First survey on canine leishmaniasis in a non classical area of the disease in Spain (Lleida, Catalonia) based on a veterinary questionnaire and a cross-sectional study

Sand fly-borne diseases in Europe: epidemiological overview and potential triggers for their emergence and re-emergence

Phlebotomine sand flies (Diptera: Phlebotominae) are vectors of human and animal pathogens, including Leishmania species protozoan parasites and viruses of the genus Phlebovirus. In Europe, visceral zoonotic leishmaniasis caused by Leishmania infantum, a deadly disease when left untreated, is endemic in southern countries, and dogs are the main reservoir hosts for human infection. Most phleboviruses cause asymptomatic infections or flu-like syndromes in humans, but Toscana phlebovirus can cause meningitis and encephalitis. These diseases are likely to re-emerge, posing a growing threat to public and animal health. Potential triggers include the movement of humans and dogs, increasing numbers of immunosuppressive conditions, climate change and other human-mediated environmental changes. An overview of the main epidemiological characteristics of the pathogens transmitted by sand flies in Europe and the potential triggers involved in their emergence and re-emergence are reviewed here. There is a need to implement mandatory notification of human and canine leishmaniases and human phleboviruses and coordinated epidemiological surveillance programmes at a European level, and to raise awareness among healthcare professionals and citizens about sand fly-borne diseases, following a One Health approach.

Social media as a tool for detecting underdiagnosed parasitic infections: the case of spirocercosis

Spirocercosis is a parasitic disease caused by the nematode Spirocerca lupi that affects several canids around the world. In Costa Rica, few spirocercosis cases have been reported; however, it is suspected that the infection is currently underdiagnosed. As seen during the COVID-19 pandemic, social media has sped up the spread of scientific knowledge, raising practioner's awareness of the epidemiology and signs and manifestations of infections. The aim of this work was to use social media as a tool for increasing awareness of spirocercosis among veterinarians and investigate the frequency of cases occurring in Costa Rica. Infographic material about the infection was disseminated by Whatsapp, Facebook, and Instagram from January 2021 to July 2022 using a public account of the Laboratory of Helminthology of the University of Costa Rica. In addition, Google Forms questionnaires were completed by veterinarians to report the number of spirocercosis cases in their clinics, associated manifestations, diagnosis, treatment, and outcome of the disease. Remarkably, since 2020, a six-fold increase in the number of cases per year was noted. Clinical manifestations matched those reported elsewhere, and one of every three dogs infected with S. lupi died spontaneously or required euthanasia because of the infection. This work suggests that S. lupi infection in Costa Rica may have been underdiagnosed in the last decade, and the knowledge and awareness of clinical personnel play a major role in the detection of this and other infectious diseases.

The estimated distribution of autochthonous leishmaniasis by Leishmania infantum in Europe in 2005-2020

BACKGROUND

This study describes the spatial and temporal distribution between 2005 and 2020 of human and animal leishmaniasis by Leishmania infantum in European countries reporting autochthonous cases, and highlights potential activities to improve disease control.

METHODOLOGY/PRINCIPAL FINDINGS

It was based on a review of the scientific literature and data reported by the World Health Organization (WHO), the World Organization for Animal Health (WOAH) and the Ministries of Health, including hospital discharges in some countries. Autochthonous infections were reported in the scientific literature from 22 countries, including 13 and 21 countries reporting human and animal infections, respectively. In contrast, only 17 countries reported autochthonous human leishmaniasis cases to the WHO and 8 countries animal infections to the WOAH. The number of WOAH reported cases were 4,203, comprising 4,183 canine cases and 20 cases in wildlife. Of 8,367 WHO reported human cases, 69% were visceral leishmaniasis cases-of which 94% were autochthonous-and 31% cutaneous leishmaniasis cases-of which 53% were imported and mostly in France. The resulting cumulative incidence per 100,000 population of visceral leishmaniasis between 2005-2020, was highest in Albania (2.15 cases), followed by Montenegro, Malta, Greece, Spain and North Macedonia (0.53-0.42), Italy (0.16), Portugal (0.09) and lower in other endemic countries (0.07-0.002). However, according to hospital discharges, the estimated human leishmaniasis incidence was 0.70 in Italy and visceral leishmaniasis incidences were 0.67 in Spain and 0.41 in Portugal.

CONCLUSIONS/SIGNIFICANCE

Overall, there was no evidence of widespread increased incidence of autochthonous human leishmaniasis by L. infantum in European countries. Visceral leishmaniasis incidence followed a decreasing trend in Albania, Italy and Portugal, and peaked in Greece in 2013, 2014 and 2017, and in Spain in 2006-2007 and 2011-2013. Animal and human cutaneous leishmaniasis remain highly underreported. In humans, hospital discharge databases provide the most accurate information on visceral leishmaniasis and may be a valuable indirect source of information to identify hotspots of animal leishmaniasis. Integrated leishmaniasis surveillance and reporting following the One Health approach, needs to be enhanced in order to improve disease control.

Seropositivity of main vector-borne pathogens in dogs across Europe

BACKGROUND

Canine vector-borne disease (CVBD) has been an area of increasing interest in Europe over the last few decades, and there have been changes in the prevalence and distribution of many of these diseases. Monitoring CVBD infections in Europe is often done by individual countries, but aggregated data for the European countries are helpful to understand the distribution of CVBDs.

