The authors have declared that no competing interests exist.
Conceived and designed the experiments: MFH CMB SR. Performed the experiments: MFH CMB SR. Analyzed the data: MFH CMB. Contributed reagents/materials/analysis tools: MFH CMB. Wrote the paper: MFH CMB SR.
Cystic echinococcosis (CE) is a globally distributed parasitic infection of humans and livestock. The disease is of significant medical and economic importance in many developing countries, including Iran. However, the socioeconomic impact of the disease, in most endemic countries, is not fully understood. The purpose of the present study was to determine the monetary burden of CE in Iran. Epidemiological data, including prevalence and incidence of CE in humans and animals, were obtained from regional hospitals, the scientific literature, and official government reports. Economic data relating to human and animal disease, including cost of treatment, productivity losses, and livestock production losses were obtained from official national and international datasets. Monte Carlo simulation methods were used to represent uncertainty in input parameters. Mean number of surgical CE cases per year for 2000–2009 was estimated at 1,295. The number of asymptomatic individuals living in the country was estimated at 635,232 (95% Credible Interval, CI 149,466–1,120,998). The overall annual cost of CE in Iran was estimated at US$232.3 million (95% CI US$103.1–397.8 million), including both direct and indirect costs. The cost associated with human CE was estimated at US$93.39 million (95% CI US$6.1–222.7 million) and the annual cost associated with CE in livestock was estimated at US$132 million (95% CI US$61.8–246.5 million). The cost per surgical human case was estimated at US$1,539. CE has a considerable economic impact on Iran, with the cost of the disease approximated at 0.03% of the country's gross domestic product. Establishment of a CE surveillance system and implementation of a control program are necessary to reduce the economic burden of CE on the country. Cost-benefit analysis of different control programs is recommended, incorporating present knowledge of the economic losses due to CE in Iran.
Cystic echinococcosis (CE), caused by the tapeworm
Cystic echinococcosis (CE), a chronic disease caused by the larval form of the tapeworm
Cystic echinococcosis is a cosmopolitan zoonosis, with highly endemic areas especially prevalent in regions of South America, North Africa, China, and the Middle East
Recently, the World Health Organization (WHO) included CE in a subgroup of selected Neglected Tropical Diseases (NTDs) to be addressed within its 2008–2015 strategic plan for control of NTDs
Although CE is assumed to be a significant public health and economic problem in Iran, the extent of its socioeconomic impact is not fully understood. Economic losses due to CE in ruminants have been previously estimated in three provinces of Iran (Khuzestan, North Khorasan, and Ardabil)
Population data for Iran for 2010 were extrapolated from the 2006 population census, with 71.8% of the population living in urban areas
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Population (2010) | 74,733,230 | Individuals | Fixed | - |
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Urban/Rural | 71.8/28.2 | Percent | Fixed | - |
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Average income per day-urban | 23.48 | US$ | Fixed | - |
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Average income per day-rural | 14.09 | US$ | Fixed | - |
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Annual surgical incidence of CE | 1.27 | Per 100,000 | Uniform | 0.80–1.73 | See Methods |
Hepatic cysts | 55.5 | Percent | Fixed | - | See Methods |
Pulmonary cysts | 30.9 | Percent | Fixed | - | |
Hepatic and pulmonary involvement | 4.1 | Percent | Fixed | - | See Methods |
Other organs | 9.5 | Percent | Fixed | - | See Methods |
Undiagnosed cases of CE | 0.85 | Percent | Uniform | 0.2–1.5 | |
Length of hospital stay | 11.4 | Days | Uniform | 7–15.8 | |
Mortality among surgical cases | 2.5 | Percent | Uniform | 1–5 | |
No of absentee days for recovery | 18 | Days | Uniform | 8–28 | |
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947 | Individuals | Uniform | 599–1295 | See Methods |
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0–9 | 4.6 | Percent | - | - | |
10–19 | 14.5 | Percent | - | - | |
20–29 | 20.4 | Percent | - | - | |
30–39 | 16.9 | Percent | - | - | |
40–49 | 13.9 | Percent | - | - | |
50–59 | 10.5 | Percent | - | - | |
60–69 | 10.1 | Percent | - | - | |
70–79 | 7.5 | Percent | - | - | |
80+ | 1.6 | Percent | - | - | |
Total | 100 | Percent | - | - | |
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0–9 | 3.6 | Percent | - | - | |
10–19 | 9.7 | Percent | - | - | |
20–29 | 19.0 | Percent | - | - | |
30–39 | 19.2 | Percent | - | - | |
40–49 | 16.8 | Percent | - | - | |
50–59 | 13.9 | Percent | - | - | |
60–69 | 10.3 | Percent | - | - | |
70–79 | 6.3 | Percent | - | - | |
80+ | 1.2 | Percent | - | - | |
Total | 100 | Percent | - | - |
Based on surgical incidence.
