Transcript InsectBonaire

Travel Medicine &
Insect-borne Illness
Bonaire May 2007
Joe Alcock MD MS, NM VAMC, UNM Dept EM
A bit about travel medicine
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Of 100,000 travelers to the
developing world in 1
month:
300 will require
hospitalization
50 will need air evacuation
1 will die
Traveler’s Mortality
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Cardiovascular
49%
Accidental Injury
22%
Infectious Disease
1%
So don’t smoke & do
wear your seat belts!
Common Travel Infections
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Salmonella
Shigella
Giardiasis
Amoebiasis
Hepatitis
Gonorrhea
Malaria
Helminth Infestations
Complaints of Returned
Travelers
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GI Illness 10%
Skin lesions 8%
Respiratory 5-13%
Fever 3%
Non-tropical = majority of
fevers
Tropical fever = Malaria
Source: CDC Yellow Book - www.cdc.gov/travel/yb/index.htm
Spring break in Mexico
Surfer returns from trip to Mexico, 3 days
later - fever 104, retro-orbital headache
 Doesn’t want to move
 Persistent nausea & vomiting
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Exam shows
erythematous
macular rash that
soon becomes
confluent.
Dengue (Breakbone) fever
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Flavivirus
Single-stranded
RNA
Widespread in
tropics
50-100 mil
cases/yr
250-500K
hemorrhagic
24K deaths
Aedes aegypti
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Patas blancas
Day biter
Restless feeder
Multiple hosts
Anthrophilic
2/3 world population
Between 30°N & 20°S
Common febrile disease in
travelers
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Dengue increasing
Vector likes small
collections H2O
Habitat for larvae
Insecticide Resistance
Increasing population
Urbanization
Fl. Dept Health
Classic Dengue
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Older kids and adults
Sudden onset fever
Headache, myalgias, arthralgias of shoulders
and knees
Prostating weakness
By 3rd day: rash over thorax, flexure joints
Hyperethesia, taste aberration
Defervescence
Dengue may mimic URI
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8 yo boy in Bankok develops mild fever, cough,
ST, rash. Misses 1 day of school, returns the
next day with no further symptoms and lifelong
immunity.
In Thailand only 13% miss school in <15 yo
group
Bangkok ~100% adult seroprevalence
> 15 yrs - classic dengue
San Salvador, El Salvador
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Female, 11, falls ill with fever, rash,
myalgias, vomiting. 4 days into illness
fever begins to decrease.
Confusion/somnolence.
Hct 38, then 45, then 50.
Edema, ascites, RUQ pain
B/P 70/34, requires IVF
CXR: large effusions, breathing is
labored, post-intubation coma briefly
precedes death.
Dengue Hemorrhagic Fever
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Rare
Typically afflicts patients < 15 years.
Diagnostic criteria include:
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Platelets <100K
Evidence of capillary leak, e.g. elevated HCT, ascites
of effusions, hypoproteinemia
Hemorrhagic manifestations/petechiae
Tourniquet Test
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Checks for
hemorrhagic
manifestations
Inflate blood pressure
cuff to median B/P for 5
min or until petechiae
are seen: > 3/sq cm
Treatment
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Supportive
No ASA/NSAIDs
Treat vascular leak with
IVF
Massive plasma leak
may last 48h
Correct coagulopathy
Death or complete
recovery
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Lab diagnosis has
limited clinical utility
Elisa tests now
available
Dengue Prevention
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No record of epidemic dengue 1946 and
1963
DDT
Yellow fever
Successful in Argentina, Belize, Bolivia,
Brazil, Chile, Colombia, C.R., Equador,
Guatemala, Mex, Panama, Uruguay
Discontinued in 1970s
Aedes aegypti
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Persisted in Caribbean Islands,
Venezuela, and USA. (!)
Reinfested countries where once
eradicated
Dengue outbreak in Jamaica 1977,
followed by epidemics until 1981 in every
Caribbean island, Central and South
America.