METHODS

We used an extensive retrospective database of results from point-of-care rapid enzyme-linked immunosorbent assay (ELISA) tests on dogs across Europe to identify distribution and seropositivity in animals tested for selected CVBDs (Anaplasma spp., Ehrlichia spp., Borrelia burgdorferi, Leishmania spp., and Dirofilaria immitis) from 2016 through 2020. Geographic distribution of positive tests and relative percent positive values were mapped by the Nomenclature of Territorial Units for Statistics classification for regions with sufficient test results for reporting.

RESULTS

A total of 404,617 samples corresponding to 1,134,648 canine results were available from dogs tested in 35 countries over the 5-year study period. Over this period the number of test results per year increased whereas test positivity decreased. Leishmania spp. had the largest increase in total test results from 25,000 results in 2016 to over 60,000 results in 2020. Test positivity for Leishmania spp. fell from 13.9% in 2016 to 9.4% in 2020. Test positivity fell for Anaplasma spp. (7.3 to 5.3%), Ehrlichia spp. (4.3 to 3.4%), and Borrelia burgdorferi (3.3 to 2.4%). Dirofilaria immitis test positivity trended down with a high of 2.7% in 2016 and low of 1.8% in 2018. Leishmania spp. test positivity was highest in endemic areas and in several non-endemic countries with low numbers of test results. Co-positivity rates were significantly higher than expected for all pathogen test positive pairs except for Ehrlichia spp. with Borrelia burgdorferi and D. immitis with Borrelia burgdorferi.

CONCLUSIONS

This study represents the largest data set on CVBD seropositivity in Europe to date. The increase in the number of test results and decreasing test positivity over the study period may reflect changes in testing behavior and increased screening of healthy animals. The Europe-wide mapping of CVBD provides expected test positivity that can help inform veterinarians' decisions on screening and improve prevention and identification of these important, sometimes zoonotic, diseases.

A Questionnaire-Based Survey on the Long-Term Management of Canine Leishmaniosis by Veterinary Practitioners

Simple Summary

Canine Leishmaniosis is a chronic and potentially fatal disease, caused by Leishmania infantum, a zoonotic microorganism. In economically disadvantaged regions, costs associated with long-term patient monitoring may determine that some owners decline veterinary follow-up of their dogs, with potentially severe implications for animal welfare and public health. This online, questionnaire-based survey aimed to assess how Portuguese veterinary practitioners perform long-term patient management and recognize relapses. More than half of the respondents stated that most dog owners declare having financial restraints, which condition the use of diagnostic tests during long-term follow-up. Allopurinol ad aeternum or until disease remission and domperidone were the most prescribed treatment, and relapses were detected by the reappearance or worsening of clinical signs by most veterinary practitioners. The rate of relapse detection was higher in the most economically favored regions, probably because of a lesser constraint on the use of the appropriate diagnostic tests. This study confirms that owner financial restraints negatively influence veterinary follow-up and relapse recognition, potentially compromising clinical decision making and favoring the maintenance of Leishmania infantum infection endemic status in Portugal.

Abstract

Canine Leishmaniosis (CanL) is a chronic and potentially fatal disease. In economically disadvantaged regions, costs associated with long-term patient monitoring may determine that some owners decline veterinary follow-up of their dogs. This online, questionnaire-based survey aimed to assess how Portuguese veterinary practitioners perform long-term patient monitoring and recognize relapses. More than 50% of respondents reported that 50–100% of dog owners declared financial restraints. Hence, in these circumstances, most veterinary practitioners only performed clinical examination and serology. However, when owners did not declare financial restriction, other tests were additionally performed, such as renal and hepatic profiles, hemogram, serum protein electrophoresis and urine protein creatinine ratio. The mean number of exams performed when owners presented financial restraints was significantly lower than the number of exams performed without economic limitations. Most veterinary practitioners prescribed allopurinol ad aeternum or until disease remission and domperidone. CanL relapses were recognized by more than half of respondents “Always”, through the reappearance or worsening of clinical signs, whereas about a quarter detected an increase in anti-Leishmania antibody levels and identified abnormalities in the serum protein electrophoresis profile. The relapse rate was higher in the Lisbon Metropolitan Area and north, the most economically favored regions of Portugal. This study confirms that owner financial restraints negatively influence veterinary follow-up and relapse recognition, ultimately compromising clinical decision making and favoring the maintenance of Leishmania infantum infection endemicity.

Diagnosis and clinical management of canine leishmaniosis by general veterinary practitioners: a questionnaire-based survey in Portugal

BACKGROUND

Canine leishmaniosis (CanL) can be appropriately managed following international recommendations. However, few studies have assessed the preferred protocols in real-life veterinary practice and whether these are in line with the guidelines. This survey aimed to investigate the current trends in the clinical management of CanL among veterinary practitioners in Portugal, taking into consideration different scenarios of infection/disease and the awareness of and application by veterinary practitioners of the current guidelines.

METHODS

A questionnaire-based survey was conducted online using an electronic platform. The following topics were surveyed: (i) general characteristics of the responding veterinarian; (ii) the preferred protocols used for the diagnosis, treatment and prevention of CanL, considering different theoretical scenarios of infection/disease; and (iii) the responding veterinarian's current knowledge and application of the existing guidelines on CanL. After internal validation, the survey was distributed online, for 2 months, via Portuguese social network veterinary groups. Data were collected for descriptive analysis.

