Occurrence, prevalence, and explanatory environmental variables of Spirocerca vulpis infestation in the foxes of western Spain.

The main aim of this study was to not only establish the prevalence of the recently described Spirocerca vulpis parasite in the wild-life cycle of carnivores in western Spain but to also elaborate a model to explain the risk of infestation based on 16 topo-climatic and habitat variables. During the period from June 2016 to November 2017, 1644 carcasses of red foxes (Vulpes vulpes) and another 105 wild mammals, legally hunted or killed in car accidents, were analyzed. Parasitic nodules of Spirocerca were found in 6% of the foxes, and the molecular analyses established a homology of our samples with the species S. vulpis. There were no differences in the occurrence of the infestation between sexes, but there were differences in terms of age, such that infestation was proportionally more frequent among young individuals. In terms of temporality, a higher percentage of positive cases was observed during the late-autumn and winter months, especially between December and February. This study provides new data on the factors that predispose S. vulpis infection in the red fox. Model results indicate that a spatial pattern exists in the occurrence and prevalence of this species in the studied area (higher probabilities to the west), and that this pattern seems to mainly be associated with topo-climatic variables.

Rare but evolutionarily consequential outcrossing in a highly inbred zoonotic parasite.

Recurrent self-mating can result in nearly clonal propagation of biological lineages, but even occasional outcrossing can serve to redistribute variation in future generations, providing cohesion among regional populations. The zoonotic parasite Trichinella spiralis has been suspected to undergo frequent inbreeding, resulting in genetically uniform larval cohorts which differ markedly from one another. Here, we explored the extent of inbreeding for this parasite by determining how genetic variation (at variable microsatellite markers) is distributed among 1379 larvae derived from 41 wild boars in Extremadura, Spain. In particular, we sought to determine how much of the genetic variation in this region's parasites occurs among the larvae of any given wild boar, and whether each derives from one, or more, parental lineages. We found strong evidence for inbreeding, resulting in genetically distinct parasite subpopulations among the parasites derived from many pairs of wild boar. Fully two-thirds of these parasite cohorts appear to derive from inbred parents; in 10% of the wild boars, parasites were so inbred as to become absolutely fixed in all of the assayed genetic loci. In spite of this, more than one pair of parents appear to have given rise to the infections in one-third of the sampled wild boars, resulting in mixed infections. These mixed infections should slow losses of heterozygosity and multi-locus polymorphism in any given parasite lineage. Such outcrossing should limit distinctions that would otherwise accumulate among transmission chains, thereby enforcing cohesion through the region's population in spite of its marked departure from panmixia. Conditions of transmission may differ in other regions, where such epidemiological features may engender different evolutionary outcomes.

Detection of Leishmania DNA and blood meal sources in phlebotomine sand flies (Diptera: Psychodidae) in western of Spain: Update on distribution and risk factors associated.

Leishmaniosis caused by Leishmania infantum is present in Mediterranean countries, with high prevalence in areas of the center and south of Spain. However, in some regions such as Extremadura (in southwest of Spain), data has not been updated since 1997. The aim of this work was (i) to provide information about the distribution of phlebotomine sand fly species in western of Spain (Extremadura region), (ii) to determine risk factors for the presence of sand fly vectors and (iii) to detect Leishmania DNA and identify blood meal sources in wild caught females. During 2012-2013, sand flies were surveyed using CDC miniature light-traps in 13 of 20 counties in Extremadura. Specimens were identified morphologically and females were used for molecular detection of Leishmania DNA by kDNA, ITS-1 and cyt-B. In addition, blood meals origins were analyzed by a PCR based in vertebrate cyt b gene. A total of 1083 sand flies of both gender were captured and identified. Five species were collected, Phlebotomus perniciosus (60.76%), Sergentomyia minuta (29.92%), P. ariasi (7.11%), P. papatasi (1.48%) and P. sergenti (0.74%). The last three species constitute the first report in Badajoz, the most southern province of Extremadura region. Leishmania DNA was detected in three out of 435 females (one P. pernicious and two S. minuta). Characterization of obtained DNA sequences by phylogenetic analyses revealed close relatedness with Leishmania tarentolae in S. minuta and L. infantum in P. perniciosus. Haematic preferences showed a wide range of hosts, namely: swine, humans, sheep, rabbits, horses, donkeys and turkeys. The simultaneous presence of P. perniciosus and P. ariasi vectors, the analysis of blood meals, together with the detection of L. infantum and in S. minuta of L. tarentolae, confirms the ideal conditions for the transmission of this parasitosis in the western of Spain. These results improve the epidemiological knowledge of leishmaniosis and its vectors in this part of Spain, highlighting the need for ongoing entomological and parasitological surveillance.

