Evidence of predation pressure on sensitive species by raccoons based on parasitological studies.

To demonstrate predation and potential impacts of raccoons on various species, a total of 108 raccoons from aquatic-associated nature reserves and natural areas in three federal states of Germany, Hesse (n = 36), Saxony-Anhalt (n = 36) and Brandenburg (n = 36), were investigated from a dietary ecological perspective in the present study. Fecal analyses and stomach content examinations were conducted for this purpose. Additionally, as a supplementary method for analyzing the dietary spectrum of raccoons, the parasite fauna was considered, as metazoan parasites, in particular, can serve as indicators for the species and origin of food organisms. While stomach content analyses allow for a detailed recording of trophic relationships solely at the time of sampling, parasitological examinations enable inferences about more distant interaction processes. With their different developmental stages and heteroxenous life cycles involving specific, sometimes obligate, intermediate hosts, they utilize the food web to reach their definitive host. The results of this study clearly demonstrate that spawning areas of amphibians and reptiles were predominantly utilized as food resources by raccoons in the study areas. Thus, common toad (Bufo bufo), common newt (Lissotriton vulgaris), grass frog (Rana temporaria), and grass snake (Natrix natrix) were identified as food organisms for raccoons. The detection of the parasite species Euryhelmis squamula, Isthmiophora melis, and Physocephalus sexalatus with partially high infestation rates also suggests that both amphibians and reptiles belong to the established dietary components of raccoons from an ecological perspective, as amphibians and reptiles are obligate intermediate hosts in the respective parasitic life cycles of the detected parasites. The study clearly demonstrates that raccoons have a significant impact on occurrence-sensitive animal species in certain areas and, as an invasive species, can exert a negative influence on native species and ecosystems.

The hidden threat: Exploring the parasite burden and feeding habits of invasive raccoon dogs (Nyctereutes procyonoides) in central Europe.

Originally from Asia, the raccoon dog Nyctereutes procyonoides is an invasive alien species in Europe, listed since 2019 on the List of invasive alien species of Union concern. The raccoon dog is considered to have negative impact on native biodiversity, as well as a crucial role in hosting and transmitting diverse parasites and pathogens of human and veterinary importance. In the present study, stomach content analyses and parasitological examinations were performed on 73 raccoon dogs from Germany. In addition, fecal samples were analyzed. The results of the study confirm the assumption that the examined raccoon dogs were infested with a various ecto- and endoparasite fauna. A total of 9 ecto- and 11 endoparasites were detected, with 6 of the endoparasites having human pathogenic potential. Trichodectes canis (P = 53.42%), Toxocara canis (P = 50.68%) and Uncinaria stenocephala (P = 68.49%) were the most abundant parasite species. The stomach contents consisted of approximately one-third vegetable and two-thirds animal components, composed of various species of amphibians, fish, insects, mammals and birds. Among them were specially protected or endangered species such as the grass frog Rana temporaria. The study shows that the raccoon dog exerts predation pressure on native species due to its omnivorous diet and, as a carrier of various parasites, poses a potential risk of infection to wild, domestic and farm animals and humans.

Raccoons contraband - The metazoan parasite fauna of free-ranging raccoons in central Europe.

The invasive raccoon (Procyon lotor) is an abundant carnivore and considered as an important potential vector of infectious diseases and parasites in Europe. Raccoons show a broad, opportunistic, omnivorous food spectrum. Food supply and habitat quality in urban areas are very attractive for the generalist raccoon. This inevitably leads to increased interaction with humans, domestic animals and livestock, making the raccoon a potentially suitable zoonosis vector. In its autochthonous range, especially in the Eastern and Midwestern United States, the raccoon has been studied very intensively since the beginning of the 20th century. Whereas, basic field biology and parasitology studies in Germany and Europe are lacking and have only been conducted sporadically, regionally and on small sample sizes. In the presented study 234 raccoons from central Germany were comprehensively examined for their metazoan parasite fauna. The present study shows for the first time an extremely diverse parasite fauna in raccoons outside their native range and proves their essential role as intermediate hosts and hosts for ecto- and endoparasites. A total of 23 different parasite species were identified, five of which are human pathogens, 14 of which are new for the parasite fauna of raccoons in Europe. The human pathogenic raccoon roundworm Baylisascaris procyonis is the most common parasite species in this study, with a prevalence of up to 95%. The digenetic trematode Plagiorchis muris, another human pathogenic parasite species, was detected for the first time in raccoons. The ongoing spread of invasive carnivores and the associated spread and transmission of their parasites and other pathogens increases the potential health risk of wild and farmed animals as well as humans. An increase in parasitic diseases in humans (e.g. raccoon roundworm) is to be expected, especially in urban areas, where raccoons are becoming more and more abundant.

