High overlap of zoonotic helminths between wild mammalian predators and rural dogs - an emerging One Health concern?

The concept of One Health emphasizes the interdependence of human, animal and environmental health and is of growing significance, in part owing to the problems related to emerging infectious diseases of wildlife origin. Wild mammalian predators are a potential risk factor for transmission of zoonotic pathogens to domesticated animals and humans. This is especially relevant in rural areas, where transmission of zoonotic pathogens can occur particularly efficiently when free-ranging dogs are present. The main aim of this study was to determine helminth infections among wild mammalian predators and evaluate the overlap between helminth faunas of wild mammals and dogs. Scat samples of predators were collected in coastal areas of Western Estonia and genetic methodology applied for the correct identification of predator species from their scat. Parasitic helminths of mammalian predators in the scat samples were analysed and compared with dog data from a previous study. High helminth prevalence (~90%) was found in dominant predator species in the area, namely the red fox (Vulpes vulpes) and golden jackal (Canis aureus). Moreover, the helminth fauna of both wild species, including potentially zoonotic helminths, overlapped largely with that of rural dogs in the same area. The results, together with the ones from earlier parasitological studies among humans in Estonia, emphasize the potential risk of pathogen transmission from wild mammalian predators to dogs and from dogs to humans, making parasitic diseases of wildlife a One Health concern.

Cardiorespiratory nematodes and co-infections with gastrointestinal parasites in new arrivals at dog and cat shelters in north-western Spain

Metastrongyloid and trichuroid cardiorespiratory nematodes of dogs and cats are considered emergent in several European countries, and an increase in the number and extent of endemic foci has been described. Since data on their prevalence are limited in this continent, faecal samples from new arrivals (365 dogs and 65 cats) at two animal shelters in North-western Spain were analysed using both floatation and Baermann techniques. In order to confirm the microscopic identification of Metastrongylidae first stage larvae, molecular characterization based on the sequence of the ITS-2 was performed. The possible influence of some variables such as the species, sex and age of the animals and the co-infection with other gastrointestinal parasites on the prevalence of cardiorespiratory nematodes was analysed. The most prevalent metastrongylid was Aelurostrongylus abstrusus (15.4%) followed by Angiostrongylus vasorum (4.1%) and Crenosoma vulpis (1.1%). Regarding trichuroids, Eucoleus aerophilus and/or Eucoleus boehmi eggs were detected in 28 dogs (7.7%) and four cats (6.2%). Almost all animals positive to cardiorespiratory nematodes (86.8%) were co-infected with gastrointestinal parasites. The prevalence of Metastrongylidae and respiratory trichuroids was significantly higher in dogs co-infected with Taenia spp. and Toxocara canis or Giardia duodenalis and Sarcocystis spp., respectively. In cats, a significant higher prevalence of Metastrongylidae nematodes was found in animals co-infected with Toxocara cati. Our results reveal that cardiorespiratory nematodes are common in companion animals from north-western Spain, showing higher prevalences than those previously reported from this country. This investigation represents the first report of C. vulpis, E. aerophilus and E. boehmi in dogs from Spain. The identification of a number of zoonotic parasites is of public health concern. Our results indicate that these nematodes should be included in the differential diagnosis of dogs and cats from north-western Spain showing respiratory or cardiac clinical signs.

Protozoan and Helminth Infections of Aviary-Reared Alectoris rufa (Galliformes: Phasianidae) before Releasing for Hunting in the Czech Republic: Infection Dynamics and Potential Risks

