The Parasitism 3 contract is a priority task to finish for the Sekiguchi faction in Marathon, and there are three parts to complete.
Compared to the second contract, the third one is slightly trickier unless you know where you need to be. Let’s look at how to complete the contract by finishing all three tasks in a single run.
Table of contents
Marathon Parasitism 3 contract walkthrough
The Parasitism 3 contract can be broken down into three tasks.
- Loot Sparkleaf in Dire Marsh
- Extract Biotic Sample from Sparkleaf in Bio-Research
- Inject the synthesized sample in central Quarantine, then exfil
How to loot Sparkleaf in Dire Marsh

For the first task, you need to find a Sparkleaf that grows in the wild. They don’t have any fixed location, and you can find them frequently on your run. You can refer to the image above to know what it looks like. Once you pick the Sparkleaf and add it to your inventory, you can proceed to complete the remaining tasks.
How to extract Biotic Sample from Sparkleaf in Bio-Research

The next task is to extract the Biotic Sample from your extracted Sparkleaf. Head ot the Bio-Research POI located in the eastern part of the map. Once you’re at the marked location, you’ll find a big building as shown in the image below.

Take the ladder on its side and head to the upper floor. Enter through the door (right at where you get up from the ladder), and you’ll find the terminal to extract the Biotic Sample from the Sparkleaf.
How to inject the synthesized sample in central Quarantine

For the last task, head to the Quarantine POI and reach the marked location. You’ll find a small room, and the quest marker will appear, which highlights the location of the terminal. Place the Biotic Sample in the terminal, and it will provide the synthesized sample.

Inject yourself with the synthesized Biotic Sample, and escape the map unharmed to complete the Parasitism 3 contract. Once done, you’ll have two more contracts remaining to complete in this series.