Leishmania infantum infection serosurveillance in stray dogs inhabiting the Madrid community: 2007–2018

Abstract

Background Leishmaniosis is an endemic zoonotic disease in the Mediterranean basin caused by Leishmania infantum and transmitted by phlebotomine sandflies. While in dogs disease may be severe, leishmaniosis is also a public health concern as was shown in the largest outbreak of human leishmaniosis (HL) in Europe in 2009 occurring in the Madrid region. The aim of the present study was to assess the applicability of the Leishmaniosis Surveillance Program (LeishSP) established in Madrid in 1996 by examining trends in L. infantum seroprevalence and associated epidemiological risk factors based on data for the 2007–2018 period. Methods The study population consisted of 3225 stray dogs from 17 animal shelters collaborating with the LeishSP. Seroprevalences were recorded twice annually (April and November) from 2007 to 2018. In each yearly period, a minimum of 100 dogs were tested to detect dogs infected before and after the sandfly risk season in Madrid area. Each dog was subjected to the same protocol of blood sample collection and clinical examination to collect epidemiological data and clinical signs. Anti-Leishmania-specific IgG was determined by IFAT cut-off ≥ 1:100. Results Overall seroprevalence was 6.1% (198 positive dogs). Epidemiological data indicate a significantly higher seroprevalence in dogs > 4 years old, purebred dogs (Pit Bull and related breeds), and medium to large size dogs. There were no seroprevalence differences according to sex and/or season (April and November). In addition, no significant differences were observed according to whether dogs lived inside or outside the HL outbreak area. Remarkably, of 198 dogs testing positive for L. infantum, 64.6% had no clinical signs, indicating a high proportion of clinically healthy infected dogs that could be a potential source of infection. Conclusions Results indicate a stable seroprevalence of L. infantum infection after 2006 in stray dogs in Madrid but with a recent slightly increasing trend. These observations support the need to continue with the LeishSP implemented by sanitary authorities of the Madrid Community as an early warning strategy for human and animal leishmaniosis and to enable continued assessment of the epidemiological role of dogs with subclinical infection in this important zoonotic disease. Graphical Abstract

Twenty-year evolution of Leishmania infantum infection in dogs in Valdeorras (Galicia, Northwestern Spain): implication of climatic factors and preventive measures

“…Historically, dogs in rural areas of Spain, like Valdeorras, often lived outdoors, increasing their exposure to sand flies and, consequently, to L. infantum infection [ 14 , 42 – 44 ]. However, contemporary trends indicate a shift towards dogs living indoors and experiencing improved lifestyles.…”

Determination of the effect of collars containing 10% w/w imidacloprid and 4.5% w/w flumethrin (Seresto®) on the incidence of Leishmania and other canine vector-borne pathogen infections in Greece

“…All of the above apply at large to Leishmania infantum , the causative agent of human and canine leishmaniosis, which is one of the world’s most important zoonotic parasites, with a continuous spread from the Mediterranean areas to continental Europe [ 5 , 6 ]. Most infected individuals remain asymptomatic, but the role of such asymptomatic individuals as ‘parasite carriers’ is still under careful consideration [ 7 , 8 ].…”

Serological survey of Leishmania infantum in apparently healthy dogs in different areas of Spain

“…Thus, a wide spectrum of clinical manifestations is documented in dogs with leishmaniosis (Solano‐Gallego et al., 2011 ). Furthermore, in endemic regions, such as Spain, there is a high prevalence of L. infantum infection in apparently healthy dogs (Baxarias, Homedes, et al., 2022 ; Müller et al., 2022 ), although the prevalence of clinical illness is frequently lower than 10% (Solano‐Gallego et al., 2009 ).…”