Prevalence of Leishmania infantum Infection in Dogs Living in an Area of Canine Leishmaniasis Endemicity Using PCR on Several Tissues and Serology

Abstract

We studied and compared the prevalence of Leishmania infection and the seroprevalence and the prevalence of canine leishmaniasis in an area where canine leishmaniasis is endemic. One hundred dogs living on the island of Mallorca (Spain) were studied. In this study, we clinically examined each dog for the presence of symptoms compatible with leishmaniasis, determined the titer of anti-Leishmania antibodies, and investigated the presence of Leishmania DNA by PCR in skin, conjunctiva, and bone marrow samples of each dog. The prevalence of the disease and the seroprevalence were 13 and 26%, respectively. In 63% of the dogs, Leishmania DNA could be detected by PCR in at least one of the tissues studied. The results of positive PCR in the bone marrow, the conjunctiva, and the skin were 17.8, 32, and 51%, respectively. The prevalence of the infection, 67%, was calculated using all animals that were seropositive and/or positive by PCR with any tissue. The results showed that the majority of dogs living in an area where canine leishmaniasis is endemic are infected by Leishmania and that the prevalence of infection is much greater than the prevalence of overt Leishmaniarelated disease.Canine leishmaniasis is a severe systemic disease of dogs caused by the protozoan parasite Leishmania infantum. Clinical manifestations of the disease include nonpruritic skin lesions, such as exfoliative dermatitis and ulcerations, local or generalized lymphadenopathy, loss of weight, poor appetite, ocular lesions, epistaxis, lameness, renal failure, and diarrhea (5,9,14,25). Leishmaniasis is a zoonotic disease for which dogs are considered the chief reservoir of the parasite. The disease is endemic in the Mediterranean basin, where seroprevalence ranges between 10 and 37% (10, 24). There are, however, several studies suggesting that the rate of infection is higher than the figures found by serological investigations. A survey performed using the PCR and immunoblotting techniques found that most dogs living in southern France had been exposed to Leishmania (3). These results agree with another study that found a rate of Leishmania infection of 65% for dogs living in Portugal by using serology and cell-mediated tests (4).The percentage of infected dogs living in an area where canine leishmaniasis is endemic has major public health implications. It was demonstrated that infected, but asymptomatic, dogs were sources of the parasite for phlebotomine vector sandflies and as a consequence play an active role in the transmission of Leishmania (15).The present study was designed to investigate and compare the prevalence of Leishmania infection, the seroprevalence and the prevalence of the disease in a canine population living in an area where canine leishmaniasis is endemic. One hundred dogs living on the island of Mallorca (Spain) were included in this study. Veterinarians clinically examined all dogs, and the titer of anti-Leishmania antibodies was determined. The presence of Leishmania DNA in each dog was investigated by PCR with three tissues: ...

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“…Moreover, clinical disease, accompanied by seroconversion or PCR detection of Rc DNA has not been described in dogs from endemic regions. For this reason, the According to our results, Li seroprevalence in Mallorca is 29.3%, which is similar to a previous study (26%) [37]. Unsurprisingly, statistically significant differences were found between seroprevalences in clinically healthy (15%) and sick dogs (49.3%) further supporting the importance of Li infection as a cause of clinical disease in dogs in the Mediterranean basin.…”

“…Unsurprisingly, statistically significant differences were found between seroprevalences in clinically healthy (15%) and sick dogs (49.3%) further supporting the importance of Li infection as a cause of clinical disease in dogs in the Mediterranean basin. It is well known that the detection of Li antibodies correlates with clinical disease in dogs with leishmaniasis [30,37]. Furthermore, higher seroprevalences were found in dogs from Tarragona (51.7%) and Barcelona (65%) perhaps due to the fact that there were higher proportions of sick dogs compared to Mallorca in the samples obtained in these cities.…”

“…An ELISA was performed as previously described [37]. Briefly, microtitre plates (Costar, 96 well flat bottom, polystyrene microplates/#3590) were coated with 20 μg·mL -1 of Li antigen and incubated overnight at 4 °C.…”

First epidemiological study on exposure to Neospora caninum in different canine populations in the Algiers District (Algeria)

“…For example in areas endemic for canine leishmaniosis (Leishmania infantum) in the Mediterranean basin studies using PCR have confirmed that the prevalence of infection in dogs is much higher than the proportion that actually develops symptomatic disease or even specific antibodies [55,56]. By instance in 73 clinically healthy hunting dogs in Greece, 12.3% tested positive by using serology, whereas 63% tested positive by PCR [57].…”

Canine visceral leishmaniasis: seroprevalence survey of asymptomatic dogs in an endemic area of northwestern Iran

“…Asymptomatic dogs composed of more than fifty percent of the infected animals that were capable to transmission of disease by vector (Solano-Gallego et al 2001;Sousa et al 2011). Based on previous studies in endemic areas of CVL in Iran, 13-24 % of infected dogs had clinical manifestations thus, almost 75 % of infected dogs were asymptomatic (Mohebali et al 2005;Mohebali et al 2011).…”