MARC

Mosquito and Arbovirus Research Committee

Our research

MARC exists because local governments realise that effective mosquito control and disease prevention is based on a sound understanding of mosquitoes and virus biology.

By pooling resources to fund research projects of common interest, MARC members have direct access to research scientists, specialised equipment and infrastructure.

Our scientists

As part of our dedication to high quality research, we employ a full-time research officer in the role of MARC Scientist.

The MARC Scientist is based primarily in the Mosquito Control Laboratory at the QIMR Berghofer Medical Research Institute and works in lab and field-based settings to research mosquitoes and mosquito-borne viral diseases that are of public health importance in Australia. Collaborative research projects between MARC and QIMR Berghofer provide the MARC Scientist with access to the Institute's dedicated insectary and laboratory facilities, as well as specialised technical advice.

MARC also supports:

  • A number of postgraduate students undertaking Masters and PhD degrees within QIMR Berghofer's Mosquito Control Laboratory.
  • Mosquito related research at the Griffith School of Environment at Griffith University.

Research themes

Our research is guided by the following list of research themes. Our members review these themes on a regular basis.

The following five themes emerged after MARC members met on 4 June 2014 to update our research priorities. At this meeting, chaired by Professor Scott Ritchie, each member in attendance submitted the three mosquito control issues most pertinent to their own program.

In addition to these themes, the MARC Scientist continues to work with councils on individual mosquito control issues.

Ross River virus (RRV) is the most common mosquito arbovirus affecting humans in Australia. The transmission cycle of RRV and also Barmah Forest virus (BFV) is complex, with at least a dozen likely vectors (e.g. Culex annulirostris, Aedes procax, Ae. vigilax, Ae. notoscriptus, Coquilletidia linealis).

The recent 2014-2015 RRV outbreak across Southeast Queensland featured cases uniformly distributed across the region, suggesting that widely-occuring, freshwater mosquitoes (e.g. Cx. annulirostris, Ae. procax) may have played a major role.

Another factor may be the emergence of a susceptible reservoir host population. Potential vertebrate reservoir hosts include macropods, possums, horses and fruit bats. By identifying local vertebrate hosts of RRV and BFV (e.g. by serosurvey), it may be possible to design strategies for disease control that are specific to the locality and mosquito and host species in question.

Analysis of spatial and temporal data may shed additional light on RRV epidemiology.

Urban development is bringing human population into closer contact with mosquito habitat. Developments near breeding sites (e.g. coastal marshes and mangrove swamps) will create potentially unbearable mosquito (and/or biting midge) nuisance situations for residents in the new developments unless effective measures are taken. These may include barriers and buffer zones, but their efficacy has not been evaluated, particularly for long-dispersing mosquito species such as Aedes vigilax.

Developments also incorporate a number of different water sensitive urban design (WSUD) structures, such as swales and bioretention basins, in an effort to improve the quality of storm water discharge. Incorrect design and maintenance of these structures can result in the creation of temporary freshwater pools, which can be highly productive for freshwater vector mosquito Culex annulirostris.

In addition, little consideration has been given to the long-term impact of water storage (i.e. rainwater tanks) on vector populations. Establishing the extent of mosquito breeding in newly installed rainwater tanks and older tanks, including possible design or installation faults associated with mosquito production will help to establish the current and future risks of installation.

Southeast Queensland is challenged by the risk of incursion of two invasive mosquito vectors: Aedes aegypti and Ae. albopictus.

Ae. aegypti, the primary dengue vector, was present in Brisbane into the 1950s. It is not entirely clear why the population disappeared, but there is no reason to think it could not reestablish. Likewise, Ae. albopictus, never having established on mainland Australia, is highly invasive and present throughout the Torres Strait islands.

Southeast Queensland requires a container-breeding mosquito surveillance program both in and outside of first ports of entry. Required research includes progress in surveillance (e.g. detection of eggs, detection of DNA in water, GAT traps, rainwater tanks, water-filled roadside barriers) and control.

Adulticides, barrier/harbourage spraying, vehicle-mounted sprays, and metofluthrin/spatial volatiles issues require evaluation.

Mosquito management programs in Southeast Queensland emphasise larval control in breeding sites with the use of target-specific compounds such as Bacillus thuringiensis israelensis (Bti) and S-methoprene, but there are also situations where adult management is appropriate. Barrier or harbourage treatments may be effective where residential zones are adjacent to breeding sites that are inaccessible for larval control, but the efficacy of these treatments need to be evaluated.

There is also an interest in the efficacy of residual spraying in quarantine situations (e.g. airports), especially with regards to mosquitoes (e.g. Ae. aegypti) having immigrated from areas with significant insecticide resistance.

Finally, more recent insecticidal chemistries, such as the spatial volatiles metofluthrin or transfluthrin, may have indoor and outdoor applications against mosquitoes or biting midges.

Two freshwater mosquitoes implicated in the transmission of Ross River virus (RRV) are Culex annulirostris and Aedes procax.

Immature stages of Cx. annulirostris occur in a number of habitat types including temporary grass-dominated pools and permanent freshwater ponds, often on private land. Local governments require a greater understanding of the characteristics of the most productive larval habitats.

The ecology of Ae. procax habitat is poorly described. Although Ae. procax may be abundant in light-trap collections, little is known of chemical susceptibility or optimal environmental conditions. Definition of the aquatic habitats of Ae. procax, along with confirmation that Ae. procax transmits RRV and/or Barmah Forest virus (BFV) in the field will facilitate the development of effective control strategies to prevent human infection.