RESULTS

Eighty-six replies were obtained. Analysis of the results showed that the preferred diagnostic techniques varied widely according to the theoretical scenario of infection/disease. In general daily practice, serology testing (enzyme-linked immunosorbent assay [ELISA]) was the most used tool (67.4%). The preferred matrices used for PCR test were lymph nodes (62.3%) and/or bone marrow (59.0%). Regarding treatment, for subclinical infection/stage I CanL, 51.2% of the respondents did not prescribe any medical treatment, but 98.8% proceeded with both monitoring and preventive measures. Among those who prescribed a treatment (n = 42), most chose domperidone (47.6%). For the treament of stages IIa, IIb and III CanL, allopurinol/meglumine antimoniate (MA) was chosen by 69.8, 73.3 and 51.2% of respondents, respectively, followed by allopurinol/miltefosine (20.9, 19.8 and 38.4%, respectively). In contrast, dogs with stage IV CanL were mostly treated with allopurinol/miltefosine (48.8%) rather than with allopurinol/MA (23.3%). The use of repellents was the preferred preventive strategy (98.8%). About 93.0% of responders were aware of the existence of guidelines, and most of these veterinarians consulted the guidelines of the LeishVet group and the Canine Leishmaniosis Working Group; however, 31.3% reported that they did not follow any specific recommendations.

CONCLUSIONS

Of the veterinarians responding to the survey, most reported following international guidelines for the clinical management of CanL. While allopurinol/MA was the preferred therapeutic protocol for the treatment of stages II/III CanL, allopurinol/miltefosine was the first choice for the treatment of stage IV CanL, possibly due to the unpredictable effect of MA on renal function. This study contributes to a better understanding of the trends in practical approaches to the treatment of CanL in Portugal.

Seroprevalence and risk factors associated with Leishmania infantum in dogs in Sardinia (Italy), an endemic island for leishmaniasis

Leishmaniasis is a widespread, vector-borne parasitosis causing clinical manifestations in animals and in humans. In dogs, Canine Leishmaniasis has been reported in as much as 50 countries and the Mediterranean basin is known to be one of the most affected zones. Within these areas, the Island of Sardinia (Italy) has long been considered endemic for leishmaniasis and the presence of two arthropod vectors has recently been reported there. Nevertheless, to date, no epidemiological surveys regarding CanL have been carried out on the island. Hence, for the first time, the seroprevalence and the risk factors were investigated. Blood samples, as well as clinical and general information from 1.147 dogs, were collected and analyzed. Dogs consisted of two distinct populations, namely "owned dogs" and "kennel dogs." Anti-Leishmania IgG antibodies were detected using IFAT and samples were scored as positive at a cut-off dilution of 1:80. Data was analyzed using a Chi-squared test and bivariate and multivariate analyses were performed. Overall, 15.4% of dogs were found to be infected with CanL while only 44.1% of these animals exhibited clinical signs. Owned dogs (27.2%) were found to be infected more often than kennel dogs (10.6%); male dogs were found to be more frequently infected than female dogs and the number of infected animals increases with age. The present survey confirmed the endemic nature of leishmaniasis in Sardinia with a similar seroprevalence as mainland Italy. The results obtained serve as validation for the hypothesis that, in endemic areas, clinical CanL representations constitute only a fraction of the leishmaniasis cases.

Current Distribution of Selected Vector-Borne Diseases in Dogs in Spain

Currently, climate change, modifications of landscapes and habitats due to human activities, as well as an increase in the movement of reservoirs and new species of competent vectors, have contributed to the spread of canine vector-borne diseases. These are mostly emerging and neglected diseases, some of them with zoonotic potential. Therefore, the objective of this study was to assess the prevalence and distribution of four major canine vector-borne diseases (Dirofilaria immitis, Leishmania infantum, Anaplasma spp., and Ehrlichia canis) in Spain. Between September 2018 and February 2020, blood was sampled from 4643 client-owned dogs from 111 veterinary clinics from the 17 autonomous communities of Spain. All samples were tested for the detection of D. immitis antigens, and for antibodies against L. infantum, Anaplasma spp. and E. canis. Of the studied dogs, 22.14% were positive for one or several diseases while the prevalence was 6.25% (CI: 5.59–6.98) for D. immitis, and the seroprevalences were 10.36% (CI: 9.52–11.27) for L. infantum, 5.06% (CI: 4.47–5.73) for Anaplasma spp., and 4.26% (CI: 3.72–4.88) for E. canis. Co-infections by two and three vector-borne diseases were reported in 13% and 2% of the infected dogs, respectively. The studied vector-borne diseases are widely distributed throughout the Spanish geography, being observed and expanding northward in the case of D. immitis and L. infantum. The results point to an insufficiency of preventive measures to avoid the infection, and the need of the implementation of awareness campaigns among veterinarians and owners. Furthermore, a close collaboration between veterinarians, physicians and health authorities would be necessary for such zoonotic vector-borne diseases.

