Malformations

Malformations

In January 2003, we received three batches of really sick looking tadpoles, all of which died as tadpoles and some of which were sent to a lab. These were the last remaining tadpoles found in three different backyard ponds. They were grey in colour (the species is usually speckled brown), very sluggish and had pourly formed legs. We asked a virologist to have a look. With the condition they were in, not a lot of testing options were available but sequencing could be done and the result was that they had an unidentified virus. Since then, more virus tests have been performed and two herpes viruses appeared using PCR but little has been done since to progress through further required tiers of testing (no funds).

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Ever since then, we have cataloged a repeating pattern of deformities, malformations, growth deficiencies, colour mutations and symptoms which resemble Metabolic Bone Disease but go way beyond that. We eventually came to name this collection of symptoms the "Redlynch" virus after the suburb the original specimens came from and because virus testing had revealed that at least one virus was present. There may be a lot more to this story however but to prove what is really going on, we need to raise about $20,000 for toxicology work. Why toxo work? Because the viruses present may have only been a secondary matter because of immune deficiency - the real culprit is likely to be chemical. Before you start thinking about farmers, think about domestic households. This problem didn't first appear in agricultural areas - it appeared in residential suburbs UPstream of any agriculture.

After we had a proven pattern of what to look for in both tadpoles and juveniles, a vet lab in Brisbane did some histology on a sick Common Green (White's) tree frog juvenile that had been sourced from south eastern Queensland. We were looking at the details of this case to track incidences of this disease in South Australia and obtained a copy of the lab result. The technician had found a virus in the liver of the animal and we chased him for the clinical presentation. This animal matched the same clinical symptoms we were seeing on juveniles locally. The Brisbane lab then asked CSIRO's animal health lab (AAHL) in Geelong to identify the virus he found. A herpes virus was the answer but formal isololation did not occur.

We have observed a few important basics about this 'condition' even if we don't know the full causitive picture involved:

1
It is aquatic or at least transported by water; water bodies with little flow-through (such as during drought) would have more issues than a regular flowing body such as a stream
2
It looks like it has horizontal transmission (via the water body) but appears strongly to also have vertical transmission (via the eggs from the parents who might be carrying it) Another possibility brought up by a visiting toxocologist from Europe is that it is very possible the parents' DNA has been damaged by chemicals so they now produce 'defective' offspring.
3
Malformations (always with either limbs or eyes) are common so the pathogen (or genetic damage) seems to target the "construction code" of the animal during a time of development
4
The level of stress in the tadpoles or frogs determines when the condition will activate - stressed tadpoles will die from it sooner while stronger tadpoles will survive better but die off as metamorphs or juveniles
5
With the frog species we have seen it in and had in captivity since egg stage, the total die off rate from tadpoles through to juveniles of six months of age is about 90 to 95%
6
If it is caused by a pathogen, we can assume that the pathogen didn't evolve in Central or South America because it is even deadlier in the cane toad than it is the Australian frogs! When we sample cane toad tadpoles from an affected water body, many of them drop dead on the spot; the longest we can keep cane toad tadpoles alive that have this problem is five days so the cane toad has become a very useful sentinel species
7
After collecting over 3,000 'toadpoles', we only managed to keep two individuals alive past metamorphosis and their body colour was based on shades of grey instead of brown
8
We have also collected toad metamorphs from a notoriously prolific cane toad breeding spot in Cairns and what few metamorphs we could find were malformed - when we tried to raise them in captivity, they all died within days
9
What frogs we have been able to keep alive in captivity only grow to about half normal size; their skeletons are warped, they cannot climb and they only stay alive with very regular extra doses of calcicum; with some tree frog species, they are missing either the blue or yellow pigments for what should be a green frog (in other words, L. caerulea's are blue and L. gracilentas and L. xanthomeras are yellow)
10
We have also noted severe reproductive issues with hatching failures and the deaths of entire clutches after only 2 or 3 days

This condition - whatever we might name it - is definitely elsewhere in Australia besides Far North Queensland! We can hardly rescue ANY tadpoles from anywhere in Cairns without finding they have this condition but calls have come in from many other regions reporting the same thing (and we have the documented case of wild tadpoles caught in SEQ and sold interstate). We have received an exceptionally malformed batch of tadpoles from the Lake Tinaroo area in Atherton and reports from the Gold Coast and Sunshine Coasts of SE Queensland. Specimens from Mackay in October 2007 were confirmed by a lab as being the same problem.

We have been contacted by keepers in three states (SA, VIC and NSW) who have animals they have purchsed via the pet trade that have the clinical symptoms of this malformation problem. We have also received reports from several states in the USA which is where we believe this problem might have come from before it arrived here.

We have had four wet seasons in a row with excellent rainfalls and this has flushed many water bodies "clean" so to speak, so reports of this disease decreased but now that we are back into a very dry period from 2012 forwards, reports of frogs at all are becoming scarce. And of course that would be the case when their the populations' recruitment has all but been wiped out!

Since meeting with a European toxicologist in 2013, we have a new, VERY plausible explanation which can be proven if we can do the toxicology testing ourselves. The possibility is that chemicals are damaging the parents and they are producing defective offspring which don't survive. If this is true, this is a staggering issue that threatens to wipe out all amphibians (and we're sure they will not be the only ones impacted).

In the meantime, if you are relocating tadpoles 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.

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:

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1
It is aquatic or is present in water so once it has been transported to a body of water, all tadpoles in it are infected
2
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)
3
It doesn't seem to have any effect on fish so it is unlikely to be a ranavirus/iridovirus (two of the labs that have tested this suggest that it is a herpes virus but we are learning that when an animal has been affected by sub-lethal doses of chemicals (including us), it becomes a sponge for parasites and pathogens, so the viruses found in our animals could be secondary to the primary issue) ).
4
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
5
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:

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1
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);
2
Juveniles can have one deformed eye and we've seen two right arms per socket and three rear legs per socket; juveniles can have one or both eyes missing;
3
The front of the body looks normal while the back half of the body is stunted:
4
The frog only grows to a third or half of normal size or appears to not be growing at all;
5
Scoliosis is common;
6
Rear legs are warped and feet twisting backwards is common;
7
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;
8
The body can get very bloated with fluid (this is from calcium depletion), especially in the older juveniles and sub-adults
9
The colour of some tree frogs is wrong (Graceful remains yellow instead of green, Common Green tree frogs are blue or two-tone);
10
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:

1
Some tadpoles in a batch shift colour from normal to very pale or very dark;
2
Some species turn grey
3
Some tails are stunted in length and rounded instead of pointed
4
Tails get S or L bends in them or are corkscrewed
5
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)

1
The largest of the tadpoles are dead in the water while the smaller ones look fine
2
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
3
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 with only the tadpoles missing
4
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 and contact us right away.

In the long run, this is very likely to involve chemicals and the only way to get to the truth of the matter is to pay for our own toxicology testing. We actually have a very specific chemical group in mind that we suspect is involved based on when certain things were approved for market and when specific types of problems happened in the frogs. We will never be able to raise the money needed from government or foundations so a swell of public support will be needed for this one!

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