RESEARCH ARTICLE


Imported Dogs as Possible Vehicles of Vibrio Cholerae O1 Causing Cholera Outbreaks in Northern Vietnam



Tuan Cuong Ngo1, Dong Tu Nguyen1, 2, Huy Hoang Tran1, Thanh Huong Le1, Hoai Thu Nguyen1, Tai The Diep3, Thi Phuong Lan Nguyen3, Binh Minh Nguyen1, Nhu DuongTran4, Tetsu Yamashiro5, Kouichi Morita2, Tran Hien Nguyen4, Masahiko Ehara*, 6
1 Department of Bacteriology, National Institute of Hygiene and Epidemiology, No.1 Yersin Street, Hanoi 10, 000, Vietnam
2 Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
3 Department of Microbiology and Immunology, Pasteur Institute, 167 Pasteur Street, 8 Ward, 3 District, Ho Chi Minh City, Vietnam
4 Department of Epidemiology, National Institute of Hygiene and Epidemiology, No.1 Yersin Street, Hanoi 10, 000, Vietnam
5 Vietnam Research Station, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
6 Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan


© 2011 Cuong Ngo et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Correspondence: * Address correspondence to this author at the Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.Tel: +81 95 819 7832; Fax: +81 95 819 7805; E-mail: ehara@nagasaki-u.ac.jp


Abstract

Strains of V. cholerae O1 were isolated from the sewage and a pond near the first patient's house and also from domestic vegetables obtained at a neighboring market. From 24 October 2007 to 25 June 2009, 1,505 cases were confirmed positive for V. cholerae O1 (biotype El Tor, serotype Ogawa) in 22 cities and provinces in northern Vietnam. On May 8 and May 12, 2009, epidemic strains of V. cholerae O1 were isolated from dogs in slaughter houses in Hanoi and from dogs in cages in Thanh Hoa, respectively. Isolates of V. cholerae O1 in Laos and Thailand were found to be the same clone as those isolates from dogs, patients and environmental water samples in northern Vietnam. Although the transmission routes of cholera differed between the northern and southern provinces of Vietnam, the same clonality was observed among isolates from 2007 to 2010.

Keywords: Cholera, clonality, multiple drug resistance gene, tetA (class D)..