Cystic Echinococcosis in Wild Boars (Sus scrofa) and Slaughtered Domestic Ruminants in Algeria

Epidemiological update of cystic echinococcosis in livestock and assessment of practices related to its control in the Mediterranean area

Cystic echinococcosis (CE), caused by the tapeworm Echinococcus granulosus, is a zoonotic parasitic disease that still represents a serious threat to human and animal health worldwide. The Mediterranean basin is recognized as one of the major hotspots of CE due to several factors, including the presence of diverse intermediate host species as well as socio-economic and cultural conditions of local communities. This study aims to take a closer look at epidemiological data on CE in the Mediterranean area and assess the knowledge attitudes and practices of shepherds towards this disease in four countries (Algeria, Greece, Italy and Tunisia), highly endemic for CE, with the final goal of identifying highly endemic risk areas and practices in use which might potentially allow the persistence of E. granulosus infection in these areas. To update the epidemiological scenario of CE in Mediterranean areas, a comprehensive review of peer-reviewed literature on CE prevalence data published during the 2017-2023 period was carried out and, through a geographical information system (GIS), a map displaying the current CE distribution in the Mediterranean area was generated. In addition, a questionnaire survey was conducted through in-depth interviews of the farmers to collect information on their management system as well as knowledge attitudes and practices towards CE. From the farmer-participatory survey some risky practices emerged including the non-regular deworming of dogs or the use of ineffective drugs or dosing, as well as the provision of uncooked animal viscera to dogs. Finally, lower levels of knowledge and awareness of the disease was observed among farmers from North Africa compared with those of European countries. In conclusion, the results obtained highlight that CE is still a very serious problem in Mediterranean areas and increased efforts are needed to promote awareness among farmers and to turn research results into policy in order to reduce the spread of this disease, according to the One Health perspective.

Baiting not-owned dogs against Echinococcus granulosus: innovative tools for integrated control

Cystic echinococcosis (CE), caused by the larval stage of the cestode Echinococcus granulosus, is one of the most widespread zoonoses in Mediterranean countries. Baiting not-owned dogs with praziquantel (PZQ), due to their key role in the maintaining the transmission of CE, currently appears to be the most effective way to limit the transmission of CE, as well as an important aspect to introduce for the control of this parasitic disease. Therefore, this study aims to test 3 types of PZQ-based baits by evaluating different parameters (integrity over time, attractiveness and palatability for dogs, and mechanical resistance after release to different altitudes) and the bait acceptance in field by target animals, i.e. not-owned dogs, by using camera traps. The double PZQ-laced baits (with a double layer of highly palatable chews) showed the greatest resistance in the environment while also preserving the attractiveness and palatability up to 10 days, also withstood heights of 25 m, thus resulting as the most suitable also for drone delivery. The results on the field showed that most of the baits were consumed by not-owned dogs (82.2%), while the remaining were consumed by wild boars (8.9%), foxes (6.7%), badgers (1.1%) and hedgehogs (1.1%), confirming the specific and high attractiveness of the double PZQ-laced baits for the target population and highlights how an anthelmintic baiting programme may be a viable tool for the management of E. granulosus among free-ranging dog populations in endemic rural areas.

Attitude and awareness of Algerian university students about cystic echinococcosis: A cross-sectional study

Cystic echinococcosis is a neglected tropical parasitic disease affecting both humans and animals with considerable socioeconomic impact on affected pastoral and poor communities. CE is endemic in the Mediterranean basin, including Algeria posing a real threat for either animal and public health. This study was conducted to evaluate the level of awareness and knowledge of Algerian university students about this disease and to describe their attitude toward some risky practices. Results showed that despite that a high number of students (76.1%) have heard about CE, their level of knowledge is however medium (63.3%) especially among students of non medical and life sciences specialties. The gaps of knowledge concerns especially the life cycle of the parasite even they are aware about the association of dogs (43.7%) and sheep (59.4%) and considered that dogs are the main source of contamination of humans (58.1%) through contaminated foods (45%) or direct contact with their faeces (44.5%). Regarding their practice, a good level was shown since washing vegetables (99.2%) and washing hands after touching a dog (97.9%) and dogs deworming (82%) were common. These results highlight the need to improve knowledge about the transmission cycle of the parasite through awareness campaign targeting students which could be helpful in CE eradication.

Frequency and genetic diversity of Echinococcus granulosus sensu stricto in sheep and cattle from the steppe region of Djelfa, Algeria

Cystic echinococcosis (CE) of humans and animals is caused by various species of Echinococcus granulosus sensu lato. Of these, E. granulosus sensu stricto has the widest geographical distribution and is the most important agent of human cystic echinococcosis. Previous molecular studies showed that E. granulosus s.s. isolates from the Middle East and western Asia exhibit higher intraspecific diversity than those from other parts of the world, which led to hypotheses on the origin of the species in that region. However, various high-endemicity regions have not been sufficiently covered by such studies, including northern Africa as a well-known focus of this parasite. Here, we report data on the mitochondrial cox1 gene (1609bp) sequence diversity of E. granulosus s.s. from Algerian livestock. An abattoir survey of 1278 animals from the Algerian steppe region (Djelfa) resulted in CE prevalence of 13.9% in cattle (n = 266), 5.7% in sheep (n = 975), and 0% in goats (n = 37). All of 125 molecularly examined cyst isolates belonged to E. granulosus s.s. In total, 73 haplotypes were found, only five of which have been previously reported (from the Middle East and Australia). One haplotype sequence (EgAlg01X) was found to contain an insertion of three bases at the end of the gene. To the best of our knowledge, this has not been reported before for Echinococcus spp. Diversity values of our panel of Algerian samples were in the range of those that have been previously reported from the Middle East and far higher than those from elsewhere. This, together with the low number of shared haplotypes, indicates a more complex biogeographical history of this parasite than hitherto assumed.

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.

Molecular characterization of Echinococcus granulosus sensu stricto and Echinococcus canadensis in humans and livestock from Algeria

In Algeria, previous studies investigated genotypes of Echinococcus granulosus sensu lato in animals and identified E. granulosus sensu stricto (s.s.) genotypes G1 and G3 whereas Echinococcus canadensis genotype G6 was only reported from dromedary cysts. Molecular data on human cystic echinococcosis (CE) were limited. We implemented a large genotyping study of hydatid cysts from humans and livestock animals to specify CE's molecular epidemiology and the genetic diversity in Algeria. Fifty-four human CE cysts from patients predominantly admitted in surgical units from Mustapha Hospital, Algiers, and 16 cysts from livestock animals gathered in two geographically distinct slaughterhouses, Tiaret and Tamanrasset, were collected. Molecular characterization was performed using sequencing of two mitochondrial genes, cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit I (NDI). In humans, G1 of E. granulosus s.s. was the main genotype (90.7 %); four samples (7.4 %) were characterized as E. granulosus s.s. G3 and one cyst as E. canadensis G6 (1.8 %). This molecular confirmation of E. canadensis G6 human infection in Algeria was observed in a Tuareg female living in a desertic area in Tamanrasset. All cysts from sheep, cattle, and goat were identified as E. granulosus s.s. G1 and the two cysts originating from dromedary as E. canadensis G6. Twenty concatenated haplotypes (COI + NDI) were characterized. Among E. granulosus s.s., one haplotype (HL1) was highly predominant in both humans and animals cysts (71.6 %). This study revealed main occurrence of E. granulosus s.s. in humans and livestock animals, with description of a predominant shared haplotype corresponding to the main worldwide observed haplotype E.granulosus s.s. G1. E. canadensis G6 was limited to South Algeria, in dromedary as well as in human.