SARS-CoV-2 and West Nile Virus Prevalence Studies in Raccoons and Raccoon Dogs from Germany.

Unlike farm animals, wild animals are not subject to continuous health surveillance. Individual projects designed to screen wildlife populations for specific pathogens are, therefore, also of great importance for human health. In this context, the possible formation of a reservoir for highly pathogenic zoonotic pathogens is a focus of research. Two of these pathogens that have received particular attention during the last years are the novel severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), due to its fast global spread and high impact to the human health, and, since its introduction into Germany, the flavivirus West Nile virus (WNV). Especially in combination with invasive vertebrate species (e.g., raccoons (Procyon lotor) and raccoon dogs (Nyctereutes procyonoides) in Germany), risk analysis must be done to enable health authorities to assess the potential for the establishment of new wild life reservoirs for pathogens. Therefore, samples were collected from raccoons and raccoon dogs and analyzed for the presence of SARS-CoV-2 and WNV infections in these populations. Molecular biological and serological data obtained imply that no SARS-CoV-2 nor WNV reservoir has been established in these two wild life species yet. Future investigations need to keep an eye on these invasive carnivore populations, especially since the close contact of these animals to humans, mainly in urban areas, would make animal-human transmission a challenge for human health.

Incompletely observed: niche estimation for six frequent European horsefly species (Diptera, Tabanoidea, Tabanidae).

BACKGROUND: More than 170 species of tabanids are known in Europe, with many occurring only in limited areas or having become very rare in the last decades. They continue to spread various diseases in animals and are responsible for livestock losses in developing countries. The current monitoring and recording of horseflies is mainly conducted throughout central Europe, with varying degrees of frequency depending on the country. To the detriment of tabanid research, little cooperation exists between western European and Eurasian countries. METHODS: For these reasons, we have compiled available sources in order to generate as complete a dataset as possible of six horsefly species common in Europe. We chose Haematopota pluvialis, Chrysops relictus, C. caecutiens, Tabanus bromius, T. bovinus and T. sudeticus as ubiquitous and abundant species within Europe. The aim of this study is to estimate the distribution, land cover usage and niches of these species. We used a surface-range envelope (SRE) model in accordance with our hypothesis of an underestimated distribution based on Eurocentric monitoring regimes. RESULTS: Our results show that all six species have a wide range in Eurasia, have a broad climatic niche and can therefore be considered as widespread generalists. Areas with modelled habitat suitability cover the observed distribution and go far beyond these. This supports our assumption that the current state of tabanid monitoring and the recorded distribution significantly underestimates the actual distribution. Our results show that the species can withstand extreme weather and climatic conditions and can be found in areas with only a few frost-free months per year. Additionally, our results reveal that species prefer certain land-cover environments and avoid other land-cover types. CONCLUSIONS: The SRE model is an effective tool to calculate the distribution of species that are well monitored in some areas but poorly in others. Our results support the hypothesis that the available distribution data underestimate the actual distribution of the surveyed species.

An investigation of hibernating members from the Culex pipiens complex (Diptera, Culicidae) in subterranean habitats of central Germany.

The Culex pipiens complex encompasses five species and subspecies of the genus Culex. Over time, a multitude of morphologically indistinguishable species has been assigned to this complex with several species being classified as important vectors for different diseases. Some species of this complex hibernate in subterranean habitats, and it has been proven that viruses can survive this phase of hibernation. However, studies focusing on the environmental requirements, ecology and spatial and temporal distribution patterns of mosquitos in underground habitats are sparse. Here, we investigate the main environmental factors and dependencies of Culex, considering the number of individuals and survival probabilities in underground habitats during the winter months. Methods. Since the State of Hesse, Germany harbors about 3500 to 4000 subterranean shelters ample availability of subterranean habitats there provides a good opportunity to conduct detailed investigations of the Culex pipiens complex. In this study, we identified a sample of 727 specimens of overwintering females within the Culex pipiens complex from 52 different underground sites collected over a period of 23 years using qPCR. A complete data set of samplings of hibernating mosquitos from 698 subterranean habitats in Central Germany over the same period was available to study the spatial and temporal patterns and the effect of temperature and precipitation conditions on these hibernating populations using a generalized linear model (GLM). Results. Our qPCR-results show, similar to aboveground studies of mosquitos, that Culex pipiens pipiens and Culex torrentium occur sympatrically. On the other hand, Culex pipiens molestus occurred very rarely. The GLM revealed no shifts in species composition over time, but different preferences for subterranean hibernacula, chemical effects on overwintering populations as well as effects of annual and seasonal mean temperature and precipitation during the active phase from March to November. Cx. p. pipiens and Cx. torrentium are the most common species within Hessian caves and other underground habitats during winter. They co-occur with different frequency without any patterns in species composition. Weather conditions influence the number of overwintering mosquitos during the activity phase. Depending on cave parameters, the number of mosquitos decreases during the winter months.

