Monitoring of environmental contamination by Echinococcus multilocularis in an urban fringe forest park in Hokkaido, Japan

Molecular phylodiagnosis of Echinococcus multilocularis and Echinococcus granulosus among canids in Guilan province, northern Iran

Canine-transmitted worms and an uncontrolled deworming program of stray dogs have caused that accurate diagnosis of zoonotic parasites received notable attention in endemic regions. This study aimed to assess the presence of E. multilocularis and E. granulosus infections in canids from Guilan province, northern Iran. A total of 272 fecal samples from carnivores were collected across 24 different regions in Guilan province between 2023 and 2024. All fecal specimens were observed following concentration and flotation techniques. DNAs of taeniid eggs were extracted, amplified, and sequenced targeting of specific mitochondrial Cox1 gene for E. granulosus and NAD 1 gene for E. multilocularis. On the base of molecular and phylogenetic analysis 1.47 % (in jackal) and 25 % (in dogs and jackal) of samples were positive for E. multilocularis and E. granulosus sensu strico G1 genotype, respectively. Molecular technique was found to be more sensitive in detecting infection in comparison with conventional techniques. Sequence analysis of Cox1 indicated a high genetic diversity (Haplotype diversity; 0.933; Number of haplotypes, h: 7) in E. granulosus G1. Current findings show that canids particularly jackals play potential role of definitive host in maintenance and transmission dynamic of E. multilocularis and E. granulosus in northern Iran. The presence of these infections is of particular concern in Guilan province due to the high influx of tourists, increasing the risk of transmission to humans. Therefore, the implementation of preventive programs is warranted to apply hygienic practices and adjusting deworming programs for the canids and at-risk individuals in the region.

Virological, pathological, and glycovirological investigations of an Ezo red fox and a tanuki naturally infected with H5N1 high pathogenicity avian influenza viruses in Hokkaido, Japan

In winter/spring 2021-2022, high pathogenicity avian influenza viruses (HPAIVs) that are genetically closely related to each other were detected worldwide. In a public garden in Sapporo, Hokkaido, Japan, a crow die-off by HPAIV infection occurred from March 29 to May 18, 2022. During the event, H5N1 HPAIVs were isolated from an Ezo red fox (Vulpes vulpes schrencki) and a tanuki (Nyctereutes procyonoides albus) found in the same garden. The fox showed viral meningoencephalitis and moderate virus replication in the upper respiratory tract, whereas the tanuki showed viral conjunctivitis and secondary bacterial infection in the eyes accompanied with visceral larva migrans. Viruses isolated from the fox and the tanuki were genetically closely related to those isolated from crows in the same garden. Various α2-3 sialosides were found in the respiratory tracts of these canid mammals, consistent with HPAIV infections in these animals. This study highlighted the importance of monitoring HPAIV infections in wild carnivore mammals to detect the potential virus spreading in nature.

Sensitivity comparison between Mini-FLOTAC and conventional techniques for the detection of Echinococcus multilocularis eggs

Canines serve as the definitive host of Echinococcus multilocularis. This study evaluated the sensitivity of the Mini-FLOTAC technique (MF) for the detection of E. multilocularis eggs in definitive hosts. First, we investigated the effects of heat inactivation and preservative conditions on the detection rate of eggs obtained from experimentally infected dogs. The sensitivity of MF was compared with that of eight other techniques: the centrifugal flotation with sucrose or zinc sulfate, MGL, AMS III, and a combination of MF and flotation/sedimentation techniques. Finally, we compared the sensitivity of MF and the centrifugal flotation with sucrose for the feces of E. multilocularis-infected foxes. The detection rate reached a plateau level with a specific gravity (s.g.) 1.22 for fresh eggs, but the highest rates were obtained with s.g. greater than 1.32 for heat-inactivated eggs. There was no significant difference in the detection rate among the preservative conditions. MF showed significantly higher EPG than the other techniques. Moreover, it showed higher diagnostic sensitivity for the fox feces than the centrifugal flotation technique. These results suggest that heat inactivation may alter s.g. of E. multilocularis eggs and that MF with zinc sulfate (s.g. = 1.32) would be effective for detecting heat-inactivated E. multilocularis eggs.

