Online Supplementary

Online Supplementary

Productivity Loss Estimates

Of the years lost to disease, 49.28% were taken as belonging to economically active people as noted in the household expenditure and consumption survey (Lao Department of Statistics 2009). The estimate of 3.2 hours from each day contributing directly to the economy was used based on the 2009 Socio Economic Indicators (Lao Department of Statistics 2009). Years of productivity lost per lifetime was calculated and estimates of total lifetime losses per person were based on income levels found in the 2005 Housing Census (Lao Department of Statistics 2006). The HCM method assumes 100% income loss for the entire duration of time a person is ill as determined by the loss of DALYs per year to the diseases of interest.

No value was assumed for unpaid family work, therefore this model does not account for the losses incurred by homemakers. Fulltime students were also not included in the productivity loss estimates. The productivity losses incurred by economically active children were however included. Estimations of lost productivity were made for individuals between 14-55 years of age. Productivity estimates in the form of hourly revenue were used from Socio Economic Indicators Survey 2007/2008 (Lao Department of Statistics 2009). This survey reported productivity in regions of Laos. These figures were converted to annual productivity and divided by the population of each sector to generate annual per capita income estimates. Travel costs were incorporated into the model for hospital cases but were found to be negligible. The figures applied in the model are shown below in Table 1.

Table 1: Per Capita Income by Region

Monthly Agriculture Revenue (million kip) / Monthly Household Business (million kip) / Total Annual Productivity (million kip) / Estimated Total Annual Revenue ($US) / Per Capita Income
($US)
Huaphanh / 40,312 / 18,490 / 705,624 / 87,060,333 / $309.89
Oudomxay / 48,205 / 36,180 / 1,012,620 / 124,937,693 / $471.14
Luang Prabang / 67,282 / 152,855 / 2,641,644 / 325,927,699 / $800.73
Xieng Khouang / 40,185 / 39,255 / 953,280 / 117,616,286 / $512.27

Although other countries have reported the use of tongue inspections of live animals to prevent the sale of heavily infected pigs, there is insufficient evidence to suggest this practice occurs in Lao PDR (Praet et al. 2010). Personal communications further indicated that the high demand for pork in the country guarantees the sale of pigs, even if they appear to bear some cysts (Conlan 2010).

Variables List

This model utilised a Markov decision tree in order to simulate the progress of disease through society. Furthermore, parametric bootstrapping (a form of Monte Carlo Sampling) was utilised to account for uncertainty within the variables. The complete list of variables used, their values, sources and the statistical distribution applied are shown in the table below.