Spatial and temporal patterns of human Puumala virus (PUUV) infections in Germany.

BACKGROUND: Worldwide, the number of recorded human hantavirus infections as well as the number of affected countries is on the rise. In Europe, most human hantavirus infections are caused by the Puumala virus (PUUV), with bank voles (Myodes glareolus) as reservoir hosts. Generally, infection outbreaks have been related to environmental conditions, particularly climatic conditions, food supply for the reservoir species and land use. However, although attempts have been made, the insufficient availability of environmental data is often hampering accurate temporal and spatially explicit models of human hantavirus infections. METHODS: In the present study, dynamics of human PUUV infections between 2001 and 2015 were explored using ArcGIS in order to identify spatio-temporal patterns. RESULTS: Percentage cover of forest area was identified as an important factor for the spatial pattern, whereas beech mast was found explaining temporal patterns of human PUUV infections in Germany. High numbers of infections were recorded in 2007, 2010 and 2012 and areas with highest records were located in Baden-Wuerttemberg (southwest Germany) and North Rhine-Westphalia (western Germany). CONCLUSION: More reliable data on reservoir host distribution, pathogen verification as well as an increased awareness of physicians are some of the factors that should improve future human infection risk assessments in Germany.

Correction to: Flammability testing of 22 conventional European pediculicides.

The original publication of this paper contains an error.

Three new species of Carychium O.F. Müller, 1773 from the Southeastern USA, Belize and Panama are described using computer tomography (CT) (Eupulmonata, Ellobioidea, Carychiidae).

Three new species of the genus Carychium O.F. Müller, 1773, Carychium hardiei Jochum & Weigand, sp. n., Carychium belizeense Jochum & Weigand, sp. n. and Carychium zarzaae Jochum & Weigand, sp. n. are described from the Southeastern United States, Belize and Panama, respectively. In two consecutive molecular phylogenetic studies of worldwide members of Carychiidae, the North and Central American morphospecies Carychium mexicanum Pilsbry, 1891 and Carychium costaricanum E. von Martens, 1898 were found to consist of several evolutionary lineages. Although the related lineages were found to be molecularly distinct from the two nominal species, the consequential morphological and taxonomic assessment of these lineages is still lacking. In the present paper, the shells of these uncovered Carychium lineages are assessed by comparing them with those of related species, using computer tomography for the first time for this genus. The interior diagnostic characters are emphasized, such as columellar configuration in conjunction with the columellar lamella and their relationship in context of the entire shell. These taxa are morphologically described and formally assigned their own names.

Flammability testing of 22 conventional European pediculicides.

Lice have been parasitizing humans for at least 10,000 years. Since then, humans have tried to rid themselves of these unpleasant and potentially disease-carrying insects. Despite various plant extracts and chemical compounds being used to combat recurring infestations to this date, several lice populations have developed resistance to some of the abundantly used compounds. This resulted in the development of anti-louse products that physically kill the different lice stages. Today, a widely used group of delousing agents are dimethicones (polydimethylsiloxane PDMS) which function by suffocating the lice. However, many dimethicones and related products are highly flammable which makes them potentially dangerous for treatment. In the present study, we tested the flammability of 22 delousing agents in order to shed some light onto this currently unresolved problem in the product design of pediculicides. Thirteen products were easily ignitable, some even by distant contact with a sparkler.

Modeling the habitat suitability for the arbovirus vector Aedes albopictus (Diptera: Culicidae) in Germany.

Climatic changes raise the risk of re-emergence of arthropod-borne virus outbreaks globally. These viruses are transmitted by arthropod vectors, often mosquitoes. Due to increasing worldwide trade and tourism, these vector species are often accidentally introduced into many countries beyond their former distribution range. Aedes albopictus, a well-known disease vector, was detected for the first time in Germany in 2007, but seems to have failed establishment until today. However, the species is known to occur in other temperate regions and a risk for establishment in Germany remains, especially in the face of predicted climate change. Thus, the goal of the study was to estimate the potential distribution of Ae. albopictus in Germany. We used ecological niche modeling in order to estimate the potential habitat suitability for this species under current and projected future climatic conditions. According to our model, there are already two areas in western and southern Germany that appear suitable for Ae. albopictus under current climatic conditions. One of these areas lies in Baden-Wuerttemberg, the other in North-Rhine Westphalia in the Ruhr region. Furthermore, projections under future climatic conditions show an increase of the modeled habitat suitability throughout Germany. Ae. albopictus is supposed to be better acclimated to colder temperatures than other tropical vectors and thus, might become, triggered by climate change, a serious threat to public health in Germany. Our modeling results can help optimizing the design of monitoring programs currently in place in Germany.

