1. Investigación

Listeriosis is a zoonotic disease caused by Listeria monocytogenes and Listeria ivanovii. The genus Listeria currently includes 27 recognized species and is found throughout the environment. The number of systematic studies on antimicrobial resistance in L. monocytogenes isolates from domestic farms using antimicrobial substances is limited. Importantly, dairy ruminant farms are reservoir of hypervirulent lineage I L. monocytogenes isolates, previously associated with human clinical cases. Considering that the classes of antibiotics used in food-producing domestic animals are frequently the same or closely related to those used in human medicine, studies about the impact of antibiotic use on the acquisition of antibiotic resistance in Listeria spp. in domestic animal farms are, therefore, of high importance. Here, susceptibility to 25 antibiotics was determined. Eighty-one animal-related, 35 food and 21 human pathogenic Listeria spp. isolates and 114 animal-related non-pathogenic Listeria spp. isolates were tested. Whole genome sequencing data was used for molecular characterization. Regarding L. monocytogenes, 2 strains from the clinical-associated linage I showed resistance to erythromycin, both related to dairy ruminants. Acquired resistance to one antibiotic was exhibited in 1.5% of L. monocytogenes isolates compared with 14% of non-pathogenic Listeria spp. isolates. Resistance to tetracycline (7.9%), doxycycline (7.9%), penicillin (4.4%), and ampicillin (4.4%) were the most frequently observed in non-pathogenic Listeria spp. While resistance to two or more antibiotics (5.6%) was most common in Listeria spp., isolates, resistance to one antibiotic was also observed (1.6%). The present results show that non-pathogenic Listeria spp. harbour antimicrobial resistance genes.

Toxoplasmosis is one of the most common parasitic zoonoses and represents a significant health risk for humans, especially for immunodeficient patients. The main transmission route is by oral uptake of oocysts and consumption of undercooked meat of infected animals. Different species have been evaluated as possible reservoirs of the parasite, but few studies have been carried out to examine the role of horses in transmission of the disease. Given the proximity of these animals to humans and the widespread consumption of their meat in many countries, including the Mediterranean basin, it is important to determine the prevalence of T. gondii infection in this species. In this study, blood samples from 105 horses were collected and the presence of T. gondii was evaluated by serological and molecular methods. Antibodies against T. gondii of 12 horses (11.43%) were detected by enzyme-linked immunosorbent assay (ELISA), whereas 29 horses (27.62%) showed positive for PCR. Seroprevalence was related to use of the animals, being higher in horses used for dressage than in others. Purebreds had higher seroprevalence than crossbred animals. No differences between breed, sex or age were found. The results of this study confirm the presence of T. gondii infection in horses, highlighting the need to analyse the meat of this species before human consumption and to control of this infection in horses, as they could be an important reservoir of this zoonotic parasite.

Leishmaniosis is a zoonosis caused by Leishmania spp., an intracellular protozoan parasite. This parasite is transmitted by sandflies, and the disease is endemic in the Mediterranean basin. In recent years, the number of species which could be a reservoir of the parasite is increased. One of the most relevant species is the horse, due to their contact with humans and ability to control the disease, thus being a possible silent reservoir. In this study, we have analyzed the prevalence and factors related to L. infantum infection in healthy horses in the Mediterranean region. Epidemiological data and serum samples were obtained from 167 apparently healthy horses, and the presence of L. infantum was evaluated via the ELISA method and real-time PCR. The results show 27.5% of prevalence and that the main factors related to infection are equine breed, morphotype, outdoor living, use, and season. In conclusion, the prevalence of L. infantum infection in apparently healthy horses from eastern Spain (Mediterranean basin) is elevated. To control this zoonosis, it would be advisable to carry out more studies on this and other species that could be silent reservoirs of the parasite, as well as carry out measures such as the use of repellents on a regular basis.

