Can domestic dogs be considered a good reservoir of Leishmania (L.) infantum chagasi in an endemic area of nonulcerated cutaneous leishmaniasis in Southern Honduras?

Dogs are considered to be the main domestic reservoir associated with the transmission of Leishmania (L.) infantum chagasi to humans in endemic areas of visceral leishmaniasis in America. However, little is known about the role of canines as a source of infection in endemic areas of nonulcerated cutaneous leishmaniasis (NUCL). Therefore, the objective of the present study was to investigate the role of dogs as a possible reservoir of the parasite in Southern Honduras. Dogs (n = 107) living with individuals affected by NUCL were clinically examined and biological material was collected for parasitological and immunological diagnosis. Most animals showed a healthy appearance and a few presented slight weight loss (64%), alopecia (7%), onychogryphosis (5%) and skin lesions (1%). The overall seroprevalence of Leishmania infection based on the DDP ® quick test and/or in-house ELISA serological test was 41%. The presence of the parasite's DNA was confirmed in 94% of the dogs; however, the average parasite load in the buffy coat was low at 6.09 parasites/µL, ranging between 0.221 and 50.2. The skin of seropositive dogs examined by histopathology using paraffin sections stained by hematoxylin and immunohistochemistry did not show cutaneous lesions or parasite amastigotes. Based on the absence of parasites in the skin and the low parasite load detected in the buffy coat, it seems that the dog does not represent a good source of infection for the vector in the endemic area of NUCL transmission in Southern Honduras. Other domestic and/or wild animals should be investigated.

Can domestic dogs be considered a good reservoir of Leishmania (L.) infantum chagasi in an endemic area of nonulcerated cutaneous leishmaniasis in Southern Honduras?

ABSTRACT Dogs are considered to be the main domestic reservoir associated with the transmission of Leishmania (L.) infantum chagasi to humans in endemic areas of visceral leishmaniasis in America. However, little is known about the role of canines as a source of infection in endemic areas of nonulcerated cutaneous leishmaniasis (NUCL). Therefore, the objective of the present study was to investigate the role of dogs as a possible reservoir of the parasite in Southern Honduras. Dogs (n = 107) living with individuals affected by NUCL were clinically examined and biological material was collected for parasitological and immunological diagnosis. Most animals showed a healthy appearance and a few presented slight weight loss (64%), alopecia (7%), onychogryphosis (5%) and skin lesions (1%). The overall seroprevalence of Leishmania infection based on the DDP ® quick test and/or in-house ELISA serological test was 41%. The presence of the parasite's DNA was confirmed in 94% of the dogs; however, the average parasite load in the buffy coat was low at 6.09 parasites/µL, ranging between 0.221 and 50.2. The skin of seropositive dogs examined by histopathology using paraffin sections stained by hematoxylin and immunohistochemistry did not show cutaneous lesions or parasite amastigotes. Based on the absence of parasites in the skin and the low parasite load detected in the buffy coat, it seems that the dog does not represent a good source of infection for the vector in the endemic area of NUCL transmission in Southern Honduras. Other domestic and/or wild animals should be investigated.

Immunohistochemical and Molecular Diagnosis of Mucocutaneous and Mucosal Leishmaniasis.

Leishmaniasis is a parasitic infection transmitted by the bite of infected female sandflies. It principally affects the skin, and the frequency of mucosal involvement is about 5% to 20%. Considering the rarity of leishmaniasis affecting the upper aerodigestive tract mucosa, we evaluated the characteristics of mucocutaneous leishmaniasis and mucosal leishmaniasis and the diagnostic difficulty when the parasites are scarce in tissue samples. The clinical, histopathological, histochemical, immunohistochemical, and molecular features of 17 cases of mucocutaneous leishmaniasis and mucosal leishmaniasis were assessed. Mucosal disease was principally found in the soft palate, oropharynx, and nose, manifesting mainly as a solitary ulcer. In hematoxylin and eosin-stained sections, 10 cases revealed abundant amastigotes within the macrophages. Giemsa staining was not shown to be helpful to confirm the diagnosis in 6 cases with scarce or nondetectable amastigotes. Immunohistochemistry (IHC) showed high sensitivity by positive staining in 14 out of 17 cases (82.3%). Polymerase chain reaction was shown to be more sensitive than IHC with 13 out of 14 (92.8%) positive cases, including the 3 IHC negative cases; however, this technique is not available in many endemic regions. In summary, we suggest that the IHC is a simple technique with rapid results and relatively low cost, when compared with other laboratorial procedures; thus, IHC is a helpful tool that should be implemented in the routine diagnosis of leishmania.

