Diagnostic markers selected by immunoproteomics and phage display applied for the serodiagnosis of canine leishmaniosis.

Canine leishmaniosis (CanL) is one of the most important parasitic diseases found in several countries worldwide. Dogs are considered important domestic reservoirs of the parasites, being relevant in the maintenance of transmission cycle of the disease between sandflies and humans. However, the prevalence of asymptomatic infection is considerably higher than that of apparent clinical illness in the infected animals; thus making promptly necessary to diagnose the infection in these animals, which could help to allow to the adoption of more efficient control measures against disease. Parasitological tests, which are considered as gold standard to demonstrate the infection and diagnose the disease, present problems related with their sensitivity. Also, the sample´s collect is considered invasive. As consequence, serological tests could be applied as an additional tool to detect the asymptomatic and symptomatic CanL. For this purpose, distinct recombinant antigens have been studied; however, problems in their sensitivity and/or specificity have been still registered. The present review focus in advances in the identification of new diagnostic targets applied for the CanL diagnose, represented here by recombinant single, combined or chimeric proteins, as well as by peptides that mimic epitopes (mimotopes); which were selected by means of immunoproteomics and phage display.

Prevalence of visceral leishmaniasis in A population of free-roaming dogs as determined by multiple sampling efforts: A longitudinal study analyzing the effectiveness of euthanasia.

Free-roaming dogs affected by visceral leishmaniasis (VL) contribute to the geographical expansion of the disease and require special attention from health authorities. The objectives of the present study were to determine the prevalences of VL in a population of free-roaming dogs in an endemic region of Brazil, to establish the spatial distribution of infected dogs, and to examine the effectiveness of euthanasia of infected dogs in controlling the disease in this particular population. Dogs were captured every two months during seven sampling efforts. Capture locations were georeferenced and captured dogs were assessed for the presence of anti-Leishmania antibodies using an enzyme-linked immunosorbent assay (ELISA) as a screening test and the indirect fluorescent antibody test (IFAT) as the confirmatory procedure. Dogs that were seropositive by both assays were considered infected and were submitted to immediate euthanasia. After the end of the collection period, stored sera were evaluated with the Dual-Path Platform test (DPP). Animals positive by this method and by ELISA were also considered infected as currently recommended by the Brazilian Ministry of Health. Spatial analysis was performed using the Kernel technique. A total of 328 dogs were captured at least once during the sampling period, 25 (7.6%) of them were seropositive by ELISA and IFAT and 27 (8.2%) by DPP and ELISA. The prevalence of VL showed an overall decreasing trend. However, even with periodical euthanasia, it was not possible to eliminate the infection and increased prevalences were observed in the fourth and seventh samplings. There was a high overall agreement between the two criteria for defining infection. None of the dogs that tested negative by IFAT at the first capture seroconverted in the subsequent captures but a number of dogs exhibited changes in serological status over time. From the three dogs initially tested negative by ELISA and IFAT, but tested positive by the protocol currently adopted in Brazil, two became negative in subsequent recaptures. Spatial analysis revealed that infected animals concentrated in areas with a high density of free-roaming dogs. The existence of VL among homeless dogs may contribute significantly in the persistence of the disease among the human population, despite the practice of periodical euthanasia. The operational and ethical implications associated with euthanasia of free-roaming dogs, and the failure to control the transmission of VL among this particular population, led us to conclude that interventions promoting responsible ownership of pets may be a more effective strategy.

Autochthonous case of Canine Visceral Leishmaniasis in a non-endemic area in Minas Gerais, Brazil / Caso autóctone de Leishmaniose Visceral Canina em área indene em Minas Gerais

Visceral Leishmaniasis by Leishmania infantum chagasi is an endemic zoonosis present in many areas of Brazil. This parasite needs reservoirs for maintenance of the infection and the presence of dogs in urban areas is a key factor for the spread of canine visceral leishmaniasis (CVL). The aim of this study was to report the first autochthonous case of CVL in the municipality of Iguatama, in west central region of Minas Gerais State. Dog infection by Leishmania infantum chagasi was confirmed in the municipality, previously considered as non-endemic area to CVL. The canine infection by Leishmania was confirmed by three immunological tests for antibodies: indirect immunofluorescence assay (IFA), rapid Dual Path Platform (DPP®) CVL immunochromatographic test, enzyme-linked immunosorbent assay (ELISA), and microscopic demonstration of Leishmania amastigotes in imprints of spleen and bone marrow stained by Giemsa. The species Leishmania infantum chagasi was confirmed by molecular diagnosis (PCR). Studies are being carried out, aiming to describe the importance and the prevalence of this disease in the region and factors associated with its transmission.(AU)

Leishmaniose visceral causada por Leishmania infantum chagasi é uma zoonose endêmica em algumas regiões do Brasil. Este parasito necessita de reservatórios para a manutenção da infecção e a presença de cães em áreas urbanas é um fator importante para a manutenção e expansão da leishmaniose visceral canina (LVC). O objetivo deste estudo foi relatar o primeiro caso autóctone de LVC no município de Iguatama, na região Centro Oeste de Minas Gerais, cidade onde a LVC era tida como não existente. A infecção canina por Leishmania foi confirmada por três testes imunológicos para pesquisa de anticorpos: reação de imunofluorescência indireta (RIFI), teste rápido de imunocromatografia com plataforma dupla (DPP® LVC) e ensaio imunoenzimático (ELISA), e demonstração microscópica de amastigotas de Leishmania a partir de aposições de amostras de baço e de medula óssea corados pelo Giemsa. A espécie Leishmania infantum chagasi foi confirmada por diagnóstico molecular (PCR). Estudos estão sendo realizados com o objetivo de descrever a importância e a prevalência desta parasitose na região e os fatores associados com a transmissão.(AU)

Wild, synanthropic and domestic hosts of Leishmania in an endemic area of cutaneous leishmaniasis in Minas Gerais State, Brazil.

Domestic, synanthropic and wild hosts of Leishmania spp. parasites were studied in an area endemic for American tegumentary leishmaniasis (ATL), specifically in northern Minas Gerais State, Brazil. Domestic dogs and small forest mammals are reservoir hosts for L. (Leishmania) infantum. However, the role that these animals play in the transmission cycle of the Leishmania spp. that cause cutaneous leishmaniasis is not well known. This study evaluated 72 rodents, 25 marsupials and 98 domestic dogs found in two villages of the Xakriabá Indigenous Territory, an area of intense ATL transmission. A total of 23 dogs (23.47%) were shown to be positive according to at least one test; 8 dogs (8.16%) tested positive in a single serological test and 15 dogs (15.31%) tested positive by IFAT and ELISA. Eleven dogs were euthanised to allow for molecular diagnosis, of which nine (81.8%) tested positive by PCR for Leishmania in at least one tissue. Seven animals were infected only with L. (L.) infantum, whilst two displayed a mixed infection of L. (L.) infantum and L. (V.) braziliensis. Isoenzymatic characterisation identified L. (L.) infantum parasites isolated from the bone marrow of two dogs. Of the 97 small mammals captured, 24 tested positive for Leishmania by PCR. The results showed that L. (V.) braziliensis, L. (L.) infantum and L. (V.) guyanensis are circulating among wild and synanthropic mammals present in the Xakriabá Reserve, highlighting the epidemiological diversity of ATL in this region.