List of variables and assumptions used in model

Variable Name / Region / Average Value / Statistical Distribution Used / Source
Exchange Rate / 8100KIP : USD$1 / - / Assumed
Human Health / Cysticercosis Rate / Huaphan / 0.02 / Beta / (Conlan et al. Submitted)
Oudomxay / 0.03 / Beta / (Conlan et al. Submitted)
Luang Prabang / 0.02 / Beta / (Conlan et al. Submitted)
Xieng Khuang / 0.02 / Beta / (Conlan et al. Submitted)
Trichinellosis Rate / Huaphan / 0.18 / Beta / (Conlan et al. Submitted)
Oudomxay / 0.19 / Beta / (Conlan et al. Submitted)
Luang Prabang / 0.19 / Beta / (Conlan et al. Submitted)
Xieng Khuang / 0.18 / Beta / (Conlan et al. Submitted)
Taeniasis rate / Huaphan / 0.02 / Beta / (Conlan et al. Submitted)
Oudomxay / 0.04 / Beta / (Conlan et al. Submitted)
Luang Prabang / 0.04 / Beta / (Conlan et al. Submitted)
Xieng Khuang / 0.02 / Beta / (Conlan et al. Submitted)
Health Seeking for Trichinellosis/Taeniasis / Luang Prabang / 0.23 / Beta / (Conlan et al. Submitted)
Oudomxay / 0.20 / Beta / (Conlan et al. Submitted)
Huaphan / 0.17 / Beta / (Conlan et al. Submitted)
Xieng Khuang / 0.18 / Beta / (Conlan et al. Submitted)
Rate of hospitalization due to NCC / All / 0.02% / Beta / (Ong et al. 2002)
DALY for Cysticercosis / All / 9/1000 / - / (Praet et al. 2009)
Background Death Rates / All / (See table) / - / (WHO 2004)
Animal Health / Average no. Of pigs per person / All / 4.50 / - / (Conlan et al. Submitted)
Average Pig (live) Weight / All / 56.70 / Normal / (Conlan et al. Submitted)
Carcass Weight / All / 70% of live weight / - / (Womach 2005)
Average Offal Weight / All / 10% of Carcass weight / - / Assumed
% Carcass's with light cysts / All / 4.50% / Beta / (Conlan et al. Submitted)
% of Carcass's with heavy cysts / All / 5.80% / Beta / (Conlan et al. Submitted)
Cysts attributable to Taenia Solium / All / 2.72% / Beta / (Conlan et al. Submitted)
Human Medical Costs / Albendazole / All / $US0.596/tablet / Gamma / (Conlan et al. Submitted)
niclosamide / All / $US0.864/tablet / Gamma / (Conlan et al. Submitted)
Human Hospital Costs / Treatment / All / 1.85 / Normal / (Khamlome 2010)
Room Charge / All / 1.85 / Normal / (Khamlome 2010)
Travel / All / 3.70 / Normal / (Khamlome 2010)
Hospital Stay (Daily) / All / 5.56 / Normal / (Khamlome 2010)
CT Scanner services / All / 111.11 / Normal / (Khamlome 2010)
Average length of Stay / All / 3 Days / - / (Khamlome 2010)2010
Pork Prices / Meat / All / 3.70 / Normal / (Conlan et al. Submitted)
Fat and meat / All / 3.09 / Normal / (Conlan et al. Submitted)
Offal / All / 2.47 / Normal / (Conlan et al. Submitted)
Fat / All / 1.60 / Normal / (Conlan et al. Submitted)
Welfare Losses / Annual
Income Per Capita / Huaphan / 310.08 / - / Derived from population and regional income level from (Lao Department of Statistics 2006)
Oudomxay / 471.44 / - / Derived from population and regional income level from (Lao Department of Statistics 2006)
Luang Prabang / 801.22 / - / Derived from population and regional income level from (Lao Department of Statistics 2006)
Xieng Khuang / 512.59 / - / Derived from population and regional income level from (Lao Department of Statistics 2006)
Proportion of economically active individuals per region / - / - / - / Derived from population and regional income level from (Lao Department of Statistics 2006)

Background mortality was based on the following table. Data was derived from (WHO 2004) and the Results of the population and housing census (Lao Department of Statistics 2006).

Median / Proportion of annual mortality
0 / 15.7%
2 / 12.3%
7 / 4.5%
12 / 2.9%
17 / 3.2%
22 / 2.7%
27 / 2.5%
32 / 2.6%
37 / 3.0%
42 / 3.3%
47 / 4.1%
52 / 4.3%
57 / 4.3%
62 / 5.1%
67 / 4.7%
72 / 5.3%
+75 / 19.5%

Sensitivity Tests

Hospitalisation rate due to NCC was held constant at 2% for the extent of the sensitivity tests.

Proportion of Carcass lost to disease

This section contains sensitivity tests performed on the static figure assigned to the value for the proportion of the carcass that was lost due to cysts. Due to data limitations, real observations are not available on the amount of a pig carcass that is lost due to abattoir workers cutting away lightly infected meat and as such, a static value was used. For the sensitivity testing, estimates were generated under the scenario that 80% of the carcass would be wasted followed by a 20% scenario. The results indicate that the carcass wastage variable plays a significant part in determining animal sector losses and therefore total direct costs. However, when the human capital method (HCM) is used to generate human sector losses, the overall impact of the losses in the animal sector are somewhat negligible as the HCM becomes the primary driver of costs.