Serological evaluation of selected vector-borne pathogens in owned dogs from northern Spain based on a multicenter study using a commercial test

Background

Environmental conditions in northern Spain allow the development of different arthropods involved in the transmission of significant canine vector-borne pathogens. The aim of the study was to systematically assess seroprevalence rates for Leishmania infantum, Ehrlichia canis, Anaplasma spp., Dirofilaria immitis and Borrelia burgdorferi, and risk factors in dogs from all regions of the north of Spain.

Methods

A total of 556 dogs were included in this study between January 2017 and December 2018, belonging to 30 practices covering all regions in northern Spain (Galicia, Asturias, Cantabria, Basque Country, Navarra, Aragon and Catalonia). All practices were located in the north of every region. Blood samples were analyzed using the 4DX SNAP® test (IDEXX Laboratories, Westbrook, Maine, USA) for the detection of D. immitis antigen and E. canis, B. burgdorferi and Anaplasma spp. antibodies. Leishmania SNAP® test (IDEXX Laboratories) was used for detection of L. infantum antibodies. Associations between prevalence of canine vector-borne pathogens, epidemiological and clinical signs data were statistically analyzed.

Results

The overall prevalence rates were 8.99% for L. infantum, 1.26% for Anaplasma spp., 0.9% for E. canis, 0.72% for B. burgdorferi, and 0.18% for D. immitis. Globally, 11.33% of the dogs included in the study were positive to any tested vector-borne pathogen. Leishmania infantum seroprevalence was the highest and the only one detected in all the regions. Leishmania infantum seropositivity was associated with age > 10 years-old, outdoor access, anemia, fever, dermatological signs, lympadenomegaly, muscular atrophy, ocular signs and renal disease. Ehrlichia canis seropositivity was associated with the summer season and living in urban areas. Apathy, weakness, anorexia, weight loss, anemia, fever and gastrointestinal clinical signs were also associated with E. canis antibody detection. Living in a rural area was also a risk factor for Anaplasma spp. and B. burgdorferi seropositivity.

Conclusions

To our knowledge, this is the first multicenter survey performed in northern Spain assessing different canine vector-borne diseases from all regions. Results show the presence of autochthonous cases of these diseases. The vector-borne pathogens found in this study should be included in the differential diagnosis in dogs from some areas previously considered non-endemic for these pathogens.

Latest trends in L. infantum infection in dogs in Spain, Part II: current clinical management and control according to a national survey of veterinary practitioners

Background

Canine leishmaniosis (CanL) is a parasitic zoonotic disease, endemic in the Mediterranean basin including Spain. While knowledge about CanL, its management, treatment, prevention and control mounts, it remains unclear whether all clinical veterinarians follow the same international recommendations, such as those of the LeishVet group. This study was thus designed to assess recent trends in the clinical management of CanL in veterinary clinics across Spain through a questionnaire-based survey. Results were compared with those of a prior national multicenter questionnaire administered by our research team in 2005.

Methods

A questionnaire consisting of 28 questions about CanL was developed using Google Forms and distributed by email to 1428 veterinary clinics in Spain. Questions were designed to obtain data on common clinical signs, techniques and complementary exams used to diagnose the disease, and on its monitoring, treatment and control measures. Data were collected in a database for statistical analysis.

Results

Completed questionnaires were returned by 295 clinics. Compared to the situation in 2005, responses indicate that clinical signs of CanL have not changed significantly, cutaneous lesions being still the most prevalent sign observed by practitioners. Quantitative serological techniques are considered an adequate approach to diagnosis, provided their results are supported by the findings of a thorough physical exam, as well as complementary tests (complete blood count, biochemical profile, plasma protein electrophoretogram and complete urinalysis). Treatment protocols and check-ups follow international recommendations. Finally, a multimodal approach is being endorsed to adequately control CanL including preventive measures such as annual serological check-ups and the combination of repellents and vaccines. Additionally, owners are being better informed about CanL by veterinarians, which translates to the improved control of this zoonosis.

Conclusions

The clinical management of CanL has recently undergone significant changes owing to improvements in clinical knowledge of the disease, more unified international criteria, improved diagnostic techniques and their adequate interpretation, as well as a greater awareness of the disease transmitted to owners.

Latest trends in Leishmania infantum infection in dogs in Spain, Part I: mapped seroprevalence and sand fly distributions

Background

This report describes L. infantum infection seroprevalence in dogs in Spain through data obtained from peer-reviewed literature and a cross-sectional serological survey assessing epidemiological and habitat variables as risk factors for infection. The study also provides preliminary sand fly species distribution data and indicates factors affecting their distribution and density.

Methods

Three different studies were conducted in Spain: (i) a peer-reviewed literature seroprevalence survey (1985–2019); (ii) a cross-sectional serological survey (2011–2016); and (iii) a preliminary entomological survey (2013–2014). In the cross-sectional serological survey, 1739 dogs from 74 different locations including 25 Spanish provinces were tested for L. infantum by indirect immunofluorescence antibody test (IFAT) (antibody titre ≥ 1:100). Seroprevalence of L. infantum infection was analysed by province and bioclimatic zone. Statistics were used to analyse relationships between several dog- and environment-related variables and L. infantum seroprevalence. In parallel, during 2013–2014, sand flies were collected across the Iberian Peninsula and the Balearic Islands using CDC light traps to examine relationships between habitat-related factors and sand fly species densities (number of sand flies per trap per hour).

