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Epidemiology of Q Fever Among U.S. Military Personnel During Operation Iraqi Freedom (OIF)

Epidemiology of Q Fever Among U.S. Military Personnel During Operation Iraqi Freedom (OIF) . Stephanie L. Scoville, DrPH. Introduction. Zoonotic disease caused by Coxiella burnetii Endemic in nearly every country Livestock are the major reservoir Primarily an occupational hazard

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Epidemiology of Q Fever Among U.S. Military Personnel During Operation Iraqi Freedom (OIF)

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  1. Epidemiology of Q Fever Among U.S. Military Personnel During Operation Iraqi Freedom (OIF) Stephanie L. Scoville, DrPH

  2. Introduction • Zoonotic disease caused by Coxiella burnetii • Endemic in nearly every country • Livestock are the major reservoir • Primarily an occupational hazard • Licensed vaccine not available in the U.S. • Notifiable disease in U.S. as of 1999

  3. Historical Background • 1935: First outbreak of Q (for query) fever among slaughterhouse workers in Queensland • 1935: Organism isolated from ticks collected along Nine Mile Creek in Montana • 1938: Connection between the groups made when a lab-acquired Q fever infection occurred in Montana • Organism named in honor of Harold Cox and Macfarlane Burnet 3

  4. Bacteriology • Obligate intracellular, gram-negative bacterium • Replicates in phagolysosome • Sporelike form can persist in the environment 4

  5. Modes of Transmission • Inhalation of aerosolized bacteria excreted by infected animals • Primarily domesticated ruminants (cattle, goats, and sheep) • Also associated with camelids, cats, and wildlife • Ingestion (raw milk) possible route • Tick bites unlikely 5

  6. Acute Illness • Flu-like illness, pneumonia, or hepatitis are most common • Asymptomatic infections may occur • Atypical manifestations possible • Infection may persist in an asymptomatic state 6

  7. Chronic Q Fever • Appears to be uncommon and may not develop until years after initial infection • Endocarditis is the most common manifestation • Higher risk for immunocompromised patients and those with pre-existing cardiac valvulopathy 7

  8. Chronic Q Fever • Diagnosis is usually serologic and not standardized • Treatment requires ≥ 18 months of doxycycline plus hydroxychloroquine • Unite' des Rickettsies researchers* proposed follow-up strategy in 2007 to obtain early diagnosis of chronic infection *Landais C, Fenollar F, Thuny F, Raoult D. From acute Q fever to endocarditis: serological follow-up strategy. Clin Infect Dis. 2007 May 15;44 (10):1337-1340. 8

  9. Strategy for diagnosing Q fever Reference: Hartzell J. D. et.al. Mayo Clin Proc. 2008;83:574-579 © 2008 Mayo Foundation for Medical Education and Research

  10. Military Significance • Outbreaks occurred among British and American troops during World War II • Only three cases diagnosed among U.S. military personnel during the Persian Gulf War • First recognized among U.S. military personnel during OIF during pneumonia investigation in summer 2003 • Potential biological warfare threat

  11. Possible Exposures During OIF • Foot patrols • Search operations • Helicopter operations • Explosive attacks • Controlled detonations of weapons caches • Recovery operations after explosions • Sleeping in stables, wool factories, or local homes

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  14. Note: Data from the following three slides were copied from a presentation prepared for the Force Health Protection Conference, August 2004 Q Fever in OIF-Deployed Soldiers: An Emerging Disease of Military Importance Alicia D. Anderson, DVM, MPH Major, Veterinary Corps, U.S. Army

  15. Severe Pneumonitis EPICON • 3/19 seropositive for Q fever by IFA 15

  16. Follow-up Q Fever Serosurvey • Serosurvey of 22 service members diagnosed with non-severe pneumonia while deployed • Pre- and post-deployment stored sera used to determine seroconversion • 5/22 seroconverted while deployed 16

  17. Serosurvey Results • Summary: 8/41 (19%) with pneumonia tested for Q fever were seropositive Pre-deployment antibody titers negative 17

  18. Note: Data from the following four slides were modified from a presentation prepared for an informal meeting at NNMC Bethesda, February 2008 Seroepidemiologic Survey of Q Fever Among U.S. Military Personnel During OIF MAJ Troy Baker, MD, MPH Walter Reed Army Institute of Research Division of Preventive Medicine

  19. Objective • Determine the burden of undiagnosed Q fever among U.S. military personnel deployed in support of OIF 19

  20. Methods • Created list of ICD-9 codes consistent with Q fever symptoms • Identified 970 potential cases that had been hospitalized in Iraq from 2003 through 2004 through PASBA • Sent 920 de-identified pre- and post-deployment serum specimens to WRAIR from the DoDSR 20

