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Parasit Vectors. 2017 Jul 25;10(1):351. doi: 10.1186/s13071-017-2285-3.

Distribution and current infection status of Biomphalaria straminea in Hong Kong.

Author information

1
School of Life Science, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, Special Administrative Region, People's Republic of China.
2
Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, People's Republic of China.
3
Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, Guangdong Province, People's Republic of China.
4
Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
5
Department of Biology, Hong Kong Baptist University, Hong Kong, Special Administrative Region, People's Republic of China.
6
Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong Province, People's Republic of China. wuzhd@mail.sysu.edu.cn.
7
Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, Guangdong Province, People's Republic of China. wuzhd@mail.sysu.edu.cn.
8
School of Life Science, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, Special Administrative Region, People's Republic of China. jeromehui@cuhk.edu.hk.

Abstract

BACKGROUND:

Schistosomiasis, also generally known as snail fever, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. In Hong Kong and mainland China, the freshwater snail Biomphalaria straminea has been introduced and has the potential to transmit intestinal schistosomiasis caused by S. mansoni, a parasite of man which has a wide distribution in Africa and parts of the New World, especially Brazil. The first identification of B. straminea in Hong Kong dates back to the 1970s, and its geographical distribution, phylogenetic relationships, and infection status have not been updated for more than 30 years. Thus, this study aims to reveal the distribution and current infection status of B. straminea in contemporary Hong Kong.

METHODS:

Snails were collected from different parts of Hong Kong from July 2016 to January 2017. Both anatomical and molecular methods were applied to identify B. straminea. Cytochrome c oxidase subunit 1 (cox1), internal transcribed spacer 1 (ITS1), 5.8S rDNA, internal transcribed spacer 2 (ITS2), and 16S ribosomal DNA (rDNA) were sequenced from individual snails and analyzed. To detect the presence of S. mansoni, both biopsy and PCR analyses were carried out.

RESULTS:

Using both anatomical and molecular analyses, this study demonstrated the existence of black- and red-coloured shell B. straminea in different districts in the New Territories in Hong Kong, including places close to the mainland China border. None of the B. straminea (n = 87) investigated were found to be infected with S. mansoni when tested by biopsy and PCR. The Hong Kong B. straminea are genetically indistinguishable, based on the chosen molecular markers (cox1, ITS1-5.8S-ITS2, and 16S rDNA), and are similar to those obtained in mainland China and South America.

CONCLUSION:

Biomphalaria straminea is now well established in freshwater habitats in Hong Kong. No evidence of infection with S. mansoni has been found. Surveillance should be continued to monitor and better understand this schistosomiasis intermediate host in mainland China and Hong Kong.

KEYWORDS:

Biomphalaria straminea; China; Hong Kong; Schistosoma mansoni; Schistosomiasis

PMID:
28743308
PMCID:
PMC5526268
DOI:
10.1186/s13071-017-2285-3
[Indexed for MEDLINE]
Free PMC Article

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