Results

The literature review revealed that the provinces showing the highest seroprevalence were Balearic Islands (57.1%), Ourense (35.6%), Málaga (34.6%) and Cáceres (34.2%), and those showing the lowest seroprevalence were Vizcaya (0%), Cantabria (2.0%) and Álava (3.3%). In our survey, anti-Leishmania IgG antibodies were detected in 176 of the 1739 dogs rendering a seroprevalence of 10.12%. Percentage seroprevalence distributions significantly varied among bioclimatic belts. Seropositivity for L. infantum was related to size (large breed dogs versus small) and were significantly higher in younger dogs (≤ 1 years-old). In the entomological survey, 676 sand flies of five species were captured: 562 (83.13%) Phlebotomus perniciosus; 64 (9.47%) Sergentomyia minuta; 38 (5.62%) P. ariasi: 6 (0.89%) P. sergenti; and 6 (0.89%) P. papatasi. Phlebotomus perniciosus showed a greater density in the thermo-Mediterranean than in the meso-Mediterranean zone. Densities of S. minuta and P. ariasi were significantly higher in rural habitats.

Conclusions

This updated seroprevalence map of L. infantum infection in dogs in Spain defines non-endemic, hypoendemic, endemic and hyperendemic areas, and confirms P. perniciosus as the most abundant sand fly vector in Spain.

The impact of canine leishmaniosis vaccination with Canileish® in Leishmania infantum infection seroprevalence studies

Effective vaccines against Leishmania parasites are a goal for the scientific community working with both canine and human leishmaniosis. However, possible side effects of vaccination should also be considered and evaluated, preferably before vaccine licensing and marketing. One of these possible effects is the cross-reaction of vaccine-induced antibodies with standard serological tests for detection of Leishmania infantum infection. Longitudinal studies were performed on the type of humoral profile induced by Brazilian marketed canine leishmaniosis vaccines, but little is known regarding the European situation. In this study, an annual follow-up of 85 CaniLeish® vaccinated dogs and 83 non-vaccinated control dogs was performed. Blood samples were taken for all animals at pre-determined time points: before vaccination; immediately before each one of the two following vaccine doses (at 21 days intervals); and then one, four, six, nine and 12 months after finishing the vaccination course. All samples were tested by an in-house ELISA, using a whole promastigote antigen, for the presence of anti-L. infantum antibodies. Humoral response detectable by the used serological diagnostic method was significantly higher in the vaccine group when compared with the control group (p < 0.01) until one-month post-vaccination. Results show that CaniLeish® vaccine-induced antibodies cross-react with a commonly used serological test for diagnosis of L. infantum natural infection. Implications of this interference are discussed, with special emphasis on a possible negative impact on canine leishmaniosis surveillance studies.

Wild mammals as potential silent reservoirs of Leishmania infantum in a Mediterranean area

A molecular survey of wild mammals was performed to assess their potential as reservoirs of L. infantum. A total of 156 specimens of wild mammalian fauna were obtained for analysis from areas in Catalonia with a reported incidence of canine leishmaniasis. They consisted of 124 small mammals: 35 Mus spretus (Muridae); 64 Erinaceus europaeus (Erinaceidae), 25 Sciurus vulgaris (Sciuridae) and 32 carnivores: 11 Vulpes vulpes (Canidae), 1 Felis catus (Felidae), 15 Meles meles, 4 Martes foina and 1 Mustela vison (Mustelidae). The analysis was performed on samples of liver, spleen, skin (ear) and blood extracted from the heart. Leishmania DNA was determined by a qPCR and specific anti-Leishmania antibodies were detected by an in-house (ELISA). Among the 156 specimens studied, 29.48% were positive in at least one of the samples studied and considered infected. In M. spretus, Leishmania DNA was detected in the liver, spleen or skin of 37.1% of 35 specimens, and 2 of the 13 specimens tested serologically were positive (15.38%). In E. europaeus, 34.4% of the 64 specimens were infected. Leishmania DNA was detected in 19/51 spleens and 5/50 skins; 2 of the 37 specimens analysed in both spleen and skin gave positive results in both samples. Serology was positive in 12.8% (6/47) by ELISA; 3 specimens were positive by both ELISA and qPCR. In S. vulgaris, Leishmania DNA was detected in 5 of 25 specimens (20%). Of the 32 carnivore specimens analysed, Leishmania DNA was detected in both samples studied (spleen and liver) of 4 (12.5%) (2 M. foina, 1 M. vison and 1 F. catus), which were not studied serologically. The data obtained indicate that small mammals, above all wild rodents and carnivores, could act as naturally infected hosts of L. infantum in this endemic area. Among the rodents, M. spretus stands out with the highest prevalence of infection. In E. europaeus, the presence of L. infantum DNA in spleen and skin, and antibodies in heart blood, reported here for the first time, indicates this small mammal could be a possible reservoir. Additionally, S. vulgaris, not previously studied as an L. infantum reservoir, showed non-negligible prevalence values, indicating a potential role in leishmaniasis transmission.

