diseases of swine

1. 3 Oct 2018,
The Current Status of Major Emerging and
Re-emerging Swine Diseases in China

2. Total Animals in Farm and Slaughtered in 2016, China
2
China Animal Disease Control Center (CADC)
Unit: ten thousand
Animal
Species
Cattle Horse Donkey Camel Pig Goat Poultry Rabbit
Animal
in farm
10667.9 550.7 456.9 38.1 43503.7 30112.0 589919.7 20277.4
Animal
slaughtered
5110.0 160.5 216.9 9.8 68502.0 30694.6 1237300.0 53688.6

3. Emerging and Reemerging Swine Diseases in the World
PRRS PCV2
ASF
PED
SVA
Infection
PCV-3
PDCoV SeACoV
TTSuV
Infection
PBoV
PToV
Infection
PLHV
Infection
3
China Animal Disease Control Center (CADC)
And more ……

4. Senecavirus A (SVA) Infection
CONTENTS
Porcine Circovirus Type 3 (PCV3)
Porcine Deltacoronavirus (PDCoV) Infection
Swine Enteric Alphacoronavirus (SeACoV) Infection
Porcine Epidemic Diarrhea (PED)

5. 5
Porcine Epidemic Diarrhea (PED)
#1

6. China Animal Disease Control Center (CADC) 6
➢ High prevalence in large-scale pig farms
Porcine diarrhea is very popular in pig industry, accounting for 35%-45%
of total incidence. In China, it caused more than 30 billions CHY
. The major
pathogenic agent is pEDV
Basic Situation of PED in China
863
566 527
368 323
720 720 622 604 552
646
187 6%
29
21
34
13%
90
20 26 12 14
71%
33%
3% 11%
3%
4%
2%
3%
0
20
40
60
80
0
500
1000
1500
2000
Positive
rate（%
）
Sample
No.
Sample No. Positive No. Positive rate
Active Surveillance of Gastroenteritis Diseases, 2017, China

7. PEDV Epidemiology in China in 2017
Distribution of samples
Surveillance of diarrhea in piglets in 2017 indicated that PED was
the most severe disease threatening Chinese pig industry. It was
widely prevalent and difficult in prevention and control.
Incidence rate of PEDV
7
China Animal Disease Control Center (CADC)

8. S-INDEL strain (recombinant strain): virulence varied
• In Europe: G2 group, mainly INDEL strain.
• In America: G2, G1, INDEL strain，mainly G2 group.
• In Asia: G2, G1, INDEL strain，mainly G2 group.
PEDV can be genetically separated into 3 groups: geno-type 1,
geno-type 2 and S-INDEL. All the three groups of PEDV
strains are distribution in China.
PEDV Genetic Classification
Classic (G1 group): moderate virulence
8
China Animal Disease Control Center (CADC)
New variant (G2 group, dominant >90%): high virulence
PEDV

9. Perspectives of PED Control
9
China Animal Disease Control Center (CADC)
• PEDV evolution: mutation occurred faster, variant
strains have frequently been reported.
• Integrated control measures: vaccination is not the first
line of defense, and pigs cannot be completed
protected solely by vaccination.
• Oral vaccine: vaccine is probably an ideal next-
generation vaccine for PED.

10. Senecavirus A (SVA) Infection
# 2

11. History
• 2002: first isolation, USA
➢ The only representative strain of Senecavirus A species in the new
genus Senecavirus.
➢ Exotic disease and limited geographic distribution.
• 2007: suspected to be SVA-associated disease, Canada
➢ 80% of 187 pigs exhibited vesicular lesions and suspected to be SVA-
associated vesicular disease.
• 2010 & 2012: first evidence of vesicular disease
➢ Occurred in Indiana of the US, the first evidence of association of SVA
with porcine vesicular disease
• 2015: first outbreaks, Brazil, China, Thailand
➢ Increasing number of SVA outbreaks in Brazil and US.

12. 12
Senecavirus Global Distribution, 1988 - early 2017
Although only a few countries infected with SVA, the geographic
distribution is wide, including African, American, and Asia
China Animal Disease Control Center (CADC)

13. Since 2015, SVA was detected in some provinces of
China, including Guangdong, Fujian, Henan, Hubei, etc.
However, SVA infections in Chinese pig herds remains to
be investigated.
Senecavirus A Infection in China
China Animal Disease Control Center (CADC)

14. Chinese strains late 2016 are distantly related to early
➢Chinese strains isolated
since late 2016 are distantly
related to the strains isolated
before early 2016
➢Recent outbreaks in China
only exhibited SIVD symptom
in sows and finishing pigs, but
not in piglets, which is different
with early 2016
➢Two different subclades of
Chinese strains slowly
circulating in China

15. Summary of Senecavirus Infection
Although SVA outbreaks have only been reported in five
provinces in mainland China, there is a risk that the
epidemic could spread to other SVA-free area .
Therefore, preventive measures should be implemented
as soon as possible, including, continuous
surveillance and strengthen the biosecurity. Of course,
development of vaccines is very important!

