Epidemiology and strain characteristics of Echinococcus granulosus in the Benghazi area of eastern Libya

Molecular characterization and haplotypes of hydatid cyst isolates collected from humans and ruminants in Setif Province (northeast of Algeria) based on mitochondrial cytochrome C oxidase subunit 1 (mt-CO1) gene sequences

Cystic echinococcosis (CE) is a disease that can be transmitted from animals to humans, caused by the metacestode of Echinococcus granulosus. The disease has significant health and economic impacts worldwide, particularly in endemic areas. The study aimed to evaluate the prevalence of hydatid cysts in ruminants (cattle and sheep) (n = 2060) from the Setif Province of Algeria using microscopy. The results showed that hydatid cysts were detected in 9.6% (198/2060) of ruminants, with a higher prevalence in cattle (16.8%; 56/333) compared to sheep (8.2%; 142/1727). Molecular techniques were used to analyze a subset of animals consisting of 30 sheep and 4 cattle. Specifically, a fragment of the mitochondrial cytochrome c oxidase subunit 1 (mt-CO1) gene was sequenced and compared to sequences from seven humans from the same region. The results indicated that all isolates were identified as E. granulosus sensu stricto. Haplotype analysis identified 19 E. granulosus s.s. haplotypes arranged like a star, with the dominant haplotype (Hap04) at the center. Hap04 has been assigned a total of 17 positives, including positives from sheep, cattle, and two humans. This study is noteworthy for being the first to use a molecular approach to human and ruminant echinococcosis in Setif, a significant breeding region in Algeria.

[Hydatid cyst sampling by FTA Card method for characterizing Echinococcus granulosus sensu lato in Algeria. Preliminary results]

Introduction and objectives

Cystic echinococcosis is highly endemic in Algeria and constitutes a major socio-economic problem. Typing the species of the Echinococcus granulosus sensu lato complex circulating in cattle requires the use of a hydatid cyst sampling method adapted to difficult field conditions (high heat and humidity, long transport time). The FTA Card method currently constitutes an effective means of preserving biological samples before their molecular analysis. In the present study, the FTA Card method was used in the collection of hydatid cysts to identify the species of E. granulosus sensu lato circulating in ruminants (intermediate hosts) in eastern Algeria.

Material and methods

A PCR was carried out for 41 samples of hydatid cysts taken from six slaughterhouses in eastern Algeria, targeting the cox1 mitochondrial gene. PCR products were visualized by electrophoresis in a 1% agarose gel.

Results and conclusion

The results of the molecular analysis of all hydatid cyst samples confirmed the presence of E. granulosus sensu stricto in sheep, cattle and camels. The ubiquitous nature of the G1 genotype has been demonstrated. The use of FTA Card sampling is an efficient and simple method to obtain a biological sample in order to characterize the species of E. granulosus sensu lato in Algeria. The good preservation of the DNA in this matrix will make it easier to obtain new molecular data from difficult regions. The identification of the species of the E. granulosus sensu lato complex involved in the biological cycle is an essential prerequisite for the implementation of control measures, since different host species participate in their evolutionary cycle. The characterization of E. granulosus genotypes is essential to define an appropriate control strategy against cystic echinococcosis.

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.

Global Prevalence of Echinococcosis in Goats: A Systematic Review and Meta-Analysis

Echinococcosis is a foodborne parasitic zoonosis caused by the larvae of Echinococcus. This disease can affect goats and other mammals. In this study, a systematic review and meta-analysis for echinococcosis in global goats were performed based on the following five databases (China National Knowledge Infrastructure [CNKI], VIP Chinese Journal Database, Wanfang Data, PubMed, and ScienceDirect). In total, 108,197 samples were collected. The global prevalence of echinococcosis in goats was identified to be 10.85% (3217/108,197). The prevalence of echinococcosis in goats was 6.16% (1369/22,208) and 13.27% (874/5932) in South America and Africa, respectively. The prevalence of echinococcosis in goats before 2010 (9.76%; 112/713) was significantly higher than that from 2010 to 2014 (1.44%; 45/32,145) or after 2014 (2.95%; 154/3889). The prevalence of echinococcosis in goats aged <12 months (4.48%; 70/2911) was higher than that in goats aged ≥12 months (2.88%; 36/819). We also investigated the effects of geographical factors and climates on the prevalence of echinococcosis in goats. The results showed that the prevalence of echinococcosis was higher in the areas with high altitude and cold climate. This meta-analysis indicated that echinococcosis was ubiquitous in goats. Thus, we should improve the feeding conditions for goats, and strengthen the control measures of echinococcosis epidemic in goats, with the aims of reducing the economic losses of animal husbandry and providing protection for humans in the aspects of food security and health.

Echinococcus granulosus sensu lato Genotypes in Different Hosts Worldwide: A Systematic Review

INTRODUCTION

The aim of this study was to develop a synthesis of the evidence available regarding verified E. granulosus sensu lato (s.l.) genotypes in different species worldwide.

MATERIAL AND METHODS

A systematic review was performed including studies concerning genotypes of E. granulosus s.l. without language or genotyped method restriction, published between 1990 and 2020. A systematic search was carried out in Trip Database, BIREME, SciELO, LILACS, IBECS, PAHO-WHO, EMBASE, PubMed, Scopus, and WoS. Variables of interest were year of publication, country, number of samples, and hosts; genotypes, molecular marker, haplotypes and molecular biology techniques used. Descriptive statistics were applied.

RESULTS

2411 articles were analyzed, however 135 met the selection criteria, representing 8643 liver and lung samples. Of the samples selected 24% were human, the remaining samples pertained to non-human animal hosts; cattle and sheep prevailed with 28.6% and 26.6% of the studied samples, respectively. The reported evidence is mainly from Iran, Turkey, Argentina, China and Chile; with 50, 11, 6, 6 and 5 studies, respectively, published between 1992 and 2020 [most frequently during 2015-2020 (76/135 studies; 56.3%)]. The mitochondrial gene cox1 was generally sequenced and informative (91.8%). Genotypes most frequently identified were E. granulosus sensu stricto (s.s.) (83.2%).

CONCLUSIONS

Based on this overall evidence, it can be concluded that publications related to genotypes of E. granulosus s.l. are heterogeneous. E. granulosus ss accounts for the vast majority of the global burden of E. granulosus s.l. worldwide. Further studies including larger number of cases and adequate internal validity are required to specify the distribution of genotypes in various host species.

TRIAL REGISTRATION

PROSPERO CRD42018099827.

