Parmenter disease presentation - Ecological Society of America

The Ecological Society of America
Ecology of Zoonotic Diseases
Figuring out the What, Where and When
of Disease Outbreaks
Bob Parmenter, Director, Scientific Services Division, USDA Valles Caldera National Preserve, New Mexico
bparmenter@vallescaldera.gov, 505-428-7727
Gregory Glass, Professor, Johns Hopkins School of Public Health, Maryland, and
Director, Global Biological Threat Reduction Program, Southern Research Institute, Alabama; glass@sri.org
Lyme vector: black-legged tick
A West Nile Virus host: American Robin
Sampling rodents for Hantavirus & plague
Zoonotic Infectious Diseases:
Diseases from pathogens contracted from
animals (ticks, mosquitoes, rodents, etc.)
Pathogens include viruses, bacteria, and
parasites.
Lyme vector: black-legged tick
A West Nile Virus host: American Robin
Sampling rodents for Hantavirus & plague
Distribution of human deaths by cause
(world-wide, males and females)
Disease outbreaks
Distribution of human deaths by cause
(world-wide, males and females)
Disease outbreaks
Distribution of human deaths by cause
(world-wide, males and females)
Disease outbreaks
Distribution of human deaths by cause
(world-wide, males and females)
Disease outbreaks
Ecology of zoonotic diseases:
Routes of infection.
Direct pathogen transmission from animal to human
(rabies/mammals, hantavirus/rodents, influenza/swine
or fowl, Schistosomiasis/snails)
Rabies
Hantavirus
Influenza
Schistosomiasis
Pathogen transmission via a vector (Lyme disease/tick,
malaria/mosquito, plague/fleas, Leishmaniasis/sand
flies)
Lyme
disease
Malaria, West Nile
Plague
Leishmaniasis
Zoonotic disease outbreaks influenced by the
ecology of hosts, pathogens and humans
during interactions with the environment.
General categories of national significance:
1. Climate dynamics (short-term) and long-term
directional climate change
2. Land-use changes (anthropogenic and natural)
3. Global connectivity from travel and commerce
4. “Emerging diseases” from new discovery or
pathogen evolution
5. Biowarfare/terrorism
Understanding the ecology of infectious diseases:
National Science Foundation (NSF) Ecology and
Evolution of Infectious Diseases Program (EEID).
Ecological research on a diversity of diseases
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Echinococcus
Schistosomiasis
Malaria
Chagas
Trematodes
Hantavirus
Rabies
Encephalitis
Dengue
West Nile
P.Craig
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Herpesvirus
Canine distemper
Prion disease
Tuberculosis
Mycoplasma
Leptospirosis
E. coli
Plague
Cholera
Chitrid fungi
C. Kosoy
Scientific monitoring, testing and research on
outbreaks of zoonotic diseases: CDC
Special Pathogens Branch:
National and international
response collaborative teams
for sudden outbreaks and
newly emerging diseases.
Examples: How ecological dynamics influence host-pathogen
disease outbreaks – The 1993 Hantavirus epidemic in the Southwest
Sign in clinic
window, Gallup,
New Mexico,
during the 1993
outbreak of
Hantavirus
Pulmonary
Syndrome
Radiographic Progression of HPS
in the Lungs
May 27,
1993
May 30, 1993
Source: Dr. L. Ketai
May 31, 1993
After the first human cases in May,
CDC scientists identified the virus as a
Hantavirus in early June. Biologists
began field surveys of rodents, and
found the host was the deer mouse,
Peromyscus maniculatus.
Hantavirus host: Rodents
Transmission pathway: Direct
inhalation of virus in aerosolized
urine and feces
Exposure: Peridomestic,
recreational, occupational.
Mortality rate: 38%
Vaccine or cure: None
Transmission of Hantaviruses
Chronically infected
rodent
Horizontal transmission of
infection by mouse-to-mouse
aggressive behavior
Virus is present in
aerosolized excreta,
particularly urine
Virus also present in
throat swab and feces
Secondary aerosols, mucous
membrane contact, and skin
breaches are also sources of
infection
Ecological Drivers of Rodent-Borne Disease Outbreaks:
Trophic Cascades and Dispersal Waves
University of New
Mexico field crew
sampling rodents for
hantavirus in the Sandia
Mountains near
Albuquerque, NM.
