Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
The Netherlands Food and Consumer Product Safety Authority (NVWA), Centre Monitoring Vectors, Wageningen, The Netherlands.
Parasit Vectors. 2019 Nov 21;12(1):556. doi: 10.1186/s13071-019-3810-3.
The aim of this study was to assess potential associations between Giardia duodenalis infection in dogs, as determined by three diagnostic tests, and dog's group of origin, fecal consistency, age, sex, neuter status, and co-infections with other gastrointestinal parasites.
Fecal samples from 1291 dogs from four groups (household, shelter, hunting and clinical dogs) were tested with qPCR, rapid enzyme immunochromatographic assay (IDEXX SNAP Giardia), and direct immunofluorescence (DFA, Merifluor) for presence of G. duodenalis. Moreover, fecal samples were tested with centrifugation sedimentation flotation (CSF) coproscopical analysis for presence of gastrointestinal parasites. Associations were expressed as odds ratios (ORs).
Several significant associations were found, of which a few were consistent for all three tests and Giardia positivity in general (positive with at least one of these tests). Dogs older than one year were significantly less likely to test positive for Giardia than younger dogs. Group-housed dogs, especially hunting dogs, were significantly more likely to test positive for Giardia compared to household and clinical dogs. A consistently significant association with Trichuris appeared to be driven by the high prevalence in hunting dogs. Although there was no significant association between loose stool and Giardia infection in the overall population, household dogs were significantly more likely to test Giardia-positive when having loose stool. Overall, Giardia-positive dogs with loose stool shed significantly more cysts, both determined semi-quantitatively with CSF and quantitatively by qPCR, than positive dogs with no loose stool. When other gastrointestinal parasites were present, significantly fewer cysts were detected with CSF, but this was not confirmed with qPCR.
Giardia is the most common gastrointestinal parasite in Dutch dogs, except for hunting dogs, in which Trichuris and strongyle-type eggs (hookworms) prevailed. Giardia infection was not significantly associated with loose stool, except for household dogs. Young dogs and group-housed dogs were significantly more often Giardia-positive. These associations were consistent across diagnostic tests. Young dogs, clinical dogs and dogs with loose stool shed Giardia cysts in the highest numbers. If another gastrointestinal parasite was present lower numbers of cysts were observed by microscope (CSF), but not with a molecular method (qPCR).
本研究旨在评估三种诊断方法检测到的犬贾第鞭毛虫感染与犬的来源群体、粪便稠度、年龄、性别、绝育状态以及与其他胃肠道寄生虫的合并感染之间的潜在关联。
对来自四个群体（家庭、收容所、狩猎和临床）的 1291 只犬的粪便样本进行 qPCR、快速酶免疫层析检测（IDEXX SNAP Giardia）和直接免疫荧光（Merifluor）检测，以确定是否存在贾第鞭毛虫。此外，通过离心沉淀浮聚法（CSF）粪便镜检分析检测是否存在胃肠道寄生虫。关联以比值比（OR）表示。
发现了一些具有统计学意义的关联，其中一些关联对所有三种检测方法和一般的贾第鞭毛虫阳性都具有一致性（至少有一种检测方法呈阳性）。一岁以上的犬比年幼的犬检测出贾第鞭毛虫阳性的可能性显著降低。群体饲养的犬，特别是狩猎犬，与家庭犬和临床犬相比，检测出贾第鞭毛虫阳性的可能性显著更高。与 Trichuris 出现一致的显著关联似乎是由狩猎犬中的高患病率驱动的。尽管在总体人群中，稀便与贾第鞭毛虫感染之间没有显著关联，但家庭犬出现稀便时，检测出贾第鞭毛虫阳性的可能性显著更高。总体而言，与无稀便的阳性犬相比，有稀便的阳性犬通过 CSF 半定量和 qPCR 定量检测，排出的包囊数量显著更多。当存在其他胃肠道寄生虫时，通过 CSF 检测到的包囊数量显著减少，但这一结果并未通过 qPCR 得到证实。
除了狩猎犬以外，贾第鞭毛虫是荷兰犬中最常见的胃肠道寄生虫，而在狩猎犬中， Trichuris 和 Strongyle 型卵（钩虫）则更为流行。除了家庭犬，贾第鞭毛虫感染与稀便之间没有显著关联。年幼的犬和群体饲养的犬更容易感染贾第鞭毛虫。这些关联在所有诊断测试中都是一致的。年幼的犬、临床犬和有稀便的犬排出的贾第鞭毛虫包囊数量最多。如果存在其他胃肠道寄生虫，通过显微镜（CSF）观察到的包囊数量会减少，但通过分子方法（qPCR）则不会。