Prevalence and Molecular Characterization of Cystic Echinococcosis in Livestock Population of the Malakand Division, Khyber Pakhtunkhwa, Pakistan

Cystic echinococcosis (CE) is a neglected zoonotic disease prevalent in Pakistan, but the genetic diversity of the cestode is largely unexplored in the country. This study investigated the molecular epidemiology of CE infecting the livestock population of the Malakand division, Khyber Pakhtunkhwa, Pakistan. A total of 1,200 livestock, including buffaloes, cattle, goats, and sheep, were examined for echinococcosis from November 2017-2018 at different slaughterhouses in the Malakand division. Hydatid cysts were collected from different organs, and hydatid cyst fluid (HCF) was examined microscopically and used for DNA extraction. The LSU (rrnl) and NAD1 genes were amplified and sequenced. The overall prevalence of CE was 17% (204/1,200), including cows (21.7%), buffaloes (17.4%), goats (10%), and sheep (9.6%). The infection was relatively more prevalent among males (17%) than females (16.9%) and animals of older age (>5 years) (p = 0.710). Liver (63.2%) and lungs (25%) were more affected as compared to kidneys (6.8%) and heart (4.9%). HCF analysis indicated that 52.0% of the cysts were sterile and (48.0%) were fertile. Sequencing and phylogenetic analyses confirmed 80.0% of the isolates as Echinococcus granulosus sensu stricto (G1-G3) in all animal species, while Echinococcus equinus (G4) and Echinococcus ortleppi (G5) were present in buffaloes. The present study concluded that CE is prevalent in the livestock population of Malakand. Besides E. granulosus s. s. (G1-G3), E. ortleppi genotype (G5) and E. equinus (G4) in livestock were also reported.

Cystic echinococcosis: an emerging zoonosis in southern regions of Khyber Pakhtunkhwa, Pakistan

Background

Cystic echinococcosis (CE) is one of the principal causes of economic loss to the livestock industry because of its morbidity and mortality of food-producing animals and condemnation of important visceral organs. Pakistan being an agricultural country having an extensive livestock sector, is mostly practiced by poor people, which has a fundamental role in the economy. The present study was aimed to conduct a cross-sectional survey and PCR based confirmation of Echinococcus granulosus in sheep, goats, cows, and buffaloes from southern regions (three districts: Lakki Marwat, Bannu, and Karak) of Khyber Pakhtunkhwa, Pakistan. During the study, a total of 2833 animals were examined randomly including; sheep (n = 529), goats (n = 428), cows (n = 1693), and buffaloes (n = 183). Hydatid cysts were collected and examined for the presence of protoscoleces using microscopy. Detection of DNA was performed by using PCR and two mitochondrial genetic markers namely; NAD-1 and COX-1 were amplified.

Results

The overall prevalence of CE was found to be (9%) among the examined animals. The hydatid cyst infection was highly prevalent in buffaloes (12%), followed by sheep (10%), cows (9%), and goats (5.1%). Cystic echinococcosis was more prevalent (10%; 96/992) in district Lakki Marwat followed by district Bannu (9%; 112/1246) and Karak (7%; 39/595). Female animals were more likely to be infected with CE (11.6%) than male animals (5.3%) (p = 0.001). Similarly, the infection was higher in the older group of animals as compared to younger (p = 0.001). Mostly (52.2%; n = 129) of hydatid cysts were found in the liver, while (64.4%; n = 159) cysts of the infected animals were infertile. PCR based identification confirmed the presence of E. granulosus sensu stricto (s.s) in the study area.

Conclusion

Cystic echinococcosis was found to be highly prevalent in southern regions of Khyber Pakhtunkhwa and could be a potential threat to human health. Moreover, molecular sequencing and phylogenetic analyses should be carried out in future to identify the prevailing genotype (s) of E. granulosus s.s.

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.

Cystic Echinococcosis of Camels: 12S rRNA Gene Variation Revealed Changing Pattern of Genetic Diversity Within Echinococcus granulosus sensu lato in the Middle East and North/Sub-Saharan Africa

Cystic echinococcosis (CE) is one of the most widespread zoonotic diseases, with considerable public health and economic importance. Camels play a significant role in transmission cycle of Echinococcus granulosus especially, in the Middle East and North Africa (MENA). The present study aimed to identify the genetic variation and haplotype distribution of camel isolates of E. granulosus sensu lato using all existing E. granulosus mitochondrial DNA data from camels in different parts of the world. Sequence data from 1,144 camel isolates of E. granulosus s.l. available in the NCBI GenBank including 57 camel hydatid cysts collected in central Iran were used to analyze the nature of genetic variation within the camel isolates of E. granulosus s.l. in MENA region. Fifty-seven camel isolates were also PCR-sequenced on mitochondrial 12S rRNA gene. Haplotype network analysis revealed seven different haplotypes clustered into four major groups. E. intermedius G6 was identified as the most commonly represented genotype in camels followed by G1. Mitochondrial 12S rRNA gene sequence analysis on 57 camel isolates identified three different genotypes, including E. intermedius/G6 (35/57, 61.4%), E. granulosus sensu stricto/G1-G3 (21/57, 36.8%) as well as one isolate identified as E. ortleppi/G5 (1/57, 1.8%). The number of base substitutions per site over 420 positions of partial 12S rRNA gene sequences were shown as 0.000 and 0.004 for E. intermedius (G6) corresponding to the Middle East and sub-Saharan isolates, respectively. Camel isolates of E. granulosus in the MENA region present moderate genetic diversity (Hd = 0.5540–0.6050). The Middle East isolates demonstrated a more diverse population than the North/sub-Saharan isolates, where six out of seven 12S rRNA haplotypes were identified in the former region. E. intermedius (G6 genotype) was shown to be the most common species in the world camel population. In conclusion, camels showed to be an important intermediate host species in the MENA region with different patterns of genetic variation between the Middle East and Africa.

Molecular characterization of Echinococcus granulosus in livestock of Al-Madinah (Saudi Arabia)

Echinococcus granulosus is the causative agent of cystic echinococcosis, which has serious impacts on human and/or animal health, resulting in significant economic losses. Echinococcus granulosus comprises a number of intra-specific variants or strains at the genetic level. In Saudi Arabia, few studies were performed on genetic variations in Echinococcus species. Therefore, the present study aimed to investigate the phenotypic and genetic characterization of hydatid cysts harboured by sheep and camels in Al-Madinah Al-Munawarah. Samples of hydatid cysts were collected from local sheep (n = 25) and camels (n = 8). The morphological criteria of protoscoleces were investigated. To investigate the molecular characterization, random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR), single-stranded conformation polymorphism (SSCP) were carried out. DNA was extracted from individual fertile cysts and subjected to RAPD-PCR analysis (using five arbitrary primers) and PCR amplification of cytochrome c oxidase I (cox1) and 12S ribosomal ribonucleic acid (12S rRNA) genes. The PCR products were subjected to SSCP analysis for genetic discrimination in E. granulosus isolates. In addition, partially sequencing of the mitochondrial DNA cox1 genes was achieved for assessing the phylogenetic positions of collected isolates using some global published sequence data of cox1 genes. The rostellar hooks of camel and local sheep isolates show remarkable variability in their dimensions. Five distinct SSCP patterns were identified in the 12S rRNA gene, showing intraspecific variations in E. granulosus of camels and local sheep. Sequencing of (cox1) genes of both local sheep and camels exhibit high similarity with those of the same gene (E. granulosus sensu stricto) published in NCBI BLAST.

