emerging infectious diseases 2016: menace of the...
TRANSCRIPT
Emerging Infectious Diseases 2016:
Menace of the Mosquito
Infectious Diseases & Emergency Medicine Washington University School of Medicine No disclosures
October 13, 2016
Define what is an emerging infectious disease, how they come about, and why they matter in prehospital care. Update providers on current clinical knowledge & approach to Chikungunya and Zika virus infection.
Zoonoses
SARS coronavirus (civet, bat)
Nipah virus (bat)
Avian influenza (poultry)
2009 H1N1 influenza (pig)
MERS coronavirus (camel)
Ebola virus (bat, monkey)
Vector-borne diseases West Nile virus (mosquito)
Chikungunya virus (mosquito)
Zika virus (mosquito)
(Can also be zoonoses)
• War • Famine • Poverty & social inequality • Lack of political will
• Climate & weather • Economic development
Intent to harm
Changing ecosystem
Cohen. Nature 2000;406:762.
2015: U.S. & foreign air carriers transported 196.3 million passengers between the U.S. & the rest of the world
Europe: 56.3 million
C. America: 33.7 million
Asia: 28.8 million
www.transportation.gov
U.S.
Arbovirus Alphavirus
Single-stranded RNA Vector-borne Swahili/Makonde: “to walk bent over”
Incapacitating arthralgias Can look like dengue
Traditionally a tropical disease
http://phil.cdc.gov/
Excluding countries/territories w/ only imported cases
As of April 22, 2016 http://www.cdc.gov/chikungunya
• Endemic to parts of W. Africa • 2005-6: Réunion Island • 2007: Italy • 2013: Caribbean (St. Martin)
2013 – present
http://www.paho.org/chikungunya
Local transmission: • Late 2013:
Caribbean • Early 2014:
Florida, Puerto Rico, U.S. Virgin Islands
• Since 2014: 45 countries/ territories
• >1.7 million suspected cases reported
2006-2013: 28 cases/yr 2014: 2,799 cases
http://www.cdc.gov/chikungunya
Florida (2014): 11 locally-transmitted cases
2014
http://www.cdc.gov/chikungunya
2016
93 cases (CONUS), 137 (P.R.) As of October 11, 2016
• Asian tiger mosquito • Mostly outdoors (garden) • Aggressive biter
• Yellow fever mosquito • Indoors & outdoors • Sneaky biter
http://www.cdc.gov/chikungunya
Life cycle Infected pts spread virus via travel
Europe: Indian Ocean islands, India, Malaysia N. America: Caribbean, S. America
Competent vectors + seasonal synchrony = local transmission Nosocomial transmission: blood, corneal grafts Vertical transmission (mother-fetus):
Reunion Island epidemic (48.7%)
Curr Opin Virol 2011;1(4):310-7.
Monkeys, rodents, birds, other vertebrates Human (epidemics)
Incubation period: 2-4 d (range 1-14) Fever Polyarthralgias (2-5 d after onset of fever)
Intense, disabling Often ≥ 10 joint groups Often symmetrical Distal > proximal
Polyarthralgia (96%) %
Ankle 66.2
Knee 60.9
Metacarpophalangeal joints 49.6
Metatarsal joints 41.0
Shoulder 36.4
Elbow 31.7
Wrist 29.1
Sternoclavicular joints 15.0
Hip 7.2
157 pts, Réunion Island (2005-6) Clin Infect Dis 2007;44:1401-7
Maculopapular rash (50%; ≥3d after onset of fever)
Pruritus, bullous dermatitis (children)
Headache, conjunctivitis, myalgias, N/V Swollen joints (ankle, MTP, wrist, MCP)
Lymphopenia, thrombocytopenia, elevated liver enzymes Symptoms typically resolve within 7-10 d Rarely life-threatening (<0.1%)
Meningoencephalitis Cardiovascular, respiratory, renal failure
J Am Acad Dermatol 2008;58:308-16.
