Sandflies typically arrive one or two at a time. They quickly build to a swarm encircling the victim. They seek exposed skin, where the female saws a hole through the outer derma with a mouth shaped like a bread knife. Bleeding begins and a collection of blood is formed. The sandfly drools while it laps up this blood pool and its drool contains an anti-coagulant called histamine that prevents the blood from clotting. Agglutinins prepare the pooled blood for digestion and are also deposited on the skin.
It is this histamine and agglutinins mix that causes the red bumpy reaction in the victim's skin.
Sandflies tend to feed on tourists and new arrivals while locals seem to build some type of internal resistance to sandfly bites. Sandfly swarms can arrive quickly. Having a sandfly defense plan will help.
Ten sandfly defense tricks
- Wear a hat covered with some type of sandfly deterrent. Goodbye Sandfly, tea tree oil, eucalyptus oil and citronella oil all have some success.
- Take vitamin B. This defense works for both mosquitoes and sandflies. Vitamin B capsules, Marmite, Vegemite, and brewer’s yeast all contain high levels of vitamin B that will help deter sandflies. The effects of vitamin B can most easily be seen when standing with a group of non-vitamin B eaters.
- Bug protect your ankles with socks or some bug repellant. Sandflies tend to start their attack at the ground level and work upward
- Wear light colored clothes. Sandflies are attracted to dark clothes.
- Walk. Sandflies are very slow creatures. As long as you are moving they can't swarm.
- Keep your motorhome or caravan closed up. Sandflies are notorious for their ability to find openings to enter and lie in wait.
- Plan the day to spend sunrise and sunset geared up for sandfly defense
- Sandflies are attracted to heat. Turn off needless lights during dusk.
- Sandflies can follow a carbon dioxide trail hundreds of metres. If dense bush is located directly downwind, consider moving.
- The first defense is to segregate the living space. Hanging mosquito nets between cabins helps reduce the spread. A mosquito net draped over a hatch, window, or door allows easy access, but prevents most sandfly entry. A mosquito bed net is an elegant solution for a peaceful nights sleep.
Quick sandfly eradication
Sandflies are attracted to heat. A simple method of clearing sandflies from a living space is to turn on a single light. Force the sandflies into the air by walking through the cabin swinging a duster or magazine. Pay particular attention to the corners and areas under shelves. The airborne sandflies become attracted to the light and begin to circle. As the sandflies surround the light they become easy pray for a quick smash against the light housing.
Citronella oil repels and even kills sandflies. Citronella oil lamps placed upwind can help to deter a sandfly attack. Citronella candles burned inside the vehicle or cabin a half hour before entry can kill most of the errant and hiding interior population. Remember to keep an eye on the open flame.
Other tactics
Opening back windows and taking a drive can suck the errant sandflies out of a vehicle. Sandflies don't like heat. Closing up a vehicle or boat in the sun for a short period can kill the complete invasion.
Sandfly tidbits
Sandfly density can overwhelm local cattle due to anaphylactic shock. Even the human population is not immune. In Canada, for example, trade unions have negotiated into their contracts clauses that prevent work when sandfly densities reach epidemic proportions.
New Zealand sandflies don't carry any known diseases that effect humans. They do, however, carry a form of bird malaria that affects penguins.
Goodbye Sandfly reports it's better to open an upwind window in a living space. If you open the downwind window, sandflies collect in the eddy created and enter the space. Simple net curtains can do wonders for keeping an inside space comfortable.
Sandflies are particularly susceptible to insecticides, but spraying has not seemed to reduce their population. One report from Columbia sent scientists to local homes where the inside walls were sprayed with insecticide. Test traps collected in the homes showed almost no reduction in sandfly population. It was thought that the density of sandfly populations in the bush was so great that they simply "re-filled" the "kill zone".