Comparison of molecular and morphological characterization and haplotype analysis of cattle and sheep isolates of cystic echinococcosis

Cystic echinococcosis is a zoonotic disease and the second most common foodborne parasitic infection worldwide. The aim of the present study was to investigate genetic variations in G1 and G3 genotypes of Echinococcus granulosus sensu stricto and determine the morphological differences between two genotypes. In total, 119 cystic samples were collected from 48 cattle and 71 sheep in slaughterhouses in four cities in three geographical regions of Turkey regions (Ankara, Central Anatolio region; Ordu, Black Sea region; and Adana, Mersin, Mediterranean region). For molecular characterization of the G1 and G3 genotypes, two gene regions (the complete mt-cox1 gene sequence and partial mt-nad5 gene sequence) were amplified. Haplotype analysis was conducted to determine the nucleotide differences between the complete sequences of the mt-cox1 gene for 47 samples. In addition, morphological parameters in protoscoleces of fertile cysts were measured to determine the relationship between the genotypes and morphometry. According to the obtained genotype and morphometry results, there were no statistically significant differences between the genotypes in terms of the number of hooks, total lengths of large and small hooks, blade lengths of large and small hooks, and widths of small hooks, although there was a statistically significant difference in large hook width (p > 0.05).

Variabilities of hydatidosis in domestic animals slaughtered at Cairo and Giza abattoirs, Egypt

Aim

The effect of some variables on hydatidosis in animals slaughtered at Cairo and Giza abattoirs was investigated and the influence on serum biochemical parameters, antioxidant enzymes, and histopathological lesions caused by these parasites as a consequence was estimated.

Materials and Methods

The effect of some variables on hydatidosis in 397 sheep, 401 cattle, 435 buffaloes, and 341 camels slaughtered at Cairo and Giza abattoirs was investigated, and the influence on serum biochemical parameters, antioxidant activity and histopathological lesions caused by these parasites as a consequence was estimated.

Results

The results revealed that 39 sheep (9.8%), 74 cattle (18.4%), 95 buffaloes (21.8%), and 79 camels (23.25%) were infected. Concerning age variations, 165 young and 232 adult sheep, 215 young and 186 adult cattle, 194 young and 241 adult buffaloes, and 112 young and 229 adult camels were examined. The prevalence of hydatidosis was higher in adult sheep, cattle, and camel; 32 (13.8%), 49 (26.3%), and 56 (24.5%) than the younger ones 7 (4.2%), 25 (11.6%), and 23 (20.5%), respectively. Two hundred and eighty-eight sheep, 171 cattle were examined during winter. However, 109 sheep, 230 cattle were examined during summer. Hydatidosis infection in sheep and cattle was higher in winter 26 (9.01%) and 47 (27.5%) than in summer 13 (11.9%) and 27 (11.7%), respectively. Out of 133 sheep and 128 camels slaughtered in El-Basatin abattoirs, 36 (15.3) and 38 (29.7%) showed higher prevalence than that from El-Warak and El-Moneib abattoirs. Comparing with the non-infected groups, alkaline phosphatase activity decreased in hydatid-infected animals, while cholesterol and liver enzymes activities increased. Total lipid and triglyceride levels decreased in infected camels. Glutathione peroxidase, superoxide dismutase, and catalase decreased in hydatid-infected animals.

Conclusion

The disturbance in the biochemical parameters, liver enzymes, and the antioxidant activities was consistent with the pathological findings that indicated the risk of hydatidosis infection. Finally, this study clarified the variabilities of hydatidosis in Cairo and Giza abattoirs as a starting point for future studies in different regions in Egypt.

Epidemiological survey of echinococcosis in Tibet Autonomous Region of China

BACKGROUND

The echinococcosis is prevalent in 10 provinces /autonomous region in western and northern China. Epidemiological survey of echinococcosis in China in 2012 showed the average prevalence of four counties in Tibet Autonomous Region (TAR) is 4.23%, much higher than the average prevalence in China (0.24%). It is important to understand the transmission risks and the prevalence of echinococcosis in human and animals in TAR.

METHODS

A stratified and proportionate sampling method was used to select samples in TAR. The selected residents were examined by B-ultrasonography diagnostic, and the faeces of dogs were tested for the canine coproantigen against Echinococcus spp. using enzyme-linked immunosorbent assay. The internal organs of slaughtered domestic animals were examined by visual examination and palpation. The awareness of the prevention and control of echinococcosis among of residents and students was investigated using questionnaire. All data were inputted using double entry in the Epi Info database, with error correction by double-entry comparison, the statistical analysis of all data was processed using SPSS 21.0, and the map was mapped using ArcGIS 10.1, the data was tested by Chi-square test and Cochran-Armitage trend test.

RESULTS

A total of 80 384 people, 7564 faeces of dogs, and 2103 internal organs of slaughtered domestic animals were examined. The prevalence of echinococcosis in humans in TAR was 1.66%, the positive rate in females (1.92%) was significantly higher than that in males (1.41%), (χ² = 30.31, P < 0.01), the positive rate of echinococcosis was positively associated with age (χ²_trend = 423.95, P < 0.01), and the occupational populations with high positive rates of echinococcosis were herdsmen (3.66%) and monks (3.48%). The average positive rate of Echinococcus coproantigen in TAR was 7.30%. The positive rate of echinococcosis in livestock for the whole region was 11.84%. The average awareness rate of echinococcosis across the region was 33.39%.

CONCLUSIONS

A high prevalence of echinococcosis is found across the TAR, representing a very serious concern to human health. Efforts should be made to develop an action plan for echinococcosis prevention and control as soon as possible, so as to control the endemic of echinococcosis and reduce the medical burden on the population.

