Hydatidosis in camels (Camelus dromedarius) and their potential role in the epidemiology of Echinococcus granulosus in Iran

Ultrasonographic verification of hepatic hydatidosis in a female dromedary camel: a case report

This report describes for the first time, the antemortem diagnosis of hydatidosis in dromedary camel based on the WHO informal working groups on echinococcosis guidelines of echinococcosis classification. The case was admitted at the University Veterinary Hospital, Qassim University, Saudi Arabia, with a history of progressive weight loss and decreased appetite for the past 4 months. Alterations in hematobiochemical parameters included leukopenia, neutropenia, decreased hematocrit percent, red blood cells count and hemoglobin concentration, hypoproteinemia, hypoalbuminemia, hyperglobulinemia, hyperglycemia and azotemia. Ultrasonographically, multiple cysts were imaged within the hepatic tissue containing anechoic fluid and fibrin tags. Ultrasound-guided aspiration of a cyst revealed a clear non-turbid fluid. Ultrasonographic diagnostic is recommended for the work-up of cystic lesions of camel liver suspected to be due to Echinococcus granulosus.

Pathological Findings and Oxidative Stress Status Associated with Hydatidosis in Dromedary Camels

(1) Background: Cystic echinococcosis is a zoonotic helminth disease that causes severe economic losses. The study aimed to assess the prevalence and viability of cystic echinococcosis in examined camels. In addition, assessing the histological, morphological, oxidative, and antioxidant state related to the cystic echinococcosis infection; (2) Methods: The study was performed on 152 slaughtered dromedary camels between March and September 2022 at El-Basatin abattoir in Cairo Governorate, Egypt; (3) Results: The results revealed that the prevalence of hydatidosis was 21.7% in slaughtered camel and the highest infection rate observed in lungs was 87.87%, while it was 9% in livers. Camels' liver infections were rare, whereas their lung infections were more common. By comparing to non-infected camels, the level of MAD was significantly increased with hydatid cysts infection, while the level of GSH, SOD and CAT was significantly decreased. Histopathological section of camel cyst revealed layered membranes surrounded by a zone of cellular infiltration and an outermost fibrous tissue reaction. In addition, there was evidence of atelectasis, emphysema, hemorrhage, congestion, and fibrosis in the surrounding tissues. Nonetheless, the degeneration and necrosis of hepatocytes and other pathological alterations in liver cyst sections were remarkably comparable to those seen in the lungs. Furthermore, calcification was detected.

Occurrence and Phylogenetic Description of Cystic Echinococcosis Isolate from Egyptian Camel (Camelus Dromedarius)

Cystic echinococcosis is one of the most significant cyclo-zoonotic diseases of major economic and public health significance worldwide. The current study was carried out to determine the epidemiological profile of cystic echinococcosis as well as to investigate its molecular and phylogenic status from one-humped camel (Camelus dromedarius) in the southern region of Egypt. In the present work, 110 camels freshly slaughtered at Daraw abattoirs, Aswan governorate were inspected for the presence of Hydatid cysts (HCs) visually and manually by palpation and incision, over a period of one year (June, 2018 - May, 2019). Furthermore, fourteen fertile hydatid cyst samples were collected from lungs of slaughtered camels. DNA extraction from two fertile samples was successfully achieved followed by phylogenetic analysis on two mitochondrial genes (cox1and nad1). Out of 110 camels slaughtered 11 (10 %) were found harboring hydatid cysts. The infection was found to prevail throughout the year, with the highest peak encountered in winter (45.5 %). The lungs were the most frequently infected organs (72.7 %) with liver cysts occurring at a significantly lower rate (27.3 %). The mean value of total protein, glucose, urea, cholesterol, magnesium, potassium, copper and creatinine was higher in cystic fluid from camels as compared to cattle. Blast and phylogenetic analysis on sequenced genes showed the presence of Echinococcus intermedius, originally the pig genotype (G7) in camels for the first time in Egypt. To the best of our knowledge, the current research provides a description of the current epidemiological and molecular situation of camel hydatidosis in the southern region of Egypt. Furthermore, the current results may have significant implications for hydatid disease control in the studied region.

Echinococcoses in Iran, Turkey, and Pakistan: Old Diseases in the New Millennium

Echinococcosis is considered a cosmopolitan zoonosis caused by different species of small taeniid tapeworms of the genus Echinococcus and is regarded as a neglected zoonosis. Cystic and alveolar echinococcoses are endemic diseases of Tibetan, Pamir, and Iranian plateaus. All of the countries within the Iranian plateau are affected by echinococcosis. Pakistan, Turkey, and Iran are the three most populous countries of the region, in which echinococcosis is highly endemic. The three neighboring countries share strong cultural and socioeconomic ties. The present study aimed to provide a broad review of the status of cystic and alveolar echinococcosis, summarizing the current knowledge about geographical distribution, molecular epidemiology, and transmission dynamics of Echinococcus granulosus sensu lato and Echinococcus multilocularis in this region. Additionally, we aimed to understand disease burden and risk factors as basic requirements for establishing a surveillance system and planning prevention and control programs. A considerable body of information is available on different aspects of echinococcosis in this region; however, several information and research gaps need to be filled before planning control programs. None of the countries in the region have an elaborate echinococcosis control program. Effective control programs require multi/intersectoral coordination within a One Health approach with a long-term political and administrative commitment and enhanced international collaboration among the three countries.

The global status and genetic characterization of hydatidosis in camels (Camelus dromedarius): a systematic literature review with meta-analysis based on published papers

Hydatidosis is a potential zoonotic helminthic disease affecting a broad spectrum of mammals, including humans, worldwide. The current review was conducted to investigate the genotypic status and prevalence of hydatid disease in camels across the world. For the purpose of the study, the articles addressing the worldwide prevalence of hydatidosis in camels were searched in several English language databases. The search process resulted in the inclusion of 122 papers. Based on the data presented in the reviewed articles, the pooled prevalence of hydatid disease in camels across the world was measured at 23.75% (95% CI 20.15-27.55). Moreover, the subgroup analysis demonstrated significant differences in the overall prevalence of hydatidosis among camels based on year, geographic area, climate parameters, camel population, gender, infected organ, fertility rate of the cyst and laboratory diagnostic technique. Furthermore, the Echinococcus granulosus genotypes identified in camels with hydatidosis included G1, G2, G3, G1-G3, G5, G6, G7, G6-G7 and G6-G10, with G6 being the most common genotype throughout the world. The data obtained from the current study are central to the better conceptualization of the biological and epidemiological characteristics of E. granulosus s.l. genotypes around the world, which can be helpful in the planning and adoption of more comprehensive control strategies.