Assessment of the insecticidal activity of oral afoxolaner against Phlebotomus perniciosus in dogs

Twelve healthy dogs were included in this laboratory efficacy study. Six dogs were randomly allocated based on body weight to an untreated control group and six to an afoxolaner (NexGard^®) treated group. In the treatment group, afoxolaner was administered orally on Day 0 in accordance with label instructions. On Days 1, 14 and 28, each dog was exposed to 60 unfed female and 10 male Phlebotomus perniciosus sandflies for 1 h. At the end of each exposure period, sandflies were counted and assessed for viability and feeding status. There was no statistical difference in mortality (0.0–5.4%), nor in feeding proportion (61.6–78%) between the control and the treated groups at all 1-h post-exposure assessments. After collection, live fed and unfed sandflies were kept for viability assessments at 48 and 72 h post-exposure. In the untreated control group, the average percentages of live, fed, female sandflies after exposure, on Days 1, 14 and 28, ranged from 51% to 74% at 48 h and from 46% to 57% at 72 h, demonstrating model robustness over the 28 days of the study. Significantly fewer live fed sandflies were recorded for the afoxolaner treated group (p < 0.01). The insecticidal efficacy was 100%, 95.9% and 75.2% at 48 h post Days 1, 14 and 28 exposures, respectively, and 100%, 100% and 86.3% at 72 h post Days 1, 14, and 28 exposures, respectively. A single administration of oral afoxolaner (NexGard^®) to dogs significantly killed P. perniciosus sandflies 48 and 72 h after blood feeding for 1 month.

Seroprevalence of canine Leishmania infantum infection in the Mediterranean region and identification of risk factors: The example of North-Eastern and Pyrenean areas of Spain

The Mediterranean basin is an endemic region for canine leishmaniosis (CanL), where it represents a major veterinary problem and raises human health concerns. However, the distribution of the disease is heterogeneous and not all countries and locations have been equally studied and characterized. This work describes the situation of CanL in Girona province (Catalonia, Spain), for which no data has been previously reported, and presents a relevant study to exemplify other areas with similar characteristics across the region. Four cross-sectional seroprevalence surveys were performed from 2012 to 2016 throughout the province, including 36 sampling stations in 26 localities and a total of 593 dogs. For each animal, individual and location variables were also collected. Additionally, each dog owner answered a questionnaire about their knowledge of CanL and preventive methods used. Blood samples were analysed by an in-house ELISA and a mixed logistic regression model was used to assess the relationship between pre-determined variables and dog seropositivity. A Spearman's correlation was used to assess the association between dog owners' perceived risk of CanL and Leishmania infantum seropositivity in dogs at a given location. The overall true seroprevalence estimated for Girona province was 19.5% (95%CI: 15.5-23.5), of which only 6.8% (10/146) were considered symptomatic. Age of the dog [OR = 1.21 (95%CI: 1.11-1.31); p < 0.001] and altitude [OR = 0.02 (95%CI: 0.001-0.19); p = 0.001] were identified as risk factors for the infection. The results obtained in this study are expected to aid in the implementation of directed control programmes in CanL endemic areas throughout Europe, as well as to provide suitable data for the design of better risk assessment maps of the disease.

Seasonal dynamics of canine antibody response to Phlebotomus perniciosus saliva in an endemic area of Leishmania infantum

Background

Canine leishmaniosis (CanL) is an important zoonotic parasitic disease, endemic in the Mediterranean basin. In this region, transmission of Leishmania infantum, the etiological agent of CanL, is through the bite of phlebotomine sand flies. Therefore, monitoring host-vector contact represents an important epidemiological tool, and could be used to assess the effectiveness of vector-control programmes in endemic areas. Previous studies have shown that canine antibodies against the saliva of phlebotomine sand flies are specific markers of exposure to Leishmania vectors. However, this method needs to be further validated in natural heterogeneous dog populations living in CanL endemic areas.

Methods

In this study, 176 dogs living in 12 different locations of an L. infantum endemic area in north-east Spain were followed for 14 months. Blood samples were taken at 5 pre-determined time points (February, August and October 2016; January and April 2017) to assess the canine humoral immune response to whole salivary gland homogenate (SGH) and to the single salivary 43 kDa yellow-related recombinant protein (rSP03B) of Phlebotomus perniciosus, a proven vector of L. infantum naturally present in this region. Simultaneously, in all dogs, L. infantum infection status was assessed by serology. The relationship between anti-SGH and anti-rSP03B antibodies with the sampling month, L. infantum infection and the location was tested by fitting multilevel linear regression models.

Results

The dynamics of canine anti-saliva IgG for both SGH and rSP03B followed the expected trends of P. perniciosus activity in the region. Statistically significant associations were detected for both salivary antigens between vector exposure and sampling month or dog seropositivity to L. infantum. The correlation between canine antibodies against SGH and rSP03B was moderate.

Conclusions

Our results confirm the frequent presence of CanL vectors in the study area in Spain and support the applicability of SGH- and rSP03B-based ELISA tests to study canine exposure to P. perniciosus in L. infantum endemic areas.