Incidence, Risk Factors, and Epidemiology of Cystic Echinococcosis: A Complex Socioecological Emerging Infectious Disease in Khyber Pakhtunkhwa, Province of Pakistan

Cystic echinococcosis is a serious zoonotic disease caused by Echinococcus granulosus species complex. The current study is the first attempt to determine the level of infection in domestic livestock and to explore the CE-related knowledge and awareness among livestock farmers in different districts of Khyber Pakhtunkhwa, province of Pakistan. A total of 1297 animals were examined for hydatid cysts including 538 cows, 428 buffaloes, 208 sheep, and 123 goats, at different slaughter houses in different districts of Khyber Pakhtunkhwa in 2 years from September 2015 to September 2017. For epidemiological investigations, prevalence in association with various factors (climate, age, and gender), organ specificity, types of cysts (fertile, sterile, or calcified), and viability of cysts parameters was recorded. Basing on the results obtained, areas with high prevalence were selected for further follow-ups and administration of questionnaires to the farmers and dog owners, to provide baseline data about this parasitic disease and to identify potential areas of emergence with correspondence animal and of public health significance. The finding of this study revealed the presence of CE in livestock of KP, Pakistan. The prevalence of hydatid cysts was the highest in buffaloes (15.88%) followed by cows (15.79%), sheep (15.38%), and goats (3.25%). Our investigation revealed close relationship between prevalence and animal age and gender in different months of the year. These findings also showed the highest prevalence of hydatid cysts in liver (63.49%), followed by lungs (23.80%) and mesentery (2.64%). Fertile and viable cysts were observed in all animal species except goats. The highest percentage of fertile and viable cysts was reported from the liver and lungs of sheep. For evaluation of risk factors, a total of 384 respondents were investigated. The results of current study revealed that 97.9% of farmers are not familiar with CE and transmission of this infection from dogs to human and livestock. The present study shows that CE will continue to be of medical and veterinary importance in Pakistan.

Epidemiological study of Echinococcus granulosus in sheep in the Gharb plain (North-West of Morocco)

Hydatidosis is considered endemic in Morocco and caused serious health problems in ruminants. The aim of this research is to present an epidemiological study on echinococcosis in sheep. The study was carried out between April 2016 and May 2017. A total number of 1600 sheeps was examined via autopsy for Echinococcus granulosus in various slaughterhouses in the Gharb plain of Morocco. The Results of the study showed that the prevalence of cystic echinococcosis was 7.63%. The infection was not significant among sheep which age is < 1 year (2.67%), while it increases among those which age is from 1 to 3 years old (8.63%). It also grows significantly among sheep which age is over 3 years old (11.71%). Parasitized at 62%, the liver is the most affected organ followed by the lungs (38%). Protoscoleces are only found in liquid cysts and contribute to their fertility which is estimated at 66.66% in the liver and 57.74% in the lungs. In addition, the prevalence of calcified cysts is 12.24% in the liver and 21.11% in the lungs. Examination of the fertile cysts revealed a high level of Protoscoleces viability, whether it's in the liver (65.93%) or in the lungs (59.30%). This study also shows how the evolution of echinococcosis is closely linked to sex and age.

Knowledge, Awareness and Practices Regarding Cystic Echinococcosis among Livestock Farmers in Basrah Province, Iraq

Cystic echinococcosis (CE) is an endemic neglected parasitic zoonosis in many of the countries of the Middle East. The disease poses a remarkable economic burden for both animals and humans. In this study, we conducted a questionnaire survey among livestock farmers in Basrah province, southern Iraq, in order to evaluate their knowledge and awareness about CE, and to understand some of the risky practices that could contribute to spread and persistence of such disease. Of the interviewed participants (N = 314), 27.4% owned dogs on their farms. Among farmers owning dogs, 76.7% (66/86) never tied up their dogs, and 43% (37/86) indicated feeding uncooked animal viscera to their dogs. The majority (96.5%) of the farmers indicated that they did not de-worm their dogs at all. Only 9.8% (31/314) of the respondents indicated eating raw leafy vegetables without washing. Added to that, 32% of the interviewees indicated that they source water for domestic use from a river; meanwhile 94.3% (296/314) of them do not boil water before using it for domestic purposes. Half of the interviewed livestock farmers in Basrah were not aware about how humans get infected with CE disease, and 41.4% (130/314) did not even realize that CE is a dangerous disease to human health. Almost one in three of the respondents who owned dogs on their farms viewed de-worming of their dogs as a low priority practice. This study highlights the gap in knowledge and awareness about CE among the study population. Risky practices associated with dog keeping management and food and water handling practices were identified. The insight from this research could be used to improve the delivery of a health education message relevant to cystic echinococcosis control at the human-animal interface in Iraq.

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.

Echinococcus granulosus infection in dogs in Sidi Kacem Province (North-West Morocco)

This study was undertaken in the Province of Sidi Kacem in northwest Morocco between April 2010 and March 2011. The main objective of the study was to determine the prevalence of Echinococcus granulosus (Eg) infection in owned dogs. This province was selected as a case study because of the social conditions, geographic and climatic diversity making it a model representative of many parts of Morocco. The survey was carried out in 23 rural communes and in the 5 municipalities (urban districts) of the Province and sampling was undertaken in randomly selected households. A total of 273 owned dogs comprising 232 from the 23 rural communes (rural dogs) and 41 from the 5 municipalities (urban dogs) were tested. Arecoline hydrobromide purgation was selected as the diagnostic method of choice to enable visualisation of expelled worms by dog owners, thereby imparting messages on the transmission mode of Eg to humans and farm animals. Of the 273 dogs tested, purgation was effective in a total of 224 dogs (82.1%). The overall estimated prevalence of Eg infection was 35.3% (79/224, 95% CI 22.3-47.0%). Dogs inhabiting rural communes were at greater risk of infection (38.0%, 95% CI 31.1-45.3%) than dogs roaming in municipalities or urban areas (18.8%, 95% CI 7.2-36.4%) and the prevalence of infection was higher in those inhabiting rural communes with slaughterhouses (62.7%, 95% CI 48.1-75.9%) than in communes without (29.1%, 95% CI 21.7-37.2%). This first assessment of Eg infection in Sidi Kacem Province indicates a key role of rural slaughterhouses in parasite transmission to dogs.

Knowledge, attitudes and practices with regard to the presence, transmission, impact, and control of cystic echinococcosis in Sidi Kacem Province, Morocco

BACKGROUND

This study is a component of a large research project on five major neglected zoonotic diseases (NZDs) including cystic echinococcosis and was undertaken in the Province of Sidi Kacem over a period of four years (April 2009-March 2013).

METHODS

Questionnaires were administered at community level in a total of 27 communes and visits were made to all of the 10 abattoirs situated in the Province, to collect qualitative data on determinants of transmission for disease in humans and animals. More specifically, community knowledge, attitudes and practices related to cystic echinococcosis were assessed, as well as the extent to which local customs and behaviours may promote transmission. Abattoir infrastructure and practices, and their role in perpetuating disease transmission were also critically evaluated.

