Transcript Slide 1

What’s happening out
there?
Global Shifts in Disease
Musings of Paul Van Caeseele, MD
April 25, 2008
Objectives

Bird’s eye view of what’s going on



Select diseases emerging and reemerging
Introduction to some of the drivers affecting
disease and travel around the world
Learn something that will broaden thoughts of
what travel medicine could encompass
Reemergence of
Vaccine Preventable Disease & Other
Old Friends

In the last few years, we’ve witnessed outbreaks
of well-suppressed VPD’s
Diphtheria (Russia, 1993-96)
 Measles
 Mumps


Resurgence of dormant diseases or common
diseases with twists
Diphtheria, USSR, 1993-96



Huge jump in
cases due to
collapse of Soviet
infrastructure
>130,000 cases
over 4 years
>4000 deaths
that decade
Vitek & Wharton, 1998
Measles

What

Sporadic measles appearing in limited outbreaks


Ontario limited outbreak



Most propagated due to inadequate vaccine coverage, i.e less than two
doses MMR, killed vaccine only
More noted in adolescent to adult age groups (atypical to historical 510 year age group)
Larger European outbreak




Most begin with an importation
>250 cases associated with anthroposophic (naturalistic) schools
“mobile communities” felt to be the source
Mostly noted in childhood age groups due to low vaccination rate
So What?

Measles leading cause of death due to “respiratory disease” in
the third world
Anthroposophy


A spiritual philosophy based on the
teachings of Rudolph Steiner (18611925)
Believes in the existence of an
objectively experienced spiritual
world that can be accessed with
proper inner development


Mysticism meets Science
Very active movement in many
areas, including schools, with >900
Steiner/Waldorf schools worldwide

What

Large outbreak across Canada (&
others)





Mumps
>1200 cases in 2007, mostly in NS,
NB, AB
Mostly 20-29 year olds with
incomplete immunity, highly social
and highly mobile, often nonadherent
Only 8% had two doses of vaccine
Also in Ireland, Australia, England,
USA
So what?


High incidence of orchitis and
hearing loss
Appreciable rate of encephalitis and
mortality
Flaviviruses

Mosquito-borne viruses that include
West Nile Virus
 Yellow Fever Virus
 Japanese Encephalitis Viruses
 Dengue Viruses


Increasing due to increasing travel, trade,
urbanization, inattention to control programs
Dengue fever

Still a major concern


Mosquito born virus cases “break-bone fever”






50-100 million infections per year
Frequently asymptomatic
May be complicated by diatheses, hepatitis, MTCT
Second time around at risk for DHF – Dengue Hemorrhagic Fever
(mortality 1-50%)
Many tropical beaches at risk nowadays
More frequently diagnosed than malaria in travelers from South
America and Asia
Australian travelers 10X more likely to have Dengue coming
from Asia
Peteresen & Marfin, 2005
Skin infections

Remain a common problem
10-23.4% of travelers return with skin problem
 8-18% of these are infections1
 Some specific likelihoods

Belize – cutaneous myiasis (Dermatobium hominis)
 Rickettsial – South Africa & Zimbabwe
 Leishmania - Columbia
 <18 years more likely to have CLM & dog bites
 >65 more likely to have rickettsial disease or cellulitis21

1.
Schleucher et al, 2008
2.
Lederman et al, 2008
New Dangers

Staphylococcus aureus
Reports of returned travelers with recurrent skin
infections
 MRSA sometimes cultured
 Panton-Valentine Leukocidin (PVL) positive strains
not uncommon1

Cytotoxin causing tissue necrosis
and WBC destruction
 Increasingly prevalent in Canada
 Seen in CA-MRSA, usually native strains

Schleucher et al, 2008
Series #1

Following a report of imported MRSA in Ireland,
Scottish group reported




14 cases of recurrent or moderately severe cutaneous
All associated with travel, non hospital-associated
Some persisted for >3 years
Noted that antibiotics commonly used in travel
prophylaxis (or empiric treatment) were ineffective

Doxycycline and ciprofloxacin resistance noted in some
Helgason et al, 2008
Series #2

German study also noted that
Panton-Valentine Leukocidin-positive MRSA isol.
 Mostly imported and associated with

Travel to Mediterranean
 Travel to Middle East


Some also no recent travel but did have family from
the Mediterranean
Maier et al, 2005
MRSA Continued

One Danish Study found evidence of
importation of strains1
Usually skin and soft tissue infections
 Highly associated with arrival from Balkan refugee
camps, travel to Mediterranean or Middle East
 Evidence of transmission in families
 They were able to eradicate effectively


Hajj only carry MRSA 1.6% of the time2
1.
Larsen et al, 2008
2.
Memish et al, 2006
Invasive MRSA Rates in Europe, 2004
Bioquell, 2008
Implications: MRSA


No longer just a hospital-acquired infection
There may be a future for services targeted at the
highest risk travelers

Athletes, especially wrestlers, football players




Early detection and segregation
General hygiene and equipment cleaning
Immunocompromised
Tropical travel would predictably be higher risk (SSTI)


Bring empiric topical antibiotics/disinfectants for injuries as a
routine? (similar to contact lenses)
Often routinely included in “adventure” travel first aid kits
Benjamin et al, 2007
Clostridium difficile: What now?