In-House Developed ELISA Indicates High Prevalence of Anti-Echinococcus granulosus IgG in Sheep Population-An Update from Pakistan

Cystic echinococcosis (CE) is a World Health Organization (WHO)-listed neglected tropical farm economy jeopardizing and public health concern disease. This study was aimed at furnishing sero-epidemiological baseline data of CE in sheep in Pakistan, where data are non-existent. For this purpose, two sheep-rich provinces of Pakistan were selected, and 728 sheep sera were collected using probability proportional to size (PPS) statistical technique. Epidemiological information was recorded on a questionnaire for the estimation of potential risk factors. The serum samples were analyzed for IgG antibodies against Echinococcus granulosus using an in-house-developed EgAgB-based ELISA kit. The overall seroprevalence recorded was 21.98% (160/728) in the tested sheep, suggesting higher seropositivity in sheep from Punjab (23.73%) as compared to Khyber Pakhtunkhwa (KPK) (19.04%). The overall apparent prevalence observed by this ELISA method was almost similar to the calculated true prevalence (21.77%). Prevalence was significantly different (p < 0.05) among sheep from different districts. Higher prevalence was found in females (22.54%, OR 1.41), age group > 5 years (29.66%, OR 1.64), crossbreeds (42.85%, OR 2.70), and sheep with pasture access (25.96%, OR 3.06). Being in age group > 5 years and having pasture access were the factors significantly associated with seropositivity (p < 0.05). This study provides serological evidence of E. granulosus infection in sheep and can be used as a model for ante-mortem screening of the sheep globally.

Environmental, climatic and host population risk factors of human cystic echinococcosis in southwest of Iran

BACKGROUND

Cystic echinococcosis (CE), a worldwide zoonotic disease, is affected by various biological and environmental factors. We investigated dog/livestock populations, climatic and environmental factors influencing the distribution of human CE cases in Fars province, southwest Iran.

METHODS

We mapped the addresses of 266 hospitalised CE patients (2004-2014) and studied the effects of different temperature models, mean annual rainfall and humidity, number of frosty days, slope, latitude, land covers, close proximity to nomads travel routes, livestock and dog densities on the occurrence of CE using geographical information systems approach. Data were analyzed by logistic regression.

RESULTS

In the multivariate model predicting CE, living in an urban setting and densities of cattle and dogs were the most important CE predictors, sequentially. Dry (rained) farm, density of camel and sheep, close proximity to nomads travel routes, humidity, and slope also were considered as the determinants of CE distribution, when analyzed independently. Slope had a negative correlation with CE while temperature, frost days and latitude were not associated with CE.

CONCLUSIONS

In our study, an urban setting was the most important risk factor and likely due to a combination of the high density of key life cycle hosts, dogs and livestock, a large human susceptible population and the high number of abattoirs. Farmland and humidity were highly suggestive risk factors and these conditions support the increased survival of Echinococcus granulosus eggs in the soil. These findings support the development of strategies for control of disease. More research is needed test optimal interventions.

Genotyping and phylogenetic analysis of hydatid cysts isolated from livestock in Bushehr province, Iran

Hydatid cyst is one of the parasitic zoonoses caused by infection with the larval stage of Echinococcus granulosus tapeworm. The spread of this parasite is global and is of great importance in terms of public health. To date, ten different species of this parasite have been identified that differ in characteristics such as life cycle, epidemiology and pathogenesis. The purpose of this study was to determine the genotype and phylogenetic relationship of hydatid cysts isolated from livestock of Bushehr province, Iran. About 62 samples of hepatic and pulmonary hydatid cysts were collected from slaughtered animals. DNA extracted by phenol-chloroform method was amplified by PCR using primers specific for the cox1 gene. The PCR products of 50 samples were sequenced and analyzed using BioEdit software and compared with sequences in the GenBank. The phylogenetic tree was drawn using Neighbor Joining tree-NJ method, and its reliability was evaluated. Sequencing results showed that out of 50 sequenced samples, 43 samples had the genotype of Echinococcus granulosus and 7 samples had the genotype of Taenia hydatigena. By drawing a phylogenetic tree, all 43 hydatid cyst samples belonged to G1 strain. The predominance of G1 strain of hydatid cyst in livestock of Bushehr province shows the main role of this genotype in establishing the life cycle of parasite in this region and if the genotype of the parasite in dogs and humans is determined, then these findings can be used to disrupt the life cycle of the parasite and reduce the human infections.

Genetic Characterization of Hydatid Cysts of Different Intermediate Hosts

Cystic echinococcosis is an important cosmopolitan parasitic zoonosis that causes public health and economic problems in Egypt. The present study was undertaken to identify genotypes of hydatid cyst (HC) DNA isolated from different animal isolates and to identify the genotype of secondary hydatid cysts (HCs) developed in rabbits experimentally infected with camel HC for detection of any genetic mutation. In the present study, we extracted DNA from the germinal layers of 8 HCs collected from 3 camels, 1 cattle, 1 sheep and 3 donkeys in addition to 3 secondary HCs collected from rabbits experimentally infected with camel HC. PCR amplification of the ITS1 gene of all examined samples showed an amplified DNA band at 1115 bp. The partial nucleotide sequences of the ITS1 gene of all isolates were aligned and compared with the reference sequences of the genotypes G1–G8 in GenBank. The camel and rabbit samples were identified as Echinococcus canadensis genotype 6 (G6), while the cattle and sheep samples belonged to E. granulosus sensu stricto (G1). The donkey isolates belonged to E. equines (G4). Alignment of the ITS1 partial nucleotide sequences of the camel HCs and rabbit secondary HCs isolates with the G6 partial nucleotide sequence in GenBank was performed. Both camel HCs and rabbit secondary HCs isolates exhibited the same sequence identity matrix, which indicated the absence of mutation in the rabbit secondary HCs. It can be concluded that camel and rabbit samples were identified as E. canadensis (G6), the cattle and sheep samples belonged to E. granulosus sensu stricto (G1) and donkey isolates belonged to E. equines (G4). No mutation occurred during HCs transmission from camel to rabbit.