RESULTS

The results show that only 50 % of people have heard of the disease, and of those, only 21 % are aware of the dog's role in disease transmission. Sixty-seven per cent of respondents stated that dogs are fed ruminant organs deemed unfit for human consumption. Owned dogs have access to the family home, including the kitchen, in 39 % of households. The extent of this close proximity between humans and animals is even more pertinent when one considers that dogs are omnipresent in the community, with an average of 1.8 dogs owned per household. The unrestricted access of dogs to abattoirs is a huge issue, which further promotes disease transmission.

CONCLUSION

This study would suggest that the high prevalence of cystic echinococcosis in humans and animals in Morocco is largely due to three factors: 1) abundance of dogs 2) engagement in risky behaviour of the local population and 3) poor abattoir infrastructure and practices. This has serious implications in terms of the socio-economic impact of the disease, especially for rural poor communities.

The first morphometric and phylogenetic perspective on molecular epidemiology of Echinococcus granulosus sensu lato in stray dogs in a hyperendemic Middle East focus, northwestern Iran

Background

Hydatidosis is considered to be a neglected cyclo-zoonotic disease in Middle East countries particularly northwestern Iran which is caused by metacestode of tapeworm Echinococcus granulosus sensu lato. Human hydatidosis is a high public health priority in the area, however there is little known from a morphometric and phylogenetic perspective on molecular epidemiology of adult Echinococcus spp. in Iranian stray dogs.

Methods

80 dogs (38 males and 42 females) were collected during June 2013 to April 2014 in northwestern Iran. The isolated parasites from each dog were distinguished by morphometric keys including small, large hook length and blade length. Subsequently, isolates were confirmed by sequencing of mitochondrial cytochrome oxidase subunit 1 gene.

Results

16 (8 males and 8 females) (Prevalence 20 %) out of 80 dogs were infected to genus Echinococcus. With regard to demographic factors, the frequency of parasitism in both male, female adults and their age groups showed no difference (P > 0.05). The phylogenetic analyses of cox1 sequences firmly revealed the 13 sheep strains (G1), one buffalo strain (G3), one camel strain (G6) and one mixed infection. The findings of rostellar hook morphology show an intraspecies variation range among G1 isolates. However, hook measurements in Echinococcus derived from G1 (sheep strain) were not a significant difference from those G6 and G3 strains. Six unique haplotypes were identified containing a high range of diversity (Haplotype diversity 0.873 vs. Nucleotide diversity 0.02).

Conclusions

First presence of camel strain (G6) in this region seems to indicate that potential intermediate hosts play a secondary role in the maintenance of camel-dog biology. Current findings have heightened our knowledge about determination of Echinococcus prevalence, strains of taxonomy and genotypic trait of parasite in Iranian stray dogs which will also help in the development of strategies for monitoring and control of infected stray dogs in the area.

Human Cystic Echinococcosis in the Nalut District of Western Libya: A Clinico-epidemiological Study

Human cystic echinococcosis (CE) is an endemic disease in the Mediterranean area that has not yet been fully documented in western Libya. The present study describes the clinico-epidemiologic profile of CE in western Libya’s Nalut district. From April 2008 to July 2011, 36 cases of CE were confirmed following surgical removal of cysts. The cysts were most frequently found in the liver (61.1%), followed by the lungs (19.4%), kidneys (11.1%), peritoneal cavity (11.1%), and spleen (5.6%). Among the 36 patients, 6 possessed plural cysts and 3 had cysts in 2 organs. Blood samples from this group were examined for the presence of serum anti-hydatid IgG antibodies, which revealed positivity in 25 patients (69.4%). An additional 300 blood samples were collected randomly from the inpatient and outpatient clinics at Nalut Hospital. Twenty-seven samples (9%) were found to be positive for the anti-hydatid IgG antibody among which the prevalence of infection tended to be higher in men (12%) than in women (6%). This study demonstrates that CE is a major parasitic infectious disease of public health significance in Libya, notably in the western part of the country, and that disease awareness needs to be raised nationwide.

Using morphometry of the larval rostellar hooks to distinguish Iranian strains ofEchinococcus granulosus

Human cystic echinococcosis is widely distributed throughout Iran, where sheep, cattle, goats, camels and other animals act as intermediate hosts. It appears that morphometry of the rostellar hooks on the protoscoleces of the causative parasite, Echinococcus granulosus, can be used to separate the strains or variants of the parasite to be found in humans and livestock in Iran. Multivariate statistical procedures, including principal-component analysis and discriminant-function analysis (DFA), were used to explore the morphometric data obtained from the larval hooks of Iranian samples of E. granulosus. Although five physical variables were initially considered, the results of the PCA indicated that just two factors (based on the length of hooks and number of hooks) accounted for 91.6% of the variance observed in the hook measurements. The results of the DFA allowed the correct classification of all the samples. The presence in Iran of the sheep and camel strains of the parasite was confirmed. The sheep strain was the most common variant encountered, being recovered from sheep, cattle, goats, humans and occasionally camels. Most of the metacestode samples from camels and a few of those from cattle (five of 30), sheep (one of 27) and humans (two of 23) were found to be of the camel strain. These results indicate that larval-hook morphology is a valid method for identifying E. granulosus strains in Iran, and one that is potentially useful for epidemiological studies.

The optimum cut-off value to differentiate Echinococcus granulosus sensu stricto from other species of E. granulosus sensu lato using larval rostellar hook morphometry

Cystic echinococcosis caused by Echinococcus granulosus sensu lato is one of the most important helminth zoonoses in the world; it affects both humans and livestock. The disease is endemic in Argentina and highly endemic in the province of Neuquén. Considerable genetic and phenotypic variation has been demonstrated in E. granulosus, and ten different genotypes (G1–G10) have been identified using molecular tools. Echinococcus granulosus sensu lato may be considered a species complex, comprised of E. granulosus sensu stricto (G1–G3), E. equinus (G4), E. ortleppi (G5) and E. canadensis (G6–G10). In endemic areas, the characterization of cystic echinococcosis molecular epidemiology is important in order to apply adequate control strategies. A cut-off value for larval large hook total length to distinguish E. granulosus sensu stricto isolates from those produced by other species of the complex was defined for the first time. Overall, 1780 larval hooks of 36 isolates obtained from sheep (n= 11, G1), goats (n= 10, G6), cattle (n= 5, G6) and pigs (n= 10, G7) were analysed. Validation against molecular genotyping as gold standard was carried out using the receiver operating characteristic (ROC) curve analysis. The optimum cut-off value was defined as 26.5 μm. The proposed method showed high sensitivity (97.8%) and specificity (91.1%). Since in most endemic regions the molecular epidemiology of echinococcosis includes the coexistence of the widely distributed E. granulosus sensu stricto G1 strain and other species of the complex, this technique could be useful as a quick and economical tool for epidemiological and surveillance field studies, when fertile cysts are present.