Lancet Infect Dis 2007;7:319-27.
Lancet Infect Dis 2007;7:319-27.
Chronic sequelae Polyarthralgias (previously affected joints) Polyarthritis Tenosynovitis
Wrist, hand, ankle Carpal tunnel syndrome
New-onset Raynaud phenomena
Chikungunya: “that which bends up”
Polyarthritis of hands & tenosynovitis of wrists Indian J Dermatol 2010;55(1):54-63.
Clinical features Chikungunya Dengue Fever (>38.9°C) +++ ++ Myalgias + ++ Arthralgias +++ +/– Headache ++ ++ Rash ++ + Bleeding dyscrasias +/– ++ Shock – +/– Leukopenia ++ +++ Neutropenia + +++ Lymphopenia +++ ++ Thrombocytopenia + +++
Dengue
Clin Infect Dis 2009;49:942-8
Retro-orbital
Malaria Typhoid fever Rickettsial infection Leptospirosis Other Alphaviruses (e.g., Ross River, O’nyong nyong)
Measles, Rubella, EBV Meningococcemia Seronegative rheumatoid arthritis
Viral DNA in blood RT-PCR (first 5-8 days)
Antibodies to CHIKV in blood IgM ELISA (D5 → D90) IgG ELISA (D14 → years)
Isolation of virus in culture Testing via local/state health dept, CDC
Supportive care Rest, fluids, antipyretics NSAIDs, other analgesics
No effective antivirals Ribavirin & interferon-α (in vitro activity against replication)
Infection → long-standing protective immunity
Fevers, polyarthralgias (distal joints), rash Rarely life-threatening
Unlike dengue! Arthralgias can persist A. aegypticus & albopictus mosquito
CHIKV
Flavivirus Dengue virus Yellow fever virus West Nile virus
Enveloped Single-stranded, positive-sense RNA Vector-borne
Arthropod (arbovirus) Aedes mosquito
Isolated in 1947 Rhesus monkey Zika Forest (Uganda)
Confined to Africa & Asia for 60 years
Sporadic cases (14 reported) Seroprevalence
First documented outbreak (2007)
Yap State (Micronesia)
(2007) Rash, fever, conjunctivitis, arthralgia 185 cases
49 confirmed (RNA, neutralizing antibody response)
59 probable (IgM by ELISA)
No admissions or deaths
Overall attack rate: 14.6 per 1,000 residents
Duffy et al. N Engl J Med 2009;360:2536.
Population (2000): 7,391
(2007-14)
Yap (2007) Est. 5,400 cases (73% population; >900 illnesses)
French Polynesia (2013-14) Est. 28,000 cases
(11% population)
New Caledonia (2014) 114 cases Easter Island (2014)
>50 confirmed cases
Imported cases: • Asia • Australia • Europe • U.S.
Brazil May 2015: 1st local case September 2015: microcephaly (northeast areas) Early est. 440,000 – 1,300,000 suspected cases
(2015 – present)
Mid July 2015
Late October 2015
February 2016
February 1, 2016: WHO: Public Health Emergency of International Concern (PHEIC)
February 3, 2016: CDC: Emergency Operations Center – Level 1
www.cdc.gov/zika
Travel-associated: 3,712 Locally-acquired: 105
As of 10/5/2016
U.S. territories: Travel-associated: 83 Locally-acquired: 24,118
Local transmission since mid-July 2016
Vector: Aedes spp. A. aegypti A. albopictus A. africanus A. hensilli & others
Non-vector: (blood, urine, semen, saliva, CSF, amniotic fluid, breast milk)
Sexual transmission Vertical transmission (intrauterine/intrapartum) Blood transfusion Not yet tied to breastfeeding
Yap (2007) Macular/papular rash 90% Fever (usually low-grade) 65% Arthritis/arthralgia (hands/feet) 65% Non-purulent conjunctivitis 55% Myalgia 48% Headache 45% Retro-orbital pain 39% Edema 19% Vomiting 10%
Incubation period: 2-14 days after bite Up to 80% cases are asymptomatic Mild, self-limited illness (2-7 days)
Pregnancy not associated w/ ↑risk or severity
Severe disease uncommon
Low case fatality
Duffy et al. N Engl J Med 2009;360:2536.