Experimental Vaccine
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Development started
in 1970s and 1980s at
Walter Reed lab
All 4 dengue
serotypes
Live attenuated virus
Incomplete immunity
may allow DHF if
reexposed
Meanwhile:
Yellow fever
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Flavivirus carried by
Aedes aegypti
200,000 cases/ yr; >20%
fatality rate
Children, infants at risk
Worse in Africa
Flu-like to fulminant
hepatitis
FULMINANT LIVER FAILURE
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Cytoplamic
coagulation in
hepatocytes
Councilman
bodies.
Yellow fever endemic areas
Yellow Fever
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New World via Africa in
1600s. Wiped out Carib
tribes
Maritime trade brings YF to
NYC, Boston, Halifax
Summer 1793 Philadelphia,
city of 50K. YF kills 10% of
population.
City paralyzed, survivors
abandon sick and dying.
Yellow Fever in Travelers
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Epidemic disease
10 cases since 1979
4 of 5 First world cases
1996-2002 visited South
America, All fatal
Risk to unvaccinated person
in endemic area is 1:1000
per month
Risk to US travelers = 0.4 -4
in million
Yellow Fever Vaccine
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Live attenuated virus.
Contraindicated in immunosuppressed
and children less than 4 years
Recommended for travel to Amazonian
region and parts of Panama. Also
equatorial Africa
Highly immunogenic/effective.
O.5 ml primary and 0.5ml 10 year boosters
YF Vaccine Risks
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Yellow Fever Vaccineassociated viscerotropic
disease
Clinically & Pathologically =
Yellow Fever
23 cases of vaccine disease,
14 fatal, 17% had had
thymectomy for thymoma
Elderly at risk
Malaria, by contrast
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No Vaccine
Malaria kills 1,500,000 yearly
Young children and pregnant women
Immunity partial and not durable
30,000 travelers: preventable illness
400 million cases worldwide
Malaria Case
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January 2006, a US
family w/ 5 kids visit
Nigeria
Pre-trip: pediatrician
gives prn meds only
No chemoprophylaxis
3 kids all given
Fansidar after fever
during trip.
Kids felt better
3 had return of fever in US
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Diagnosed with flu
Given antibiotics at
the local clinic
Then they got sicker
Mom notices 1 child is
very weak and has
yellow eyes!
Yellow Kid
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Conjunctivae icteric
Acidosis
Hypoglycemia
1 in 20 rbcs parasitized
Intubated
Transfused
All 5 kids tested pos for
falciparum malaria
Malaria Vector & Pathogen
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Female Anopheles - Crepuscular hours.
Congenital and transfusion - related cases
Autochthonous: single mosquito transmits
disease from 1 human to another
Malaria Parasite
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Major international
public health problem
Charles Laveran, a
French army surgeon
in Algeria, recognized
parasites in the blood
of a malaria patient in
1880.
Nobel Prize in 1907.
Role of Mosquitos
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1897, Ronald Ross, a
Brit in the Indian
Medical Service,
discovered that
mosquitos transmit
malaria.
For his discovery,
Ross was awarded
the Nobel Prize in
1902.
Major Public Health Problem
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Variable risk – regional
Caused by 4 protozoan species
Plasmodium falciparum
P. Vivax
P. ovale
P. malariae
Risk to travelers
Subsaharan Africa most falciparum cases
 500K US travelers to Africa vs. 21 million to
other malarious areas.
 Most malaria in SA and Asia is P. vivax
 Relative Risk to unprotected travelers:
Sub-Saharan Africa -1:50
India - 1:250
S.E. Asia-1:1,000
South America - 1:2,500
Central America -1:10,000
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Incubation
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Following the infective bite: incubation period
varies from 7 to 30 days
shorter with P. falciparum and longer with P.
malariae.
Prophylaxis delays symptoms by months, after
travelers leave endemic areas.
P. vivax and P. ovale: dormant liver stage
parasites; may reactivate and cause disease
Presenting symptoms
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Fever
Chills
Sweats
Headaches
Nausea and vomiting
Body aches
General malaise.
Exam findings
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Fever
Sweating
Weakness
Enlarged spleen.
In P. falciparum malaria:
Mild jaundice
Enlargement of the liver
Increased respiratory rate.