Per Person Costs with 80% Carcass Loss

Mean / LCI 95% / HCI 95%
Huaphanh / $1.39 / $1.05 / $1.83
Luang Prabang / $3.02 / $2.41 / $3.68
Oudomxay / $1.93 / $1.51 / $2.46
Xieng Khuang / $2.05 / $1.61 / $2.60

80% Carcass Wastage

Huaphan / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $90,238 / $24,231 / $206,200
Human Sector / $11,036 / $564 / $46,345
Total / $101,274 / $30,364 / $219,688
HCM / Human Sector / $298,892 / $239,803 / $363,514
Total / $389,131 / $295,066 / $515,517
Luang Prabang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $133,627 / $34,836 / $311,298
Human Sector / $20,200 / $2,999 / $73,164
Total / $153,827 / $48,851 / $335,432
HCM / Human Sector / $1,093,822 / $878,623 / $1,308,363
Total / $1,227,449 / $980,025 / $1,497,029
Oudomxay / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $86,277 / $22,988 / $200,942
Human Sector / $14,627 / $1,458 / $54,233
Total / $100,904 / $32,349 / $221,945
HCM / Human Sector / $426,393 / $339,921 / $512,767
Total / $512,670 / $400,349 / $652,042
Xieng Khouang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $73,868 / $19,714 / $173,175
Human Sector / $8,977 / $582 / $36,756
Total / $82,845 / $25,544 / $185,625
HCM / Human Sector / $396,772 / $317,973 / $476,024
Total / $470,640 / $370,576 / $596,318

Per Person Costs with 20% Carcass Loss

Mean / LCI 95% / HCI 95%
Huaphanh / $1.30 / $1.00 / $1.69
Luang Prabang / $2.93 / $2.36 / $3.54
Oudomxay / $1.85 / $1.46 / $2.30
Xieng Khuang / $1.97 / $1.57 / $2.43

20% Carcass Wastage

Huaphan / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $67,639 / $18,026 / $156,704
Human Sector / $10,917 / $580 / $45,970
Total / $78,556 / $23,848 / $171,600
HCM / Human Sector / $297,282 / $237,569 / $361,063
Total / $364,921 / $282,205 / $474,310
Luang Prabang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $96,906 / $26,316 / $226,068
Human Sector / $20,570 / $3,045 / $72,956
Total / $117,476 / $39,601 / $252,502
HCM / Human Sector / $1,095,975 / $881,160 / $1,311,757
Total / $1,192,881 / $959,679 / $1,439,929
Oudomxay / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $63,116 / $16,716 / $144,372
Human Sector / $14,849 / $1,566 / $55,565
Total / $77,965 / $25,637 / $167,611
HCM / Human Sector / $426,903 / $343,591 / $514,451
Total / $490,019 / $387,014 / $609,340
Xieng Khouang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $54,751 / $14,846 / $127,003
Human Sector / $9,011 / $595 / $37,404
Total / $63,762 / $19,940 / $141,235
HCM / Human Sector / $396,851 / $320,354 / $478,465
Total / $451,602 / $359,784 / $556,903

Discount Rates

This section contains sensitivity tests performed on the discount rate used in the model. This variable was held static at 5% for the results of the model run in the main article. However, Lao being a developing nation, a significantly higher discount rate should be considered. As such, the model was run additional times with 8% and 12% discount rates. The results indicate that even with the high discount rate of 12%, losses due to the pig-associated zoonotic diseases of interest have a significant impact on the economy of the 4 selected regions of Lao PDR.

Per Person Costs with 8% discount rate

Mean / LCI 95% / HCI 95%
Huaphanh / $1.25 / $0.98 / $1.57
Luang Prabang / $2.88 / $2.31 / $3.45
Oudomxay / $1.80 / $1.44 / $2.21
Xieng Khuang / $1.92 / $1.55 / $2.33

Total Costs by Region with 8% discount rate

Huaphan / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $54,488 / $14,213 / $128,061
Human Sector / $8,891 / $475 / $37,223
Total / $63,379 / $19,509 / $140,525
HCM / Human Sector / $295,698 / $236,788 / $357,555
Total / $350,186 / $275,951 / $441,819
Luang Prabang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $78,984 / $20,740 / $183,471
Human Sector / $16,395 / $2,417 / $58,204
Total / $95,379 / $31,490 / $205,036
HCM / Human Sector / $1,093,550 / $874,076 / $1,306,237
Total / $1,172,534 / $940,600 / $1,403,632
Oudomxay / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $51,702 / $13,884 / $121,785
Human Sector / $12,312 / $1,274 / $47,334
Total / $64,014 / $20,782 / $139,130
HCM / Human Sector / $425,096 / $342,096 / $511,364
Total / $476,797 / $381,114 / $585,537
Xieng Khouang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $44,678 / $11,726 / $102,973
Human Sector / $7,493 / $480 / $31,051
Total / $52,171 / $16,046 / $113,612
HCM / Human Sector / $395,945 / $319,470 / $473,725
Total / $440,623 / $355,171 / $534,230

