Chester Zoo treats 23-year-old python with electrochemotherapy in veterinary first

Diagnosis and recurrence

Keepers at Chester Zoo in north-west England noticed unusual behavioural changes in Jodie Foster, a 23-year-old reticulated python measuring 4.5 metres in length. The reptile, which weighs between 40 and 50 kilograms according to veterinary records, had become inactive and showed a marked reduction in appetite. Diagnostic testing identified a fibrosarcoma, a malignant tumour located in her jawbone. Surgeons initially removed the growth in 2024, but the malignancy recurred the following year and began destroying bone tissue in the mandible. Because pythons rely on jaw mechanics to consume whole prey, the progressive bone destruction threatened the animal's life by making feeding increasingly difficult. Zoo veterinarians concluded that standard surgery would not prevent another recurrence.

Dr Ian Ashpole, veterinary officer at Chester Zoo, explained the decision to pursue alternative interventions:

We were facing the possibility of losing her as the tumour made it more and more difficult for her to eat, so we worked with cancer specialists to see whether we could adapt electrochemotherapy for a snake. As far as we're aware, this is the first time it's ever been used in one.

Adapted electrochemotherapy procedure

To treat the recurrent tumour, Chester Zoo collaborated with veterinary oncologists from the University of Liverpool's Department of Small Animal Clinical Science. The team selected electrochemotherapy, a clinical technique that combines the anticancer drug bleomycin with targeted electrical pulses. These short, calibrated pulses temporarily increase the permeability of cancer cell membranes, allowing the drug to penetrate more effectively and enabling the use of lower chemical doses. Managing a reptile of this size required specialized surgical logistics. Keepers and veterinary staff first anaesthetised the python inside her enclosure before moving her to the zoo's veterinary centre. Because standard equipment could not accommodate a 4.5-metre snake, two operating tables were pushed together to create a platform comparable in size to a double bed. Staff maintained the cold-blooded animal's core body temperature using warmed air and heated blankets throughout the 90-minute operation. Ashpole first excised the primary tumour mass alongside the damaged sections of jawbone, after which the team administered bleomycin and delivered the electrical pulses directly to the surgical site to eradicate residual malignant cells.

Recovery and scientific publication

Following the procedure, the python underwent monitoring to track wound healing and verify whether she could resume normal feeding habits. Pythons possess flexible jaw joints that allow them to dislocate sections of the skull to ingest large prey. Zoo keepers confirmed that the partial loss of jawbone did not compromise these mechanics, recording footage of the animal striking, seizing, and consuming whole chickens without difficulty. A final veterinary check conducted in August 2026 detected no remaining traces of cancer or further tumour growth.

Electrochemotherapy is an emerging treatment and this was the first time it was used in a snake. The success of this treatment is a testament to the power of collaboration.

Jose Alvarez Picornell confirmed that the clinical team plans to publish the surgical and pharmacological details in a peer-reviewed veterinary journal, providing a documented protocol for clinicians treating similar malignancies in exotic reptiles.