Detection of Zoonotic Protozoa Toxoplasma gondii and Sarcocystis suihominis in Wild Boars from Spain.

Food safety regulations require the control of the presence of protozoa in meats destined for human consumption. Wild boar (Sus scrofa) meat may constitute a source of zoonoses. A 23.8% (688/2881) seroprevalence of anti-Toxoplasma gondii antibodies and 72.2% (662/910) Sarcocystis sarcocysts prevalence were detected among wild boars hunted in Southwestern areas of Spain. Identity of Sarcocystis spp. was performed by RFLP-PCR and sequencing, detecting S. miescheriana (7/8) and the zoonotic S. suihominis (1/8). Risk assessment studies of these coccidian in meats destined to human consumption are needed.

Histopathology of trichinellosis in wild boar.

Histopathological study of Trichinella constitutes an important knowledge base to understand the pathogenesis of this disease. This study analyses cell response and macroscopic lesions in wild boar for the two species of Trichinella present in Spain: Trichinella spiralis and T. britovi. We carried out both trichinelloscopy and artificial digestion to calculate the parasitic load and relate this to the macroscopic lesions. The results obtained prove a lesser adaptation of T. britovi in wild boar. From a histological point of view, the organic region that was most affected was the skeletal muscle, where inflammatory infiltrates were observed around the larvae, and they were most abundant in calcified cysts.

Comparison of IgM, IgG1 and IgG2 responses to Trichinella spiralis and Trichinella britovi in swine.

Pigs infected with T. spiralis and T. britovi were followed by double (IgG) and triple antibody ELISA (IgG1, IgG2 and IgM) during a 12-week-period. Specific IgG and IgG1 responses were similar and showed a significant relation with the infecting doses and intensity of infection. Response to T. britovi was slightly lower than in groups infected with the same dose of T. spiralis. IgG2 response was weak and almost undetectable in the lowest infected pigs, but relationship with the intensity of infection was unclear. IgM antibodies showed rapid but transient increases, generally simultaneous to peaks of IgG response.

Sylvatic trichinellosis in southwestern Spain.

The epidemiology of Trichinella spp. in their main sylvatic hosts, wild boar (Sus scrofa ferus and red fox (Vulpes vulpes), in Extremadura (southwestern Spain) was studied. We examined 88 Trichinella spp.-positive wild boar muscle-tissue samples from a total of 29,333 killed animals, referred to the Veterinary Parasitology Department (University of Extremadura, Spain) by the Extremadura Veterinary Service. Additionally, 227 red foxes killed during the hunting season and thus not subject to veterinary controls were examined for trichinellosis. Trichinella spp. larvae were found in six (3%) of the red foxes. All samples were examined using direct diagnostic techniques, including trichinoscopy and artificial digestion. The mean intensity of infection was 74.8 larvae/g (LPG) of muscle tissue in wild boars, compared to 30.6 LPG in foxes. Trichinella spiralis (sensu stricto) predominated over T. britovi in wild boars. Random amplified polymorphic DNA (RAPD) and alloenzyme typing showed that 74% of infected wild boars had only T. spiralis, 21% had only T. britovi, and 5% showed mixed infections. In contrast, 33% of infected foxes were infected only with T. spiralis, while 67% had T. britovi, suggesting a clear predominance of the latter in foxes. We suspect the existence of a paranthropic or sylvatic cycle in large areas of this region; given the ease of transfer between sylvatic and domestic or semi-domestic animals, this implies a high epidemiological risk.

Influence of infection intensity on predilection sites in swine trichinellosis.

The muscular distribution of Trichinella spiralis or T. britovi was studied by digestion in 59 experimentally infected pigs and seven wild boars. Crus muscle was the predilection site in 89.3% of 28 heavily infected swine with 146-3634 larvae per gram (lpg), but in 51.6% of middle to light infections (0.005-59 lpg) the basis of the tongue showed higher larval densities than the crus muscle. The basis of the tongue was also the predilection site in 71.4% of wild boars. Highest counts in other muscles were found only in lightly infected pigs. The influence of intensity of infection, host species, and Trichinella species on muscle distribution is discussed.