Fatal infection with Versteria sp. in a muskrat, with implications for human health

The Taeniidae tapeworms are a family of helminths that have a similar life cycle, with intermediate hosts developing characteristic cysts in visceral organs. We describe here a case in Pennsylvania, USA, of fatal Versteria infection in a muskrat ( Ondatra zibethicus), which, to our knowledge, has not been reported to develop disease associated with infection. Postmortem examination revealed widespread tissue loss and replacement by solid-bodied cestode larvae with minimal adjacent inflammation in many visceral organs, most severe in the lungs, liver, and brain. Key morphologic features via histology included cephalic structures and short rostellar hooklets, which are characteristic for the genus. Genetic characterization confirmed the cestode as being an undescribed lineage of Versteria that has been implicated as the cause of severe morbidity and mortality in humans and nonhuman primates in North America. Considering the zoonotic significance of this pathogen, our report expands on the limited literature regarding disease caused by Versteria and emphasizes the need to identify the causative tapeworm more accurately, especially in rodent intermediate hosts given that previous reports do not have molecular confirmation of species.

Surveillance for diseases, pathogens, and toxicants of muskrat (Ondatra zibethicus) in Pennsylvania and surrounding regions

Using diagnostic data and contemporary sampling efforts, we conducted surveillance for a diversity of pathogens, toxicants, and diseases of muskrats (Ondatra zibethicus). Between 1977 and 2019, 26 diagnostic cases were examined from Kansas and throughout the Southeast and Mid-Atlantic, USA. We identified multiple causes of mortality in muskrats, but trauma (8/26), Tyzzer’s disease (5/6), and cysticercosis (5/26) were the most common. We also conducted necropsies, during November 2018—January 2019 Pennsylvania muskrat trapping season, on 380 trapper-harvested muskrat carcasses after the pelt was removed. Tissue samples and exudate were tested for presence of or exposure to a suite of pathogens and contaminants. Gastrointestinal tracts were examined for helminths. Intestinal helminths were present in 39.2% of necropsied muskrats, with Hymenolepis spp. (62%) and echinostome spp. (44%) being the most common Molecular testing identified a low prevalence of infection with Clostridium piliforme in the feces and Sarcocystis spp. in the heart. We detected a low seroprevalence to Toxoplasma gondii (1/380). No muskrats were positive for Francisella tularensis or Babesia spp. Cysticercosis was detected in 20% (5/26) of diagnostic cases and 15% (57/380) of our trapper-harvested muskrats. Toxic concentrations of arsenic, cadmium, lead, or mercury were not detected in tested liver samples. Copper, molybdenum, and zinc concentrations were detected at acceptable levels comparative to previous studies. Parasite intensity and abundance were typical of historic reports; however, younger muskrats had higher intensity of infection than older muskrats which is contradictory to what has been previously reported. A diversity of pathogens and contaminants have been reported from muskrats, but the associated disease impacts are poorly understood. Our data are consistent with historic reports and highlight the wide range of parasites, pathogens and contaminants harbored by muskrats in Pennsylvania. The data collected are a critical component in assessing overall muskrat health and serve as a basis for understanding the impacts of disease on recent muskrat population declines.

Invasive alien mammals of European Union concern

ABSTRACTBiological invasions have emerged as one of the main drivers of biodiversity change and decline, and numbers of alien species are rapidly rising. The European Union established a dedicated regulation to limit the impacts of invasive alien species (IAS), which is focused on a Union List of IAS of particular concern. However, no previous study has specifically addressed the ecology of invasive alien mammals included in the Union List.We performed a systematic review of published literature on these species. We retrieved 262 studies dealing with 16 species, and we complemented these with the most up-to-date information extracted from global databases on IAS.We show that most of the study species reached Europe as pets that escaped from captivity or were intentionally released. On average, 1.2 species’ new first records/year were documented in European countries in the period 1981-2020, and most species are still expanding their alien ranges colonising neighbouring territories. France, Germany, Italy, and The Netherlands are the most invaded nations, and the muskrat (Ondatra zibethicus), the raccoon dog (Nyctereutes procyonoides), and the American mink (Neovison vison) are the most widespread species, having invaded at least 27 countries each. Invasive mammals of European Union concern are threatening native biodiversity and human well-being: worryingly, 81.3% of the study species are implicated in the epidemiological cycle of zoonotic pathogens.Containing the secondary spread to further countries is of paramount importance to avoid the establishment of new populations of invasive mammals and the related impacts on native communities, ecosystem services, and human health.Our results offer the most updated compendium on the ecology of invasive mammals of European Union concern, that can be used to assist environmental policies, identify and subsequently fill knowledge gaps, and inform stakeholders.GRAPHICAL ABSTRACTGraphical abstract: Invasive alien mammals of European Union concern.The figure illustrates how the introduction of a species in few new areas, followed by a lag phase of adaptation and sometimes enriched by further subsequent releases, can rapidly lead to the colonisation of large parts of a continent. On the top left, a heat map with species’ richness in countries of Europe. On the top right, a word cloud with the main keywords of our literature search and some of the study species’ names. On the bottom left, four out of 16 study species: in clockwise order, the raccoon dog (Nyctereutes procyonoides), the muskrat (Ondatra zibethicus), the American mink (Neovison vison), and the raccoon (Procyon lotor). On the bottom right, the temporal distribution of the first records of the study species in the countries of Europe.

Assessment of the morphological parameters of the muskrat population living in the Ile-Balkhash basin

Over the past decade, no studies have been conducted on the distribution, number, and structure of muskrats (ondatra zibethicus) in Kazakhstan. Muskrat fur is a valuable fur. However, at present, the very small number of ondatra zibethicus, the decline in its population, leads to changes in biodiversity for Kazakhstan and a number of countries. The purpose of the work is a comprehensive study of the habitat of muskrats, morphological indicators of the population of muskrats living in the Ili - Balkhash rivers and lakes. The article provides data on studies of the life of muskrats and the distribution of muskrats, considers the distribution, number, density and reasons that affect the current state of the muskrats (ondatra zibethicus) in the system of the Ili-Balkhash basins. The age and sex composition of the Muskrat selection in the Ili-Balkhash basin system, body weight and size of adult muskrats of Southern Balkhash are indicated. Initially, the Muskrat had no natural enemies, as well as pathogens, so the number of muskrats increased intensively. For muskrats to reproduce, a small amount of time is enough. However, recently, the number of muskrats has been declining, as the large number of muskrats, changes in the composition of food, and the feeding of muskrats by predatory animals have led to a decrease in the number of muskrats. The Ili-Balkhash Basin is home to a large number of muskrats, because in the Ili-Balkhash Basin there are many lakes, streams, riverbeds, which are rich in the necessary food reserves for muskrats and are convenient for the construction of Burrows and burial grounds. Acclimatization of muskrats in Kazakhstan to use free land and ecological biotopes in the national economy is a method aimed at changing and enriching the fauna.