C. Martínez-Carrasco

Epidemiological study of non-systemic parasitism in dogs in Southeast Mediterranean Spain assessed by coprological and post-mortem examination.

The prevalence and risk factors of non‐systemic canine ecto‐ and endoparasitism and anthelminthic use in Murcia located at the centre of the Spanish Mediterranean coastal arch, was investigated by coprology and necropsy in up to 275 pet, city shelter and stray dogs in 2001–2004. Faecal parasite stages were detected in 25% of dogs. Species frequency was 6–10% for Toxocara canis, Ancylostomatidae spp., Toxascaris leonina and Isospora canis, and 0.4–1% for Trichuris vulpis, Giardia lamblia, and Dipylidium caninum. Logistic regression indicated that the risk of intestinal parasitism was highest for dogs ≤1 year old, in the middle to low weight range and kept at the city shelter. Although risk factors varied according to the species, T. canis was most common in <1 year old and Ancylostomatidae spp. was more prevalent in older dogs. This suggests that the dominant species was Uncinaria spp. and not the more zoonotically important Ancylostoma spp. This was further supported by necropsy findings; however, the degree of agreement between post‐mortem and coprological examination for intestinal parasites was generally poor. Necropsy revealed 10%G. lamblia, 12%Taenia spp. 38%D. caninum infections. Fleas, ticks and lice were also found in 38%, 6% and 2% of necropsied stray dogs. These results demonstrate the need for an urgent parasite control programme at the city dog shelter and the need to improve the owner’s education on zoonotic risks, the proper use of anthelminthics, and other parasite control practices.

Seropathotypes, Phylogroups, Stx Subtypes, and Intimin Types of Wildlife-Carried, Shiga Toxin-Producing Escherichia coli Strains with the Same Characteristics as Human-Pathogenic Isolates

ABSTRACT The objectives of this study were to investigate the presence of Shiga toxin-producing Escherichia coli (STEC) strains in wildlife that have spread in Europe, living near human settlements; to analyze their epidemiological role in maintenance and transmission to domestic livestock; and to assess the potential health risk of wildlife-carried strains. STEC strains were recovered from 53% of roe deer, 8.4% of wild boars, and 1.9% of foxes sampled in the northwest of Spain (Galicia). Of the 40 serotypes identified, 21 were classified as seropathotypes associated with human disease, accounting for 81.5% of the wildlife-carried STEC strains, including the enterohemorrhagic serotypes O157:H7-D-eae-γ1, O26:[H11]-B1-eae-β1, O121:H19-B1-eae-ε1, and O145:[H28]-D-eae-γ1. None of the wildlife-carried strains belonged to the highly pathogenic serotype O104:H4-B1 from the recent Germany outbreak. Forty percent of wildlife-carried STEC strains shared serotypes, phylogroups, intimin types, and Stx profiles with isolates from human patients from the same geographic area. Furthermore, wildlife-carried strains belonging to serotypes O5:HNM-A, O26:[H11]-B1, O76:H19-B1, O145:[H28]-D, O146:H21-B1, and O157:H7-D showed pulsed-field gel electrophoresis (PFGE) profiles with >85% similarity to human-pathogenic STEC strains. We also found a high level of similarity among STEC strains of serotypes O5:HNM-A, O26:[H11]-B1, and O145:HNM-D of bovine (feces and beef) and wildlife origins. Interestingly, O146:H21-B1, the second most frequently detected serotype in this study, is commonly associated with human diarrhea and isolated from beef and vegetables sold in Galicia. Importantly, at least 3 STEC isolates from foxes (O5:HNM-A-eae-β1, O98:[H21]-B1-eae-ζ1, and O146:[H21]-B1) showed characteristics similar to those of human STEC strains. In conclusion, roe deer, wild boar, and fox in Galicia are confirmed to be carriers of STEC strains potentially pathogenic for humans and seem to play an important role in the maintenance of STEC.

