8 November 2005
Ministry receives report on hospital discharge rates during painted apple moth eradication programme.
The Ministry of Health has received a report on hospital discharge rates for respiratory illness before and during the
painted apple moth eradication programme in West Auckland.
The Ministry of Agriculture and Forestry aerially applied the insecticide Foray 48B over parts of West Auckland from
January 2002 to May 2004 to eradicate the exotic pest, the painted apple moth.
The report: Descriptive Study of Hospital Discharges for Respiratory Diseases in Spray Zone for Painted Apple Moth
(Auckland) relative to local and national statistics 1999-2004 was written by the Institute of Environmental Science and
Research Limited (ESR). It was commissioned by the Ministry of Health inFebruary 2004 in response to concerns in the
community about respiratory illness.
The Health Impact Assessment, written prior to the eradication programme commencing, identified that some people may
have minor skin, eye and upper respiratory tract irritation, or aggravation of existing asthma or allergies if directly
exposed to the spray.
Aer’Aqua Medical Services, funded by the Ministry of Agriculture and Forestry, which provided health support service
during the programme, found that approximately 1.6% of the population in the residential area included in the
eradication programme reported health concerns. Most commonly reported symptoms were respiratory or skin ailments and
In its report, ESR found that there was no difference in the before-spray and during-spray monthly discharge rates for
influenza and pneumonia.
ESR found there was an increase in asthma discharge rates in the period 2002 to mid 2004 for boys aged 0-4 years old in
the exposed population. There was a small increase observed for girls aged 0-4 and 5-14 years old.
However ESR concluded that the underlying trend in hospital discharges for respiratory disease and asthma in the spray
zone was evident before spraying began and cannot therefore be attributed to this exposure.
ESR stated that while there were several findings pointing to a real increase in asthma discharges that could plausibly
be associated with the spray programme, chance, bias and other confounding factors were possible explanations for the
result and the authors stressed that the results do not prove that the elevations seen for some age groups were caused
by exposure to the spray.
Chief advisor Public Health, Dr Ashley Bloomfield said he hoped the findings would be reassuring to the West Auckland
“Given the increases occurred prior to the spraying, and the increases were very small numbers, there is nothing to
suggest a significant adverse impact on the incidence of respiratory diseases for the West Auckland population. It is
pleasing to be able to report this to the community as we know some people have been concerned about the effects that
this eradication programme may have had on health.”
The report is the first community-based study of hospital discharge data in response to long-term aerial application of
a biological insecticide.
The Ministry of Health is expecting a number of further reports from MAF. Once these reports are available, the Ministry
will review all the information it has received in relation to health issues associated with the eradication programme
and recommend to the Ministry of Agriculture and Forestry (MAF) what, if any, further investigation or action is
The Ministry of Health is one of several agencies who have provided advice to MAF on this programme.