犬的 10 只 mf 进行形态计量分析。
60 只犬的犬恶丝虫 mf 的平均长度和宽度分别为 301.77 ± 6.29 μm 和 6.30 ± 0.26 μm，171 只犬的犬复孔绦虫 mf 分别为 369.44 ± 10.76 μm 和 8.87 ± 0.58 μm，133 只犬的旋尾丝虫 mf 分别为 259.43 ± 6.69 μm 和 5.09 ± 0.47 μm，13 只犬的细颈囊尾蚴 mf 分别为 264.83 ± 5.47 μm 和 4.63 ± 0.52 μm。对 30 个样本的子集进行了两次重复的形态计量分析，结果完全一致。此外，Knott 技术浓缩和固定的 mf 在 105 天内大小稳定。
Knott 试验能够清楚地区分犬恶丝虫、犬复孔绦虫和旋尾丝虫。然而，由于旋尾丝虫和细颈囊尾蚴的大小范围重叠，需要生化或分子方法来区分这两个物种。
