Culex sitiens mosquito eradication

In March 2018, we found larvae from an exotic mosquito species, Culex sitiens, near the Kaipara Harbour, north of Auckland.

UPDATE – 5 JUNE 2020

Mosquito eradicated

Response manager David Yard: "It's now been 2 years since any have been found, and we're confident we can declare them eradicated."

Media release: Eradication of the mosquito Culex sitiens from New Zealand

Previous media releases

16 March 2018: More larvae found

13 March 2018: Surveillance programme finds exotic mosquito


A closeup of a Culex sitiens mosquito on a human hand
Culex sitiens mosquito

Culex sitiens is wide-spread in Southeast Asia, the South Pacific, and Australia.

It is known to transmit diseases such as Ross River virus. However, this is not a risk for New Zealand as this disease is not present here. Culex sitiens may also be able to transmit Japanese encephalitis but this has not been observed outside of a laboratory.

How was it found?

Culex sitiens larvae were found near the Kaipara Harbour in the Kawau Parua Inlet (north of Auckland). The larvae were found during regular surveillance as part of Biosecurity New Zealand’s National Saltmarsh Mosquito Surveillance Programme.

What was done?

Contractors for Biosecurity New Zealand took water samples and set light traps to collect larvae and trap adult mosquitoes in and around the area where the larvae were initially found.

Only a small number of larvae were found and no adults were detected. Surveillance of the surrounding area determined it did not spread from the site where they were originally detected.

On 13 November 2018, Biosecurity New Zealand began doing an aerial spraying programme to eradicate the Culex sitiens from the area near the Kawau Parua Inlet.

Biosecurity New Zealand had successfully eradicated exotic mosquitoes in the past, including from this area.

Who to contact

If you have any questions, email

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