Learn Spanish (Latin America): El brote se propaga debido a la higiene inadecuada. - The outbreak spreads due to inadequate hygiene.

We use debido a because it is directly followed by a noun phrase (la higiene inadecuada). You only use debido a que when you are introducing a clause with a conjugated verb, such as debido a que la higiene es inadecuada.

Since this is a negative situation, could we use por culpa de instead of debido a?

Yes. While debido a and a causa de are neutral ways to express cause, using por culpa de is very natural here because an outbreak is clearly a negative event. However, you would not use gracias a, because that connector is reserved for positive outcomes.

Why is there a se before propaga?

The verb propagarse is used here to show that the action happens on its own, without a specific external agent doing it. While English simply says the outbreak "spreads," Spanish frequently uses se to make verbs intransitive, focusing on the subject undergoing the change.

Why is there a la before higiene when the English translation just says "inadequate hygiene"?