Influenza viruses are in the air around the Wanganui district although not in numbers seen a couple of years ago.
Dr Bill Douglas works for Quay Medical Centre in the city, one of two practices in the district supplying influenza data every week to Environmental Science and Research Ltd (ESR) in Wellington.
ESR is contracted to the Ministry of Health to maintain laboratory-based surveillance of notifiable diseases. The other Wanganui practice providing information is in Marton.
Dr Douglas said in the week ended August 12, the two practices had recorded 37 cases of flu.
"Four of them were Type A, 31 were the H3N2 virus (known as Perth flu) and one was H1N1 which is swine flu," he said.
He said at the moment, flu numbers in the Wanganui district appeared to have peaked at the levels reached in 2010.
"But in 2009 they were two to three times higher," he said.
Judith Bothma, patient safety and quality manager for the Wanganui District Health Board, said there had been patients reporting to Wanganui Hospital's front door with flu symptoms, not uncommon at this time of year.
"Anecdotally, there appears to be a slight decrease this week," Mrs Bothma said.
Dr Douglas said the current flu strains had arrived in Wanganui over the last three weeks.
"Prior to that, there were no confirmed cases of influenza here."
He said influenza was a viral illness that showed itself with sudden onset of fever, headache, coughs, sore throat and muscular aches and pains.
"In children and infants, their temperature goes up to 38.5 to 40C, often their eyes are reddened, they develop a cough and may be off their food and miserable. If older, they may complain of a headache and sore arms and legs.
"The first reported case of influenza in Wanganui was a seven-month-old."
He said surgeries were normally seeing adult patients four or five days after they had the virus when they felt up to "crawling out of bed".
But Dr Douglas said some of these people were showing up at Whanganui Accident and Medical clinic after hours because their employers were demanding a medical certificate.
"Legally these consultations don't attract a general medical subsidy payment and the cost advertised at the clinic is around $100.
"This should be reimbursed by the employer if they really want a certificate which says the employee reported to a doctor or nurse and states that they were unable to attend work for [several] days."