High-risk pests caught at New Zealand’s border

This section summarises the types of exotic mosquitoes and other insects which are caught at our border (international airports and seaports) by New Zealand’s mosquito surveillance programme. It tells us which exotic mosquitoes are arriving at our border, where they are coming from, and how they are getting here.

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An average of ten overseas exotic mosquito interceptions occurred each year, 2008-17

Twenty exotic mosquito species of public health concern intercepted, 2008-17

Most (64%) exotic mosquitoes travelled from the Asia-Pacific region, 2008-17

High-risk pests often travelled by sea and in general cargo

An average of ten overseas exotic mosquito interceptions each year, 2008-17

Between 2008 and 2017, there were 103 interceptions of exotic mosquitoes which were thought to have travelled to New Zealand from overseas (i.e. not local mosquitoes inadvertently caught) [1]. There were also 56 interceptions of non-mosquitoes (other insects) from overseas during this period. The majority of interceptions (>83%) took place in Auckland.

Twenty exotic mosquito species of public health concern intercepted, 2008-17

Twenty out of 37 types of exotic mosquito species caught at the New Zealand border, 2008-17, were of potential public health concern[1,2]. These included:

  • Eighteen interceptions of Aedes aegypti, the 'Yellow Fever mosquito'; a severe-risk species for many diseases e.g. Chikungunya, Zika, Dengue, and Yellow Fevers.
  • Seven interceptions of Aedes albopictus, the ‘Asian Tiger mosquito’; a severe-risk species for many diseases e.g. Chikungunya, Ross River and West Nile Virus.
  • Six interceptions of Anopheles species (with Malaria carrying potential).

Table 1 summarises all suspected mosquitoes of overseas origin caught at the New Zealand border, 2008-17 (See Table 1). 

Most exotic mosquitoes travelled from the Asia-Pacific, 2008-17

Most (64%) intercepted suspected mosquitoes originated from the Asia-Pacific region (Table 2) [1]. 

Australia was by far the biggest source.

Table 2: Number of suspected mosquito interceptions at the New Zealand border, by region and country of probable origin, and mode of travel, 2008-17

Region of Origin Country of Origin (Number of Exotic Mosquito and Exotic Non-Mosquito Interceptions) Percentage of Total Interceptions Mode of Travel

Asia

Bangladesh (1), Cambodia (1), China (2), Hong Kong (2), India (4), Japan (7), Korea (2) Malaysia (1), Philippines (3), Singapore (2), Taiwan (1), Thailand (3), Vietnam (1)
Total = 30

22.1

70.0% Sea, 
30.0% Air

 

Europe

Germany (2), Netherlands (1), UK (2)
Total = 5

3.7

100% Sea

Pacific

Australia (40), Fiji (6), New Caledonia (2), Niue (1), Papua New Guinea (1), Samoa (2), Tahiti (1), Tonga (1), Vanuatu (3)

Total = 57

41.9

73.7% Sea,  26.3% Air

The Americas

Argentina (1), Chile (1), Colombia (1), Ecuador (12), Panama (1), USA (8) 

Total = 24

17.6

87.5% Sea,  12.5% Air

 

Other

Unknown (20)

Total = 20

14.7

20.0% Sea,  75.0% Air, 

5.0% Unknown

Data source: New Zealand BioSecure, 2018.

High-risk pests often travelled by sea and in general cargo

The majority of high-risk pests travelled by sea, 2008-17 [1]. Over 99% of imported goods to New Zealand are transported by sea.

The most common places where suspected mosquitoes of probable overseas origin were found were:

  • 54% in ‘other cargo’ (e.g. household goods, motor vehicles, spas, shipping containers – recent contents not stated).
  • 17% in fruit shipments (e.g. bananas, mandarins)
  • 14% in tyre shipments (mosquitoes are attracted to tyres because they form a good habitat e.g. insulating properties, rainwater and vegetation can collect inside for larvae growth)
  • 12% in transit zones (e.g. international air terminals or dockside traps)
  • 5% in luggage (e.g. around passenger luggage or in baggage areas)
  • 1% in ‘other produce’ (e.g. flowers, wood, oats, corn) 

Table 3 shows the numbers of interceptions and types of locations where suspected mosquitoes, that thought to have travelled from overseas, were found at the New Zealand border, 2008-17.

Table 3: Table of annual suspected mosquito interceptions of probable overseas origin, by location discovered at the New Zealand border, 2008-17.  

Location 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total

Fruit

 2

17 

Luggage

0

 1

 0

 1

 0

Other cargo

 3

 6

 2

 3

 11

 11

 54

Other produce

 0

 0

 0

 0

 1

Transit zone

 0

 12

Tyres

 2

 3

 1

0

 1

14 

Total

 0

10 

 6

18 

13 

20 

18 

103 

Data source: New Zealand BioSecure, 2018

For information on indicator methodology, please see metadata sheet.

References

1. New Zealand BioSecure Entomology Laboratory. Mosquito interceptions dataset. Southern Monitoring Services Limited. (Accessed 2018 by personal correspondence)

2. New Zealand BioSecure Entomology Laboratory. Exotic Mosquitoes. Southern Monitoring Services Limited. (accessed May 2018). Available at: www.smsl.co.nz