Molecular genotyping of Giardia duodenalis in children from Behbahan, southwestern Iran

Giardia duodenalis is an intestinal flagellated protozoan that infects humans and several animal species. Giardiasis causing more than 200 million symptomatic infections globally is one of the most common causes of diarrhea in developing countries. Based on molecular studies mainly targeting the small-subunit (SSU) rRNA gene locus of the parasite, eight assemblages (A to H) have been identified in humans and other animal species. The aim of the current study was to evaluate the frequency and molecular diversity of G. duodenalis in children from rural and urban day care centers from Behbahan, southwestern Iran. This cross-sectional study was based on a concentration method for the microscopic detection of G. duodenalis in stool samples of 450 children, aged 1-7 years, in Behbahan, southwestern Iran. The survey was conducted from December 2015 to May 2016. PCR methods targeting the SSU rRNA and triose phosphate isomerase (TPI) genes of G. duodenalis were used for the identification and genotyping of the parasite isolates. Based on sucrose flotation and microscopy techniques, 2.7% (12/450) of children were infected with G. duodenalis, of which six (50.0%) were males and the other six (50.0%) were females. Overall, 91.7% (11/12) of the infections were detected in children from rural areas. The SSU rRNA and TPI genes were amplified successfully in nine and eight, respectively, of the Giardia-positive samples at microscopy. Among the eight TPI sequences, assemblage A, sub-assemblage AII, was identified in five of the isolates. The sequences of the three remaining samples were untypable. Although no significantly statistical difference between genotype and clinical symptoms was found, five out of the eight isolates identified as assemblage A were obtained in asymptomatic children. Giardia duodenalis infections were more prevalent in children from rural day care schools, and the predominant assemblage was A, sub-assemblage AII. The higher prevalence of giardiasis in rural areas might be related to differences in personal hygiene habits, parents' education level, source of drinking water, and inadequate hygienic toilet facilities in rural areas.

The echinococcoses in Asia: The present situation

Human alveolar and cystic echinococcosis, caused by the accidental ingestion of eggs of the tapeworms Echinococcus multilocularis and Echinococcus granulosus sensu lato, respectively, are endemic in Asia. Various Echinococcus species are maintained in domesticated and/or wild mammals through predator-prey interactions. Molecular analysis is used to help differentiate infecting parasite species and genotypes, with the goal of better understanding parasite life cycles in order to aid in the planning and implementation of control programs. This paper discusses the various echinococcoses in Asia, with limited reference to neighboring areas, including parts of Central Asia, Russia, Europe and North America.

Natural larval Echinococcus multilocularis infection in a Norway rat, Rattus norvegicus, captured indoors in Hokkaido, Japan

Natural infection with larval Echinococcus multilocularis was recognized in one of eight Norway rats, Rattus norvegicus, caught indoors in 2009 in Ebetsu, Hokkaido, northern Japan. Cystic lesions were found in the right median and lateral lobes of the liver, with numerous alveolar cysts in the periphery of the lesions. Protoscolices were formed within large cysts. The laminated layers of the cysts were positive for PAS staining. Nested PCR using the primers specific for Taenia mitochondrial 12S rDNA yielded a 250-bp product, and the sequence of the PCR product matched that of E. multilocularis isolates from Hokkaido and Germany. This is the third natural alveolar hydatidosis in R. norvegicus in Japan.

