Health agency sounds warning over rise in cryptosporidium cases

A computer illustration of cryptosporidium parvum parasites, the cause of cryptosporidiosis. Despite no major outbreak, Health NZ's National Clinical Director for Protection, Dr Susan Jack, says there has been a significant increase in cases of cryptosporidium this summer - especially in urban areas. Photo: KATERYNA KON / SCIENCE PHOTO LIBRA / KKO / Science Photo Library via AFP

A rise in cryptosporidium cases is prompting health warnings around the country, says Health New Zealand.

The parasite spreads through contaminated water and contact with infected people or animals.

A surge in cases during the summer has heightened public health concerns due to symptoms like diarrhoea, vomiting and stomach cramps.

Health NZ National Clinical Director for Protection, Dr Susan Jack, said 262 cases of crypto had been notified to public health services between the beginning of the year and 8 March.

That number was more than three times the average of 81 cases for the same time period over the last five years.

"These cases highlight the importance of people avoiding using swimming pools, splash pads, rivers, lakes and beaches for at least 14 days after they've had diarrhoea or other crypto symptoms - as well as keeping up with the other public health advice, including good hand hygiene to prevent spreading the bug to others.

"This means washing your hands with soap and water for at least 20 seconds and drying them thoroughly with a clean towel every time you go to the bathroom and before preparing food. Good hand hygiene is also important after contact with animals, after gardening, when caring for someone with diarrhoea, and when caring for a baby or changing nappies."

Jack said despite no major outbreak, there had been a significant increase in cases, especially in urban areas.

"There is currently no suggestion of a major cluster or concentrated outbreak, or any link to contaminated drinking water - which caused last year's Queenstown outbreak.

"But what we can say, is that in approximately half the cases where information is available, those who became unwell with symptoms had been involved in swimming-related activities - with the majority of cases overall happening in urban areas, particularly within the Auckland, Canterbury and Waikato regions."

A similar increase in crypto cases had also been reported recently by Queensland, New South Wales and Victorian health authorities, she said.

"The recent warmer weather and increased levels of swimming in recreational water have been identified as contributing factors.

"The National Public Health Service has increased disease surveillance across the motu to closely monitor crypto notifications and the spread of the disease."

Jack said crypto was a common cause of acute diarrhoea in children, so it was especially important they were kept home if they were unwell.

"To stop the infection spreading amongst tamariki, you should keep children home for at least 48 hours after having diarrhoea. Parents and carers should also wash their hands thoroughly after changing a child's nappies, and also wash the hands of the child."

Swimming areas could also be a cause of illness if they were contaminated by sewage or animal faeces, but there was no risk from public drinking water supplies, Jack said.

"To avoid getting crypto, people should check water quality monitoring warnings before jumping in the water.

"Land Air Water Aotearoa (LAWA) has information for the whole country, while those in the northern region can visit [www.safeswim.org.nz safeswim.co.nz] to check local water quality."

Anyone experiencing severe illness, difficulty maintaining adequate fluid intake or long-lasting diarrhoea should seek health advice.