The Hong Kong Centre for Health Protection (CHP) of the Department of Health is today (November 20) investigating a cluster of three cases of spotted fever affecting three men who hiked in Tai Lam Country Park from October 18 to 19, and hence appealed to members of the public to be vigilant against typhus and other rickettsial diseases.
The first patient is a 15-year-old man with good past health. He presented with fever, rash and skin ulcer over the right leg on October 26. He was admitted to Princess Margaret Hospital (PMH) on October 30. He has been in stable condition all along and was discharged on November 3.
The second patient is a 16-year-old man with good past health. He presented with fever and rash on November 2. He was admitted to a private hospital on November 6. He has been in stable condition all along and was discharged on November 14.
The third patient is a 43-year-old man with good past health. He presented with fever, rash and skin ulcer over the left knee on October 25. He was admitted to PMH on October 30. He has been in stable condition all along and was discharged on November 10.
Serology tests by the CHP’s Public Health Laboratory Services Branch confirmed that all three patients had spotted fever. Preliminary investigation revealed that the three patients hiked in Tai Lam Country Park with about 20 persons. The CHP is contacting them. Investigations are ongoing.
Spotted fever is transmitted by ticks, a vector which is usually found in scrubby areas or on rodents and stray animals that have been to scrubby areas. Most patients had history of outdoor activities in vegetated areas, for example, hiking in rural areas.
The clinical presentation of spotted fever is fever, chills, headache, muscle pains and body rash. Spotted fever is characterised by a primary punched out skin ulcer corresponding to the bite site of the arthropod. Lymph nodes near the skin ulcer may be swollen and painful. In extreme cases, this disease may cause severe complications and can be fatal.
The incubation period of the disease is commonly six to 10 days. People who suspect they have spotted fever should consult doctors. Antibiotics are effective treatment.
Typhus and other rickettsial diseases are statutory notifiable diseases in Hong Kong.