Increasing virulence and presence locally



Increasing numbers of reports of C. difficile in returned
travelers with persistent diarrhea



One third to one half of local cases are community acquired
– suggests higher carriage rates
No stats on presence in returned travelers, and it is still a low
probability
Severe cases marked by loperamide and (multiple) courses of
antibacterial use
Colectomy reported, deaths uncommon
So what?

Tweaks to advice on management of diarrhea may become
necessary
Chikungunya Virus






Means “that which bends up” (Makonde) or “walking
hunchbacked”
Mosquito borne virus causing explosive onset disease
with fever, severe arthralgia, hemorrhagic disease (25%)
“inactive” for 20 years
Prolonged joint pain is
very common
Usually self-resolves
Co-circulates with Dengue,
often under or mis-diagnosed
Chikungunya Distribution

The distributor


Aedes spp.
Works during the day

Her sales area
Confirmed Sales: Réunion

2005-2006 epidemic on the Isle of Réunion

Population 750,000, cases ~218,000 (29%)
Eurosurveillance, 2006
The International Concern



No vaccine
Aedes exists in many other areas of the world
and could gain a foothold
Some mortality possible
(more virulent?)
Chikungunya Market Collapse

Good news: the travel advisory is over as of
December 2007
Still a low risk and typically self-resolving disease
 Daytime mosquito prevention works (repellent, light
coloured clothing, etc.)


Bad news: it will be back

Still going moderately strong in India, Indonesia and
Sri Lanka (Italy in late 2007)
What is a shift?


Most of what we have discussed could easily fall
into predictable cyclical or sporadic activity
Shift
A change or move (outside of the norm)
 A systematic change as something evolves
 May be of different types, for example

Clinical
 Demographic/Epidemiologic
 Geographic
 Genetic

Death rates due to VPD in US
Death Rates Compared in US
Ausubel et al, 2001
Travel Economics

Travel trends affected by


Strength of local currency vs. costs (oil)
Safety abroad (SARS, war, etc.)


Demographics




Demand for “high-risk” 1 or adventure travel
More singles (MSM and young adults)
More grandparents (some with grandchildren) (denture ventures)
More large families2,3
“Conscious” tourism

Ecotourism and geotourism
1.
Valerio et al, 2005
2.
World Travel Trends Report, 2006-7
3.
Statistics Canada, 1997
Economic Impacts?

For us in Travel Health

More retirement age travel (more co-morbidity 24-35%)







15% Thai backpackers >55y1
More immunocompromised also travel – dialysis cruises (2004 >18,000), transplant patients (2004 - ~1800) 2, etc.
Phase advance (eastward jet lag) longer recovery time3
IM Needle length adjustments for body mass (1-1.5”) 1
More adventure and backcountry travel (more exposure to
harsh environments)
More pediatric considerations in both
In general

Much more travel, much more “risky” travel
1.
Reed, 2007
2.
CIHI, 2006
3.
Brendel et al, 1990
Other Hazards: Habits of the Polar
Fox, Alopexlagopus
Verhoeven et al, 2007
Conscious Tourism

Geotourism

“tourism that sustains or enhances the geographic character
of a place” (environmental, cultural, heritage and well-being)
1

Ecotourism


“Germophobic”


An ecotourist is one with “ceaseless expectations for unique,
authentic travel experiences that preserve the ecological and
cultural environment”1
One marketing study indicates an increased awareness of
germs (80% are concerned, 55% wash hands more, 27%
bring own sheets/towels/sanitizers, n=2500)2
Movement in the industry to accommodate these
1.
National Geographic Society, 2002
travelers
2.
Hotel Industry News, Oct 2007
Medical Tourism

Increasing awareness of health-driven tourism

Medical Tourism (750 K Americans/yr projected)




Reproductive Tourism




Travel across borders to receive health care
Canada third largest consumer based on indirect reports
Surgical procedures (Plastic and Dental) seem to predominate
Assisted reproduction and IVF
16% in one US Clinic were Canadian patients2
Not all countries adequately screen, and ovarian hyperstimulation can
be dangerous (one fatality in Ireland)
Transplantation Tourism