Pulling blood sample from a deer
mouse (Peromyscus maniculatus)
Mobile field laboratory vehicle
Forest/woodland to grassland transitions
Sevilleta NWR
Valles Caldera National Preserve
Time of Onset of Human SNV HPS Cases Related to Linear
Distance from Refugia; 1993 HPS epidemic, Southwest USA
Distance (km) of SNV HPS patient’s home
from nearest “refugium”
24
16
8
0
0
30
60
90
120
Time (days) since start of epidemic
150
Time of Onset of Human SNV HPS Cases Related to Linear
Distance from Refugia; 1993 HPS epidemic, Southwest USA
Distance (km) of SNV HPS patient’s home
from nearest “refugium”
24
16
8
0
0
30
60
90
120
Time (days) since start of epidemic
150
Time of Onset of Human SNV HPS Cases Related to Linear
Distance from Refugia; 1993 HPS epidemic, Southwest USA
Distance (km) of SNV HPS patient’s home
from nearest “refugium”
24
16
8
0
0
30
60
90
120
Time (days) since start of epidemic
150
Time of Onset of Human SNV HPS Cases Related to Linear
Distance from Refugia; 1993 HPS epidemic, Southwest USA
Distance (km) of SNV HPS patient’s home
from nearest “refugium”
24
16
8
Why no cases under
the line????
0
0
30
60
90
120
Time (days) since start of epidemic
150
“With El Niño bringing a wet
winter, rodent populations
have ballooned to levels
approaching those in 1993,
when Hantavirus was first
identified in New Mexico”
The 1993 hantavirus
outbreak led to fears of
biowarfare and
terrorism. Congress
held hearings into the
causes of the epidemic.
(article from Scientific
American, November,
1993)
Rattus norvegicus
Microtus pennsylvanicus
Peromyscus maniculatus (grass)
Peromyscus maniculatus (forest)
Peromyscus leucopus (NE)
Peromyscus leucopus (NW)
Peromyscus leucopus (SW)
Reithrodontomys megalotis
Reithrodontomys mexicanus
Sigmodon hispidus texensis
Sigmodon hispidus
Sigmodon alstoni
Oryzomys palustris
Oligoryzomys flavescens
Oligoryzomys chacoensis
Oligoryzomys longicaudatus (N)
Oligoryzomys longicaudatus (S)
Oligoryzomys microtis
Calomys laucha
Akodon azarae
Bolomys obscurus
Seoul
Prospect Hill
Sin Nombre
Monongahela
New York
Blue River (IN)
Blue River (OK)
El Moro Canyon
Rio Segundo
Muleshoe
Black Creek Canal
Caño Delgadito
Bayou
Lechiguanas
Bermejo
Oran
Andes
Rio Mamore
Laguna Negra
Pergamino
Maciel
Colonization of North America by rodents.
ASIA
20 Million
years ago
† Copemys (16 Mya)


† Abelmoschomys (9 Mya)
Oryzomys?, Sigmodon?
7-9 Million
years ago

Auliscomys (4.5 Mya)
New World Hantaviruses
New York
Sin Nombre
Peromyscus leucopus
Peromyscus maniculatus
Prospect Hill
Microtus pennsylvanicus
Muleshoe
Sigmodon hispidus
Bloodland Lake
Microtus ochrogaster
Isla Vista
Bayou
Microtus californicus
Oryzomys palustris
Black Creek Canal
El Moro Canyon
Sigmodon hispidus
Reithrodontomys megalotis
Rio Segundo
Reithrodontomys mexicanus
Calabazo
Juquitiba
Zygodontomys brevicauda
Caño Delgadito
Choclo
Sigmodon alstoni
Oligoryzomys fulvescens
Rio Mamore
Oligoryzomys microtis
Unknown Host
Laguna Negra
Calomys laucha
Maciel
Necromys benefactus
Orán
Hu39694
Oligoryzomys longicaudatus
Unknown Host
Bermejo
Oligoryzomys chacoensis
Andes
Oligoryzomys longicaudatus
Lechiguanas
Oligoryzomys flavescens
Pergamino
Akodon azarae
Human Hantavirus cases in U.S., 1993-2012.
