Patient Zero

Patient Zero is a quest to search for Mutalist Alad V, introduced in Update 15.5. Patient Zero is a quest introduced in Update 15.5, where players must find and locate Alad V's new Infested Form to stop his plans of dominating the Origin System.

Walkthrough
This quest can immediately be activated under the Quest tab in the Codex.

Acanth, Eris
The Lotus sends the Tenno to a Corpus Ship in Acanth, Eris to extract data that would reveal what the Corpus know about Alad V, playing out as a Spy mission. The Corpus had been searching for Alad V for months due to his devastating attacks on their ships. Once the second datamass has been collected, Alad V contacts the player about appreciating his "gift" to them, signaling the arrival of Infested units onboard the ship that will fight both Tenno and Corpus alike. The mission ends once all the Datamasses have been brought to extraction.

The data collected from the Corpus reveal that Alad V has gotten hold of another Warframe, with plans to infest it.

Candiru Eris
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It is important to note that the final mission is a nightmare mission that makes you face an Infested Tenno after sabotage is complete, so it may be better labeled as a deception.

It is important to note that the final mission is a nightmare mission that makes you face an Infested Mesa Warframe after the reactor is destroyed, so it may be better labeled as a deception.