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Vector-borne InfectionsVector-borne Infections
Allison Liddell, M.D.Allison Liddell, M.D.Infectious DiseasesInfectious Diseases
September 25September 25thth, 2006, 2006
Clinical Vignette
28yo FBI agent on temporary assignment in the Nantahala forest in Western North Carolina presents with acute onset fever, chills, headache 3 days after Memorial Day.
Exam: confused, ill appearing, a few petechiae present on wrists and ankles
Labs: platelets=75K, mild leukocytosis, mildly elevated transaminase
LP with 75 WBC, mostly lymphocyes with protein=154
Tick-Borne Infections in Tick-Borne Infections in the U.S.the U.S.
Lyme diseaseLyme disease Rocky Mountain spotted Rocky Mountain spotted
feverfever EhrlichiosisEhrlichiosis TularemiaTularemia BabesiosisBabesiosis Colorado tick feverColorado tick fever Tick-borne relapsing Tick-borne relapsing
feverfever Tick-borne encephalitisTick-borne encephalitis Tick paralysisTick paralysis Q FeverQ Fever
Ticks as Effective Disease Vectors:
Feed on blood Wide host range Persistent attachment
(painless)- wide dispersal Longevity Transovarial transmission
(RMSF, tularemia, Babesia) Few natural enemies Resistant to environmental
stresses High reproductive potential
Questing tick
Rocky Mountain Rocky Mountain Spotted FeverSpotted Fever
Described in late 1900’s in Bitter Described in late 1900’s in Bitter Root ValleyRoot Valley
Caused by infection with Caused by infection with Rickettsia Rickettsia rickettsiirickettsii
Obligate intracellular, requires cell Obligate intracellular, requires cell culture to cultivateculture to cultivate
RMSFtransmission
Maintained transovarially in Maintained transovarially in ticksticks
Tick vectors are hard ticks:Tick vectors are hard ticks: Dermacentor variabilisDermacentor variabilis
(eastern US)(eastern US) D. andersoniD. andersoni (western US) (western US) A. americanumA. americanum (south- (south-
southwestern US)southwestern US)
Parola, Clin Infect Dis 2001 Mar 15;32(6):897-928
RMSFepidemiology
Most cases occur Most cases occur May – SeptemberMay – September
Highest rate in Highest rate in children 5 - 9 yearschildren 5 - 9 years
Exposure to dogs, Exposure to dogs, grassy areas risk grassy areas risk factorfactor
8.5% mortality (Billings et al)
TDH Website
TDH Website
RMSF Clinical ManifestationsClinical Manifestations
Incubation period 2 - 14 daysIncubation period 2 - 14 days Onset with fever, myalgias, headacheOnset with fever, myalgias, headache GI findings may mimic an acute abdomenGI findings may mimic an acute abdomen Rash appears 3 - 5 days after onset of feverRash appears 3 - 5 days after onset of fever Meningismus and CSF pleocytosis may occurMeningismus and CSF pleocytosis may occur WBC usually normal, platelets often WBC usually normal, platelets often
decreaseddecreased Hyponatremia occurs in 50%Hyponatremia occurs in 50%
RMSFDiagnosis
Serology IF staining of tissue
specimen PCR under
development
RMSFOutcome
N=6388 over 1981-1998 Annual case-fatality rate 3.3% Risk factors for mortality:
Old age Chloramphenicol only Tetracycline not primary therapy Treatment delayed > 5 days
Holman et al JID 2001
Clinical Vignette
54 yo WM farmer in Missouri presents with 3 day h/o high fevers, chills, headache and marked malaise in June
Exam notes a confused, ill-appearing man but is otherwise unremarkable
Labs note transaminases 3 x normal, platelets 115K, WBC 2.1, CSF 32WBC, protein 127
History of History of EhrlichiosisEhrlichiosis
