Leishmania in synanthropic rodents (Rattus rattus): new evidence for the urbanization of Leishmania (Leishmania) amazonensis / Leishmania em roedores sinantrópicos (Rattus rattus): uma nova evidência da urbanização de Leishmania (Leishmania) amazonensis

Abstract This study aimed to detect parasites from Leishmania genus, to determine the prevalence of anti-Leishmania spp. antibodies, to identify circulating species of the parasite, and to determine epidemiological variables associated with infection in rats caught in urban area of Londrina, Paraná, Brazil. Animal capture was carried out from May to December 2006, serological and molecular methods were performed. DNA was extracted from total blood, and nested-PCR, targeting SSu rRNA from Leishmania genus, was performed in triplicate. The positive samples were sequenced twice by Sanger method to species determination. In total, 181 rodents were captured, all were identified as Rattus rattus and none showed clinical alterations. Forty-one of the 176 (23.3%) animals were positive for Leishmania by ELISA and 6/181 (3.3%) were positive by IFAT. Nine of 127 tested animals (7.1%) were positive by PCR; seven were identified as L. (L.) amazonensis, one as L. (L.) infantum. Four rats were positive using more than one test. This was the first description of synanthropic rodents naturally infected by L. (L.) amazonensis (in the world) and by L. (L.) infantum (in South Brazil). Regarding L. (L.) amazonensis, this finding provides new evidence of the urbanization of this etiological agent.

Resumo Esse estudo objetivou detectar parasitos do gênero Leishmania, determinar a prevalência de anticorpos anti-Leishmania spp., identificar as espécies circulantes do parasito e determinar variáveis epidemiológicas associadas com a infecção em ratos capturados em área urbana de Londrina, Paraná, Brazil. A captura dos animais ocorreu de maio a dezembro de 2006, métodos sorológicos e moleculares foram realizados. O DNA foi extraído do sangue total, uma nested-PCR cujo alvo foi o gene SSu rRNA do gênero Leishmania, foi realizado em triplicata. As amostras positivas foram sequenciadas duas vezes pelo método de Sanger para a determinação da espécie. No total, 181 roedores foram capturados, todos foram identificados como Rattus rattus e nenhum apresentou alterações clínicas. Quarenta e um dos 176 (23,3%) animais foram positivos no ELISA para Leishmania e 6/181 (3,3%) foram positivos na RIFI. Nove dos 127 animais testados (7,1%) foram positivos na PCR; sete foram identificadas como L. (L.) amazonensis, um como L. (L.) infantum. Quatro ratos foram positivos em mais de um teste. Essa é a primeira descrição de roedores sinantrópicos naturalmente infectados por L. (L.) amazonensis (no mundo) e por L. (L.) infantum (no Sul do Brasil). Com relação a L. (L.) amazonensis, esse resultado é uma nova evidência da urbanização desse agente etiológico.

Leishmania in synanthropic rodents (Rattus rattus): new evidence for the urbanization of Leishmania (Leishmania) amazonensis.

This study aimed to detect parasites from Leishmania genus, to determine the prevalence of anti-Leishmania spp. antibodies, to identify circulating species of the parasite, and to determine epidemiological variables associated with infection in rats caught in urban area of Londrina, Paraná, Brazil. Animal capture was carried out from May to December 2006, serological and molecular methods were performed. DNA was extracted from total blood, and nested-PCR, targeting SSu rRNA from Leishmania genus, was performed in triplicate. The positive samples were sequenced twice by Sanger method to species determination. In total, 181 rodents were captured, all were identified as Rattus rattus and none showed clinical alterations. Forty-one of the 176 (23.3%) animals were positive for Leishmania by ELISA and 6/181 (3.3%) were positive by IFAT. Nine of 127 tested animals (7.1%) were positive by PCR; seven were identified as L. (L.) amazonensis, one as L. (L.) infantum. Four rats were positive using more than one test. This was the first description of synanthropic rodents naturally infected by L. (L.) amazonensis (in the world) and by L. (L.) infantum (in South Brazil). Regarding L. (L.) amazonensis, this finding provides new evidence of the urbanization of this etiological agent.

Topical and Intradermal Efficacy of Photodynamic Therapy with Methylene Blue and Light-Emitting Diode in the Treatment of Cutaneous Leishmaniasis Caused by Leishmania braziliensis.

