Department of Veterinary Medicine, National Taiwan University, 1 Sec 4 Roosevelt Rd, Taipei, 106216, Taiwan, Republic of China.
Graduate Institute of Molecular and Comparative Pathobiology, National Taiwan University, 1 Sec 4 Roosevelt Rd, Taipei, 106216, Taiwan, Republic of China.
BMC Vet Res. 2022 Sep 6;18(1):335. doi: 10.1186/s12917-022-03425-y.
Toxoplasma is an obligate intracellular protozoan that causes an important zoonotic disease with a worldwide distribution. Felids are the definitive hosts of this parasite, while virtually all warm-blooded animals, including birds, serve as intermediate hosts. Four ring-tailed lemurs (Lemur catta) in the Taipei Zoo died of acute Toxoplasma infection in June 2019. Since then, Toxoplasma has occasionally been identified in this Zoo during necropsy of dead animals and PCR of animal blood samples. Therefore, a general survey of Toxoplasma infection in animals in the Zoo seems to be needed.
An indirect multispecies ELISA was used for the first time to screen for Toxoplasma infection in 326 serum samples collected from 75 species of animals. The infection rate of Toxoplasma was 27% (88/326). A commercial latex agglutination (LAT) assay was used to re-examine the samples with doubtful and uncertain ELISA results (151 samples from 42 species). The infection rate increased to 36.2% (118/326), and the indirect multispecies ELISA appeared to be applicable to 31 of 75 species animals included in this study. Nested PCR assays targeting the dense granule protein 7 (GRA7) gene and B1 gene were also used to detect Toxoplasma in DNA samples extracted from 10 liver or blood specimens from 8 animals. GRA7 gene fragments were amplified from 8 samples from 7 animals, while B1 gene fragments were amplified from only 4 samples from 4 animals. From the B1 nested PCR and the sequence data of GRA7 fragments amplified from infectious specimens, the animals in the Zoo were speculated to have been infected by at least three different Toxoplasma variants.
According to the serological investigation, we speculated that over one-third (36.2%) of animals in Taipei Zoo presented the infection of Toxoplasma, and the indirect multispecies ELISA we used can be applied to detect Toxoplasma infection in 31 animal species included in this study. Sequence analysis revealed that at least three Toxoplasma variants were infecting the animals of Taipei Zoo.
弓形虫是一种专性细胞内原生动物，可引起一种具有全球分布的重要人畜共患疾病。猫科动物是该寄生虫的终末宿主，而几乎所有温血动物，包括鸟类，都是中间宿主。2019 年 6 月，台北动物园的四只环尾狐猴因急性弓形虫感染死亡。此后，在对动物园死亡动物的剖检和动物血液样本的 PCR 检测中，偶尔会发现弓形虫。因此，似乎需要对动物园内动物的弓形虫感染进行全面调查。
我们首次使用间接多物种 ELISA 检测了 326 份来自 75 种动物的血清样本，以筛查弓形虫感染。弓形虫的感染率为 27%（88/326）。使用商业乳胶凝集（LAT）检测对 ELISA 结果可疑和不确定的 151 份样本（来自 42 种动物）进行了重新检测。感染率上升至 36.2%（118/326），间接多物种 ELISA 似乎适用于本研究中包含的 75 种动物中的 31 种。还使用针对致密颗粒蛋白 7（GRA7）基因和 B1 基因的巢式 PCR 检测从 8 只动物的 10 份肝或血样中提取的 DNA 样本中的弓形虫。从 7 只动物的 8 份样本中扩增出 GRA7 基因片段，而仅从 4 只动物的 4 份样本中扩增出 B1 基因片段。从 B1 巢式 PCR 和从感染标本中扩增的 GRA7 片段的序列数据推断，动物园中的动物可能感染了至少三种不同的弓形虫变体。
根据血清学调查，我们推测台北动物园超过三分之一（36.2%）的动物存在弓形虫感染，我们使用的间接多物种 ELISA 可用于检测本研究中包含的 31 种动物物种的弓形虫感染。序列分析显示，至少有三种弓形虫变体感染了台北动物园的动物。
