Miró Guadalupe, Checa Rocío, Paparini Andrea, Ortega Nieves, González-Fraga José Luís, Gofton Alex, Bartolomé Adrián, Montoya Ana, Gálvez Rosa, Mayo Pedro Pablo, Irwin Peter
Department of Animal Health, Veterinary Faculty, Universidad Complutense de Madrid, Madrid, Spain.
Vector- and Water-Borne Pathogen Research Group, School of Veterinary & Life Sciences, Murdoch University, Murdoch, WA, Australia.
Parasit Vectors. 2015 Apr 10;8:217. doi: 10.1186/s13071-015-0825-2.
In north-western Spain, piroplamosis caused by Theileria annae is now recognized as a serious problem because veterinarians, despite being aware of the clinical signs of piroplasmosis, lack the necessary information on its epidemiology or specific diagnostic tools for its management. This, along with the fact that T. annae infection is also refractory to current piroplamosis treatments, prompted this study designed to assess the clinical presentation and diagnosis of this largely unknown parasitic disease in dogs.
One hundred and twenty dogs in NW Spain suspected clinically of having piroplasmosis were examined and piroplasm species detected by light microscopy (LM) observation of Giemsa-stained blood smears, immunofluorescent antibody test (IFAT), and PCR plus sequencing.
Seventy five of the sick dogs were confirmed to be infected with T. annae by PCR (designated "true infection cases"). Intraerythrocytic ring-shaped bodies morphologically compatible with small piroplasms were observed by LM in 59 (57 true infections) of the 120 blood samples. Anti-Babesia antibodies were detected by IFAT in 59 of the 120 sera (55 of which were "true infections"). Using PCR as the reference method, moderate agreement was observed between positive LM vs PCR and IFAT vs PCR results (kappa values: 0.6680 and 0.6017, respectively). Microscopy examination and IFAT were moderately sensitive in detecting the pathogen (76% and 73.3%, respectively). In the 75 cases of "true infection", the most common clinical signs observed were pale mucous membranes, anorexia and apathy. Blood cell counts consistently revealed severe regenerative anaemia and thrombocytopenia in dogs with piroplasmosis due to T. annae. Young dogs (≤3 year) (p = 0.0001) were more susceptible to the disease.
Microscopy showed moderate diagnostic sensitivity for acute T. annae infection while IFAT-determined antibody titres were low (1/64 to 1/128). The infecting species should be therefore confirmed by molecular tests. Our results suggest that the disease affects dogs in regions of Spain bordering the endemic Galicia area where this piroplasm has not been previously reported (Asturias, northern Spain). Further epidemiological surveys based on serological and molecular methods are required to establish the current geographical range of T. annae infection.
在西班牙西北部，由泰勒虫引起的梨形虫病如今被视为一个严重问题，因为兽医尽管知晓梨形虫病的临床症状，但缺乏关于其流行病学的必要信息或针对该病的特定诊断工具。此外，泰勒虫感染对当前的梨形虫病治疗方法也具有抗性，这促使开展了本研究，旨在评估这种在很大程度上尚不为人知的犬类寄生虫病的临床表现和诊断方法。
对西班牙西北部临床上怀疑患有梨形虫病的120只犬进行检查，并通过对吉姆萨染色血涂片进行光学显微镜（LM）观察、免疫荧光抗体试验（IFAT）以及聚合酶链反应（PCR）加测序来检测梨形虫种类。
通过PCR确认75只患病犬感染了泰勒虫（称为“真正感染病例”）。在120份血样中的59份（其中57份为真正感染）中，通过光学显微镜观察到与小型梨形虫形态相符的红细胞内环形体。在120份血清中的59份（其中55份为“真正感染”）中通过IFAT检测到抗巴贝斯虫抗体。以PCR作为参考方法，在LM与PCR的阳性结果以及IFAT与PCR的阳性结果之间观察到中等程度的一致性（kappa值分别为0.6680和0.6017）。显微镜检查和IFAT在检测病原体方面具有中等敏感性（分别为76%和73.3%）。在75例“真正感染”病例中，观察到的最常见临床症状为黏膜苍白、厌食和冷漠。血细胞计数始终显示，由泰勒虫引起梨形虫病的犬存在严重的再生性贫血和血小板减少。幼犬（≤3岁）（p = 0.0001）对该病更易感。
显微镜检查对急性泰勒虫感染显示出中等诊断敏感性，而IFAT测定的抗体滴度较低（1/64至1/128）。因此，感染种类应通过分子检测来确认。我们的结果表明，该病影响西班牙与地方病流行的加利西亚地区接壤的未报告过这种梨形虫的地区的犬（西班牙北部的阿斯图里亚斯）。需要基于血清学和分子方法进行进一步的流行病学调查，以确定泰勒虫感染目前的地理范围。
