Printer Friendly

Reemergence of foot-and-mouth disease, South Korea, 2000-2011.

Foot-and-mouth disease is an infectious viral disease that occurs in animals and is easily transmissible. Outbreaks of this disease affect international trade (1). Since 2000, five outbreaks (in March 2000, May 2002, January 2010, April 2010, and November 2010-April 2011) have occurred in South Korea; the outbreak in 2000 was the first in 66 years (2-8).

To better understand the risks associated with reemergence of this disease in South Korea, we examined characteristics of these outbreaks and those occurring in neighboring countries by using macroscopic analysis. We describe the outbreak patterns to enable prediction and prevention of this disease in South Korea.

The Study

Spatiotemporal analyses used data obtained from the World Organisation for Animal Health Information Database (http://www.oie.int), the Food and Agriculture Organization World Reference Laboratory for foot-and-mouth disease (http://www.wrlfmd.org), the Southeast Asia and China Foot-and-Mouth Disease Campaign (http://www.seafmd-rcu.oie.int), national reports for international meetings (Southeast Asia and China Foot-and-Mouth Disease Campaign 2013, World Organisation for Animal Health/ Japan Trust Fund on foot-and-mouth disease control in Asia 2013), and previously reported data (9-11) for Southeast Asia (Vietnam, Cambodia, Myanmar, Thailand, Laos, Malaysia, and the Philippines) and eastern Asia (South Korea, Japan, China, Mongolia, Russia, North Korea, Hong Kong, and Taiwan) regions for 1999-2013. Statistical analysis was performed by using paired or unpaired f-tests, and correlation were made by using GraphPad InStat version 3.05 (Graph Pad Software, La Jolla, CA, USA). A phylogenetic tree was inferred by using the neighbor-joining method, and analysis was conducted by using MEGA version 6 (http://www.megasoftware.net/).

Comparative analysis of outbreaks in neighboring countries over the past 15 years showed a high incidence of outbreaks at 2- to 5-year intervals (2000, 2005, 2010-2011, and 2013) (Figure 1, panels A and F, http://wwwnc.cdc.gov/EID/article/20/12/13-0518-F1.htm). Analysis of outbreak serotypes and cases in neighboring countries (Figure 1, panels A-C) showed that type O foot-and-mouth disease virus has been predominant every year for the past 15 years. Outbreaks in eastern Asia and South Korea over the past 15 years showed a strong relationship with each other (r = 0.725) (Figure 1, panels D-H). Given the overall trend in Asia, serotype Asia 1 was predominant in 2005 (Figure 1, panels A, B). The situation for foot-and-mouth disease in Asia was regarded as serious during 2010-2011 because of the increased numbers of outbreaks (Figure 1, panels A, C-F). In 2013, the number of type A outbreaks increased, and outbreaks caused by types O and A viruses were still considered a threat (Figure 1, panels A, B).

Of 5 outbreaks in South Korea during 2000-2011, 4 were caused by type O virus, 2 were caused by the Middle East-South Asia topotype, and 2 were caused by the Southeast Asia topotype. One of the 5 outbreaks was caused by type A virus (ASIA topotype, Sea-97 lineage) (Table; Figure 1, panel I). Middle East-South Asia topotype viruses that caused outbreaks in 2000 and 2002 were related to PanAsia lineage viruses, which were detected during 19992000 in China, Taiwan, Japan, and Thailand; the causative viruses had high genetic similarity (12). We assume that these viruses, which have predominated in these regions since 1998 (12), were introduced to South Korea in 2000 and 2002. Serotype O viruses that caused outbreaks in 2010 were identified as SEA type, Mya-98 lineage. This virus type was detected in 2010 in Asia, including Russia, Japan, China, Hong Kong, and Vietnam, and the genetic similarity of these viruses was high (Figure 1, panel I). Type A virus (ASIA topotype, Sea-97 lineage) was detected in South Korea in January 2010. This virus is similar to those detected in 2009 in China and Vietnam. Genetic analyses of all viruses detected in South Korea showed a correlation with viruses that predominated in neighboring countries (Figure 1, panel I).

Major putative factors for inter-regional or inter-farm virus transmission during the 5 foot-and-mouth disease outbreaks in South Korea were movement of humans or vehicles (Table). The 5 outbreaks that occurred since 2000 were analyzed by province (Figure 2, panel A). The disease occurred most frequently in Gyeonggi Province (5 times), followed by Chungbuk Province (4 times) and Chungnam Province (3 times). Therefore, these 3 provinces, which had the highest risk for infection, were characterized by a high density of pig and cattle farms. On the basis of analysis of 4 outbreaks, the second round of outbreaks occurred 8.0 [+ or -] 2.0 days after the first infected group had been identified (Figure 2, panel B). In the most recent outbreak in November 2010, the initial diagnosis was delayed for 1 week; many concurrent infections were detected, and no unique aspects of transmission after the first detection of the disease had been identified (Figure 2, panel B). Most infections occurred [less than or equal to] 25 days after the initial case, after which occurrence was intermittent (Figure 2, panel B).