Severe Malaria
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Cerebral malaria, AMS seizures, coma
Severe anemia, hemolysis
Hemoglobinuria
Pulmonary edema (ARDS), may occur
even after treatment
Thrombocytopenia
Cardiovascular collapse and shock
Warning Signs
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Acute kidney failure
Hyperparasitemia, > 5% rbcs infected by
parasites
Metabolic acidosis
Hypoglycemia (low blood glucose), may
also occur in pregnant women with
uncomplicated malaria, or after treatment
with quinine.
Malaria Pathogenesis
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Malaria parasites digest RBC proteins and
use glucose to lactic acid as energy, thus
hypoglycemia & acidosis.
Injure RBC membrane: hemolysis, splenic
clearance & anemia.
Makes blood cells sticky - obstruct
microcirculation
Thrombocytopenia - splenic sequestration
Treatment
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Chloroquine
Atovoquone/ Proguanil (Malarone)
Quinine Sulfate and Doxycycline
Mefloquine side effects
Combination therapy with Artemesinin
P. vivax and malariae mostly chloroquine
sensitive
Expedition to Amazonia
While napping in a remote outpost, this pair
wakes up to find pale fleshy bugs on their
faces
Kissing Bug
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Barbeiro
Vinchuca
Reduviidae Triatoma spp.
Chagas disease
Chagas Disease
Carlos Chagas, Brazilian, described the
disease in 1909
He discovered the vector: Triatoma bug
He named the pathogen, Trypanosoma cruzi,
after his mentor, Oswaldo Cruz.
Carlos Chagas
Oswaldo Cruz
Triatoma
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Chagas is endemic from Mexico to Argentina
Transmitted by Triatoma bug - 30 species are
vectors.
9 of these vectors are in the US
Amazingly the bite is painless!
Chagas
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16 million infected in Americas
50,000 deaths per year
Indolent infections
Manifestations after years
Cannot be treated once chronic
Chagas results when parasite-laden feces
of bug are rubbed into eye/cut
Food-borne Chagas?
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Sugar cane juice
banned in Brazil
Guarapa
25 confirmed cases in
Santa Catarina BR
3 deaths
Symptoms arose
within days - virulent
NY Times April 12, 2005
Romana’s sign
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Hemilateral swelling
of face, eyelid, and
lymphadenopathy
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Acute Chagas
disease in a Brazilian
patient
American Trypanosomiasis
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Parasitemia C-shaped
trypomastigotes of T.
cruzi are seen in the
peripheral blood
“Mal de Chagas”
African Trypanosomiasis
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Related trypanosome
responsible for African
Sleeping Sickness
T. gambiense T. rhodesiense
Tsetse fly vector
Larger than T. cruzi
Chagas Disease
Amastigote T. cruzi
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Intracellular
Non-flagellated form
Indistinguishable from
Leishmania
Giemsa stain
Chagas in Tennessee
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In 1998,mother of 18 month infant found
triatoma bug in crib. Gut contents found
to contain Trypanosoma cruzi
Infant blood was PCR positive for T.
cruzi
2 of 3 raccoons trapped in area tested
positive for T. cruzi
Herwaldt B.L., et al. (2000) 1998. The Journal of Infectious Diseases 181: 395-399.
Chagas in America
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Animal reservior, T. cruzi, and Triatoma bugs are
all abundant
Local transmission epidemiology unknown
3 cases of acute Chagas disease have been
recorded in US
Exact number endemic cases unknown
Many more cases are imported
Chagas Heart Patients
Chagas Heart Syndrome
Ventricular Tachycardia, Syncope/Sudden Death,
Anginal Chest Pain, Symptomatic AV block, Congestive
Heart Failure.
EKG suggestive of ischemia
CAD mimic, underdiagnosed in US
LV aneurysm, regional hypokinesis, many require pacers
Hagar J.M. & Rahimtoola S.H. (1991) Chagas' heart disease in
the United States. N. Engl. J. Med. 325: 763-768
T. Cruzi myocarditis
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Amastigote in
cardiomyocyte
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Chronic Chagas
Cardiopathy
Autopsy of Bolivian Chagas
Case
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Infected cell in center
Diffuse lymphocytic
infiltration
Cardiomyopathy
Chagas in US
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Chronic Chagas
Disease reported in
Mississippi
Seropositivity in US
approximately
350,000 with 100,000
cases of chronic
disease
Megaesophagus,
cardiomyopathy
common
Holbert R.D., et al. (1995) J. Miss. State Med. Assoc. 36: 1-5.
