Racewicz Maria, Kruminis-Łozowska Wiesława, Gabre Refaat M, Stańczak Joanna
Zakad Parazytologii Tropikalnej, Miedzywydziałowy Instytut Medycyny Morskiej i Tropikalnej, Gdański Uniwersytet Medyczny, ul. Powstania Styczniowego 9B, 81-519 Gdynia.
Wiad Parazytol. 2009;55(3):231-6.
This study was carried out to determine the role of non-biting synanthropic flies as carriers of Cryptosporidium spp. oocysts in the vicinity of the city of Gdańsk (NE Poland). In 2001-2003, flies were collected from three breeding sites: cow sheds and meadows in the Bystra cattle farm and municipal landfill Szadółki using inhaustors (aspirators) and entomologic nets. A total of 2358 specimens of the families: Muscidae (n = 1598), Calliphoridae (n = 739) and Sarcophagidae (n =21) were collected and analysed in 249 pools consisted of 9.5 insects, in average. Microscopic examination was used to detect Cryptosporidium spp. oocysts in the fly faeces deposited on the glass microscope slides and stained by Zhiel-Nielsen method. The mean number of faecal droplets per one glass slide was 11.5. Ooocysts of Cryptosporidium spp., stained from light pink to bright red, were found in fly faeces deposited on 25 (27.5%) of 91 glass slides checked. The highest prevalence of the pathogen was observed in faecal droplets deposited by flies collected in municipal landfill (50% investigated slides). DNA of Cryptosporidium spp. was extracted from the surface eluants of flies and/or their gut homogenates and purified. Then extracts were examined by PCR using CPB-DIAGF and CPB-DIAGR primers amplifying a variable region SSU-rRNA of all Cryptosporidium species. Altogether 387 isolates, 228 from surfaces and 159 from gut homogenates, were obtained from 249 pools of flies and analyzed. A specific 435 bp fragment of DNA was obtained in 49 (12.7%) lysates tested. In 10.4% pools, DNA of the pathogen was detected only in the surface eluants while in 7.6% only in gut extracts. In the case of two pooled samples (0.8%) Cryptosporidium spp. was found in both types of lysates. In total, Cryptosporidium spp. was detected in 47/249 pools of flies (18.9%). Assumed that each positive pool contained just one infected fly, the percentage of specimens able to oocysts transmission were calculated at the minimal level 2.0% (n = 47/2358). The result confirm that synanthropic flies can harbour oocysts of Cryptosporidium spp. both externally and internally, and disseminate them mechanically in the environment. Therefore, under unsanitary conditions they could be involved in the transmission of human and animal cryptosporidiosis.
本研究旨在确定在格但斯克市（波兰东北部）附近，非吸血性共生蝇作为隐孢子虫属卵囊携带者的作用。在2001年至2003年期间，从三个繁殖地点收集苍蝇：比斯特拉奶牛场的牛棚和草地以及萨多乌基市垃圾填埋场，使用吸气器（捕虫器）和昆虫网进行收集。总共收集了2358只属于蝇科（n = 1598）、丽蝇科（n = 739）和麻蝇科（n = 21）的标本，并将其平均9.5只分为249组进行分析。通过显微镜检查来检测沉积在玻璃显微镜载玻片上并用齐尔-尼尔森法染色的苍蝇粪便中的隐孢子虫属卵囊。每张载玻片上粪便液滴的平均数为11.5。在检查的91张载玻片中，有25张（27.5%）上沉积的苍蝇粪便中发现了从浅粉色到鲜红色染色的隐孢子虫属卵囊。在市垃圾填埋场收集的苍蝇沉积的粪便液滴中观察到病原体的最高患病率（50%的调查载玻片）。从苍蝇的表面洗脱液和/或其肠道匀浆中提取并纯化隐孢子虫属的DNA。然后使用CPB-DIAGF和CPB-DIAGR引物通过PCR检查提取物，这些引物可扩增所有隐孢子虫物种的可变区域SSU-rRNA。从249组苍蝇中总共获得了387个分离株，其中228个来自表面，159个来自肠道匀浆，并进行了分析。在49个（12.7%）测试裂解物中获得了特定的435 bp DNA片段。在10.4%的组中，仅在表面洗脱液中检测到病原体的DNA，而在7.6%的组中仅在肠道提取物中检测到。在两个合并样本（0.8%）中，在两种类型的裂解物中都发现了隐孢子虫属。总共在47/249组苍蝇（18.9%）中检测到隐孢子虫属。假设每个阳性组仅包含一只受感染的苍蝇，能够传播卵囊的标本百分比计算为最低水平2.0%（n = 47/2358）。结果证实，共生蝇可以在外部和内部携带隐孢子虫属卵囊，并在环境中机械传播它们。因此，在不卫生的条件下，它们可能参与人和动物隐孢子虫病的传播。
