Groote Eylandt exotic mosquito survey report 30 January to 2 February 2017

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Department of Health is a Smoke Free Workplace

Groote Eylandt exotic mosquito survey report 30 January to 2 February 2017

Megan Hoskins and William Pettit

Medical Entomology

Centre for Disease Control

Department of Health

Northern Territory Government

April 2017

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Medical Entomology, Centre for Disease Control

 Department of Health, Northern Territory 2017

This publication is copyright. The information in this report may be freely copied and distributed for

• non-profit purposes such as study, research, health service management and public information subject to the inclusion of an acknowledgment of the source. Reproduction for other purposes requires the written permission of the Chief Executive of the Department of Health, Northern Territory.

An electronic version is available at: http://digitallibrary.health.nt.gov.au/prodjspui/

General enquiries about this publication should be directed to:

Nina Kurucz Director

Medical Entomology CDC Department of Health 7PO Box 41326, NT 0811 Phone:

(08) 8922 8901 Facsimile:

(08) 8922 8820

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DEPARTMENT OF HEALTH

Page 2 Department of Health is a Smoke Free Workplace

Background

Alyangula is a mining town, located on Groote Eylandt, with approximately 400 properties.

The town supports about 1400 residents who are mainly Groote Eylandt Mining Corporation (GEMCO) employees or employees of support services.

Routine adult mosquito monitoring, using CO₂baited EVS traps, has been conducted by GEMCO in Alyangula since July 1981. The program was suspended in October 1983 but resumed in February 1995, with fortnightly adult mosquito trapping carried out by GEMCO until January 2014. Following another program suspension, the program fully resumed in January 2016. Limited trapping was carried out by Medical Entomology (ME) of the Department of Health (DoH) during an exotic vector survey in April 2015.

Routine ovitrap surveillance has been conducted in Alyangula since July 1998, with a program break of three years between 2000 and 2003. The ovitrap program detected the Aedes aegypti (dengue mosquito) incursion on Groote Eylandt when an ovitrap at the wharf was found to contain larvae of this exotic species 20 October 2006. The subsequent elimination program, managed by ME, found Ae. aegypti breeding on 93 properties in Alyangula and on one property in Angurugu. The program was successful in eliminating Ae.

aegypti from Groote Eylandt and concluded in April 2008. The ovitrap program was suspended again in March 2014 but fully resumed in February 2016.

To ensure Groote Eylandt remains free of the dengue vector, ME visited Groote Eylandt between 30 January and 2 February 2017 to carry out an exotic mosquito survey.

Operations included larval mosquito surveys at various properties in Alyangula, as well as setting of CO2 baited BG (BioGents) sentinel adult mosquito traps in the town, and conducting a mosquito larval survey at the Angurugu sewage ponds. This report outlines the activities and results from this survey.

Alyangula mosquito larval survey

The yards of 29 properties were entered and surveyed for mosquito larvae between 30/01/17 and 2/02/17 (Figs 1 & 3). Of these, 20 properties were classed as residential and the remaining nine either as commercial or transport properties. Twenty six properties were positive for mosquito larvae, with a total of 883 receptacles found to be holding water. Of these, 37 (4%) were colonised with mosquito larvae (Table 1). Examples of items breeding mosquitoes are shown in Figs 4, 6 & 8.

A total of six mosquito species were found during the survey, including Aedes notoscriptus Ae. katherinensis and Ae. tremulus (Table 1). These species lay desiccation resistant eggs and select breeding sites in a similar way to the exotic mosquitoes Ae. aegypti and Ae.

albopictus (Asian tiger mosquito).

Alyangula adult mosquito trapping

CO₂ baited BG sentinel traps were set in five locations in the residential area of Alyangula during the visit (Figs 2 & 5) and were left to run for 24 hours. The most common mosquito species collected in all the traps was Ae. katherinensis. The overall number of mosquitoes

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captured in each trap was low, and no exotic species were collected in any of the traps (Table 2).

Angurugu sewage ponds – site visit

The Angurugu sewage ponds were surveyed on 30/01/17. Recommendations with respect to minimising mosquito breeding in the ponds and in any environmental releases from the ponds have been communicated to PowerWater.

Other activities

During the ME visit, access to the GEMCO tyre storage compound was granted (Fig. 7). All the tyres stored at this site were holding water. Seventeen tyres were sampled, with two tractor tyres found to be breeding mosquitoes (Table 1).

The survey in the Alyangula wharf area found plastic bollard barriers positive for mosquito breeding (Table 1, Fig. 8). This is of great concern, as the barriers could become an Ae.

aegypti breeding site, if this species was introduced. The barriers need to be rectified to ensure they are not holding water or be treated with insecticides on a regular basis. To ensure no water enters the barriers, biosecurity stickers can be applied (Fig. 9).

