Biting midges (commonly called sand flies) are from the family of insects known as Culiocoides. There are over 270 species of Culiocoides in Australasia with three main species causing annoyance to humans. Culiocoides spp (nr subimmaculatus) is widely distributed, Culiocoides ornatus occurs in areas north of Tin Can Bay in Queensland, and Culiocoides molestus occurs in canal estates. These pests all have marine associations and are not known to transmit any diseases to humans. Barmah Forest virus has been isolated from Culiocoides marksi but this species rarely bites humans. The anatomy of their feeding mechanism means that (unlike mosquitoes) they leave a large raised mark on the skin that is filled with damaged tissue and saliva (containing anticoagulants). This can cause certain individuals repeatedly exposed to their bites to become “sensitised” and trigger allergic responses. The direct impact on human health and wellbeing caused by midges is due to the allergens in midge saliva.
These biting insects are an annoyance to humans, but are not likely to transmit disease. Biting midges become a public health issue when residential property developments occur close to midge-breeding sites resulting in increased human – midge interaction. The biting midge problem within the Byron Shire community has not been quantified. Biting midges are insects that breed in wet soils in the tidal zones such as mangrove mud and sandy shores. These insects are also important components of our valuable estuary tidal marsh and mangrove ecosystems. Biting midges are attracted to human habitation and rest on screens, fences and vegetation while waiting to take a blood meal. As the biting midge is small and easily blown about by prevailing winds, they prefer dull still days with high humidity when seeking a meal. There are four species that have been identified as the main cause of midge problems in the North Coast of NSW. They are Cullicoides molestus, Cullicoides subimmaculatus, Cullicoides longior and Lasiohelia townsvillensis.
Further information can be found by accessing the Tweed Shire website. Council recognises the expertise and considerable experience of Tweed Shire entomologist Mr. Clive Easton who compiled the information referred to in the previous paragraph. At this time council has no data on the extent of breeding sites, the particular species involved and size of this problem in Byron Shire. The use of any pesticides in such sensitive ecological environments is also not supported as it is highly likely to cause serious environmental harm. No effective treatment process exists to prevent these insects breeding and travelling to the nearest “blood meal”. Some species can travel up to three kilometres from the breeding sites in search of a “blood meal”. The best remedies for such pests appear to be to keep residences from being located close to breeding sites. Only topical repellents and screening of buildings can provide a measure of protection to humans already located in affected areas.
The issue is primarily one of planning, and the inherent conflicts between humans and the natural environment. A sensible precaution to prevent biting insect attack is to avoid areas that are known to have high biting insect activity. Extensive areas of mangroves or estuarine areas with sandy beaches are potential sources of sand flies and generally residents within 400m of the breeding area can be exposed to them. There can be a downside in living in a beautiful area like Byron Shire, for example for people who want to work or relax in our beautiful outdoors. This downside includes the nuisance factor associated with midges. The growing demand by Australian residents to reside in coastal areas has put pressure on land for housing and many areas have been developed near midge breeding sites. Like mosquitoes, the female biting midge takes a blood meal to provide protein to develop her eggs. The direct impact on human health caused by biting midge is due to allergens in midge saliva reacting on people of varying degrees of sensitivity and immunity.
Most people find the bites uncomfortable and distressing with the irritation leading to scratching and sometimes infected sores. Biting midges are not known to carry any diseases affecting humans in Australia. There are three major pest species of estuarine breeding biting midge affecting coastal areas. There are also a forest breeding species which seasonally affects other areas of the Shire. Following are some suggestions to help alleviate or minimise midge problems. Midges are very active during dawn and dusk, and the problem is most prevalent in suburbs located close to mangroves and inter-tidal zones.Have your sayWhat was your experience? Do mozzies love or loathe you? Tell us on the messageboard below. There's no doubt mosquitoes prefer some people over others, but can vitamin B turn someone who is usually a target for mosquitoes into a turn-off.Although this home remedy is often espoused in the popular press there's no solid scientific evidence to back it up.
Medical entomologist Dr Cameron Webb says taking vitamin B before your next BBQ will do little to keep mosquitoes at bay.He says while some people are more attractive to mosquitoes others simply have a stronger reaction to mosquito bites. It's a reaction to the mosquito's saliva – injected during the bite – that gives you an itchy lump the next day, like all allergic reactions, the severity varies from person to person.There are a number of other variables that can affect our reaction to bites including how repellent each mosquito finds us, the species of mosquito that is biting us and where we are bitten (as in geographical location Sydney vs Cairns).Given that mosquitoes can be carry some very nasty diseases – in addition to being extremely annoying – it's a good idea to take precautions if you suspect they're around:Finally, if you're travelling overseas make sure you speak to your GP about whether you need any vaccinations or medications for mosquito-borne diseases.Dr Cameron Webb is a hospital scientist with Department of Medical Entomology at Westmead Hospital's Institute of Clinical Pathology and Medical Research.