1935 - 1935 - E. canisE. canis-hemorrhagic -hemorrhagic illness in Algerian dogsillness in Algerian dogs
1950s – 1950s – E. sennetsuE. sennetsu--mononucleosis-like illness in mononucleosis-like illness in JapanJapan
1986 – Ehrlichiosis-patient in 1986 – Ehrlichiosis-patient in Detroit after tick bites in Detroit after tick bites in ArkansasArkansas
1991 - 1991 - E. chaffeensisE. chaffeensis cultured cultured from patient at Fort Chaffee in from patient at Fort Chaffee in ArkansasArkansas
Genus Genus EhrlichiaEhrlichia
Small gram-negative bacteria Small gram-negative bacteria closely related to closely related to RickettsiaeRickettsiae Obligate intracellular Obligate intracellular
parasitesparasites Infect circulating blood Infect circulating blood
elementselements Reside and replicate within Reside and replicate within
membrane-bound membrane-bound cytoplasmic vacuolescytoplasmic vacuoles
Vertebrate reservoirs and Vertebrate reservoirs and arthropod vectorsarthropod vectors
EHRLICHIA CASES BY AGE, ST. LOUIS, 1994-2000
02468
10
1214161820
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 >80
Nu
mb
er o
f ca
ses
EHRLICHIA CASES BY MONTH, ST. LOUIS 1994-2000
0
5
10
15
20
25
30
35
40
45
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Nu
mb
er o
f C
ases
Ehrlichia ewingiiEhrlichia ewingii First discovered in dogs with First discovered in dogs with
granulocytic ehrlichiosis, 1992granulocytic ehrlichiosis, 1992 Disease is milder than Disease is milder than E. canisE. canis
infectioninfection Manifestations include fever, Manifestations include fever,
lethargy and polyarthritislethargy and polyarthritis Found to date in dogs in Found to date in dogs in
Missouri, Arkansas, Missouri, Arkansas, Oklahoma and N. CarolinaOklahoma and N. Carolina
Member of Member of E. canisE. canis genogroup genogroup (cross-reactivity)(cross-reactivity)
Experimental transmission by Experimental transmission by A. americanumA. americanum
Ehrlichiae Causing Human & Ehrlichiae Causing Human & Veterinary DiseaseVeterinary Disease
Day of Treatment & Risk of Day of Treatment & Risk of Complications/DeathComplications/Death
EhrlichiosisEhrlichiosis
Day of Rx Odds Ratio P
1 – 3 1.0 -
4 – 7 2.50 0.114
> 7 4.48 0.014
Fishbein DB et al, Annals Intern Med, 1994
Human Ehrlichiosis Symptoms
HME HGE
Fever 97 94-100
Headache 81 61-85
Myalgia 68 78-98
Malaise 84 98
Rash 36 2-11
Confusion 20 17
Dumler et al, Annu. Rev. Med. 1998. 49:201-213
Human EhrlichiosisHuman EhrlichiosisClinical SpectrumClinical Spectrum
DICDIC PancytopeniaPancytopenia Encephalitis/MeningitisEncephalitis/Meningitis Pulmonary Pulmonary
infiltrates/Respiratory infiltrates/Respiratory failurefailure
Gastrointestinal Gastrointestinal bleedingbleeding
Renal FailureRenal Failure
Human Ehrlichiosis Human Ehrlichiosis LaboratoryLaboratory FindingsFindings
LeukopeniaLeukopenia
ThrombocytopeniaThrombocytopenia
Elevated transaminasesElevated transaminases
HyponatremiaHyponatremia
>>4-fold elevation in IFA4-fold elevation in IFA
PCRPCR
RMSF/EhrlichiosisRMSF/EhrlichiosisTreatmentTreatment
Adults:Adults: Doxycycline 100 mg Doxycycline 100 mg bidbid
Children:Children: Doxycycline 3 mg/kg/day in Doxycycline 3 mg/kg/day in 2 divided doses2 divided doses
Duration: 3 days after defervescence, Duration: 3 days after defervescence, minimum 5-7 daysminimum 5-7 days
Clinical Vignette
34 yo WF owner of a campground presents with a nonhealing lesion on the right index finger for 2 weeks, adjacent to the nail bed.