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.

[Epidemiological profile of 290 cases of human cystic echinococcosis diagnosed in the Mustapha University Hospital (Algiers) from 2006 to 2011]

THE AIM OF THE STUDY

This study reports a series of 290 cases of hydatidosis confirmed by the surgery and/or the imagery with a positive immuno-diagnosis collected between 1st January 2006 and 31 March 2011 at parasitology-mycology laboratory of hospital university center of Mustapha of Algiers. Our aim is to specify, through the listed cases, the epidemiological aspects of this affection and compared with those obtained in two previous Algerian epidemiological investigations carried out, between 1963-1964 and 1966-1975.

PATIENTS AND METHODS

It is a retrospective (2006-2008) and prospective (2008-2011) study. The parasitological diagnosis was carried out by the direct macroscopic and/or microscopic identification of the parasite and indirect diagnosis based on four techniques: passive hemagglutination, Elisa IgG "Echinococcus granulosus", Western Blot IgG "Echinococcus" and electrophoresis.

RESULTS

The study shows that this affection is still prerogative of the young adult. It bring out also in this study that the child of school age (ten years), in particular the boy, pays a heavy tribute. At the child, the preferential pulmonary seat of the hydatic disease is not devoid of risk. At adult, this parasitic disease mainly affect the active woman.

CONCLUSION

Generally, the epidemiological and clinical characteristics join the endemic countries data and confirmed the row of our country among them. The transmission seems as strong as in the past, in spite of a much better social educational level.

A systematic review of the literature on cystic echinococcosis frequency worldwide and its associated clinical manifestations

A systematic literature review of cystic echinoccocosis (CE) frequency and symptoms was conducted. Studies without denominators, original data, or using one serological test were excluded. Random-effect log-binomial models were run for CE frequency and proportion of reported symptoms where appropriate. A total of 45 and 25 articles on CE frequency and symptoms met all inclusion criteria. Prevalence of CE ranged from 1% to 7% in community-based studies and incidence rates ranged from 0 to 32 cases per 100,000 in hospital-based studies. The CE prevalence was higher in females (Prevalence Proportion Ratio: 1.35 [95% Bayesian Credible Interval: 1.16-1.53]) and increased with age. The most common manifestations of hepatic and pulmonary CE were abdominal pain (57.3% [95% confidence interval [CI]: 37.3-76.1%]) and cough (51.3% [95% CI: 35.7-66.7%]), respectively. The results are limited by the small number of unbiased studies. Nonetheless, the age/gender prevalence differences could be used to inform future models of CE burden.

Morphological and molecular characterisation of Echinococcus granulosus from goat isolates in Iran

Hydatidosis is considered to be an important economic and human public health problem in Iran, where a variety of animals act as intermediate hosts. There is limited information about the genotypes of Echinococcus granulosus in goats. In this study, 20 isolates of E. granulosus obtained from goats were characterised by mitochondrial DNA sequencing and morphology of the metacestode. The mitochondrial cytochrome oxidase 1 sequences were evaluated, and the sequence analysis indicated two genotypes within the isolates. 17 samples were identified as G1 strain, and 3 isolates were identified as G6 strain. The results of the morphological studies support the findings of the molecular studies. Two types of rostellar hooks were observed in the goat isolates, in agreement with the strain identification. Type 1 hooks were morphologically similar to those of the common sheep strains, whereas the dimensions of the hooks in type 2 were similar to those normally found in the camel strain. The morphological results suggest that Echinococcus of goat origin is phenotypically similar to either the sheep (G1) or the camel (G6) strains. Further, these results suggest that the transmission of the G1 genotype between sheep and goats seems to be the predominant mode of transmission, but further work is required to verify this.

Worldwide epidemiology of liver hydatidosis including the Mediterranean area

The worldwide incidence and prevalence of cystic echinococcosis have fallen dramatically over the past several decades. Nonetheless, infection with Echinococcus granulosus (E. granulosus) remains a major public health issue in several countries and regions, even in places where it was previously at low levels, as a result of a reduction of control programmes due to economic problems and lack of resources. Geographic distribution differs by country and region depending on the presence in that country of large numbers of nomadic or semi-nomadic sheep and goat flocks that represent the intermediate host of the parasite, and their close contact with the final host, the dog, which mostly provides the transmission of infection to humans. The greatest prevalence of cystic echinococcosis in human and animal hosts is found in countries of the temperate zones, including several parts of Eurasia (the Mediterranean regions, southern and central parts of Russia, central Asia, China), Australia, some parts of America (especially South America) and north and east Africa. Echinococcosis is currently considered an endemic zoonotic disease in the Mediterranean region. The most frequent strain associated with human cystic echinococcosis appears to be the common sheep strain (G1). This strain appears to be widely distributed in all continents. The purpose of this review is to examine the distribution of E. granulosus and the epidemiology of a re-emerging disease such as cystic echinococcosis.

Morphological characteristics of Echinococcus granulosus derived from buffalo in Iran

Cystic echinococcosis is a significant parasitic disease in Iran, where a variety of animals act as intermediate hosts. In this study, 25 isolates of Echinococcus granulosus obtained from water buffalo from various parts of Iran were characterized on the basis of the morphology of the metacestode and the adult worm. The characteristics of protoscoleces from the different studied areas were nearly similar. They showed 2 rows of alternating large and small hooks and their shapes were smooth in outline. In contrast to the protoscoleces, the adult rostellar hooks showed a rough outline. The results showed that the total length, the blade lengths of the large and small hooks and the number of hooks are almost similar to those isolated from sheep but significantly different from those isolated from camels. The growth rates of adult E. granulosus (total worm length, segmentation and maturation) of buffalo origin, at 35 and 41 days post-infection of dogs, were nearly comparable to the common sheep strain. The form of the strobila and the morphology of the reproductive system were also similar to those of sheep origin. This suggests that the common sheep strain (G1) of E. granulosus may also use buffaloes as its intermediate host.

[Study of lesional aspects of hydatid echinococcosis in man in Mauritania: fertility, histology of hydatid cysts and protoscolex viability]

A lesional study on human hydatidosis (localization, fertility of cysts, protoscolex viability, and histological structure) focused on 63 human hydatid cysts from patients operated at CHN of Nouakchott was conducted during the period 1997-2007. The authors report the following results: the annual surgical incidence rate was in the order of 1.2% per 100,000 inhabitants. The lung was the primary localization of cyst (52%) followed by the liver (33%), spleen (4%), brain (3%), heart (2%), breasts (2%), kidney (2%), diaphragm (1%), and peritoneum (1%). The pulmonary cysts were larger and more fertile (76%) with protoscoleces also more viable (70%) compared with liver cysts (67-62%). The histology of hydatid cysts revealed in most cases a histological structure consistent with that described in the literature: thick cuticle, membrane proligeous, and capsules visible.