16. Porcine Circovirus Type 3 (PCV3)
# 4

17. PCV 3 History
China Animal Disease Control Center (CADC)
2015, reported in the USA
North Carolina of USA, commercial pig farm, Porcine Dermatitis
and Nephropathy Syndrome (PNDS), 10.2% increased mortality
2016, first identified in the USA
Might be involved in aborted fetus and diseased sows. .
After 2016, reported in other countries
Reported in other countries, including China, South Korea, Poland,
Italy, etc.
Collins et al. (2017) conducted a retrospective study of PCV3 in
the UK and showed that PCV3 appeared there at least 10 years
earlier than in other countries

18. PCV3 Surveillance
0.00%
10.00%
35.90%
40.00%
30.00%
20.00%
4.96%
China Animal Disease Control Center (CADC)
60.00%
50.00%
Individual Farm Slaughtering
house
Breeding boar
54.00%
0.00%
Positive
rate
Surveillance of breeding pig farms in 2017 showed PCV3 was positive in 37/88
farms in 19/25 provinces, suggesting PCV3 was distributed widely in China.
Zhang S et al. unpublished

19. 19
Porcine Deltacoronavirus (PDCoV) Infection
# 5

20. PDCoV
PDCov belongs to the genus deltacoronavirus in the family
of Coronaviridae. It is enveloped, single stranded
RNA virus.
Unlike to other enteric coronaviruses (e.g. PEDV,TGEV), the tissue
tropism of PDCoV is very wide, as it exists in a variety of organs, e.g.
intestine, blood, liver, spleen, lung, kidney, heart, tonsil, etc. CPE could be
observed after first infection of PK15 cells.
20
China Animal Disease Control Center (CADC)

21. 21
PDCoV Infection
PDCoV is a novel virus identified in recent years, causing
diarrhea in newborn piglets and resulting in high morbidity and
mortality. PDCoV is a significant causative agent responsible for the
death of newborn piglets.
2012: firstly reported in Hong Kong
by Woo PC et al.
2014: identified in US, widely
prevalent.
Subsequently, PDCoV was isolated in
Canada, North Korea, Thailand and
Laos. Positive rate up to 25%.
2014: isolated in China, positive rate
was 25.76%-58.33%, distributed in
Henan, Jiangsu, and Guangdong, etc.
China Animal Disease Control Center (CADC)

22. 海口
22
济南
兰州 西安
郑州
南京
合肥
上海
台北
福州
南昌
长沙
杭州
广州
南宁
贵阳
昆明
武汉
成都 重庆
银川
呼和浩特
西宁
拉萨
哈尔滨
长春
乌鲁木齐
沈阳
太原
石家庄
北京
天津
澳门香港
PDCoV in China
China Animal Disease Control Center (CADC)
Since 2014, PDCoV was isolated from many provinces, including
Jiangsu, Anhui, Hubei, Heilongjiang, Jiangxi, Sichuan and Shanxi
provinces, etc.

23. 23
PDCoVs Control
• No vaccine available. Biosecurity, e.g. disinfection
are important in prevention and control of the
disease.
➢ Differential diagnostics: with TGEV, PEDV
➢ Vaccine development: urgently needed.
➢ Retrospective tracing: need to be conducted
China Animal Disease Control Center (CADC)

24. 24
Swine Enteric Alphacoronavirus (SeACoV) Infection
# 6

25. 25
• Outbreaks of diarrhea in newborn piglets in
southern China since February 2017.
• SeACoV was identified by Yao-Wei
Microbiol, 2017) --- Representative
China Animal Disease Control Center (CADC)
Huang
of the
(Vet
fifth
porcine coronavirus.
• Related to the bat coronavirus HKU2 discovered in the
same region a decade ago. 75-aa substitution and
2-aa insertion compared to HKU2: crossed
species barrier.
• SeACoV is likely antigenetically distinct from PEDV
,
TGEV and PDCoV
.
Discovery of SeACoV

26. SeACoV
Analysis of S gene indicated:
The SeACov did not belong
to alphacoronavirus but
was genetically related to
betacoronavirus.
A hybrid S protein
However, phylogenetic analysis indicated that these HKU2-
related CoV strains did not belong to alphacoronavirus but
was genetically related to betacoronavirus.
China Animal Disease Control Center (CADC) 26

27. SUMMARY
• Long-distance transmission ；
• huge threats to Chinese pig industry.
• Info sharing: novel agents and emerging agents
• Technology sharing : CADC, particularly for new
agents.
• Cooperation: OIE, FAO, WHO…
27
China Animal Disease Control Center (CADC)

28. Thank you for your attention!
28

29. 29
Question?
Jianqiang Ni: cadcnjq@163.com
Yuliang Liu: ylliu0905@163.com
Zhi Zhou: zhouzhi1@126.com
Chuanbin Wang: nvdcwang@sina.com