Detection of Leishmania infantum in animals and their ectoparasites by conventional PCR and real time PCR.

Visceral leishmaniosis (VL) is a parasitic disease caused by Leishmania infantum, which is primarily transmitted by phlebotomine sandflies. However, there has been much speculation on the role of other arthropods in the transmission of VL. Thus, the aim of this study was to assess the presence of L. infantum in cats, dogs and their ectoparasites in a VL-endemic area in northeastern Brazil. DNA was extracted from blood samples and ectoparasites, tested by conventional PCR (cPCR) and quantitative real time PCR (qPCR) targeting the L. infantum kinetoplast DNA. A total of 280 blood samples (from five cats and 275 dogs) and 117 ectoparasites from dogs were collected. Animals were apparently healthy and not previously tested by serological or molecular diagnostic methods. Overall, 213 (76.1 %) animals and 51 (43.6 %) ectoparasites were positive to L. infantum, with mean parasite loads of 795.2, 31.9 and 9.1 fg in dogs, cats and ectoparasites, respectively. Concerning the positivity between dogs and their ectoparasites, 32 (15.3 %) positive dogs were parasitized by positive ectoparasites. The overall concordance between the PCR protocols used was 59.2 %, with qPCR being more efficient than cPCR; 34.1 % of all positive samples were exclusively positive by qPCR. The high number of positive animals and ectoparasites also indicates that they could serve as sentinels or indicators of the circulation of L. infantum in risk areas.

Clinical and epidemiological profiles of patients with American cutaneous leishmaniasis from the states of Pernambuco and Amazonas, Brazil.

INTRODUCTION: Brazil has a high number of cases of American cutaneous leishmaniasis (ACL) in the north and northeast regions. Therefore, continuous surveillance of environmental and socioeconomic factors in endemic areas is needed to develop strategic control measures. This study aimed to describe the clinical and epidemiological profiles of patients with ACL. METHODS: All patients were from the states of Amazonas and Pernambuco, and examinations were carried out between 2015 and 2018. All patients had a clinical and epidemiological history compatible with ACL after positive diagnostic tests. Information obtained from medical records included gender, employment activity, level of education, age, and number and sites of lesions. RESULTS: A total of 213 patients were included, of whom 30.98% were female and 69.02% were male. The main employment activity was agriculture (27.56%). The most common level of education was elementary (62.42%). The average age was approximately 39 years. The majority of the patients presented only with one lesion (54.87%), and legs/feet were the most commonly affected area (48.25%), followed by the arms/hands (44.75%). CONCLUSIONS: These data demonstrated that irrespective of the patients' places of origin, interventions need to be focused on men of economically productive age, in view of the high risk of exposure to the vector in this group. Education activities need to be directed to farmers about the importance of protection against ACL vectors during work. Such information must also be directed to employers as a way of implementing and maintaining appropriate working conditions and stepping up vector control.

Seroprevalence and spatial distribution of canine leishmaniasis in an endemic region in Brazil: how has the situation changed after 10 years?

INTRODUCTION: Herein, we assessed the seroprevalence and spatial distribution of Leishmania infantum in dogs in Garanhuns, Northeastern Brazil. METHODS: Sera samples (n = 242) were analyzed using an enzyme-linked immunosorbent assay (ELISA). The spatial distribution of dogs seropositive for anti-Leishmania infantum antibodies was evaluated using kernel density estimation. RESULTS: A total of 2.4% (6/242) of the animals were seropositive for anti-Leishmania infantum antibodies. The kernel map showed their distribution to be heterogeneous over the city, with a hotspot in the northeastern region. CONCLUSIONS: The reported data illustrate the circulation of parasites of the genus Leishmania in a canine population.

Clinical and epidemiological profiles of patients with American cutaneous leishmaniasis from the states of Pernambuco and Amazonas, Brazil

Abstract INTRODUCTION: Brazil has a high number of cases of American cutaneous leishmaniasis (ACL) in the north and northeast regions. Therefore, continuous surveillance of environmental and socioeconomic factors in endemic areas is needed to develop strategic control measures. This study aimed to describe the clinical and epidemiological profiles of patients with ACL. METHODS: All patients were from the states of Amazonas and Pernambuco, and examinations were carried out between 2015 and 2018. All patients had a clinical and epidemiological history compatible with ACL after positive diagnostic tests. Information obtained from medical records included gender, employment activity, level of education, age, and number and sites of lesions. RESULTS: A total of 213 patients were included, of whom 30.98% were female and 69.02% were male. The main employment activity was agriculture (27.56%). The most common level of education was elementary (62.42%). The average age was approximately 39 years. The majority of the patients presented only with one lesion (54.87%), and legs/feet were the most commonly affected area (48.25%), followed by the arms/hands (44.75%). CONCLUSIONS: These data demonstrated that irrespective of the patients' places of origin, interventions need to be focused on men of economically productive age, in view of the high risk of exposure to the vector in this group. Education activities need to be directed to farmers about the importance of protection against ACL vectors during work. Such information must also be directed to employers as a way of implementing and maintaining appropriate working conditions and stepping up vector control.

Seroprevalence and spatial distribution of canine leishmaniasis in an endemic region in Brazil: how has the situation changed after 10 years?

Abstract INTRODUCTION: Herein, we assessed the seroprevalence and spatial distribution of Leishmania infantum in dogs in Garanhuns, Northeastern Brazil. METHODS: Sera samples (n = 242) were analyzed using an enzyme-linked immunosorbent assay (ELISA). The spatial distribution of dogs seropositive for anti-Leishmania infantum antibodies was evaluated using kernel density estimation. RESULTS: A total of 2.4% (6/242) of the animals were seropositive for anti-Leishmania infantum antibodies. The kernel map showed their distribution to be heterogeneous over the city, with a hotspot in the northeastern region. CONCLUSIONS: The reported data illustrate the circulation of parasites of the genus Leishmania in a canine population.

Tracking false-negative results in molecular diagnosis: proposal of a triplex-PCR based method for leishmaniasis diagnosis

Molecular biological methods have become increasingly relevant to the diagnosis and control of infectious diseases, such as leishmaniasis. Since various factors may affect the sensitivity of PCR assays, including DNA yield and purity, an optimal extraction method is pivotal. Losses of a parasite’s DNA during extraction may significantly impair its detection by PCR and lead to false-negative results. This study proposes a triplex PCR assay targeting the parasite’s DNA, an external control (pUC18) and an internal control (G3PD) for accurate diagnosis of leishmaniasis.

Tracking false-negative results in molecular diagnosis: proposal of a triplex-PCR based method for leishmaniasis diagnosis

Molecular biological methods have become increasingly relevant to the diagnosis and control of infectious diseases, such as leishmaniasis. Since various factors may affect the sensitivity of PCR assays, including DNA yield and purity, an optimal extraction method is pivotal. Losses of a parasite’s DNA during extraction may significantly impair its detection by PCR and lead to false-negative results. This study proposes a triplex PCR assay targeting the parasite’s DNA, an external control (pUC18) and an internal control (G3PD) for accurate diagnosis of leishmaniasis.