New Problem: "Redlynch" virus

This problem is getting around fast and we ask anyone relocating tadpoles to PLEASE STOP.

If you are a breeder of frogs and have experienced any batches of tadpoles which have the symptoms described on this page, DO NOT SELL OFF OR GIVE AWAY ANY OF THAT BATCH. We can assist you with decontamination information as well as contacts to have some of the diseased batch examined for confirmation that they are affected with this virus.

"Redlynch" virus is definitely getting around! Aside from the Cairns' suburbs of Redlynch, Centenary Park, Ellis Beach, and north of Ellis, we are getting new reports of dead and deformed tadpoles from Clifton Beach, Smithfield, Upper Mooroobool and Whitfield. We are also receiving problematic tadpoles from Mena Creek and Mt. Carbine which are two remote areas nowhere near Cairns. We are also receiving reports from several states in the USA which is where we believe this problem came from before it arrived here.

Other reports we have received indicate that the problem is also present in the Atherton area and the Gold Coast and Sunshine Coasts of SE Queensland. We received a report of this virus in the wild in Mackay in October 2007. Sadly, we have also had confirmation that this disease is in the pet trade in Victoria and South Australia and we know of at least two breeder's premises which are contaminated and at least one VIC and two SA pet shops that have sold juveniles with "Redlynch" virus. In late 2007, reports started coming in from NSW as well with clearly infected offspring coming from a breeder's premises.

CSIRO is currently working on the process of formal identification and characterisation of this virus and results are expected in early 2008. But there are some specific predictable symptoms and behaviours we have been able to record so far.

Please look at your backyard water bodies for any of the indications below and contact us asap if you see anything fitting the descriptions below:

• it appears to be aquatic so once it has been transported to a body of water, all tadpoles in it are infected
• it might also have vertical transmission which means an infected adult automatically passes the virus to its offspring through the process of reproduction (which would explain why the virus has turned up in very temporary, isolated bodies of water such as a puddle in the lawn when heavy rain has fallen)
• it doesn't seem to have any effect on fish so it is unlikely to be a ranavirus/iridovirus (one of the labs that has tested this says that it is a herpes virus)
• it doesn't start to cause physical changes or sudden death until the mid to later stages of tadpole development so the young ones appear perfectly normal
• it causes the majority of the clutch (roughly 90%) to die before metamorphosis; dead tadpoles nearing the stage of metamorphosis can be found floating at the edge of the water or dead on the bank just after metamorphosis

What few juveniles that do survive past metamorphosis are deformed and/or suffering growth problems - some common indications in frogs are:

• all four limbs are disfunctional, ranging from weak to completely uncoordinated
  (with tree frogs, some tadpoles are unable to climb out of the water at all and drown);
• juveniles can have one deformed eye and we've seen two right arms;
• juveniles can have one missing eye;
• the front of the body looks normal while the back half of the body is stunted:
• the frog only grows to a third of normal size or appears to not be growing at all;
• scoliosis is common;
• rear legs are warped and feet twisting backwards is common; when legs are tucked in (normal position), the ankles stick out slightly to the back and the knee joints are bent upward, the feet might stick out perpendicular to the calf instead of lining up under it;
• the body can get very bloated with fluid, especially in the older juveniles and sub-adults
• the colour of some tree frogs is wrong (Graceful remains yellow instead of green,
  Common Green tree frogs are blue or two-tone);
• sudden death continues to plague juveniles in first six months; almost all raised in
  captivity die with a average of one per clutch reaching breeding age (and only because it is protected in captivity - deformed individuals would not last long in the wild)
  

In the tadpoles, the signs to look for are:

• some tadpoles in a batch shift colour from normal to very pale or very dark; some species turn grey
• some tails are stunted in length and rounded instead of pointed
• tails get S or L bends in them or are corkscrewed
• behaviour gets sluggish and they stop eating

In a water body, the signs to look for are: (this applies to flowing creeks as well as enclosed water bodies)

• the largest of the tadpoles are dead in the water
• heaps of tadpoles are present one week (but nowhere near the stage of metamorphosis) and it seems they have all or mostly all vanished as little as a week later
• lots of frogs are calling frequently at the water body but there are no tadpoles to be found in the water - other marine life is there so it is not a toxicity issue
• the only tadpoles you can find after doing regular searches are the smallest ones

Cane toads are especially susceptible to this problem and mortality rates at the tadpole stage are nearly 100%. If any cane toads are found with even the slightest deformity to their legs, eyes, or backs, please collect them for us.

We would like to ask everyyone to please do some checks on the water bodies which may be on your properties and, if any of the indications listed above are present, please contact us asap. We will want to collect a batch of tadpoles from your water to raise in captivity so we can monitor and record the symptoms. (If the problem with your tadpoles turns out not to be disease, we can advise you on setup changes you can do to improve tadpole survival.)

Last updated: December 5th, 2007