Brown G K, Canfield P J, Dunstan R H, Roberts T K, Martin A R, Brown C S, Irving R
Discipline of Biological Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan NSW 2308, Australia.
Aust Vet J. 2006 Sep;84(9):321-5. doi: 10.1111/j.1751-0813.2006.00029.x.
To detect Anaplasma platys and Babesia canis vogeli infection, using polymerase chain reaction (PCR)-based assays, in free-roaming dogs associated with eight Aboriginal communities in remote areas of Australia and to determine the impact of infection through the assessment of platelet numbers.
Blood samples from 215 dogs were screened by PCR for A platys and B canis vogeli using established genus-specific DNA primers for the 16S and 18S rRNA genes respectively. Both A platys DNA and B canis vogeli DNA were confirmed from the screening PCR either by sequencing or by the use of species-specific primers. Peripheral blood films from 92 of the 215 dogs were used to estimate platelet numbers through an indirect method.
Of 215 dogs, 69 (32%) were positive for A platys, 22 (10%) for B canis vogeli and 24 (11%) for both. The two organisms were detected singularly and as coinfection in all communities. For the 92 dogs in which peripheral blood films were examined, the mean estimated platelet counts for the non-infected dogs was 318 x 10(9)/L, those infected with A platys alone was 256 x 10(9)/L, those with B canis vogeli alone was 276 x 10(9)/L and those infected with both parasites was 169 x 10(9)/L. In young dogs, infection produced significantly decreased mean platelet counts when compared to uninfected dogs. Thrombocytopenia (< 200 x 10(9)/L) was detected in 18 (51%) dogs infected with A platys alone, 3 (33%) dogs infected with B canis vogeli alone, 13 (72%) dogs coinfected, and 8 (27%) uninfected dogs.
A platys and B canis vogeli infection, either singularly or together, was widespread in free roaming dogs associated with remote Aboriginal communities in the Northern Territory and north-western New South Wales. Moreover, both A platys and B canis vogeli infections were associated with a reduction in mean platelet numbers in dog populations, particularly in young dogs. The fact that 51% of dogs infected with A platys alone and 72% dogs coinfected were thrombocytopenic compared to 27% of uninfected dogs suggests that the organism alone or in combination with B canis vogeli has the potential to cause thrombocytopenia and perhaps contribute to a clinical bleeding disorder in infected dogs.
采用基于聚合酶链反应（PCR）的检测方法，检测澳大利亚偏远地区八个原住民社区自由放养犬中的血小板无形体和伯氏犬巴贝斯虫感染情况，并通过评估血小板数量来确定感染的影响。
分别使用针对16S和18S rRNA基因的既定属特异性DNA引物，通过PCR对215只犬的血样进行血小板无形体和伯氏犬巴贝斯虫的筛查。通过测序或使用种特异性引物，从筛查PCR中确认血小板无形体DNA和伯氏犬巴贝斯虫DNA。对215只犬中的92只犬的外周血涂片采用间接方法估计血小板数量。
在215只犬中，69只（32%）血小板无形体呈阳性，22只（10%）伯氏犬巴贝斯虫呈阳性，24只（11%）两种感染均呈阳性。在所有社区中均单独检测到这两种病原体，也检测到了混合感染情况。对于检查了外周血涂片的92只犬，未感染犬的平均估计血小板计数为318×10⁹/L，仅感染血小板无形体的犬为256×10⁹/L，仅感染伯氏犬巴贝斯虫的犬为276×10⁹/L，同时感染两种寄生虫的犬为169×10⁹/L。与未感染犬相比，幼犬感染后平均血小板计数显著降低。在仅感染血小板无形体的18只（51%）犬、仅感染伯氏犬巴贝斯虫的3只（33%）犬、混合感染的13只（72%）犬以及未感染的8只（27%）犬中检测到血小板减少症（<200×10⁹/L）。
血小板无形体和伯氏犬巴贝斯虫感染，无论是单独感染还是共同感染，在与北领地和新南威尔士州西北部偏远原住民社区相关的自由放养犬中广泛存在。此外，血小板无形体和伯氏犬巴贝斯虫感染均与犬群平均血小板数量减少有关，尤其是幼犬。与27%的未感染犬相比，仅感染血小板无形体的犬中有51%以及混合感染的犬中有72%出现血小板减少症，这表明该病原体单独或与伯氏犬巴贝斯虫共同感染有可能导致血小板减少症，或许还会引发感染犬的临床出血性疾病。