Zoonotic implications of camel diseases in Iran

Approximately 60% of all human pathogens and 75% of emerging infectious diseases are zoonotic (of animal origin). Camel zoonotic diseases can be encountered in all camel-rearing countries. In this article, all studies carried out on camel zoonotic diseases in Iran are reviewed to show the importance of camels for public health in this country. More than 900 published documents were systematically searched to find relevant studies from 1,890 until late 2018. The collected articles were classified according to the aetiological agents. In this study, 19 important zoonotic diseases were reported among Iranian camels including listeriosis, leptospirosis, plague, Q fever, brucellosis, campylobacteriosis, tuberculosis, pasteurellosis, clostridiosis, salmonellosis, Escherichia coli infections, rabies, camelpox, Middle East respiratory syndrome coronavirus, Crimean-Congo haemorrhagic fever, echinococcosis, cryptosporidiosis, toxoplasmosis and dermatophytosis, most of which belong to bacterial, viral, parasitic and fungal pathogens, respectively. Results show that camels are one of the most important sources of infections and diseases in human; therefore, continuous monitoring and inspection programs are necessary to prevent the outbreak of zoonotic diseases caused by this animal in humans.

A Review of Zoonotic Pathogens of Dromedary Camels

Dromedary, or one-humped, camels Camelus dromedarius are an almost exclusively domesticated species that are common in arid areas as both beasts of burden and production animals for meat and milk. Currently, there are approximately 30 million dromedary camels, with highest numbers in Africa and the Middle East. The hardiness of camels in arid regions has made humans more dependent on them, especially as a stable protein source. Camels also carry and may transmit disease-causing agents to humans and other animals. The ability for camels to act as a point source or vector for disease is a concern due to increasing human demands for meat, lack of biosafety and biosecurity protocols in many regions, and a growth in the interface with wildlife as camel herds become sympatric with non-domestic species. We conducted a literature review of camel-borne zoonotic diseases and found that the majority of publications (65%) focused on Middle East respiratory syndrome (MERS), brucellosis, Echinococcus granulosus, and Rift Valley fever. The high fatality from MERS outbreaks during 2012-2016 elicited an immediate response from the research community as demonstrated by a surge of MERS-related publications. However, we contend that other camel-borne diseases such as Yersinia pestis, Coxiella burnetii, and Crimean-Congo hemorrhagic fever are just as important to include in surveillance efforts. Camel populations, particularly in sub-Saharan Africa, are increasing exponentially in response to prolonged droughts, and thus, the risk of zoonoses increases as well. In this review, we provide an overview of the major zoonotic diseases present in dromedary camels, their risk to humans, and recommendations to minimize spillover events.

An analysis of common foodborne parasitic zoonoses in slaughtered sheep and cattle in Tehran, Iran, during 2015-2018

Background and Aim:

Cystic echinococcosis, Echinococcus granulosus, and liver flukes, such as Fasciola spp. and Dicrocoelium dendriticum, are important parasitic zoonoses, where they able to cause significant veterinary, medical, and economic problems. The present study was carried out to obtain the updated knowledge on the frequency of hydatidosis, fasciolosis, and dicrocoeliosis in the slaughtered sheep and cattle.

Materials and Methods:

Information were collected from meat inspection records using systematically visual inspection, palpation, and incision of the visceral organs in the industrial abattoir in Tehran, the capital of Iran, between February 1, 2015, and January 31, 2018. For an analysis of the data, SPSS version 16 was applied.

Results:

The hydatidosis infection in sheep and cattle was 2.48% and 2.25%, respectively. With respect to liver flukes, 0.62% and 0.25% sheep and cattle were infected by Fasciola spp., respectively; furthermore, 2.86% sheep and 0.79% cattle were positive for D. dendriticum.

Conclusion:

The findings will provide considerable awareness for the future monitoring and control of these potentially important infections.

Hydatidosis of Camels and Sheep Slaughtered in Aswan Governorate, Southern Egypt

Background: Hydatidosis is an infection caused by the cystic larval stage of Echinococcus granulosus. This disease is a zoonotic disease has a worldwide distribution and common in developing and undeveloped countries. Objectives: The objective of the present study is to studying the infection rate and predilection seats of hydatid cyst affections among slaughtered food animals in Aswan Governorate, southern Egypt and study the effect of age and sex of infected slaughtered animals on the infection with hydatid cyst. Also, study the effect of seasonal variations in the infection with hydatid cyst among slaughtered animals. In addition, the macroscopic examination, microscopic examination, scanning electron microscopy and histopathological studies for the collected hydatid cyst are examined. Methods: This investigation was carried out from August 2015 to July 2016 in two main slaughterhouses in Aswan Governorate to study the hydatidosis in camels and sheep. By routine meat inspection, hydatid cyst count and characterization was conducted. Findings: A total of 2080 camels and 674 sheep were examined. Of these, 173 (8.32%) camels and 3 (0.45%) sheep were found to harbour one or more hydatid cysts. Female and older age slaughtered animals were more susceptible to infection with these metacestode than males and younger animals. Hydatid cyst infection in slaughtered animals is most commonly found in lung followed by liver while mixed infection in both lung and liver was found only in camel. Hydatid cyst in slaughtered camels was higher in autumn followed by winter, while hydatid cyst in slaughtered sheep was found only in autumn season. Fertile cysts in lung and liver of slaughtered camels was 83.4% and 30% respectively. While the fertility of hydatid cyst in infected lung and liver of sheep was 100%. Main conclusions: This study reported that slaughtered animals were infected with relatively high infection rate of hydatid cyst may be due to the presence of socio-economic conditions favourable for the disease and maintenance of high level of infection. So must design governmental control programs against hydatidosis to minimize the infection rate in Aswan Governorate and ensure effective protection not only for animal population but also for humans at risk of contracting the infection.

Cystic echinococcosis in marketed offal of sheep in Basrah, Iraq: Abattoir-based survey and a probabilistic model estimation of the direct economic losses due to hydatid cyst

Cystic echinococcosis (CE) is a highly endemic parasitic zoonosis in Iraq with substantial impacts on livestock productivity and human health. The objectives of this study were to study the abattoir-based occurrence of CE in marketed offal of sheep in Basrah province, Iraq, and to estimate, using a probabilistic modelling approach, the direct economic losses due to hydatid cysts. Based on detailed visual meat inspection, results from an active abattoir survey in this study revealed detection of hydatid cysts in 7.3% (95% CI: 5.4; 9.6) of 631 examined sheep carcasses. Post-mortem lesions of hydatid cyst were concurrently present in livers and lungs of more than half (54.3% (25/46)) of the positive sheep. Direct economic losses due to hydatid cysts in marketed offal were estimated using data from government reports, the one abattoir survey completed in this study, and expert opinions of local veterinarians and butchers. A Monte-Carlo simulation model was developed in a spreadsheet utilizing Latin Hypercube sampling to account for uncertainty in the input parameters. The model estimated that the average annual economic losses associated with hydatid cysts in the liver and lungs of sheep marketed for human consumption in Basrah to be US$72,470 (90% Confidence Interval (CI); ±11,302). The mean proportion of annual losses in meat products value (carcasses and offal) due to hydatid cysts in the liver and lungs of sheep marketed in Basrah province was estimated as 0.42% (90% CI; ±0.21). These estimates suggest that CE is responsible for considerable livestock-associated monetary losses in the south of Iraq. These findings can be used to inform different regional CE control program options in Iraq.

