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 nine overseas exotic mosquito interceptions occurred each year, 2006-15
Fifteen exotic mosquito species of public health concern intercepted, 2006-15
Most exotic mosquitoes travelled from the Asia-Pacific, 2006-15
High-risk pests often travelled by sea and in general cargo

An average of nine overseas exotic mosquito interceptions each year, 2006-15

Between 2006 and 2015, there were 86 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 63 interceptions of non-mosquitoes (other insects) from overseas during this period. The majority of interceptions (>80%) took place in Auckland.

Fifteen exotic mosquito species of public health concern intercepted, 2006-15

Fifteen out of 30 types of exotic mosquito species caught at the New Zealand border, 2006-15, were of potential public health concern[1,2]. These included:

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

Table 1 summarises all suspected mosquitoes of overseas origin caught at the New Zealand border, 2006-15 (See Table 1). 

Most exotic mosquitoes travelled from the Asia-Pacific, 2006-15

Most (73%) 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, 2006-15

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

Asia

Japan (6), China (6), Singapore (4),   Philippines (3), Thailand (3), India (2), Bangladesh (1), Cambodia (1), Hong Kong (1), Malaysia (1), South Korea (1), Taiwan (1), Vietnam (1)

Total = 31

25.4 %

29% Air, 71% Sea

Europe

UK (2), Germany (1), Netherlands (1)

Total = 4

3.3 %

100% Sea

Pacific

Australia (39), Fiji (6), Vanuatu (3), New Caledonia (2), Samoa (2), Cook Islands (2), American Samoa (1), Niue (1), Papua New Guinea (1), Tahiti (1)

Total = 58

47.5 %

26% Air, 74% Sea

The Americas

Ecuador (10), USA (4), Chile (2), Panama (1)

Total = 17

13.1 %

100% Sea

Other

Unknown (13)

Total = 13

10.7 %

38% Air, 62% Sea

Data source: New Zealand BioSecure, 2016.

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

The majority of high-risk pests travelled by sea, 2006-15 (Table 1) [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:

  • 48% in ‘other cargo’ (e.g. household goods, motor vehicles, spas, shipping containers – recent contents not stated).
  • 16% in fruit shipments (e.g. bananas, mandarins)
  • 11% in transit zones (e.g. international air terminals or dockside traps)
  • 10% 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)
  • 8% in luggage (e.g. around passenger luggage or in baggage areas)
  • 7% 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, 2006-15.

Table 3: Table of annual suspected mosquito interceptions of probable overseas origin, by location discovered at the New Zealand border, 2006-15.  

Location 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Total

Fruit

1

0

0

0

1

2

1

0

8

6

19

Luggage

0

1

1

0

0

0

1

1

3

3

10

Other cargo

7

9

5

8

6

6

2

6

5

4

58

Other produce

0

0

2

1

1

0

0

0

3

2

9

Transit zone

1

3

0

3

3

1

0

2

0

0

13

Tyres

2

0

0

0

2

4

1

0

2

1

12

Unknown

1

0

0

0

0

0

0

0

0

0

1

Total

12

13

8

12

13

13

5

9

21

16

122

Data source: New Zealand BioSecure, 2016

For information on indicator methodology, please see metadata sheet.

References

1. New Zealand BioSecure Entomology Laboratory. Mosquito interceptions dataset. Southern Monitoring Services Limited. (Accessed 2016 by personal correspondence with J Kasper, Senior Entomologist)

2. New Zealand BioSecure Entomology Laboratory. Exotic Mosquitoes. Southern Monitoring Services Limited. (accessed 8th June 2016). Available at: www.smsl.co.nz