Conclusions

The high number of receptacles holding water and being colonised by mosquitoes indicates that Alyangula remains vulnerable to widespread establishment of the exotic mosquito species Ae. aegypti and Ae. albopictus. The most likely point of entry will be the Alyangula wharf through international shipping or drought resistance eggs from northern Queensland.

The close proximity of Alyangula’s residential areas to the wharf makes the town vulnerable to exotic mosquito introductions.

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TABLE 1: Alyangula exotic mosquito survey 30 January to 2 February 2017 - Summary of receptacle description and mosquito species collected.

NUMBER O F C O NTAINERS PO SITIVE FO R EAC H SPEC IES

ADDRESS C O NTAINER DESC RIPTIO N Total No. of potential containers Total No. of containers inspected Total No. of containers with water Total No. of containers breeding % of containers with water breeding Ae. (Fin) notoscriptus Ae. (Mac) tremulus Ae. (Stg) katherinensis Ae. (Stg) species * Culicine pupae Cx. (Cux) quinquefasciatus Cx. (Cux) sitiens Lu. (Met) halifaxii

LS1 Connie Bush St Esky 1 1 1 1 100.0 1 0 1 0 0 1 0 0

LS2 Cypress St Pot plant (terracotta) 1 1 1 1 100.0 1 0 1 0 0 1 0 0

LS3 Brunker St Bowl (ceramic) 1 1 1 1 100.0 1 0 1 0 0 0 0 0

LS4 Bougainvillea Drive Tyre (car) 4 4 4 4 100.0 2 0 2 0 0 2 0 0

LS5 Muninga St Bucket (plastic) 1 1 1 1 100.0 1 0 1 0 0 0 0 0

LS6 Bara St Bucket (plastic) 1 1 1 1 100.0 1 0 0 0 0 0 0 0

Tyre (earthmoving equipment) 1 1 1 1 100.0 1 0 0 0 0 1 0 1

LS7 Carpentaria Crt Tyre (car) 1 1 1 1 100.0 1 0 0 0 0 1 0 0

LS8 Poinciana St Bucket (plastic) 1 1 1 1 100.0 0 0 0 0 0 1 0 0

LS9 4X Hill ATCO Container (equipment storage) 2 0 0 0 0.0 0 0 0 0 0 0 0 0

Sump (concrete) 1 1 1 0 0.0 0 0 0 0 0 0 0 0

LS10 Ngwunga St Tyre (tractor) 2 1 2 1 50.0 1 0 0 0 0 1 0 0

LS11 Ngwunga St Tyre (car) 1 1 1 1 100.0 1 0 0 0 0 0 0 0

LS12 Ngwunga St Tyre (car) 1 1 1 1 100.0 1 0 0 0 0 0 0 0

LS13 Smith St bromeliad 200 10 100 0 0.0 0 0 0 0 0 0 0 0

Pond 2 2 2 0 0.0 0 0 0 0 0 0 0 0

LS14 Shooting Range Tyre (car) 300 10 300 2 0.7 2 1 1 0 0 0 0 0

LS15 Shed Cypress Rd Tyre (car) 1 1 1 1 100.0 1 1 1 0 0 0 0 0

LS16 Cypress Rd Tray (plastic) 1 1 1 1 100.0 1 0 0 0 0 1 0 0

LS17 Ayawarra Cres Boat (dinghy) 1 1 1 1 100.0 1 0 0 0 1 1 0 0

LS18 Cypress Rd Tarpaulin 1 1 1 1 100.0 1 0 0 0 0 0 0 0

LS19 Dugong Beach Resort Bowl (stone) 2 2 2 0 0.0 0 0 0 0 0 0 0 0

Bucket (plastic) 2 2 0 0 0.0 0 0 0 0 0 0 0 0

Plastic container 25 5 15 1 6.7 1 0 1 0 0 0 0 0

Pond 1 1 1 0 0.0 0 0 0 0 0 0 0 0

LS20 Eylandt Automotive Tyre (car) 20 1 1 1 100.0 0 0 1 0 0 0 0 0

LS21 Cypress Rd Bin (metal) 1 1 1 1 100.0 0 0 0 0 1 1 0 1

Bucket (plastic) 3 1 3 1 33.3 1 0 0 0 1 1 0 0

Fridge (disused) 1 1 0 0 0.0 0 0 0 0 0 0 0 0

LS22 Stokes Cl Drum (200 L) 1 1 1 1 100.0 1 0 0 0 0 0 0 0

Pond 2 2 2 0 0.0 0 0 0 0 0 0 0 0

LS23 Stokes Cl Bucket (plastic) 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Pot (cooking) 1 1 1 1 100.0 0 0 1 0 0 0 0 0