Parasitic diseases of camels in Iran (1931-2017) - a literature review

Parasitic diseases of camels are major causes of impaired milk and meat production, decreases in performance or even death. Some camel parasites also represent a threat to human health. About 171,500 one-humped camels (Camelus dromedarius) and 100-300 two-humped camels (Camelus bactrianus) live in Iran. Knowledge of the biodiversity of their parasites is still limited. The present review covers all information about camel parasitic diseases in Iran published as dissertations and in both Iranian and international journals from 1931 to February 2017. Ten genera of Protozoa (Trypanosoma, Eimeria, Cryptosporidium, Toxoplasma, Neospora, Sarcocystis, Besnoitia, Theileria, Babesia and Balantidium), 48 helminth species detected in the digestive system, including three species of Trematoda, four species of Cestoda, and 41 species of Nematoda, as well as helminths from other organs - Echinococcus spp., Dictyocaulus filaria, Thelazia leesei, Dipetalonema evansi and Onchocerca fasciata - have so far been described in Iranian camels. Furthermore, 13 species of hard ticks, mange mites, the myiasis flies Cephalopina titillator and Wohlfahrtia magnifica, and immature stages of the Pentastomida Linguatula serrata have also been reported from camels of Iran. Camel parasitic diseases are a major issue in Iran in terms of economics and public health. The present review offers information for an integrated control programme against economically relevant parasites of camels.

Global Distribution of Alveolar and Cystic Echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.

Sero-epidemiology of cystic echinococcosis (Echinococcus granulosus) in the livestock of Oman

A cross-sectional serological survey of cystic echinocossis was carried out on 2802 randomly collected sera of camels (n=706), cattle (n=687), goats (n=701) and sheep (n=708) from all governorates of Oman. The samples were analysed by in house indirect ELISA (iELISA) using Echinococcus granulosus antigen B (EgAgB) of naturally infected camels. The overall percentage of antibodies against EgAgB was found to be 14.6%. The highest percentage of positive was observed in sera from camels (22.4%) followed by cattle (12.9%), sheep (12.2%) and goats (10.9%). The highest percentage of seropositivity was observed in females (15.4%) as compared to male animals (10.6%). The imported livestock were found more seropositive (15.2%) as compared to local (14.7%) and crossbred livestock (14.1%). The highest exposure was observed in animals with the age group of above 5years (18.3%) followed by the age group of up to 2years (15.1%,) and those between 2 and 5years (12.4%). The univariate analysis has indicated that camels (OR:2.33, CI 1.74, 3.14), cattle (OR:1.21, CI 0.87, 1.67), sheep (OR:1.12, CI 0.81, 1.55) were more likely to test positive than goats. Furthermore, females (OR: 1.53, CI 1.11, 2.11) were more likely to test seropositive. Sera from animals above 5years of age (OR:1.58, CI 1.25, 2.01) and between 2 and 5years old (OR:1.30, CI 0.98, 1.71) were found more likely to test seropositive than those up to 2years of age. The multivariable analysis at individual level indicated that camels (OR: 2.07, CI 1.66, 2.56, p<0.001) and female (OR: 1.43, CI 1.04, 1.98, p=0.030) were more likely to acquire CE. At herd level, the final multivariable model indicated that herds located in Dofar and Musandam (OR: 4.48, CI 2.69, 7.45, p<0.001), in areas receiving seasonal rains (OR: 2.54, CI 1.09, 5.90, p<0.001) and practicing transhumance (OR: 4.22, CI 1.84, 9.65, p<0.001) and sedentary (OR: 2.07, CI 1.38, 3.12, p=0.001) farming system were more likely to acquire CE in Oman. The study documents the serological evidence of CE in livestock of Oman and a carefully planned control program should be devised after further epidemiological and molecular investigations in the intermediate and final hosts.

Echinococcus granulosus in humans associated with disease incidence in domestic animals in Kermanshah, west of Iran

Hydatidosis is one of the important zoonotic diseases that cause considerable economic losses and public health problems worldwide. This study was conducted to determine the prevalence Echinococcus granulosus in people and slaughtered animals in Kermanshah province, west of Iran. Hospitals data and meat-inspection records in Kermanshah abattoir were used in this study. A total number of 32,130 slaughtered livestock (7000 cattle, 19,950 sheep and 5180 goats) was inspected in the 3-year period and overall 2043 (6.35 %) were infected. The highest and lowest prevalence was recorded in cattle and goats, respectively. In human, Cystic echinococcosis affected more females (54 %) than males (46 %) with a 1.17 male to female ratio. Rate of disease in urban and rural regions were 46 and 54 %, respectively. The youngest and the oldest patient operated were 7 and 87 years old, respectively, and the age group 21-40 years (41.2 %) were the most affected. A significantly higher number of hydatid cysts were recorded in the liver than in other sites. The ratio of hepatic hydatidosis to pulmonary hydatidosis was 2.46. The results showed that hydatidosis is of great importance in this area and serious attention is needed to prevent and control the disease.

Echinococcus granulosus: Epidemiology and state-of-the-art of diagnostics in animals

Diagnosis and detection of Echinococcus granulosus (sensu lato) infection in animals is a prerequisite for epidemiological studies and surveillance of echinococcosis in endemic, re-emergent or emergent transmission zones. Advances in diagnostic approaches for definitive hosts and livestock, however, have not progressed equally over the last 20 years. Development of laboratory based diagnostics for canids using coproantigen ELISA and also coproPCR, have had a huge impact on epidemiological studies and more recently on surveillance during hydatid control programmes. In contrast, diagnosis of cystic echinococcosis (CE) in livestock still relies largely on conventional post-mortem inspection, despite a relatively low diagnostic sensitivity especially in early infections, as current serodiagnostics do not provide a sufficiently specific and sensitive practical pre-mortem alternative. As a result, testing of dog faecal samples by coproantigen ELISA, often combined with mass ultrasound screening programmes for human CE, has been the preferred approach for monitoring and surveillance in resource-poor endemic areas and during control schemes. In this article we review the current options and approaches for diagnosis of E. granulosus infection in definitive and animal intermediate hosts (including applications in non-domesticated species) and make conclusions and recommendations for further improvements in diagnosis for use in epidemiological studies and surveillance schemes.

