**5. Detection of outbreak farms**

Detection of outbreak farm signifies the start of implementing control measures by animal health service. Large number of outbreak farms in the epidemics of 2010/2011 and 2014/2015 were attributed to the late detection of the infection, and FMD virus was al‐ ready spread out at the time of confirming the index case [8, 9].

#### **5.1. Delayed detection**

ers. Then, he put new underwear and shirts provided by the local government. But, he put again the same trouser that he wore in working because he had no spare one. While he took a bath, his jean was wrapped in a vinyl bag after being sprayed disinfectant. He returned back home by his own car in which no disinfection measures were implemented. He worked at the port‐processing plant for three or four occasions, starting on 8 May. FMD virus was probably transmitted by this person considering that the index farm, on which 330 (4.0%) of 8,302 pigs showed clinical signs or died at the time of culling, was heavily contaminated at the time of culling. FMD virus must survive in environment such as interior of his car, and transmitted to the pork‐processing plant and adjacent pig hous‐ es during 17 days of interval between the completion of culling (5 May) and the most like‐

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

By carrying out epidemiological investigation, we can estimate how long has the disease been on the farm, where did the disease come from, and where the disease might have spread to. To establish a likely time period of infection dynamics took place in animals of the farm, aging clinical lesions is important. Looking for the oldest lesions allows identify‐ ing the time of first infection in the herd. Clinical examination starts by taking history about type and time of clinical signs and affected animals from the farmer. Then, the ani‐ mals from a distance to see general demeanor, salivation, lameness, or ataxia were ob‐ served. When we examine the individual animal, check the mouth (especially in cattle)

The clinical signs of FMD were the most clearly manifested in pigs followed by dairy cat‐ tle comparing to other species. In the epidemic of 2010/2011, only 2.6% of the dairy cattle farms and 1.9% of the pig farms were subclinically infected, while no clinical signs of FMD was observed in 10‐20% of the outbreak farms with beef cattle, deer, or goats. For beef cattle, the number of farms with ulcers (n = 408, 28.6%) was higher than that showing vesicles (n = 316, 22.2%). For dairy cattle, on the contrary, vesicles (n = 166, 32.6%) were more frequent than ulcers (n = 107, 21.0%) in dairy cattle farms. In 58.9% of the pig farms, vesicle was the most dominant sign of FMD. In pigs, more severe signs, such as lameness or ataxia (14.6%) and shedding of claws (4.6%), were also distinctively shown. Another clinical characteristic observed in the 2010/2011 FMD epidemic was sudden death of suck‐ ling piglets, which was observed in 21.2% of pig farms. The average age of the oldest lesion in an outbreak farm was higher in the vaccinated than the non‐vaccinated in cattle, while it was higher in non‐vaccinated in pigs. Considering that vaccination was firstly performed on cattle then on pigs, and the outbreaks continued only in pig farms at the later phase of the epidemic, difference of lesions' age between cattle and pig at detecting

In the epidemic of 2014/2015, any clinical signs of FMD were observed in all of the 185 outbreak farms. Vesicles, which were observed 65.0% of the outbreak pig farms, were the most promi‐

seemed mainly associated with farmers' attention and recognition [11].

ly date of first infection (22 April) [10].

**4. Clinical signs**

then the feet (in pigs) in order.

In case of the 2010/2011 epidemic, implementation of control measures was delayed due to inappropriate diagnosis. When the first suspected case was reported on 23 November 2010, the NSP antibody test was conducted on the clinically suspected animals which had not yet developed NSP antibody, and negative results were drawn. Three days later, when the farmer notified the abnormalities for the second time, antibody test confirmed negative results again. Antibodies can be detected by enzyme‐linked immunosorbent assay(ELISA) test from 3–5 days after appearing clinical signs of FMD. Finally, FMD was confirmed in isolating virus through reverse transcription‐polymerase chain reaction (RT‐PCR) by the QIA from the specimen taken on 28 November [12].

#### **5.2. Early detection**

On the contrary, prompt diagnosis contributed to the reduction of disease spread in the epidemic of 2002. From 9 May, 1 week after the confirmation of the first case, pen‐side antigen test, which can detect FMD virus in vesicular fluids, was used for FMD suspect cases. This test enabled confirmation of infection to be made on the farm in about 20 min. Stamping out was implemented based on clinical examination (observing vesicles in most cases) and the pen‐side antigen test results even before laboratory confirmation was made in some cases. During this epidemic, 13 of the 16 outbreak farms were culled within 24 h of diagnosis, which was an important factor in reducing the spread of the disease [6].

#### **5.3. Probability of detection**

The probability of early detection was the highest for pig farms, followed by dairy and beef cattle farms, and small ruminant farms in the case of the 2010/2011 epidemic. Almost 90% of the infected farms were detected by Day 11 of post‐infection for pig farms, by Day 13 for both dairy and beef cattle farms, and by Day 21 for small ruminant farms. As far as con‐ cerned to the detection delay, that was time passed prior to the detection of FMD infection on a farm (average ± standard deviation), was 8.1 ± 3.1 days. The detection delays were shortest for pig farms (7.1 ± 2.5 days) and longest for deer farms where a large variation was also observed (14.4 ± 8.1 days) [13].
