The Burden of Parasitic Food Borne Diseases in the World and in Iran

Among the Foodborne diseases (FBD), foodborne parasitic diseases (FPD) are considered as a serious etiology for morbidity and mortality. Foodborne Disease Burden Epidemiology Reference Group (WHO), has defined the following parasites as FPD: Giardia, Entamoeba, Cryptosporidium spp., Toxoplasma gondii, Fasciola spp, Opisthorchis spp, Clonorchis spp, Echinococcus spp, Taenia solium (Cysticercosis), Trichinella spp, Anisakis simplex and Ascaris lumbricoides. Giardia has the highest global prevalence (median=10.8%), followed by Entamoeba (median=4.3%), and Cryptosporidium (median=4.0%). Foodborne outbreaks of cryptosporidiosis associated with the consumption of fresh produce have been reported mainly in the U.S. and in northern Europe. The prevalence of cryptosporidiosis varies from 1-3% in industrialized countries, and up to 10% in developing countries. Human toxoplasmosis encompasses the global burden as 190, 000 new cases annually, resulting in the loss approximately 1.2 million DALYs. Consumption of undercooked meat results in 50% or more cases of toxoplasmosis. Worldwide, about 56.2 million people were infected with food borne trematodes (FBT) in 2005, 7.9 million presented severe sequelae and 7158 died. FBT result in approximately 665, 000 DALYs a year. Clonorchis sinensis and Opistorchis viverrini are mainly found in East and South East Asia and the Asia Pacific regions. The number of people infected with liver fluke is 25 million with 10 million for O. viverrini, 15 million for C. sinensis and about 1 million for O. felineus. Estimates of human fasciolosis vary from 2.4-17 million people and people at risk at 91.1×106. Heterophyids infect 40 to 50 million people worldwide and paragonimiasis may infect 20 million people worldwide. The global burden of cystic echinococcosis is estimated 1 million DALYs and prevalence ranges from 1% to 7% with annual incidences of up to 32 cases per 100,000. Incidence for alveolar echinococcosis is estimated as 18,000 globally each year resulting in about 660,000 DALYs. DALY for cysticercosis is calculated as 503,000 DALYs. As for human trichinellosis from 1986 to 2009 there were 65818 cases and 42 deaths recorded globally and all of the cases were from 41 countries. Ascariasis was estimated to cause 2,700 Deaths, and account for 1,315,000 DALYs. There have been 15,000 to 20,000 total cases of anisakiasis and 12-100 cases per year for diphyllobothriasis in Asia.In Iran, fascioliasis is emerging as an important chronic disease of humans, especially in the northern province of Gilan (where outbreaks in 1989 and 1999 involved 7000 and 10,000 cases, respectively) and, more recently, in the western province of Kermanshah. Recent estimates of the prevalences of ascariasis lie between just <0.1%. Approximately 1% of all admissions to surgical wards are attributable to cystic echinococcosis, which is still considered endemic, but only few cases of alveolar echinococcosis have been recorded. The overall annual cost of cystic echinococcosis 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.Out of a total of 16,592 stool samples, 226 samples were positive for Entamoeba histolytica/E. dispar cysts in northern, central, and southern Iran. 92.1% of isolates were E. dispar and 7.9% were E. histolytica or mixed infections. The last nationwide estimation (in 2005) for giardiasis shows 10.9%, which is much lower nowadays. 2.40% of children were positive for Cryptosporidium oocysts in Iran. As for toxoplasmosis, higher prevalences near 60-75% have been reported in the northern parts of Iran, while lower seropositivity as 20-35% has been reported in the north-west, central and southern regions. Unfortunately, regarding protozoa infection in Iran, less attention had been paid in terms of DALY estimation.

Keywords:

Foodborne diseases , Parasites , Prevalence , Incidence , Iran