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NSW Arbovirus Surveillance & Vector Monitoring Program |  |
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NSW Arbovirus Surveillance & Vector Monitoring Program | |
 2001 - 2002
Annual Report  |
Albury: collections were well below average,
particularly at the start of the season. Some ‘high’ collections were made from
the Sewage Treatment Plant during January to March, but mostly numbers were ’medium’.
The Water Pump Station consistently trapped ‘low’ numbers. No viruses were
isolated.
Bourke: mosquito numbers peaked in early March
with one trap approaching ‘very high’ numbers, with Culex annulirostris and Culex quinquefasciatus dominating. During March,
mosquito collections continued to be ‘high’, while at other times they tended to
be ‘medium’ to ‘high’. One isolate of Edge Hill was made from Culex annulirostris collected 13/March. There were
no flavivirus seroconversions in the sentinel chickens.
Condobolin: trapping
was irregular and mosquito collections tended to be well below normal. The March
collections resulted in some ‘high’ numbers from the Sewage Treatment Works, but
generally mosquito collections were only ‘medium’. No viruses were isolated.
Deniliquin: in contrast
to the big collections made early in the season last trapping year, collections were
‘low’ up until late January and well below average. Some ‘high’
mosquito densities were recorded during February, but the totals from both sites were
consistently below average. No viruses were isolated nor were there any flavivirus
seroconversions in the sentinel chickens.
Forbes: no mosquito collections were made this
year and only seven collections from the sentinel chickens were made, with no
seroconversions detected.
Griffith: mosquito
numbers were well below average through the entire season and it wasn’t until early
January before the first ‘very high’ collection was made. Some ‘very high’
numbers were collected from January to March, although these were again well below the
norm. There was one unknown isolate from Culex
annulirostris trapped at Hanwood on 11/2/2002. No flavivirus seroconversions occurred
in the sentinel chickens.
Lake
Cargelligo: some ‘high’
mosquito collections were trapped through February and March, however numbers were below
average, especially early in the season. No viruses were isolated nor were there any
flavivirus seroconversions in the sentinel chickens.
Leeton: overall mosquito catches varied
substantially between the two trapping sites, but were mostly below average. Only on two
occasions numbers reached ‘high’ at Mountford Park, and were otherwise ‘medium’.
Almond Rd trapped much greater numbers, with a ‘very high’ collection of over
8,000 mosquitoes in January. Due to vandalism, this trap site was repositioned to a much
less productive location in mid-February, where numbers never rose above ‘high’.
There were 21 unknown isolates, all from Almond Rd, with 11 from mosquitoes trapped
7/1/2002 and the remaining 10 from mosquitoes trapped 29/1/2002. No flavivirus
seroconversions occurred in the sentinel chickens.
Macquarie
Marshes: trapping
began in February when mosquito collections yielded ‘low’ numbers. ‘High’
collections were recorded through March, although numbers failed to come close to the
‘very high’ collections of the previous season. There was one unknown isolate
from Culex annulirostris trapped on 11/3/2002.
No flavivirus seroconversions occurred in the sentinel chickens.
Menindee: in light of
the flavivirus activity of the previous season, mosquito trapping recommenced at Menindee.
Collections were consistently ‘high’ up until January, although dominated by Culex quinquefasciatus. Thereafter, were ‘low’
to ‘medium’ and below average. No viruses were isolated nor were there any
flavivirus seroconversions in the sentinel chickens.
Tamworth: trapping
was conducted only over three weeks and numbers tended to be ‘low’. There were
viruses isolated from the mosquitoes.
Wanaaring: mosquito
collections were ‘high’ in December, although dominated by Culex quinquefasciatus, and again ‘high’
in early February, with Ochlerotatus eidsvoldensis
being the predominant mosquito. With the dry weather, numbers declined and were mostly
‘low’ to ‘medium’, although there were some large collections of Ochlerotatus eidsvoldensis in late March. There was
one Ross River virus isolated from Ochlerotatus
eidsvoldensis trapped on the 11/Feb.
