Will the Irido viruses be able to infect and kill many of the unique and rare frog species of Australia?
Cane Toads from South America were a failed introduced biological control of the sugar cane beetle.
(The beetles could climb but the cane toads couldn't.)
Where are the vaccines against Irido viruses that should be being developed to safeguard our native frogs?
VIRUS MAY CONTROL TOADS
Article from the The Cairns Post (Cairns,Queensland,Australia)
Tuesday 23 July 1996 Page 7
VIRUS MAY CONTROL TOADS
Australian researchers are trying to isolate a potential "calicivirus" for cane toads to stop the voracious amphibians from frogmarching up to the vulnerable Kakadu National Park in the Northern Territory.
Researchers at the CSIRO’s high security Australian Animal Health Laboratory in Geelong are racing
against the clock to determine whether several viruses isolated from Venezuelan cane toads will stop their Australian cousins dead in their tracks.
The toads were introduced in 1935 to control the cane beetle.They already have decimated water rat,quoll,native frog and some bird populations in Queensland and are capable of wreaking an ecological disaster in the fragile Kakadu ecosystem,experts say.
Although reluctant to release preliminary results at this early stage,Dr Alex Hyatt said the viruses
were believed to attack the tissues and organs responsible for forming blood cells.
Researchers hope blocking the production of toads’ white blood cells could cause a breakdown in their immune systems.
Dr Hyatt,AAHL project leader in electron microscopy and iridoviruses,stressed it was still uncertain whether the viruses,isolated in the Venezuelan creatures were responsible for the more stable South American toad populations."There are no results we’re willing to release yet as this is a complex process requiring an enormous amount of innovation and technology to set up the infrastructure and
diagnostic tests needed to determine immune status" Dr Hyatt said.
But researchers should know by early 1997 whether Australian toads can be targeted.Dr Hyatt said
although myxomatosis and calicivirus had been used to combat rabbit populations,cane toad research
was more complex as it involved pinpointing a specific virus and not working with a known agent.
"And we’re also dealing with an aquatic animal which undergoes metamorphosis in three life stages"
he said.Dr Hyatt said stringent criteria would have to be met before a virus could be released.
Press release - CSIRO (Animal Health)
22 July 1998
Venezuelan viruses ruled out for cane toad control
CSIRO scientists have ruled out the use of viruses from Venezuela to control cane toads in Australia because laboratory trials show that the viruses can also kill native Australian frogs as well as the toads.
Research also shows a small number of Australian cane toads may be carrying a virus similar to the Venezuelan viruses, which could affect Australian wildlife.
The two-year project formed part of a wider research program, led by CSIRO Wildlife and Ecology, to look at the impact and control of the cane toad in Australia.
Research into the potential of viruses to control cane toads involved isolating and purifying viruses from cane toads in their native habitats of Venezuela, in South America. The effects of the viruses on cane toads and native frog species, were then tested in the secure biocontainment facilities at the CSIRO Australian Animal Health Laboratory.
Dr Alex Hyatt from CSIRO Animal Health says viruses isolated from Venezuelan cane toads were compared with other viruses of the same family from around the world, and are believed to all fall within a new species of virus.
While the viruses proved effective in killing cane toad tadpoles, they also killed one species of Australian frog in the trial. Dr Hyatt says the project has increased knowledge about cane toads and their viruses.
As part of the work, the researchers also identified two fungal pathogens that are lethal to cane toads and other amphibians. One fungus is thought to be responsible for frog fatalities in Australia and Panama.
The team found a small percentage of Australian cane toads in the wild had been exposed to a virus similar to the Venezuelan viruses, which are known to cause disease and death in fish and amphibian populations in Australia and overseas. "This adds another dimension to the potential impact of cane toads on the Australian environment," Dr Hyatt says.
The international research team looking into the use of viruses to control cane toads included:
Dr A. Hyatt, CSIRO Animal Health, Australia
Dr T. Robinson, CSIRO Wildlife and Ecology, Australia
Dr C. Musso, Department Micobiologia, Instituto Venezolano de Investigaciones Cientificas, Venezuela
Dr. G. Lopez, Department Micobiologia, Instituto Venezolanao de Investigaciones Cientificas, Venezuela The Federal and State governments provided research funding.
Cane toads were introduced into Queensland in 1935 as a bio-control agent against beetle grubs that were affecting sugar cane crops. The toads did not control the grubs, but have since flourished and extended their range throughout much of Queensland and the Northern Territory.
The cane toad is highly toxic, can compete with native species for food, and is a predator of some native fauna.
Click here to read about possible unknown virus killing frogs and toads 1995
Click here to return to front page