GRF 2nd One Health Summit 2013: Presentation by Claudia Munoz-Zanzi, University of Minnesota

1. DRIVERS OF LEPTOSPIROSIS
TRANSMISSION AT THE HUMANANIMAL INTERFACE IN DISTINCT
COMMUNITY TYPES
Claudia Munoz-Zanzi, DVM, MPVM, PhD
Division of Epidemiology and Community Health
School of Public Health
University of Minnesota

2. Leptospirosis transmission cycle

3. Leptospirosis transmission cycle
• Components

4. Leptospirosis transmission cycle
• Components
• Transmission
dynamics within
each host species

5. Leptospirosis transmission cycle
• Components
• Transmission
dynamics within each
host species
• Interactions between
Components
Variations expected by
social (urban, farms,
villages) and
environmental/ecological
(temperate, tropical,
subtropical, arid,
Mediterranean) conditions

6. Study site: Los Rios Region, Chile
Climate
Temperate rain forest
Rainfall: 2,588 mm
Temperature: 17°C
summer and 8°C in
winter
Demography
364,592 hab.
% rural: 40%
% poverty: 20%

7. R. rattus
R. norvegicus
M. musculus
Wild rodents
Total
13%
0%
11%
25%
14%
Urban slums
Puddles
27%
Household water 5%
U-1
U-2
U-3
U-4
U-1
U-2
U-3
U-4
32%
68%
44%
40%
29%
3%
0% 2%
2%
5%

8. Rural villages
R. rattus
R. norvegicus
M. musculus
Wild rodents
Total
21%
33%
54%
27%
24%
Puddles
23%
Household water 0%
C-1
C-2
C-3
C-4
Cattle
47%
Sheep
16%
C-1
C-2
C-3
C-4
26%
15%
36% 23%
0%
0%
0% 1%
1%
1%

9. Farms
R. rattus
R. norvegicus
M. musculus
Wild rodents
Total
22%
4%
23%
17%
19%
Puddles
35%
Drinking water
23%
D-1
D-2
D-3
D-4
Cattle
27%
Sheep
16%
D-1
D-2
D-3
D-4
0%
13%
12%
5%
18%
0%
8% 4%
2%
5%

10. Putting it all together
Epidemiological studies:
 Leptospira in dogs:
 dog density,  slums
 rainfall 1-month prior
 Leptospira in puddles:
 Leptospira in rodents:
 dogs  temperature 1-week prior
 No. rodent signs,  rainfall 1-week prior
 farm household income
 farms,  Spring,  mice
 Leptospira in people:
 farms,
 women from slums
 men from farms
Molecular/serology studies:
Spatial studies:
 Leptospira in puddles from slums:
 Positive rodent 50 m buffer
 Specific habitats (wetlands, forest) in a 250m buffer
 Flow accumulation index, rainfall 1-week prior

11. For a given specific community type,
in a specific region:
Changes in the interactions between the components and/or
in the drivers of within-species transmission and/or drivers
of environmental contamination lead to:
- different levels of endemicity in different regions
Sao Paulo, Brazil

12. For a given specific community type,
in a specific region:
Changes in the interactions between the components and/or
in the drivers of within-species transmission and/or drivers
of environmental contamination lead to:
- different levels of endemicity in different regions
- seasonal changes in incidence
Trinidad and Tobago

13. For a given specific community type,
in a specific region:
Changes in the interactions between the components and/or
in the drivers of within-species transmission and/or drivers
of environmental contamination lead to:
- different levels of endemicity in different regions
- seasonal changes in incidence
- outbreaks

14. Take home message
• Transmission dynamics are complex and
heterogeneous, with changes that occur at different
scales
• Multidisciplinary team of investigators, training
(from undergrads to post-docs), and capacity
building
• More research is needed that includes:
– Prospective eco-epidemiological studies in
different community types from different regions
– Development of predictive/risk assessment
models

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Research Team
Carolina Encina , Miguel Salgado – Universidad Austral de Chile
Maria Diuk-Weisser – Yale University
James Lloyd-Smith – UCLA
Renee Galloway – CDC
Students
Marcelo Gonzalez (DVM)
Gunther Heyl (DVM)
Carolina Munoz (DVM)
Cesar Bauza (DVM)
Angel Astroza (PhD in Microbiology)
Meghan Mason (PhD in Epidemiology)
Bozena Morawski (PhD in Epidemiology)
Sergey Berg (PhD in Conservation Ecology)
Maud Lelu (Post-doc, Ecology and Modeling)
Hannah Fox (MPH in Maternal and Child Health)
Chris Campbell (MPH in Epidemiology)
Ashley Bekolay (MPH in Environmental Health)
Brooke Higgins (Undergrad, Biological Sciences),
Sarah Blau (Undergrad, Pre-Med)
Megan Girsh (Undergrad, Ecology)
Funding
– National Science Foundation
• Ecology of Infectious Disease Program (No. 0913570)
• Research Experience for Undergraduates Program
– University of Minnesota
• Epidemiology PhD Program Graduate Student Scholarship
• Undergraduates Research Opportunity Program (UROP)
• Grant-in-Aid Faculty Research Program
• Global Spotlight Program
– National Institutes of Health
• NIAID R03