Canine antibody response to Lutzomyia longipalpis saliva in endemic area of visceral leishmaniasis.

INTRODUCTION: Canine exposure to Lutzomyia longipalpis bites and the potential of Leishmania infantum transmissibility for the vector were evaluated. METHODS: Immunoglobulin G (IgG) anti-Lu longipalpis saliva and -L. infantum, and blood parasite load were determined in dogs from endemic areas of visceral leishmaniasis. RESULTS: Blood parasitism was similar between symptomatic and asymptomatic dogs. IgG anti-L. infantum was higher in symptomatic dogs, but IgG anti-Lu. longipalpis saliva was mostly observed in higher titers in asymptomatic dogs, indicating vector preference for feeding on asymptomatic dogs. CONCLUSIONS: Our data suggest a pivotal role of asymptomatic dogs in L. infantum transmission in endemic areas.

Serological and infection statuses of dogs from a visceral leishmaniasis-endemic area.

OBJECTIVE: This study investigated the serological status of dogs living in a visceral leishmaniasis-endemic area and its correlation with the parasitological condition of the animals. METHODS: Canine humoral response was evaluated using the sera of 134 dogs by enzyme-linked immunosorbent assay and immunohistochemistry to detect parasites in the skin, lymph node, and spleen of the animals. The specific antibodies investigated were IgG, IgG1, IgG2, and IgE. RESULTS: According to the parasitological, laboratory, and clinical findings, the dogs were placed into one of four groups: asymptomatic with (AP+, n = 21) or without (AP-, n = 36) Leishmania tissue parasitism and symptomatic with (SP+, n = 52) or without (SP-, n = 25) parasitism. Higher IgG and IgE levels were positively correlated with the infection condition and parasite load, but not with the clinical status. In all groups, total IgG was the predominant antibody, which occurred at the expense of IgG2 instead of IgG1. Most of the infected dogs tested positive for IgG (SP+, 98.1%; AP+, 95.2%), whereas this was not observed with IgE (SP+, 80.8%; AP+, 71.2%). The most relevant finding was the high positivity of the uninfected dogs for Leishmania-specific IgG (SP-, 60.0%; AP-, 44.4%), IgE (SP-, 44.0%; AP-, 27.8%), IgG1 (SP-, 28.0%; AP-, 22.2%), and IgG2 antibodies (SP-, 56.0%; AP-, 41.7%). CONCLUSIONS: The serological status of dogs, as determined by any class or subclass of antibodies, did not accurately distinguish dogs infected with L. (L.) infantum chagasi from uninfected animals. The inaccuracy of the serological result may impair not only the diagnosis, but also epidemiological investigations and strategies for visceral leishmaniasis control. This complex serological scenario occurring in a visceral leishmaniasis-endemic area highlights the challenges associated with canine diagnosis and points out the difficulties experienced by veterinary clinicians and coordinators of control programs.

Serological and infection statuses of dogs from a visceral leishmaniasis-endemic area / Status sorológico e de infecção canina em área endêmica de leishmaniose visceral

OBJECTIVE This study investigated the serological status of dogs living in a visceral leishmaniasis-endemic area and its correlation with the parasitological condition of the animals. METHODS Canine humoral response was evaluated using the sera of 134 dogs by enzyme-linked immunosorbent assay and immunohistochemistry to detect parasites in the skin, lymph node, and spleen of the animals. The specific antibodies investigated were IgG, IgG1, IgG2, and IgE. RESULTS According to the parasitological, laboratory, and clinical findings, the dogs were placed into one of four groups: asymptomatic with (AP+, n = 21) or without (AP-, n = 36) Leishmania tissue parasitism and symptomatic with (SP+, n = 52) or without (SP-, n = 25) parasitism. Higher IgG and IgE levels were positively correlated with the infection condition and parasite load, but not with the clinical status. In all groups, total IgG was the predominant antibody, which occurred at the expense of IgG2 instead of IgG1. Most of the infected dogs tested positive for IgG (SP+, 98.1%; AP+, 95.2%), whereas this was not observed with IgE (SP+, 80.8%; AP+, 71.2%). The most relevant finding was the high positivity of the uninfected dogs for Leishmania-specific IgG (SP-, 60.0%; AP-, 44.4%), IgE (SP-, 44.0%; AP-, 27.8%), IgG1 (SP-, 28.0%; AP-, 22.2%), and IgG2 antibodies (SP-, 56.0%; AP-, 41.7%). CONCLUSIONS The serological status of dogs, as determined by any class or subclass of antibodies, did not accurately distinguish dogs infected with L. (L.) infantum chagasi from uninfected animals. The inaccuracy of the serological result may impair not only the diagnosis, but also epidemiological investigations and strategies for visceral leishmaniasis control. This complex serological scenario occurring in a visceral leishmaniasis-endemic area highlights the challenges associated with canine diagnosis and points out the difficulties experienced by veterinary clinicians and coordinators of ...

