The rise and fall of Paterson’s Curse pollen

Paterson’s Curse (Echium plantagineum) is a significant invasive plant introduced to Australia from the Old World regions in the 1850s. Paterson's Curse has been a dominant broadleaf pasture weed through much of southern Australia and also infests native grasslands, heathlands and woodlands. It is wind and insect pollinated and produces large amounts of pollen during September to January, peaking in October and November. The pollen has been been linked to allergy risk for rural as well as urban populations.

Recent media coverage of research into the potential toxic impact of Paterson’s Curse pollen on the honey industry has generated comments about the declining amount of this pollen type being present in the environment due to biological control agents introduced in the last few years.

The graph below depicts the cumulative amount of pollen in Canberra’s atmosphere for each season from 2007 to 2015 and shows that Paterson’s Curse pollen abundance has been steadily declining over the last decade. In 2015 we recorded NO Paterson’s Curse pollen in the Spring to Summer count. This may represent a temporary or longer-term collapse of the Paterson’s Curse weed population in the ACT and region. Either way its good news for allergy sufferers and honey producers/consumers alike.

 

Figure shows the cumulative Echium plantagineum pollen load for Canberra illustrated for individual years since recording began in 2007 (Oct-Dec recording period). Echium pollen was found to be absent in 2015.

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Real Estate agents and 18-25 year olds hit hardest by hay fever in the ACT

The pollen monitoring season may came to a end on the 31st December 2015 but since then I have been sifting through the data and begin to discover new insights into how pollen impacts on different parts of the population in our region. In 2015 the CanberraPollen project introduced an extended survey option to the mobile app that included questions about participants work area, age and gender. The results are now in and there are some interesting patterns in the data that we report here. Overall the response to our survey has been excellent with around 4000 people filling in the new survey questions out of a total of 11000 people who have downloaded the app. This represents a significant portion of the ACT population (>1% engage with the survey) with the app downloads and information reaching around 3% of the total population.

What did the survey tell us? The graphs below show the average symptom score response derived from the 4000 participants (ranging from 1-5 with 1= none and 5= severe) in three selected areas of interest: Occupation, Gender and Age. They also show the % of participants using some form of medical intervention to treat their hay fever symptoms during the season.

These results can be summarized as follows for gender and age (Figure 1):

  1. Female and male participants show only a slight difference in average symptom scores with females reporting slightly more severe symptoms on average compared to males (consistent with AIHW Report in 2011).
  2. A similar % of female and male participants report using some form of medical intervention to treat their hay fever symptoms during the season (63-65%).
  3. There is a declining trend in symptom scores from younger to older participants. The younger participants are less likely to use hay fever treatments than the older cohorts, with the exception of the 61+ age category who report using the least amount of medical intervention of all despite having low symptom scores.

Figure 1: Gender and Age versus Average Daily Symptom Score (including standard error). The percentage of participants using some form of medical intervention to treat their hay fever symptoms during the season appears above each histogram.

The results for the Occupation category can be summarized as follows (Figure 2):

  1. 26 different occupation categories had >10 participants (total of 3830 respondents) in this survey and they are listed from lowest average symptom score to most severe symptom score in Figure 2.
  2. Participants in occupations that report the most severe symptoms throughout the season include those working in Real Estate, Hospitality, Community Services, Advertising and Architecture. Many of these occupations require the employee to travel to a variety of work sites rather than spend lots of time in the same office, which may expose them to a greater variety of pollen types during the season.
  3. Participants in occupations that report low symptom scores throughout the season include those working in Mining, Engineering, Retail, Trades and Management. Some of these occupations require the employee to work outdoors, however, this would include construction/mining sites where vegetation is sparse or where work is conducted in office environments.

Figure 2: Occupation versus Average Daily Symptom Score (including standard error).

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Farewell from the pollen count for 2015

Thanks for your support and interest in our work.  The Canberra Pollen Count is over for 2015 but we will be back bigger and better than ever in Spring 2016.

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Canberra Pollen Count results are in for 2015

Earlier in the season I predicted that this season would be a “Godzilla” hay fever season, and while this was true for the early part of the season a period of unusually high rainfall for early November led to much lower counts than expected for the peak November period. In the severe season of 2014 just under 2500 grass pollen grains were caught in our trap over the October-December recording period. Over the same period in 2015 the total was 2150, which is an average of just over 23 grass pollen grains per day, a number that sits within our moderate range. We only had 9 days that were HIGH or SEVERE pollen days compared to 30 in 2014, though if the heavy rains of early November had not occurred then this number would have been much higher.

Figure 1. Top graph shows the cumulative pollen load for Canberra illustrated as the minimum, average and maximum for years since recording began in 2007 (Oct-Dec recording period). The pollen load for 2015 up until the end of December is depicted in red. The bottom graph shows the long term average and standard deviation for an entire year based on historic records of grass pollen in Canberra. High rainfall period (total = 64mm) recorded in first 2 weeks of November 2015.

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Learn more about pollen - Paterson's Curse

Paterson’s Curse (Species, Echium plantagineum; Family, Boraginaceae)

Paterson’s Curse (Echium plantagineum) is a winter annual plant originating in Europe, northern Africa, and southwestern Asia. In the 1850s it was introduced to Australia, probably both as an accidental contaminate of pasture seed and as an ornamental plant. Paterson's Curse is now a dominant broadleaf pasture weed through much of southern Australia and also infests native grasslands, heathlands and woodlands. It is wind and insect pollinated and produces large amounts of pollen during September to January.

A high proportion of people with respiratory allergies test positive to Paterson’s Curse pollen in Australia making it a significant allergy risk for rural as well as urban populations. 

 

Distribution of Paterson's Curse (Atlas of Living Australia occurrence map)

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