Neotropical wild rodents Akodon and Oligoryzomys (Cricetidae: Sigmodontinae) as important carriers of pathogenic renal Leptospira in the Atlantic forest, in Brazil.

Leptospirosis is an important worldwide zoonosis, caused by a bacterium of the genus Leptospira. For a better understanding of the disease, it is relevant the application of the one health concept. The Atlantic Forest is considered a biodiversity hotspot, with a great endemism of species and despite its importance and proximity to urban areas, the potential role of its fauna as carriers of infectious agents is still poorly understood. Although it is well-known that rats and mice are key reservoirs of leptospires, particularly Rattus norvegicus, wild rodents have also been revealed as reservoirs of leptospiral strains. Thus, the purpose of this study was to investigate the role of the sigmodontine rodents from genera Akodon and Oligoryzomys as pathogenic Leptospira carriers in the Atlantic Forest. We studied 52 Akodon spp. and 15 Oligoryzomys spp. from three areas. Overall 30% were PCR-positive for pathogenic Leptospira, 27% (14/52) Akodon spp. and 40% (6/15) Oligoryzomys spp. DNA sequencing of LipL32 gene confirmed nine species as pathogenic Leptospira. This remarkable incidence of leptospiral carriage within wild genera emphasizes the role of these rodents as carriers of leptospires throughout in this environment.

Pathogenic Leptospira species are widely disseminated among small mammals in Atlantic Forest biome.

Leptospirosis is a common worldwide bacterial zoonosis and has been studied in One Health approaches. Small mammals are described as the most important maintenance reservoirs of several pathogens in nature, including leptospires. The aim of this study was to identify infection by leptospires among small mammals on the Atlantic forest biome and evaluate their potential as carriers of these spirochetes. A total of 153 small mammals belonging to orders Rodentia and Didelphimorphia (distributed on 17 genera and 22 species) were captured. Blood and kidney samples were collected from animals and a conventional PCR targeted on lipL32 gene was conducted on renal tissues. Species identification was performed in eight samples by sequencing of rrs gene. A total of 28% of the animals presented lipL32 PCR-positive, and four pathogenic Leptospira species (L. interrogans, L. borgpetersenii, L. santarosai and L. noguchii) were identified. This study highlights the role of small mammals as carriers of leptospires on the Atlantic Forest representing a potential source of pathogenic Leptospira spp infection for both humans and domestic animals.

A systematic review of leptospirosis on wild animals in Latin America.

Leptospirosis is a bacterial systemic infection which affects domestic animals and wildlife, as well as humans. Many wild animals act as reservoirs of leptospires. Nevertheless, the real role of wildlife animals as source of infection to livestock and humans, as well as the most important reservoirs and leptospiral strains remains unclear. This systematic review assesses the available data about wildlife and their biomes in Latin America, concerning to leptospiral infection. In addition, we discuss the development of the research on leptospirosis in wildlife in this region. After the application of exclusion criteria, 79 papers were analyzed, comprising 186 species, 122 genus, 53 families, and 19 orders from four classes. Mammals were the most studied class, followed by Amphibian, Reptile, and Aves. The Icterohaemorrhagiae serogroup was predominant in most biomes and many orders. A small number of antigens detected the majority of seroreactive animals of each class, and a smaller panel may be used at microscopic agglutination test. Further studies must always consider edaphoclimatic conditions besides only host class or species, in order to obtain a broader understanding of the wild epidemiological cycle of leptospirosis in the region. In conclusion, direct and indirect evidences demonstrate that leptospirosis is largely widespread among wildlife in all biomes of Latin America. Moreover, more research on the role of wildlife on the epidemiology of leptospirosis and its impact on livestock and public health are required, particularly focusing on direct detection of the agent.

Leptospirosis on captive wild animals in Latin America.

Leptospirosis is a worldwide bacterial infection, being more prevalent in tropical regions. Human beings, domestic animals and wildlife species are susceptible to a wide variety of serovars. Zoos have a great importance in keeping endangered species, increasing populations and accumulating knowledge on these species. Although some studies describe the occurrence of leptospirosis in captivity animals, a systematic review regarding the infection in these animals in tropical areas has never been conducted. Thus, the objective of this study was to systematically gather and analyze data regarding leptospirosis among captive wild animals in Latin America. A total of 141 species were studied, 93 genus, 44 families and 15 orders from three classes. Median seroprevalence ranged from 0 to 52% and predominant serogroups were Canicola and Icterohaemorrhagiae for mammalian, and Sejroe for reptiles. One important outcome is that, when kept on zoos, wildlife is more frequently infected by incidental strains instead of adapted strains. Preventive measures should consider periodic serosurvey of all animal species in captivity, as well as the use of commercial vaccines to reduce leptospiral infection and its hazards.

