**2. Epidemics of FMD in Korea**

Since 2000, Korea has experienced seven epidemics of FMD: March–April 2000, May–June 2002, January 2010, April–May 2010, November 2010–April 2011, July–August 2014, and December 2014–April 2015 [**Table 1** and **Figure 1**].


Epidemiology and Investigation of Foot‐and‐Mouth Disease (FMD) in the Republic of Korea http://dx.doi.org/10.5772/63975 5


**Table 1.** Epidemics of FMD in Korea from 2000 to 2015.

rized. RNA viruses show frequent spontaneous mutation, which results in emergence of new lineages. Phylogenetic analysis allows tracking the evolution and the origin of strains [1].

4 Epidemiology of Communicable and Non-Communicable Diseases - Attributes of Lifestyle and Nature on Humankind

Clinical signs of FMD are characterized by vesicles in foot, mouth, and teats. Virus starts excreting 2 days before the appearance of clinical signs (4 days in case of milk), and antibody can be detected from 3‐5 days after the appearance of clinical signs. High levels of antibodies are reached 2–4 days later and remained for many months. The virus disappears upon the appearance of antibody in most parts of the body. However, it continues to be detected exceptionally in laryngo‐pharyngeal fluid. Antibodies to FMD virus are directed against structural proteins (SP) in the viral capsid and non‐structural proteins (NSP) in the process of virus replication. SP antibodies are relatively serotype specific and induced by both vaccination and infection. Meanwhile, NSP antibodies are not serotype specific and induced by infection but rarely by non‐purified vaccine also. SP antibodies usually start to appear approximately 3–4 days after the appearance of clinical signs, while 6–7 days in case of NSP antibodies [2, 3].

FMD occurs throughout the world, mainly in countries of Asia, Africa and parts of South America. It is the first disease for which the OIE (World Organisation for Animal Health) established an official list of free countries upon the science‐based standards, guidelines and recommendations [4]. The Republic of Korea had been free from FMD without vaccination for the past 66 years, before a the outbreak of FMD in March 2000. In this chapter, epidemics of FMD in Korea from 2000 to 2015 are described together with their epidemiological character‐

Since 2000, Korea has experienced seven epidemics of FMD: March–April 2000, May–June 2002, January 2010, April–May 2010, November 2010–April 2011, July–August 2014, and

> **April (Ganghwa)**

4.8–5.6 (29 days)

15 16 6 11 153 3 185

4 counties in 4 provinces **November (Andong)**

'10.11.28 –'11.4.21 (145 days)

75 counties in 11 provinces **July (Euseong)**

7.23–8.6 (15 days)

3 counties in 2 provinces **December (Jincheon)**

'14.12.3 –'15.4.28 (147 days)

33 counties in 7 provinces

**2000 2002 2010 2014**

**January (Pocheon)**

1.2–1.29 (28 days)

2 counties in 1 province

istics.

**Year Month (Index region)**

Epidemic period

Number of outbreaks

Regions affected

**2. Epidemics of FMD in Korea**

3.24–4.15 (23 days)

6 counties in 3 provinces

December 2014–April 2015 [**Table 1** and **Figure 1**].

5.2–6.23 (53 days)

4 counties in 2 provinces

**Figure 1.** Distribution of outbreak farms of FMD in Korea from 2000 to 2015.

#### **2.1. Epidemic in 2000**

A suspected case was first reported from a dairy cattle farm in Paju, Gyeonggi‐do, on 20 March 2000. Serotype O FMD virus was identified, which included in the Pan‐Asian topotype. The route of virus introduction into Korea remains unclear. Fifteen outbreaks were reported until 15 April 2000. The outbreaks were concentrated in six counties of three provinces. There was one outbreak per county with the exception of one county, Hongseong, Chungcheongnam‐do, from which 10 outbreaks were reported. All of the outbreaks in this epidemic involved cattle farm. A total of 2,216 cloven‐hoofed animals of 182 farms were destroyed including all infected and neighbor farms within 500 m radius. Emergency vaccination (double‐oil emulsion vaccines containing inactivated FMD virus strain O1 Manisa) of all susceptible animals within 3 km of radius of outbreak farms was performed. During the first round, 860,700 animals and 661,770 for the second booster round had been vaccinated by August 2000. All vaccinated animals except for soon to be slaughtered finishing pigs were indicated with ear marking either by punching holes (pigs) or by branding (cattle, goat, and deer). The animals have been registered and maintained by county offices to be directly transferred to designated slaugh‐ terhouses. Between first and second round of vaccinations, a total of 198,930 animals have been either slaughtered through a government buying out program or sent to the designated slaughterhouses. In the vaccinated zones, clinical inspections by field veterinarians as well as statistically designed serological surveillance were performed [5]. The country regained the previous status of FMD free country without vaccination from the OIE in September 2001.