Free-living cats usually live in colonies in urban areas, especially close to parks and neighbourhoods where people feed them without any sanitary control. This can pose a human, animal and environmental health concern due to the close contact between uncontrolled colonies, the population and other domestic and/or wild animals. Thus, this study aimed to assess the genetic diversity and antimicrobial resistance (AMR) among Salmonella enterica subsp. enterica strains isolated from feral cats in a previous epidemiological study in the Gran Canaria island (Spain). A total of nineteen Salmonella isolates were obtained from November 2018 to January 2019 in a Salmonella epidemiological study in feral cats. All isolates obtained were genotyped by pulsed-field gel electrophoresis (PGFE) and were tested for antimicrobial susceptibility, in accordance with Decision 2013/652/EU. PFGE analysis revealed isolates clustering by serovar, with identical clones for serovars Bredeney and Grancanaria, while differing pulsotypes were observed for serovars Florida (88.89 % similarity) and Nima (83.23 % similarity). All but two isolates were resistant to at least one antimicrobial. The results obtained demonstrate that feral cats in the region investigated are a reservoir of Salmonella strains resistant to gentamicin (94.1 %) and of the critically important antimicrobial tigecycline (23.5 %). Hence, they could excrete AMR strains through their faeces and contaminate the environment, favoring the spread of such bacteria to cohabiting pets. Moreover, this widespread presence of AMR Salmonella clones across various serovars highlights the urgent need to implement efficient antimicrobial stewardship and control programs by the local governments due to the ongoing need to protect human and animal health under a One Health concept.

Dogs are considered the main reservoir of several zoonoses endemic to the Mediterranean Basin. In this study, a prevalence of infections and coinfections of canine vector-borne diseases was analyzed in apparently healthy dogs of different canine pure breeds in Sicily (Italy), where these diseases are endemic. The seroprevalence of Leishmania infantum, Ricketsia ricketsii, Anaplasma phagocytophilum, and Erlichia canis was assessed, as single and coinfections. Biochemical and hematological parameters were evaluated, and epidemiological factors, including sex, age, and canine breed, were recovered. The most frequent infection was L. infantum (45.61%), following R. ricketsii (36.84%), both as single, double, or triple coinfections. Coinfections change the biochemical and hematological parameters of the host, and canine breeds are related to the infection frequency and the parameters observed during infections. Changes in the complete blood count (CBC) and biochemical values also differ between canine breeds, with the Cirneco dell’Etna dogs infected with L. infantum being the animals presenting the most interesting results in our study. High values of RBC, hemoglobin, hematocrit, mean corpuscular hemoglobin (MCH), the albumin/globulin (A/G) ratio, and albumin and low levels of β-2 globulin and γ-globulin were found only in this canine breed, suggesting some resistance to infection in these dogs. Future studies about the immune response of this canine breed could be interesting to determine their possible resistance to zoonotic pathogens, such as L. infantum.

Leishmaniasis and toxoplasmosis are two of the most common parasitic zoonoses. Leishmaniasis is endemic to 98 countries around the world, whereas toxoplasmosis is widely distributed throughout the world, causing significant health expenditure. Horses can play a relevant role in the transmission of the disease, being a silent reservoir, as clinical signs are not common. Serum samples from 166 horses living in eastern Spain (Mediterranean basin) were analysed to determine the presence of antibodies against Leishmania spp. and T. gondii by ELISA (Enzyme-linked Immunosorbent Assay.) The risk factors evaluated were the geographical area and the relative humidity and average temperature, and epidemiological factors such as sex, reproductive status, age, breed, morphotype, living with other domestic animals, use and access to the outdoors. Seroprevalence of Leishmania spp. and T. gondii infection was found 28.92%, and 16.27% respectively, whereas co-infection of the two parasites was found only in two males. Leishmania seroprevalence was high in castrated males and several mesodolichomorphic equine breeds used for teaching, as well as in outdoor animals. The most elevated seroprevalence was found in winter with higher levels of rainfall, whereas high seroprevalence of T. gondii was found in crossbreeding animals and those used for breeding. High seroprevalence of Leishmania spp. and T. gondii was found in horses of the Mediterranean basin. These data suggest that horses can act as a silent reservoir and that this species has high potential for transmission to humans, outdoor animals and in geographical areas with high average rainfall.