Failed Augmentin and acyclovir by PCP for “infected paronychia”
Exam notes an ulcerated lesion and regional adenopathy
TularemiaHistory
McCoy & Chapin 1910 “plague-like disease”
of rodents in Tulare Co. CA
Bacterium Tularense Edwards Francis
1928 - 800 cases isolated organism proved vector
named the diseasedeveloped culture and serology methodsnoted risk to workers
Parola, Clin Infect Dis 2001 Mar 15;32(6):897-928
TularemiaTularemiaEpidemiologyEpidemiology
1368 cases 1990-20001368 cases 1990-2000 All states except Hawaii, All states except Hawaii,
but predominately MO, but predominately MO, AK, OK & SDAK, OK & SD
Reinstated on nationally Reinstated on nationally notifiable list 2000 notifiable list 2000 (n=142)(n=142)
Type A (biogroup Type A (biogroup tularensis)tularensis)
Multiple vectors (tick, Multiple vectors (tick, deerfly)deerfly)
>250 animal species>250 animal species rabbitsrabbits hareshares muskratsmuskrats
Other transmissionOther transmission carnivorescarnivores direct contactdirect contact inhalation/ingestioninhalation/ingestion
Peak incidence 1939Peak incidence 1939
Outbreak 2001 Pneumonic Tularemia
15 patients 11 primary pulmonary 1 death
Outbreak 2001 Pneumonic Tularemia
Figure 1. Cases of Primary Pneumonic Tularemia, Tularemia with No Localizing Signs, and Ulceroglandular Tularemia on Martha's Vineyard, May 21 through October 28, 2000, According to the Week of Onset of Illness.
Feldman et al, N Engl J Med 2001 Nov 29;345(22):1601-6
TularemiaTularemiaClinical ManifestationsClinical Manifestations
UlceroglandularUlceroglandular
black based ulcerblack based ulcer
tender regional tender regional
lymphadenopathy lymphadenopathy
bubobubo
TyphoidalTyphoidal
OculoglandularOculoglandular
Primary pulmonaryPrimary pulmonary
TularemiaTularemiaDiagnosisDiagnosis
TitersTiters
4-fold increase4-fold increase
single > 1:160single > 1:160
Skin testSkin test
Culture – notify Culture – notify
laboratorylaboratory
TularemiaTularemiaTreatmentTreatment
Streptomycin 1 gm iv q12h for 10 daysStreptomycin 1 gm iv q12h for 10 days
Gentamicin 5 mg/kg/d for 10 daysGentamicin 5 mg/kg/d for 10 days
Tetracycline/chloramphenicolTetracycline/chloramphenicol associated with 15-20% relapseassociated with 15-20% relapse
QuinolonesQuinolones Excellent in vitro activityExcellent in vitro activity Limited data, anecdotal experience suggests efficacyLimited data, anecdotal experience suggests efficacy
Live attenuated vaccine for high risk groupsLive attenuated vaccine for high risk groups
TularemiaTularemiaComplicationsComplications
Pneumonia Pneumonia
abscess, effusionabscess, effusion
RhabdomyolysisRhabdomyolysis
Acute renal failureAcute renal failure
MeningitisMeningitis
PericarditisPericarditis
Clinical vignette
27yo WM hiker spends a week in the Rocky Mtns in a cabin.
Last day of trip develops fever, chills, HA, myalgias
Resolves in 3 days, then recurs 7 days later
Tick-borne Relapsing Fever
Dutton et al- Described tick relapsing fever, caused by Borrelia duttonii and transmitted by Ornithodoros moubata in W. Africa
13 species of Borrelia genus Ornithodoros
Noctural feeder Short attachment Usual hosts small mammals
Worldwide, but only Western US Occurs in cabin-dwellers
Parola, Clin Infect Dis 2001 Mar 15;32(6):897-928
Tick-borne Relapsing Fever
acute onset of high fever with chills, headache, myalgia, arthralgia, and coughing
Hemorrhage, iritis or iridocyclitis, hepatomegaly, or splenomegaly
rash at the end of the first febrile episode
•neurological findings
•B. turicatae (U.S.)
•B. duttonii (Africa)
•Jaundice ( 7%)
•case-fatality rate 2%-5%
•Primary episode 3 days
•Mean period between episodes 8 days
Tick-borne Relapsing Fever
Borreliae in peripheral
blood of febrile patients.
Sensitivity 70% (darkfield microscopy or Giemsa or Wright's
stain). Quantitative buffy coat Serology not useful PCR
Jarisch-Herxheimer reaction
•doxycycline (Penicillin, erythromycin, or
ceftriaxone)
Clinical vignette
23 yo WF vacationer on Long Island develops fever, malaise, and circular rash on her arm
Lyme
Most commonly reported tick-borne infection in U.S.
1993-1997, mean 12,451 annual cases (CDC)
LymeHistory
Cluster of cases near Lyme, CT 1975
Johnson RC, Schmid GP, Hyde FW, Steigerwalt AG, Brenner DJ. Borrelia burgdorferi sp. nov.: etiological agent of Lyme disease. Int J Syst Bacteriol 1984; 34:496 7.
