The casualty included two leopard cubs, four spotted deer, two sambar deer, one Malabar giant squirrel and a 13-day-old hippo cub.
With the death of the leopard cubs, the total number of the wild cats has come down to five, zoo sources said.
The leopard cubs, Sarishma and Asha, died after being infected with the Feline Panleukopenia Virus (FPV), commonly known as 'cat plague'.
Most of the deer were victims of a contagious disease spread by flies which extract blood from its hoofs.
However, B Joseph, the Director of the zoological park, said the issue of animal deaths was a "bit exaggerated" as most of them had died due to age-related ailments.
"It is true that the leopard cubs died due to FPV, which affects the cat family. But, many deer had died due to age-related ailments. The case of Malabar squirrel was also not different. The hippo cub was killed after it was kicked by its mother hippopotamus under water," Joseph told PTI.
In the wake of the deaths, an experts' panel, comprising officials of animal husbandary department and veterinarians, has been set up to study the issue and suggest remedial measures, on instructions from Minister for Zoos and Museums P K Jayalakshmi.
"Incessant rain is a major reason for the spread of disease-causing flies in the animal enclosures. It is also a major hurdle for taking up hygienic measures," Joseph said.
Established by Travancore King Swathi Thirunal Rama Varma in 1857, the Thiruvananthapuram Zoo is located in a 55 acre campus in the heart of the city.
The green-rich park, which houses large number of animals like lion, tiger, leopard, rhinoceros, Asiatic lions, elephants, and zebras besides birds like Indian Peafowl, White Spoonbill and Cassowary, is frquented by holidayers and nature buffs.