Conclusions

International trade and globalization have recently been indicated as major factors for transmission of infectious diseases associated with livestock (6). Multiple sources of serotypes O, A, and Asia 1 of foot-and-mouth disease viruses, which have caused recent outbreaks in eastern Asia, are endemic to Southeast Asia (13). Incursion of these viruses from Southeast Asia into eastern Asia has been suggested because of the porous nature of borders (13). However, the Korean Peninsula is surrounded by water on 3 sides and shares its only land border with North Korea. We believe that inflow of illegal live animals and livestock products, which is generally the highest risk factor for foot-and-mouth disease (14), is negligible in the regions around South Korea. Access to suspected infectious materials from countries with outbreaks is fundamentally blocked by shipping regulations.

Although no evidence for confirmation of introduction is available, results of epidemiologic investigations have indicated that the 5 foot-and-mouth disease outbreaks in South Korea were related primarily to indirect transmission by humans who came into contact with suspected infectious animals or livestock products from countries in Asia to which the virus is endemic (Table) (2-7). In addition, imported hay or other imported animal products were probable sources of virus in March 2000 and January 2010 (Table) (2,4,8), and the viruses were transmitted to persons who had contact with these materials directly or indirectly. On the basis of the national mandatory reporting system for foreign workers (http://www.kahis.go.kr), we found that the number of persons from Vietnam, Cambodia, Thailand, and China who work on farms in South Korea has been increasing since 2005. The recent situation can be regarded as conducive for an increased risk for foot-and-mouth disease.

The outbreak pattern of foot-and-mouth disease in South Korea was more strongly correlated with outbreaks in countries in eastern Asia than with outbreaks in Southeast Asia. Outbreaks every 15 years caused by type O foot-and-mouth disease virus are predominant in Asia. The greatest risk for infection is currently by type O and A viruses, followed by type Asia 1 virus.

In summary, type O foot-and-mouth disease virus was responsible for 4 outbreaks in South Korea and type A virus accounted for 1 outbreak. South Korea might be at risk for foot-and mouth disease, given the high incidence of this disease at 2- to 5-year intervals (2000, 2005, 20102011, and 2013) in eastern Asia. Foot-and-mouth disease outbreaks in neighboring countries were a probable major source of introduction of this disease into South Korea. Once this disease is introduced, prevention of domestic transmission should include extensive restriction of movement of humans or vehicles during an outbreak.

Acknowledgments

We thank the staff of the Animal and Plant Quarantine Agency for providing assistance during the study.

This study was supported by a grant from the Animal and Plant Quarantine Agency National Animal Disease Research Project.

Dr Park is a research scientist at the Animal and Plant Quarantine Agency, Gyeonggi-do, South Korea. His research interests are diagnosis and surveillance of foot and mouth disease, and development of vaccines and antiviral agents against this disease.

References

(1.) Callis JJ. Evaluation of the presence and risk of foot and mouth disease virus by commodity in international trade. Rev Sci Tech. 1996;15:1075-85.

(2.) Sakamoto K, Yoshida K. Recent outbreaks of foot and mouth disease in countries of east Asia. Rev Sci Tech. 2002;21:459-63.

(3.) Wee SH, Yoon H, More SJ, Nam HM, Moon OK, Jung JM, et al. Epidemiological characteristics of the 2002 outbreak of foot-and-mouth disease in the Republic of Korea. Transbound Emerg Dis. 2008;55:360-8. http://dx.doi.org/10.1111/j.18651682.2008.01045.x

(4.) Park JH, Lee KN, Ko YJ, Kim SM, Lee HS, Park JY, et al. Diagnosis and control measures of the 2010 outbreak of foot-and-mouth disease A type in the Republic of Korea. Transbound Emerg Dis. 2013;60:188-92. http://dx.doi.org/10.1111/j.1865-1682.2012.01333.x

(5.) Park JH, Lee KN, Ko YJ, Kim SM, Lee HS, Shin YK, et al. Control of foot-and-mouth disease during 2010-2011 epidemic, South Korea. Emerg Infect Dis. 2013;19:655-9. http://dx.doi.org/10.3201/eid1904.121320