Lymeepidemiology
B. burgdorferi sensu lato
Tick vector Black-footed mouse
reservoir White-tailed deer host Birds and mammals
implicated in Europe
Lyme DiseaseLyme DiseaseEarly ManifestationsEarly Manifestations
Erythema migrans Erythema migrans (90%)(90%) Occurs 8-14 days after Occurs 8-14 days after
bitebite Single lesion, average Single lesion, average
size 15cmsize 15cm Systemic symptoms Systemic symptoms
may be presentmay be present Secondary lesions may Secondary lesions may
occuroccur
CarditisCarditis Aseptic meningitisAseptic meningitis Bell’s palsyBell’s palsy
Lyme DiseaseLyme DiseaseLate ManifestationsLate Manifestations
ArthritisArthritis Knees involved in 90%Knees involved in 90% Usually resolves, 1-2 weeksUsually resolves, 1-2 weeks May recurMay recur
CNS disease (rare in children)CNS disease (rare in children)
Lyme DiseaseLyme DiseaseDiagnosisDiagnosis
SerologySerology ELISAELISA Western blotWestern blot
Culture on BSK-II Culture on BSK-II mediamedia 57-85% sensitive skin57-85% sensitive skin Blood, CSF, synovial Blood, CSF, synovial
fluidfluid
Warthin-Starry stainWarthin-Starry stain
PCRPCR
Lyme DiseaseLyme DiseaseTreatment of Early DiseaseTreatment of Early Disease
Doxycycline ( Doxycycline ( 8 years of age) 8 years of age)
AmpicillinAmpicillin
Penicillin allergic: cefuroxime axetil or Penicillin allergic: cefuroxime axetil or
erythromycinerythromycin
Duration 14 - 21 daysDuration 14 - 21 days
Lyme DiseaseLyme DiseaseTreatment-Disseminated & Late DiseaseTreatment-Disseminated & Late Disease
Multiple skin lesionsMultiple skin lesions Oral, 21 daysOral, 21 days
Isolated facial palsyIsolated facial palsy Oral, 21 -28 daysOral, 21 -28 days
ArthritisArthritis Oral, 28 daysOral, 28 days
Persistent arthritisPersistent arthritis Parenteral, 14 - 21 daysParenteral, 14 - 21 days
CarditisCarditis Parenteral, 14 - 21 daysParenteral, 14 - 21 days
CNSCNS Parenteral, 14 - 21 daysParenteral, 14 - 21 days
Does Lyme Disease Exist Does Lyme Disease Exist in Texas?in Texas?
Southern Tick-Associated Rash Illness (STARI)
Similar EM rash Long-term and serious
complications not reported
Responds to doxycycline Organism by PCR B.
lonestari No culture 639 cases in Texas 1986-
1996
Lyme-Like Disease in MissouriLyme-Like Disease in Missouri
ECM - YesECM - Yes Serology - usually Serology - usually
negativenegative Complications - RareComplications - Rare Vector - Lone star tickVector - Lone star tick Etiologic agent - variant Etiologic agent - variant
Borrelia species (?)Borrelia species (?) Protection from vaccine - Protection from vaccine -
UnknownUnknown
Tick-Transmitted DiseasesTick-Transmitted DiseasesPreventionPrevention
Avoid tick-infested areasAvoid tick-infested areas
Wear protective clothing that covers exposed areasWear protective clothing that covers exposed areas
Use DEET - containing insect repellantsUse DEET - containing insect repellants
Spray permethrin on clothesSpray permethrin on clothes
Remove attached ticks promptly Remove attached ticks promptly Do not squeezeDo not squeeze
Clinical Vignette
47yo outdoor construction worker in Massachusetts presents with 1 week of fever, chills, DOE in June.
PMH is significant for splenectomy due to trauma.
Lab calls reporting strange finding on blood smear.
Babesiosis
Babesia microti (Europe B. divergens) Worldwide distribution Primary host white-footed mouse
Peromyscus leucopus
Usually tick-borne Can be transfusion-related
Babesiosis
Clinical Features: Most infections asymptomatic fever, chills, sweating, myalgias, fatigue, hepatosplenomegaly, and
hemolytic anemia. incubation period of 1 to 4 weeks more severe in immunosuppressed, splenectomized, and/or elderly. B. divergens tend to be more severe usually occurs.
Laboratory Diagnosis: thick and thin blood smears (Giemsa)
Treatment: clindamycin plus quinine or atovaquone plus azithromycin exchange transfusion has been used in severely ill patients with high
parasitemias.
