CURRENT STATUS OF TRANSBOUNDARY ANIMAL DISEASES IN TAIWAN

Nein-Nung Lin1, and Shih-Tai Hwa1

1Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ), Council of Agriculture, Taipei, Taiwane-mail: niennong@mail.baphiq.gov.tw

ABSTRACT

The major Transboundary Animal Diseases (TADs) in Taiwan are Foot and Mouth Disease (FMD), and Highly Pathogenic Avian Influenza (HPAI). In the prevention and control of FMD, each cloven-hoofed animal should be vaccinated with FMD vaccines, and all farmers should follow the Regulation on FMD vaccination and farm biosecurity policy in Taiwan. The current FMD vaccination rate of cloven-hoofed animal farms has been above 90%. Above 80% of cloven-hoofed animal farms had herd level protection based on the results of serological surveillance in 2015. There is no FMD case detected or found in Taiwan, Penghu, and Matsu Island since June 2013, and in Kinmen Island since July 2015. Regarding HPAI in 2015, outbreaks of novel H5N2, H5N3 and H5N8 HPAI subtypes of Eurasia H5 clade 2.3.4.4 were reported in wild birds and domestic poultry in Taiwan. Six basic animal acids in their HA cleavage site, which have never been detected in Taiwan before and are approximately 98-99% identical to the H5 gene of the 2014 Korean H5N8 HPAIV. There is no evidence for these viruses to be zoonotic. In compliance with the no vaccination policy, 5,144,299 chickens, ducks, geese, and turkeys at 965 farms were culled, causing great impact on the economy and animal health. With the concerted efforts of the central and local governments, related industries and academia for HPAI control, the epidemic has been controlled, and no cases infections in humans.

Keywords: Transboundary Animal Disease (TAD), Foot and Mouth Disease (FMD), Highly Pathogenic Avian Influenza (HPAI)

INTRODUCTION

In Taiwan, there are 11,952 cloven-hoofed animal farms and 9,012 poultry farms which included 2,089 cattle farms, 2,047 goat farms, 7,846 pig farms, 5,722 chicken farms, 2,693 duck farms, 515 goose farms, and 82 turkey farms. In 1997, there are severe FMD outbreaks with clinical lesions only found in pigs. Those outbreaks were caused by Cathay topotype of O serotype of FMDV which only infected pigs and was the predominant FMDV strain found in the field till now (Table 1). Avian influenza is evolving and giving rise to a complex situation with multiple HPAI subtypes in four continents - Asia, Europe, North America, and Africa. The spread of H5 HPAI lineage 2.3.4.4 is unprecedented. Since January 2014, outbreaks have been reported in many countries, including South Korea, Japan, China, Germany, the Netherlands, the United Kingdom, Canada, the United States, and France. Unfortunately, there were also outbreaks in Taiwan starting from January in 2015 (Fig. 1).

Table 1. Cases of foot and mouth disease in Taiwan from 2009 to 2015.

Year Cases CasesNSPa Viralb Total

2009 5 3 82010 3 1 42011 7 4 112012 10 5 152013 3 0 32014 0 0 02015 1 1 2Total 29 14 43

aNSP case referred to positive result of Non Structural Protein antibody.bViral case referred to positive result of RT-PCR or virus isolation.

Fig. 1. Number of AI outbreak on surveillance between January 1 to December 31, 2015; cumulative total = 1,054 confirmed AI outbreaks

FOOT AND MOUTH DISEASE

To control and eliminate the FMD, several measures were implemented in Taiwan as follows:

Blanket vaccination Each cloven-hoofed animal should be vaccinated with FMD vaccine in Chinese Taipei. In order to strengthen the FMD prevention and control measures, the Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ), Council of Agriculture (COA) had amended Regulation in 2012. If serum neutralization (SN) antibody geometric mean titers of FMD from pig samples were less than 16 X (ruminant animals less than 32 X), those animals should be re-boosted one dose of FMD vaccine under the supervision of Local Disease Control Center (LDCC). When SN antibody

titers of tested sera from a farm were below 4X, the owner or keeper of animals should be fined NTD 30,000-150,000 (USD 1,000-5,000). The LDCCs inspect FMD vaccination situation　 of cloven-hoofed animal farms simultaneously to enhance the FMD immunization coverage.

Enhance cleaning and disinfection program in animal conveyances, auction market, and farms

For elimination of FMD virus which circulated in environment, COA had adopted the Regulations on Cleaning and Disinfection of Animal Transportation vehicles and Cages in 2015. The Branches of BAPHIQ and the LDCCs have also strengthened the cleaning and disinfection procedures in animal conveyances in auction markets and slaughter houses. LDCCs and industry organizations still guide cloven-hoofed animal farms implementing on-farm biosecurity measures to reduce the risk of spreading of the disease.