Isoenzymatic characterization of Phlebotomus ariasi and P. perniciosus of canine leishmaniasis foci from Eastern Pyrenean regions and comparison with other populations from Europe

An entomological survey was carried out in 2007 in two Pyrenean counties of Lleida province (north-eastern Spain), where cases of autochthonous canine leishmaniasis have been recently reported. Phlebotomus ariasi and P. perniciosus, vectors of Leishmania infantum in the Mediterranean area, were captured. The aim of the present study was to compare these phlebotomine populations with others captured in known leishmaniasis foci in Europe. Populations of these species were studied by analysing the polymorphism of seven enzymatic systems (HK, PGI, PGM, MDH, 6PGD, FUM and ACO) and compared with other specimens from endemic regions of France, Italy, Malta, Portugal and Spain captured in other campaigns, and also with previously published results. Phlebotomusariasi was more polymorphic than P. perniciosus. Only the ACO locus had diagnostic alleles, but some other alleles show high characteristic frequencies for each species. The neighbour-joining trees separated two population groups in both species. On the basis of the isoenzyme study results, sand fly populations of the Pyrenean region in Lleida province are closely related to those of other nearby leishmaniasis endemic regions in France and Spain.

Management, prevention and treatment of canine leishmaniosis in north-eastern Spain: an online questionnaire-based survey in the province of Girona with special emphasis on new preventive methods (CaniLeish vaccine and domperidone)

Knowledge of how canine leishmaniosis (CanL) is being managed clinically and its epidemiology is very important, since dogs are the main reservoir of human leishmaniosis. This study reports the results obtained through a questionnaire-based survey of veterinary practitioners in Girona province, a recognised, but non-documented endemic area in north-eastern Spain. The primary objective was to obtain data on the clinical management of CanL, focusing particularly on new preventive methods and therapeutic tools. The results show an extensive routine management of CanL cases and a widespread use of the CaniLeish (Virbac) vaccine and domperidone (Leisguard, Esteve). Adverse reactions were detected by a vast majority of the vaccine users (82 per cent), the most frequent being local reactions, apathy, fever and gastroenteritis. All the respondents had treated confirmed cases, and the therapeutic protocol most used was the combination of meglumine antimoniate (Glucantime, Merial) and allopurinol (Zyloric, GlaxoSmithKline).

Identification of blood meals in field captured sand flies by a PCR-RFLP approach based on cytochrome b gene

Leishmaniasis is a vector-borne disease transmitted by phlebotomine sand flies. Information about blood meal preferences in sand flies is essential to understand the epidemiology of the disease to adopt control measures. In previous studies, a polymerase chain reaction (PCR) of 359bp fragment of the conserved gene cytochrome b (cyt b) and further sequencing were applied in the study of blood meal sources in sand flies collected in the area of a leishmaniasis outbreak in southwest Madrid, Spain, providing significant information about blood meal preferences in the focus. In this work, a PCR-restriction fragment length polymorphism (RFLP) targeting a fragment of 359bp of vertebrate cyt b gene was developed. Restriction endonucleases HaeIII and HinfI generated specific patterns consistent with the blood meal sources found in sand flies. The protocol has been validated with twenty six engorged females collected in the field with CDC traps. Blood meals from nine vertebrates were identified based on PCR-cyt b and sequencing-human, dog, cat, horse, hare, rabbit, sheep, goat and chicken - and mixed blood meals (sheep/human; sheep/goat) - and successfully distinguished by PCR-RFLP. Therefore, this approach is an efficient and reliable alternative method to be applied in entomological surveys.

Estimation of canine Leishmania infection prevalence in six cities of the Algerian littoral zone using a Bayesian approach

A large-scale study on canine Leishmania infection (CanL) was conducted in six localities along a west-east transect in the Algerian littoral zone (Tlemcen, Mostaganem, Tipaza, Boumerdes, Bejaia, Jijel) and covering two sampling periods. In total 2,184 dogs were tested with an indirect fluorescent antibody test (IFAT) and a direct agglutination test (DAT). Combined multiple-testing and several statistical methods were compared to estimate the CanL true prevalence and tests characteristics (sensitivity and specificity). The Bayesian full model showed the best fit and yielded prevalence estimates between 11% (Mostaganem, first period) and 38% (Bejaia, second period). Sensitivity of IFAT varied (in function of locality) between 86% and 88% while its specificity varied between 65% and 87%. DAT was less sensitive than IFAT but showed a higher specificity (between 80% and 95% in function of locality or/and season). A general increasing trend of the CanL prevalence was noted from west to east. A concordance between the present results and the incidence of human cases of visceral leishmaniasis was observed, where also a maximum was recorded for Bejaia. The results of the present study highlight the dangers when using IFAT as a gold standard.

Management of canine leishmaniosis in endemic SW European regions: a questionnaire-based multinational survey

Background

Canine leishmaniosis (CanL) caused by Leishmania infantum is a widespread endemic disease in SW Europe. This study was designed to determine how veterinarians clinically manage CanL in this region by analysing information collected in a questionnaire completed by local veterinarians working in clinics in France, Portugal, Greece, Spain, Italy and Slovenia.

Methods

Over the period 2004–2011, a questionnaire on CanL was sent to 12,546 small animal clinics located in the six countries surveyed. The questionnaire with 10 items comprising open and closed questions sought to obtain comparable data regarding the main clinical manifestations of CanL, the diagnostic methods used, the treatment regimens selected, recommended preventive measures and awareness of the important public health implications of CanL.

Results

The data collected reflect similarities in the clinical manifestations reported although there was some variation in the concurrent diseases described, and wide variation in the clinical management of CanL among the countries examined in terms of dosing regimens, therapeutic agents and the criteria used to diagnose CanL. Most veterinarians properly informed dog owners about the preventive measures available and about the zoonotic implications of CanL.

