Emergence and Reemergence of Infectious Diseases

Milton Friend Emeritus Scientist

U.S. Department of InteriorU.S. Geological Survey

“During the last 150 years the Western world has virtually eliminated death due to infectious disease.”

(U.S. Surgeon General, 1975)

“…it is time to ‘close the book on infectious diseases’.”

(U.S. Surgeon General, 1967)

Time Magazine

Number of People Worldwide with HIV/AIDS in 2002

Men 38.8 million

Women 19.6 million

Children <15 yrs 3.2 million

Total 42.0 million

U.S. AIDS-related mortalities (CDC data through 2001)

467,910

Disease Emergence

multi-pronged assault on humans by infectious disease

exotic diseases

novel diseases

‘resurgence’expanded distri

bution

“diseases and infections which are naturally transmitted between vertebrate animals and man.”

(World Health Organization, 1959)

Zoonoses =

DiseaseYear of

EmergenceWildlife Hosts

Monkeypox 2003 Prairie Dog

SARS 2003 Civet Cat

West Nile Virus 1999 Birds

Hantavirus 1993 Small Rodents

AIDS 1981 Nonhuman Primates

Lyme Disease 1975 Small Rodents

Notable Emerging Diseases with Wildlife Origins

Emerging Infectious Diseases of Wildlife

BirdsMammals – terrestrial and marineReptiles and AmphibiansFish – shellfish and finfishCorals

n=~190

West Nile Virus – Surveillance Activities

West Nile Virus – Necropsy Activities

2000 West Nile Virus Outbreak Timeline

May Jun Jul Aug Sep Oct

First P

ositiv

e W

ild

Bird

First P

ositiv

e M

osquito

es

Onset o

f Firs

t Hum

an

Case

Onset o

f Firs

t Hors

e Cas

e

First P

ositiv

e Sen

tinel

Chicke

n

West Nile Virus – Mapping

Wild Bird Surveillance

Human Cases

A Potential Wildlife Disease Surveillance Network

Specimens Submitted to NWHC (n=74,913)

Dept. of Interior

States

UniversityOthersOther Federal

Hepatopathy (Mycotoxin?)

Emerging Diseases Identified by NWHC

Inclusion Body Disease

Poxvirus

Nestling Herpesvirus

1970s

1980s

Pentobarbitol Poisoning

Mycotoxin Trichothecine

Woodcock Reovirus

Eastern Equine Encephalitis

Lake Andes Duck Plague

Hawaii Disease

Biocomplexity

Sea Otter Encephalitis

Avian Myelinopathy

Hepatopathy in Wisconsin

Stunting, Humpback

Chub

Sea Turtle Retrovirus

Rainbow Trout

Enteritis

Splenitis, Hepatitis in Brant

Coral Coccidiosis,

Tumors

1990s

2000s

LT Duck Adenovirus

Poisoning in Asian Vultures

Newcastle Disease

L. polyoon Enteritis

Chytrid Fungus/

Ranavirus

Emerging Diseases Identified by NWHC

???

1.9% (1.4-2.5%)n = 2602

0.2% (0.04-4.0%)n = 2393

0% (0-0.5%)n = 624

6.7% (5.7-7.9%)n = 1994

Model

Disease Distribution in Wisconsin’s Eradication Zone

Deer Processing Station

Specialized Biocontainment Facilities

Infectious Disease Investigations

Rabies

Wildlife

DomesticAnimal

Human

Translocation

Human encroachmentEx situ contactEcological manipulationHuman behaviors

Global travelUrbanizationBiomedicalmanipulation

Food processing/distributionTechnology andIndustry

AgriculturalIntensification

EncroachmentIntroduction“Spill over” &“Spill back”

SARS has cost an estimated $50 – $100 billion

Economic and Social ImpactsEconomic and Social Impacts

Tourism$

$ $$

$ Recreation

Commerce

Agriculture

Human Health

Component Primary Focus

Monitoring Disease patterns, trends, and geographic distribution

Surveillance Pathogen presence and disease activity

Reporting Real-time awareness and summaries

Field Response Disease control activities

Disease EcologyDisease maintenance, eruption and spread – finding the weak links

Technology Development New capabilities for disease detection, diagnosis and control

Interagency Collaboration Efforts crossing areas of jurisdiction/agency responsibilities

Training and Education Enhancing societal awareness, addressing disease issues

Components Required to Adequately Address Wildlife Disease

Characteristic HumansDomestic Animals

WIldlife

Species One Several Many

Species Biology & Ecology

Well Known Well Known Highly Variable

Disease Ecology* Well Known Well Known Poorly Known

Disease Control High Probability High ProbabilityLimited Success

Profession Long Standing Long Standing Recent Origin

Status of Knowledge for Disease Prevention and Control

* for established diseases

Non-Governmental Organizations

Department of Interior

State Wildlife

Agencies

Tribal Governments

General Public

Other Federal Agencies

Stewardship Network

Foundation for an Effective Wildlife Disease Capability

Operational Resources

Timely Response

Scientific Knowledge Early Detection

Rapid, accurate diagnosis

$$$

“...emerging zoonotic diseases are among the most important public health threats facing humanity.”

(Mahy and Brown, 2000)

“Pathogens that infect wildlife are twice as likely to become emerging diseases of humans as pathogens without wildlife hosts.”

(Cleaveland et al., 2001)

• Diseases in wildlife are often transmitted to humans

• USGS is well positioned to develop the type of wildlife disease program needed to best serve wildlife and human health

• Wildlife disease surveillance and monitoring are weak links in the protection of human health

• Wildlife are important to the national economy and natural heritage and can be impacted by disease

• USGS has increasingly been called upon to respond with its wildlife disease expertise to help combat emerging infectious diseases of humans, such as WNV and monkeypox.