Post-entry blockade of small ruminant lentiviruses by wild ruminants

Small ruminant lentivirus (SRLV) infection causes losses in the small ruminant industry due to reduced animal production and increased replacement rates. Infection of wild ruminants in close contact with infected domestic animals has been proposed to play a role in SRLV epidemiology, but studies are limited and mostly involve hybrids between wild and domestic animals. In this study, SRLV seropositive red deer, roe deer and mouflon were detected through modified ELISA tests, but virus was not successfully amplified using a set of different PCRs. Apparent restriction of SRLV infection in cervids was not related to the presence of neutralizing antibodies. In vitro cultured skin fibroblastic cells from red deer and fallow deer were permissive to the SRLV entry and integration, but produced low quantities of virus. SRLV got rapidly adapted in vitro to blood-derived macrophages and skin fibroblastic cells from red deer but not from fallow deer. Thus, although direct detection of virus was not successfully achieved in vivo, these findings show the potential susceptibility of wild ruminants to SRLV infection in the case of red deer and, on the other hand, an in vivo SRLV restriction in fallow deer. Altogether these results may highlight the importance of surveilling and controlling SRLV infection in domestic as well as in wild ruminants sharing pasture areas, and may provide new natural tools to control SRLV spread in sheep and goats.

Questionnaire survey on Canine Leishmaniosis in southeastern Spain

A veterinary practitioners questionnaire survey on Canine Leishmaniosis (CanL) was carried out in southeast Spain to provide information on disease incidence, diagnosis and recommended preventive measures. A third of 101 responding veterinarians reported seeing more than 20 CanL cases during the previous year and clinical signs considered frequent or very frequent included weight loss, areas of exfoliative dermatitis, lymphadenomegaly, kidney dysfunction, onychogryphosis, cutaneous ulcers, anaemia, asthenia and apathy. Almost a third of veterinarians reported diagnosing CanL solely on the basis of lack of response to treatment for other chronic illnesses. The frequency of individual signs did not always reflect their diagnostic value. The majority of veterinarians, considered lymphadenomegaly, exfoliative dermatitis, onychogryphosis, weight loss and epistaxis to be the best disease indicators. However, up to 93% of veterinarians reported using laboratory tests to confirm infection, including indirect (biochemical and antibody assays) and direct (PCR and microscopy) methods. Among recommended measures to prevent CanL, insecticide impregnated collars and topical spot-on capsules were prescribed by 92% and 74% of respondents; however, at least 11% of veterinarians believed existing CanL preventive measures were ineffective. Multivariable statistical analysis indicated that seeing more than 20 CanL cases during the previous year was independently associated with being located in Alicante province, having a rural clientele and recognising that dogs with no other sign but a lack of response to other chronic disease treatments may be infected with CanL. There was a weak association between CanL incidence and rainfall in the months prior to typical sandfly peak abundance.

Coinfection is an important factor in epidemiological studies: the first serosurvey of the aoudad (Ammotragus lervia).

Despite being considered an invasive ungulate outside its native range (North Africa), little information exists regarding the role of the aoudad (also called Barbary sheep, Ammotragus lervia) as a pathogen reservoir. Furthermore, in most epidemiological surveys the potential role of coinfections (e.g. a first infection may make the host more immuno-competent or susceptible against a second pathogen) as a risk factor is often neglected. In this study we first performed a serological survey for selected pathogens (Mycobacterium bovis, M. avium subsp. paratuberculosis, Chlamydophila abortus, bovine viral diarrhoea/border disease viruses (BVDV-BDV), Salmonella spp., Brucella melitensis and Toxoplasma gondii) on free (n = 66) and captive (n = 25) aoudad from south-east Spain. Then, by using Akaike’s information criterion, we evaluated the importance of coinfection in two statistical models that included the effects of population, age, and sex. Our results show that neither free nor captive aoudad had antibodies against Brucella melitensis, Chlamydophila abortus, or BVDV-BDV. However, compared to other wild ungulates in Spain, aoudads have high prevalence of antibodies against M. bovis (free = 49.5%; captive = 8%), very high prevalence of antibodies against M. avium subsp. paratuberculosis (free = 19.4%; captive = 56%), and intermediate prevalence of antibodies against Salmonella spp. (free = 13.4%; captive = 0%) or T. gondii (free = 1.5%; captive = 24%). Although the additive effects of population and age were included in our set of selected models, coinfection was the most influential factor to detect antibodies response against mycobacterials and salmonella infections. The direction of this influence could be exclusion of disease between tuberculosis and paratuberculosis seroreactor animals, or enhanced susceptibility to disease between tuberculosis and salmonella seroreactor animals. In conclusion, we believe that wildlife managers must pay more attention to the potential risk posed by aoudads as hosts (and probably reservoirs) of paratuberculosis and tuberculosis mycobacterials, while epidemiologists should be more aware of coinfection as an important factor in epidemiological surveys, especially in wildlife populations where multiple infections are common.

