Transcript Chris Whiteside Q fever 23rd Oct staff conference

Q fever
Chris Whiteside, CCDC, North Wales
NPHS Staff Conference
23rd October 2008
Q fever
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What is it?
How do you catch it?
Symptoms
Case studies from North Wales
Summary
Queries and concerns
What is Q fever
• Infection caused by a bacterium called Coxiella
burnetii
• It is a zoonosis, i.e. can be transmitted from
animals to humans
• Called Q (Query) fever for many years, as the
cause was unknown
• Around 50 cases of Q fever reported each year
• Infection can cause a range of
illness from no symptoms to
severe disease
• May cause outbreaks of illness
Bacterium Coxiella burnetii
• Carried by a wide range of
animals: sheep, cattle, goats;
birds, bats; domestic animals;
rodents and ticks
• Can survive as a highly resistant
spore-like form in the environment
for many months or years
• Found in almost every country in the world
apart from New Zealand
Q fever in animals
• Usually asymptomatic
• Prevalence in UK herds and flocks unknown
• Can cause inflammation of the placenta and
abortions
• Not a common cause of abortion, but may cause
outbreaks
• No formal vaccine programmes for livestock
• Written advice for farmers is available (Defra
and HPA websites)
How to catch it - transmission to humans
• Infectious dose can be as low as one organism
• The most infectious materials are amniotic
fluid of sheep, goats, cattle and cats;
also their milk, blood, urine and faeces
• Transmission occurs through inhalation of
contaminated aerosols, or infectious dust
• Often transmitted through
– contaminated bedding or litter
– directly from placenta or amniotic fluid
– dried windborne material especially from burning
animal bedding
– via tick bites
• Human to human transmission very rare
Symptoms - Q fever in humans
• Incubation period usually 2-3 weeks (up to 40 days)
• Often asymptomatic
• Seroprevalence in country-dwellers has been shown to
be up to 27%
• Acute Q fever - self-limiting febrile illness, hepatitis or
community-acquired pneumonia
• Flu-like symptoms of varying degree, with myalgia, fever,
headaches, sweats, joint and muscle pains, weight loss,
dry cough, pneumonia, chest / abdo pain
• Chronic Q fever - endocarditis, hepatitis, infection of
vascular grafts or aneurysms, chronic chest infection
• Acute:chronic cases 100:1
Diagnosis and treatment
• Serological tests as soon as possible
during the acute illness, and again three
weeks from onset
• Usually no treatment required
• For more severe symptoms, doxycycline
200mg o.d. for 2 weeks
• Early treatment gives a better outcome
Prevention and control
• Farmers: good hygiene at lambing, effective composting
of waste, safe disposal of bedding materials, separation
of infected animals
• No formal vaccine programme for animals
• A vaccine (Q Vax) for humans is available to at-risk
groups in Australia
• Tick control
• Avoidance: people in high risk groups - pregnant women,
immunosuppressed, valvular heart disease, should stay
away from sheep giving birth, and avoid occupations
with risk of exposure
Case 1, aged 47
• Steve, aged 47, lives near Mold
Case 1
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Lives near Mold
Digital telephone engineer, works all over England and Wales
Past history
- vit B12 deficiency
- pleurisy x2 late 1980s and early 1990s
- high blood pressure since 2002
Tues 29th April 2008 developed flu-like symptoms, headache and
anorexia while away on a course
Wed 30th felt worse and drove home, feeling very weak, having to
stop and rest several times on the way back
Arrived home pouring sweat, also diarrhoea and vomiting
Rang NHSD who advised paracetamol
Thurs 1st May pm developed pains in back and went to A&E
Wrexham Maelor
Case 1
• Clinical examination at A&E: fever, expiratory wheeze, and enlarged
liver
• Investigations: normal CXR, ?abnormal ECG, blood tests +++
• Initial diagnosis: pericarditis, admitted under cardiologist
• Friday 2nd May – remained very poorly, looked awful, temp 39.6.
CXR – shadow R lung
• Diagnosis: atypical pneumonia? mycoplasma / legionella …..
