Ha bolhát látok vagy oltás kell, akkor az állatorvoshoz megyek.

Ha means if, and akkor means then.

So the pattern is:

• Ha X, akkor Y = If X, then Y

In Hungarian, akkor is often used to make the structure clearer, but it is not always strictly necessary. You could often leave it out in everyday speech:

• Ha bolhát látok vagy oltás kell, az állatorvoshoz megyek.

That still sounds natural. Including akkor just makes the conditional relationship more explicit.

Because bolhát is in the accusative case, which marks the direct object.

• bolha = flea
• bolhát = a flea / fleas, as the thing being seen

In látok (I see), something is being seen, so Hungarian marks that noun with -t:

• bolhát látok = I see a flea / fleas

The extra vowel before -t appears because Hungarian often inserts a linking vowel to make pronunciation easier.

This is a very common Hungarian question, because Hungarian has two main verb conjugations:

• indefinite conjugation
• definite conjugation

Here:

• látok = I see (indefinite)
• látom = I see it / I see the specific one (definite)

Even though bolhát has object marking, it is still indefinite because it means a flea / fleas, not the flea.

So:

• Bolhát látok. = I see a flea / fleas.
• A bolhát látom. = I see the flea.

This is one of the trickiest things for English speakers, because English does not have this kind of verb distinction.

Because Hungarian verb endings usually already show the subject.

• látok = I see
• megyek = I go

So the pronoun én (I) is usually omitted unless you want emphasis or contrast.

For example:

• Látok = I see
• Én látok = I see / I am the one who sees

Hungarian is very comfortable leaving subject pronouns out when the verb ending makes the subject clear.

Literally, oltás kell means:

• vaccination is needed
• or more naturally, a vaccination is needed

Hungarian often uses kell (is needed / must) with a noun, not just with an infinitive.

So:

• oltás kell = a vaccination is needed
• oltani kell = it is necessary to vaccinate / one must vaccinate

Both are possible, but they are structured differently.

In your sentence, oltás kell treats vaccination as the thing that is needed.

Because both are being used in a general, non-specific way.

• bolhát látok = I see a flea / fleas
• oltás kell = a vaccination is needed / vaccination is needed

Hungarian often omits the article when the noun is indefinite or used in a general sense.

Compare:

• Bolhát látok. = I see a flea.
• A bolhát látom. = I see the flea.

And:

• Oltás kell. = A vaccination is needed.
• Az oltás kell. = That/the vaccination is needed.
  This would sound much more specific.

The ending -hoz means to / toward in the sense of going to a person or place.

• állatorvos = veterinarian
• állatorvoshoz = to the veterinarian

So:

• az állatorvoshoz megyek = I go to the veterinarian

Hungarian often uses case endings where English uses prepositions.

The ending changes by vowel harmony:

• -hoz
• -hez
• -höz

Here it is -hoz because that fits the vowels in állatorvos.

Hungarian has two forms of the definite article:

• a before a consonant sound
• az before a vowel sound

Since állatorvoshoz begins with the vowel á, the correct article is:

• az állatorvoshoz

Compare:

• a kutya = the dog
• az állatorvos = the veterinarian

This is similar to English a/an, but only for the definite article.

Here vagy means or, and it links two alternatives:

• bolhát látok = I see fleas / a flea
• oltás kell = a vaccination is needed

So the sentence means:

• if I see fleas or a vaccination is needed, then I go to the vet

In Hungarian, vagy can connect either simple words or whole clauses, just like or in English.

The sentence as given is natural and straightforward, but Hungarian word order is more flexible than English word order.

The neutral version is:

• Ha bolhát látok vagy oltás kell, akkor az állatorvoshoz megyek.

You can sometimes move things around for emphasis, for example:

• Ha bolhát látok vagy oltás kell, az állatorvoshoz megyek.
• Akkor az állatorvoshoz megyek, ha bolhát látok vagy oltás kell.

These all express basically the same idea, but the emphasis may shift slightly.

Hungarian word order often reflects focus and emphasis, not just grammar.

Megyek is the 1st person singular form of menni (to go).

So:

• megyek = I go / I’m going

That matches the speaker in the sentence:

• látok = I see
• megyek = I go

Hungarian verbs carry a lot of information in their endings, so one word often corresponds to an English pronoun + verb combination.

It can mean either, depending on context.

• bolhát látok can be understood as I see a flea
• but in context it may also mean I see fleas

Hungarian often does not force the same singular/plural distinction that English does in this kind of indefinite expression. If the speaker wants to be clearly plural, they can say:

• bolhákat látok = I see fleas

But the singular indefinite form can still be used in a more general sense, especially when talking about noticing the problem.

Yes. Both are possible, but they are slightly different.

• megyek az állatorvoshoz = I go to the vet
• elmegyek az állatorvoshoz = I go off / I’ll go to the vet

The version with el- can sound a bit more like a concrete action or decision.
The plain megyek is simpler and very natural here.

So the original sentence is perfectly good, but Hungarian often uses verbal prefixes to add nuance.