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NSW Arbovirus Surveillance & Vector Monitoring Program |  |
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NSW Arbovirus Surveillance & Vector Monitoring Program | |
 2001 - 2002
Annual Report  |
Mosquitoes were collected overnight in dry-ice baited EVS type traps. They were then sent live in cool, humid eskies via overnight couriers to the Department of Medical Entomology at Westmead Hospital for identification and processing for arbovirus isolation. The mosquitoes were identified via taxonomic keys and illustrations according to Russell (1993, 1996), Dobrotworsky (1965), Lee et al. (1980 – 1989) and Debenham et al. (1989).
Mosquito abundances are best described in relative terms, and in keeping with the terminology from previous reports, mosquito numbers are depicted as:
'low' (<50 per trap),
'moderate' (50-100 per trap),
'high' (101-1,000 per trap),
'very high' (>1,000 per trap), and
‘extreme’ (>10,000 per trap).
All mosquito monitoring results (with comments on
the collections) were placed on the NSW Arbovirus Surveillance Web site, and
generally were available within 1-2 days of receiving the sample into the laboratory.
Access to each location's result is from:
http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/results/results.htm.
Results. Overall, 129,835 mosquitoes
representing 52 species were collected in NSW during the
2001-2002 season. Culex annulirostris was the
most abundant and most important of the inland mosquito species during the summer months. Ochlerotatus vigilax, Coquillettidia linealis, Verrallina funerea and Culex annulirostris were the most numerous species
on the coast.
INLAND. Mosquito collections across the inland where well down with the dry, cool weather and only around 40% of mosquitoes were trapped compared to the previous season, although there were less locations for 2001-2002. Populations were especially low and well below average early in the season, up until late January. While some sites recorded ‘very high’ collections of over 1,000 mosquitoes, even these were often well below the long term average. A total of 58,884 mosquitoes, comprising 23 species was collected from inland NSW. Culex annulirostris was the dominant species trapped at most sites and generally comprised from 60-90% of the collections. Anopheles annulipes was the next most common species.
COASTAL. Only six locations undertook trapping from the coast. Rainfall patterns along the coast were drier than normal for much of spring and early summer, which was reflected in the mosquito numbers that were mostly average to below average. Some 'higher' tides coupled with summer rainfall led to some large collections in February. In total, 61,088 mosquitoes comprising 45 species were collected from coastal NSW. The most common species collected were Ochlerotatus vigilax and Coquillettidia linealis, followed by Verrallina funerea and Culex annulirostris.
METROPOLITAN SYDNEY. A similar trend to the coastal sites was observed within the Sydney region, with mosquito numbers peaking in late February/early March. Other than for this period, collections tended not to be extraordinary. A total of 9,863 mosquitoes, comprising 23 species, was collected from metropolitan Sydney. Depending on the trapping location, different species dominated the mosquito fauna; in western Sydney, freshwater species, such as Culex annulirostris, were the most common, whereas in the Concord/Parramatta/Ryde area, saltmarsh species, such as Ochlerotatus vigilax and Culex sitiens, predominated. The domestic breeding mosquito Ochlerotatus notoscriptus was routinely trapped in both regions.
A brief summary of the surveillance for each location follows the Sentinel Chicken Flock section. Note that complete mosquito monitoring results are available on the NSW Arbovirus Surveillance web site.
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