Detection of wild animals as carriers of Leptospira by PCR in the Pantanal biome, Brazil.

Leptospiral infection is widespread in wildlife. In this context, wild ecosystems in tropical countries hold a vast biodiversity, including several species that may act as potential reservoirs of leptospires. The Pantanal biome presents highly favorable environmental conditions for the occurrence of leptospirosis, such as high temperatures, constant flooding, and high biodiversity. The purpose of this study was to detect wild animals as carriers of Leptospira sp. using direct methods (PCR and culture) in the Pantanal biome, Brazil. A total of 35 animals were studied, namely Cerdocyon thous, Nasua nasua, Ozotoceros bezoarticus, and Sus scrofa species. Blood for serology (MAT) and urine for bacteriological culturing and PCR was sampled. The most prevalent serogroups were Javanica and Djasiman. Additionally, 40.6% of these animals presented PCR positive reactions. Seroreactivity associated with the high frequency of leptospiral carriers among the different studied species suggests a high level of exposure of the studied animals to pathogenic Leptospira strains. Our results are still limited and the actual role of the studied animals in the epidemiology of leptospirosis in the Pantanal region remains to be elucidated.

[Comparison of nested-PCR with blood smear examination in detection of Ehrlichia canis and Anaplasma platys in dogs]. / Comparação de nested-PCR com o diagnóstico direto na detecçáo de Ehrlichia canis e Anaplasma platys em cães.

The clinical signs of Ehrlichia canis and Anaplasma platys infection are similar, and the diagnosis of these pathogens made by stained blood smears is poor due sensibility and specificity. On the other hand, the molecular diagnosis is highly sensitive and specific and nested-PCR have been optimized for accurate diagnosis these pathogens in dogs. At the veterinary teaching hospital, whole-blood samples with EDTA were obtained from 100 dogs and smears were made from blood samples for evaluation for intracellular parasites. For each sample, DNA was extracted and submitted to nPCR analysis for detection of E. canis and A. platys. The results of stained blood smears showed 9% of the animals were positive for E. canis and 21% for A. platys. Regarding of nPCR analysis, 57 and 55% of dogs were positive for E. canis and A. platys respectively. As compared to a nested PCR, the stained blood smears revealed false-negative results for both E. canis and A. platys. The results indicate that the nPCR is highly sensitive and specific for detection of both pathogens and the molecular diagnosis could be more useful at veterinary hospital.

Comparação de nested-PCR com o diagnóstico direto na detecção de Ehrlichia canis e Anaplasma platys em cães / Comparison of nested-PCR with blood smear examination in detection of Ehrlichia canis and Anaplasma platys in dogs

Os sinais clínicos das infecções por Ehrlichia canis e Anaplasma platys são similares, e o diagnóstico desses patógenos feito por esfregaços sanguíneos corados é difícil devido à sensibilidade e especificidade. Por outro lado, os diagnósticos moleculares são altamente sensíveis e específicos, e nested-PCRs têm sido otimizadas para o diagnóstico preciso desses patógenos em cães. Em um Hospital Veterinário Escola, amostras de sangue total com EDTA foram obtidas de 100 cães, e esfregaços foram feitos das amostras de sangue para busca dos parasitos intracelulares. Para cada amostra, DNA foi extraído e submetido à nPCR para detecção de E. canis e A. platys. Os resultados dos esfregaços sanguíneos mostraram que 9% dos animais foram positivos para E. canis e 21% para A. platys. Com relação à nPCR, 57 e 55% dos cães foram positivos para E. canis e A. platys, respectivamente. Quando comparados com a nPCR, os esfregaços sanguíneos corados revelaram resultados falso-negativos para E. canis e A. platys. Os resultados indicam que a nPCR é altamente sensível e específica para detecção de ambos os patógenos, e os diagnósticos moleculares podem ser mais úteis nos Hospitais Veterinários.

The clinical signs of Ehrlichia canis and Anaplasma platys infection are similar, and the diagnosis of these pathogens made by stained blood smears is poor due sensibility and specificity. On the other hand, the molecular diagnosis is highly sensitive and specific and nested-PCR have been optimized for accurate diagnosis these pathogens in dogs. At the veterinary teaching hospital, whole-blood samples with EDTA were obtained from 100 dogs and smears were made from blood samples for evaluation for intracellular parasites. For each sample, DNA was extracted and submitted to nPCR analysis for detection of E. canis and A. platys. The results of stained blood smears showed 9% of the animals were positive for E. canis and 21% for A. platys. Regarding of nPCR analysis, 57 and 55% of dogs were positive for E. canis and A. platys respectively. As compared to a nested PCR, the stained blood smears revealed false-negative results for both E. canis and A. platys. The results indicate that the nPCR is highly sensitive and specific for detection of both pathogens and the molecular diagnosis could be more useful at veterinary hospital.