Changing distribution, diversity, and health impact of Echinococcus multilocularis in Europe and North America: Comparison, connections, and opportunities.

Echinococcosis, Ningxia, China

Recently, the incidence and awareness of tick-borne diseases in humans and animals have increased due to several factors, which in association favor the chances of contact among wild animals and their ectoparasites, domestic animals and humans. Wild and domestic carnivores are considered the primary source of tick-borne zoonotic agents to humans. Among emergent tick-borne pathogens, agents belonging to family Anaplasmataceae (Order Rickettsiales) agents stand out due their worldwide distribution and zoonotic potential. In this review we aimed to review the genetic diversity of the tick-transmitted genera Ehrlichia, Anaplasma and “Candidatus Neoehrlichia sp.” in wild carnivores Caniformia (Canidae, Mustelidae and Ursidae) and Feliformia (Felidae, Hyanidae, Procyonidae and Viverridae) worldwide, discussing the implications for human and domestic animal health and wildlife conservation. Red foxes (Vulpes vulpes) have been identified as hosts for Anaplasma spp. (A. phagocytophilum, Anaplasma ovis, A. platys), Ehrlichia canis and “Candidatus Neoehrlichia sp.” (FU98 strain) and may contribute to the maintaenance of A. phagocytophilum in Europe. Raccoons (Procyon lotor) have been reported as hosts for E. canis, A. bovis, “Candidatus Neoehrlichia lotoris” and A. phagocytophilum, and play a role in the maintenance of A. phagocytophilum in the USA. Raccoon dogs (Nyctereutes procyonoides) may play a role as hosts for A. bovis and A. phagocytophilum. New Ehrlichia and/or Anaplasma genotypes circulate in wild canids and felids from South America and Africa. While Ehrlichia sp. closely related to E. canis has been reported in wild felids from Brazil and Japan, Anaplasma sp. closely related to A. phagocytophilum has been detected in wild felids from Brazil and Africa. Red foxes and mustelids (otters) are exposed to E. canis in countries located in the Mediaterranean basin, probably as a consequence of spillover from domestic dogs. Similarly, E. canis occurs in procyonids in North (raccoons in USA, Spain) and South (Nasua nasua in Brazil) Hemispheres, in areas where E. canis is frequent in dogs. While “Candidatus Neoehrlichia lotoris” seems to be a common and specific agent of raccoons in the USA, “Candidatus Neoehrlichia sp.” (FU98 strain) seems to show a broader range of hosts, since it has been detected in red fox, golden jackal (Canis aureus) and badger (Meles meles) in Europe so far. Brown (Ursus arctos) and black (Ursus americanus) bears seem to play a role as hosts for A. phagocytophilum in the North Hemisphere. Anaplasma bovis has been detected in wild Procyonidae, Canidae and Felidae in Asia and Brazil. In order to assess the real identity of the involved agents, future works should benefit from the application of MLST (Multi Locus Sequence Typing), WGS (Whole Genome Sequencing) and NGS (Next Generation Sequencing) technologies aiming at shedding some light on the role of wild carnivores in the epidemiology of Anaplasmataceae agents.

Summary The presence of the most important definitive and intermediate hosts suggests that conditions for the live cycle of E. multilocularis are favorable in Lithuania. While the main rodent hosts have not been investigated systematically in Lithuania, E. multilocularis has already been identified in one of 5 muskrats (Ondatra zibethicus) captured in the Silutė district. The high prevalence of E. multilocularis in red foxes and raccoon dogs as well as a notable increase of AE in humans document that E. multilocularis is of emerging concern in Lithuania. The human AE cases were recorded from many parts of the country suggesting that the whole territory of Lithuania should be considered as an endemic area for E. multilocularis. Considering the long prepatent period of AE in humans we suggest that this zoonosis is present in the area investigated for at least a few decades.

Unexpected diversity of the cestode Echinococcus multilocularis in wildlife in Canada.

Infectious Canine Hepatitis in Free-Ranging Red Foxes (Vulpes vulpes)

Detection and genotyping of Toxoplasma gondii in wild canids in Serbia

To the Editor: Alveolar echinococcosis (AE), a serious zoonosis caused by the tapeworm Echinococcus multilocularis, has been reported in neighboring countries of Lithuania in recent years (1–4), but no published epidemiologic information is available. The red fox (Vulpes vulpes), the main definitive host of E. multilocularis in Europe (1), and important intermediate rodent hosts (e.g. Arvicola terrestris, Microtus arvalis) are present in Lithuania (5), but to date they have not been investigated systematically. The helminth fauna of carnivores in Lithuania had been investigated in a study in 1976, but no record was made for E. multilocularis (6). Notably, E. multilocularis has recently been identified in 1 of 5 muskrats (Ondatra zibethicus) captured in the Silutė district of Lithuania (7). The objectives of our study were to estimate the prevalence of E. multilocularis in definitive hosts and to gather first information concerning AE in humans in Lithuania. From 1997 to July 2006, 80 AE cases have been diagnosed at the reference hospital for AE, the Hospital of Tuberculosis and Infectious Diseases in cooperation with the Santariskių Clinic, Vilnius University. Diagnoses were based on serologic testing using ELISA (Bordier Affinity, Crissier, Switzerland) and Western blot (LDBIO, Lyon, France) or imaging methods (ultrasound scan, computed tomography). In 6.7% of the cases identified by imaging techniques, serum antibodies were not detected by ELISA. Diagnoses in all cases were confirmed by histopathologic examination or typical liver lesion morphologic features. Most of the cases were registered in the past 5 years (10–16 cases/year in 2002–July 2006 compared with 0–4 cases/year in 1997–2001). In 26 (33%) of 80 patients, metacestodes were found in the bilateral liver lobes; in 20 (25%) metacestodes were found in the right lobe. Metacestodes had also spread into extra hepatic tissues and metastasized to the right lung, right kidney, spleen, and genitals in 18 (23%) of the patients. AE was diagnosed in 62 (78%) of patients in the third to fourth clinical stage of the disease, according to the PNM (P, parasitic mass in the liver; N, involvement of neighboring organs; M, metastasis) classification: P2-3N0-1M0, P4N1M1 (8); twelve (15%) patients died, 7 of them within 4–24 months after diagnosis. The patients’ ages varied from 21 to 83 years (mean age 58 years). Women were more frequently infected (63%) than men (38%), which could be explained by women’s more frequent involvement in gardening. Eighty-one percent of AE patients were farmers or persons involved in agricultural activities. Most AE patients originated in the northwestern and northeastern parts of Lithuania, but cases were recorded from many parts of the country (Figure), which suggests that the whole territory of Lithuania should be considered as an AE-endemic area. Figure Number of patients (shown in boldface) diagnosed with human alveolar echinococcosis at the Hospital of Tuberculosis and Infectious Diseases, Vilnius University, from 1997 through July 2006 in districts of Lithuania. No. Echinococcus multilocularis– ... To assess the prevalence of E. multilocularis in definitive hosts, the small intestines of 206 hunted red foxes were collected from randomly selected districts from October 2001 to April 2004 and examined following strict safety precautions by the sedimentation and counting technique. E. multilocularis was detected in 118 red foxes (57.3%, 95% confidence interval [CI] 50.2%–64.1%). The tapeworm was present in foxes from most tested localities; the highest prevalence of 62.3% (CI 49.0–74.4%) was observed in the Kaunas district (Figure). The median worm burden per infected fox was 56 (1–20, 924) in this district. The high prevalences of E. multilocularis in foxes in the examined areas support the hypothesis that foxes play the key role as definitive hosts in the biology of this tapeworm in Lithuania. In the framework of an epidemiologic investigation on E. granulosus, the contents of small necrotic lesions (size 3–8 mm) found in 21 randomly collected pig livers from small family farms in the southwestern part of Lithuania were also investigated by PCR (9); 3 lesions were positive for AE. Further, 2 of 34 dogs from rural areas in the southwestern part of Lithuania shed taeniid eggs in feces that were positive for E. multilocularis on examination with a multiplex PCR (10). The high number of human AE cases and the high prevalence of E. multilocularis in definitive wild hosts document that AE is of emerging concern in Lithuania. However, this study cannot conclusively document a recent extension of the parasite’s range and an increase of the infection pressure. Clearly, the identification of AE in pigs and of E. multilocularis in dogs from small family farms demonstrates that transmission of E. multilocularis occurs in rural environments in close proximity to the population.

Simple SummaryWild carnivores can harbor a dangerous tapeworm Echinococcus sp. that causes an important food-borne disease called echinococcosis. This study uses molecular methods to assess the prevalence of the tapeworm Echinococcus multilocularis, E. canadensis, and E. granulosus sensu stricto in the stool of red foxes, wolves, golden jackals, martens, lynxes, badgers, and otter. Red foxes (29.1%) and golden jackals (18%) were positive for E. multilocularis (EM), while all other animals were negative for all Echinococcus species tested in this study. Statistical analysis showed that the prevalence of EM is associated only with the region where the sample originated and not by species, age, or sex of the animal. Central and south regions of Slovenia have a higher EM prevalence and risk of infection. Due to habitat expansion and an increasing population, golden jackal may soon become an important source for human infection with EM.Wild carnivores are definitive hosts and potential reservoirs for the tapeworm Echinococcus sp. which can cause cystic and alveolar echinococcosis. Both are considered neglected and important food-borne pandemics. This study is the first to molecularly test Slovenian wild carnivores for Echinococcus species that can cause disease in humans. Fecal samples from 210 red foxes (Vulpes vulpes), 42 wolves (Canis lupus), 39 golden jackals (Canis aureus), 18 martens (Marten sp.), 2 Eurasian lynx (Lynx lynx), 2 European badger (Meles meles), and 1 Eurasian otter (Lutra lutra) were examined for Echinococcus granulosus sensu lato (EGsl: E. granulosus sensu stricto, E. canadensis) and E. multilocularis (EM) using real-time PCR. Red foxes (29.1%) and golden jackals (18%) were positive for EM. All animals examined were negative for EGsl. Univariate analysis showed no significant differences in EM prevalence with respect to animal species (red fox vs., golden jackal) (p = 0.22), age (p = 0.12), and sex (p = 0.18). Prevalence of EM was associated with the region (p < 0.001), with regions in central and southern Slovenia having higher EM prevalence and risk of infection. Due to the increase in population and expansion of habitat, the golden jackal may soon become as important definitive host for EM as the red fox.

Detection of European Strain of<i>Echinococcus multilocularis</i>in North America

Anthropogenic activities facilitate temporal overlaps and spatial partitions among sympatric canids in a human-modified landscape of Bulgaria

Alveolar Echinococcosis in Humans: The Current Situation in Central Europe and the Need for Countermeasures

The circadian activity of selected mammal species and the temporal overlap with human presence or between species were analysed in 2013–2014 on the territory of the Sinite Kamani Nature Park, Eastern Stara Planina. The purpose of this study was to determine how the human presence affected the circadian activity of mammal species in this protected area. The wild boar (n = 68) showed 22% overlap with the humans (n = 54) in its circadian activity (Δ = 0.22, CI 0.02–0.21) while the roe deer (n = 144) activity overlapped in 49% with the human activity (Δ = 0.49, CI 0.29–0.51). The European brown hare (n=26) activity had a 23% overlap (Δ = 0.23, CI 0.07–0.26), the golden jackal (n = 42) – 36% (Δ = 0.36, CI 0.22–0.49) and the red fox (n = 131) – 24% (Δ = 0.24, CI 0.06–0.25). The overlap between the red fox and European brown hare activity was 81% (Δ = 0.81, CI 0.71–0.93), between red fox and golden jackal – 71% (Δ = 0.71, CI0.49–0.77) and between red fox and Martes sp. – 81% (Δ = 0.81, CI 0.72–0.93). The target species avoided the range of time when humans were active. This forced the species to use a narrower temporal niche when sharing the same space. These results provided insights for the better management of the species in the protected areas.

Using citizen science to inform urban canid management

Human cystic echinococcosis (CE) is known to be endemic in the Tibet Autonomous Region (TAR), China; however, there is relatively little data from hospital records or community prevalence studies, and the situation regarding occurrence of human alveolar echinococcosis (AE) is unclear. Here we review the available reports about human echinococcosis in the seven prefectures of TAR. In addition, two pilot studies by mass screening using ultrasound (with serology) were undertaken (2006/7) in Dangxiong County of Lhasa Prefecture (north central TAR) and Dingqing County of Changdu Prefecture (eastern TAR). In Dangxiong County a prevalence of 9.9% (55/557) for human CE was obtained but no human AE cases were detected. By contrast, in Dingqing County (N= 232 persons screened), 11 CE cases (4.7%) and 12 AE cases (5.2%) (including one mixed CE and AE case) were diagnosed by ultrasound. Hospital records and published reports indicated that CE cases were recorded in all of seven prefectures in Tibet Autonomous Region, and AE cases in four prefectures. Incidence rates of human CE were estimated to range from 1.9 to 155 per 100,000 across the seven prefectures of TAR, with a regional incidence of 45.1 per 100,000. Incidence of AE was estimated to be between 0.6 and 2.8 cases per 100,000. Overall for TAR, human AE prevalence appeared relatively low; however, the pilot mass screening in Dingqing in eastern TAR indicated that human AE disease is a potential public health problem, possibly similar to that already well described in Tibetan communities bordering TAR in north-west Sichuan and south-west Qinghai provinces.

Echinococcus spp. are cestode parasites commonly known as small tapeworms of carnivorous animals. Their medical importance lies in the infection of humans by the larval stage of the parasites, predominantly including Echinococcus granulosus, which is the causative agent of cystic echinococcosis (CE) and Echinococcus multilocularis, which causes alveolar echinococcosis (AE). A few other species or genotypes are only very rarely or not at all found in humans. Due to the emerging situation in many parts of Europe, the present article will predominantly focus on E. multilocularis . The natural life cycle of E. multilocularis involves predominantly red and arctic foxes as definitive hosts, but domestic dogs can also become infected and represent an important infection source for humans in highly endemic areas. In the definitive host, egg production starts as early as 28 days after infection. After egg ingestion by a rodent or a human, larval maturation will occur practically exclusively within the liver tissue. The geographic distribution of E. multilocularis is restricted to the northern hemisphere. In Europe, relatively frequent reports of AE in humans occur in central and eastern France, Switzerland, Austria and Germany. Within the past ten years, the endemic area of Europe now includes many more countries such as Belgium, The Netherlands, Italy, and most former Eastern countries as far as up to Estonia. The Asian areas where E. multilocularis occurs include the whole zone from the White Sea eastward to the Bering Strait, covering large parts of Siberia, western and central parts of China and northern Japan. Worldwide there are scant data on the overall prevalence of human AE. Some well-documented studies demonstrate a generally low prevalence among affected human populations. The annual mean incidence of new cases in different areas including Switzerland, France, Germany and Japan has therefore been reported to vary between 0.1 and 1.2/ 100,000 inhabitants. The incidence of human cases correlates with the prevalence in foxes and the fox population density. Recently, a study documented that a fourfold increase of the fox population in Switzerland resulted in a statistically significant increase of the annual incidence of AE cases [1] (Schweiger et al., 2007). This dramatic increase in red fox populations has also been reported throughout Europe, especially in urban areas. The so-called city-fox phenomenon and, thereafter, the increased proximity of foxes with humans and an urban domestic dog – rodent cycle may, therefore, have significant public health implications [1-3]. In infected humans the E. multilocularis metacestode (larva) develops primarily in the liver. Occasionally, secondary lesions form metastases in the lungs, brain and other organs. The typical lesion appears macroscopically as a dispersed mass of fibrous tissue with a conglomerate of scattered vesiculated cavities with diameters ranging from a few millimeters to centimeters in size. In advanced chronic cases, a central necrotic cavity containing a viscous fluid may form, and rarely there is a bacterial superinfection. The lesion often contains focal zones of calcification, typically within the metacestode tissue. Histologically, the hepatic lesion is characterized by a conglomerate of small vesicles and cysts demarcated by a thin PAS-positive laminated layer with or without an inner germinative layer [4]. Parasite proliferation is usually accompanied by a granulomatous host reaction, including vigorous synthesis of fibrous and germinative tissue in the periphery of the metacestode, but also necrotic changes centrally. In contrast to lesions in susceptible rodent hosts, lesions from infected human patients rarely show protoscolex formation within Correspondence: bruno.gottstein@ipa.unibe.ch Faculty of Medicine, Institute of Parasitology, University of Bern, Bern, Switzerland Gottstein Acta Veterinaria Scandinavica 2010, 52(Suppl 1):S5 http://www.actavetscand.com/content/52/S1/S5