Age-related dynamics of protozoan and helminth infections in the red-legged partridge, Alectoris rufa, were studied in an intensive breeding aviary in the Czech Republic before releasing birds for hunting purposes. Pooled fecal samples (n = 900) were examined over 3 rearing seasons (2012-2014). A total of 4 protozoan species, Cryptosporidium baileyi, Cryptosporidium meleagridis, Eimeria kofoidi, and Eimeria legionensis, and 4 helminths, Capillaria phasianina, Eucoleus perforans, Heterakis gallinarum, and Syngamus trachea, was found. The most common parasite was S. trachea (prevalence 20-26%) in dead birds (n = 99), which represents a high risk for breeders. Co-occurrence of protozoans and helminths indicated similarities in infection dynamics throughout the 3 breeding seasons. Mixed infections of Cryptosporidium baileyi and C. meleagridis with other parasitic species are reported for the first time. Our findings provide new insights into breeding of A. rufa and may help to improve the efficacy of disease control strategies and prevention, especially with the potential for spreading of parasitic infections to wildlife through released birds into open areas.

Ventral dermatitis in rowi (Apteryx rowi) caused by cutaneous capillariasis

In 2013 there was an outbreak of crusting ventral dermatitis among a group of juvenile rowi (Apteryx rowi), a species of the endangered New Zealand kiwi, that were being raised on an off-shore island sanctuary. Biopsies taken at the time found nematodes migrating within the epidermis of affected skin but the specific identity and origin of the organisms was not established, and sporadic cases of similar skin disease continue to occur on the island. On examination of additional sections from the original skin biopsies, adult nematodes and eggs were identified, the histomorphology of which was consistent with Capillaria sensu lato. PCR was performed on DNA extracted from archived formalin-fixed, paraffin-embedded tissue blocks of skin from eight affected rowi, using primers targeting the 18S region of nuclear ribosomal DNA and the COI gene of mitochondrial DNA of capillarid nematodes. The 18S sequences from all rowi samples were identical and matched sequences from members of the genus Eucoleus. In contrast, two distinct capillarid COI sequences were obtained, in one case both from the same rowi skin biopsy. While there were no close matches, both COI sequences also aligned nearest to sequences identified as Eucoleus spp. It is considered unlikely that two different nematode species are involved in the rowi skin lesions and the possible amplification of a COI pseudogene or “numt” is discussed. A species-level identification of the capillarid nematodes causing skin disease in rowi was not obtained, however based on histological evaluation the infections include reproductively-active adult nematodes. This finding indicates the possibility of perpetuation of the skin disease in the absence of the original source, as well as raising potential for the transfer of infection from the island when the juvenile rowi are translocated to their new habitats.

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Dermatitis associated with nematode migration has been diagnosed in juvenile rowi kiwi.

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Histological and molecular analysis indicates a member of Capillaria sensu lato.

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The possible amplification of a COI pseudogene is discussed.

in the non-glandular stomach of wild urban rats (Rattus norvegicus)

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We used histology to examine wild rats for stomach pathology.

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Reactive lesions in the stomach of wild rats were associated with Eucoleus sp.

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Sexually mature and heavy rats had increased odds of infection.

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This represents a substantial host response to parasitism.

Histological lesions associated with Eucoleus sp. infection of the non-glandular stomach were discovered in a wild, urban population of Norway rats (Rattus norvegicus) trapped over a 1-year period in Vancouver, Canada. Four distinct categories of histological lesions in the non-glandular stomach were identified in association with infection in a sample of 183 rats. The apparent prevalence of Eucoleus sp. in the upper gastrointestinal tract (ventral tongue, oropharynx, esophagus and non-glandular stomach) was 43.1% (79/183). Infection with Eucoleus sp. was significantly associated with hyperkeratosis, mucosal hyperplasia, keratin pustules and submucosal inflammation in the non-glandular stomach (P < 0.05). Eucoleus sp. infection and/or related stomach pathology was present in 135/183 (73.8%) of rats. Statistical analysis showed the odds of being affected by Eucoleus sp. or associated stomach pathology were greater in heavier (OR = 1.06, 95% CI = 1.00–1.12) and sexually mature rats (OR = 4.64, 95% CI = 1.23–17.10). Eucoleus sp. infection is common in wild rats in Vancouver and induces substantial host response. The impact of Eucoleus sp. and associated lesions on the health of individual rats and the population as a whole remains to be investigated.