Symtomet kan komma från en infektion.

Because the noun is ett symptom in the indefinite form, but in the definite singular it becomes symtomet.

This is a common pattern with some -um nouns in Swedish:

• ett symptom → symtomet
• ett museum → museet

So the -um often changes to -om before the definite ending -et.

The ending -et is the definite article for many ett nouns. It means the.

So:

• ett symptom = a symptom
• symtomet = the symptom

Unlike English, Swedish usually adds the definite article to the end of the noun instead of putting a separate word before it.

In Swedish, nouns belong to two grammatical genders:

• en-words
• ett-words

These genders are mostly something you have to learn with each noun.

In this sentence:

• en infektion = an en-word
• ett symptom = an ett-word

That is why they take different articles:

• en infektion
• ett symptom

And in the definite form:

• infektionen = the infection
• symtomet = the symptom

Kan is the present tense of kunna, which usually means can, be able to, or sometimes may/might depending on context.

In this sentence, kan shows possibility:

• Symtomet kan komma från en infektion.
• The symptom can come from an infection.
• More natural English: The symptom may be caused by an infection or The symptom could come from an infection.

So here kan is not mainly about ability. It is about what is possible.

It is both literal and idiomatic.

Literally, komma från means come from.

But in sentences about illness, causes, or sources, it often means:

• originate from
• be due to
• be caused by

So in this sentence, komma från en infektion means that the symptom has its source in an infection.

This is normal Swedish main-clause word order:

• Subject: Symtomet
• Verb 1: kan
• Infinitive: komma
• then the rest: från en infektion

A useful rule is that in a normal main clause, the finite verb usually comes in second position. Here the finite verb is kan.

So the structure is:

• Symtomet | kan | komma från en infektion

This is very typical Swedish sentence structure.

Because after a modal verb like kan, Swedish normally uses the infinitive without att.

So:

• kan komma
• vill komma
• måste komma
• ska komma

Not:

• kan att komma ❌

This is similar to English:

• can come
• not can to come

You should say Symtomet, not Symptomet.

And yes, a similar sentence is:

• Symtomet kan bero på en infektion.

That means:

• The symptom may be due to an infection.

The difference is small:

• komma från = come from / originate from
• bero på = depend on / be caused by / be due to

In medical contexts, bero på is often very natural.

Från usually means from and marks the source or origin of something.

Examples:

• Jag kommer från Sverige. = I come from Sweden.
• Lukten kommer från köket. = The smell comes from the kitchen.
• Symtomet kan komma från en infektion. = The symptom can come from an infection.

So here från en infektion tells you the possible source of the symptom.

Because the sentence is talking about an infection in a general sense, not a specific infection already known to both speaker and listener.

Compare:

• ...från en infektion = from an infection
  any infection / one possible cause

• ...från infektionen = from the infection
  a specific infection already identified

So the indefinite form fits the general meaning better.

A rough guide for an English speaker:

• Symtomet ≈ SYM-too-met
• kan ≈ kahn
• komma ≈ KOM-ma
• från ≈ frohn
• en ≈ often a short en
• infektion ≈ in-fek-SHOON

A few helpful notes:

• y in Swedish is not like English y. It is a rounded vowel, somewhat unfamiliar to English speakers.
• å sounds roughly like the vowel in British law for many learners.
• tion in infektion is pronounced like shoon.

A more approximate full pronunciation could be:

• SYM-too-met kahn KOM-ma frohn en in-fek-SHOON

It is a normal and common word in Swedish, especially in health-related contexts. It is not too technical.

You can hear it in everyday speech, for example:

• Vilka symptom har du? = What symptoms do you have?
• Feber är ett vanligt symptom. = Fever is a common symptom.

You may also sometimes see symtom in Swedish. That spelling is also used. In modern Swedish, symtom is often preferred by some style guides, but symptom is still widely understood and seen.

Yes. All three can work depending on the tone of the English translation.

• can = very direct, common dictionary translation
• may = often sounds more natural in careful or medical English
• might = slightly more tentative

So these are all possible translations:

• The symptom can come from an infection.
• The symptom may come from an infection.
• The symptom might come from an infection.

If you want the most natural English in a medical explanation, may or might is often a good choice.