Genetic characterization of Echinococcus granulosus from a large number of formalin-fixed, paraffin-embedded tissue samples of human isolates in Iran

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, presents an important medical and veterinary problem globally, including that in Iran. Different genotypes of E. granulosus have been reported from human isolates worldwide. This study identifies the genotype of the parasite responsible for human hydatidosis in three provinces of Iran using formalin-fixed paraffin-embedded tissue samples. In this study, 200 formalin-fixed paraffin-embedded tissue samples from human CE cases were collected from Alborz, Tehran, and Kerman provinces. Polymerase chain reaction amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 gene were performed for genetic characterization of the samples. Phylogenetic analysis of the isolates from this study and reference sequences of different genotypes was done using a maximum likelihood method. In total, 54.4%, 0.8%, 1%, and 40.8% of the samples were identified as the G1, G2, G3, and G6 genotypes, respectively. The findings of the current study confirm the G1 genotype (sheep strain) to be the most prevalent genotype involved in human CE cases in Iran and indicates the high prevalence of the G6 genotype with a high infectivity for humans. Furthermore, this study illustrates the first documented human CE case in Iran infected with the G2 genotype.

A retrospective survey of hydatidosis based on abattoir data in Kermanshah, Iran from 2008 to 2013

A retrospective study was carried out from 2008 to 2013 to estimate the prevalence of hydatidosis in ruminants slaughtered at the Kermanshah municipal abattoir, in western Iran. A total number of 663,633 livestock (393,585 sheep, 81,080 goats and 188,968 cattle) slaughtered in the 5-year period and overall 9,524 (1.43 %) livers and 13,147 (1.98 %) lungs were condemned. The lungs were more frequently infected with hydatid cysts than the livers in all animal species. The average prevalence of hydatidosis was 2.7 % in this area. The prevalence of Echinococcus granulosus infection recorded in the present study was generally lower than those reported from other regions of Iran. Greater awareness among farmers, destruction of organs containing hydatid cysts, prevention of access of dogs to raw offals and implementation of national rabies control program could be responsible factors. The results showed a significant difference (p < 0.001) in the prevalence of hydatidosis among studied animals with higher prevalence in cattle than sheep, with the lowest prevalence recorded in goats. However the annual prevalence of liver and lung condemnations due to hydatidosis was decreased in some years, but the overall trend had a variable pattern in the prevalence of hydatidosis over the study period. Data showed a significant seasonal pattern for hydatidosis in all studied animals. Liver and lung condemnations due to hydatidosis were higher in the fall for sheep and cattle, whereas in goats were higher in summer. This could be attributed to various factors such as sources of slaughtered animals, changes in management practice and ecological factors. The current results suggest that a systematic investigation that lead to a disease control strategy is required to reduce the economic and public health consequences of hydatidosis. In addition, the present survey provides baseline data for the future monitoring of this potentially important parasitic disease in the region.

Survey of hydatidosis infection in slaughtered camel (Camelus dromedarius) in Tabriz area, Northwest Iran

Hydatid Disease is the name given to the condition caused by the zoonotic tapeworm Echinococcus granulosus. The tapeworm spends most of its adult life in the intestine of its definitive host, namely canids and in particular the dog. The tapeworm eggs become voided in the canids' faeces and as a result of ingesting the eggs, infection passes to the intermediate host, commonly herbivores while grazing. However, humans can become accidentally infected and hydatid cysts may develop throughout the body. During April 2010-February 2014, a total 198 camels, which had been sent to the abattoir, the daily number of hydatid infected livers and lungs of camels slaughtered at Tabriz abattoir were recorded. To be sure about the validity of recorded data, observed data were collected daily. Approximately 29 (14.64 %) of camels were infected according to this survey. Age wise, the prevalence of infection in young animals (under the age of 5 years) was 4 (2.02 %), whereas in animals between 5 and 10 years and over, the prevalence of infection was 11 (5.55 %) and 14 (7.07 %) respectively. Sex wise, female animals had a higher prevalence with 17 (19.76 %) cases in camels, whereas in the males, there were 12 (10.71 %) cases in camels. There was a notable difference found in our study between male and female animals (P < 0.05). Infections were recorded in two visceral organs with the Lungs having the highest prevalence in camels, and the liver had low infected in camels. The results of this study suggest that infection of camels with hydatid cyst is common in Tabriz, Iran and that this may constitute economic and health problems in the meat industry.

Infected hydatid cysts bacteria in slaughtered livestock and their effects on protoscoleces degeneration

Background:

The protoscoleces of fertile hydatid cysts are considered as major risks in surgery and producing secondary cysts if rupture the cyst during operation and, cause infecting the dogs with adult worm if eaten by this animal. Bacterial infection of the hydatid fluid can lead to sterilization of the cyst.

Objectives:

The aim of this study was to determine the bacterial infection rate of livestock hydatid cysts in Hamedan, Iran, and test the isolated bacteria effects on viable protoscoleces, in vitro.

Materials and Methods:

A total of 5709 slaughtered livestock were inspected to detect the presence of hydatid cysts. The hydatid fluid of all cysts was cultured separately to isolate and identify the bacteria. The effect of isolated bacteria was tested on viable protoscoleces in culture tubes, in vitro. The culture tubes were observed and examined under a light microscope every two hours for 24 hours, and then, after 36 and 48 hours.

Results:

Infected cysts were found in 74% of animals in Hamedan (46% were calcified and the bacteria was isolated from 52%) and 62% in Borujerd. The isolated bacteria in the infected cysts were as follows: Escherichia coli, E. blattae, Klebsiella pnoumoniae, Proteus mirabilis, Enterobacter aerogenes, coagulase-positive and coagulase-negative Staphylococci, Pseudomonas aeruginosa and Edwardsiella tarda. The protoscoleces incubated with the isolated bacteria totally degenerated, but 55% of the protoscoleces in the control groups were intact and viable even after one week.

Conclusions:

This study indicated a high percentage of cysts bacterial infections in two provinces of Iran. The common isolated bacteria were E. coli and Klebsiella. The isolated bacteria degenerated the protoscoleces during short-time incubation, in vitro.

