A participatory Ecohealth study of smallholder pig
system in upland and lowland of Lao PDR
P. Inthavong, K. Blaszak, P. Durr, B. Khamlome, V. Somoulay, J. Allen, J. Gilbert, H. Holt and K. Graham

 Purpose and background of the project
 Research methodology
 Results
 Intervention options
 Discussion and recommendation

 To conduct baseline seroprevalence
surveys of key pig diseases and pig
related zoonoses
 To evaluate public health risks of pig-
raising and pork consumption in one
upland and one lowland province in Lao
PDR

- Smallholder pigs owned by 50-
70% of village households
- No prior epidemiological
prevalence surveys and risk
analysis
- Regional increase in zoonoses
and increasing disease
outbreaks
- Health and production risks

A cross-sectional data collection including
blood sampling from HUMAN and PIGS with
questionnaire survey for risk factors
 3 sets of questionnaires
 Village head to get general village information
 Human
 Pig owners

 Introduction of the principle of Ecohealth with
participatory sessions in teams that included
 Introduction of the project, diseases and
known zoonoses risks
 Conducting practice random sampling,
questionnaire interviews
 How to collect pig and human blood samples
under ethical conditions

Study designs
 2 provinces were selected
 1 represent upland
 1 represent lowland
 30 villages from each province
 15 persons and 15 pigs per village

Study designs
Multistage random sampling
 random selection of village: PPP:Villages
are randomly sampled weighted by human
population
 random selection of HH
 random selection of individuals

 Structuring sampling frames for humans and pigs
◦ Sampling based primarily on human population (not pig
population)
 Ethical issues
 informed and signed consent forms for human participants
 individual results within each village not identified by
household names
 Appropriate modest health practical gifts to participating
households
 Village level feedback of overall results

 Humans
 JEV
 Hep E
 Taenia/cysticercosis
 Trichinella
 Pigs
 JEV, Hep E, Trichinella
 CSF
 PRRS
 Erysipelas
 FMD (Types O, A and Asia 1)

 Data entry and manipulation using new web based
program: SurVet
 Data analysis on Stata program

Results
Number of pigs and people sampled
Study location People Pig
ILRI Luangprabang 447 310
(north)
ILRI Savannakhet 435 365
(south)
Total 882 675
Sample test
All tests carried out in Laos using commercial kits
Human samples were tested NCLE
Pig sample NAHC

Results: Crude seroprevalence
Disease Humans Pigs
JEV IgM 4.4% 8.5%
JEV IgG 75.2%
Hep E IgG 64% 61.4%
Trichinella 47.3% 13.7%
Taenia solium IgG 2.9%
Cysticercosis IgG 4.7%
Erysipelas 47.5%
CSF 10.3%
PRRS 8.2%
FMD (ABC non-structural ELISA) 2.1%
* Prevalence data reported above has not been adjusted for
population weighting factors

Antibody test Nth (n= 310) Crude Sth (n= 365) Crude
Seroprev Seroprev
JEV IgG 75.4% 81.8%
JEV IgM 12.2% 6.7%
HEV 81.9% 50.0%
Trich 13.5% 9.0%
CSF 7.4% 14.7%
PRRS 11.3% 9.6%
Erysipelas 63.5% 30.2%
FMD 2.0% 2.8%

Multivariate analysis of HEV in pigs
Factors OR (95% CI) p-value
Age 1.58 (1.26 to 1.99) <0.001
South 0.14 (0.08 to 0.24) <0.001
Sow catergories 1.55 (1.10 to 2.18) 0.01

Adjusted risk factors for human hepatitis E
Adjusted ORs were derived from a multivariate logistic analysis with random effects
Adj. OR (95% CI) P-value
Slaughter Pigs 1.64 (1.00, 2.70) 0.05
Southern vs. Northern Province 4.52 (2.93, 7.00) <0.001
Age of person 1.71 (1.42, 2.05) <0.001
Increased distance from pigs 0.82 (0.69, 0.98) 0.04
Female vs. male 0.67 (0.46, 0.99) 0.04

Investigation of risk factors for human cysticercosis or Taenia
Risk factors associated with higher cysticercosis or Taenia sero-positive
levels:
Odds Ratio (95% CI)
Non-use of toilets is clear risk factor 2.65 (1.37, 5.12)*

Investigation of risk factors for human JEV
Risk factors associated with higher JEV seropositive levels:
Odds Ratio (95% CI)
Age , > 20 years tended to be associated
with greater seropositive 6.50 (0.89, 47.66)
Nearly all people answered that they used mosquito nets – so no real
comparison of non-use as a risk factor
Data do not support that distance from pigs up to 150 metres is associated
with reduced risk

Combined Human Combined Pig
Prev 61.4% Prev 64.0%
North – Upland
50.00% 81.9%
South- Lowland
77.9% 50.00%

 Information Communication
and Education (ICE)
materials development
workshop
 Result feedback meetings
 Village ICE pilot testing
 Human health risk reduction
options
 Village biosecurity for pigs
 Modification and finalization
of IEC materials for pig and
human health ris reduction
need to be done

 Significant level of exposure of tested diseases
were found in this atudy
 Detailed risk related analysis have been done
just only for HE
 Detailed risk factor analysis and interpretation
and report for all diseases need to be done
 Using collected serums to test for other
diseases
 Risk reduction PA

 Time constraints
 Geographical/seasonal aspects
 Multisectorial involment
 Test validation
 Data analysis skills

Blaszak, K1., Durr, P.2, Khamlome, B.3, Somoulay, V.4,
Allen, J.2 and Gilbert, J.5 Holt, H.5
1 NAHC, Lao PDR; 2 AAHL, CSIRO Austria; 3 DHP, Lao PDR; 4 NCLE, Lao PDR; 5ILRI, Lao PDR