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

Abstract

word count: 220 2 Manuscript word count: 3,574 ABSTRACT Background. Leptospirosis 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.Methods and findings. From 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. Conclusions.Strategies 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.Author Summary: To 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 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.

Leptospirosis in Si Sa Ket, Thailand: Incidence and Factors of Death during 2010-2019

“…Time: The incidence of leptospirosis was found throughout the year. It's often peak incidence between August to October in association with the rainy season and precipitation (Cunha et al, 2019 andDeshmukh et al, 2019). Flooding is known to promote leptospirosis transmission, which correlates with the amount of rainfall (Rahayu et al, 2018, Hinjoy, 2014, Carvajal and Fagerstrom, 2017and Santos et al, 2017.…”

Antibacterial activity of medicinal plants against Leptospira spp.: a literature review

“…The bacteria released through rodent urine is present in ponds, rivers, puddles, sewers, agricultural fields, wet soils, among others. The number of cases of leptospirosis related directly to the amount of rainfall, which makes this a seasonal pathology in temperate climates whereas a permanent disease present all year round in tropical climates (Cunha et al, 2019).…”