The livestock species primarily involved in the domestic cycle of CE in Iran are sheep, goats, cattle, buffalo, and camels. Data for livestock populations and annual numbers of slaughtered animals were obtained from official government reports (
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Population | 49,976,138 | Animals | Fixed |
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6,446,354 | Animals | Fixed |
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Prevalence of CE at abattoir | 23.5 (8–39) | Percent | Normal | |
Meat production | 390,000 | Tonne | Fixed |
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Milk production | 444,004 | Tonne | Fixed |
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Skin/hide production | 64,800 | Tonne | Fixed |
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Wool production | 52,455 | Tonne | Fixed |
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Population | 22,333,547 | Animals | Fixed |
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1,912,640 | Animals | Fixed |
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Prevalence of CE at abattoir | 8 (5–11) | Percent | Normal | |
Meat production | 106,000 | Tonne | Fixed |
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Milk production | 270,157 | Tonne | Fixed |
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Skin/hide production | 18,875 | Tonne | Fixed |
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Wool production | 2,905 | Tonne | Fixed |
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Population | 7,088,984 | Animals | Fixed |
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No of slaughtered animals/year | 1,432,270 | Animals | Fixed |
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Prevalence of CE at abattoir | 20 (13–27) | Percent | Normal | |
Meat production | 360,000 | Tonne | Fixed |
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Milk production | 5,965,728 | Tonne | Fixed |
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Hide/leather production | 47,700 | Tonne | Fixed |
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Population | 191,438 | Animals | Fixed |
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No of slaughtered animals/year | 30,926 | Animals | Fixed |
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Prevalence of CE at abattoir | 12.5 | Percent | Fixed | |
Meat production | 14,900 | Tonne | Fixed |
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Milk production | 245,000 | Tonne | Fixed |
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Hide/leather production | 2,048 | Tonne | Fixed |
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Population | 151,932 | Animals | Fixed |
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No of slaughtered animals/year | 45,127 | Animals | Fixed |
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Prevalence of CE at abattoir | 32 (15–49) | Percent | Normal | |
Meat production | 1,680 | Tonne | Fixed |
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Assuming government-reported slaughter rates for sheep and goats.
Costs associated with direct and indirect losses associated with human surgical CE were assessed. Direct costs included cost of surgery, hospital accommodation, diagnostic imaging, clinical laboratory and histopathology testing, and drug costs in both public and private hospitals. The Puncture Aspiration Injection Re-aspiration (PAIR) technique, which is widely used in other parts of the world, is rarely used in Iran. Therefore, the procedure was not costed in this study. Unit costs of services were obtained from official tariffs established by the Iranian Ministry of Health and Medical Education
Indirect costs associated with human CE included lost wages due to work absenteeism during hospitalization and recovery, due to time off to stay with a child with CE, and due to CE-related mortality. Income data for urban and rural populations were obtained from official reports of the CBI. Gender specific wage data were not available for Iran or its neighboring countries. Therefore, based on studies conducted in other regions, it was assumed that women earn approximately 0.70 times as much as men
A 100% loss of daily wages or productivity was assumed for CE surgical patients for the period of hospitalization. However, no losses were evaluated for unemployed patients since government unemployment benefits, which are received by all members of society whether they work in the public or private sector, were assumed to remain unchanged during the treatment period. Since unemployment benefit coverage is most likely not complete, the cost estimation is probably underestimated, especially in rural populations. For CE patients under the age of 18 years, a 30% wage loss for a man 30–39 years of age was applied for the period of hospitalization. This was based on the assumption that a parent would need to devote a proportion of his or her time to caring for the child
Direct and indirect costs due to CE-associated losses in livestock species were evaluated. Direct costs associated with CE in livestock are due to the condemnation of livers and lungs during carcass inspections in abattoirs. A uniform distribution was applied to liver and lungs losses based on market prices across Iran (