Per Person Costs with 12% discount rate

Mean / LCI 95% / HCI 95%
Huaphanh / $1.21 / $0.95 / $1.49
Luang Prabang / $2.84 / $2.30 / $3.39
Oudomxay / $1.75 / $1.41 / $2.12
Xieng Khuang / $1.87 / $1.51 / $2.26

Total Costs by Region with 12% discount rate

Huaphan / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $44,235 / $12,012 / $102,478
Human Sector / $7,166 / $374 / $29,839
Total / $51,401 / $16,410 / $112,526
HCM / Human Sector / $294,499 / $236,596 / $353,527
Total / $338,734 / $267,915 / $418,421
Luang Prabang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $63,946 / $17,148 / $147,146
Human Sector / $13,584 / $1,981 / $47,093
Total / $77,531 / $25,844 / $163,736
HCM / Human Sector / $1,090,331 / $879,301 / $1,302,676
Total / $1,154,277 / $935,369 / $1,379,272
Oudomxay / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $42,262 / $11,555 / $98,552
Human Sector / $9,822 / $1,018 / $36,885
Total / $52,084 / $16,944 / $111,774
HCM / Human Sector / $422,528 / $339,958 / $505,967
Total / $464,791 / $372,888 / $561,387
Xieng Khouang / Productivity Loss Method / Costs / Mean / LCI 95% / HCI 95%
None / Animal Sector / $36,106 / $9,642 / $83,651
Human Sector / $5,920 / $359 / $24,754
Total / $42,027 / $13,075 / $90,944
HCM / Human Sector / $393,086 / $316,393 / $471,722
Total / $429,193 / $345,914 / $519,490

Univariate Analysis

This section displays and discusses results of univariate analysis conducted with rate of hospitalisation due to NCC held constant at 2%.

Total Costs without Human Capital Method

If the results were modelled without the inclusion of human productivity losses, the two most influential variables to the results are the proportion of cysts on carcasses attributable to T. solium and the average weight of pigs. The proportion of NCC cases leading to hospitalisation was found to be third most influential. Results were consistent across all four provinces.

Total Costs with Human Capital Method

The results indicate that the annual income of the ill had the greatest influence on the results followed by proportion of cysts in pigs attributable to T. solium and the average weight of pigs. The proportion of NCC cases that lead to hospitalisation was seen to be the fourth most influential variable in the base case model.

References

Conlan J (2010). Enquiry on Pork Prices. Personal communication

Conlan J, Vongxay K, Khamlome B, Dorny P, Sripa B, Elliot A, et al. (Submitted). A cross-sectional study of Taenia solium in a region where four Taenia species are co-endemic reveals competition may be protective. American Journal of Tropical Medicine and HygieneIn review.

Khamlome B (2010). Hospital Data. Personal communication

Lao Department of Statistics (2006). Results from the Population and Housing Census 2005. Department of Statistics of Lao PDR, Vientiane Capital.

Lao Department of Statistics (2009). Survey results on expenditure and consumption of household 2007/2008. Ministry of Planning and Investment, Vientiane City.

Ong S, Talan DA, Moran GJ, Mower W, Newdow M, Tsang VC, et al. (2002). Neurocysticercosis in radiographically imaged seizure patients in U.S. emergency departments. Emerg Infect Dis8:608-613.

Praet N, Geerts S, Nforninwe DN, Berkvens D, Quet F, Preux PM, et al. (2009). The Disease Burden of Taenia solium Cysticercosis in Cameroon. PLOS NEGLECTED TROPICAL DISEASES3:e406-e406.

Praet N, Kanobana K, Kabwe C, Maketa V, Lukanu P, Lutumba P, et al. (2010). Taenia solium cysticercosis in the Democratic Republic of Congo: how does pork trade affect the transmission of the parasite? PLoS Negl Trop Dis4.

WHO (2004). Estimated healthy life expectancy (HALE) at birth and age 60, by sex, WHO Member States, 2002. World Health Organisation, Geneva.

Womach J (2005). Agriculture: A Glossary of Terms, Programs, and Laws, 2005 Edition. The Library of Congress, Washington.

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