Diagnosis and epidemiology of canine leishmaniasis in southeastern Bahia, Brazil

Abstract

ABSTRACT. Leishmaniasis is a disease caused by protozoa of the genus Leishmania. Two distinct forms are recognized: visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). In the Americas, the causative agent of VL is L. infantum chagasi, whereas L. braziliensis is principally responsible for CL. Domestic dogs constitute the main source of VL in urban environments, and have also been implicated in CL epidemiology. We carried out molecular and serological surveys to detect Leishmania infection in dogs from the municipality of Ituberá in Bahia, Brazil. Furthermore, we identified risk factors associated with illness in dogs from this locality. Blood samples were collected from 399 dogs and tested using an indirect immunofluorescence assay (IFA) and polymerase chain reaction (PCR) to detect Leishmania spp antibodies and L. infantum chagasi and L. braziliensis DNA, respectively. Dogs were clinically evaluated and tissue samples from those exhibiting skin lesions were examined for parasites. In addition, the dog owners completed an epidemiological questionnaire to identify factors associated with infection. Skin lesions consistent with CL were found on 37 (9.3%) of the evaluated animals, but parasitological examination was negative for all samples. The IFA returned positive results for 60 (15%) dogs. PCR identified DNA from L. braziliensis in 86 (21.6%) animals, where as all samples proved negative for L. infantum chagasi. The 134 dogs (33.6%) testing positive using IFA and/ or PCR were considered infected, and of these, only 13 demonstrated skin lesions. Animals from rural areas were 3.39-times more likely to be infected compared to those in urban environments.

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

“…In this survey, habitat was identified as a risk factor, with dogs from rural areas being more exposed to infection. This finding corresponds to those reported in similar studies and could be due to dogs being in close proximity to non-domestic animals and to disease vectors, given that transmission can also occur in the wild (Oliveira et al 2016). However, other studies (Queiroz et al 2009) reported higher prevalence among dogs living in urban environments and others did not detect any effect of type of habitat at all (Velez et al 2019).…”

“…These factors are controversial, with some authors suggesting it is not relevant whether animals are kept mainly indoors or outdoors (Zivicnjak et al 2005), and others who claim that serological positivity to Leishmania sp. is significantly associated with an outdoor lifestyle (Gálvez et al 2010;Coura-Vital et al 2011;Belo et al 2013;Oliveira et al 2016). Moreover, sedentary animals and those that remain in restricted spaces seemed to have a greater risk of infection as they represent easier targets for the sand flies (Curi et al 2014).…”

Canine Leishmaniosis in Greece: An Updated Countrywide Serological Study and Associated Risk Factors

“…In this study, the risk of infection was higher in dogs kept mainly outdoors than those with an indoor lifestyle. The dog’s lifestyle is a controversial factor, with several authors proposing it is not relevant whether animals live mainly indoors or outdoors [ 23 , 49 , 58 , 64 ] and others who affirm that seropositivity is undoubtedly associated with an outdoor lifestyle, verifying the results of the present study [ 32 , 57 , 65 , 66 ]. Logically, the spread of the infection is expected to be higher in dogs spending most of the time outdoors than those living indoors, because the latter are more unprotected from vector action.…”

Leishmania infection in rodents in Greece

“…To the best of the authors’ knowledge, there are no available relevant data about Leishmania infection of rodents. However, in analogous results regarding canine leishmaniosis, it has been demonstrated that dogs in rural areas are at higher risk of infection compared to urban areas . A possible explanation for this is that semi‐urban areas are richer in vegetation and trees, favouring the development of sand flies and also have a dog population that spends more time outdoors, a proven risk factor for canine leishmaniosis .…”