Q Fever
• Query Fever
• Coxiellosis
Dr. Makram Sleiman DVM PhD
Overview
• Organism
• History
• Epidemiology
• Transmission
• Disease in Humans
• Disease in Animals
• Prevention and Control
• Actions to Take
ORGANISM
The Organism
• Coxiella burnetii
– Obligate intracellular pathogen
– Proteobacteria
– Stable and resistant
– Killed by pasteurization
– Two antigenic phases
• Phase 1: virulent
• Phase 2: less pathogenic
HISTORY
History
• 1935
– Queensland, Australia (abattoir worker)
– Montana, USA (ticks)
• Outbreaks
– Military troops
• When present in areas
with infected animals
– Cities and towns
• Downwind from farms
• By roads traveled by animals
TRANSMISSION
Transmission
• Aerosol
– Parturient fluids
• 109 bacteria released
per gram of placenta
– Urine, feces, milk
• Direct contact
• Fomites
• Ingestion
• Arthropods (ticks)
Transmission
• Person-to-person (rare)
– Transplacental (congenital)
– Blood transfusions
– Bone marrow transplants
– Intradermal inoculation
– Possibly sexually transmitted
EPIDEMIOLOGY
Epidemiology
• Worldwide
– Except New Zealand
• Reservoirs
– Domestic animals
• Sheep, cattle, goats, dogs, cats
– Birds
– Reptiles
– Wildlife
Epidemiology
• Occupational and
environmental hazard
– Farmers
– Livestock producers
– Veterinarians
and technicians
– Meat processors/
abattoir workers
– Laboratory workers
DISEASE IN HUMANS
Human Disease
• Incubation: 2 to 5 weeks
• One organism may cause disease
• Humans are dead-end hosts
• Disease
– Asymptomatic (50%)
– Acute
– Chronic
Acute Infection
• Flu-like, self limiting
• Atypical pneumonia (30 to 50%)
• Hepatitis
• Skin rash (10%)
• Other signs (< 1%)
– Myocarditis, meningoencephalitis,
pericarditis
• Death: 1 to 2%
Chronic Disease
• 1 to 5% of those infected
– Prior heart disease, pregnant women,
immunocompromised
• Endocarditis
• Other
– Granulomatous hepatitis
– Cirrhosis
– Osteomyelitis
• 50% relapse rate after antibiotic therapy
Risk to Pregnant Women
• Most asymptomatic
• Transplacental transmission
• Reported complications
– In-utero death
– Premature birth
– Low birth weight
– Placentitis
Prognosis
• Usually self-limiting
• Only 2% develop severe disease
• Active chronic disease
– Usually fatal if left untreated
– Fatality for endocarditis: 45 to 65%
– 50 to 60% need valve replacement
• Case-fatality rate: <1 to 2.4%
Diagnosis
• Serology (rise in titer)
– IFA, CF, ELISA, microagglutination
• DNA detection methods
– PCR
• Isolation of organism
– Risk to laboratory personnel
– Rarely done
Treatment
• Treatment
– Doxycycline
– Chronic disease – long course
• 2 to 3 years of medication
• Immunity
– Long lasting (possibly lifelong)
ANIMALS AND
Q FEVER
Animal Disease
• Sheep, cattle, goats
– May be asymptomatic
– Reproductive failure
• Abortions
• Stillbirths
• Retained placenta
• Infertility
• Weak newborns
• Low birth weights
– Carrier state
Animal Disease
• Other animal species
– Dogs, cats, horses, pigs
– Most other mammals
– Fowl species
• Often asymptomatic
• Reproductive failure may occur
Post Mortem Lesions
• Placentitis
– Leathery and thickened
– Purulent exudate
• Edges of cotyledons
• Intercotyledonary areas
• Aborted fetus
– Non-specific
Diagnosis and Treatment
• Diagnosis
– Identification of organism
– PCR
– Serologic tests: IFA, ELISA, CF
– Isolation of organism
• Hazardous - Biosafety level 3
• Treatment
– Tetracycline prior to parturition
Morbidity and Mortality
• Prevalence unknown
• Endemic areas
– 18 to 55% of sheep with antibodies
– 82% of dairy cattle
• Morbidity in sheep: 5 to 50%
• Death is rare
PREVENTION AND
CONTROL
Prevention and Control
• Good husbandry
– Tick prevention
– Disposal of birth products
• Separate new or sick animals
• Vaccination
– Human and animal
– Not available in U.S.
Prevention and Control
• Pasteurization
• Disinfection
– 10% bleach
• Eradication not practical
– Too many reservoirs
– Constant exposure
– Stability of agent in environment
Q Fever as a Biological Weapon
• Accessibility
• Low infectious dose
• Stable in the environment
• Aerosol transmission
• WHO estimate
– 5 kg agent released on 5 million persons
• 125,000 ill - 150 deaths
• Could travel downwind for over 20 km
Questions ?
