(WBBM) – Lake County Public Health officials are concerned about a sharp spike in whooping cough cases since September.

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Epidemiologist Victor Plotkin says Lake County has had 73 cases this year, behind last year’s 115 total, but almost all of this year’s cases have come since September.

He says whooping cough, also called pertussis, had been battled to a standstill with vaccines by early 2000. But he says Lake County cases jumped to 160 suddenly in 2004, he believes, in part due to waning protectiveness of vaccines and also because of increase detection and public awareness.

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Plotkin says the concern is mainly over danger to infants who haven’t developed immunity to the bacterial disease.

He says any cough lasting longer than a week, especially without any accompanying cold symptoms, should be seen by a doctor.

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And Plotkin says everyone up to age 64 should be immunized against whooping cough.