Hydatidosis of camel (Camelus dromedarius) at Jijiga municipal abattoir, Eastern Ethiopia: prevalence, associated risk factors and financial implication

A cross-sectional study was conducted from November 2010 to May 2011 to estimate the prevalence of camel hydatidosis, associated risk factors and financial loss in Jijiga municipal abattoir, Somali Regional State, Eastern Ethiopia. Accordingly, of the total 400 inspected camel, 92 (23 %) camels and 109 organs were positive for hydatid cyst with the highest proportion recorded in lung (56 %) followed by liver (33.9 %), spleen (7.3 %) and kidneys (2.8 %). The prevalence of hydatidosis significantly varied among age categories (P < 0.05), sex (P < 0.05) and body condition score (P < 0.05) of camels. Hence, there is higher likelihood for occurrence of camel hydatidosis among the older age groups (OR 1.8, 95 % CI 1.2, 3.3), in female camels (OR 2.8, 95 % CI 1.7, 4.7) and in poor body conditioned camels (OR 4.1, 95 % CI 2.2, 7.9) than younger camels, males and camels with good body condition score, respectively. Of the total 288 examined cysts for fertility and viability, 59.7 % (172/288) were fertile while the rest 24.0 % (69/288) cysts were sterile. Of the 172 fertile cysts 69.8 % (n = 120) were viable and 30.2 % (n = 52) were non-viable. The rest 16.3 % (47/288) cysts were found dead. It was also observed that the pulmonary and hepatic cysts had fertility rate of 63.7 % (116/182) and 57.4 % (54/94), respectively. The total annual direct financial loss recorded in this study as result of organs condemnation due to hydatid cyst, was 12,147.75 Ethiopian birrs ($714.57 or $7.77/camel). If this value could be extrapolated to the infected camel population of the region, financial loss due to hydatidosis could be enormous. In conclusion, this study showed the importance of hydatidosis and the associated direct financial loss due to the condemnation of organs affected by hydatid cyst in the study area.

Prevalence of liver fluke infections in slaughtered animals in Lorestan, Iran

Fasciola spp. and Dicrocoelium dendriticum as liver flukes, contaminate ruminants and other mammalian extensively and cause major diseases of livestock that create considerable economic losses. This retrospective study has been done to evaluate contamination rate of slaughtered animals with fasciolosis and dicrocoeliosis at Lorestan abattoirs. In this survey, prevalence rate of fasciolosis and dicrocoeliosis in slaughtered animals in a 3-year period (2010-2013) has been analyzed. A total of 356,605 livestock including 265,692 sheep and 90,913 goats were slaughtered in the 3-year period and overall 39,613 (11.1 %) livers were condemned. Fascioliasis and dicrocoeliosis were responsible for 6.3 and 4.8 % of total liver condemnations in this period, respectively. Fasciola spp. and D. dendriticum infection in sheep (7.1 and 5.6 %, respectively) were considerably higher than goats (3.9 and 2.6 %, respectively). The annual prevalence rates showed a significant decline in the fasciolosis and dicrocoeliosis infection in goats (p < 0.001). Data showed significant seasonal pattern for distomatosis in sheep and goats (p < 0.001). Liver condemnations due to fasciolosis were prevalent in sheep and goats slaughtered during spring and autumn, respectively, whereas dicrocoeliosis were common in spring season for both sheep and goats. This survey provides baseline data for the future monitoring of these potentially important parasitic infections in the region.

Liver condemnation and economic losses due to parasitic infections in slaughtered animals in Iran

The prevalences of parasitic infections responsible for the condemnation of liver during meat inspection, and their economic implication were estimated in slaughtered animals in Iran. The liver organ was examined for the presence of parasitic lesions during meat inspection in cattle, camel, buffalo, sheep and goat. The parasitic agents observed in the condemned livers of these animals were Fasciola spp., Dicrocoelium dendriticum, Cysticercus tenuicollis and hydatid cyst. The average percentages of liver condemnation for three years period by Fasciola spp., D. dendriticum, Cysticerci and hydatid cyst were 2.12, 2.71, 0.04, and 2.88 %, respectively. The mean prevalence of Fasciola spp. in cattle, sheep, goat, camel and buffalo was 4.32, 1.85, 1.56, 1.31 and 9.31 %, respectively and the mean prevalence of D. dendriticum in those animals were 3.65, 2.66, 2.19, 5.09 and 3.90 %, respectively. Also, the mean prevalence of Cysticerci and hydatid cyst were 0.13 and 3.72 % in cattle, 0.04 and 2.85 % in sheep, 0.05 and 2.40 % in goat, 0.02 and 8.22 % in camel and 0.001 and 5.48 % in buffalo, respectively. The most contributing parasites to marketable liver condemnation were hydatid cyst in sheep, goat and camel and Fasciola spp. in cattle and buffalo, and the average annual cost for condemned livers was 8.2 million USD.

Molecular genotyping of Echinococcus granulosus from dromedaries (Camelus dromedarius) in eastern Iran

With the aim of genotyping Echinococcus granulosus cysts found in Iranian dromedaries (Camelus dromedarius), 50 cysts of E. granulosus were collected from five geographical regions in Iran. Cysts were characterized using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the internal transcribed spacer 1 (ITS1) gene and sequencing fragments of the genes coding for mitochondrial cytochrome c oxidase subunit 1 (cox1). Morphological criteria using rostellar hook dimensions were also undertaken. The present results have shown that 27 out of 50 E. granulosus cysts (54%) were determined as the G1 strain, and the other (46%) were determined as the G6 strain. The molecular analysis of the ITS1 region of ribosomal DNA corresponded with the morphological findings. Because of its recognized infectivity in humans, the G1 genotype is a direct threat to human health and its presence in Iranian dromedaries is of urgent public health importance.

A systematic review of the epidemiology of echinococcosis in domestic and wild animals

BACKGROUND

Human echinococcosis is a neglected zoonosis caused by parasites of the genus Echinococcus. The most frequent clinical forms of echinococcosis, cystic echinococcosis (CE) and alveolar echinococcosis (AE), are responsible for a substantial health and economic burden, particularly to low-income societies. Quantitative epidemiology can provide important information to improve the understanding of parasite transmission and hence is an important part of efforts to control this disease. The purpose of this review is to give an insight on factors associated with echinococcosis in animal hosts by summarising significant results reported from epidemiological studies identified through a systematic search.

