Pant has been advised rest, but his illness isn't very serious, according to a BCCI official, and the decision to have reinforcement was precautionary, considering there was no other full-time wicket-keeper in the 15-member squad. Sudip Chatterjee, the Bengal batsman, kept wickets in Pant's brief absence on the third day of the first Test last week.
Should Pant recover, there is a possibility of both him and Parthiv featuring in the pink-ball match starting September 30.
Pant, who wasn't part of the four-day fixtures in South Africa last month, struck a counter-attacking 41-ball 67 in the first Test, which India A won by an innings and 31 runs. He has, however, been an India A regular in the one-day format recently.
Meanwhile, Parthiv's inclusion is perhaps an indication of the selectors' decision to look at options for the second wicketkeeper, behind Wriddhiman Saha, ahead of the South Africa tour in January.
The 48th Indian to complete 10,000 first-class runs during the Duleep Trophy earlier this month, Parthiv is coming off a memorable 2016-17 season in which he captained Gujarat to their maiden Ranji Trophy title.
Midway through the season, he also earned a Test recall after eight years, for two matches against England. He sustained his form through the IPL, scoring 395 runs for Mumbai Indians in a victorious campaign.
Parthiv's last fixture for India A was against the visiting Australians in a three-day rained-out fixture in Hyderabad in 2008.