Some neurological deficits have been associated with jaguar pythons, a morphological variant of the coastal carpet python (Morelia spilota mcdowelli sub-species). These deficits can range from those that are so mild they are essentially non-detectable, to animals that move in a spinning, back-flipping or corkscrew motion. More subtle effects can include poor coordination, striking aim, or "righting ability" (keeping their head level when turned over).
The vast majority of jaguar pythons have the milder forms of these deficits, barely noticeable unless the animal is handled. In the opinion of some breeders, even jaguars that appear totally normal are a little "less athletic" than most carpet pythons.
These neurological deficits can be present upon hatching, or in some cases, develop years later. One hypothesis is that the "jaguar gene" is coupled with a vulnerability to neurological problems, and that these problems do not appear unless the animal undergoes some kind of stress. The majority of jaguar pythons that develop these effects seem to display them at an early age (less than a year). In most jaguars, these neurological effects may vary a bit over the lifetime of the snake, but do not appear to significantly deteriorate over time. They do not appear to effect the overall health or breeding ability of the jaguar python, nor is their any predictable pattern of inheritance for progeny that have come from a neurologically affected sire or dam jaguar python.
For more information on the history and genetics of the jaguar python, read this excellent summary from Eric Burke:
In December 2017 I discovered nidovirus infection in my python collection. Nidovirus is an RNA virus that can cause fatal respiratory infection in pythons. To contain this infection I tested all the pythons in my collection and have separated the collection into two separate rooms - animals that have tested positive are separated from those that are negative. The rooms are separated by two floors and each room is independently equipped. I am treating my pythons as two separate collections, and do not go into the room with positive animals on days I am working with the negative-tested collection. Animals are fed on separate days. I am also following a number of other quarantine techniques to keep the negative tested collection from becoming positive. Any python sold from Morelia Trophy Club will be verified nidovirus negative by laboratory testing prior to sale.
Nidovirus is working it's way into a number of python collections. It is difficult to know the extent of the problem as some people that are selling pythons are not testing for nidovirus or are not transparent about nidovirus in their collection. Also, a python can be positive for nidovirus without showing signs of infection. This means pythons are being sold that are positive for nidovirus without the buyer knowing this status. Without very strict protocols for containing nidovirus, it can destroy an entire python collection. Now more than ever it is essential to have trust in the people from which you are purchasing a python. I believe it is very important to become knowledgeable about nidovirus and to thoroughly question the nidovirus protocol of anyone from which you intend to buy a python.
For a recent article on inoculation of nidovirus in ball pythons, check out this publication in Virology Journal (2018):