I don't know about inside but I think Ecns.com has a wrong date for this.

This aircraft was LTM. The first contact with the mouse/rat was on flight to Delhi on 29AUG. 30AUG AY22 was delayed several hours due to chasing this animal.
After that OH-LTM left for PEK 30AUG, to CKG 31AUG, overnight maintenance in HEL 01SEP and 02SEP to CKG as AY55. 03SEP AY56 was cancelled, 03SEP AY61 (AY62 04SEP) got cancelled and 04SEP AY55 was cancelled. AY56 on 05SEP was operated as scheduled.

In July 2015 HEL-PVG passenger reported seen mouse on board and Finnish media reported that this 340-300 aircraft was under Chinese officials quarantine 24 hrs at PVG.