Biology subjects

Ribeiro, G. S.

Publications and source records attributed to Ribeiro, G. S..

3 recordsLinked to original sources

bioRxiv2024

Wolbachia introgression in Ae. aegypti is accompanied by variable loss - a multi-country assessment

The wMel and wAlbB strains of the bacterial endosymbiont Wolbachia are being introgressed into Aedes aegypti populations as a biocontrol method to reduce the transmission of medically important arboviruses. Successful introgression of Wolbachia relies on both persistence of Wolbachia throughout the host life cycle and a high fidelity of maternal transmission of Wolbachia between generations. wMel has been introgressed into field populations in 14 countries to date. Monitoring of field sites has shown that wMel prevalence can fluctuate substantially over time, prompting concerns this could lead to reduced efficacy of the biocontrol method. To explore the fidelity of wMel persistence and transmission, we developed molecular methods to measure the prevalence of Ae. aegypti negative for Wolbachia infection but carrying the "founder" mitochondrial haplotype of the single female first transinfected. As all released wMel-infected mosquitoes and any subsequent offspring will carry this founder mitochondrial haplotype, any mosquitoes with this mitochondrial haplotype and without wMel indicate that wMel was lost from this lineage at some point. We observed loss of wMel ranging from 0 to 20.4% measured at various time intervals after wMel-infected mosquito releases in five different countries. Despite some field sites showing Wolbachia loss, overall Wolbachia prevalence was sustained during the time periods studied. We then employed laboratory studies to explore factors that could contribute to the loss of wMel. Surprisingly, near-perfect maternal transmission was measured across laboratory conditions of early blood feeding, starvation, and salinity. Collectively, these findings underscore that although wMel transmission can be imperfect it does not necessarily undermine population-level establishment, providing encouragement that the intervention will be robust in most dengue-endemic environments.

ecology↗

bioRxiv2020

Reduced competence to arboviruses following the sustainable invasion of Wolbachia into native Aedes aegypti from Niteroi, Southeastern Brazil

Field release of Wolbachia-infected Aedes aegypti has emerged as a promising solution to manage the transmission of dengue, Zika and chikungunya in endemic areas across the globe. Through an efficient self-dispersing mechanism, and the ability to induce virus-blocking properties, Wolbachia offers an unmatched potential to gradually modify wild Ae. aegypti populations turning them unsuitable disease vectors. Here in this work, a proof-of-concept field trial was carried out in a small community of Niteroi, greater Rio de Janeiro. Following the release of Wolbachia-infected eggs, we reported a successful invasion and long-term establishment of the bacterium across the territory, as denoted by stable high-infection indexes (>80%). We have also demonstrated that refractoriness to dengue and Zika viruses, either thorough oral-feeding or intra-thoracic saliva challenging assays, were maintained over the adaptation to the natural environment of Southeastern Brazil. These findings further support Wolbachias ability to invade local Ae. aegypti populations and impair disease transmission, and shall pave the way for future epidemiological and economic impact assessments.

microbiology↗

bioRxiv2019

Rainfall and other meteorological factors as drivers of urban transmission of leptospirosis

BackgroundLeptospirosis is an important public health problem affecting vulnerable urban slum populations in developing country settings. However, the complex interaction of meteorological factors driving the temporal trends of leptospirosis remain incompletely understood.\n\nMethods and findingsFrom 1996 to 2010, we investigated the association between the weekly incidence of leptospirosis and climatic variables in the city of Salvador, Brazil by using a dynamic generalized linear model that accounted for time lags, overall trend and seasonal variation. Our model showed an increase of leptospirosis cases associated with rainfall, lower temperature and higher humidity. There was a lag of one-to-two weeks between weekly values for significant meteorological variables and leptospirosis incidence. Independent of the season, a weekly cumulative rainfall of 20 mm increased the risk of the leptospirosis by 10% compared to a week without rain. Finally, over the 14 year study period the incidence of leptospirosis decreased significantly by four fold (12.8 versus 3.6 per 100,000 people), independently of variations in climate.\n\nConclusionsStrategies to control leptospirosis should focus on avoiding contact with contaminated sources of Leptospira as well as on increasing awareness in the population and health professionals within the short time window after both low-level and extreme rainfall events. Increased leptospirosis incidence was restricted to one-to-two weeks after those events suggesting that infectious Leptospira survival may be limited to short time intervals.\n\nAuthor SummaryTo determine the role of meteorological variables, seasonal variation and temporal trends in the incidence of leptospirosis, we investigated the time series of leptospirosis incidence amongst residents of Salvador, Brazil, from 1996 to 2010. Exploratory and confirmatory statistical methods detected associations between meteorological factors and disease incidence. Results showed the importance of extreme meteorological conditions, particularly rainfall, as short-term predictors of leptospirosis incidence. In addition, we found a long-term decreasing trend of in disease incidence over the observation period.

epidemiology↗