In Guatemala, three million people are at risk of contracting cutaneous leishmaniosis, primarily in the northern regions. Despite this alarming epidemiological situation, few faunistic studies of phlebotomine sand flies have been conducted in this country, which is the most populous in Central America. An entomological survey of phlebotomine sand flies was carried out from March to September, 2018 in rural, mountainous, and forested areas of six northern Guatemalan departments with active transmission of human leishmaniosis: Petén, Huehuetenango, Quiché, Alta Verapaz, Izabal, and El Progreso. CDC miniature light traps were deployed in and around homes with recent cases of leishmaniosis in children under 10 years of age. A total of 2,605 specimens of sand flies were captured and identified, belonging to three subtribes, nine genera, and 14 species (13 of which were able to be determined), with a balanced sex ratio of 0.95 males per each female. Lutzomyia longipalpis was the most abundant species in the survey, accounting for 62.61% of the total catches; however, this species was restricted to El Progreso and Huehuetenango, with Huehuetenango having the highest capture percentage (55.54%). This vector was predominantly found outdoors, mostly in extra-domicile areas (62.29%). The male/female ratio for this species was 1.94. This study, and the entomological data we present, can aid in enhancing vector control interventions in these northern departments, thereby decreasing the incidence of leishmaniosis in humans.

Nematocera are a suborder of Diptera which historically influenced human history more than any other arthropod group. Four families show a hematophagous behaviour, one being solenophagous (Culicidae), feeding directly on blood vessels, and three being telmophagous (Ceratopogonidae, Psychodidae, and Simuliidae), feeding on blood which pools at the site where their mouthparts have formed a laceration. Although mosquitoes rank first in importance, the telmophagous are also of great interest. Objectives: to update the status of these nematocerans through a transdisciplinary approach, reviewing the main characteristics of each family, the situation of the main vector-borne diseases transmitted by them in the country, especially during the 21st century, and the most relevant species or species groups from a medical and veterinary perspective. Methods: a literature search of databases was conducted and supplemented by browsing specialized journals and citation searching. Results were reviewed and filtered. Results: to date, 84 species of biting midges (Ceratopogonidae), 13 species of sand flies (Psychodidae), and 53 species of black flies (Simuliidae) have been reported in Spain. Culicoides imicola and the Obsoletus complex stand out as the most important biting midges, as they are incriminated in the transmission of bluetongue and Schmallemberg virus; Phlebotomus perniciosus and Phlebotomus ariasi are the vectors of Leishmania infantum; and Simulium erythrocephalum and the Ornatum complex cause the greater part of nuisance and bites to humans in Spain. Conclusions: there is a need to increase research capacity in Spain in order to address several health challenges arising from the presence of telmophagous Nematocera in particular, and of blood-sucking atropods in general.

Leishmaniosis is considered the most important neglected tropical disease caused by protozoan parasites in Southern European countries such as Spain. Its main etiological agent is Leishmania infantum while Phlebotomus perniciosus and Phlebotomus ariasi are the main vectors in the country. During the first half of July 2021, an entomological survey was conducted in a dog shelter and its surroundings in the municipality of Toledo (Castilla-La Mancha). Sand fly sticky traps, made of A5-size white paper coated with castor oil, were placed in six different environments inside a 200 m (the mean flight distance of Phlebotomus sp.) radius from the animal shelter. Sticky traps were set for eleven consecutive trapping nights in each site. A total of 356 phlebotomine sand flies belonging to four species in two genera were identified. These species and their abundance in the traps were: Sergentomyia minuta (70.2%), Phlebotomus perniciosus (25.9%), Phlebotomus sergenti (2.8%), and Phlebotomus papatasi (1.1%). The following list gives a breakdown of the abundance of phlebotomine sand flies found in various locations: a burrow (45.1%), a maintenance warehouse (21.3%), a holm oak´s tree hole (15.6%), an abandoned cattle barnyard (10.3%), a dog kennels area (4.3%), and surroundings of a feral feline colony (3.3%). Phlebotomus papatasi, an anthropophagic species, was only found in crevices of the maintenance warehouse. Although dogs are considered the main Leishmania reservoir, this preliminary research shows the effect of different micro-environments in the surroundings of animal shelters on sand fly abundance and diversity, and the importance that other reservoirs could play as most documented captures were associated with glires (orders Rodentia and Lagomorpha) rather than dogs and cats.