#### **2.2. Epidemic in 2002**

On 2 May 2002, a suspect case with vesicles on the nose, tongue, hoof and teat, deletion of hooves, and high mortality in piglets was reported at a pig farm located in Anseong, Gyeonggi‐ do. The second case was reported the next day at a pig farm in Jincheon, Chungcheongbuk‐ do. Serotype O FMD was confirmed on a total of 16 farms (15 pig farms and one cattle farm). It was concluded that the use of vaccines was not advisable for this epidemic. The following facts explain the reasons: The outbreaks were in intensive pig farming areas and some surrounding farms would already likely be infected; period required for pigs to gain immunity is 2–3 weeks, during which they would still be vulnerable to infection; the use of vaccination would prolong the required period to regain FMD free status; there was a risk of spread by vaccination teams; and vaccination would hinder the effectiveness of surveillance, making it difficult to detect any new FMD cases. Most of all, the epidemic was not spreading out of control [6].

#### **2.3. Epidemic in January 2010**

A private veterinarian notified early symptoms indicative of FMD such as loss of appetite and hyper‐salivation on a dairy cattle farm in Pocheon, Gyeonggi‐do, on 2 January 2010. Local veterinary service visited the farm, but lack of FMD‐specific lesions at that time interfered a proper sampling for laboratory test. The farm was placed under close observation. On 6 January, FMD‐specific lesions including erosion and ulcer in oral cavity and nasal passage, as well as ulcer and crust on teats, were observed. FMD virus serotype A was confirmed. All of

six cases in cattle farm in this epidemic were detected within 3.8 km radius from the first outbreak farm [7].

#### **2.4. Epidemic in April to May 2010**

**2.1. Epidemic in 2000**

**2.2. Epidemic in 2002**

**2.3. Epidemic in January 2010**

[6].

A suspected case was first reported from a dairy cattle farm in Paju, Gyeonggi‐do, on 20 March 2000. Serotype O FMD virus was identified, which included in the Pan‐Asian topotype. The route of virus introduction into Korea remains unclear. Fifteen outbreaks were reported until 15 April 2000. The outbreaks were concentrated in six counties of three provinces. There was one outbreak per county with the exception of one county, Hongseong, Chungcheongnam‐do, from which 10 outbreaks were reported. All of the outbreaks in this epidemic involved cattle farm. A total of 2,216 cloven‐hoofed animals of 182 farms were destroyed including all infected and neighbor farms within 500 m radius. Emergency vaccination (double‐oil emulsion vaccines containing inactivated FMD virus strain O1 Manisa) of all susceptible animals within 3 km of radius of outbreak farms was performed. During the first round, 860,700 animals and 661,770 for the second booster round had been vaccinated by August 2000. All vaccinated animals except for soon to be slaughtered finishing pigs were indicated with ear marking either by punching holes (pigs) or by branding (cattle, goat, and deer). The animals have been registered and maintained by county offices to be directly transferred to designated slaugh‐ terhouses. Between first and second round of vaccinations, a total of 198,930 animals have been either slaughtered through a government buying out program or sent to the designated slaughterhouses. In the vaccinated zones, clinical inspections by field veterinarians as well as statistically designed serological surveillance were performed [5]. The country regained the previous status of FMD free country without vaccination from the OIE in September 2001.

6 Epidemiology of Communicable and Non-Communicable Diseases - Attributes of Lifestyle and Nature on Humankind

On 2 May 2002, a suspect case with vesicles on the nose, tongue, hoof and teat, deletion of hooves, and high mortality in piglets was reported at a pig farm located in Anseong, Gyeonggi‐ do. The second case was reported the next day at a pig farm in Jincheon, Chungcheongbuk‐ do. Serotype O FMD was confirmed on a total of 16 farms (15 pig farms and one cattle farm). It was concluded that the use of vaccines was not advisable for this epidemic. The following facts explain the reasons: The outbreaks were in intensive pig farming areas and some surrounding farms would already likely be infected; period required for pigs to gain immunity is 2–3 weeks, during which they would still be vulnerable to infection; the use of vaccination would prolong the required period to regain FMD free status; there was a risk of spread by vaccination teams; and vaccination would hinder the effectiveness of surveillance, making it difficult to detect any new FMD cases. Most of all, the epidemic was not spreading out of control

