An Analysis of notifications of persons with communicable diseases through to April 2001 (Table 2, Figure 1) indicates that both arboviral and salmonella infections began their expected declines with the onset of cooler weather. The notable exception to this trend was the Hunter Area Health Service, which experienced an increase in Ross River virus infection notifications in April. Notifications of pertussis also declined markedly to baseline levels from the three-year peak in mid-2000. Conversely, notifications of gonorrhoea have remained high among men in South Eastern Sydney.