Variable performance of a human derived Sarcoptes scabiei recombinant antigen ELISA in swine mange diagnosis

The performance of an indirect ELISA test based on Sarcoptes scabiei var hominis recombinant antigen Ssλ20ΔB3 (rec-ELISA), to diagnose pig mange was investigated in 15 experimentally infected and non-infected pigs and 692 commercial pigs from 16 herds in southeast Spain. These latter animals included 6-7 month old fatteners (13 herds), 11-12 month old replacement sows (1 herd) and ≥24 month old breeding sows (7 herds). All pigs were examined for mites in ear skin scrapings and the presence of S. scabiei-associated macroscopic dermatitis; moreover, fatteners were also tested for antibodies against porcine viruses including: Aujeszky disease virus (ADV), swine influenza virus (SIV), type 2 porcine circovirus (PCV2) and porcine respiratory and reproductive syndrome virus (PRRSV). S. scabiei and chronic hyperkeratotic dermatitis were detected in breeding sows from 6 herds. Mite prevalence in other pigs was 83% in replacement sows, 0% in 7 fatteners herds and 3-82% in other fatteners herds. All fattener herds had pigs with acute hypersensitivity dermatitis and the percentage of affected pigs and lesion area was significantly greater in S. scabiei infected ones. Rec-ELISA relative optical densities (RODs) were greater in older than in young pigs, as well as in infected compared to non-infected pigs. However, RODs differed significantly between infected individuals, regardless of age and origin (commercial or experimental) and the herd prevalence of S. scabiei. Low repeatability between ELISA microtiter plates, suggesting variable specific antibody binding to antigen, are likely partly responsible for ROD variation. Other potential causes of variation were examined in fatteners using random effects logistic regression analysis, after defining a seropositivity threshold value with receiver-operating characteristics (ROC) analysis. The logistic model indicated that seropositivity was associated with large dermatitis areas and with the only herd with low PCV2 seroprevalence. Pigs with more extensive dermatitis may have older infections and more rec-ELISA detectable antibodies. The possibility that PCV2, a recognized immunosupressor, depresses antibody production against S. scabiei infection merits further attention. In summary, results indicate some potential of the studied rec-ELISA as a complementary tool for herd-level swine mange diagnosis, and that work to reduce internal and external sources of assay variation is essential.

DETECTION OF ANTIBODIES IN WILD RUMINANTS TO EVALUATE EXPOSURE TO LIVER TREMATODES

Abstract: Wild ruminants sharing pastures with domestic livestock are at risk of infection by liver trematodes. Detection of antibodies provides a very useful tool to gain more knowledge about the distribution of these parasites. Non-lethal methods are strongly encouraged for the analysis of the risk of infection among wild ruminants. A seroepidemiological survey was conducted to analyze exposure to hepatic trematodes (Fasciola hepatica and Dicrocoelium dendriticum) in wild ruminants from southern Spain. Blood samples were collected from 69 bovids (Mouflon + Spanish ibex) and 143 cervids (red deer + fallow deer) from Sierra de Cazorla, Segura and Las Villas Natural Park. The samples were analyzed using the excretory/secretory antigens of each trematode to determine the IgG response. All the animals were examined at necropsy for the presence of flukes, and the species, age, and gender of the animals were recorded. Fasciola hepatica were only observed in cervids (3%; 95% confidence interval [CI]  =  2–8), while D. dendriticum specimens were recorded in 1% (0–8) of bovids and 4% (CI  =  2–9) of the cervids. The IgG-seroprevalence against F. hepatica was significantly higher in the cervids. Statistical differences according to gender were observed. The bovids exhibited the greatest percentages of positive cases to D. dendriticum antigens, and the DdES-seroprevalence was related to age of the animals. When considering all the factors, the FhES-seroprevalence was initially distributed according to the type of ruminant (cervids), gender (male), and age (>2 yr).

On the aggregated nature of chronic Sarcoptes scabiei infection in adult pigs.

