Aspectos epidemiológicos da leishmaniose visceral canina na zona rural do semiárido paraibano e análise de técnicas de diagnóstico

Abstract

ABSTRACT.-Silva R.B.S., Mendes R.S., Santana V.L., Souza H.C., Ramos C.P.S., Souza A.P., Andrade P. Visceral leishmaniasis is caused by Leishmania infantum in Brazil. It is a chronic disease and often a fatal zoonosis and considered as a serious worldwide public health problem and recognized by the World Health Organization as one of seventeen "Neglected Tropical Diseases". This study was conducted in 2012 in the county of Patos, in Paraíba State semiarid region. The main purposes were to estimate the prevalence and the risk factors of canine visceral leishmaniasis (CVL), and to evaluate the performance of serological tests. Serological prevalence was determined using three techniques (ELISA, IFA and DPP chromatographic immunoassay -Dual Path Platform). ELISA was the golden standard, since it is the confirmatory test for CVL as established by the Brazilian Ministry of Health. In total, 362 blood samples were collected and were considered positive if positive by two serological assays. Positive samples were tested by PCR and qPCR. An epidemiological questionnaire was applied to the dog owner to identify risk factors associated with CVL. The seroprevalence was 11.33% (41/362). Chromatographic immunoassay -DPP showed a sensitivity of 58% (95%, CI: 0.43 to 0.72) and specificity of 96% (95%, CI: 0.93-0.98) , with a Kappa index of 0.5. The IFA had a sensitivity of 85% (95%, CI: 0.72 to 0.94), specificity of 99% (95%, CI: 0.98 to 1) and Kappa value of 0.8. The risk factor identified in the multivariate analysis was gender (OR=2.15 [1.09 to 4.21]), male dogs having 2.15 times more chance of being infected. The increased likelihood can possibly be explained by the use of male dogs for hunting and as guard dogs, two factors that increase dog contact to infected sandflies. Due to the prevalence rates, it should be recommended control measures against canine visceral leishmaniasis. The results demonstrated that the Chromatographic immunoassay (DPP-Dual Path Platform) is not the best technique for screening positive animals due to its low sensitivity, suggesting its replacement by ELISA.

Evaluation of the euthanasia of seropositive dogs for canine visceral leishmaniasis as the only method of controling the disease in the enzootic area in the Midwestern Minas Gerais

“…Maintaining high serum CVL prevalence in the municipality of Iguatama, as found in this study, serves as a warning to health professionals and local authorities about the need for more efficient CVL control measures in the municipality. The prevalence of CVL in Iguatama today is similar to that found in the Paraíba semi-arid region of northeastern Brazil (Silva et al 2016), a geographical region with the highest prevalence of Human Visceral Leishmaniasis (HVL) and CVL in the country (Bavia et al 2005).…”

Improving the reference standard for the diagnosis of canine visceral leishmaniasis: a challenge for current and future tests

“… 37 Another more recent study used the direct parasitological test associated with the parasite culture, and it estimated sensitivity for TR-DPP of 100%; its specificity varied between 22 and 96%. 38 The study by Silva et al 39 used serological tests as a reference standard and the TR-DPP’s sensitivity was 58.33% (CI95% 43 to 72). Carvalho et al 10 demonstrated that by using qPCR in blood serum samples, the protocol for CVL diagnosis prescribed by the Ministry of Health had a sensitivity of 67.24% (CI95% 54.42 to 77.92) and specificity of 86.59% (CI95% 77.55 to 92.34).…”

Presença de Leishmania spp. na conjuntiva de um cão não reativo para testes parasitológicos em linfonodos e medula óssea – relato de caso

“…Sabe-se que o animal em estudo é oriundo de uma região onde a prevalência de leishmaniose é de 7,2% na zona urbana (PORTO, 2010) e 11,33% na zona rural (SILVA et al, 2016), chamando a atenção para a necessidade de se investigar animais que apresentem, além dos sinais clínicos mais comuns observados na leishmaniose, alterações no sítio ocular. Embora estudos relatem que os machos têm 2,15 vezes mais chances de apresentar a doença na região do semiárido paraibano (SILVA et al, 2016), constatou-se, no presente relato, que a paciente era fêmea, chamando-se a atenção para a necessidade de se investigar leishmaniose em machos e fêmeas com alterações oculares.…”

“…Embora estudos relatem que os machos têm 2,15 vezes mais chances de apresentar a doença na região do semiárido paraibano (SILVA et al, 2016), constatou-se, no presente relato, que a paciente era fêmea, chamando-se a atenção para a necessidade de se investigar leishmaniose em machos e fêmeas com alterações oculares. Em um estudo em que se avaliou 56 cães positivos para leishmaniose visceral, não houve diferença estatisticamente significativa entre machos e fêmeas (ALMEIDA; MENDONÇA; SOUSA, 2010), reforçando, assim, a necessidade de se pesquisar leishmaniose em qualquer animal.…”