  21. Laboratory Testing • Specimens re-aliquoted at WRAIR and shipped to USAFSAM for IFA testing • Post-deployment specimens considered “potentially positive” if IFA titer ≥1:16 • Pre-deployment specimens were subsequently tested • Positive seroconversion required at least a 4-fold elevation in titers 21

  22. Top 3 Diagnoses with Seroconversion *organism not specified 22

  23. OIF Q Fever References • Anderson AD, Smoak B, Shuping E, et al. Q fever and the US military. Emerg Infect Dis. 2005;11:1320-1322. • Leung-Shea C, Danaher PJ. Q fever in members of the United States armed forces returning from Iraq. Clin Infect Dis. 2006;43:e77-82. • Faix D, Harrison D, Riddle M, et al. Outbreak of Q Fever among US Military in Western Iraq, June - July 2005. Clinical Infectious Diseases. 2008;46:e65-e68. • Gleeson TD, Decker CF, Johnson MD, et al. Q fever in US military returning from Iraq. Am J Med. 2007;120:e11-12. • Hartzell JD, Peng SW, Morris-Wood RN, et al. Atypical Q fever in US soldiers. Emerg Infect Dis. 2007;13:1247-1249. 23

  24. OIF Q Fever Published Cases (n=25) • 8 Soldiers from Mar-Aug 03 • 1 Soldier in Sep 03 & 1 Airman in Sep 04 • 9 Marines from Jun-Jul 05 • 2 Marines in Nov 04 & 1 Marine in Sep 06 • 1 Soldier in Jul 06 & 2 Soldiers in Dec 06 24

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  26. Department of Defense Reference Laboratory • U.S. Air Force School of Aerospace Medicine (USAFSAM) Epidemiology Lab Service at Brooks City-Base, TX • Indirect immunofluorescence antibody (IFA) test is the only FDA-approved test • IgG and IgM assay (Focus Diagnostics) 26

  27. DoD Research Assays • Research Assays • Enzyme-linked immunosorbent assays used by USAMRIID and NAMRU-3 • Polymerase chain reaction (PCR) tests using whole blood by USAMRIID • Joint Biological Agent Identification and Diagnostic System (JBAIDS) PCR awaiting FDA clearance 27

  28. Diagnostic Challenges for Deployed Providers • Significant time-lag for results (≥1 month) • CSH to LRMC to USAFSAM • Balad to WHMC to USAFSAM as of Feb 08 • Usually requires acute and convalescent specimen due to timing of seroconversion 28

  29. Clinical Practice Guidelines • Developed by the AFIDS Q Fever Working Group, April 08 • Acute disease treated with 21 days of 100 mg doxycycline, twice daily • Follow-up serologic testing for at least two years • Baseline transthoracic echocardiography (TTE) for all cases upon redeployment 29

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  31. Q Fever Surveillance During OIF • Initiated by USACHPPM Feb 07 • Monitor patient encounters using the Theater Medical Data Store • Collaborate with providers • Receive weekly lab reports from USAFSAM (as of Jun 2008) • Maintain a Q Fever Registry 31

  32. Surveillance Case Definition • Clinical evidence of acute illness: • Acute fever • One or more of the following: fatigue, chills, headache, acute hepatitis, pneumonia, or elevated liver enzyme levels • Serologic evidence of recent or active infection: • 4-fold antibody endpoint titer increase, or • Phase II IgM titer ≥ 1:128,* or • Phase II IgG titer ≥ 1:256* *If only a single sample was obtained 32

  33. USACHPPM Epidemiologic Questionnaire • Self-administered • Emailed to patients when operationally feasible • Assesses risk factors: • Demographics • Sleeping quarters • Modes of transportation • Local foods/beverages • Animals/insects • Tobacco use 33

  34. OIF Q Fever Epidemiology: U.S. Military Personnel • 90 cases Jan 07-Jun 08 • All male • 80 Army, 5 Marine Corps, 4 Air Force, 1 Navy • Median age: 29 years (range: 19-47) • Rank: 41 NCOs, 35 Junior Enlisted, 14 Officers • 53 cases with symptom onset in 2007 (average annual incidence of 3.4/10,000) 34

  35. Risk Factors • Various occupational specialties to include administrative, aviation, infantry, and medical personnel • Transmission primarily via inhalation • No temporal or geographic clustering 35

  36. Q Fever Cases by Month and Service, Jul 07-Jun 08* (n=66) 36

  37. Additional Cases • U.S. civilian and contractor employees in Iraq (n=8) • U.S. military personnel deployed to other locations • Afghanistan (n=2) • Ethiopia (n=1) 37

  38. Summary Q fever is a risk for travelers to Southwest Asia Empiric doxycycline for suspected acute Q fever Serodiagnostic testing (IFA) of acute and convalescent samples Reportable disease Chronic Q fever is rare but possible Serologic follow-up for at least two years and baseline TTE 38

  39. Contact info: stephanie.scoville@us.army.mil 301-319-9684 DSN 285-9684

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