Answer:
A parasitic bacteria contaminated her food.
Step-by-step explanation:
A parasitic organism is that which derives nutrients from another, usually called a host, by harming it. In this case of Arainne who fell sick after traveling abroad and eating different countries' food, it indicates that a microbe that is harming her (leading to health complications) has contaminated her food.
Contrary to a parasitic organism, a mutualistic and commensalistic organism will not cause harm to any organism they interact with. Only a parasite will deteriorate the health and physical well being of its host in the process of obtaining nutrients. A predatorial organism kills its pretty, which is not the case here.
Therefore, Arianne's current health condition is as a result of the contamination of the food she ate by a parasitic bacteria.