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Live animal | 2.86 | Uniform | 2.46–3.26 | |
Liver | 10.12 | Uniform | 8.67–11.56 |
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Lung | 10.12 | Uniform | 8.67–11.56 |
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Milk | 0.50 | Fixed | - |
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Hide/skin | 1.64 | Fixed | - |
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Wool | 0.59 | Fixed | - |
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Live animal | 2.78 | Uniform | 2.40–3.16 | |
Liver | 10.12 | Uniform | 8.67–11.56 |
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Lung | 10.12 | Uniform | 8.67–11.56 |
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Milk | 0.48 | Fixed | - |
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Hide/skin | 1.14 | Uniform | 0.63–1.64 |
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Wool | 0.59 | Fixed | - |
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Live animal | 2.54 | Uniform | 2.26–2.81 | |
Liver | 8.67 | Uniform | 7.71–9.63 |
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Lung | 0.27 | Uniform | 0.24–0.29 |
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Milk | 0.38 | Fixed | - |
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Hide/leather | 1.14 | Uniform | 0.63–1.64 |
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Live animal | 2.54 | Uniform | 2.26–2.81 | |
Liver | 8.67 | Uniform | 7.71–9.63 |
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Lung | 0.27 | Uniform | 0.24–0.29 |
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Milk | 0.51 | Fixed | - |
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Hide/leather | 1.14 | Uniform | 0.63–1.64 |
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Live animal | 1.21 | Fixed | - |
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Liver | 8.67 | Uniform | 7.71–9.63 | |
Milk | 0.38 | Fixed | - |
• Assumed to be similar to that of cattle.
Indirect losses due to decreased carcass weight, reduction in milk production, decreased wool production, decreased hide/skin value, and reproductive losses were estimated. Values of livestock parameters used to estimate economic losses associated with CE were assumed to be similar to those used in previous assessments of livestock-associated CE losses
Data were compiled in Excel spreadsheets (Microsoft Corp, Redmond, WA). The risk analysis and simulation software @RISK (Palisade corp., Ithaca, NY, ver. 4.5) for Excel was used to estimate monetary costs attributed to CE infection in humans and livestock. Output variables were defined according to parameters involved in the estimation of direct and indirect costs associated with CE in humans and livestock intermediate hosts (
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Costs of hepatic CE | 593,485 | 410,640–818,157 |
Costs of pulmonary CE | 261,800 | 189,390–340,775 |
Costs of CE in liver and lung | 75,420 | 53,198–100,919 |
Costs of CE in other organs | 101,456 | 70,080–139,730 |
Direct costs of CE | 1,097,950 | 855,548–1,381,656 |
Indirect costs of CE |
372,613 | 188,873–576,448 |
Indirect costs of CE |
97,527,670 | 9,712,122–206,574,100 |
Total costs of human CE |
1,470,564 | 1,158,458–1,817,444 |
Total costs of human CE |
98,625,620 | 10,739,470–207,912,300 |
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Direct costs of CE | 12,524,960 | 4,047,542–22,354,430 |
Indirect costs of CE | 59,036,660 | 4,047,542–22,354,430 |
Total costs of sheep CE | 71,551,620 | 16,585,770–152,227,400 |
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Direct costs of CE | 1,074,601 | 608,845–1,610,484 |
Indirect costs of CE | 6,031,210 | 1,271,019–12,306,230 |
Total costs of goat CE | 7,105,811 | 2,235,714–13,586,770 |
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Direct costs of CE | 9,992,240 | 6,412,567–13,777,960 |
Indirect costs of CE | 47,920,830 | 18,608,570–84,215,220 |
Total costs of cattle CE | 57,913,070 | 27,012,570–96,117,080 |
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Direct costs of CE | 131,108 | 114,636–148,589 |
Indirect costs of CE | 787,311 | 314,762–1,273,489 |
Total costs of buffalo CE | 918,418 | 445,066–1,403,014 |
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Direct costs of CE | 13,433 | 6,201–20,886 |
Indirect costs of CE | 586,974 | 175,347–1,140,535 |
Total costs of camel CE | 600,406 | 184,034–1,158,064 |
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Direct costs | 23,726,340 | 14,323,200–34,387,130 |
Indirect costs | 114,363,000 | 51,049,920–196,475,100 |
Total costs of animal CE | 138,089,300 | 69,524,500–226,669,800 |
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24,824,290 | 15,425,180–35,444,500 |
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114,735,600 | 51,377,930–196,922,400 |
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211,890,700 | 96,003,140–344,185,200 |
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Assuming government-reported slaughter rates for sheep and goats.
