Leptospirosis Outbreaks in Nicaragua: Identifying Critical Areas and Exploring Drivers for Evidence-Based Planning

Abstract

Leptospirosis is an epidemic-prone zoonotic disease that occurs worldwide. In Central America, leptospirosis outbreaks have been reported in almost all countries; Nicaragua in particular has faced several outbreaks. The objective of this study was to stratify the risk and identify “critical areas” for leptospirosis outbreaks in Nicaragua, and to perform an exploratory analysis of potential “drivers”. This ecological study includes the entire country (153 municipalities). Cases from 2004 to 2010 were obtained from the country’s health information system, demographic and socioeconomic variables from its Census, and environmental data from external sources. Criteria for risk stratification of leptospirosis were defined. Nicaragua reported 1,980 cases of leptospirosis during this period, with the highest percentage of cases (26.36%) in León, followed by Chinandega (15.35%). Among the 153 municipalities, 48 were considered critical areas, 85 were endemic and 20 silent. Using spatial and statistical analysis, the variable presenting the most evident pattern of association with critical areas defined by top quintile of incidence rate is the percentage of municipal surface occupied by the soil combination of cambisol (over pyroclastic and lava bedrock) and andosol (over a volcanic ashes foundation). Precipitation and percentage of rural population are also associated with critical areas. This methodology and findings could be used for Nicaragua’s Leptospirosis Intersectoral Plan, and to identify possible risk areas in other countries with similar drivers.

Socioeconomic Factors and Vulnerability to Outbreaks of Leptospirosis in Nicaragua

“…In addition, these departments together reported 1001 human cases that represented 50.6% of all cases of leptospirosis reported in Nicaragua between 2004 and 2010, time period of the previous study that identified the critical areas using the same database with country official information [4]. Chinandega and Leon have been identified by local experts and in the previous study as risk areas for having the highest incidence rates among all municipalities.…”

“…Urbanization and climate change can cause an increase in the frequency and intensity of these factors, consequently increasing the incidence of the disease and the occurrence of outbreaks [3]. Other studies have also found an association between soil types, particularly in relation to its ability to retain moisture, and the levels of proliferation of leptospira [4,7]. Alkaline and neutral soil types, especially of volcano origin, may facilitate longer survival of the bacteria [4,8].…”

“…Other studies have also found an association between soil types, particularly in relation to its ability to retain moisture, and the levels of proliferation of leptospira [4,7]. Alkaline and neutral soil types, especially of volcano origin, may facilitate longer survival of the bacteria [4,8]. …”

Leptospirosis Renal Disease: Emerging Culprit of Chronic Kidney Disease Unknown Etiology

“…For example, in Sri Lanka, where CKDu is highly prevalent in the central dry zone with paddy field, leptospirosis outbreaks were found notably in historic record, with the most recent ones in 2008 and 2011 [14,15]. Another example is the sugarcane fields in Chichigalpa, Chinandega in Nicaragua, a focus of CKDu development, where leptospirosis is prevalent, with a major outbreak occurring in 1995 after flooding [16,17]. In these CKDu patients, some have experienced clinical manifestations of acute infection, similar to having episodes of acute leptospirosis [18].…”

Leptospira and Leptospirosis

“…In 2007 and 2010, 685 and 653 cases were reported in this country, respectively [17]. After a typhoon in 2009, an outbreak of leptospirosis occurred in the Philippines.…”