LS24 GEBIE Development Trailer 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Tyre (earthmoving equipment) 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Tyre (truck) 15 2 15 2 13.3 1 2 1 1 0 2 0 0

LS25 TOLL yards and offices Bin (metal) 2 2 2 0 0.0 0 0 0 0 0 0 0 0

Boat 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Bollard 19 8 5 1 20.0 0 1 1 0 0 0 0 0

Machinery 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Tarpaulin 6 3 6 1 16.7 1 0 1 0 0 0 0 0

Tyre (car) 15 5 0 0 0.0 0 0 0 0 0 0 0 0

LS26 Health Offices Wheel barrow 1 1 1 1 100.0 1 0 0 0 0 1 0 0

LS27 GEMCO - Tyre yard Tyre (earthmoving equipment) 300 10 300 0 0.0 0 0 0 0 0 0 0 0

Tyre (tractor) 90 7 90 2 2.2 2 0 0 0 0 0 1 0

LS28 Nursery Alebuwa Street Box (plastic) 5 1 1 1 100.0 1 0 0 0 0 1 0 0

Bucket (plastic) 1 1 1 1 100.0 1 0 0 0 0 0 0 0

Styrofoam box 2 2 2 0 0.0 0 0 0 0 0 0 0 0

Tray (plastic) 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Trolley 1 1 1 1 100.0 1 0 0 0 0 0 0 0

LS29 Pole 13 Boat (dinghy) 1 1 1 0 0.0 0 0 0 0 0 0 0 0

Septic 2 2 2 0 0.0 0 0 0 0 0 0 0 0

TO TALS 1050 112 883 37 29 5 14 1 3 16 1 2

% O F TO TALS 10.67 84.10 3.52 78.38 13.51 37.84 2.70 8.11 43.24 2.70 5.41

% O F C O NTAINERS W ITH W ATER BREEDING 4.2

* Ae (Stg) species - pupa in sample most likely that of Ae. (Stg) k atherinensis.

PREMISES AND PO TENTIAL C O NTAINER SUMMARY

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TABLE 2: Alyangula exotic mosquito survey 30 January to 2 February 2017 - Summary of mosquito species collected in CO

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baited BG adult mosquito traps.

Ae. (Fin) kochi Ae. (Fin) notoscriptus Ae. (Mac) tremulus Ae. (Och) vigilax Ae. (Stg) katherinensis An. (Cel) amictus An. (Cel) annulipes s.l. Cx. (Cux) annulirostris Cx. (Cux) quinquefasciatus Cx. (Cux) sitiens Tp. (Trp) magnesianus

Trap location Trap type Date set Date collected No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males No. of females No. of males Total No. of females Total No. of males BG1 Brunker St BG Trap + CO2 31-Jan-17 1-Feb-2017 0 0 1 0 0 0 1 0 1 2 1 0 0 0 0 0 0 0 0 0 0 0 4 2 BG2 Brunker St BG Trap + CO2 31-Jan-17 1-Feb-2017 1 0 1 0 0 0 3 0 3 4 0 0 1 0 1 0 1 0 1 0 1 0 13 4 BG3 Ayawarra Cres BG Trap + CO2 1-Feb-17 2-Feb-2017 0 0 1 0 0 0 1 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0

BG4 Smith St BG Trap + CO2 30-Jan-17 31-Jan-2017 0 0 0 0 1 0 3 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 9 0

BG5 Ayawarra Cres BG Trap + CO2 30-Jan-17 31-Jan-2017 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 4 2 1 0 0 0 8 2

1 0 3 0 1 0 11 0 13 6 1 0 1 0 1 0 5 2 2 0 1 0 40 8

TOTALS

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FIGURE 1: Alyangula exotic mosquito survey 30 January to 2 February 2017 -

larval survey sites.

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FIGURE 2: Alyangula exotic mosquito survey 30 January to 2 February 2017 -

CO

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baited BG adult mosquito trap sites.

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Fig 3: Typical elevated house in Alyangula (lawn sprinkler in foreground)

Fig 4: Boat (aluminium dingy) stored under trees in Alyangula found to be positive for Ae. notoscriptus and Cx.

quinquefasciatus larvae

Fig 5: CO2 baited BG trap set at Alyangula residence for 24hr period to catch adult mosquitoes

Fig 6: Nursery in Alyangula with styrofoam boxes containing plant cuttings, and other water holding containers found to be positive for Ae. notoscriptus and Cx. quinquefasciatus larvae

Fig 7: Mining truck tyres stored at the GEMCO mine site.

Nil mosquitoes were found breeding in these large tyres

Fig 8: Plastic bollards holding rainwater at Alyangula wharf found to be positive for Ae. katherinensis and Ae. tremulus larvae

Fig. 9 Biosecurity sticker to prevent water from entering the barriers