Fayer R, Trout J M, Lewis E J, Xiao L, Lal A, Jenkins M C, Graczyk T K
Animal Waste Pathogen Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA.
Parasitol Res. 2002 Nov;88(11):998-1003. doi: 10.1007/s00436-002-0697-1. Epub 2002 Jul 17.
Although Cryptosporidium has been found worldwide in molluscan shellfish from waters contaminated with human and animal feces, little or no related environmental data have been obtained. In the present study, oysters ( Crassostrea virginica) were collected eight times over 3 years from seven sites in the Chesapeake Bay or its tributaries, with accompanying data on water temperature, salinity, rainfall, and streamflow. Oyster gill washings were examined by immunofluorescence microscopy for Cryptosporidium oocysts. Of 1,590 oysters collected, 19.6% had detectable oocysts. Of 53 collections, oocysts were detected 81% of the time. The time when the greatest percentage of oysters at most sites had detectable oocysts coincided with the time of greatest weekly and monthly rainfall, greatest streamflow into the Bay, and lowest water temperatures. In 28% of 53 collections, C. parvum genotypes 1 and 2 and C. baileyi were identified by PCR and gene sequencing. Oocyst infectivity was confirmed from 37.5% of 40 collections by initiating C. parvum genotype 2 infections in mice.
尽管隐孢子虫在全球范围内的受人类和动物粪便污染水域的软体贝类中均有发现，但相关环境数据却很少或几乎没有。在本研究中，3年内从切萨皮克湾及其支流的7个地点8次采集了牡蛎（弗吉尼亚牡蛎），并记录了水温、盐度、降雨量和流量等相关数据。通过免疫荧光显微镜检查牡蛎鳃冲洗液中的隐孢子虫卵囊。在采集的1590只牡蛎中，19.6%检测到卵囊。在53次采集样本中，81%的时间检测到卵囊。大多数地点检测到卵囊的牡蛎比例最高的时间，与每周和每月降雨量最大、流入海湾的流量最大以及水温最低的时间一致。在53次采集中，28%通过PCR和基因测序鉴定出微小隐孢子虫1型和2型以及贝氏隐孢子虫。通过在小鼠中引发微小隐孢子虫2型感染，在40次采集中的37.5%中确认了卵囊的感染性。