(6.) Park JH, Lee KN, Ko YJ, Kim SM, Lee HS, Park JY, et al. Outbreaks and diagnosis of foot-and-mouth disease serotype O in the Republic of Korea, April-June 2010. Transbound Emerg Dis. 2014;61:27784. http://dx.doi.org/10.1111/tbed.12029

(7.) Yoon H, Yoon SS, Kim YJ, Moon OK, Wee SH, Joo YS, et al. Epidemiology of the foot-and-mouth disease serotype O epidemic of November 2010 to April 2011 in the Republic of Korea. Transbound Emerg Dis. 2013. [Epub ahead of print]. http://dx.doi.org/10.1111/tbed.12109

(8.) Shin JH, Sohn HJ, Choi KS, Kwon BJ, Ko YJ, An DJ, et al. Molecular epidemiological investigation of foot-and-mouth disease virus in Korea in 2000. J Vet Med Sci. 2003;65:9-16. http://dx.doi.org/10.1292/jvms.65.9

(9.) Di Nardo A, Knowles NJ, Paton DJ. Combining livestock trade patterns with phylogenetics to help understand the spread of foot and mouth disease in sub-Saharan Africa, the Middle East and Southeast Asia. Rev Sci Tech. 2011;30:63-85.

(10.) Valdazo-Gonzalez B, Timina A, Scherbakov A, Abdul-Hamid NF, Knowles NJ, King DP. Multiple introductions of serotype O footand-mouth disease viruses into east Asia in 2010-2011. Vet Res. 2013;44:76. http://dx.doi.org/10.1186/1297-9716-44-76

(11.) Madin B. An evaluation of foot-and-mouth disease outbreak reporting in mainland South-East Asia from 2000 to 2010. Prev Vet Med. 2011;102:230-41. http://dx.doi.org/10.1016/j.prevetmed.2011.07.010

(12.) Knowles NJ, Samuel AR, Davies PR, Midgley RJ, Valarcher JF. Pandemic strain of foot-and-mouth disease virus serotype O. Emerg Infect Dis. 2005;11:1887-93. http://dx.doi.org/10.3201/eid1112.050908

(13.) Knowles NJ, He J, Shang Y, Wadsworth J, Valdazo-Gonzalez B, Onosato H, et al. Southeast Asian foot-and-mouth disease viruses in eastern Asia. Emerg Infect Dis. 2012;18:499-501. http://dx.doi.org/10.3201/eid1803.110908

(14.) Pharo HJ. Foot-and-mouth disease: an assessment of the risks facing New Zealand. N Z Vet J. 2002;50:46-55. http://dx.doi.org/10.1080/00480169.2002.36250

Jong-Hyeon Park, Kwang-Nyeong Lee, Su-Mi Kim, Hyang-Sim Lee, Young-Joon Ko, Dong-Seob Tark, Yeun-Kyung Shin, Min-Goo Seo, and Byounghan Kim

Author affiliation: Animal and Plant Quarantine Agency, Gyeonggi-do, South Korea

DOI: http://dx.doi.org/10.3201/eid2012.130518

Address for correspondence: Jong-Hyeon Park, Animal and Plant Quarantine Agency, 175 Anyang-ro, Manan gu, Anyang City, Gyeonggido 430-757, South Korea; email: parkjhvet@korea.kr

Table. Characteristics of 5 outbreaks of foot-and mouth-disease,
South Korea, 2000-2011 *

Characteristic                     2000 Mar              2002 May

Disease status
  No. cases                           15                    16
  No. virus-positive cases            15                    16
  Duration virus detected,            22                    52
  d Period of virus              Mar 24-Apr 15         May 2-Jun 23
  detection

  Host tropism                     Ruminant            Pig (cattle)
  Serotype                             O             O (ME-SA/PanAsia)
  (topotype/lineage)            (ME-SA/PanAsia)
  No. affected provinces             3 (6)                 2 (4)
  (cities or counties)

  Economic losses, US$,               300                   143
  millions
  Date of disease-free            2001 Sep 16           2002 Nov 29
  status

Control measures
  Eradication policy               Culling,               Culling
                                  vaccination
  No. cattle culled                  2,021                 1,372
  No. pigs culled                     63                  158,708
  No. other animals culled            132                   75
  Total culled                       2,216                160,155
  Area of culling, km radius       0.5 (all)        0.5 (all), 3 (pigs)
  Vaccine strain                   O Manisa                 NA
  No. animals vaccinated         1st: 860,700,              NA
                               booster: 661,700

  Vaccination range,                  10                    NA
  km radius
  Serosurveillance area,              20                    10
  km radius

Restricted zones, km radius
  Management                          NA                    NA
  Surveillance                       10-20                 3-10
  Protection                         0-10                   0-3