Excluding asymptomatic/non-healthcare seeking human population.
Including asymptomatic/non-healthcare seeking human population.
Human CE contributed to more than 40% of the total annual cost of CE in Iran. This was mainly due to the impact of human productivity losses in the asymptomatic/non-healthcare seeking population. This figure decreased to 1.1% of the total estimated cost when productivity losses in the asymptomatic/non-healthcare seeking population were excluded. Direct costs of human CE were estimated at 1.2% of the total cost of human disease. However, direct costs accounted for three quarters of the economic losses in surgical CE cases.
Assuming government slaughter values, the median annual cost associated with CE in livestock was estimated at US$132.0 million (95% CI US$61.8–246.5 million), of which US$23.5 million (95% CI US$12.7–36.5 million) was direct and US$108.4 million (95% CI US$45.0–216.9 million) was indirect cost. Sheep and cattle CE were responsible for 48% and 42% of the total economic losses due to livestock CE in Iran, respectively. Direct costs associated with CE in livestock accounted for 10.1% of the overall cost of the disease. Indirect costs associated with CE in livestock were primarily due to losses in fecundity and milk reduction. Indirect costs due to CE in livestock intermediate hosts comprised more than 80% of the total livestock-associated costs of CE and approximately 47% of the overall cost of CE in Iran. Costs associated with sheep and goat CE, assuming the practice of home slaughtering, are found in
Scenarios | Direct costs, US$ (95% CI) | Indirect costs, US$ (95% CI) | Direct and indirect costs, US$ (95% CI) | |
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Sheep | 12,524,960 (4,047,542–22,354,430) | 59,036,660 (9,746,846–133,468,100) | 71,551,620 (16,585,770–152,227,400) |
Goat | 1,074,601 (608,845–1,610,484) | 6,031,210 (1,271,019–12,306,230) | 7,105,811 (2,235,714–13,586,770) | |
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Sheep | 25,048,910 (8,168,014–44,242,900) | 63,456,400 (12,570,030–140,369,500) | 88,505,300 (24,126,530–177,011,800) | |
Goat | 2,149,359 (1,225,908–3,259,446) | 6,400,930 (1,580,594–12,635,600) | 8,550,289 (3,359,383–15,273,460) | |
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The impact of uncertain parameters on the total monetary burden of CE in Iran and the corresponding regression coefficient values are shown in
Estimating the economic impact of a zoonotic disease is a way of quantifying the significance of the disease in both human and livestock populations. In addition, this type of analysis helps decision-makers prioritize resources for disease control and prevention. The aim of the present study was to estimate the economic impacts of CE in Iran. Findings indicated that CE costs Iran more than US$230 million per year. This is a considerable burden as this equates to about 0.03% of the country's Gross Domestic Product (GDP). A value of 0.03% of the country's GDP is in line with the findings of other studies where this value ranged from 0.003% to 0.04% of GDP (
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Iran | 74.7 | 49.9 | 22.3 | 7.1 | 232.3 | 0.03 | Present study |
Spain | 43.0 | 22.7 | 2.9 | 6.5 | 200 | 0.01 |
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Turkey | 74.7 | 25.5 | 6.3 | 11.0 | 89 |
0.01 |
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Tunisia | 9.6 | 7.2 |
1.3 | 0.8 | 14.7 | 0.03 |
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Uruguay | 3.2 | 25.0 | 0.016 |
10.4 | 9.0 | 0.04 |
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Peru | 26.2 | 14.2 |
1.9 |
5.5 |
6.3 | 0.003 |
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Jordan | 4.4 | 1.2 | 0.5 | 0.7 |
3.9 | 0.04 |
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Cost of animal CE only.