Wilderness in the 'city' revisited: different urbes shape transmission of Echinococcus multilocularis by altering predator and prey communities

The urbanization of Echinococcus multilocularis, the agent of alveolar echinococcosis (AE), is a public health concern worldwide. Here we propose to consider 'urban' habitats under a broad ecological perspective and discuss the effects of human settlements (urbes) on host communities and the process of parasite urbanization. We argue that interactions between landscape features (i.e., landscape composition and configuration) and host communities can shape the heterogeneity of transmission gradients observed within and across different types of human settlement. Due to unique ecological characteristics and public health management priorities, we envisage urban landscapes as a model system to further increase our understanding of host-parasite interactions shaping the circulation of E. multilocularis.

Echinococcosis in wild carnivorous species: epidemiology, genotypic diversity, and implications for veterinary public health

Echinococcosis is a zoonosis caused by helminths of the genus Echinococcus. The infection, one of the 17 neglected tropical diseases listed by the World Health Organization, has a cosmopolitan distribution and can be transmitted through a variety of domestic, synanthropic, and sylvatic cycles. Wildlife has been increasingly regarded as a relevant source of infection to humans, as demonstrated by the fact that a significant proportion of human emerging infectious diseases have a wildlife origin. Based on available epidemiological and molecular evidence, of the nine Echinococcus species currently recognized as valid taxa, E. canadensis G8-G10, E. felidis, E. multilocularis, E. oligarthrus, E. shiquicus, and E. vogeli are primarily transmitted in the wild. E. canadensis G6-G7, E. equinus, E. granulosus s.s., and E. ortleppi are considered to be transmitted mainly through domestic cycles. We summarize here current knowledge on the global epidemiology, geographical distribution and genotype frequency of Echinococcus spp. in wild carnivorous species. Topics addressed include the significance of the wildlife/livestock/human interface, the sympatric occurrence of different Echinococcus species in a given epidemiological scenario, and the role of wildlife as natural reservoir of disease to human and domestic animal populations. We have also discussed the impact that human activity and intervention may cause in the transmission dynamics of echinococcosis, including the human population expansion an encroachment on shrinking natural habitats, the increasing urbanization of wildlife carnivorous species and the related establishment of synanthropic cycles of Echinococcus spp., the land use (e.g. deforestation and agricultural practices), and the unsupervised international trade and translocation of wildlife animals. Following the 'One Health' approach, we have also emphasized that successful veterinary public health interventions in the field of echinococcosis requires an holistic approach to integrate current knowledge on human medicine, veterinary medicine and environmental sciences.

Environmental changes impacting Echinococcus transmission: research to support predictive surveillance and control

Echinococcosis, resulting from infection with tapeworms Echinococcus granulosus and E. multilocularis, has a global distribution with 2-3 million people affected and 200,000 new cases diagnosed annually. Costs of treatment for humans and economic losses to the livestock industry have been estimated to exceed $2 billion. These figures are likely to be an underestimation given the challenges with its early detection and the lack of mandatory official reporting policies in most countries. Despite this global burden, echinococcosis remains a neglected zoonosis. The importance of environmental factors in influencing the transmission intensity and distribution of Echinococcus spp. is increasingly being recognized. With the advent of climate change and the influence of global population expansion, food insecurity and land-use changes, questions about the potential impact of changing temperature, rainfall patterns, increasing urbanization, deforestation, grassland degradation and overgrazing on zoonotic disease transmission are being raised. This study is the first to comprehensively review how climate change and anthropogenic environmental factors contribute to the transmission of echinococcosis mediated by changes in animal population dynamics, spatial overlap of competent hosts and the creation of improved conditions for egg survival. We advocate rigorous scientific research to establish the causal link between specific environmental variables and echinococcosis in humans and the incorporation of environmental, animal and human data collection within a sentinel site surveillance network that will complement satellite remote-sensing information. Identifying the environmental determinants of transmission risk to humans will be vital for the design of more accurate predictive models to guide cost-effective pre-emptive public health action against echinococcosis.

Detection of Echinococcus multilocularis in carnivores in Razavi Khorasan province, Iran using mitochondrial DNA

Background

Echinococcus multilocularis is the source of alveolar echinococcosis, a potentially fatal zoonotic disease. This investigation assessed the presence of E. multilocularis infection in definitive hosts in the Chenaran region of Razavi Khorasan Province, northeastern Iran.