METHODOLOGY AND PRINCIPAL FINDINGS

The systematic search was conducted mainly in electronic databases but a few additional records were obtained from other sources. Retrieved entries were examined in order to identify available peer-reviewed epidemiological studies that found significant risk factors for infection using associative statistical methods. One hundred studies met the eligibility criteria and were suitable for data extraction. Epidemiological factors associated with increased risk of E. granulosus infection in dogs included feeding with raw viscera, possibility of scavenging dead animals, lack of anthelmintic treatment and owners' poor health education and indicators of poverty. Key factors associated with E. granulosus infection in intermediate hosts were related to the hosts' age and the intensity of environmental contamination with parasite eggs. E. multilocularis transmission dynamics in animal hosts depended on the interaction of several ecological factors, such as hosts' population densities, host-prey interactions, landscape characteristics, climate conditions and human-related activities.

CONCLUSIONS/SIGNIFICANCE

Results derived from epidemiological studies provide a better understanding of the behavioural, biological and ecological factors involved in the transmission of this parasite and hence can aid in the design of more effective control strategies.

The monetary burden of cystic echinococcosis in Iran

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.

Molecular characterization of livestock and human isolates of Echinococcus granulosus from south-west Iran

Hydatidosis is an important public health problem in several parts of Iran. The aim of this molecular study is to investigate Echinococcus granulosus genotypes as the causative agents of hydatidosis in the south-west of Iran (Khuzestan province). In this study, isolates of 334 hydatid cysts were collected from the liver and lungs of 141 sheep, 104 cattle, 84 goats and 5 human cases. DNA was extracted and examined by nested polymerase chain reaction (PCR) of ribosomal DNA (rDNA) internal transcribed spacer 1 (ITS1) and restriction fragment length polymorphism (RFLP)-PCR. In addition, fragments of genes coding for ITS1 were sequenced. The results of RFLP-PCR analysis revealed the presence of the G1 genotype in all human, cattle, goat and sheep isolates. Furthermore, no camel strain (G6) was detected among all samples in the regions studied. The molecular findings indicate that the predominant genotype involved in E. granulosus transmission in south-west Iran is the common sheep strain (G1 genotype), which occurs in human, cattle, sheep and goat populations. In conclusion, these results may have important implications for hydatid disease control in the areas studied.

Epidemiological aspects of cystic echinococcosis in slaughtered herbivores in Sari abattoir, North of Iran

A study was conducted to assess the ruminants' hydatidosis in Mazandaran Province, Northern Iran. A total, 1,799 sheep, 985 goats and 362 cattle slaughtered at Sari industrial slaughter house were examined for hydatid cyst infection. The results indicated that 65.2% of sheep, 37.8% of goats and 40.1% of cattle were infected. The liver and lung infection rate in sheep were 18.8 and 4.3%, goats 17.2 and 12.6% and cattle 44.1 and 7.6%, respectively. The study showed that 766 (45.3%) out of 1,691 infected animals had moderate degree of infection. Geographical zone survey indicated that 1,381 (89.2%) out of 1,546 sheep and goats infected with hydatid cyst were non-indigenous and originated from north-eastern provinces of Iran. On the contrary, 50.3% of infected cattle originated from Mazandaran Province (indigenous).

An abattoir-based study of hydatidosis in the dromedary (Camelus dromedarius) in Mashhad, Iran

A 6-year retrospective study based on abattoir records was carried out to determine the prevalence of hydatidosis in dromedaries in Khorasan province in north–eastern Iran. Between 20 March 2004 and 19 March 2010, 25,255 dromedaries were slaughtered in the study area and the livers of 2791 (11.1%) and the lungs of 3289 dromedaries (13.2%) were discarded due to hydatidosis. The annual prevalence of liver condemnations due to hydatidosis decreased from 24.1% in 2004–2005 to 13.3% in 2009, and finally to 6.8% in 2010. The corresponding features for lung condemnation due to hydatidosis were relatively higher than liver, declining from 28.7% in 2004–2005 to 14.9% in 2009, and finally to 7.1% in 2010. Liver and lung condemnations due to hydatidosis were significantly higher in the spring. This could be attributed to various factors such as sources of slaughtered animals, changes in management practice and ecological factors. The present survey provides baseline data for the future monitoring of this potentially important parasitic disease in the region.

Molecular characterization of human and animal Echinococcus granulosus isolates in Isfahan, Iran

Cystic hydatid disease (CHD) is one of the most important zoonotic diseases in different parts of Iran. While it causes major health problem, there is limited information about its transmission cycles and reservoirs of human infection. Therefore we aimed to characterize the existence Echinococcus granulosus cysts in humans and animals in the province of Isfahan, central region of Iran. We collected hydatid cysts from the liver and lungs of patients who underwent surgery procedure and also cysts were obtained from domestic animals at slaughterhouses. DNA was extracted from the protoscoleces and examined by polymerase chain reaction (PCR) of rDNA internal transcribed spacer1 (ITS1-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). In addition, fragments of the genes coding for mitochondrial cytochrome c oxidase subunit 1 (CO1) and NADH dehydrogenase 1 (ND1) were sequenced. Among the two different identified strains/genotypes (sheep and camel), the sheep strain was shown to be the most common genotype of E. granulosus affecting humans, sheep, cattle, goats and occasionally camels. Nine out of 26 camel samples were infected with sheep strain. However the camel genotype was observed in humans, camels and cattle. Seventeen out of 26 camel isolates, 6 out of 31 human and 5 out of 14 cattle samples were infected with the camel genotype. The camel genotypes had PCR and RFLP patterns which were different from the PCR and RFLP patterns of the rest of isolates (sheep strain). The results of this study showed that the 'camel' strain was actual source of infection to humans which circulates between intermediate hosts including camels and cattle, and it confirms the camel-dog transmission cycle in Isfahan.