Sequence analysis of cox1 and nad1 genes in Echinococcus granulosus G3 genotype in camels (Camelus dromedarius) from central Iran

Nineteen hydatid cyst isolates collected from camels in central Iran were subjected to sequences analysis of mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes. A consensus sequence obtained containing 366 nucleotides for cox1 and 471 nucleotides for nad1 genes. Overall, the camel isolates indicated five different sequences in cox1 and nine in nad1 genes. The sequences analysis indicated that 26.3%, 42.1%, and 31.6% of isolates belonging to G1, G3, and G6 genotypes of Echinococcus granulosus, respectively. The isolates with G3 genotype indicated one cox1 sequence having 100% homology with reference G3 sequence (AN: M84663) and two different nad1 sequences, one having 100% homology with reference G3 sequence (AN: AJ237634) and the other with a silent mutation (G to A) in position 279. The presence of G3 genotype (buffalo strain) of E. granulosus as dominant genotype in camels is emphasized. As G3 genotype has formerly been reported in human, the epidemiological role of camels is warranted in future surveys.

Rostellar hook morphology of larval Echinococcus granulosus isolates from the Indian buffalo and Iranian sheep, cattle and camel

Isolates of Echinococcus granulosus from the Indian buffalo and Iranian sheep, cattle and camels were characterized on the basis of rostellar hook morphology of the protoscolices. Results obtained indicated phenotypic polymorphism among parasites isolated from different host species. Isolates from buffalo are morphologically quite different from those of the more common sheep and cattle isolates and may represent a different strain, adapted to buffalo. In the Sari region of northern Iran, two morphologically distinct forms of E. granulosus, one in sheep and one in camels, were identified. Total length and handle length of both large and small hooks were considered the most variable characteristics which could be used not only for differentiating parasite isolates from different host species but also the origin of infection in the definitive host. We therefore suggest that larval hook morphology may be considered as a valid criterion for the identification of E. granulosus strains in Iran.

Echinococcosis/hydatidosis: a severe threat in Mediterranean countries

Echinococcosis/hydatidosis is one of the most important parasitic zoonotic diseases in the world. Both cystic hydatidosis (CE) caused by Echinococcus granulosus and alveolar echinococcosis (AE) caused by E. multilocularis have been reported in several countries of the Mediterranean region (MR). E. granulosus has always been present in the MR and is the most common species. This parasite depends on the dog-sheep cycle and is actively transmitted in all pastoral regions where sheep, cattle and camelids predominate. E. multilocularis occurs only sporadically in limited areas of France, Serbia and Montenegro, Turkey, Tunisia and Morocco. However recent evidence indicates that it is spreading into other regions of the Mediterranean. Due to the lack of well-documented data, and to the fact that CE is not a notifiable disease in the majority of M countries, the precise incidence and prevalence of CE in humans and animals are not known. Published data suggests that prevalence is rather high in North Africa, Turkey, Greece, and in several regions of Italy and Spain. CE is an increasing public health and socio-economic concern due to the considerable morbidity rates that give rise to high economic losses both in the public health sector and in the livestock industry. Hospitalisation for human CE lasts from 2 weeks to more than 1 month in case of surgery. A number of factors contribute to the increase of prevalence and to the spreading of CE in the MR. These include the diversity of livestock production systems (predominantly extensive, traditional animal husbandry), small, ill-equipped and unsupervised slaughter-houses, illegal and family slaughtering, low public awareness of hydatid diseases, and the high population of stray dogs. Cyprus is the only country where an eradication programme has been successfully implemented. There have been, however, important developments in the last decade in CE epidemiology, in the diagnosis of canine infection, in strain characterisation and in immune strategies against CE in animals. This scientific progress, together with effective health education programmes, will likely improve control programmes and reduce the time required to achieve significant decreases in prevalence or eradication.

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

Hydatid cysts were recovered from 35.2% (233/661) of camels (Camelus dromedarius) slaughtered in five different regions of Iran. The degree of prevalence between males (34.4%) and females (36.6%) was not statistically significant. The highest rate of infection (59.3%) was found in the Isfahan region (in the central part of Iran) while the lowest (25.7%) was found in Kerman province. The organ distribution of cysts was 49.4% in lungs alone, 30.0% in both liver and lungs, 14.6% in liver only and 6.0% in other organs. Therefore, the lungs were the predominant sites of the hydatid cyst. The range in the number of cysts was 1–48 in infected animals. The majority of the camels had 1–5 cysts, with 21.9%, 11.6% and 5.6% of infected camels having 6–10, 11–20 and 21 or more cysts respectively. There was a direct relationship between the rate and intensity of infection and host age. The fertility rate of lung cysts (69.7%) was higher than that of liver cysts (58.7%) and other organs (50.0%) whilst the viability rate of protoscoleces of liver fertile cysts (80.3%) was significantly higher than that of lung cysts (55.8%) and other organs (57.1%). The role of camels in the epidemiology of Echinococcus granulosus in Iran is discussed.

Intraspecific variation of Echinococcus granulosus in livestock from Peru

Echinococcus granulosus infection is a problem of public health in livestock-rearing regions of Latin America, like in Peru. This species is characterized by the morphometry of the large and small rostellar hooks in both metacestodes and adult worms. The aim of this work was to study biometrical characteristics of rostellar hooks in hydatid cysts (lung and liver) from some Peruvian provinces (Arequipa, Cuzco, Huancavelica, Junin and Puno). The biometrical analysis was obtained in a digital system for image analysis. The following parameters were studied: area, perimeter, length and width total of the handle, the blade and the distance between the blade and the guard of large and small hooks. For statistical analysis Student's t-test and Analysis of Variance (ANOVA) with Pos-test of Tukey were used, considering the values of p< or =0.05 as of statistic significance. All morphometric characters of large and small hooks were highly significant (p<0.000), when data were compared among the samples from the different provinces. Rostellar hooks in specimens from Huancavelica presented smallest measurements, whereas hooks in specimens from Junin were bigger in relation to the total and blade measurements. Generally, samples from Arequipa presented the biggest large hooks in relation to the handle parameters. The rostellar hooks of cattle and sheep hosts varied depending on the geographic localization, host and organ. Hooks recovered from the lungs were larger than those collected in the liver. It was concluded that morphometry using computer image analysis allows the characterization of E. granulosus. The rostellar hooks presented morphometric polymorphism.

