No abstract

Objectives: To investigate two outbreaks of dengue type 2 in north Queensland, one in the Torres Strait beginning in late 1996, the other in a Cairns suburb in early 1997. Design: Epidemiological investigation of all laboratory‐confirmed cases of dengue, entomological investigation of the local environment, and laboratory analysis of the isolated dengue viruses. Main outcome measures: Numbers of confirmed and of locally acquired cases; virus serotype; comparison of nucleotide sequences between viruses isolated from the two outbreaks; and Breteau Index (Bl = number of containers with larvae of the mosquito vector Aedes aegypti found per 100 houses investigated) on the affected islands and in the Cairns suburb. Results: There were 201 confirmed cases of dengue in the Torres Strait outbreak, which lasted nearly seven months, and seven confirmed cases in the Cairns outbreak, which lasted about nearly 11 weeks. Most (190) were confirmed as dengue type 2. Nucleotide sequencing of viruses isolated from the two outbreaks showed they were identical. Ae. aegypti breeding sites were very common on the five Torres Strait islands surveyed (Bis, 73‐219 ‐ high risk), but less so in the Cairns suburb (Bl, 23). The most common breeding sites were water storage reservoirs, particularly rainwater tanks, on the outer Torres Strait islands, discarded containers (such as plastic containers, buckets and tyres) on Thursday Island, and garden items (such as flowerpot bases and jars) in Cairns. Conclusions: The virus responsible for the Cairns outbreak was most probably introduced from the Torres Strait, whereas the virus responsible for the Torres Strait outbreak was imported from Papua New Guinea. Preventive strategies tailored to specific locations are needed to reduce breeding of Ae. aegypti in north Queensland, and the consequent risk of future outbreaks of dengue.

We report 3 cases of spotted fever group rickettsial infection (presumed Queensland tick typhus) in residents of northern Queensland, Australia, who had unusually severe clinical manifestations. Complications included renal failure, purpura fulminans, and severe pneumonia. Clinical illness caused by Rickettsia australis may not be as benign as previously described.

Scrub typhus, caused by Orientia tsutsugamushi , occurs throughout Southeast Asia. We descript ten cases that occurred in the Torres Strait islands of northern Australia during 2000 and 2001. Preceding heavy rain may have contributed to the outbreak. The successful use of azithromycin in two pediatric patients is also reported.