Surveillance

Farms

Six hundred pig farms and 300 ruminant farms per year were stratified and randomly sampled with a 95% level of confidence and 1% prevalence rate. Eight hundred pig farms and 160 ruminant farms per year were collected for target surveillance (e.g. low SN antibody titer farms). Those samples were collected for SN and non structural protein (NSP) antibody tests. Clinical inspection of animals would be conducted simultaneously when collecting serum samples. Auction markets

At least 1-2 pigs per source farm are randomly selected for NSP antibody testing on a daily basis. Positive samples should be traced back to the source farms for further sampling and testing.

HIGHLY PATHOGENIC AVIAN INFLUENZA

Epidemic risk assessment

Epidemic risk assessment on the 2015 HPAI outbreaks in Taiwan showed that the epidemic virus strains, novel H5N2, H5N3, and H5N8 subtypes of Eurasian H5 clade 2.3.4.4 are originated from the Korean strain and firstly introduced into Taiwan by migratory birds, and then transmitted among poultry farms by movement of people, vehicles, utensils, wild birds. HPAI outbreaks were mostly reported in central and southern Taiwan because the poultry industry are more concentrated in these areas than in northern Taiwan and most of domestic goose and duck farms in Taiwan use the open types of raising. Further analysis of the risks of transmission between poultry farms indicated that the major risks were posed by a) open type of raising, b) transport vehicles entering and exiting the premises, c) farm employees entering and exiting the premises without performing disinfection procedure, d) feed trucks and rendering trucks entering and exiting the premises, and e) possible contact of poultry with wild birds from nearby farmlands or wetlands.

Emergency response

The outbreak of this epidemic is the first time that Taiwan has experienced an HPAI with high mortality rate to water fowls. Also, outbreaks have been reported in several counties and cities. Immediately afterwards, in the evening of January 9 of this year, the Council of Agriculture has established an Animal Epidemic Disease Disaster Emergency Response Task Force, which activated an emergency epidemic prevention mechanism that included central government and local government authorities and held video conferences, studied the epidemic, and developed epidemic prevention measures. Given the abnormally high mortality rate, the detection of new types of HPAI cases and the increasing number of cases, the "Executive Yuan Avian Influenza Response Center" was established on January 14. High-level meetings were held as needed, depending on the severity of the

outbreaks. Central and local government resources were coordinated and integrated to implement disease control measures. The preemptive detailed plans and standard operating procedures were formulated as soon as possible in order to cope with the HPAI situation.

Control and prevention measures

Controlling an epidemic is like fighting a war; the government has invested much in terms of financial, administrative and human resources to effectively control and eliminate HPAI. To prevent the further spread of HPAI, the following strong measures were implemented:1. Detection, diagnosis and culling were accelerated on infected farms;2. Active surveillance of all poultry farms within a 1-kilometer radius of all infected farms was

introduced;3. Commercial slaughtering was suspended between January 12 and 14 and between January 24

and 28 to stop the movement of poultry and related vehicles;4. Ten quarantine stations were set up from January 28 to April 25 in the 5 hot spots of AI

outbreaks, i.e., Changhua, Yunlin, Chiayi, Tainan and Pingtung. Vehicles carrying eggs, feed, poultry and carcasses from the hot spots had to be disinfected at quarantine stations and obtain disinfection proof. Also, poultry health certificates were checked;

5. Only poultry with health certificates were allowed into slaughter houses;6. Eggs had to be fumigated with chlorine dioxide before leaving farms;7. Defensive quarantine and biosecurity measures were implemented on farms;8. "H5, H7 subtypes avian influenza control measures" were formulated; and9. “Regulations on Cleaning and Disinfection of Animal Transportation Vehicles and Cages” were

implemented.

ACHIEVEMENT

The current FMD vaccination rate of cloven-hoofed animal farms has been above 90%. Above 80% of cloven-hoofed animal farms had herd level protection based on the results of serological surveillance in 2015. There is no FMD case detected or found in Taiwan, Penghu, and Matsu Island since June 2013. Only 2 yellow cattle cases of A serotype of FMD were detected by our active surveillance in Kinmen Island in May and June 2015, and were quickly eradicated by stamping out, intensified surveillance program and control measures. After the implementation, prevention and control measures of avian influenza, and strict surveillance program, the avian influenza cases have decreased from 1,054 cases in 2015 to 43 cases in 2016.

CONCLUSION

Cross-border spread of animal diseases, such as the FMD and the HPAI, is still a threat to the livestock industry. Effective biosecurity facilities coupled with good practices in animal health, hygiene and animal welfare should be incorporated into the livestock industry to minimize the threat of FMD and avian influenza in Taiwan. In addition, an early warning response network with good veterinary governance and strong scientific support is a must. Stakeholders of the livestock industry also play an important role in disease control and elimination. To reduce the risk of virus circulation, we introduced concepts of production medicine to improve on-farm biosecurity measures.