中国黑龙江省绵羊和山羊中十二指肠贾第虫的遗传特征及可能的人畜传播。
Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission.
机构信息
Department of Parasitology, Harbin Medical University, Harbin, People's Republic of China.
出版信息
PLoS Negl Trop Dis. 2012;6(9):e1826. doi: 10.1371/journal.pntd.0001826. Epub 2012 Sep 20.
BACKGROUND
Giardia duodenalis is a widespread intestinal protozoan of both humans and mammals. To date, few epidemiological studies have assessed the potential and importance of zoonotic transmission; and the human giardiasis burden attributable to G. duodenalis of animal origin is unclear. No information about occurrence and genotyping data of sheep and goat giardiasis is available in China. The aim of the present study was to determine prevalence and distribution of G. duodenalis in sheep and goats in Heilongjiang Province, China, and to characterize G. duodenalis isolates and assess the possibility of zoonotic transmission.
METHODOLOGY/PRINCIPAL FINDINGS: A total of 678 fecal specimens were collected from sheep and goats on six farms ranging in age from one month to four years in Heilongjiang Province, China. The average prevalence of G. duodenalis infection was 5.0% (34/678) by microscopy after Lugol's iodine staining, with 5.6% (30/539) for the sheep versus 2.9% (4/139) for the goats. Molecular analysis was conducted on 34 G. duodenalis isolates based on the triosephosphate isomerase (tpi) gene. 29 tpi gene sequences were successfully obtained and identified as assemblages A (n = 4), B (n = 2) and E (n = 23). High heterogeneity was observed within assemblage E at the tpi locus, with five novel subtypes found out of seven subtypes. Two subtypes of assemblage A were detected, including subtype AI (n = 3) and a novel subtype (designated as subtype AIV) (n = 1). Two assemblage B isolates were identical to each other in the tpi gene sequences.
CONCLUSIONS/SIGNIFICANCE: This is the first report of G. duodenalis infections in sheep and goats in China. The present data revealed the unique endemicity on prevalence, distribution and genetic characterization of G. duodenalis in sheep and goats in Heilongjiang Province. The findings of assemblages A and B in sheep and goats implied the potential of zoonotic transmission.
背景
蓝氏贾第鞭毛虫是一种广泛存在于人类和哺乳动物肠道中的原生动物。迄今为止，很少有流行病学研究评估动物源传播的潜力和重要性；动物源性贾第鞭毛虫导致的人类贾第虫病负担尚不清楚。在中国，尚无有关绵羊和山羊贾第虫病的发生和基因分型数据的信息。本研究旨在确定中国黑龙江省绵羊和山羊中贾第虫的流行情况和分布情况，并对贾第虫分离株进行特征描述，评估其发生人畜共患传播的可能性。
方法/主要发现：从中国黑龙江省六个农场的 1 至 4 岁绵羊和山羊中采集了 678 份粪便样本。通过卢戈氏碘染色后显微镜检查，发现蓝氏贾第鞭毛虫的平均感染率为 5.0%（34/678），绵羊为 5.6%（30/539），山羊为 2.9%（4/139）。基于三磷酸甘油醛异构酶（tpi）基因对 34 个贾第虫分离株进行了分子分析。成功获得并鉴定了 29 个 tpi 基因序列，分为 A 组（n = 4）、B 组（n = 2）和 E 组（n = 23）。在 tpi 基因座内观察到 E 组内高度异质性，在 7 种亚型中发现了 5 种新型亚型。检测到 2 种 A 组亚型，包括 AI 亚型（n = 3）和一种新型亚型（命名为 AIV 亚型）（n = 1）。2 个 B 组分离株的 tpi 基因序列完全相同。
结论/意义：这是中国首次报道绵羊和山羊中存在蓝氏贾第鞭毛虫感染。本研究数据揭示了黑龙江省绵羊和山羊中贾第虫的流行情况、分布和遗传特征的独特地方性。在绵羊和山羊中发现的 A 组和 B 组提示存在人畜共患传播的潜在可能性。
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