Occurrence of Trichinellosis in indigenous pigs of
ethnic minorities in Vietnam
Vu Thi Nga, Trang Le Thi Huyen, Hung Nguyen-Viet, Sinh Dang-Xuan, Anne
Mayer-Scholl, Diana Meemken, Nguyen Lan Anh, Maximilian Baumann,
Pham Thi Ngoc, Fred Unger

OBJECTIVES
• Determine the
seroprevalence of pig
trichinellosis in Da Bac
district, Hoa Binh
province, Vietnam in 2018
• Identify potential risk factors
against Trichinella spp. in
indigenous pigs

METHODS
Study design
-Cross-sectional study June – September 2018
-2 parts:
oQuestionnaire survey: knowledge and
perception on food-borne parasitic diseases and
related husbandry practices
 6 communes in Da Bac – 131 households
oPig blood collection
2-3 pigs per household
352 pig blood samples within 131 households
Tests: Trichinella antibod, in-house ELISA
developed by BfR, Natioanl Reference Lab for
Trichinalla
Da Bac, Hoa Binh province

Socio-demographic
Information of households
Characteristics
Male (n=91) Female (n=40) Total (n=131)
% % n %
Age group
18-30 11 20 18 13.7
31-45 49.4 40 61 46.6
46-60 35.2 20 40 30.5
>60 4.4 20 12 9.2
Ethnic Group
Tay 89 82.5 114 87
Dao 9.9 12.5 14 10.7
Viet/Kinh 1.1 5 3 2.3
Occupation
Farmer 99 97.5 129 98.5
Other 1 2.5 2 1.5
Education attainment
Primary school or less 26.4 42.5 41 31.3
Secondary school 37.4 40 50 38.2
High school and higher 36.2 17.5 40 30.5
RESULTS AND
DISCUSSION

Livestock system and
hygiene conditions
RESULTS AND
DISCUSSION
111
(85%)
20 (15%)
Pit-latrine Flushing toilet
Toilet model (n=131)
112
(85%)
19
(15%)
Yes No
Presence of rat (n=131)
Information No. of farms (%)
Raising system
Fenced 45 (34.4)
Roaming 21 (16.0)
Semi-fencing 65 (49.6)
Farm scale
<10 pigs/farm 102 (77.9)
≥10 pigs/farm 29 (22.1)
Pig origin from the same village
Yes 131 (100)
No 0 (0)
Sell pig at the same village
Yes 126 (96.2)
No 5 (3.8)
Slaughtering pig at home
Yes 129 (98.5)
No 2 (1.5)
Raising other animals at farm (dog, cat, poultry, cattle) are
common

RESULTS AND
DISCUSSION
Consumption of raw pork
Consumption of raw/fermented pork among genders
* No significant different between gender (Fisher exact test, p>0.05)
Frequency Male Female Total
Daily 0 0 0
Once a week 1 1 2
Once a month 4 1 5
Others (less often, only on
cultural events) 19 11 30
Never 67 27 94
Total 91 40 131

RESULTS AND
DISCUSSION
Knowledge
• 18/131 (13.7%) said they know at least 1 FBPD
- Only 2/18 and 5/18 and can name Trichinellosis
and Cysticercosis
- 3/7 knew that eating is the mode of
transmission, but did not know what type of
food.
- The rest (11/18) mentioned FMD, leptospirosis,
Streptococcus.

RESULTS Perception on FBPD
Figure 3. Perception of participants on FBPD

RESULTS AND
DISCUSSION
Trichinellosis sero-prevalence
in pigs
Location
Number of pigs (352)
N Trichinellosis positive n (%)
Muong Chieng 50 5 (10.0)
Giap Dat 68 10 (14.7)
Doan Ket 60 7 (11.7)
Cao Son 76 10 (13.2)
Tan Minh 60 13 (21.7)
Trung Thanh 38 3 (7.9)
Total 352 48 (13.6)
• Dien Bien & Son La 2012/Antibody ELISA: 6.8% (Nga et al.)
• Son La 2009/Antibody ELISA: 19.9% (Nga et al.)

RESULTS AND
DISCUSSION
Variable
No. of pos
pigs/n
ORadj (95%
CI)
p-Value
Sex
Female 35/205 Ref -
Male 13/147 0.5 (0.2-1) 0.04
Age groups ≤ 6 months 19/199 Ref -
7-12 months 16/105 1.8 (0.8-4.1) 0.18
>12 months 13/47 4.2 (1.6-11.0) 0.003
Weight
≤ 15kg 22/209 Ref
> 15kg 26/143 2.0 (1.0-4.0) 0.06
Farm scale
>= 10
pigs/farm
12/84 Ref -
< 10 pigs/farm 36/268 0.9 (0.4-2.3) 0.84
Pig raising system Fenced 15/123 Ref -
Free roaming 11/53 2.2 (0.7-6.6) 0.18
Semi 22/176 1.0 (0.4-2.5) 0.92
Toilet type at farm Pit-latrine 36/297 Ref -
Flushing 12/55 2.3 (0.9-6.1) 0.09
Deworming Yes 43/290 2.1 (0.7-6.6) 0.2
Keeping dog at farm Yes 41/266 2.1 (0.8-5.8) 0.13
Raising buffalo Yes 17/112 1.3 (0.6-3.0) 0.51
Raising cattle Yes 26/141 2.1 (1.0-4.7) 0.05
Raising chicken Yes 30/194 1.4 (0.7-3.1) 0.37
Raising cat Yes 24/160 1.3 (0.6-2.7) 0.55
Presence of rat at farm Yes 42/299 1.7 (0.4-7.9) 0.47
Household member consume raw pork Yes 15/102 1.1 (0.5-2.6) 0.79
Univariate GLMM results
(Random Effect - Individual Pig level: Commune ||Pig farm level: Commune, Household)
Risk factors of Trichinellosis

RESULTS AND
DISCUSSION
Risk factors of Trichinellosis
Factors
Adjusted
odds ratio
95% CI p-value
Age (younger than 6 months
as a reference)
7-12 months 2.1 (0.9 – 4.9) 0.09
>12 months 4.4 (1.7 – 11.5) <0.01
Raising cattle 2.4 (1.1 – 5.2) 0.03
Multivariable GLMM result of pig individual level
• Multivariable GLMM result
- Household level: No significant association
- Individual level: Age of pigs, practice of raising cattle

Additional analysis
• Response to the food safety “crisis”
linked to the Cysticercosis in school
students in Thuan Thanh, Bac Ninh
province February, 2019
Sero-prevalence
of Cysticercosis
Nhân Dân, 15/3/2019 https://www.nhandan.com.vn/y-te/item/39514702-57-tre-mam-non-bac-ninh-duong-tinh-voi-san-
lon.html
• >400 students checked at hospital by
concern of their parents, 10-25% positive
with cysticercosis (ELISA)
• Slow reaction of MOH
• Caused food safety scandal and panic
• Further work on Cysticercosis in pigs

CONCLUSIONS
• Risk perception of local people is good, but
knowledge on zoonoses rather poor
• Eating behavior: consumption of raw pork during
ceremonies/parties still happens
• High prevalence of Trichinellosis (13.6%)
• Trichinellosis in pigs increased by age

NEXT STEPS
• Intervention to improve knowledge
and husbandry practice of local
people
• Lack of meat inspection, local
butchers targeted with simple
guideline
• Understand raising practice of
positive cases
• Cross-check the pigs and human
positive results to find related risk
factors: One Health

Acknowledgements

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