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NSW Arbovirus Surveillance & Vector Monitoring Program |  |
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NSW Arbovirus Surveillance & Vector Monitoring Program | |
 2000 - 2001
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).
Following a revision of the genus Aedes and its subgenera, several subgenera have been raised to generic rank and the new names will be used from the beginning of the 2001-2002 season. Appendix I lists those species from NSW in which the name has been altered.
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, 214,496 mosquitoes representing 67 species were collected in NSW
during the 2000-2001 season. Culex
annulirostris was the most abundant and most important of the inland mosquito
species during the summer months. Aedes vigilax,
Coquillettidia linealis, Aedes funereus and Culex annulirostris were the most
numerous species on the coast.
INLAND. Across the inland, mosquito collections tended to follow a similar trend; numbers were extremely high and well above average following the heavy October/November 2000 rainfall. With the hot and dry conditions in January, mosquito abundance declined rapidly, and continued to remain below average for the remainder of the season, with the continuing dry autumn. A total of 144,780 mosquitoes, comprising 24 species were 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. The number of coastal trapping locations was reduced this year to five locations, with no monitoring locations from the southern regions. Rainfall patterns along the coast were more stable and closer to normal, which was reflected in the mosquito numbers that were mostly average. High tides coupled with summer rainfall led to some large collections particularly in late February and again in early April at many sites. In total, 52,669 mosquitoes comprising 43 species were collected from coastal NSW. The most common species collected were Aedes vigilax and Coquillettidia linealis, followed by Aedes funereus 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 to be not extraordinary. A total of 17,047 mosquitoes, comprising 30 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 was the most common, whereas in the Concord/Parramatta/Ryde area, saltmarsh species predominated, including Aedes vigilax and Culex sitiens. The domestic breeding mosquito Aedes 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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