My Husband Has Fever In Frequent Intervals, He Felt Nauseous

my husband has fever in frequent intervals, he felt nauseous for the first couple a days, severe body pain, shivering and fever in the evenings, headache, fatigue. all these symptoms are there from saturday afternoon, we did a WIDAL today morning and the result has come as negative. it means he has no typhoid ???? but his symptoms are present. what condition is this ????