Limits...
Molecular and serological epidemiology of Japanese encephalitis virus (JEV) in a remote island of western Japan: an implication of JEV migration over the East China Sea.

Yoshikawa A, Nabeshima T, Inoue S, Agoh M, Morita K - Trop Med Health (2016)

Bottom Line: There were 47 JEV strains isolated in Nagasaki from 2001 to 2014 including the isolates in this study, and they belonged to genotype 1.In the subcluster 1-A-2, three different monophyletic subgroups, 1-A-2-2 (2010), 1-A-2-3 (2011), and 1-A-2-1 (2013, 2014), appeared in Goto.These data strongly suggested that JEV appearance in Goto seems to depend on the frequent introduction of JEV from outside of the island and this pattern is different from what has been observed in subtropical islands in the East China Sea such as Okinawa and Taiwan, where the same populations of JEV (1-A-7 (1998-2008) in Okinawa; genotype 3 (until 2012) in Taiwan) have been maintained for a long period.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan ; Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan ; Department of Public Health, Nagasaki Prefectural Institute for Environmental Research and Public Health, 2-1306-11 Ikeda, Omura, Nagasaki 856-0026 Japan.

ABSTRACT

Background: Japanese encephalitis (JE) is a mosquito-borne infectious disease caused by Japanese encephalitis virus (JEV). About 1-10 cases with severe central nervous system symptoms have been constantly reported every year in Japan. To clarify the mechanism of maintenance of JEV, the present study surveyed pigs for serological evidence of JEV infection and isolated JEV strains from pigs and mosquitoes in Isahaya City (Isahaya) and Goto City (Goto) in the islets of Goto in Nagasaki Prefecture from 2008 to 2014.

Results: The serological survey of pigs showed the increase of IgM sero-positivity against JEV in July or August, and it was maintained until October or November in both Isahaya and Goto every year. There were 47 JEV strains isolated in Nagasaki from 2001 to 2014 including the isolates in this study, and they belonged to genotype 1. Thirty four of the isolated strains were from pigs in Isahaya and were classified under six subclusters (1-A-1, 1-A-2, 1-A-3, 1-A-4, 1-A-5, and 1-A-9). Thirteen strains were isolated from pigs and mosquitoes in Goto and were classified into three subclusters (1-A-5 (2008); 1-A-1 (2009); and 1-A-2). In the subcluster 1-A-2, three different monophyletic subgroups, 1-A-2-2 (2010), 1-A-2-3 (2011), and 1-A-2-1 (2013, 2014), appeared in Goto.

Conclusions: These data strongly suggested that JEV appearance in Goto seems to depend on the frequent introduction of JEV from outside of the island and this pattern is different from what has been observed in subtropical islands in the East China Sea such as Okinawa and Taiwan, where the same populations of JEV (1-A-7 (1998-2008) in Okinawa; genotype 3 (until 2012) in Taiwan) have been maintained for a long period.

No MeSH data available.


Related in: MedlinePlus

Two observation points in Nagasaki Prefecture for monitoring of JEV. Pig serum samples and mosquitoes were collected in Isahaya and Goto which were indicated by black solid circles
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4940834&req=5

Fig1: Two observation points in Nagasaki Prefecture for monitoring of JEV. Pig serum samples and mosquitoes were collected in Isahaya and Goto which were indicated by black solid circles

Mentions: The present study aimed to clarify the ecology of JEV in Japan by two approaches: serological survey of swine sera and molecular epidemiological analysis of JEV isolates from pigs and mosquitoes collected in two observation points in Nagasaki Prefecture from 2008 to 2014. Goto City (Goto) in the islets of Goto was selected as an observation point because of its location—a small remote island in western Japan—and the presence of pig farms and wide rice paddy fields which are important factors for JEV maintenance cycle [16]. Another observation point was Isahaya City (Isahaya) located in Kyushu main island (Fig. 1). Many pig farms, wide rice paddy fields, and many wild boars exist in that area. The influence of the geographical uniqueness and environment of these two observation points for the maintenance of JEV was the major interest of this survey.Fig. 1


Molecular and serological epidemiology of Japanese encephalitis virus (JEV) in a remote island of western Japan: an implication of JEV migration over the East China Sea.