Infection with Babesia. Giemsa-stained thin smears. Note in B the tetrad (left side of the image), a dividing form pathognomonic for Babesia. Note also the variation in size and shape of the ring stage parasites and the
absence of pigment.
Babesia microti infection, Giemsa-stained thin smear. The organisms resemble Plasmodium falciparum; however Babesia parasites present several distinguishing features: they vary more in shape and in size; and
they do not produce pigment.
Clinical Vignette
48 yo male presents with acute onset episodic fever abdominal pain, headache, myalgias and nausea/vomiting, then profuse sweats.
Recent trip to Thailand looking for exotic bird species.
Exam notes tender right and left upper quadrant and splenomegaly
Labs note pancytopenia
Malaria
300–500 million infections worldwide and approximately 1 million deaths annually (CDC)
Plasmodium falciparum, P. vivax, P. ovale, or P. malariae
infected female Anopheles mosquito
blood transfusion or congenital
Fatal cases are due to falciparum (“knobs”)
P. vivax and P. ovale parasites can persist in the liver (natural infection only)
P. malariae acute illness rare in normal hosts, causes chronic infection (GN)
Malaria
Chloroquine-susc Dominican Republic,
Haiti Central America west
of the former Panama Canal Zone
Egypt some countries in the
Middle East
mefloquine resistance borders of Thailand with
Burma (Myanmar) and Cambodia
western provinces of Cambodia eastern states of Burma
(Myanmar) Fansidar resistance
Amazon River Basin area of South America,
Southeast Asia other parts of Asia large parts of Africa
Malaria
fever and influenzalike symptoms chills, headache,
myalgias, and malaise Classic paroxysm
Chill Spike Sweat
can occur at intervals Falciparum less exact Vivax/ovale tertian Malariae quartian
anemia and jaundice, seizures, mental confusion kidney failure, coma, and
death 6 days after initial exposure
to several months after chemoprophylaxis
MalariaDiagnosis
Peripheral smear Vivax/ovale Falciparum
No mature forms High parasitemia
(directly related to mortality in nonimmune)
Multiple ring forms/cell Infects all ages
Hypoglycemia Lactic acidosis Hemolysis Acute renal failure Pancytopenia
MalariaTreatment
Hospitalize if nonimmune and suspect falciparum
Different drug than prophylaxis
Halofantine cross resistant w/mefloquine
Start 2nd drug later
If vivax/ovale need Primaquine
Artemisin if mefloquin/cholorquine resistance
Exchange transfusion if parasitemia >15% in nonimmune
Malaria Prevention
transmission occurs primarily between dusk and dawn
well-screened areas, mosquito nets, clothes that cover
DEET (N,N-diethylmetatoluamide)
pyrethroid-containing flying-insect spray in living and sleeping areas
Chemoprophylaxis
mefloquine or chloroquine 1–2 weeks before doxycycline and atovaquone/proguanil 1–2 days
before continuously while in malaria-endemic areas 4 weeks (chloroquine, doxycycline, or mefloquine)
after 7 days (atovaquone/proguanil) after Terminal prophylaxis with Primaquine final 14 days
fatal hemolysis in those who are G6PD deficient
Chemoprophylaxispregnancy
Long history of chloroquine and quinine use Data supports safety of mefloquine in 2nd an
3rd trimester Data in first trimester sketchy, patient must
weigh risks No Doxycycline or Primaquine No data for Malarone
Malaria
Persons who have been in a malaria risk area, either during daytime or nighttime hours, are not allowed to donate blood for a period of time after returning from the malarious area. Residents of nonmalarious countries are not allowed to donate
blood for 1 year after they have returned from a malarious area. Persons who are residents of malarious countries are not
allowed to donate blood for 3 years after leaving a malarious area.
Persons who have had malaria are not allowed to donate blood for 3 years after treatment for malaria.
Malaria Information
http://www.cdc.gov/travel Voice information service 1-877-FYI-TRIP CDC Malaria Hotline (770-488-7788) from 8:00
a.m. to 4:30 p.m. Eastern time CDC Emergency Operation Center at 770-488-7100
page person on call for the Malaria Epidemiology Branch.
