Photo Credit USDA
# 6742
Yesterday, in Hong Kong: Investigating An Unidentified Respiratory Illness Outbreak, we learned of five workers at an animal management center in Sheung Shui who had contracted an as-yet unidentified respiratory infection.
Psittacosis (parrot fever) was suspected because they had been in direct contact with 16 seized parrots, three of which had subsequently died.
Today we get word that three patients have now tested positive for Chlamydophila psittaci, a bacteria shed in the feces of infected Psittaciformes (cockatoos, parrots, parakeets, lories, etc.) and poultry (ducks & turkeys primarily, less often in chickens) that can cause serious pneumonia in humans.
Human-to-human transmission, while rare, has been strongly suspected in the past (more on this after the HPC announcement below).
First, the statement from the Hong Kong Centre for Health Protection, then I’ll return with a bit more.
Update on psittacosis outbreak in Sheung Shui
The Centre for Health Protection (CHP) of the Department of Health today (November 27) provided an update on its joint investigation with the Agriculture, Fisheries and Conservation Department (AFCD) into an outbreak of psittacosis respiratory disease involving five AFCD male staff working in the New Territories North Animal Management Centre (NTNAMC) in Sheung Shui.
A CHP spokesman said that the respiratory specimens from three patients (a 55-year-old patient at Queen Mary Hospital, a 62-year-old patient in Alice Ho Miu Ling Nethersole Hospital and a 27-year-old patient who has been discharged from Yan Chai Hospital) tested positive for Chlamydophila psittaci by polymerase chain reaction as confirmed by the CHP's Public Health Laboratory Centre, suggesting that they were suffering from psittacosis infection.
So far, a total of five AFCD staff working in the NTNAMC have developed respiratory symptoms (mostly pneumonia) requiring admission to hospitals. One has recovered and the other four are currently in hospitals in Hong Kong (three) and Australia (one).
The CHP has successfully contacted 59 AFCD staff working in the NTNAMC and eight of them are found to currently have upper respiratory symptoms. Arrangements will be made with the Hospital Authority for these eight persons to undergo medical assessment and laboratory investigation to rule out psittacosis.
The joint investigation is under way. The total number of laboratory confirmed cases so far in this outbreak is three.
The spokesman said that psittacosis is a disease caused by Chlamydophila psittaci. It is usually transmitted to humans by inhaling the agent from the dried droppings and secretions of infected birds. Pet birds such as parrots, cockatiels, parakeets, macaws and poultry (turkeys and ducks) are most frequently involved. Person-to-person transmissions are rare.
Common symptoms include fever, headache, rash, muscle pain, chills and dry cough. Pneumonia may occur in serious cases. Encephalitis, myocarditis and thrombophlebitis are occasional complications. The incubation period ranges from one to four weeks. Psittacosis can be effectively treated with antibiotics.
To prevent psittacosis, members of the public are advised to take heed of the following measures:
- Wear gloves and face masks when handling the droppings and secretions of birds;
- Wash both hands thoroughly after handling birds;
- Avoid close contacts with birds;
- Disinfect bird cages and surfaces contaminated by bird droppings and secretions; and
- Seek medical treatment if symptoms develop.
Ends/Tuesday, November 27, 2012
Issued at HKT 19:01
Last March, in How Parrot Fever Changed Public Health In America, I briefly mentioned an ongoing investigation into a suspected parrot fever outbreak in Tayside, Scotland.
Two months later, the journal Eurosurveillance carried the following Rapid Communications that looked at onset dates and exposures in that outbreak (involving four family members and a health-care worker), all of which suggested human-to-human transmission.
Psittacosis outbreak in Tayside, Scotland, December 2011 to February 2012
C C McGuigan , P G McIntyre, K Templeton
A Tayside outbreak of psittacosis December 2011–February 2012 involved three confirmed and one probable cases. Confirmed cases were indistinguishable by sequencing of polymerase chain reaction (PCR) products.
The epidemiological pattern suggested person-to-person spread as illness onset dates were consistent with the incubation period and no single common exposure could explain the infections. In particular the only common exposure for a healthcare worker case is overlap in place and time with the symptomatic index case.
While outbreaks are uncommon, the CDC reports roughly 50 cases are diagnosed each year in the United States. As it can be difficult to diagnose, the true incidence of this disease probably much higher.
Treatment is via antibiotics, primarily with tetracycline.
One of the concerns with this disease is the widespread and essentially unregulated use of antibiotics by bird owners in treating their flocks. Overuse of antibiotics can lead to the development of resistant bacteria.
In 2007, an EID Journal report Chlamydophila psittaci Transmission from Pet Birds to Humans looked at the use of antibiotics at 39 breeding bird breeding facilities in Belgium, and found that more that 40% had used antibiotics to treat sick birds in the previous 12 months. More than 10% routinely gave antibiotics to birds prophylactically.
Although a small study, their findings suggested that bird owners may be infected – and display only mild symptoms - more often than previously suspected.
That said, among a small survey of bird owners - roughly 25% had reported having had pneumonia after acquiring a Psittaciforme as a pet - a number far greater than would normally be seen in the general population.
Prior to the development of antibiotics in the middle of last century, the mortality rate from psittacosis pneumonia was on the order of 15% to 20%. Today, if properly diagnosed and treated, deaths are rare.
However, should antibiotic resistance develop in Chlamydophila psittaci due to overuse, we could see a return to the bad old days.
