Coupe Alicia, Howe Laryssa, Burrows Elizabeth, Sine Abigail, Pita Anthony, Velathanthiri Niluka, Vallée Emilie, Hayman David, Shapiro Karen, Roe Wendi D
Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand.
Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Private Bag 11-222, Palmerston North, 4442, New Zealand.
Parasitol Res. 2018 May;117(5):1453-1463. doi: 10.1007/s00436-018-5832-8. Epub 2018 Mar 17.
Pollution of marine ecosystems with the protozoan parasites Toxoplasma gondii, Cryptosporidium spp. and Giardia duodenalis can be studied using bivalve shellfish as biosentinels. Although evidence suggests that these parasites are present in New Zealand coastal waters, the extent of protozoal pollution has not been investigated. This study used optimised molecular methods to detect the presence of Cryptosporidium spp., G. duodenalis and T. gondii in commercially sourced green-lipped mussel (Perna canaliculus), an endemic species found throughout coastal New Zealand. A nested polymerase chain reaction was validated for detection of T. gondii DNA and applied to 104 commercially sourced mussels. Thirteen mussels were positive for T. gondii DNA with an estimated true prevalence of 16.4% using Bayesian statistics, and the presence of T. gondii in mussels was significantly associated with collection during the summer compared with that in the winter (P = 0.003). Consumption of contaminated shellfish may also pose a health risk for humans and marine wildlife. As only sporulated T. gondii oocysts can be infectious, a reverse transcriptase-polymerase chain reaction was used to confirm presence of a sporozoite-specific marker (SporoSAG), detected in four mussels. G. duodenalis assemblage B, known to be pathogenic in humans, was also discovered in 1% mussels, tested by polymerase chain reaction (n = 90). Cryptosporidium spp. was not detected in the sampled mussel haemolymph. Results suggest that New Zealand may have high levels of coastal contamination with T. gondii, particularly in summer months, and that naturally exposed mussels can ingest and retain sporulated oocysts, further establishing shellfish consumption as a health concern.
利用双壳贝类作为生物哨兵，可以研究海洋生态系统被原生动物寄生虫刚地弓形虫、隐孢子虫属和十二指肠贾第虫污染的情况。尽管有证据表明这些寄生虫存在于新西兰沿海水域，但原生动物污染的程度尚未得到调查。本研究采用优化的分子方法，检测在新西兰沿海广泛分布的本地物种——商业采购的绿唇贻贝（Perna canaliculus）中隐孢子虫属、十二指肠贾第虫和刚地弓形虫的存在情况。验证了一种巢式聚合酶链反应用于检测刚地弓形虫DNA，并将其应用于104个商业采购的贻贝。13个贻贝的刚地弓形虫DNA呈阳性，使用贝叶斯统计估计真实患病率为16.4%，与冬季相比，贻贝中刚地弓形虫的存在与夏季采集显著相关（P = 0.003）。食用受污染的贝类也可能对人类和海洋野生动物构成健康风险。由于只有孢子化的刚地弓形虫卵囊具有传染性，因此使用逆转录聚合酶链反应来确认在4个贻贝中检测到的子孢子特异性标记（SporoSAG）的存在。通过聚合酶链反应检测（n = 90），在1%的贻贝中还发现了已知对人类致病的十二指肠贾第虫B群。在所采集的贻贝血淋巴中未检测到隐孢子虫属。结果表明，新西兰沿海可能受到刚地弓形虫的高度污染，特别是在夏季月份，并且自然暴露的贻贝可以摄取并保留孢子化的卵囊，这进一步表明食用贝类是一个健康问题。