Clinical Vignette
72 yo WM alcoholic with CAD presents with 3 day h/o fever, myalgias, headache followed by acute onset confusion and tremulousness
Works as a nursery sales rep and travels frequently to East Texas
No improvement on levaquin EKG afib CSF notes elevated protein and lymphocytic
pleiocytosis
Viral Encephalitisarthropod-borne
Alphaviridae Eastern Equine Western Equine
BunyaviridaeLaCrosse
FlaviviridaeSt. Louis
Powassan (ticks)
Japanese
Tick-borne (ticks)
West Nile
Culex
SLE Human CasesSLE Human Cases
EEE Equine CasesEEE Equine Cases
EEE Human CasesEEE Human Cases
SLE Avian CasesSLE Avian Cases
EEE Mosquito PoolsEEE Mosquito Pools
WNV Equine CasesWNV Equine Cases
WNV Human CasesWNV Human Cases
WNV Avian CasesWNV Avian Cases
SLE 5 Human CasesSLE 5 Human Cases
Outbreak or Cluster with Human Case(s)
Arboviral ActivityArboviral Activity Louisiana Louisiana
20012001
Eastern Equine
Eastern US Ave. 4
cases/year Togaviridae,
genus Alphavirus
35% mortality 35% permanent
neuro defect
St. Louis Encephalitis
Aseptic meningitis or encephalitis Majority subclinical or mild illness Intermittent epidemic transmission - up to 3,000
cases per year (1975) Culex mosquitoes Elderly - biological risk factor Low SES areas - environmental risk factor Outdoor occupation - exposure risk factor
St. Louis Encephalitis
Largest outbreaks in 15 years occurred in 1990 Urban transmission in west first recognized in 1987 Deterioration of inner cities, global warming may
increase vector abundance and transmission Unpredictable and intermittent occurrences of
outbreaks Multiple environmental, biological and social
factors contributing to disease occurrence Virus maintenance and overwintering cycle
La Crosse Encephalitis
Frank encephalitis progressing to seizures, coma majority subclinical or mild 70 cases/year Case-fatality ratio <1% Social costs from adverse effects on IQ and school performance woodland habitats in treehole mosquito (Aedes triseriatus) and
vertebrate hosts (chipmunks, squirrels); survives winter in mosquito
Vector uses artificial containers (tires, buckets, etc.) in addition to treeholes
La Crosse Encephalitis
Children <16 years old: biological risk factor Residence in woodland habitats environmental risk
factor Containers at residence environmental risk factor Outdoor activities: behavioral risk factor Traditional endemic foci in the great-Lakes states Increased case incidence in mid-Atlantic states Rural poor most affected Disease is considerably under-reported
West Nile Virus
• First isolated from a febrile adult woman in the West Nile District of Uganda in 1937
• Ecology was characterized in Egypt in the 1950s.
• Cause of severe human meningoencephalitis in elderly patients during an outbreak in Israel in 1957
• Equine disease first noted in Egypt and France in early 1960s.
• Outbreak of West Nile-Like Viral Encephalitis -- New York, 1999. MMWR, 1999:48(38);845-9
• Update: West Nile-Like Viral Encephalitis -- New York, 1999. MMWR, 1999:48(39);890-2
West Nile Virus in the U. S. 2005
Clinical Epidemiology
Incubation period 3 - 14 days 20% develop “West Nile fever” 2006 to date: 2171 cases, 74 deaths in U.S. 1 in 150 develop meningoencephalitis
Advanced age primary risk factor for severe neurological disease and death
West Nile Fever: Classic Clinical Description
• Mild dengue-like illness of sudden onset
• Duration 3 - 6 days
• Fever, lymphadenopathy, headache, abdominal pain, vomiting, rash, conjunctivitis, eye pain, anorexia
• Symptoms of West Nile fever in contemporary outbreaks not fully studied
West Nile Fever: Classic Clinical Description
Symptoms of Hospitalized Patients withWest Nile Virus, New York City, 1999
2%Lymphadenopathy
19%Rash
27%Diarrhea
46%Change in mental status
47%Headache
51%Vomiting
53%Nausea
56%Weakness
90%Fever
Neurological Presentations of West Nile Virus Infection
New York City 1999 Encephalitis/meningoencephalitis 62% Meningitis 32% Complete flaccid paralysis 10%
Confused with Guillain-Barre syndrome EMG and nerve conduction velocity-both axonal and demyelinating lesions,
with axonal lesions most prominent
Preliminary data 2002 Complaints of weakness out of proportion to exam Myoclonus nearly a universal finding Some patients have Parkinsonian
Previous series Ataxia, extrapyramidal signs, cranial nerve abnormalities, myelitis, optic
neuritis, seizures
West Nile Virus
489 WNV-viremic donors as of 9/16/03 two cases of blood transfusion-associated
WNV in 2003, (TX and Nebraska). Both encephalitis and are recovering.
