Frog secretions may be used as mosquito repellent.

Repellents that are currently available are either synthetic chemicals, such as DEET, or plant derived chemicals such as Citronella. Various formulations of these repellents are available that differ in the amount of active ingredient, which is the substance that actually repels the mosquito. These products are available as sprays, wipe-on's, sticks, foams, and lotions.

Researchers from the University of Adelaide have been experimenting on the Australian dumpy tree frog, whose secretions were found to be more effective at warding off mosquitoes, when compared to an untreated sample group

In the study, mice given these secretions remained bite-free for approximately 50 minutes compared to 12 minutes for the untreated group.

Additionally, two other species - the desert tree frog and Mjoberg's toadlet - released mosquito repellent odour from their skin, although their secretions were not tested.

However, the scientists warned that such repellents would only have a limited effect in fighting malaria as mice given DEET, the chemical that is typically used in commercial mosquito repellents, were protected for up to two hours.

Frogs have been the subject of many experiments of this kind as previous research had uncovered that their secretions can act as powerful painkillers and hallucinogens.

Researchers have been trying to find a more natural-based alternative for some years now as continued use of chemical repellents have raised numerous health concerns.

The US Environmental Protection Agency (EPA) has determined that the normal use of DEET does not present a health concern to the general US population and is not classifiable as a human carcinogen.

The American Academy of Paediatrics updated their recommendation for the use of DEET products on children (2005) to state that repellents containing DEET with a concentration of 10 per cent appear to be as safe as products containing a 30 per cent concentration when used according to the directions on the label.

They suggest that it is acceptable to apply repellents with low concentrations of DEET to infants over 2 months old. Non-DEET repellents have not been as thoroughly studied as DEET, and may not be safe to use on children. There are no reported adverse events following use of repellents containing DEET in pregnant or breastfeeding women.

Malaria, which rivals HIV/Aids as the world's most deadly infectious condition, is estimated to kill as many as 3 million people are every year and as many as 300 million cases are reported each year, mostly in tropical areas of South America, Africa and Asia.

Victims experience chills, fever and sweating. If left untreated, the parasite can cause kidney and liver failure, coma and death.

Despite the promise of this new research any new alternative to synthetic repellents would most likely be plant-based, which are considered more practical than animal based ones because the plants were more readily available.

The research appears in the latest issue of the Biology Letters​ journal