Erlandsen S L, Sherlock L A, Bemrick W J, Ghobrial H, Jakubowski W
Department of Cell Biology & Neuroanatomy, University of Minnesota School of Medicine, Minneapolis 55455.
Appl Environ Microbiol. 1990 Jan;56(1):31-6. doi: 10.1128/aem.56.1.31-36.1990.
Surveys of the prevalence of the intestinal protozoan Giardia spp. in animal populations have relied almost exclusively on the detection of cysts in fecal samples. We have determined the prevalence of Giardia spp. in beaver and muskrat populations in four northeastern states and Minnesota by using both the detection of trophozoites in mucosal scrapings from live-trapped animals at necropsy and the detection of cysts in fecal samples collected from kill-trapped animals. In muskrats the prevalence of Giardia infection was 36.6% by cyst detection in fecal samples (n = 790) from kill-trapped animals and 95.9% in live-trapped muskrats when the intestinal contents were analyzed for the presence of trophozoites (n = 219). Similarly, in beavers, Giardia infection was 9.2% by cyst detection in fecal samples (n = 662) from kill-trapped beavers and 13.7% in live-trapped animals examined for the presence of intestinal trophozoites (n = 302). The detection of trophozoites in mucosal scrapings from live-trapped animals consistently yielded a significantly higher prevalence for both muskrats and beavers than did the method based on detection of cysts in the fecal samples. The prevalence of Giardia infection in juvenile and adult live-trapped muskrats was similar (92.5 and 94.4%, respectively), but the prevalence in juvenile live-trapped beavers (23.2%) was significantly greater than that seen in the adult animals (12.6%). No difference in Giardia prevalence on the basis of sex was seen in either animal species. Regional variation, often statistically significant, was seen in the prevalence of Giardia in beavers in the northeastern states and Minnesota, but was not detected for muskrats.
对动物群体中肠道原生动物贾第虫属（Giardia spp.）流行情况的调查几乎完全依赖于粪便样本中包囊的检测。我们通过在尸检时对活体诱捕动物的黏膜刮片进行滋养体检测以及对捕杀诱捕动物采集的粪便样本进行包囊检测，确定了美国东北部四个州和明尼苏达州海狸和麝鼠群体中贾第虫属的流行情况。在麝鼠中，通过对捕杀诱捕动物粪便样本（n = 790）进行包囊检测，贾第虫感染率为36.6%；而在对活体诱捕麝鼠（n = 219）的肠道内容物进行滋养体分析时，感染率为95.9%。同样，在海狸中，通过对捕杀诱捕海狸粪便样本（n = 662）进行包囊检测，贾第虫感染率为9.2%；在对活体诱捕动物进行肠道滋养体检测时，感染率为13.7%（n = 302）。对活体诱捕动物的黏膜刮片进行滋养体检测，麝鼠和海狸的感染率始终显著高于基于粪便样本包囊检测的方法。幼年和成年活体诱捕麝鼠的贾第虫感染率相似（分别为92.5%和94.4%），但幼年活体诱捕海狸的感染率（23.2%）显著高于成年动物（12.6%）。在这两种动物中，均未发现贾第虫感染率在性别上存在差异。在东北部各州和明尼苏达州的海狸中，贾第虫的流行情况存在区域差异，且差异通常具有统计学意义，但在麝鼠中未检测到这种差异。