The prevalence and body distribution of Sarcoptes scabiei and associated dermatitis was investigated in sows and boars from four herds with long standing mange. Macroscopic hyperkeratotic dermatitis (crusted mange) was present in 1-6% of herd sows. Mite estimated prevalence (95% CI) in ear scrapings was 11% (6-17%) including 100% (13/13) and 2% (3/134) in sows with and without crusted mange, respectively, and the later had very few mites compared to the former. S. scabiei body distribution and dermatitis were further investigated in 59-64 skin scrapings/sow taken post-mortem from four culled sows including two (sows 1 and 2) with and two (sows 3 and 4) without crusted mange. The proportion of skin samples with eggs, instars or adults was 59% in sow 1, 84% in sow 2, 0% in sow 3 and 3% in sow 4. S. scabiei distribution in sows 1 and 2 ranged from being present in all skin ear and head samples to absent in those from the inner side of the limbs and mammary glands. Crusted lesions were observed in the skin of the ears, neck and lower limbs and contained the largest mite populations. Histopathological analysis of skin samples identified mites, inflammatory cellular infiltrate (mainly lymphocytes, neutrophils and eosinophils) and hyperkeratosis, acanthosis and spongiosis in 78%, 54%, 20% and 25% of samples from sows 1, 2, 3 and 4, respectively, being lesion severity positively associated to mite presence. The study provides further evidence that in herds with long-standing exposure to S. scabiei, infection becomes highly overdispersed with large mite populations present only in a few pigs and in specific body areas. Although the reasons for mite aggregation have not been identified, it is important controlwise because treating or eliminating a few and easy to identify heavily infected adult pigs, should markedly decrease the herds parasite load and reduce the use of acaridal drugs.

Use of a crude extract or purified antigen from first‐instar cattle grubs, Hypoderma lineatum, for the detection of anti‐Hypoderma antibodies in free‐ranging cervids from southern Spain

During the 2003–2005 hunting seasons, a total of 120 Cervidae, including 39 red deer (Cervus elaphus hispanicus) and 81 fallow deer (Dama dama), were examined for subcutaneous myiasis. Animals were shot from January to June in southern Spain. Specific antibodies against Hypodermatinae (Diptera: Oestridae) were detected by indirect enzyme‐linked immunosorbent assay (iELISA) using a crude larval extract (CLE) and a purified antigen [hypodermin C (HC)] obtained from first instars of Hypoderma lineatum (De Villers) (Diptera: Oestridae). Hypoderma actaeon Brauer was the only species detected in this study, which represents the first confirmation of this species in fallow deer from Spain. The overall prevalence of animals presenting subcutaneous larvae (14.2%) was considerably lower than the prevalences determined by iELISA with CLE (43.3%) and HC (40.0%). Red deer showed a higher prevalence of Hypoderma than fallow deer. The concordance between larval examination during the hunting season and iELISA using both antigens was low, whereas the concordance between the CLE and HC ELISAs was good. Larval antigens obtained from H. lineatum constitute a good tool for the diagnosis of H. actaeon in Cervidae, especially when the hunting season does not coincide with the maximum presence of larvae on the back.

Carnivore carcasses are avoided by carnivores

Ecologists have traditionally focused on herbivore carcasses as study models in scavenging research. However, some observations of scavengers avoiding feeding on carnivore carrion suggest that different types of carrion may lead to differential pressures. Untested assumptions about carrion produced at different trophic levels could therefore lead ecologists to overlook important evolutionary processes and their ecological consequences. Our general goal was to investigate the use of mammalian carnivore carrion by vertebrate scavengers. In particular, we aimed to test the hypothesis that carnivore carcasses are avoided by other carnivores, especially at the intraspecific level, most likely to reduce exposure to parasitism. We take a three-pronged approach to study this principle by: (i) providing data from field experiments, (ii) carrying out evolutionary simulations of carnivore scavenging strategies under risks of parasitic infection, and (iii) conducting a literature-review to test two predictions regarding parasite life-history strategies. First, our field experiments showed that the mean number of species observed feeding at carcasses and the percentage of consumed carrion biomass were substantially higher at herbivore carcasses than at carnivore carcasses. This occurred even though the number of scavenger species visiting carcasses and the time needed by scavengers to detect carcasses were similar between both types of carcasses. In addition, we did not observe cannibalism. Second, our evolutionary simulations demonstrated that a risk of parasite transmission leads to the evolution of scavengers with generally low cannibalistic tendencies, and that the emergence of cannibalism-avoidance behaviour depends strongly on assumptions about parasite-based mortality rates. Third, our literature review indicated that parasite species potentially able to follow a carnivore-carnivore indirect cycle, as well as those transmitted via meat consumption, are rare in our study system. Our findings support the existence of a novel coevolutionary relation between carnivores and their parasites, and suggest that carnivore and herbivore carcasses play very different roles in food webs and ecosystems.