Banca de DEFESA: ALESSANDRA SALLES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ALESSANDRA SALLES DA SILVA
DATE: 18/05/2023
TIME: 08:30
LOCAL: Google Meet
TITLE:

Clinical-epidemiological study of Leishmaniasp infection in a dog shelter in an endemic area of visceral leishmaniasis in the metropolitan region of Natal, Rio Grande do Norte

KEY WORDS:

Canine visceral leishmaniasis; Ehrliquia canis; Babesia canis; neglected tropical disease; public health; environmental health.

PAGES: 103
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

Visceral leishmaniasis (VL) occurs as a chronic infectious anthropozoonosis with worldwide distribution. Most cases of human VL occur in Brazil, East Africa and India with 50,000 to 90,000 new cases annually. In 2020 more than 90% of new cases were reported in Brazil, China, Ethiopia, Eritrea, India, Kenya, Somalia, Sudan, South Sudan and Yemen. VL is considered an urban and public health problem associated with socio-environmental vulnerability. The domestic dog is the main animal reservoir of Leishmania infantum since it makes the correlation between rural and urban spaces and lives in public spaces and homes. The sand fly Lutzomyia longipalpis is the vector of L. infantum. In order to take care of abandoned dogs, several countries have shelters. In Brazil, many emerged in a disorganized way, overcrowded and with risks of contamination of infectious and contagious diseases among individuals. The study aimed to analyze and describe the clinical and epidemiological scenario of VL in the metropolitan region of Natal, with a view to understanding the role of these shelters in the expansion or maintenance of VL, as well as infection by other pathogens. Initially, qualitative information was obtained from the shelter and it was found that the animals were examined for VL according to the Ministry of Health guidelines (Snap and ELISA tests) and treated according to clinical signs. In our study, 98 dogs were evaluated and physical-clinical examinations, blood collection and medullary aspirate were performed. Venous puncture was performed in the cephalic, femoral or jugular veins and between 3 and 5mL were collected from each animal. L. infantum infection was confirmed by enzyme-linked immunosorbent assay (ELISA) and anti-Leishmania antibody levels determined with soluble Leishmania antigens (SLA). The cutoff point was 0.392, this value was determined based on the average of the serum results of 6 healthy animals from an area not endemic for canine VL. Bone marrow aspirate for the presence of Leishmania was used in minimal essential culture medium (MANEM) containing 10% inactivated fetal bovine serum and hemin (8 µM). The search for the parasite in each culture/aspirate was performed on alternate days by optical microscopy up to 30 days after collection. Positive isolates for Leishmania by quantitative PCR (Qiagen extraction kit) were typed with specific primers for L. infantum. Oq-PCR was also used for Ehrlichia canis and Babesia canis (SYBR green reagent -Invitrogen, Grand Island, NY, USA). The DNA concentration for each sample was estimated by spectrophotometry at 260 nm. An estimate of the parasite burden in bone marrow aspirates was obtained by amplification of kinetoplast DNA (k-DNA) and MAG-1 with primers and probes described above. For DNA from E. canis eB. canis, SYBR green reagent primers (Invitrogen, Grand Island, NY, USA) were used with initial denaturation at 95°C for 10 minutes, followed by 40 cycles of amplification (95°C for 15 seconds and 60°C for 60 seconds in a Quantstudio thermal cycler 3 qPCR (Thermo-Fisher, Waltham, Massachusetts, USA). Sandflies were captured with CDC light traps installed between 6 pm and 6 am between April and December 2022, at two points in the shelter and two points in a forest fragment, on a property Pearson and Fisher chi-square tests and a generalized linear model (GLM) were used for statistical analysis to infer some associations. The presence of anti-Leishmania antibodies was estimated by the optical density (OD) of the ELISA using SLA and the results were used in statistics. Of the 98 dogs, 70% came from Parnamirim, followed by Natal, São Gonçalo do Amarante, Nísia Floresta and Macaíba. The predominant age group was greater than seven years. The most frequent signs were lesions on the skin, onychogryphosis and conjunctivitis. The q-PCR revealed 19% of dogs positive for L. infantum, 22% for E. canis and 18% for B. canis. The relationship between pathogens and deaths was significant for L. infantum MAG1 (P< 0.01) and Ehrlichia (P = 0.04). For dogs positive for MAG1, the chance of death increases by a factor of 4.56, whereas if they are positive for Ehrlichia canisa, the chance of death is around 2.75. No association between Babesia infection and death was found. L. longipalpis was the dominant species, being more frequent in the dog shelter (96%) followed by a chicken coop on private property. Molecular diagnosis is accurate in detecting Leishmania and has high sensitivity. The qPCR, considered the gold standard, to quantify the parasite load, can be used for the diagnosis and monitoring of dogs undergoing treatment. Our data show a correlation between the presence of DNA and antibody levels. Finally, the lack of population control and the abandonment of dogs can cause health, social and environmental disorders in underdeveloped countries or regions. The instability of ecosystems, high density of animals and infectious diseases.

COMMITTEE MEMBERS:
Presidente - 350500 - MARIA DE FATIMA FREIRE DE MELO XIMENES
Interno - 1062272 - JULIO ALEJANDRO NAVONI
Externo à Instituição - FILIPE DANTAS TORRES - Fiocruz - PE