I have never conducted any formal studies of these treatments I have given in the past. But what I can say is simply this from observations:
I didn't start treating HL's with Panacur until about 2 years into my second HL. This lizard died the following year due to heat stress, but the last year of his life he seemed more active and generally healthier. No other significant conditions about his care had changed in that period. In this first treated animal I had never seen obvious signs of any parasitic infestation, even after several fecal examinations by 10x magnification. I assumed the chances were he was not infested, or that the levels were low. Especially due to the high mealworm and cricket diet he was being given at the time. After Panacur treatment he passed nematodes. No count was taken, but as I recall, it was not a significant amount. Perhaps less than a dozen.
The next 3 HL's were taken in at the same time and not treated initially upon intake. I also made the mistake of not housing them seperately for several weeks as I knew I should have. They showed no casually observable signs of parasitic infestation. The two smaller females became ill, and died within a week of each other. They were not treated prior to their deaths. Necropsy on the second revealed significant presence of nematodes. Many dozen. Necropsy was not conclusive as to cause of death, however, I suspected complications caused by nematodes or gastrointestinal enteritis due to corresponding symptoms in both prior to their deaths. This HL was also the smallest of the three, and there appeared to be areas of injury or discoloration to parts of the bowels and possibly the stomach. I expected that either bacterial or viral enteritis ( inflammation ) or parasites could explain this.
The male was treated immediately for parasites and survived. After initial dose and 2 weeks of observation, no parasites had been passed. Following the second dose, he began to pass nematodes. I place the numbers loosely at a few dozen. He was growing and putting on steady weight after this until hibernation. This HL was treated again prior to hibernation. No significant parasites were observed at that time. However, after emerging from hibernation he weighed in about 10 grams less. Within several weeks after emerging from hibernation, he was treated again. This time the HL passed what I would call a significant and possibly alarming amount of nematodes. Over the course of several weeks he passed nematodes regularly with scat. I place this number easily at 100 or more. Since that treatment he has put the weight back on and has resumed growth. He is alert, active, and healthy in all other manners as I can tell to date. Growing STL by 1.6", STV by .9", and nearly quintupling his weight since hibernation.
Two other wild females taken in for temporary study were also treated recently. Nematodes were passed by both in insignificant numbers. No positive or negative effects were observed. These two HL's also resided in an area which was much less aboundant ( almost devoid ) in harvester ants. Only 3 colonies being found in an area of roughly 30 acres. In captivity they greedily took to harvester ants and everything else offered. In fact, each ( including one juvenile ) eating more harvester ants daily than my solare. On average 100 or more a day.
No other hard data available. However, I maintain anti-parasitic treatment in captive HL's is adviseable due to the numbers of nematodes that can infest them heavily in a short period of time. I have advocated initial treatment upon intake, and twice yearly afterwards. Due to the infrequency of this treatment schedule, I think any risk to HL physiology is negligible compared to possible risks associated with large numbers of parasites.
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"A man that should call everything by it's right name, would hardly pass the streets without being knocked down as a common enemy." The Complete Works of George Savile, First Marquess of Halifax 1912,246
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