GRF 2nd One Health Summit 2013: Presentation by Maria Cristina Schneider, World Health Organisation

2. Leptospirosis Outbreaks
in Nicaragua: Identifying
Critical Areas and
Exploring Drivers for
Evidence-Based Planning
M C Schneider, P Najera, S Aldighieri, J Bacallao, A Soto, W Marquino, L
Altamirano, C Saenz, J Marin, E Jimenez, M Moynihan, M Espinal
Author from: PAHO/WHO and Ministry of Health of Nicaragua
Int. J. Environ. Res. Public Health. 2012; 9(11):3883-3910.

3. Background – Leptospirosis in Americas
An emerging disease of epidemic-prone
Global alerts of leptospirosis, January 2010 to December 2012
Honduras
15 alerts
Nicaragua
45 alerts
530 global alerts of leptospirosis:
more than half (341 alerts) were in
the Americas
EUA
13 alerts
Dominican Rep.
19 alerts
Peru
16 alerts
Argentina
43 alerts
Source: HealthMap (http://www.healthmap.org), PAHO analysis
HealthMap is a database that utilizes different online sources for real-time surveillance of
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emerging public health threats.

4. Top infectious diseases in the Emergency Management
System/International Health Regulations
June 2007 to February 2013
Global
Leptospirosis is the
top 6 global
infectious hazard
Americas
Leptospirosis is the
top 3 infectious
hazard in the
Americas
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5. Background – Leptospirosis in Nicaragua
• Nicaragua is located in one of the subregions most vulnerable to natural
disasters. It faced leptospirosis outbreaks in 1995, 1998 (post-hurricane Mitch),
2007, and 2010; it has therefore acquired much experience.
• The current control and prevention activities against leptospirosis in Nicaragua
are being developed in all departments.
• The country has information on cases of
leptospirosis as well as demographic and
socioeconomic data broken down by
department and by municipalities.
• In place a Intersectoral National Plan
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6. Objective of the Study
Document the analysis of drivers in Nicaragua in order to identify areas at
risk for outbreaks of leptospirosis. It is hoped that this study will serve as a
methodological basis for the identification of areas at risk for leptospirosis
in other countries in Latin America.
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7. Methodology
Type of study, period and data source
• Ecological-type study by second subnational level (153
municipalities in 17 departments of Nicaragua); retrospective
and descriptive when it comes to describing outbreaks and
interventions
• From 2004 to 2010
• Secondary sources and data, sources from the country’s
information system, the 2005 Nicaragua Census, and other
different sources
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8. Methodology
Steps
•
Description of the actions for prevention/response for leptospirosis in the
country
Definitions and criteria
Description of the epidemiological situation and risk stratification
Created from scratch a database (GIS) with cases, socioeconomic and
environmental variables (by municipality)
Exploratory analysis (statistic and GIS)
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•
•
•
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9. Results
Cases of leptospirosis, Nicaragua, 2004-2010
Source: Ministry of Health of Nicaragua
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10. Results
Cases of leptospirosis, by department, Nicaragua, 2004-2010
Cases
304
Chinandega
979
522
175
Leon
Managua
Others
50% of the cases
in 3 departments
Source: Ministry of Health of Nicaragua
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11. Total number of cases of leptospirosis and cumulative incidence
rate (10,000 populations), by municipality, Nicaragua, 2004–2010
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Source: Ministry of Health of Nicaragua; authors’ analysis

12. Risk stratification of leptospirosis in Nicaragua
Upper quintile
cases &
incidence rate
Yes
Critical area
48
133/153
Lower quintiles
cases &
incidence rate
Productive area?
(occurrence of leptospirosis cases)
Endemic area
85
No
20/153
Total municipalities = 153
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Silent area
20

13. Risk stratification of leptospirosis in
Nicaragua, by municipality, 2004–2010
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Source: Ministry of Health of Nicaragua; authors’ analysis

14. Critical areas for leptospirosis represented by incidence rate
and percentage of soil with Cambisol and Andosol, by
municipality, Nicaragua, 2004–2010
Cambisol
Young, with changes in
color, structure, and
carbonate washing
Andosol
Soil from volcanic ash
FAO. Mapa Digital del Suelo del Mundo. Base Mundial de Referencia para los recursos del Suelo (FAO/ISRIC/SICS, 1998,
rev 2010. Base de datos: GeoNetwork
Bull World Health Organ. 1961; 24(1): 35–43 The effect of pH on the survival of leptospires in water*
C. E. Gordon Smith and L. H. Turner http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2555367/ One of the factors on which the incidence of leptospirosis is dependent is the survival time of shed
leptospires in surface water or soil water, and this time is in turn affected by the acidity or alkalinity of the water.

15. Average rainfall and total number of cases of
leptospirosis, in the next month, by municipality
Nicaragua, 2004–2010
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Source: Ministry of Health of Nicaragua; authors’ analysis

16. Critical areas for leptospirosis represented by incidence rate and
percentage of rural population, Nicaragua, by municipality 2004–2010
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Source: Ministry of Health of Nicaragua; authors’ analysis

17. Results -Exploratory Analysis
Possible drivers
% rural population
Average of
municipality
Standard
deviation
61.3
24.246
Minimum rainfall per year
(mm)
165.6
204.701
Average rainfall in the two
months with the most rain
during the year (mm)
7,403
1,490
% of type of cambisol and
adenosol soil
51.7
42.470
Correlation with
cumulative
incidence rate
0.20666
p= 0.0104
-0.23927
p=0.0029
0.18074
p=0.0254
0.27475
P=0.0006
4 models were done for the exploratory analysis; in 3 precipitation emerge as a
relevant explanatory variable; in the Poisson model these 4 variables have significant
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p < 0.01.

18. Conclusions and Recommendations
• Outbreaks do not occur on a yearly basis
• The risk is different between the departments and municipalities
• Importance of multidisciplinary study team and One Health approach
• The limitations of ecological study are highlighted
• Possible socioeconomic drivers are highest in the Atlantic region where
environmental factors are less present (another study for the Pacific region)
• Addition studies suggested: Analysis of the actions; more disaggregated analysis by
household or individual; complementary studies in the animal populations
• This methodology could further assist other countries in the region without a
surveillance for leptospirosis to define their areas at risk.
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19. Conclusions and Recommendations
This type of information could be used in Nicaragua’s Intersectoral National Plan in
the definition of priority areas for action and periods of the year for time of
interventions.
Example of potential use of this information for planning to prevent and respond to
leptospirosis outbreaks in the case of Nicaragua
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20. Thank you very much!
www.paho.org/leptospirosis
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