INTRODUCTION: The topical and intradermal photodynamic therapy (PDT) effect of methylene blue (MB) using light-emitting diode (LED) as light source (MB/LED-PDT) in the treatment of lesions of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis in hamsters were investigated. METHODS: Hamsters were infected in the footpad with 4×10(7) promastigotes of L. braziliensis and divided in 4 groups: Control group was not treated, AmB group was treated with amphotericin B, MB-Id group received intradermal MB at the edge of the lesion and MB-Tp group received MB topic. After treatment with MB, the animals were illuminated using red LEDs at the 655 nm wavelength for 1 hour. The MB/LED-PDT was carried out three times a week for 12 weeks. RESULTS: Animals of MB-Tp group presented lesion healing with significant diminution in extent of the lesion, and reduced parasite burden compared to control group; however, no significant difference was seen compared to the AmB group. MB-Tp group also showed reconstitution of the epithelium, the formation of collagen fibers, organization in the epidermis, a little disorganization and inflammation in the dermis. MB-Id was ineffective in all parameters evaluated, and it was comparable to the control group results. CONCLUSION: These data show that PDT with the use of MB-Tp and LED may be an alternative for the treatment of ACL. However, additional studies are being conducted to assess the potential of MB/LED-PDT, alone or in combination with conventional therapy, for the treatment of ACL.

Paracoccidioides brasiliensis Infection in Small Wild Mammals.

Paracoccidioidomycosis (PCM) is a systemic mycosis prevalent in Brazil and other Latin American countries. The etiological agents of PCM are the thermo-dimorphic fungi Paracoccidioides brasiliensis and P. lutzii. Taking into account that the natural habitat of Paracoccidioides spp. is still undefined, domestic and wild animals could be useful as indicators of Paracoccidioides spp. presence in endemic areas. The objective of this study was to evaluate the infection of small wild mammals by P. brasiliensis in an endemic area for human PCM. Samples from 38 wild mammals from different species such as Akodon sp., Thaptomys nigrita, Euryoryzomys russatus, Oligoryzomys nigripes, Monodelphis sp., Sooretamys angouya, Abrawayaomys angouya, Abrawayaomys ruschii and Akodontinae sp. were evaluated by ELISA, immunodiffusion, histopathology, nested PCR and culture. The overall positivity to gp43 observed in the ELISA was 23.7%. Samples from heart and liver of one O. nigripes were PCR positive, and the animal was also seropositive to gp43 in ELISA. This study showed that wild animals living in endemic areas for PCM are infected with P. brasiliensis and can be valuable epidemiological markers of the fungus presence in the environment. This is the first evidence of PCM infection in Akodon sp., E. russatus, T. nigrita and O. nigripes.

Detection of antibodies against Paracoccidioides brasiliensis in free-range domestic pigs (Sus scrofa).

Paracoccidioidomycosis, caused by the thermodimorphic fungus Paracoccidioides brasiliensis, is a human systemic mycosis prevalent in Latin America. Paracoccidioidomycosis affects mainly male rural workers, causing granulomatous lesions in several organs such as the lungs, liver and spleen. The participation of other animal species in the fungus epidemiology is not well understood. The objective of this study was to evaluate the infection of free-range domestic pigs by P. brasiliensis. Serum samples from 106 pigs were analyzed by ELISA and the immunodiffusion test, using P. brasiliensis gp43 and exoantigen as antigens, respectively. The overall positivity to gp43 in ELISA was 37.7 %, although no reactivity was observed in the immunodiffusion test and nor was P. brasiliensis detected in tissue samples (spleen, lung, liver and lymph nodes) from slaughtered animals submitted to culture, histopathological examination and PCR analysis. Five pigs seronegative to gp43 were exposed to natural infection by P. brasiliensis, and all animals seroconverted 3 months after exposure. The results suggest that free-range pigs are frequently infected with P. brasiliensis but are resistant to disease development. This is the first report of paracoccidioidomycosis in pigs.

Paracoccidioides brasiliensis infection in domestic rabbits (Oryctolagus cuniculus).

The objective of this study was to evaluate the infection of domestic rabbits by Paracoccidioides brasiliensis. Initially two rabbits were experimentally infected with P. brasiliensis and the humoral immune response was evaluated by ELISA using gp43 as antigen. The two animals showed IgG response against gp43 although no signs of disease were observed. The seroepidemiological study was carried out in 170 rabbits (free range n = 81 and caged n = 89) living in an endemic area for human paracoccidioidomycosis and a positivity of 27% was observed in the ELISA using gp43 as antigen. The free-range rabbits showed a significantly higher positivity (34.6-51.7%) than the caged animals (11.1%). Sentinel rabbits exposed to natural infection with P. brasiliensis were followed up for 6 months and a seroconversion rate of 83.3% was observed. This is the first report of paracoccidioidomycosis in rabbits and suggests that this species can be useful sentinels for P. brasiliensis presence in the environment.