Zanluca et al. Mem Inst Oswaldo Cruz 2015;110(4):569.
http://exanthem.dermnetnz.org/viral/zika.html
Guillain-Barre syndrome (French Polynesia, S. America)
Progressive, mostly symmetric muscle weakness Absent/depressed deep tendon reflexes Mild to complete paralysis (extremity, face, respiratory, bulbar); death (rare)
San Salvador, El Salvador
Head circumference ≥2 S.D. below mean
Sex, gest. age at birth Highest risk if infected during 1st trimester
Bahia, Brazil: 0.88-13.2% Associated findings:
Brain calcifications Ventricular enlargement Macular & optic nerve lesions
Johansson et al. N Engl J Med 2016;375:1.
Dengue Chikungunya Malaria Leptospirosis Rickettsia Group A Strep Measles Parvovirus Rubella Other viruses
Clinical feature DENV CHIKV ZIKV Fever ++++ +++ +++
Myalgia/arthralgia +++ ++++ ++
Edema of extremities 0 0 ++
Maculopapular rash ++ ++ +++
Retro-orbital pain ++ + ++
Conjunctivitis + +++
Lymphadenopathy ++ ++ +
Hepatomegaly +++ 0
Leukopenia/ thrombocytopenia
+++ +++ 0
Hemorrhage + 0 0 Ioos et al. Med Mal Infect 2014;44:302.
ZIKV
Viral DNA in serum/urine RT-PCR (first 3-7 days)
Antibodies to ZIKV IgM Neutralizing antibody titers (≥4-fold higher than DENV titers) Detectable ≥4 days of symptoms
Cross-reactivity w/ other flaviviruses (e.g., DENV, CHIKV, YFV, WNV)
Testing via local/state health dept, CDC https://health.mo.gov/living/healthcondiseases/communicable/zika.php
Supportive care Rest Fluids Fever/pain control (acetaminophen)
Avoid ASA/NSAIDs until DENV ruled out due to bleeding risk
No antivirals No vaccine After infection → immunity
Primarily mosquitoes Incubation: 2-14 days Fever, rash, arthralgias
Self-limited Assoc w/ microcephaly Symptoms & travel history should guide testing Guidelines still evolving!
Approach & Prevention
Identify: Testing for Chikungunya:
Acute infection Test for Zika:
Acute infection (≥1 symptom) + exposure (travel, sex) within 14 days of symptom onset Asymptomatic pregnant woman + exposure within the past 12 weeks
Isolate?: Not necessary!! Inform: Notify local/state health dept PPE: Standard precautions only
Avoid travel to areas w/ active transmission Minimize mosquito exposure
Insect repellants (DEET, picardin, ELO/PMD, IR3535)
Sunscreen, then repellent DEET can ↓SPF by 30%
Long sleeves & pants Permethrin-treated
Bed nets Screens, AC – stay indoors
Protect infected pts from mosquitoes (1-3 wks!) to ↓ local transmission Vector control
Eliminate breeding sites Containers are ideal larval habitats Empty standing water
Larvicides The future
Vaccine???
www.paho.org
Reduce risk for sexual transmission If exposed, avoid unprotected sex & unintended pregnancy:
Men: minimum 6 months Women: minimum 8 weeks
Pregnant women w/ male partners who have or are at risk for ZIKV infection
Condoms or abstinence for the duration of the pregnancy
Tale of 2 emerging mosquito-borne illnesses: Chikungunya & Zika Virus
Understand & mitigate exposure: Geography matters – get a brief travel history!
CDC, WHO, ProMED mail Know when & how the disease is transmitted
Hosts, vectors Refer for testing when indicated
Prevention is key!