Western Australia is experiencing the highest level of whooping cough (pertussis) notifications since 1997, when more than 1200 cases were notified.
More than 400 cases (180 in Perth) have been notified to the end of August 2004, compared to 230 cases in 2003.
Most cases have been notified since May, but 80 cases were notified in August, signalling a significant upward trend.
There have been outbreaks of the disease in the Great Southern region (over 160 cases), particularly around Denmark and Albany.
Clusters of cases have also been identified recently in other towns and in two Perth schools.
The Department of Health has urged parents to make sure that their children are fully immunised against whooping cough.
In WA, about 90 per cent of infants over 6 months of age and 83 per cent of children over six years of age are fully immunised against whooping cough.
The current Australian Standard Vaccination Schedule provides free whooping cough vaccine for children at 2, 4 and 6 months of age, 4 years of age, and, from 2004, children in Year 7 primary school.
Also, a single booster dose of the whooping cough vaccine Boostrix is recommended for parents having a baby.
Irrespective of vaccination programs, pertussis epidemics tend to occur every 3 to 4 years due to waning immunity in adults and adolescents, and WA is overdue for a whooping cough outbreak.
Whooping cough is a highly infectious bacterial disease spread by respiratory droplets.
Most cases occur in adolescents and adults but the disease is a major risk for infants, who can develop pneumonia or brain damage as a result of the infection.
Effective disease control relies on prompt diagnosis of cases, treatment with appropriate antibiotics and the exclusion of infectious cases from contact with vulnerable young children.