The most common and most likely answer to this crossword clue is the 5 letter word POLIO
P
O
L
I
O
More clues leading to the result POLIO
- Disease shown by boil – operable, on reflection
- Disease from India caught by traveller to the East
- One held in car brings complaint
- Winnie briefly taking lithium for serious condition
- Viral infection from India caught by 13th-century explorer
- Promotion of ointment and surgery nearly eradicated virus
- One is in the game despite debilitating disease
- ....interest in a game could be a handicap
Buddy explains!

The straight part
We know that "Viral infection" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case viral infection = polio.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does POLIO mean?
POLIO noun- A sufferer from poliomyelitis.
- Acute infection by the poliovirus, especially of the motor neurons in the spinal cord and brainstem, leading to muscle weakness, paralysis and sometimes deformity.