Kelambu dan ubat nyamuk melindungi kami daripada nyamuk.

Because the two instances do different jobs:

• ubat nyamuk is a fixed noun phrase meaning something like mosquito repellent or mosquito insecticide
• daripada nyamuk means from mosquitoes

So even though the same word appears twice, it is not redundant in Malay. The first nyamuk helps describe what kind of ubat it is, and the second nyamuk names the thing being protected against.

Kelambu means a mosquito net, usually the net hung around a bed or sleeping area to keep mosquitoes away.

It is a specific noun, not just any kind of net.

The base word is lindung, which has the idea of protect / shelter.

In this sentence, melindungi is the normal active verb form used when the verb takes an object:

• melindungi kami = protect us

Very roughly:

• lindung = root
• meN- turns it into an active verb
• -i often helps form a transitive verb that acts on an object

So melindungi is the natural form for protecting someone/something.

Malay distinguishes two kinds of we/us:

• kami = we/us, not including the listener
• kita = we/us, including the listener

So melindungi kami means protect us, where us does not include the person being spoken to.

If the speaker wanted to include the listener, they would say melindungi kita.

Here daripada means from or against, in the sense of protection from something harmful:

• melindungi kami daripada nyamuk = protect us from mosquitoes

This is a very common pattern in Malay:

• melindungi seseorang daripada sesuatu

In standard Malay, daripada is often preferred for non-physical from meanings, including things like source, comparison, or what something is protected from.

So in this sentence, daripada nyamuk is the standard choice.

A useful rough guideline is:

• dari → often for place, direction, or time
  
  • dari rumah
  • dari pagi
• daripada → often for people, sources, comparisons, or abstract relations
  
  • daripada Ali
  • lebih besar daripada
  • melindungi kami daripada nyamuk

In everyday speech, people do not always keep this distinction perfectly, but this sentence uses the standard form.

Yes, it is very similar here:

• Kelambu dan ubat nyamuk = subject
• melindungi = verb
• kami = object
• daripada nyamuk = prepositional phrase

So the structure is basically:

Subject + Verb + Object + From-phrase

That is one reason this sentence feels quite straightforward for English speakers.

Malay verbs do not change for singular or plural the way English verbs sometimes do.

So:

• Kelambu melindungi kami
• Kelambu dan ubat nyamuk melindungi kami

The verb melindungi stays the same.

Malay also does not change verbs for person in the way English does:

• I protect
• he protects

In Malay, the verb form stays the same.

Literally, yes:

• ubat = medicine / remedy / chemical treatment
• nyamuk = mosquito

But in actual usage, ubat nyamuk usually means something like:

• mosquito repellent
• mosquito spray
• mosquito insecticide
• mosquito coil, depending on context

So it is best understood as the normal Malay expression for something used against mosquitoes, not medicine for sick mosquitoes.

Malay usually does not use articles like English a/an/the.

So:

• kelambu can mean a mosquito net or the mosquito net
• ubat nyamuk can mean mosquito repellent, a mosquito repellent, or the mosquito repellent

The exact meaning depends on context.

That is very normal in Malay, and learners should not expect articles to appear the way they do in English.