Session Type: ePosters
Session Title: ePosters
Authors(s): M. Fernandes (1, 2), T. Carreira (1, 2), R. Teodósio (3, 2), M.L. Vieira (1, 2)
Authors Affiliations(s): (1) Laboratório de Leptospirose e Borreliose de Lyme, Unidade de Microbiologia Médica, Portugal, (2) Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Lisboa, Portugal, Portugal, (3) Unidade de Clínica Tropical, Portugal
Background:
Leptospirosis is one of the most widely distributed zoonosis worldwide. Humans (accidental hosts) are commonly infected upon direct or indirect contact with urine from animals colonized or infected with leptospires. Rodents are the main reservoirs for Leptospira spp. transmission, shedding leptospires in urine, which are mainly responsible for contaminating waters and soils.
Most cases of leptospirosis occur during months with increased rainfall, with several leptospirosis outbreaks often related to floods, when the spread of contaminated freshwater throughout the surrounding environment increases.
This study aimed to analyze the differences in the prevalence of Leptospira spp. in freshwaters of Lisbon and Setubal districts (Portugal), during the winter and summer seasons.
Methods:
A total of 313 freshwater samples were collected in the winter and summer seasons, of which 166 were obtained in winter and 147 in the summer season, at the same collection sites (e.g., lakes, ponds, rivers), in four and seven counties from Lisbon and Setubal districts, respectively. To determine possible differences in the prevalence of leptospiral DNA in freshwaters that could be related to the meteorological conditions, certain parameters were recorded in each moment of samples collection (during the winter and/or the summer seasons), such as the relative humidity, and air temperature, among others (e.g., sunny, rainy, cloudy).
After DNA extraction from all samples, two nested-PCR protocols with different primers were used. A first PCR protocol with universal primers based on rrs (16S) gene was applied, for Leptospira genus detection. Each sample with leptospiral DNA amplification, was then evaluated in a second PCR protocol, with specific primers (targeting lipL32 gene) for detection of pathogenic species.
Results:A higher prevalence of pathogenic Leptospira species in freshwaters during the summer season was observed, 60% (n=33+/55), compared with the winter results, 42% (n=39+/92), showing an association between the summer season and the presence of pathogenic leptospires in freshwaters. However, no association was found among the meteorological parameters observed in both seasons.
Conclusions:The impact of the seasonality on leptospires dissemination throughout freshwaters is evident, leading to a concern about the risk it poses for public health, namely the recreational activities that occur in the summer.
Keyword(s): Leptospira spp., Environment, Public HealthSession Type: ePosters
Session Title: ePosters
Authors(s): M. Fernandes (1, 2), T. Carreira (1, 2), R. Teodósio (3, 2), M.L. Vieira (1, 2)
Authors Affiliations(s): (1) Laboratório de Leptospirose e Borreliose de Lyme, Unidade de Microbiologia Médica, Portugal, (2) Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Lisboa, Portugal, Portugal, (3) Unidade de Clínica Tropical, Portugal
Background:
Leptospirosis is one of the most widely distributed zoonosis worldwide. Humans (accidental hosts) are commonly infected upon direct or indirect contact with urine from animals colonized or infected with leptospires. Rodents are the main reservoirs for Leptospira spp. transmission, shedding leptospires in urine, which are mainly responsible for contaminating waters and soils.
Most cases of leptospirosis occur during months with increased rainfall, with several leptospirosis outbreaks often related to floods, when the spread of contaminated freshwater throughout the surrounding environment increases.
This study aimed to analyze the differences in the prevalence of Leptospira spp. in freshwaters of Lisbon and Setubal districts (Portugal), during the winter and summer seasons.
Methods:
A total of 313 freshwater samples were collected in the winter and summer seasons, of which 166 were obtained in winter and 147 in the summer season, at the same collection sites (e.g., lakes, ponds, rivers), in four and seven counties from Lisbon and Setubal districts, respectively. To determine possible differences in the prevalence of leptospiral DNA in freshwaters that could be related to the meteorological conditions, certain parameters were recorded in each moment of samples collection (during the winter and/or the summer seasons), such as the relative humidity, and air temperature, among others (e.g., sunny, rainy, cloudy).
After DNA extraction from all samples, two nested-PCR protocols with different primers were used. A first PCR protocol with universal primers based on rrs (16S) gene was applied, for Leptospira genus detection. Each sample with leptospiral DNA amplification, was then evaluated in a second PCR protocol, with specific primers (targeting lipL32 gene) for detection of pathogenic species.
Results:A higher prevalence of pathogenic Leptospira species in freshwaters during the summer season was observed, 60% (n=33+/55), compared with the winter results, 42% (n=39+/92), showing an association between the summer season and the presence of pathogenic leptospires in freshwaters. However, no association was found among the meteorological parameters observed in both seasons.
Conclusions:The impact of the seasonality on leptospires dissemination throughout freshwaters is evident, leading to a concern about the risk it poses for public health, namely the recreational activities that occur in the summer.
Keyword(s): Leptospira spp., Environment, Public Health