Top End Souvenirs: Infectious Diseases. Dr Anna Ralph

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1 Top End Souvenirs: Infectious Diseases Dr Anna Ralph Infectious Diseases Staff Specialist, Royal Darwin Hospital Clinical Researcher, Menzies School of Health Research

2 Souvenir 1 Triage note says: 32 year old man presents with fever, anorexia and malaise after being out bush in the Top End NT for 6 weeks. CXR clear, LFTs abnormal, WCC 17, CRP 150 His bedside reading material is shown:

4 Which antibiotic would you prescribe? 1. Tazocin 2. Meropenem 3. Doxycycline 4. Moxifloxacin

5 What may he have? 1. Leptospirosis 2. Scrub typhus 3. Brucellosis 4. All of the above

6 Case details OT for? Necrotising fasciitis Myositis. No pus. No necrotising fasciitis Fasciotomy performed. Tissue for micro/culture. Vac dressing later required

7 Further information History: out bush for 6 weeks hunting pigs, fishing and wading in fresh, brackish and sea-water. Past history: gunshot wound to other leg hand injuries from prior hunting accidents Now, systemic illness with a constellation of: Myalgia / myositis Orchitis Hepatitis Cough Pharyngeal injection CRP Temperature

8 Leptospirosis thought to be most likely Treated with doxycycline and ceftriaxone, then doxycycline alone. Acute serology: Leptospiral serology Q fever serology Rickettsia serology Brucella abortus serology Melioid swabs Mumps serology Negative Negative Negative Negative Negative Equivocal

9 After a long hospitalisation (3 weeks) Lost 10kg. Extensive muscle wasting. Eventually recovered. Brucella abortus DAT Brucella abortus CFT Brucella IgG (EIA) Brucella IgM (EIA) Brucella sp. Tot Ab (agg Brucella sp. Tot Ab (CF) 23/07/ /07/ /08/ Negative Negative Non reactive Non reactive Non reactive Non reactive REACTIVE REACTIVE < <8 <8 <8 Probably Brucella suis. B. abortus eradicated (cross-reactive serology)

10 Souvenir 2 Healthy 38 year old man in NT for a fishing holiday,

11 Souvenir 2 Presented to RDH with exquisitely painful swollen leg, fever, hypotension. Pancytopaenia, coagulopathy, acute renal failure.

13 What may he have? 1. Leptospirosis 2. Brucella 3. Group A streptococcus 4. Vibrio sp 5. Aeromonas

14 Management and outcome Management: urgent extensive debridement - foot to groin. IV doxycycline and meropenem 24 to 48 hourly debridements for 10 days, forefoot amputation Split skin grafting of the limb a month later Vibrio vulnificus isolated from blister fluid and tissue specimens. Previously unrecognised underlying risk factor - haemochromatosis

15 Community-acquired pneumonia in the NT Top End

16 Darwin (latitude 12.5 S) Population 127,000 NT Population 230,000

17 What is melioidosis? 1. A disease due to an agent of bioterrorism 2. A cause of urinary retention 3. The second or third commonest cause of severe pneumonia in the NT s Top End (depending on the weather) 4. All of the above

18 Melioidosis Infection with Burkholderia pseudomallei Environmental bacterium in soil and surface water in endemic areas Disease in infected humans and animals Strong association with rainfall and environmental damage (soil /water aerosolisation)

19 Pneumonia aetiology Top End NT 2008 RHD study: 365 patients with CAP 72.6% no causative organism found Remaining 27.4%: pneumococcus most common Of those bacteraemic (n=42) Pneumococcus - 36% Acinetobacter - 14% B.pseudomallei - 12% Rest of Australia

20 The Darwin Prospective Melioidosis Study (Bart Currie) 887 cases over 25 years 114 deaths (13%) Darwin

21 Melioidosis Clinical Presentations 85% acute illness, recent infection Incubation Period 1-21 days (median 9 days) 55% blood culture +ve 22% present with septic shock 75% of these pneumonia is primary site mortality 50-90% if septic shock 11% chronic illness, recent infection Sick for > 2 months 4% reactivation from latent focus: up to decades later NB: 7% of returned American servicemen who had been stationed in Vietnam in 1960s tested seropositive

22 Melioidosis risk factors and mode of acquisition Host risk factors Immunosuppression Diabetes Renal failure Cancer chemotherapy High-dose steroids or other immunosuppresive drugs Alcohol intoxication Environmental risk factors Heavy rainfall High winds Wet season disease (December-March) Modes of acquisition Inoculating injury (via skin) Aspiration of organism (primary pneumonia)