• Rx iv antibiotics clarithromycin and cefotaxime
• Admitted to High Dependency Unit
• Mycoplasma/legionella – urine tests negative
• Sunday 4th May – antibiotics changed to levofloxacin, clarithromycin
and rifampicin
• Transferred to respiratory ward and improved over next few days
• Discharged once mobile
Case 1
• Back at home, still felt very weak, wobbly,
unable to lift heavy objects, slept a lot, thrush on
tongue, noticed his skin reacted to sunlight
• 27th June - follow up appt resp physician,
serology tests carried out
• 1st Aug - results rung through to HPT office from
CoCH lab
• Q fever antibodies positive
IgG > 1280
IgM > 1280
Phase 1 CFT < 16
Phase 2 CFT > 512
Case 1
13th Aug, interview carried out at home (CW)
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To give information on Q fever
Discussion of clinical progression of his disease
Exploration of possible sources of infection
Identification of other linked cases
Control measures if needed
• Steve lives in a rural area with his partner, two
dogs, chickens and two horses
Case 1
• Animal contacts :
– Sheep and lambs in surrounding fields
– Goats kept by neighbours
– 2 dogs, 2 horses, chickens at home
• Horses are fed hay, 200 bales per year
• He bought fresh hay on 18th April 2008, which
was kept in stables
• Old hay was kept in the ‘small room’ next to the
stable, and usually taken to the tip for disposal
Case 1
• Steve had been on holiday
during winter 2007,
and a neighbour had
(over-) fed the chickens
• Excess chicken feed strewn around
the property
• Rats came in and
nested in the old hay
Case 1
• The old hay was not useable as
horse fodder, and so he decided
to give it to the neighbours to
build a goat house
• 12th May: lifted and transferred
the hay bales in his trailer
• Onset of illness 29th May fits with
incubation period (17 days)
Case 2, aged 32
• Computer technician, works in peoples homes in
Anglesey and Conwy
• Lived in Anglesey for 8 years
• Partner aged 29, and was 20 weeks pregnant
• 16th April 2008 he became ill with headache
• Next few days became worse with malaise,
aching legs, feverish, dry cough and sob,
anorexia, muscle and joint pains
• 20th April increasing weakness and noticed he
had brown urine
Case 2
• 999 call, admitted to hospital
• Diagnosed with rhabdomyolysis and
respiratory failure and admitted to ITU
• Intubated and ventilated for 8 days
• On haemofiltration for several weeks
• Q fever serology positive, notified to HPT
on 16th May
• Interviewed on renal ward 20th May
Case 2 - possible sources of
infection
• Pets: a cat and a bull terrier
• 30 sheep kept in field 10
metres from house, where
they lambed in early April
He walked past one sheep
in labour
• Fits in with incubation period
for onset of disease (16th April)
Case 3, aged 59
• Lives near Wrexham, works as a hospital
maintenance electrician
• 24th June: sudden onset of flu-like illness while
away on a course
• Symptoms – fever, sweats, cough, sob, chest
pains
• 3rd July: admitted to Wrexham Maelor
• Pneumonia diagnosed
• Discharged without a specific diagnosis
• Serology showed acute Q fever 1st August
Case 3 - possible
sources of
infection
Q fever summary
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Zoonosis
Highly resistant organism
Under-reported illness
Difficult to diagnose clinically
Often there are no symptoms
Source often not found
It is important to consider Q fever in cases of flulike illness or atypical pneumonia
• May cause severe illness, particularly in
vulnerable groups
Potential as a bioterrorism agent
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Easy to obtain
Present worldwide in farm animals
Potential agroterrorism agent – no clinical signs in animals
Environmental persistence > 1 year
Resistant to common disinfectants
Airborne dissemination
Easily inhaled by humans
Low infective dose
Naïve target population – no vaccine outside Australia
Not usually life-threatening, but potential for life-threatening
sequelae
– Major impact – Panic !
Queries
Source
What is the
prevalence in
these animals?
What are the
animal
reservoirs?
Why is it not
more
common?
How is it transmitted
to humans?
How is it spread in
the environment?
Pathway
Receptor
Why are some
people
unaffected?
Others are
seriously ill