Putative sources
  Regions in Asia as             Northeastern          Northeastern
  possible sources
  Major sources of first         International       Overseas travel,
  outbreak                        travelers,          foreign workers
                                 imported hay

  Low possibility sources      Windborne spread      Swill, saw dust,
  of first outbreak             of contaminated      wild animals and
                               yellow sand, wild    birds, yellow sand
                                     birds

  Possible transmission          Imported hay       Humans and vehicles
  factor for domestic
  regions

References ([dagger])                (2,8)                  (3)

Characteristic                     2010 Jan             2010 Apr

Disease status
  No. cases                            7                   13
  No. virus-positive cases             7                   29
  Duration virus detected,            28                   29
  d Period of virus              Jan 2-Jan 29          Apr 8-May 6
  detection

  Host tropism                     Ruminant           Ruminant, pig
  Serotype                      A (ASIA/SEA-97)      O (SEA/Mya-98)
  (topotype/lineage)
  No. affected provinces             1 (2)                4 (4)
  (cities or counties)

  Economic losses, US$,               29                   124
  millions
  Date of disease-free            2010 Sep 27          2010 Sep 27
  status

Control measures
  Eradication policy                Culling              Culling

  No. cattle culled                  2,905               10,858
  No. pigs culled                    2,953               38,274
  No. other animals culled            98                   742
  Total culled                       5,956               49,874
  Area of culling, km radius          0.5          0.5, 3 (on 2 farms)
  Vaccine strain                      NA                   NA
  No. animals vaccinated              NA                   NA

  Vaccination range,                  NA                   NA
  km radius
  Serosurveillance area,              10                   10
  km radius

Restricted zones, km radius
  Management                         10-20                10-20
  Surveillance                       3-10                 3-10
  Protection                          0-3                  0-3

Putative sources
  Regions in Asia as             Northeastern         Northeastern
  possible sources
  Major sources of first       Foreign workers,      Overseas travel
  outbreak                       international
                                    parcels

  Low possibility sources      Overseas travel,     Imported forage,
  of first outbreak            imported forage,         TMR feed
                                 tMr feed, saw
                                     dust

  Possible transmission             Humans          Vehicles, humans
  factor for domestic           (veterinarians,
  regions                      meetings, animal
                                   feeding)

References ([dagger])                 (4)                  (6)

                                   2010 Nov-
Characteristic                     2011 Apr

Disease status
  No. cases                           153
  No. virus-positive cases           3,700
  Duration virus detected,            145
  d Period of virus               Nov 28-2011
  detection                         Apr 21

  Host tropism                   Ruminant, pig
  Serotype                      O (SEA/Mya-98)
  (topotype/lineage)
  No. affected provinces            11 (75)
  (cities or counties)

  Economic losses, US$,              3,000
  millions
  Date of disease-free            2014 May 29
  status

Control measures
  Eradication policy               Culling,
                                  vaccination
  No. cattle culled                 150,864
  No. pigs culled                  3,318,298
  No. other animals culled          10,800
  Total culled                     3,479,962
  Area of culling, km radius          0.5
  Vaccine strain                   O Manisa
  No. animals vaccinated        All susceptible
                                    animals

  Vaccination range,              Nationwide
  km radius
  Serosurveillance area,              10
  km radius

Restricted zones, km radius
  Management                         10-20
  Surveillance                       3-10
  Protection                          0-3

Putative sources
  Regions in Asia as             Southeastern
  possible sources
  Major sources of first        Overseas travel
  outbreak

  Low possibility sources      Foreign workers,
  of first outbreak            illegal livestock
                                   products

  Possible transmission        Vehicles, humans
  factor for domestic
  regions

References ([dagger])                (5,7)

* ME-SA, Middle East-South Asia; USD, US dollars;
TMR, total mixed ration; NA, not applicable.

([dagger]) Data were obtained from national epidemiology investigation
reports on the 5 foot-and-mouth disease outbreaks in South Korea and
the references.
COPYRIGHT 2014 U.S. National Center for Infectious Diseases
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2014 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:DISPATCHES
Author:Park, Jong-Hyeon; Lee, Kwang-Nyeong; Kim, Su-Mi; Lee, Hyang-Sim; Ko, Young- Joon; Tark, Dong-Seob; S
Publication:Emerging Infectious Diseases
Geographic Code:90ASI
Date:Dec 1, 2014
Words:2566
Previous Article:Two outbreaks of Listeria monocytogenes infection, Northern Spain.
Next Article:Third strain of porcine epidemic diarrhea virus, United States.
Topics:

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters