Main Definitive Host Research Articles

An innovative strategy for deworming dogs in Mediterranean areas highly endemic for cystic echinococcosis

BackgroundCystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus sensu lato, is a zoonotic parasitic disease of economic and public health importance worldwide, especially in the Mediterranean area. Canids are the main definitive hosts of the adult cestode contaminating the environment with parasite eggs released with feces. In rural and peri-urban areas, the risk of transmission to livestock as well as humans is high because of the free-roaming behavior of owned/not owned dogs. Collecting data on animal movements and behavior using GPS dataloggers could be a milestone to contain the spread of this parasitosis. Thus, this study aims to develop a comprehensive control strategy, focused on deworming a dog population in a pilot area of southern Italy (Campania region) highly endemic for CE.MethodsAccordingly, five sheep farms, tested to be positive for CE, were selected. In each sheep farm, all shepherd dogs present were treated every 2 months with praziquantel. Furthermore, 15 GPS dataloggers were applied to sheep and dogs, and their movements were tracked for 1 month; the distances that they traveled and their respective home ranges were determined using minimum convex polygon (MCP) analysis with a convex hull geometry as output.ResultsThe results showed that the mean daily walking distances traveled by sheep and dogs did not significantly differ. Over 90% of the point locations collected by GPS fell within 1500 mt of the farm, and the longest distances were traveled between 10:00 and 17:00. In all the sheep farms monitored, the area traversed by the animals during their daily activities showed an extension of < 250 hectares. Based on the home range of the animals, the area with the highest risk of access from canids (minimum safe convex polygon) was estimated around the centroid of each farm, and a potential scheme for the delivery of praziquantel-laced baits for the treatment of not owned dogs gravitating around the grazing area was designed.ConclusionsThis study documents the usefulness of geospatial technology in supporting parasite control strategies to reduce disease transmission.Graphical

Intermediate and definitive hosts of wild Schistosoma mansoni: ecological niche modeling of hosts in low endemicity areas.

The relationship between the environment and animal life began to be seen as an important tool to help control zoonoses. Climate variations lead to changes in the environment, which can influence the spatial distribution of species and, consequently, the spread of diseases to humans. Considered the main non-human definitive host species of Schistosoma mansoni in Brazil, the wild rodent Nectomys squamipes plays an important role as a reservoir in maintaining the schistosomiasis cycle in the absence of humans. This study demonstrates the results of ecological niche modeling of intermediate and definitive wild hosts of S. mansoni in the Regional Health Superintendence of Barbacena (Minas Gerais State), which has registered 31 municipalities, 80% of which are classified as endemic for parasitosis. Environmental variables associated with the distribution of each species were used based on information from the scientific collections of Global Biodiversity Information Facility (GBIF) and Species Link to project the ecological niche model in the geographic space. Abiotic variables such as the mean annual temperature, isothermality, and precipitation seasonality were obtained from World Clim. Ecological niche modeling of the wild host, N. squamipes, revealed the occurrence of the species in geographic overlap with the Biomphalaria species. Knowing the influence of bioclimatic variables and identifying favorable conditions for the establishment, occurrence, and distribution of species are important information for developing strategic actions for the surveillance and control of this endemic species. The presence of the definitive wild host needs to be considered by control programs of schistosomiasis.

Centrorhynchus spp. (Acanthocephala) in South America: new anuran record and checklist of vertebrate hosts.

The aim of this study was to record Centrorhynchus sp. associated with the exotic species Aquarana catesbeiana (bullfrog) in southern Brazil and to present a checklist of vertebrate hosts in South America. Twenty-nine adults and juveniles of A. catesbeiana were collected in Capão do Leão, state of Rio Grande do Sul, Brazil, between October 2019 and December 2020. We found 275 specimens of Centrorhynchus sp. cystacanths in the stomach musculature and coelomic cavity of 55.1% of hosts (16). There was no significant differences in the prevalence and mean intensity of infection with cystacanths when compared males and females of A. catesbeiana. The prevalence was significantly higher in adults than in juveniles. The checklist presents 106 species of vertebrate hosts and 14 taxa of Centrorhynchus recorded in nine South American countries. Avian were the main definitive hosts of Centrorhynchus spp. and snakes Dipsadidae, anurans Hylidae and Leptodactylidae the main paratenic hosts in South America. This is the first record of Centrorhynchus cystacanths in A. catesbeiana in the South America. The study provides tools to help understand the parasitic relationships between species of Centrorhynchus and A. catesbeiana and other hosts in areas where bullfrog have been introduced.

Surface Ultrastructure and Molecular Studies of Clinostomum complanatum (Rudolphi, 1814) Braun, 1899 (Trematoda: Clinostomidae) Metacercariae in some Freshwater Fishes from Sulaimani Province, Iraq

Clinostomum is a trematode genus in the family Clinostomidae. The mentioned trematode species is parasitizing many fish species as intermediate hosts, while piscivorous birds and mammals are the main definitive hosts. Total of 58 metacercariae of Clinostomum larvae were dissected out from 25 infected fish specimens from eight different species from a number of water bodies of Sulaimani Province, Kurdistan Region, Iraq. In this investigation, 959 fish specimens were collected. These includes five cyprinid species: Capoeta trutta (Heckel), C. umbla (Heckel), Carasobarbus kosswigi (Ladiges), Cyprinion macrostomum Heckel and Garra rufa (Heckel), two leuciscid species: Alburnus sellal Heckel and Squalius lepidus Heckel and the mugilid fish Planiliza abu (Heckel). The prevalence of infection for each of these species was 1.8%, 5%, 20%, 1.5%, 1.7%, 4.9%, 4.9% and 1.3%, respectively. The morphology of the Clinostomum metacercariae was studied by using a compound microscope; their ultra-morphology was evaluated with a scanning electron microscopy (SEM); and the molecular analysis were performed by amplifying, sequencing and comparing the ITS1-5.8S-ITS2 and 28S rDNA gene loci from isolated Clinostomum metacercariae. The obtained sequences confirmed that all metacercariae of the Clinostomum, collected during the present study, represented with C. complanatum (Rudolphi, 1814) based on percent identity with sequences in the GenBank subject database. The molecular characterisations of the C. complanatum metacercariae in the present study were deposited in GenBank NCBI.

Echinococcus multilocularis and other zoonotic helminths in red foxes (Vulpes vulpes) from a southern German hotspot for human alveolar echinococcosis

BackgroundWe describe the spatial distribution of Echinococcus multilocularis in its main definitive host, the red fox, and the distribution of human cases of alveolar echinococcosis (AE) within a highly endemic focus in southern Germany (13.7–19.9/100,000 in 1992–2018). Human cases were unequally distributed within the endemicity focus. The purpose of the study was to test whether this is reflected in the small-scale distribution of E. multilocularis in foxes.MethodsThree areas with contrasting numbers of human cases were selected within the counties of Ravensburg and Alb-Donau, Baden-Württemberg, Germany. From 2018 to 2020, a total of 240 fox carcasses were obtained from traditional hunters in these areas. Carcasses were necropsied and examined for the presence of intestinal helminths. The statistical analysis was performed with SAS version 9.4, and the geo-mapping with QGIS version 3.16.0 Hannover.ResultsThe prevalence of E. multilocularis in foxes was 44/106 (41.5%) in area I (commune Leutkirch and environs), 30/59 (50.8%) in area II (commune Isny and environs), and 31/75 (41.3%) in area III (commune Ehingen and environs). From 1992 to 2018, a total of nine human cases of alveolar echinococcosis were recorded in area I, five cases were recorded in study area III, and no cases were recorded in area II. No statistically significant differences between the areas were observed (P > 0.05) for intestinal infections with E. multilocularis, and no apparent spatial correlation with the small-scale distribution of human cases was found. Concerning other zoonotic helminths, Toxocara spp. were equally common, with prevalence of 38.7%, 47.4% and 48.0%, respectively, while the frequency of Alaria alata varied among the study areas (0.0–9.4%), probably reflecting the specific habitat requirements for the establishment of its complex life cycle.ConclusionsEchinococcus multilocularis is highly prevalent in foxes in all the studied areas. The varying number of human AE cases within these areas should therefore be caused by factors other than the intensity of parasite transmission in foxes.Graphical

Detection of Anti-Neospora caninum Antibodies on Dairy Cattle Farms in Southern Italy.

Neosporosis is recognized as one of the major causes of bovine abortion worldwide. Canids are the main definitive host for this parasite and the presence of dogs in the farm is an important factor for the Neospora caninum infection in bovines. Since, in the province of Lecce, located in the Apulia region of Southern Italy, there are no studies showing the presence of the infection in farm animals, the objective was to perform a serological evaluation for anti-N. caninum antibodiesin serum from 706 dairy cattle and 21 farm dogs located in 40 farms uniformlydistributed over the territory.The presence of N. caninum infection was confirmed in 90.0% (36/40) of the 40 farms examined. The results obtained on all serum samples by an enzyme-linked immunosorbent assay (ID Screen® Neospora caninum competition ELISA kit) for anti-N. caninum antibodies showed a seropositivity rate of 21.1% (149/706) among dairy cows, with a statistically significant higher percentage of positive subjects in the animals over two years old and a positivity rate of 42.9% (9/21) in tested dogs. The obtained data confirmed the presence of neosporosis even in the Lecce area, where it could therefore represent an important cause of abortion and economic losses.

The phylogeographic puzzle of Pseudoacanthocephalus toshimai, an amphibian acanthocephalan in northern Japan.

The amphibian acanthocephalan, Pseudoacanthocephalus toshimai, was considered to be an island-endemic species in Hokkaido, Japan. However, the parasite was found from Rana ornativentris, Rana tagoi, Zhangixalus arboreus, and Bufo japonicus formosus in northern Honshu (Aomori and Iwate Prefectures), which is separated from Hokkaido by the Tsugaru Strait. The mitochondrial DNA-based phylogenetic and population genetic analyses of P. toshimai showed that the northern Honshu isolates are far distantly related to the Hokkaido isolates, and that a demographic population expansion occurred in Hokkaido during the recent geological past. The rich genetic diversity of P. toshimai in northern Honshu suggests a scenario that anuran hosts invaded Hokkaido together with P. toshimai via the land bridge of the Tsugaru Strait. However, the evolutionary history of Rana pirica, a main definitive host for P. toshimai in Hokkaido, is contradictory to the introduction scenario inferred from the parasite. The finding of several geographically mismatched isolates of P. toshimai from both northern Honshu and Hokkaido suggests a possibility that the migration of the parasite infrequently occurred between the two areas even after the land bridge disappeared. More detailed information on the evolutionary history of anurans is needed to resolve the biogeographical enigma of P. toshimai.

Deep amplicon sequencing highlights low intra-host genetic variability of Echinococcus multilocularis and high prevalence of the European-type haplotypes in coyotes and red foxes in Alberta, Canada.

Echinococcus multilocularis (Em) is a zoonotic parasite considered a global emergent pathogen. Recent findings indicate that the parasite is expanding its range in North America and that European-type haplotypes are circulating in western Canada. However, genetic analyses are usually conducted only on a few parasites out of thousands of individuals within each definitive host, likely underestimating the prevalence of less common haplotypes. Moreover, mixed infections with several mtDNA haplotypes in the same host have been reported, but their relative abundance within the host was never estimated. We aimed to 1) estimate the frequency of co-infections of different Em haplotypes in coyotes (Canis latrans) and red foxes (Vulpes vulpes) from western Canada and their relative abundance within the definitive hosts, 2) detect less prevalent haplotypes by sampling a larger proportion of the parasite subpopulation per host, and 3) investigate differences in the distribution of Em haplotypes in these main definitive hosts; foxes and coyotes. We extracted DNA from ~10% of the worm subpopulation per host (20 foxes and 47 coyotes) and used deep amplicon sequencing (NGS technology) on four loci, targeting the most polymorphic regions from the mitochondrial genes cox1 (814 bp), nad1 (344 bp), and cob (387 bp). We detected the presence of mixed infections with multiple Em haplotypes and with different Echinococcus species including Em and E. granulosus s.l. genotypes G8/G10, low intraspecific diversity of Em, and a higher abundance of the European-type haplotypes in both hosts. Our results suggest a population expansion of the European over the North American strain in Alberta and a limited distribution of some European-type haplotypes. Our findings indicate that deep amplicon sequencing represents a valuable tool to characterize Em in multiple hosts, to assess the current distribution and possible origins of the European strain in North America. The potential use of next-generation sequencing technologies is particularly important to understand the patterns of geographic expansion of this parasite.

Incidence of alveolar echinococcosis in humans and animals in Kostanay region of the Republic of Kazakhstan

The research aims to study the spread of alveococcosis in humans and animals on the territory of the Kostanay region of the Republic of Kazakhstan. Studies on the diagnosis of alveococcosis in humans were conducted in the branch of the Ministry of Health of the Republic of Kazakhstan "Scientific-practical center of sanitary-epidemiological examination and monitoring", Kostanay, in 2010-2019. To determine the degree of invasion by alveococcosis, a pathoanatomic autopsy was performed on captured mouse-like rodents in the territory of the Kostanay region, where cases of human alveococcosis were registered. The incidence among the population of various age groups in the region was analyzed based on the results of blood samples by enzyme immunoassay (ELISA) and liver ultrasound. It is established that alveococcosis is a common disease among people living not only in the Kostanay region but also in the Republic of Kazakhstan in general. The main definitive hosts in the development cycle of the pathogen infestation on the territory of the Republic of Kazakhstan are foxes and dogs, intermediate hosts – 18 species of rodents, and for humans, alveococcosis is one of the most dangerous helminthic diseases, since in most cases it leads to death. Alveococcosis can be attributed to particularly dangerous infestations since the foci of infestation are formed not only in anthropogenic zones where the pathogen can devastate but also in natural biocenoses, where the main sources of the pathogen's spread in the external environment are foxes (Vulpes) and corsac foxes (Vulpes corsac). The maximum number of cases of alveococcosis in 2018-2020 was registered in intermediate hosts – mouse-like rodents, like common vole Microtus arvalis, the extent of A. multilocularis invasion was 3.1-3.5%. Based on the comparative analysis of the epizootic and epidemiological situation of alveococcosis in the territory of the Kostanay region, it should be noted that the risk of infection of the population with alveococcosis persists in all areas of the region.

The First Data on Parasites of Monkey Goby Neogobius fluviatilis (Perciformes, Gobiidae) in the Saratov Reservoir

The parasite fauna of the monkey goby Neogobius fluviatilis has been studied from the lower part of the Saratov Reservoir. Six species of parasites are recorded, for one of which (the goby-specific plerocercoid Triaenophorus crassus) the monkey goby is recorded as an additional host for the first time. The 100% invasion of the goby by the alien fluke Nicolla skrjabini makes it possible to attribute it to the main definitive hosts of the parasite in the water body.

Taeniid cestodes in Tibetan foxes (Vulpes Ferrilata) detected by copro-PCR: Applications and challenges

Tibetan foxes (Vulpes ferrilata) have been confirmed as the main wild definitive hosts in echinococcosis transmission in the eastern Tibetan Plateau. However, little information is available about the epidemiology in wildlife from the perspective of the Taeniidae family, which is essential knowledge in understanding the epidemiology and phylogeography of cestode species in the Tibetan plateau. Therefore, in this study, we used copro-PCR techniques, by amplifying nad1 and cox1 gene fragments, to detect the taeniid species from Tibetan fox feces collected in Shiqu County, (Sichuan Province, China), eastern Tibetan Plateau. Phylogenetic relationships between amplified sequences and existed Taenia species genotypes were evaluated. Then, the maximum prevalence (positive PCR results from at least one primer pair) and the conservative prevalence (positive PCR results from at least two primer pairs) were calculated. Thirty-six Tibetan fox feces were analyzed. Echinococcus multilocularis (conservative prevalence ± 95% CI: 22.2% ± 13.6%; maximum prevalence ± 95% CI: 33.3% ± 15.4%) and E. shiquicus (2.8 ± 5.4%; 8.3 ± 9.0%) was detected. Meanwhile, DNA fragments of T. polyacantha were detected with high similarity to NCBI sequences (cox1, 94.0%) and to the larva sample DNA sequenced in this study (93.4%), and were supported by phylogenetic analysis. Thus, T. polyacantha might infect Tibetan foxes (5.6% ± 7.5%, 11.1% ± 10.3%). Our limited findings in the epidemiology of parasitic Taenia species suggest that sylvatic transmission cycles for a more species-rich Taeniid community must be established between wild canids and small mammals than just for the two Echinococcus species. Besides, discrepancies in different primer pairs in detecting the taeniid species were evaluated. The sensitivity of some widely used universal primer pairs was poor in detecting Taenia species from canid copro-DNA samples. It is still challenging to the development of effective taeniid species-specific molecular markers especially for non-zoonotic species.

The effects of dog management on Echinococcus spp. prevalence in villages on the eastern Tibetan Plateau, China

BackgroundThe pastoral area of the eastern Tibetan Plateau is highly endemic for human echinococcosis. Domestic dogs are the main definitive host for the transmission of both Echinococcus granulosus (sensu lato) and E. multilocularis to humans. To control the infection risks, a national-level canine echinococcosis prevention and control programme has been implemented since 2015 in Shiqu County, Ganze Tibetan Autonomous Prefecture, Sichuan, China. The objective of this study was to evaluate its effect on Echinococcus spp. prevalence in dogs.MethodsWe surveyed 69 households with 84 owned dogs, for dog fecal samples and dog keeping information in the villages of Rizha and Eduoma. A total of 105 dog fecal samples (75 from owned dogs and 30 unknown dog fecal samples) were collected between 2015–2017 to determine Echinococcus spp. prevalence using copro-PCR. Eight variables based on household surveys were included into a logistic regression model for significant risk factors to canine echinococcosis prevalence in dogs.ResultsBetween 2015–2017, the overall Echinococcus spp. copro-DNA prevalence decreased significantly in dogs from 51.2% (2015) to 20.0% (2017) in Rizha, and insignificantly from 11.5% (2016) to 4.3% (2017) in Eduoma. Echinococcus multilocularis was the most prevalent species continually copro-DNA detected during the entire study period, while E. granulosus was rare and not detected in 2017. Echinococcus shiquicus copro-DNA prevalence (a probable non-zoonotic wildlife species) was as high in dogs as that of E. multilocularis, although only detected in 2015 in Rizha. Unleashed dog feces were mainly collected in Rizha in 2015. Although 93.2% of owned dogs were leashed, and the monthly praziquantel dosing rate reached 97%, E. multilocularis infection could still be detected in 11.1% of owned dogs in 2017. Monthly deworming, leashing dogs 24 h per day, and the avoidance of dogs feeding on livestock viscera were significant measures to prevent canine echinococcosis infection in owned dogs.ConclusionsCarrying out a canine echinococcosis prevention and control programme can significantly decrease Echinococcus spp. prevalence. The potential contact between leashed dogs and wild small mammals is still a risk for re-infection of owned dogs with E. multilocularis. This study shows that the long-term application of regular dog treatment with praziquantel in the vast and remote echinococcosis endemic areas of the eastern Tibetan Plateau can reduce transmission in dogs but remains a challenging intervention.

First Record of Eustrongylides excisus (Dorylaimea: Dioctophymatidae) in Fish of the Rybinsk Reservoir

The data on the finding of Eustrongylides excisus in the Rybinsk Reservoir (Yaroslavl oblast, Russia) are presented. Larvae-IV were recorded in 2015 in ruff. The appearance of this nematode in the reservoir is associated with the expansion of the range of cormorant, its main definitive host. E. excisus is one more parasite species exhibiting northward expansion in the Volga Basin.

The current prevalence and diversity of cystic echinococcosis in slaughtered animals in Egypt.

Cystic echinococcosis is a potential zoonotic helminthic disease affect a broad spectrum of mammals including humans worldwide. The economic impact of the disease interestingly requires updated gathering information on the prevalence in slaughtered animals. Accordingly, in the current study, 573 camels, 4300 sheep, and 1235 pigs were surveyed in four Egyptian municipal abattoirs. Among those, 62 (10.82%) camels, 33 (0.77%) sheep and 3 (0.24%) pigs had cystic echinococcosis in lungs, livers and spleen. The diversity of cysts revealed that positive-cystic echinococcosis animals from all species were detected in El-Basatin abattoir. In El-Monieb abattoir, sheep only were infected. In El-Waraa and Beni-Suef abattoirs, cysts were seen in camels only. Infected animals included both sexes. In camels, lungs were the most affected organs, while in sheep, livers were the most abundant. In pigs, hydatid cysts were detected only in lungs. Moreover, camel cysts were mostly large-sized (diameter > 10cm) with smaller cysts are also recorded. In sheep, small-, moderately- and large-sized cysts were equally present. Cysts in pigs were large-sized. Camels showed a higher percentage of fertile cysts (46.77%; 29/62) followed by sheep (21.21%; 7/33). Calcified/degenerated cysts were less in camels (38.71%; 24/62) than in sheep (75.76%). Non-viable cysts were the less frequent in both species (14.52% in camels and 3.03% in sheep). All cysts recovered from pigs were fertile. In Egypt, governmental agencies and veterinary authorities are asked to potentially eradicate stray dogs (the main definitive host) and towards the proper hygienic disposal of infected offal in abattoirs to minimize the prevalence of cystic echinococcosis.

Are golden jackals (Canis aureus) definitive hosts for Angiostrongylus vasorum?

Angiostrongylosis caused by Angiostrongylus vasorum is an emerging disease in Europe. Recent reports have shown that, besides the red fox (Vulpes vulpes) recognized as the main definitive host and reservoir for the parasite, the role of the definitive host can be taken by a range of mammals. We considered that, due to the rapid large-scale expansion of its populations in Europe, the golden jackal (Canis aureus) could assume an important role in the epidemiology of the disease. The aim of the investigations was to explore the role of the golden jackal as the definitive host for A.vasorum. Sixty-three golden jackals, legally hunted in lowlands around the Danube River in Serbia recognized as the core area of the species' distribution in Europe, were subjected to patho-morphological and parasitological examination. The adult forms of A.vasorum were detected in the pulmonary arteries in six golden jackals with gross lesions manifested in the lungs. The finding of first stage larvae (L1) of A.vasorum in microscopic smears of the lung tissue altered by infection, which was consistent with the presence of adult parasites and manifestation of gross lesions in the lungs, confirms the successful reproduction of the parasite in the golden jackal. Migration of L1 from the blood vessels to the airways was confirmed by histopathology and, subsequently, their shedding was demonstrated by the Baermann method. The results support the hypothesis that the golden jackal acts as a suitable definitive host for A.vasorum. As a definitive host with a large-scale expansion of its populations in Europe, the golden jackal may be an important part of the parasite's host repertoire by spreading the parasite into previously non-endemic areas and by being an additional definitive host in endemic areas of vulpine angiostrongylosis.

Dirofilariasis canina: una parasitosis emergente favorecida por el cambio climático

Dirofilaria Immitis is a zoonotic parasitosis produced by a nematode responsible for generating, in infected animals, potentially fatal cardiopulmonary disease. The dirofilariosis occurs in warm areas, with moisture, beeing the mosquito the vector responsible for its transmission. Despite its denomination, it is a mainly pulmonary disease, affecting the cardiac part in advanced stages. It has different larval stages, but stage L3 is infectious. It enters the host through the vector bite and begins to develop to adult stages which are located at the pulmonary arteries. The main definitive host and reservoir is the dog, but it can affect other wild canids like the fox. The clinical signs range from exercise intolerance, coughing, respiratory crackles and as the parasitic load progresses and increases, hemoptysis or epistaxis, weight loss, syncopes, may occur. In order to arrive at its diagnosis, the detection of microfilariae is essential, whether by taking blood smears from microhematocrit tubes or by the Knott test. Its treatment consists in, the elimination of the young filariae by the administration of macrocyclic lactones and then the use of an adulticide drug, melarsomine diclohydrate. The climatic changes that have occurred in the last time are of concern due to their propagation towards the north of Patagonia, and particularly to our province of La Pampa.

Differential patterns of definitive host use by two fish acanthocephalans occurring in sympatry: Pomphorhynchus laevis and Pomphorhynchus tereticollis.

Parasites with complex life-cycles and trophic transmission are expected to show low specificity towards final hosts. However, testing this hypothesis may be hampered by low taxonomic resolution, particularly in helminths. We investigated this issue using two intestinal fish parasites with similar life-cycles and occurring in sympatry, Pomphorhynchus laevis and Pomphorhynchus tereticollis (Acanthocephala). We used species-specific ITS1 length polymorphism to discriminate parasite species from 910 adult acanthocephalans collected in 174 individual hosts from 12 fish species. Both P. laevis and P. tereticollis exhibited restricted host range within the community of available fish host species, and transmission bias compared to their relative abundance in intermediate hosts. The two parasites also exhibited low niche overlap, primarily due to their contrasting use of bentho-pelagic (P. laevis) and benthic (P. tereticollis) fish. Furthermore, parasite prevalence in intermediate hosts appeared to increase with taxonomic specificity in definitive host use. Comparison of P. laevis and P. tereticollis adult size in the two main definitive hosts, barbel and chub, suggested lower compatibility towards the fish species with the lowest parasite abundance, in particular in P. laevis. The determinants of low niche overlap between these two sympatric acanthocephalan species, and the contribution of definitive host range diversity to parasite transmission success, are discussed.

Echinococcus multilocularis in Denmark 2012-2015: high local prevalence in red foxes.

In Western Europe, the Echinococcus multilocularis lifecycle is predominantly sylvatic, typically involving red foxes (Vulpes vulpes) as the main definitive hosts with Microtus spp. and Arvicola spp. as intermediate hosts. During a 4-year surveillance study (2012-2015), Danish red foxes and raccoon dogs (n = 1345) were examined for E. multilocularis. Moreover, 134 insectivores and rodents collected in South Jutland during spring and summer 2016 were examined for the presence of metacestodes. The sedimentation and counting technique and molecular typing were used to identify E. multilocularis infections in the carnivores, while the rodent livers were examined macro- and microscopically for parasite lesions. Following morphological identification of E. multilocularis adult worms, the identity was verified by sequence analysis of the 12S rRNA gene in most cases (n = 13). Echinococcus multilocularis infection was demonstrated in 19 red foxes (Vulpes vulpes) originating from only two specific areas of South Jutland, namely Højer and Grindsted, and in two raccoon dogs (Nyctereutes procyonoides), originating from Højer. In Højer, 28.5% (CI 95% 11.7-45.3) of the examined red foxes were E. multilocularis positive per year. Moreover, positive red foxes were identified each year from 2012 to 2015, while E. multilocularis positive red foxes were only identified in Grindsted in 2013 (4.0%) and 2014 (6.4%). In contrast, all collected rodents were negative for E. multilocularis. We conclude that E. multilocularis is locally endemic in South Jutland with a high local prevalence in Højer.

Spirocercosis in red fox (Vulpes vulpes) in a natural reserve located in a meso-Mediterranean area.

Spirocerca lupi Rudolphi 1809 (Nematoda Spirocercidae) has an indirect cycle involving intermediate and paratenic hosts, having domestic or wild canids as the main definitive hosts. The most frequent pathology affecting dogs is a granulomatous tumor-like growth containing adults in the oesophagus and aorta. There are very few references about the presence of nodules in the stomach. There is scant information about the epidemiology of this disease in wild red foxes in meso-Mediterranean areas. In this work we report on the natural infection of wild red foxes by Spirocerca lupi and the damage produced in the stomach wall in an area where contact with other potential definitive hosts (canids) is very rare. From July 2015 to November 2016, 61 red foxes were sampled. 18.03% of the stomach walls examined had nodules containing Spirocerca lupi adults and eggs. The prevalence of infection was similar for young and adult groups (23.81 and 18.18%; χ2 = 0.25; df = 1; P = 0.6171) and it was higher in females than in males (25.81 versus 10.00%, χ2 = 2.58; df = 1; P = 0.1082). The red fox population in the area seems to be well established judging from their age distribution and the fact that they could be captured all year round. It would appear that in the absence of other main definitive host S. lupi population is able to survive just parasitizing red foxes. Pathologic effects of this parasite on red foxes seems to show some differences related to domestic dogs. These results also indicates as predator control programs can maintain suitable host populations with reduced level of infection.

Mansonellosis: current perspectives.

Mansonellosis is a filarial disease caused by three species of filarial (nematode) parasites (Mansonella perstans, Mansonella streptocerca, and Mansonella ozzardi) that use humans as their main definitive hosts. These parasites are transmitted from person to person by bloodsucking females from two families of flies (Diptera). Biting midges (Ceratopogonidae) transmit all three species of Mansonella, but blackflies (Simuliidae) are also known to play a role in the transmission of M. ozzardi in parts of Latin America. M. perstans and M. streptocerca are endemic in western, eastern, and central Africa, and M. perstans is also present in the neotropical region from equatorial Brazil to the Caribbean coast. M. ozzardi has a patchy distribution in Latin America and the Caribbean. Mansonellosis infections are thought to have little pathogenicity and to be almost always asymptomatic, but occasionally causing itching, joint pains, enlarged lymph glands, and vague abdominal symptoms. In Brazil, M. ozzardi infections are also associated with corneal lesions. Diagnosis is usually performed by detecting microfilariae in peripheral blood or skin without any periodicity. There is no standard treatment at present for mansonellosis. The combination therapy of diethylcarbamazine plus mebendazole for M. perstans microfilaremia is presently one of the most widely used, but the use of ivermectin has also been proven to be very effective against microfilariae. Recently, doxycycline has shown excellent efficacy and safety when used as an antimicrobial against endosymbiotic Wolbachia bacteria harbored by some strains of M. perstans and M. ozzardi. Diethylcarbamazine and ivermectin have been used effectively to treat M. streptocerca infection. There are at present no estimates of the disease burden caused by mansonellosis, and thus its importance to many global health professionals and policy makers is presently limited to how it can interfere with diagnostic tools used in modern filarial disease control and elimination programs aimed at other species of filariae.