From FAOSTAT, 2010.
Indirect human losses not accounted for.
The overall cost of CE in Iran was estimated to be higher than the CE-associated monetary losses for other countries, including Jordan (US$ 3.9 million), Uruguay (US$ 9.0 million), Tunisia (US$ 14.7 million), Turkey (US$ 89 million- livestock losses only), and Spain (US$ 200 million)
In previous studies on ruminant echinococcosis economic losses due to CE have been estimated using conventional calculation methods. Livestock CE-related losses were estimated at US$459,660 in the city of Ahwaz
Based on the results of this study, the monetary burden of CE in Iran is substantial, especially when indirect costs due to productivity losses in the asymptomatic/non-healthcare seeking population were taken into consideration. Productivity losses for asymptomatic/non-healthcare seeking individuals added about US$ 100 million to the overall cost estimate of CE in the country. This estimate was based on the two community-based ultrasound studies that have been carried out in Iran. However, this was not optimal since both of the studies were conducted in rural/nomadic populations. Nevertheless CE cases are increasingly reported from urban regions. The number of CE cases from rural and urban areas was shown not be significantly different in Iran. Several studies have shown that CE is equally prevalent in rural and urban regions, especially due to the increased recreational/camping activities of the urban population and large migrations of people from rural to the urban/peri-urban regions of the country during last three decades
The ratio of community ultrasound prevalence to the annual surgical incidence of CE was 669.3, which is higher than the ratio of 45.4 found in Florida, Uruguay
A limitation of this study was how to assess productivity losses for those individuals who were not formally employed. Based on limited available data, a 30% productivity loss was assumed for women who are not officially employed outside of the home. This value was chosen because a sick homemaker indirectly affects the entire family's productivity and increases living costs of the family. Indirect costs of CE in humans and livestock accounted for more than 80% of overall monetary losses in this study, which is in agreement with the results of other studies in endemic areas
Availability of high quality epidemiological and economic data is crucial for improving the accuracy of the estimation. Lack of age-stratified CE prevalence data for livestock was another limitation of the present study. However, abattoir-based CE prevalence data tends to be underestimated due to the fact that, in Iran, animals that are slaughtered in abattoirs tend to be young and, therefore, have a lower chance of being infected compared to older animals. Another important issue is the unexpectedly low proportion of the sheep and goat population reported to be slaughtered each year (12.8% and 8.5%, respectively). These figures reflect animals that are slaughtered in registered abattoirs, which is almost definitely an underestimation. Many people, especially those living in rural/suburban areas, practice home slaughter. In addition, a number of unregulated abattoirs also exist within the country. However, the extent of slaughtering outside official channels is not fully understood and needs to be investigated. To account for the practice of home slaughter, a second scenario was considered assuming that 25% and 17% of sheep and goat populations are slaughtered every year, respectively. As expected, this second scenario resulted in both increased direct and indirect costs for these species (
Findings of the present study indicate that CE imposes a substantial economic impact on Iran. Reduction of human and livestock infection through implementation of CE control programs is necessary to reduce the economic burden of CE on the country. Cost-benefit analysis of different control programs is now possible in light of present knowledge on the economic losses associated with CE in Iran. However, because comparing monetary costs in different countries with different socioeconomic statuses is often not optimal, a complementary analysis of the non-monetary burden of CE is recommended to compare CE burden in different geographical regions. In addition, evaluation of the non-monetary burden of the disease and measurement of cost per DALY averted by the control campaigns is recommended. Therefore, a paper evaluating CE-associated DALYs in Iran is currently in preparation. This is the first study to evaluate monetary losses due to human and livestock CE in Iran. However, additional research is needed to improve CE monetary burden estimates and to develop uniform methodologies for assessment
STROBE checklist.
(DOC)