Kjemtrup Anne M, Conrad Patricia A
California Department of Health Services, Vector-Borne Disease Section, 1616 Capital Avenue, MS 7307, Sacramento, CA 95899-7413, USA.
Vet Parasitol. 2006 May 31;138(1-2):112-7. doi: 10.1016/j.vetpar.2006.01.045. Epub 2006 Mar 7.
Small piroplasms as a cause of canine babesiosis in southern California were first documented in 1990. Initially these piroplasms were considered to be Babesia gibsoni, the only small Babesia parasite known to infect dogs at that time. In the following decade, the use of molecular analysis made it clear that small canine Babesia in fact are comprised of at least three distinct species, and the isolates from dogs in southern California were not B. gibsoni. Molecular, antigenic, and morphological characteristics of the southern California species of canine piroplasm supported naming it as a distinct species, Babesia conradae. The renaming of this species prompted this literature review of small canine piroplasms in California in order to clarify clinical, diagnostic, epidemiological, and molecular characteristics of B. conradae in comparison to other small canine piroplasms. Clinical symptoms of B. conradae are similar to those of B. gibsoni; however, B. conradae infections may be more pathogenic, resulting in higher parasitaemia and more pronounced anaemia when compared with B. gibsoni-infected dogs. The immunofluorescent antibody test is the most commonly used test to diagnose B. conradae. It is important to specify which small Babesia species to test for since there is little serological cross reactivity between the small canine Babesia antigens or cross-detection in the newer molecular tests. Molecular characterization of B. conradae, based principally on the 18S small subunit rRNA gene, and recently the second internal transcribed spacer region, demonstrate that B. conradae is most closely related to piroplasms recovered from humans and animals in the western United States.
小梨浆虫作为南加州犬巴贝斯虫病的病因首次记录于1990年。最初，这些梨浆虫被认为是吉氏巴贝斯虫，这是当时已知的唯一可感染犬类的小型巴贝斯虫寄生虫。在接下来的十年里，分子分析表明，小型犬巴贝斯虫实际上至少由三个不同的物种组成，南加州犬类分离出的菌株并非吉氏巴贝斯虫。南加州犬梨浆虫物种的分子、抗原和形态学特征支持将其命名为一个独特的物种，即康氏巴贝斯虫。该物种的重新命名促使对加利福尼亚州小型犬梨浆虫进行文献综述，以阐明康氏巴贝斯虫与其他小型犬梨浆虫相比的临床、诊断、流行病学和分子特征。康氏巴贝斯虫的临床症状与吉氏巴贝斯虫相似；然而，与感染吉氏巴贝斯虫的犬相比，感染康氏巴贝斯虫可能更具致病性，导致更高的寄生虫血症和更明显的贫血。免疫荧光抗体试验是诊断康氏巴贝斯虫最常用的试验。由于小型犬巴贝斯虫抗原之间几乎没有血清学交叉反应，或者在更新的分子试验中没有交叉检测，因此明确检测哪种小型巴贝斯虫物种很重要。主要基于18S小亚基rRNA基因以及最近的第二个内部转录间隔区对康氏巴贝斯虫进行的分子特征分析表明，康氏巴贝斯虫与从美国西部的人和动物体内分离出的梨浆虫关系最为密切。