An abattoir-based study on the prevalence and economic losses due to cystic echinococcosis in slaughtered herbivores in Ahwaz, south-western Iran

A 10-year (1998–2008) retrospective study was carried out to investigate the prevalence and long-term trend of hydatid disease in slaughtered herbivores in the large complex abattoir of Ahwaz (the capital of Khuzestan province, south-western Iran). A total of 3,583,417 animals including 2,815,982 sheep, 427,790 goats and 339,645 cattle were inspected macroscopically for hydatid cysts in the 10-year period, and overall 155,555 (4.24%) livers and 228,172 (6.37%) lungs were condemned. Cystic echinococcosis (CE) was responsible for 36.08% and 48.04% of total liver and lung condemnations, respectively. The prevalence of pulmonary hydatid disease in sheep, goats and cattle was 2.22, 5.43 and 6.99%, respectively; on the other hand, the prevalence of hepatic hydatid disease for those animals was 1.26, 2.57 and 2.80%, respectively. Data showed an overall downward long-term trend for CE in all livestock slaughtered during the study period (P < 0.01). Lung condemnation due to CE was significantly more common than liver condemnation for each animal separately (P < 0.001). The prevalence of liver and lung hydatidosis in sheep was significantly lower than that in other livestock (P < 0.001). The prevalence of hydatid disease recovered from the sheep, cattle and goats varied in different seasons, but there was no statistical difference between various seasons. The odds ratio of lung and liver condemnations due to hydatidosis showed a slightly different pattern in some years; however, the overall declining trend was still observed. The total annual economic loss incurred due to hydatidosis in all ruminants slaughtered at Ahwaz municipal abattoir was estimated to be US$459,659.6, based on the market prices in the year 2008. This number corresponds to a loss of US$300,620.4 for cattle, US$123,490.0 for sheep and US$35,549.2 for goats. The current results provide baseline data for the future monitoring of this potentially important disease in the region, and also suggest that a thorough investigation leading to a disease control strategy is required to reduce the economic and public health consequences of CE.

Human cystic echinococcosis in Yasuj District in Southwest of Iran: an epidemiological study of seroprevalence and surgical cases over a ten-year period

Cystic echinococcosis is a zoonotic infection of humans and domestic animals caused by the larval stages of the cestode Echinococcus granulosus. Cystic echinococcosis is one of the most important zoonotic diseases in Iran, where human cases are frequently reported from different regions of the country. The objective of this study was to determine the sero-epidemiological and surgical cases of human hydatidosis in the Yasuj district, a region in southwest of Iran. Serum samples were taken from 500 individuals attending Yasuj health centers. Anti-hydatid cyst antibody was checked by enzyme-linked immunosorbent assay (ELISA), using antigen B. Moreover, retrospective studies were carried out using local hospital records of CE patients between 1997 and 2006. Results of the sero-epidemiological study showed that 36 out of 500 cases (7.2%) have antibody against hydatid cyst. Of these 36 cases, 49.6% were women and 50.4% were men. The highest rate of infection was recorded in individuals aged between 30 and 39 years. Hospital records showed that during the 10 years, 105 cases of hydatidosis were admitted in Yasuj hospitals. Of all cases, 70 (66.7%) were women and 35 (33.3%) were men. Hepatic cyst was recorded in 81% of the cases where nephrotic cysts were the second most prevalent ones. Recurrence of the disease was noted in 14.3% of all cases. Results of this study demonstrated that hydatidosis is an important endemic disease, with a nearly constant prevalence rate during the last 10 years, in Yasuj district in Iran. Further studies are needed to investigate the reasons for high rate of surgical cases in housewives and striking prevalence of hydatidosis in a specific (30-40 years) age group.

Hydatidosis of slaughtered animals in Ngorongoro district of Arusha region, Tanzania

A study on the prevalence of hydatidosis in cattle, goats and sheep was carried out in Ngorongoro district of Arusha region, Tanzania. A 4-years data records from four slaughter slabs were retrieved and analysed. In addition, meat inspection was done in the same slaughter slabs for nine months and 64 households were interviewed to assess the community awareness on hydatidosis. Results showed the overall prevalence of hydatidosis to be 47.9%. Species prevalence of 48.7%, 34.7% and 63.8% in cattle, goats and sheep respectively was recorded. Of 174 cysts examined in cattle, 37 (21.3%) were fertile, 126 (72.4%) were sterile and 11 (6.3%) were calcified. Out of 215 goats and 67 sheep cysts examined, 52 (24.7%) and 26 (38.8%) were fertile, 138 (64.2%) and 38 (56.7%) were sterile, 24 (11.2%) and 3 (4.5%) were calcified respectively. The higher percentage of fertile hydatid cysts in sheep and goats coupled with the practice of backyard slaughter of sheep and goats suggests that, these animals could be important intermediate hosts for the maintenance of the domestic life cycle of E. granulosus in the locality. Questionnaire survey revealed that 17.2% of the respondents were aware of hydatidosis but non of them were knowledgeable on its transmission. Up to 84.4% of the respondents had domestic ruminants and donkeys, while 89.1% had dogs. Of the households with dogs, only 19.3% had their dogs dewormed at least once in life time. Most of the households (87.7%) had their dogs managed freely and 77.2% of the respondents reported school children to be the closest friends of dogs in the family. The prevalence of E. granulosus infection in wildlife and the possible relationship of the domestic cycle to the sylvatic cycle operating in the same area are unknown and need to be studied.

Present situation of echinococcosis in the Middle East and Arabic North Africa

Echinococcosis is one of the major zoonotic parasitic diseases in the Middle East and Arabic North Africa from Morocco to Egypt. Both cystic and alveolar echinococcosis has been reported from these areas. However, cystic echinococcosis is more prevalent and has been reported from all countries in the Middle East and Arabic North Africa. Alveolar echinococcosis is less prevalent and has been reported only from Iran, Turkey, Iraq and Tunisia. Present situation of echinococcosis in dogs and other definitive hosts, animal intermediate hosts and humans in the Middle East and Arabic North Africa has been reviewed. Echinococcus granulosus is highly prevalent in Iran, Turkey, Iraq, Morocco, Tunisia, and Libya. In the Levant countries, the cystic echinococcosis is also highly endemic. In Oman, it is endemic with low prevalence and a very low level in Cyprus. Various surveys have indicated that hydatid cysts are commonly found in sheep, cattle, goats and camels throughout the Middle East and Arabic North Africa. Sheep are the most infected animals of these regions. Most of studies on human have been focused on surgical reports although several population studies have been performed using serological and imaging techniques. Human cystic echinococcosis (CE) is prevalent in the Middle East and Arabic North Africa. It is hyper endemic in Iran, Turkey, Iraq, Jordan, Morocco, Libya, Tunisia, and Algeria, and endemic in Egypt. Studies on the strain specificities of E. granulosus in the Middle East revealed sheep strain (G1) present in sheep, goats, cattle, camels and humans, and the camel strain (G6) in camels, sheep, cattle as well as humans. Dog/sheep strain seems to be more prevalent in the foregoing regions in documented reports from Iran and Jordan. However, a strain of E. granulosus, which resembles the horse strain (G4) strain, has been reported from Jordan. Strain specifications of E. granulosus in Arabic North Africa showed that sheep/dog strain (G1) have been reported from Tunisia and Libya both from humans and animals. However, in Egypt the human cases reported are of camel/dog strain.