Rickettsial diseases can be categorised into scrub typhus, urban typhus, epidemic typhus and other rickettsial diseases, which include spotted fever. Different types of rickettsial diseases are caused by different types of 'rickettsiae'. Scrub typhus and spotted fever are more commonly seen in Hong Kong. Urban typhus is occasionally reported, while epidemic typhus has not been reported locally in the past few decades.
Rickettsial diseases in general present with features similar to a bad cold with fever, chills, headache and muscle pains, as well as rash. Scrub typhus and spotted fever are characterised by a punch-out skin ulcer at the site of bite of an infected arthropod. Nearby lymph nodes are also swollen and painful. Rickettsial diseases can cause severe complications and can cause death in severe cases.
Mode of transmission
Rickettsial diseases are transmitted mainly via vectors. Different types of rickettsial diseases are transmitted by different types of vectors, such as mite, flea, louse and tick.
Scrub typhus (also known as tsutsugamushi disease)
Urban typhus (also known as endemic typhus or murine typhus)
The incubation period for scrub, urban, and epidemic typhus is commonly 10 – 12 days, while that of spotted fever is 6 – 10 days.
Treatments for most rickettsial illnesses are similar. The diseases should be treated by appropriate antibiotics with supportive care.
The vectors transmitting scrub typhus and spotted fever are mainly found in vegetated areas. Therefore, preventive measures should be taken when visiting rural areas to avoid bitten by these vectors.
Prepare for the visit:
During the visit:
After the visit:
If an attached tick is found on the body:
Control of vectors and the reservoir of the diseases are also useful preventive measures:
Besides, since lice can live on human body, maintaining good personal hygiene is effective to prevent the spread of epidemic typhus.
Pregnant women and children of 6 months or older can use DEET-containing insect repellent. For details about the use of insect repellents and the key points to be observed, please refer to 'Tips for using insect repellents'.