Conclusions

This survey describes the current situation in SW endemic countries in Europe regarding the clinical management of CanL. The data collected reveal a need to unify criteria from evidence-based medicine to determine and similarly apply the best diagnostic and treatment methods available for this disease in the different countries.

Evidence for widespread Leishmania infantum infection among wild carnivores in L. infantum periendemic northern Spain

Leishmania spp. infection was investigated in tissue samples of wild carnivores from the Spanish Basque Country (BC), by PCR and DNA sequencing. The region is at the northern periphery of Leishmania infantum endemic Iberian Peninsula and infection in the dog (reservoir) or other species has not been previously reported. Leishmania kinetoplast DNA was detected by real-time PCR (rtPCR) in 28% (44/156) of animals. Specifically, in 26% of Eurasian badgers (n=53), 29% of foxes (n=48), 29% of stone martens (n=21) and in 25-50% of less numerous species including genets, wild cats, pole cats, European mink and weasels. Infected animals particularly badgers, were most prevalent in the southernmost province of the BC (Araba) in areas dominated by arable land. Subsequent amplification and sequencing of a fragment of the rRNA internal transcribed spacer 2 (ITS2) from a subset of rtPCR positives samples confirmed the species as L. infantum, showing a high sequence homogeneity with ITS2 sequences of L. infantum from dogs and humans from southern Spain. In summary, this study reports for the first time L. infantum infection in wild carnivores from the BC including in stone martens, pole cats and minks in which infection has not been previously described. It supports the need to study infection in dogs and people in this region and is an example of the value of infection surveillance in wildlife to assess potential risks in the domestic environment and their role in spreading infections in non-endemic areas.

Temporal trends in canine leishmaniosis in the Balearic Islands (Spain): a veterinary questionnaire. Prospective canine leishmaniosis survey and entomological studies conducted on the Island of Minorca, 20 years after first data were obtained

Leishmaniosis is present in the Mediterranean region of Europe, where Leishmania infantum is responsible for the disease, dogs are the main reservoir, and sand flies of the Phlebotomus genus, subgenus Larroussius, are proven vectors. Some areas, including Minorca in the Balearic Islands, are considered free of the disease, despite the presence of vectors. However, in the context of the current expansion of canine leishmaniosis in parts of Europe, an epidemiological study using a veterinary questionnaire was carried out to establish the current situation of the disease in the Balearic Islands. While 50% of veterinarians thought that the incidence of canine leishmaniosis had not changed over time, 26.2% perceived an increasing trend, mainly those from Minorca, where most of the veterinarians polled (88.1%) considered the new diagnosed cases as autochthonous. A cross-sectional serological study performed in this island gave a seroprevalence rate of 24%. Seroprevalence among animals of local origin and with no history of movements to endemic areas was 31%. The presence of autochthonous canine leishmaniosis in Minorca was not correlated with an increase in vector density. The environmental and climatic factors that influenced the distribution and density of Phlebotomus perniciosus on the island and the possible causes of the apparent emergence of canine leishmaniosis in Minorca are discussed.

Seropositivity rates for agents of canine vector-borne diseases in Spain: a multicentre study

Background

Controlling canine vector-borne diseases (CVBD) is a major concern, since some of these diseases are serious zoonoses. This study was designed to determine seropositivity rates in Spain for agents causing the following five CVBD: leishmaniosis (Leishmania infantum: Li), heartworm (Dirofilaria immitis: Di), ehrlichiosis (Ehrlichia canis: Ec), anaplasmosis (Anaplasma phagocytophilum/Anaplasma platys: An) and Lyme disease (Borrelia burgdorferi: Bb).

Methods

Anti-An, -Bb, and -Ec antibodies and the Di antigen were determined using the 4DX SNAP® Test (IDEXX Laboratories) and anti-L. infantum (Li) antibodies using the Leishmania SNAP® Test (IDEXX Laboratories) in blood and/or serum samples.

Results

Among 1100 dogs examined, overall seropositivity rates were: Li (15.7%), Ec (5%), An (3.1%), Di (1.25%) and Bb (0.4%). While seropositivity towards Bb and Di was similar in all geographic regions, rates were significantly higher in the east of Spain (8.3%) for An, significantly higher in the north (20%) for Ec, and significantly higher in the Southeast (46.6%) and South (27.4%), and significantly lower in the north (0%) for Li.

No statistical associations were observed between sex and the CVBD analyzed (p ≥ 0.05) while the following associations with other variables were detected: a higher seropositivity to Ec (40%) and Bb (6.7%) in dogs under one year of age compared with adults (p < 0.05); and a higher seropositivity to An and Li in dogs that lived outdoors versus indoors (p = 0.01; p < 0.001, respectively). Seropositivity rates of 2.1%, 0%, 1.7%, 0.5% and 4.2% were recorded respectively for An, Bb, Ec, Di and Li in dogs with no clinical signs (n = 556) versus 3.8%, 0.6%, 7.5%, 1.8% and 25.9% for those with signs (n = 507) suggestive of a CVBD.

Conclusion

The data obtained indicate a risk for dogs in Spain of acquiring any of the five CVBD examined. Veterinarians in the different regions should include these diseases in their differential diagnoses and recommend the use of repellents and other prophylactic measures to prevent disease transmission by arthropod vectors. Public health authorities also need to become more involved in the problem, since some of the CVBD examined here also affect humans.