2/21/2014
Emerging and Re-emerging infections from the North American Wild Sukhjit S. Takhar, MD Brigham and Women’s Hospital Harvard Medical School
Hantavirus and More
1 2/21/2014
Objectives
• Hantavirus • Plague • Rocky Mountain Spotted Fever • Rabies
Would you rather have?
• Hantavirus • Plague • Rocky Mountain Spotted Fever • Rabies
2 2/21/2014
48 year old male 3 days of influenza-like symptoms Shortness of breath Back country hiking and camping 7 days ago in Yosemite
Hantavirus Pulmonary Syndrome
Sin Nombre virus
3 2/21/2014
Hantavirus
• Severe hemorrhagic fever with renal syndrome • Hantavirus pulmonary syndrome
Hantavirus in Yosemite
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Hantavirus in the US
• 1993 – 24 patients with severe pneumonia – 75% case fatality rate
6 2/21/2014
Hantavirus
• Parasites of rodents and insectivores • Reservoir of Hantavirus (SNV): Deer Mouse – Cotton and rice rats (south east)
Transmission
• Breath air contaminated with virus – Rodent urine – Rodent droppings – (contaminated food, bites, etc…) • Incubation period: 1 to 6 weeks • HPS does not have person to person transmission
7 2/21/2014
Clinical Case Definition
• Febrile illness with interstitial edema (ARDS) in a previously healthy individual – Fever, headaches, muscle aches – Pulmonary edema
Clinical Manifestations
1. Fevers, chills, myalgia, headaches 2. Pulmonary vascular permeability 3. Shock
8 2/21/2014
Laboratory Abnormalities
• Hemo-concentration • Leukocytosis – Bandemia – Atypical lymphocytes • Thrombocytopenia
Diagnosis
• Rural rodent exposure? – Influenza like illness? – Shortness of breath?
9 2/21/2014
Treatment
• Supportive care • Antibiotics until confirmatory testing • Analgesics and antipyretics
Could it be?
• Zoonosis from rats? – Plague? • Tick Borne? – Tularemia? • Infectious pneumonia • Sepsis
10 2/21/2014
Plague
Yersinia pestis
11 2/21/2014
History of Plague
• Black death • Late Middle Ages ~1347-1350 – 75 million – 200 million deaths – Killed 1/3 of the human population
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Pathogenesis
• An Infection of Rodents and Fleas – Fleas feed on bacteremic hosts (often a rodent) – Feed on other rodents and transmit the disease
Transmission
• Bite from an infected flea (or rarely other animals) • Direct contact with contaminated tissues • Rarely, inhalation of respiratory section • Short Incubation (1-6 days)
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Clinical Manifestations
• Bubonic Plague • Septicemic Plague • Pneumonic Plague
Oregon case
14 2/21/2014
Bubonic Plague
• Fevers, chills, weakness • Regional Lymphadenitis (Buboes) • Often the first stage of the disease
Treatment
• Fatal cases are associated with delays in diagnosis and treatment – Aminoglyocoside – Fluoroquinolones – Tetracyclines
15 2/21/2014
Plague
• Report to state health department • Consider bioterrorism • Antibiotic prophylaxis
Plague in Yosemite
16 2/21/2014
Could it be?
• Anthrax? • Tularemia?
17 2/21/2014
Rocky Mountain Spotted Fever
Rickettsia rickettsii
Rocky Mountain Spotted Fever
• Vector: Hard Ticks (dog ticks) • Incubation period (2 – 14 days) • Untreated mortality: 20-87% • Needs to be attached for at least 4-6 hours
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Rocky Mountain Spotted Fever
• North Carolina • Oklahoma • Arkansas • Tennessee • Missouri
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Risk Factors
• Exposure to the tick vector – Exposure to dogs – Wooded area – Peaks in summer months
Clinical Presentation
“A febrile disease, characterized clinically by a continuous moderately high fever, and a profuse or purpuric eruption in the skin, first appearing on the ankles, wrists, and forehead, but rapidly spreading to all parts of body.”
20 2/21/2014
RMSF
• Clinical Triad: Fever, Rash, and Headache is only present 3% early in disease • Consider the disease with fever and headache • Rash appears 2-5 days after onset of fever • Innoculation eschar is rare
Diagnosis
•History • Physical Examination • Epidemiological Data • Then laboratory confirmation
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Tick Removal
• Fine-tipped tweezers to grasp tick • Pull upward • Clean wound • Do not use nail polish, petroleum jelly, or heat
Treatment
• Treated Mortality 5% • Tetracyclines and Chloramphenicol – Doxycycline in Children is ok for this!
22 2/21/2014
Other things to think about…
• Meningiococcemia • Tick Borne Rickettsial disease – Anaplasmosis – Erlichiosis • Other Tick Borne Diseases – Tularemia?
23 2/21/2014
Rabies
Rhabdovirdae
Rabies
• Epidemiology of human rabies reflects local animal rabies • Developing countries: Dogs • United States: Bats and rabid wild animals
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Rabies
• Neurotropic viral infection transmitted from a bite of an infected animal • Travels to CNS • Acute, progressive encephalomyleitis • Incubation 1-3 months (days – years) • Highest case fatality ratio of any infectious disease if untreated
Rabies
• 92% of reported cases of rabies in 2010 were in wild animals • Wild carnivores and Bats – Racoons 36.5% – Skunks 23.5% – Bats 23.2% – Foxes 7.2%
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Rabies
• Bites, scratches, or mucous membrane exposures to bat • Clustering of human cases with bat exposures have never been reported
Wound Management
• Clean the wound – Soapy water – Betadine • Protective effect of wound care may be as important as vaccination
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Postexposure Prophylaxis
• Rabies Immunogloblin (RIG) + Rabies Vaccination • 2010 CDC Guidelines – Reduced (4-dose) regimen – Improved from the Semple Vaccine • (Daily injections of 5-10 ml) into abdominal wall)
Rabies
• Survival from clinical rabies is extremely rare • Consider rabies in patients with progressive encephalitis • Avoid wildlife • Prompt PEP
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Selected References
• Rhee, D. K., Clark, R. P., Blair, R. J., Katz, J. T., & Loscalzo, J. (2012). Breathtaking Journey. New England Journal of Medicine, 367(5), 452-457. • Hantavirus, C. D. C. (2012). Atlanta, GA: US Department of Health and Human Services, CDC; 2012. • Perry, Robert D., and Jacqueline D. Fetherston. "Yersinia pestis--etiologic agent of plague." Clinical microbiology reviews 10.1 (1997): 35-66.
• Chapman, Alice S., et al. "Diagnosis and management of tickborne rickettsial diseases: Rocky Mountain spotted fever, ehrlichioses, and anaplasmosis--United States: a practical guide for physicians and other health-care and public health professionals." MMWR. Recommendations and reports: Morbidity and mortality weekly report. Recommendations and reports/Centers for Disease Control 55.RR-4 (2006): 1. • Dantas-Torres, Filipe. "Rocky Mountain spotted fever." The Lancet infectious diseases 7.11 (2007): 724-732. • Shah, Usha, et al. "Trial of human diploid cell rabies vaccine in human volunteers." British medical journal 1.6016 (1976): 997-997. • Willoughby Jr, Rodney E., et al. "Survival after treatment of rabies with induction of coma." New England Journal of Medicine 352.24 (2005): 2508-2514. • Rupprecht, Charles E., and Robert V. Gibbons. "Prophylaxis against rabies." New England Journal of Medicine 351.25 (2004): 2626-2635.
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