Wee Waa: only four collections from the sentinel
chickens were made, with no seroconversions detected.
Coastal Locations
Ballina: mosquito
numbers up until February were slightly below average and dominated by Verrallina funerea at Greenfield Rd and Culex sitiens at North Creek Rd. Thereafter,
collections were ‘high’ and generally above average for the remainder of the
season, with Culex sitiens, Ochlerotatus multiplex and Verrallina funerea being the dominant species. No
virus isolation was undertaken.
Batemans Bay: trapping
was conducted on only three occasions; twice in mid-February and once in mid-March.
Although numbers were below average, there were three Ross River virus isolates from the
mosquitoes collected on the 13/2/2002; two were from the Council Depot site and one from
the Mogo State Forest. All isolates were from Ochlerotatus
vigilax.
Gosford: mosquito
collections were ‘low’ to ‘medium’ through to January and around
average. From then on, numbers increased dramatically towards the end of February, where
they were ‘high’ and over ten times greater than normal. These collections were
dominated by Ochlerotatus vigilax and Ochlerotatus notoscriptus. Numbers soon declined
and were around average by mid-March. No virus isolation was undertaken.
Port Stephens: numbers
collected in the mosquito traps were around average up until mid-February for most sites,
although some large numbers of Ochlerotatus vigilax
were trapped in mid-January. Mosquito populations were thereafter above average to
mid-March, with a series of ‘very high’ collections. These were dominated by
both freshwater species (notably Culex annulirostris,
Coquillettidia linealis and Ochlerotatus procax) and saltwater breeding
mosquitoes (Ochlerotatus vigilax). No virus isolation was undertaken.
Tweed Heads: collections were around average for most of the season, however some
‘high’ numbers were trapped in January and February, with large numbers of Culex sitiens. No virus isolation was undertaken.
Wyong:
trapping generally yielded ‘medium’ to ‘high’ mosquito numbers up to
January and then was around average for the remainder of the season. The early ‘high’
collections were comprised mostly of Ochlerotatus
notoscriptus. No virus isolation was undertaken.
Sydney Locations
Blue
Mountains: only four
collections were made this season, which yielded ‘medium’ to ‘high’
numbers dominated by Ochlerotatus notoscriptus.
There were no mosquito isolates.
Concord: mosquito collections were somewhat down
upon recent years, with mostly ‘low’ to ‘medium’ numbers, although
several ‘high’ collections were made at Powell’s Creek following Ochlerotatus vigilax hatching. No virus isolation was undertaken.
Hawkesbury: no mosquito
collections were undertaken this season.
Parramatta: the
insecticide treatments of Ochlerotatus vigilax
breeding sites at Homebush Bay continued this season, ensuring that the big collections of
1997-1998 were not repeated. George Kendall Reserve yielded the majority of the
mosquitoes, with mostly ‘high’ numbers between January and March. Ochlerotatus vigilax was the most common mosquito
species trapped at this site. For the other trapping sites, numbers tended to be ‘low’
to ‘medium’ and usually dominated by the freshwater breeding mosquitoes Culex annulirostris and Ochlerotatus notoscriptus. There was one unknown
isolate from Anopheles annulipes trapped at
Carson St on 12/2/2002.
Penrith: limited collections were made this year,
with traps set on only six occasions. The trapping yielded ‘low’ to ‘medium’
mosquito numbers. No isolates were made from the mosquitoes (although see discussion for
details of an mosquito/arbovirus investigation undertaken at the ADI site, Werrington,
where there were several arboviruses isolated).
Ryde: the majority of
the trapping yielded ‘low’ to ‘medium’ mosquito densities, with some
‘high’ collections, notably from Wharf Road, due to breeding of Ochlerotatus vigilax in association with the spring
tides. Only the Lambert Park collections were processed for viruses, and none were
isolated.
