Background: Leishmaniosis are anthropozoonosis caused by protozoa of the genus Leishmania, representing a complex of
diseases with significant diversity epidemiological and clinical spectrum and can affect 40% of the canine population.
Infected dogs may be asymptomatic or may develop canine leishmaniasis (CL), a severe and progressive disease associated
with the appearance of clinical signs. Serological tests are frequently used for screening of dogs, however, these techniques
present limitations in terms of reproducibility and specificity. In this way, information on the geographical distribution and
prevalence of CL is essential to the implementation of appropriate control measures. Therefore, the aim of this study was to
determine geographical variations in clinical signs and prevalence of Leishmania sp. infections from dogs in Fortaleza, Ceará
state, Brazil.
Materials, Methods & Results: Bone marrow samples of 2829 domestic dogs were collected by puncture for parasitological
diagnosis of canine leishmaniasis (CL), being considered positive by the presence of Leishmania sp. All dogs were examined
and clinical signs were classified as score 0: no clinical signs, score 1: skin lesions, score 2: visceral signs and score 3: skin
lesions + visceral signs. Kruskal-Wallis (P <0.05) was used to compare the scores and parasitological diagnosis among the
seven regions of Fortaleza. So, it was observed that 72% of dogs were positive and the regions I and V had the highest
prevalence (78.3% and 80% respectively), no significant differences among the seven regions. Asymptomatic dogs
represented 55% of infected dogs, and the main clinical sign, among symptomatic dogs (45%), was skin lesion, visualized
in 43% of dogs. Furthermore, 70% of all dogs had ectoparasites.
Discussion: These results show that, despite of the campaign against the disease, there is no great progress in the control of
visceral leishmaniasis in the urban areas like Fortaleza, which present an easy access in the fight against the disease. The
diagnostic in dogs based in the Indirect Fluorescent Antibody Test (IFAT) associated to others factors, like irregular serological
inquiry and no-treated performer personal, perhaps made possible the permanence of susceptibility animals in this area,
beyond of the high number of asymptomatic and no-identified dogs. In this study, it was observed that 55% of dogs were
asymptomatic, without showing evidence of risk of transmission to human population, escaping from controlling methods.
From this we can imply that most of these dogs to LC are asymptomatic and the prevalence did not differ significantly in
different regions of Fortaleza, requiring equal attention throughout the city. Moreover, our results demonstrate that Fortaleza
city has favorable areas for the maintenance of the parasite cycle, with a high risk of transmission to human and canine
population, and it requires special attention because of the large number of asymptomatic cases. Therefore, it is necessary to
control the population of asymptomatic dogs with more efficient controlling methods, with the change of methodology of
serological screening raising the number of detected dogs, reducing the diagnostic time and the use of diagnostic techniques
with levels of specificity higher.