Mega GI manifestations
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Megacolon in
Chagas in
Bolivia
May also
affect ureter,
bronchus,
esophagus,
uterus
Transfusion Risk
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In Latin America, blood transfusions are
major risk for Chagas transmission
ELISA assays are effective at detecting
Chagas antibodies in human serum
Carvalho MR et al. (1993) Transfusion 33: 830-834
Treatment
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Drug treatment for acute and congenital cases
Nifurtimox and Benznidazole can be used for
early chronic phase.
T. cruzi antigens stimulate autoimmunity, so no
vaccine
Travelers can avoid the disease by not sleeping
in infested housing.
Extra bonus arthropod!
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Yet another reason to use insect
repellent…
Bot Fly
Torsalo
Credit: Marcelo de Campos Pereira
Life Cycle
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When female
Dermatobia is ready
to oviposit she
captures another
insect - fly or
mosquito - and glues
eggs to captured
insect's abdomen.
Eggs hatch with
elevated temperature
Dermatobia hominis eggs glued to abdomen of carrier fly.
Third Instar Larva
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Prominent Mouth Hooks
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Larva in Holstein cow
Myiasis caused by Cordylobia
anthropophaga
Myiasis
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Second instar larva of
C. anthropophaga, an
African and Asian fly
Adapted to feed on
humans
In South America,
Dermatobia hominis
(Bot fly) is man-eating
maggot.
Bot fly
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Treatment/prevention Place Tiger Balm or
Camphorated Oil over every bite in endemic
area
Larva needs to breathe
Differential Diagnosis of Sebaceous cyst and
Infraorbital mass
Goodman et al. Arch Ophthalmol. 2000;118:1002-1003
Leishamaniasis
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Transmitted by
Phlebotomus sandfly
Asia/Middle East
Brazil/South America
Returned Military Personnel
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Leishmaniasis, the “Baghdad
Boil”
88 cases 2003 2004
“global struggle against armed
extremism” - increasingly
exposes Americans to tropical
diseases
Leishmania Life Cycle
The parasites invade the cells of the reticuloendothelial system,
such as macrophages, bone marrow cells, speen cells,
and the kupfer cells of the liver.
Leishmaniasis
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Leishmaniasis in 88
countries. 350 million
people.
Rain forests in Central
and South America to
deserts in West Asia.
90 % visceral
leishmaniasis: India,
Bangladesh, Nepal,
Sudan, and Brazil.
Kala Azar
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Visceral
leishmaniasis: fever,
weight loss, enlarged
spleen and liver
Low rbc, wbc, and
platelets
Espundia
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Untreated cutaneous
leishmania of the face
Treatment
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Sodium stibogluconate
Toxic to liver, heart, kidneys
Causes rash, pancytopenia, headache,
peripheral neuropathy
Better to prevent with Deet
Summary
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Classic Dengue: painful, afflicts teens/adults
DHF: <15yrs, bleeding and shock
Yellow Fever: liver failure, jaundice. Vaccine
Malaria; Falciparum fatal, no vaccine, anemia,
jaundice, coma, shock.
Chagas: indolent, thatch roof, heart & GI, blood
transfusions.
Bot Fly: excision vs. early petroleum jelly.
Leish: Sandfly, skin or visceral, toxic treatment
Use protective gear: nets, Deet, Permethrin
Travel Resources
CDC Yellowbook, International Bulletins
www.cdc.gov/travel/
http://www.cdc.gov/travel/yb/index.htm
www.cdc.gov/mmwr/international/world.html
Travel Health Info Line 877-FYI-TRIP
 UptoDate Travel Med monograph www.uptodate.com
 International Society of Travel Medicine
www.istm.org/
 World Health Organization
www.who.int/en/
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