Yoshikawa A, Nabeshima T, Inoue S, Agoh M, Morita K - Trop Med Health (2016)

Two observation points in Nagasaki Prefecture for monitoring of JEV. Pig serum samples and mosquitoes were collected in Isahaya and Goto which were indicated by black solid circles
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4940834&req=5

Fig1: Two observation points in Nagasaki Prefecture for monitoring of JEV. Pig serum samples and mosquitoes were collected in Isahaya and Goto which were indicated by black solid circles
Mentions: The present study aimed to clarify the ecology of JEV in Japan by two approaches: serological survey of swine sera and molecular epidemiological analysis of JEV isolates from pigs and mosquitoes collected in two observation points in Nagasaki Prefecture from 2008 to 2014. Goto City (Goto) in the islets of Goto was selected as an observation point because of its location—a small remote island in western Japan—and the presence of pig farms and wide rice paddy fields which are important factors for JEV maintenance cycle [16]. Another observation point was Isahaya City (Isahaya) located in Kyushu main island (Fig. 1). Many pig farms, wide rice paddy fields, and many wild boars exist in that area. The influence of the geographical uniqueness and environment of these two observation points for the maintenance of JEV was the major interest of this survey.Fig. 1

Bottom Line: There were 47 JEV strains isolated in Nagasaki from 2001 to 2014 including the isolates in this study, and they belonged to genotype 1.In the subcluster 1-A-2, three different monophyletic subgroups, 1-A-2-2 (2010), 1-A-2-3 (2011), and 1-A-2-1 (2013, 2014), appeared in Goto.These data strongly suggested that JEV appearance in Goto seems to depend on the frequent introduction of JEV from outside of the island and this pattern is different from what has been observed in subtropical islands in the East China Sea such as Okinawa and Taiwan, where the same populations of JEV (1-A-7 (1998-2008) in Okinawa; genotype 3 (until 2012) in Taiwan) have been maintained for a long period.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan ; Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan ; Department of Public Health, Nagasaki Prefectural Institute for Environmental Research and Public Health, 2-1306-11 Ikeda, Omura, Nagasaki 856-0026 Japan.

ABSTRACT

Background: Japanese encephalitis (JE) is a mosquito-borne infectious disease caused by Japanese encephalitis virus (JEV). About 1-10 cases with severe central nervous system symptoms have been constantly reported every year in Japan. To clarify the mechanism of maintenance of JEV, the present study surveyed pigs for serological evidence of JEV infection and isolated JEV strains from pigs and mosquitoes in Isahaya City (Isahaya) and Goto City (Goto) in the islets of Goto in Nagasaki Prefecture from 2008 to 2014.

Results: The serological survey of pigs showed the increase of IgM sero-positivity against JEV in July or August, and it was maintained until October or November in both Isahaya and Goto every year. There were 47 JEV strains isolated in Nagasaki from 2001 to 2014 including the isolates in this study, and they belonged to genotype 1. Thirty four of the isolated strains were from pigs in Isahaya and were classified under six subclusters (1-A-1, 1-A-2, 1-A-3, 1-A-4, 1-A-5, and 1-A-9). Thirteen strains were isolated from pigs and mosquitoes in Goto and were classified into three subclusters (1-A-5 (2008); 1-A-1 (2009); and 1-A-2). In the subcluster 1-A-2, three different monophyletic subgroups, 1-A-2-2 (2010), 1-A-2-3 (2011), and 1-A-2-1 (2013, 2014), appeared in Goto.

Conclusions: These data strongly suggested that JEV appearance in Goto seems to depend on the frequent introduction of JEV from outside of the island and this pattern is different from what has been observed in subtropical islands in the East China Sea such as Okinawa and Taiwan, where the same populations of JEV (1-A-7 (1998-2008) in Okinawa; genotype 3 (until 2012) in Taiwan) have been maintained for a long period.

No MeSH data available.


Related in: MedlinePlus