Methodology/Principal Findings

Fecal samples from 77 domestic and stray dogs and 14 wild carnivores were examined using the flotation/sieving method followed by multiplex PCR of mitochondrial genes. The intestinal scraping technique (IST) and the sedimentation and counting technique (SCT) revealed adult Echinococcus in the intestines of five of 10 jackals and of the single wolf examined. Three jackals were infected only with E. multilocularis but two, and the wolf, were infected with both E. multilocularis and E. granulosus. Multiplex PCR revealed E. multilocularis, E. granulosus, and Taenia spp. in 19, 24, and 28 fecal samples, respectively. Echinococcus multilocularis infection was detected in the feces of all wild carnivores sampled including nine jackals, three foxes, one wolf, one hyena, and five dogs (6.5%). Echinococcus granulosus was found in the fecal samples of 16.9% of dogs, 66.7% of jackals, and all of the foxes, the wolf, and the hyena. The feces of 16 (21.8%) dogs, 7 of 9 (77.8%) jackals, and all three foxes, one wolf and one hyena were infected with Taenia spp.

Conclusions/Significance

The prevalence of E. multilocularis in wild carnivores of rural areas of the Chenaran region is high, indicating that the life cycle is being maintained in northeastern Iran with the red fox, jackal, wolf, hyena, and dog as definitive hosts.

Echinococcus multilocularis causes alveolar echinococcosis, a serious zoonotic disease present in many areas of the world. The parasite is maintained in nature through a life cycle in which adult worms in the intestine of carnivores transmit infection to small mammals, predominantly rodents, via eggs in the feces. Humans may accidentally ingest eggs of E. multilocularis through contact with the definitive host or by direct ingestion of contaminated water or foods, causing development of a multivesicular cyst in the viscera, especially liver and lung. We found adult E. multilocularis in the intestine and/or eggs in feces of all wild carnivores examined and in some stray and domestic dogs in villages of Chenaran region, northeastern Iran. The life cycle of E. multilocularis is being maintained in this area by wild carnivores, and the local population and visitors are at risk of infection with alveolar echinococcosis. Intensive health initiatives for control of the parasite and diagnosis of this potentially fatal disease in humans, in this area of Iran, are needed.

Fox defecation behaviour in relation to spatial distribution of voles in an urbanised area: An increasing risk of transmission of Echinococcus multilocularis?

Urbanisation of alveolar echinococcosis is a new phenomenon that has been highlighted during the last few decades. It has thus become necessary to understand the dynamics of transmission of Echinococcus multilocularis in urbanised areas. Spatial heterogeneity of infection by E. multilocularis has been explained as the result of a multifactorial dependence of the transmission in which the factors depend on the scale of the investigation. The aim of this study was to assess, in an urbanised area, the effect of such environmental factors as season, habitat type and the level of urbanisation, on the availability of two major intermediate hosts (Microtus spp. and Arvicola terrestris), the distribution of red fox faeces and the distribution of E. multilocularis as determined by detection of coproantigens in faeces. Results of the study revealed higher densities of Microtus spp. in rural than in peri-urban areas. Moreover this species was highly aggregated in urban wasteland. Arvicola terrestris densities did not appear to be linked to the level of urbanisation or to the type of habitat studied. Distribution of faeces was positively linked to distance walked and to Microtus spp. and A. terrestris distributions whatever the level of urbanisation. Such a distribution pattern could enhance the transmission cycle in urban areas. The Copro-ELISA test results on faeces collected in the field revealed that ODs were significantly negatively correlated with the abundance of A. terrestris. The larger population densities of Microtus spp. found in urban wastelands and the well known predominance of Microtus spp. in the red fox diet in the region suggest that Microtus spp. may play a key role in urban transmission of the parasite in the study area.