Taxonomic position and geographical distribution of the common sheep G1 and camel G6 strains of Echinococcus granulosus in three African countries

The taxonomic and phylogenetic status of Echinococcus granulosus strains are still controversial and under discussion. In the present study, we investigated the genetic polymorphism of E. granulosus isolates originating from three countries of Africa, including a region of Algeria, where the common G1 sheep and the camel G6 strains coexist sympatrically. Seventy-one hydatid cysts were collected from sheep, cattle, camels, and humans. Two mitochondrial markers (cox1 and nad1) were used for strain identification. Two nuclear markers (actII and hbx2) were used to study the possible occurrence of cross-fertilization. Despite the heterogeneity observed among the G1 isolates, they were all localized within one robust cluster. A second strong cluster was also observed containing all of the G6 isolates. Both strains appeared as two distinct groups, and no cases of interbreeding were found. Thus, the attribution of a species rank can be suggested. We also found the Tasmanian sheep G2 strain for the first time in Africa. Because of the slight variations observed between the common sheep and the Tasmanian sheep strains, further studies should be carried out to elucidate the epidemiological relevance of this genetic discrimination.

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.

Waterborne zoonotic helminthiases

This review deals with waterborne zoonotic helminths, many of which are opportunistic parasites spreading directly from animals to man or man to animals through water that is either ingested or that contains forms capable of skin penetration. Disease severity ranges from being rapidly fatal to low-grade chronic infections that may be asymptomatic for many years. The most significant zoonotic waterborne helminthic diseases are either snail-mediated, copepod-mediated or transmitted by faecal-contaminated water. Snail-mediated helminthiases described here are caused by digenetic trematodes that undergo complex life cycles involving various species of aquatic snails. These diseases include schistosomiasis, cercarial dermatitis, fascioliasis and fasciolopsiasis. The primary copepod-mediated helminthiases are sparganosis, gnathostomiasis and dracunculiasis, and the major faecal-contaminated water helminthiases are cysticercosis, hydatid disease and larva migrans. Generally, only parasites whose infective stages can be transmitted directly by water are discussed in this article. Although many do not require a water environment in which to complete their life cycle, their infective stages can certainly be distributed and acquired directly through water. Transmission via the external environment is necessary for many helminth parasites, with water and faecal contamination being important considerations. Human behaviour, particularly poor hygiene, is a major factor in the re-emergence, and spread of parasitic infections. Also important in assessing the risk of infection by water transmission are human habits and population density, the prevalence of infection in them and in alternate animal hosts, methods of treating sewage and drinking water, and climate. Disease prevention methods, including disease surveillance, education and improved drinking water treatment are described.

Transmission dynamics of the Echinococcus granulosus sheep-dog strain (G1 genotype) in camels in Tunisia

Cystic echinococcosis, caused by Echinococcus granulosus, is highly endemic in North Africa and the Middle East. This paper examines the abundance and prevalence of infection of E. granulosus in camels in Tunisia. No cysts were found in 103 camels from Kébili, whilst 19 of 188 camels from Benguerden (10.1%) were infected. Of the cysts found 95% were considered fertile with the presence of protoscolices and 80% of protoscolices were considered viable by their ability to exclude aqueous eosin. Molecular techniques were used on cyst material from camels and this demonstrated that the study animals were infected with the G1 sheep strain of E. granulosus. Observed data were fitted to a mathematical model by maximum likelihood techniques to define the parameters and their confidence limits and the negative binomial distribution was used to define the error variance in the observed data. The infection pressure to camels was somewhat lower in comparison to sheep reported in an earlier study. However, because camels are much longer-lived animals, the results of the model fit suggested that older camels have a relatively high prevalence rate, reaching a most likely value of 32% at age 15 years. This could represent an important source of transmission to dogs and hence indirectly to man of this zonotic strain. In common with similar studies on other species, there was no evidence of parasite-induced immunity in camels.

Molecular epidemiology of cystic echinococcosis

Echinococcus granulosus exhibits substantial genetic diversity that has important implications for the design and development of vaccines, diagnostic reagents and drugs effective against this parasite. DNA approaches that have been used for accurate identification of these genetic variants are presented here as is a description of their application in molecular epidemiological surveys of cystic echinococcosis in different geographical settings and host assemblages. The recent publication of the complete sequences of the mitochondrial (mt) genomes of the horse and sheep strains of E. granulosus and of E. multilocularis, and the availability of mt DNA sequences for a number of other E. granulosus genotypes, has provided additional genetic information that can be used for more in depth strain characterization and taxonomic studies of these parasites. This very rich sequence information has provided a solid molecular basis, along with a range of different biological, epidemiological, biochemical and other molecular-genetic criteria, for revising the taxonomy of the genus Echinococcus. This has been a controversial issue for some time. Furthermore, the accumulating genetic data may allow insight to several other unresolved questions such as confirming the occurrence and precise nature of the E. granulosus G9 genotype and its reservoir in Poland, whether it is present elsewhere, why the camel strain (G6 genotype) appears to affect humans in certain geographical areas but not others, more precise delineation of the host and geographic ranges of the genotypes characterised to date, and whether additional genotypes of E. granulosus remain to be identified.

Epidemiology, clinical manifestations and diagnosis of zoonotic cestode infections: an update

This paper reviews the literature on zoonotic cestode infections with specific reference to the years 1999-2003. The sources and prevalence of various zoonotic tapeworm infections caused by adult and larval stages of the genera Taenia, Echinococcus, Diphyllobothrium, Hymenolepis and Dipylidium continue to be an important cause of morbidity and mortality, not only in most underdeveloped countries but also in industrialized countries, particularly in rural areas or among immigrant groups from endemic areas. The review gives a detailed report on recent molecular epidemiological studies on the taxonomy and phylogenetic variations in Echinococcus granulosus, immunological tests and imaging techniques used in epidemiological surveys and clinical investigations of important adult and larval tapeworm infections of animals and humans. Larval stages or metacestodes of Taenia solium, Echinococcus spp. and pseudophyllidean tapeworms (Spirometra syn. Diphyllobothrium spp.) may reside in various tissues of their intermediate hosts, including humans. In particular, Cysticercus cellulosae (T. solium) and the larvae of E. granulosus, and E. multilocularis, which are predominantly located in the liver, lungs and central nervous system forming various types of cysts, lead to a complex of systemic diseases such as cysticercosis, cystic echinococcosis and alveolar echinococcosis, respectively. Relatively rare clinical manifestations are seen in the muscles, subcutaneous tissue, spleen, kidneys, bones and body cavities.