Cooling water of power plant creates "hot spots" for tropical fishes and parasites.

Thermally altered water bodies can function as "hot spots" where non-native species are establishing self-sustaining populations beyond their tropical and subtropical native regions. Whereas many tropical fish species have been found in these habitats, the introduction of non-native parasites often remains undetected. Here, n = 77 convict cichlids (Amatitlania nigrofasciata) were sampled by electro-fishing at two sites from a thermally altered stream in Germany and examined for parasite fauna and feeding ecology. Stomach content analysis suggests an opportunistic feeding strategy of A. nigrofasciata: while plant material dominated the diet at the warm water inlet (∼30 °C), relative contributions of insects, plants, and crustaceans were balanced 3 km downstream (∼27 °C). The most abundant non-native parasite species was the tropical nematode Camallanus cotti with P = 11.90 % and P = 80.00 % at the inlet and further downstream, respectively. Additionally, nematode larvae of Anguillicoloides crassus and one specimen of the subtropical species Bothriocephalus acheilognathi were isolated. A. nigrofasciata was also highly infected with the native parasite Acanthocephalus anguillae, which could be linked to high numbers of the parasite's intermediate host Asellus aquaticus. The aim of this study was to highlight the risk and consequences of the release and establishment of ornamental fish species for the introduction and spread of non-indigenous metazoan parasites using the convict cichlid as a model species. Furthermore, the spread of non-native parasites into adjacent fish communities needs to be addressed in the future as first evidence of Camallanus cotti in native fish species was also found.

Hyperparasitism of mosquitoes by water mite larvae.

Hyperparasitism of ectoparasitic water mite larvae on mosquitoes is still a neglected relationship and was investigated only in a few studies. We analysed 2313 female mosquitoes from six different sampling localities with regard to their degree of parasitism with water mite larvae. In total, we found 38 mosquito individuals parasitized by 93 water mite larvae, ranging from 1 to 12 larvae per mosquito. Water mite larvae detected are members of the two species Parathyas cf. barbigera (n = 92) and Arrenurus cf. globator (n = 1). Out of the analysed mosquitoes, individuals out of the species Aedes vexans, Anopheles claviger, Ochlerotatus communis, the Ochlerotatus cantans/annulipes group, Ochlerotatus cataphylla and Ochlerotatus sticticus were tested to be parasitized by water mite larvae. The highest prevalence was found within the species Oc. cataphylla (28.6 %) and Oc. cantans/annulipes (21.7 %). No water mite larvae were found, e.g. on individuals of Aedes cinereus, Coquillettidia richiardii, the Culex pipiens/torrentium group, Ochlerotatus caspius, Ochlerotatus dorsalis or Ochlerotatus punctor. All of the attachment sites were located between the neck and abdomen with the ventral thorax site being the most frequent one.

Modeling of the putative distribution of the arbovirus vector Ochlerotatus japonicus japonicus (Diptera: Culicidae) in Germany.

Today, international travel and global freight transportation are increasing and have a direct influence on the introduction and establishment of non-native mosquito species as well as on the spread of arthropod (mosquito)-borne diseases inside Europe. One of the mosquito species that has become invasive in many areas is the Asian rock pool or bush mosquito Ochlerotatus japonicus japonicus (synonyms: Aedes japonicus japonicus or Hulecoeteomyia japonica japonica). This species was detected in Germany in 2008 for the first time. Until today, three different Oc. j. japonicus populations have been documented. Laboratory studies have shown that Oc. j. japonicus can act as a vector for a variety of disease agents. Thus, the knowledge on its current distribution is essential for different measurements. In the present study, ecological niche models were used to estimate the potential distribution of Oc. j. japonicus in Germany. The aim was to detect areas within Germany that could potentially function as habitats for this species. According to our model, areas in western, southern, and central Germany offer suitable conditions for the mosquito and may therefore be at risk for an invasion of the species. We strongly suggest that those areas should be monitored more intensively in the future. For this purpose, it would also be essential to search for possible dispersal routes as well as for natural barriers.