Foreign travel to receive transplants
1.
Patel et al, 2007
2.
Leigh, 2005
Companion Animals


Because pets are people too
Increasing interest in their travel-acquired disease



Increasingly brought on travel
Small animal travel increasingly important
Imported pathogens/diseases may be poorly recognized here
and pose a risk for:



Autochthonous transmission
Zoonotic transmission
Decreasing vet skill in diagnosing


Reflexive antiparasitics
Increasingly urban practice
1.
Deplazes, 2006
2.
Irwin, 2002
Some Veterinary Examples

Increasingly immunocompromised animals


Giardia





Travel to high-risk areas a well known risk
Transmitted by mosquitoes
Canine Babesiosis


Affects canines as well as humans
Gastrointestinal disease very common in canine pets
High rates of Giardia carriage, even in well-cared
Heartworm (Dirofilaria)


Aged or on immunosuppressive therapy
Cause of refractory anemia, frequently mistaken for
autoimmune
Also Echinococcus, Brucellosis, Lyme, etc.
Way out There

One author suggest that xenotransplantation
may be the wave of the future1
Animal organs in humans in foreign countries
 Potential for “xenoses”

1. Graczyk et al, 2005
Climate Change: What’s Happening


Is it real?
Average temperatures worldwide rise
0.6º C rise in last 100 years
 Rising faster (3º C in the next 100 years)


Average sea level rising
Risen >3 inches since 1961
 Projected to rise another 7.1 to 23.2 inches by 21001
 25% of US coastal houses and resorts are
anticipated to be submerged by 20602

1.
Intergovernmental Panel on Climate Change report, 2007
2.
Heinz Centre for Science, Economics and Environment, 2000
Climate Change & Health

WHO now recognizes climate change as a danger to
human health


Not as a sole determinant, but important
Recognizes these examples







Hurricane Katrina, 2005
2003 European Heat Wave (22-45 K)
Cholera in Bangladesh
Malaria in East Africa
Droughts in numerous locations
Least resourced areas will be least able to cope
By 2030, attributable excess risk outcomes will likely double
WHO, April 2008
Natural Disasters in Canada, 1900-2002
Etkin et al, 2004
Insect Vectors and Warmer Weather

Increase in malaria?




Anopheles do not breed or develop well below 16º C or above
40º C (Dengue limited by winter temperatures <10º C)
A 3º C rise in average global temperatures (by 2100) could
lead to 50-80 million more cases of malaria1
Higher altitudes (Asia, Central Africa, Latin America) now
seeing more mosquito born disease due to presumed
influence of warming2
Other Insect vectors

Black-legged Ticks moving north in Scandinavia, expected to
do the same in North America3
1.
Martens et al, 1995
2.
Epstein et al, 1998
3.
Epstein, 2005
Projected Ranges of Ixodes scapularis in Canada
Ogden et al, 2005
Areas vulnerable to malaria in the African Highlands
Patz & Lindsay, 1999
Probable Endemic Malaria in US and Canada,
1882
Reiter, 2001
Hot Weather Effects

Heat waves


Particularly bad in urban setting (heat island)
Kill or hospitalize thousands


Chicago 1995, Europe 2003
Other effects




Enhances smog, dust, mold and pollen persistence (elevated
CO2 also exacerbates)1
Higher rates of asthma
More urban violence2
Changes in migration of birds, bats and other animals
1.
Epstein, 2005
2.
Health Canada, Nov 2005
Water: Too much or too little

Too much

Flooding and excess rain linked to (w. other factors)1




Coastal rises


Greater mosquito populations = Malaria
More standing water = Diarrhea, cholera, schistosomiasis
More rodentia = Plague, Hantavirus
200 million at risk from coastal storms (13/20 megacities)
Too little



Drought (affects local economies and food prod.)
Forest fires (deforestation and smoke)
Water crises (violence)


>1.7 billion live in water stressed conditions
Projected to rise to 5 billion by 2025
Patz and Kovnats, 2005
Peter, 2007
Implications for Us?

Changing trends in & geography of disease



Shifting malaria & vector borne disease regions
Potential for many regions to be in seasonal crises
More early warning systems

El Niño and other weather pattern monitoring can be predictive for some
regions and diseases



Measures to mitigate warming (Greenhouse gases?)


Malaria (SA), plague, Hantavirus, (cholera), dengue
Heat waves in Europe, Asia
Preserve forests and greenery
On a more personal note…


Prairies and North expected to be hit hard
No Health Plan works for all climates
El Niño
Affected
Weather
Patterns in
Dec-Feb and
Jun-Aug
Patz & Kovats, 2002
The Walk Away Message



The last century was very interesting
The next century may be even more interesting
We’ll have this talk again in 100 years
Thank you
v.3