A private veterinarian notified early symptoms indicative of FMD such as loss of appetite and hyper‐salivation on a dairy cattle farm in Pocheon, Gyeonggi‐do, on 2 January 2010. Local veterinary service visited the farm, but lack of FMD‐specific lesions at that time interfered a proper sampling for laboratory test. The farm was placed under close observation. On 6 January, FMD‐specific lesions including erosion and ulcer in oral cavity and nasal passage, as well as ulcer and crust on teats, were observed. FMD virus serotype A was confirmed. All of An outbreak of FMD serotype O was confirmed on April 9, following the previous day's notification of vesicles in the mouth and teats from a Hanwoo (Korean native beef cattle) farm in Ganghwa county of Incheon metropolis. As the second to fifth outbreaks, all occurred in the adjacent area, control measures including preemptive culling for all susceptible livestock in the protection zones within 3 km, were focused to prevent further spread of FMD. Extensive disinfection was carried out passing through two bridges connecting the Ganghwa Island to the mainland. Despite these collective efforts, on 21 April, a suspected case was reported at a pig farm located 135 km away from the previous outbreak area. Additional two outbreaks occurred in the latter area, Cheongyang, Chungcheongnam‐do, by 6 May. Comparison of the VP1 region of FMD viruses isolated from the infected farms showed 99.68–100% homology, suggesting that all of 11 outbreaks were from a same origin [7].

#### **2.5. Epidemic in November 2010 to April 2011**

FMD occurred three times in 2010 (January, April, and November). The first case of the third epidemic was reported on 28 November 2010, from one of the five pig farms in a complex in Andong, Gyeongsangbuk‐do. When officers of national veterinary services arrived in the farm, approximately 700 dead piglets were piled up in the farm yard. They found out that FMD was already widespread in all five piggeries. The oldest lesion was observed at the innermost farm. Until 21 April 2011, for 145 days, FMD outbreaks were confirmed in 153 farms raising cattle, pigs, goats, or deer in 75 counties of 11 provinces. Serotype O SEA topotype (Mya‐98 lineage) was isolated. Phylogenetic analysis showed nucleotide differences more or less 1.0% among FMD virus of outbreak farms. In early December 2010, FMD broke out primarily on Hanwoo (Korean native beef cattle) farms around the index case in Andong. However, on 14 December, two pig farms in Yeoncheon and Yangju in northern Gyeonggi‐do, belonged to the same owner, also reported FMD suspected animals. The nationwide spread of FMD was imminent. The epidemic continued until April of the next year [8]. The status of an FMD‐free country with vaccination was recognized by the OIE on 27 May 2014, 3 years after the last cases of the epidemics in April 2011. The approval was obtained after the review of the report, submitted on October 2013, which verified the non‐circulation of FMD virus for more than a year based on a test of non‐structural protein (NSP) antibodies in vaccinated animals.

Implementation of a vaccine containing inactivated O1 Manisa strain (monovalent) was urgently implemented. Injections were first administered on 25 December 2010, to cattle near the outbreak areas. Vaccination of pigs was first implemented on 6 January 2011. The program was gradually extended, and all cattle and pigs in Korea were subject to injection from 15 January 2011. The second set of injections was started on 23 January in cattle and 3 February in pigs, respectively, and completed by 26 February. In the case of pigs, the outbreak decreased remarkably 3 weeks after primary vaccination, while in the case of cattle, it decreased after 2 weeks. From 3 March, additional vaccination was implemented to animals born without maternal antibodies because they were born before the beginning of vaccination, and pigs at 3–4 weeks before delivery. And deer and goats were also added to the vaccine object. Since September 2011, it was mandatory for all cloven‐hoofed animals to be implemented with trivalent (O, A, Asia 1) vaccination by 6‐month interval. Before nationwide vaccination, all animals in the outbreak farm were stamped out. However, after 27 January 2011, when the nationwide vaccination was successfully completed, only animals showing symptoms or a positive reaction were stamped out [8].

#### **2.6. Epidemic in July to August 2014**

On 23 July 2014, the suspected animals were reported from 1 pig farm with 1,500 animals in Euseong, Gyeongsangbuk‐do. The presence of FMD virus was confirmed in the next morning. Clinical signs appeared in unvaccinated animals in that farm. Subsequently, FMD was diagnosed in two more farms by 6 August 2014 [9].

#### **2.7. Epidemic in December 2014 to April 2015**

After 4 months, on 3 December 2014, a veterinarian of a farm with 15,884 animals in Jincheon, Chungcheongbuk‐do, observed vesicles and ataxia in 30 pigs and reported the same to the county office. FMD was confirmed on the next day. During the next 147 days, until 28 April 2015, 180 pig farms and 5 cattle farms were confirmed with FMD [9].