In 2003, all blood banks started screening for West Nile virus and will not take donations from people w/fever and headache in the week prior
1999 and 2000 Serosurvey Results
Location Participants PositivesSeroprevalence
(%)
NYC 1999
Queens677 19 2.6
NYC 2000
Staten Is.871 4 0.46
NYS 2000
Suffolk Co.834 1 0.12
CT 2000
Fairfield Co.731 0 0.0
Clinical Vignette
59 yo Mexican immigrant admit with 3 month history of progressive shortness of breath, PND, orthopnea, LE edema
Chagas’ Disease
American trypanosomiasis (Trypanosoma cruzi)
16-18 million people are infected 50,000 will die each year. poorly constructed houses found in the
rural areas of the above-mentioned countries are at elevated risk of infection. Houses constructed from mud, adobe, or thatch present the greatest risk.
Chagas’ Disease
Reduviid bugs, or "kissing bugs"
South and Central America
deposits feces on a person's skin at night
rubs the feces into the bite wound, an open cut, the eyes, or mouth.
Transplacental, congenital or breastfeeding.
By blood transfusion By eating uncooked food
contaminated feces of "kissing bugs."
early stage of infection (acute Chagas disease) usually is not severe, but can be fatal in infants.
1/3 chronic after 10-20 years.
average life expectancy decreases 9 years.
Chagas’ Disease
Acute: 1% of cases. Romaña's sign fatigue, fever, enlarged
liver or spleen, and swollen lymph glands.
rash, loss of appetite, diarrhea, and vomiting occur. In
infants and in very young children cerebral edema
symptoms last for 4-8 weeks.
Indeterminate (asymptomatic)
Chronic: Cardiac problems, including
an enlarged heart, altered heart rate or rhythm, heart failure, or cardiac arrest are symptoms of chronic disease.
enlargement of parts of the digestive tract, which result in severe constipation or problems with swallowing.
immune compromised, including persons with HIV/AIDS, Chagas disease can be severe.
Clinical Vignette
September 9, 1981, a 72-year-old male from Edinburg, Texas, developed fever and weakness 16 days after being bitten by tsetse flies during a hunting trip in northwest Tanzania. Several days after onset of fever, he noticed a raised, tender, erythematous nodule (6-8 cm in diameter) on the posterior aspect of his right arm.
East African Trypanosomiasis
six patients have shared several characteristics: exposure to infected tsetse flies while visiting game parks in
eastern or southern Africa, development of acute, febrile illness consistent with
Trypanosoma brucei rhodesiense infection 1-21 days after visiting
detectable typanosomes on peripheral blood smears, and recovery after appropriate therapy. Only two of the five earlier cases showed clear evidence of
central nervous system (CNS) involvement; both patients had elevated CSF protein, increased CSF cell count, and trypanosomes in the CSF.
East African Trypanosomiasis
Suramin is recommended for hemolymphatic stage does not cross the blood-brain barrier, Melarsoprol, (relatively toxic) +/- suramin when infection
involves the CNS trypanosomes are observed in the CSF morula cells of Mott or an elevated CSF IgM is strongly
suggest CNS involvement elevated CSF cell count usually should be monitored for CNS involvement during
treatment and at regular intervals for 1-2 years thereafter
Clinical Vignette
36 yo WF presents with nonhealing lesions on face for several months
Frequent travel to Caribbean and Mexico Recent pregnancy complicated post-partum
by acute cholecystitis
Leishmaniasis
Sand fly vector factors determining the form : species,
geographic location, and immune response of the host.
Cutaneous leishmaniasis one or more lesions raised edge and central crater. painless or painful. Regional lymphadenopathy
visceral leishmaniasis fever, weight loss, and an enlarged
spleen and liver (usually the spleen is bigger than the liver).
lymphadenopathy. pancytopenia opportunistic infection in areas where it
coexists with HIV.
Leishmaniasis
Leishmaniasis
Diagnosis: biopsy
Treatment: stibogluconate (per CDC) (see Medical Letter)
Don’t forget
Dengue Plague Yellow fever Onchocerciasis Loaiasis West African
Trypanosomiasis
Typhus Endemic Scrub