OBJETIVO Foi investigado o status sorológico de cães, em área endêmica de leishmaniose visceral, e sua correlação com a infecção parasitológica dos animais. MÉTODOS A resposta humoral canina foi avaliada no soro de 134 cães pelo método ELISA e pela imuno-histoquímica, para detectar parasitos na pele, linfonodo e baço desses animais. Os anticorpos específicos investigados foram IgG, IgG1, IgG2 e IgE. RESULTADOS De acordo com os achados parasitológicos, laboratoriais e clínicos, os cães foram alocados em um dos quatro grupos: assintomáticos com (AP+, n = 21) e sem (AP-, n = 36) parasitismo tecidual por Leishmania e sintomáticos com (SP+, n = 52) ou sem (SP-, n = 25) parasitismo. Níveis mais elevados de IgG e IgE se correlacionaram positivamente com o status de infecção e a carga parasitária, mas não com a condição clínica. Em todos os grupos, IgG total foi o anticorpo predominante, com maior concentração de IgG2 que IgG1. O anticorpo IgG foi positivo em proporção elevada nos animais infectados (SP+ 98,1%; AP+ 95,2%), mas não o IgE (SP+ 80,8%; AP+ 71,2%). O achado mais relevante refere-se aos cães não infectados que apresentaram elevada positividade para anticorpos IgG anti-Leishmania (SP- 60,0%; AP- 44,4%), IgE (SP- 44,0%; AP- 27,8%), IgG1 (SP- 28,0%; AP- 22,2%) e IgG2 (SP- 56,0%; AP- 41,7%). CONCLUSÕES O status sorológico dos cães, determinado por qualquer classe ou subclasse de anticorpos, não distinguiu com acurácia cães infectados por L. (L.) infantum chagasi daqueles não infectados. A imprecisão do resultado sorológico pode prejudicar não só o diagnóstico, mas também as investigações epidemiológicas e as estratégias para o controle da leishmaniose visceral. Esse complexo ...

Perfil de sensibilidade a drogas antifúngicas e tipagem molecular de isolados de Pichia anomala provenientes de pacientes com fungemia nosocomial / Susceptibility profile to antifungal drugs and molecular typing of Pichia anomala isolated from patients presenting nosocomial fungemia

Nos últimos anos, as infecções fúngicas têm se caracterizado pelo seu aumento em freqüência e gravidade das infecções, bem como pela diversidade dos fungos isolados. Candida spp representa o quarto grupo de patógenos nosocomiais mais comumente isolados no sangue, porém fungemias causadas por Pichia anomala têm sido descritas com relativa freqüência. No presente estudo, 42 isolados de P. anomala de hemocultura foram analisados. /In the last years, fungal infections have been characterized by increased frequency and gravity of the infections, as well as for the diversity of isolated fungi. Candida spp represents the fourth group of nosocomial pathogens more frequently isolated in peripheral blood. However, fungemias caused by Pichia anomala have been described with relative frequency. In the present study, 42 blood isolates of P. anomala were analyzed. Approximately 100 per cent of them showed susceptibility to fluconazole, voriconazole and amphotericin B, In respect to itraconazole, 32 per cent of the isolates were susceptible, 66 per cent, susceptible-dose dependent and 2 per cent, resistant to this antifungal drug. Electrophoretic karyotyping evidenced different types and subtypes among non- related isolates. Identical karyotype patterns were determined among sequential samples from the same patient and samples from an outbreak. This work presents the greatest number of P. anomala isolates already analyzed in respect to the yeast susceptibility to antifungal agents as well as it demonstrates that electrophoretic karyotyping ...