23 Number of Cases 23 years of the Darwin Prospective Melioidosis Study Cases by Year 1989/ / TC TC Les Les TC TC Thelma TC TC Ingrid Ingrid TC TC Monica TC TC Helen Helen TC Carlos Year

24 Pneumonia 55% Deep-seated abscesses

25 Skin 13% Cutaneous Melioidosis - Often immunocompetent individuals after inoculating injury (plant, soil, water pipe, outdoor sporting injury)

26 Melioidosis diagnosis and management Diagnosis Culture Serology can be done but treatment is not warranted on the basis of serology alone (somewhat analogous to latent TB infection) Treatment IV ceftazidime (high dose) or IV meropenem for 2 weeks Oral co-trimoxazole (high dose) for 3 months Localised skin lesions can be potentially cured with oral therapy alone

Community-acquired Acinetobacter baumannii A cause of severe pneumonia in central and northern Australia and Papua New Guinea Unheard of elsewhere (Acinetobacter only known as a cause of

27 Community-acquired Acinetobacter baumannii A cause of severe pneumonia in central and northern Australia and Papua New Guinea Unheard of elsewhere (Acinetobacter only known as a cause of hospital-acquired infections, especially in ICUs) Wet season Hazardous alcohol likely throat colonisation, aspiration Lobar pneumonia Mortality > 50% in 1990s All isolates sensitive to gentamicin, meropenem, ciprofloxacin Barnes D et al. Rev Infect Dis 1988;10: Anstey N et al. CID 1992;14:83-91 Anstey N et al. J Clin Microbiol 2002;40:685-6

Mortality strongly relates to appropriate initial antibiotics Australia 1981-1991 Taiwan 1993-1999 Singapore 2007-2008 Hong Kong 2000-2003

28 Mortality strongly relates to appropriate initial antibiotics Australia Taiwan Singapore Hong Kong Australia Number of patients Appropriate initial therapy 11 36% 64% 13 31% 62% 8 13% 63% 19 32% 64% % 11% Hospital Mortality

29 What is the most common notifiable infection in the NT? 1. Melioidosis 2. Streptococcus pneumoniae 3. Trichomoniasis 4. Methicillin-resistant Staphylococcus aureus

30 STI cumulative rates by state/territory Cases per population 800 Chlamydia, gonorrhoea, syphilis and HIV cumulative rates by state and territory Chlamydia 600 Gonorrhoea Syphilis 500 HIV Cumulative Treatable STIs are common (lack of access to health education, disease prevention, treatment) ACT NSW NT QLD SA TAS VIC WA Source: National centre in HIV Epidemiology and Clinical Research, annual report 2003; ABS population data

32 1 cm 28yo male; sick 2 weeks Headaches, fevers, lethargy, myalgia, dry cough, truncal rash Had been in thick bushland pig hunting

33 What is the provisional diagnosis? 1. Leptospirosis 2. Scrub typhus 3. Brucellosis 4. Melioidosis 5. Rheumatic fever

34 Scrub Typhus (Orientia tsutsugamushi) Endemic rodent Rattus tunneyi Larval mite Leptotrombidium deliense Diagnosis: serology. Treatment: doxycycline.

35 Culex annulirostris, the common Darwin biting mosquito, may transmit: 1. West Nile virus (Kunjin subtype) 2. Barmah Forest Virus 3. Murray Valley encephalitis 4. All of the above 5. Nothing (no mosquito-borne infections in NT)

36 NT Arboviruses Virus Main vector Syndrome Diagnosis Murray Valley encephalitis Culex annulirostris Encephalitis Serology or PCR on CSF Kunjin (West Nile, Kunjin subtype) Culex annulirostris Encephalitis or Fever, arthralgia, rash Serology Ross River virus Culex annulirostris Aedes vigilax Fever, arthralgia, rash Serology Barmah Forest virus Culex annulirostris Fever, arthralgia, rash Serology

37 Final quiz 28 year old Top End Aboriginal man presents with cough and weight loss on the background of a longstanding chronic disease.

39 What two pathologies might this CXR show? 1. MRSA pneumonia and ischaemic heart disease 2. Pulmonary tuberculosis and rheumatic heart disease 3. Melioidosis and rheumatic heart disease 4. Any of the above

40 What did you learn? Unique infection epidemiology in Australia s Northern Territory Wet-season pathogens: melioidosis most important; community Acinetobacter a novel NT pathogen Zoonoses / environmental pathogens and arboviruses occur but are uncommon You may pick up an interesting souvenir, but of far greater importance is the burden of infectious diseases in Aboriginal people

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