Histograms: Number of cases nation-wide
Black line: Percentage fatalities
Yosemite National Park, 2012 –
Hantavirus outbreak among visitors;
10 cases, 3 fatalities.
Double-walled tent-cabins provided perfect nest-site
habitat for deer mice…
Ecology Example #2:
Plague:
The “Black Death”
How do ecological factors
affect plague occurrence
and distributions?
Plague Cycle
Secondary
plague
pneumonia
Wild Rodent Cycle
Wild
Rodent
Direct contact
Bubonic
or Septicemic
plague
Infective
Flea
Primary
pneumonic
plague
cases
Direct
contact
Infective
Flea
contaminated soil
Direct contact
Wild
Rodent
Infective
Flea
Domestic
Rodent
Pathways
usual
occasional
rare or
theoretical
Infective
Flea
Domestic Cycle
Domestic
Rodent
Bubonic Plague:
Bubo locations
• Bacteria proliferate in
regional lymph nodes
• Locations*†
– Inguinal/femoral: 55-70%
– Axillary:
20%
– Cervical:
10%
• Most often solitary, but
can occur in multiple
locations (10-20%)
*Politzer R. Plague. World Health Organization Monograph Series. 1954.
†CDC. Unpublished data.
Photos courtesy of CDC.
Septicemic plague – infects entire
bloodstream, affects extremities first.
Photos courtesy of CDC, Public Health Image Library.
Pneumonic Plague – into the lungs
• Short incubation
period (1-4 days)
• Death in 3-6 days
if not treated early
• Primary
pneumonic plague
more easily spread
person to person
The Nippon Maru, docked in San Francisco, 1899.
Photo: Bancroft Library, U. C. Berkeley
Bob lives here
New Mexico: “Land of the Flea,
Home of the Plague”
Status of Plague in North America
“Plague Line” at
about the 100th
Meridian
Plague in the Southwest
• Almost 80% of U.S. cases
• Over 80% of cases exposed in
peridomestic environments
• Poor rodent sanitation increases
plague risks
• Rock squirrel fleas are primary
source of exposure
• Prairie dog flea bites and handling
infected prairie dogs, cats, rabbits,
etc. are also sources of exposure
(Eisen et al. 2007)
Areas at risk for peridomestic plague
Hypothetical
Pathways for
Plague Outbreaks:
1. “Trophic
Cascade” from
increased PPT,
raising numbers
of mammal hosts;
2. PPT increases
soil moisture and
enhances survival
and reproduction
of fleas.
3. Increased hosts
and fleas raise
probability of
plague events.
Impact of Late Winter Precipitation and
Threshold Temperatures on Human
Plague in the Four Corners Region
(Enscore et al. 2002)
Modified Trophic
Cascade Model
Increased rodent
Effects of Increased Precipitation
food sources
Feb. – March
(Major effect)
July – Aug
Cool summer
(15 – 18 months after first wet winter)
an
cr
(Major effect)
In
Rodent numbers
increase above critical
threshold (Davis et al.
2004 – Predictive
thresholds paper)
al
iv
rv
su
n
nt
tio
de
ro
uc
d
od
se
pr
ea
re
d
an
cr
In
Feb. – March
(Minor effect)
ea
se
d
d
fle
re
a
pr
od s u
uc rvi
tio va
l
n
(Minor effect)
Widespread
epizootics
High rodent densities
favor epizootic spread
Cool temperatures favor
survival of infected fleas
Enscore et al. 2002
Increased human plague risks
Supportive results observed for plague in prairie dogs
(Collinge et al. 2005) and in comparison of plague
and hantavirus risks in Southwest (Eisen et al. 2007)
PLAGUE PREVENTION
Fuge cito, vade longe, rede tarde
Flee quickly, go far, return slowly