Q: My father has been travelling a lot. He is 71 years old. He was in Chennai when he had fever, about 100 degrees. At that time he had some boils on the back of his thigh and also a toothache. So he attributed the fever to this and took Paracetamol SOS. After returning home the fever continued so a Widal test was done. The results are: Salmo Typhoid O Antigen Positive, 1 in 80 dilution; Salmo Typhoid H Antigen Positive , 1 in 80 dilution; Salmo Para Typhoid AH, BH Negative, 1 in 20 dilution; TWBC Count 7300 cells/cumm; Neutrophils - 61%; Lymphocytes - 34%; Eosinophils - 05%. He was put on Chloromycetin 500 One TDS for a week, then dosage reduced to one BD. After some time the test was repeated and the results were: Salmo Typhoid O Antigen Positive, 1 in 80 dilution; Salmo Typhoid H Antigen Positive , 1 in 160 dilution; Salmo Para Typhoid AH, BH Negative, 1 in 20 dilution; TWBC Count 7400 cells/cumm; ESR (Westergren) 1 hour-22mm; Neutrophils 60%; Lymphocytes 36%; Eosinophils 04%. Continued Chloromycetin 500 twice a day. Widal test was done once again. Results were: Salmo Typhoid O Antigen Positive, 1 in 80 dilution; Salmo Typhoid H Antigen Positive , 1 in 80 dilution; Salmo Para Typhoid AH, BH Negative, 1 in 20 dilution; TWBC Count 7200 cells/cumm; Neutrophils 56%; Lymphocytes 39%; Eosinophils 05%. It looks like he is back to square one, though there is no fever. He has not moved out of his home-town. What medicine should he take? What is the meaning of Typhoid relapse ? How can that be prevented? I will be grateful for your kind advice.

A:Widal test is a poor investigation to diagnose typhoid infection. It takes more than one week for the test to become positive, and there are a lot of false positives and negatives, which are influenced by treatment, time of sampling, immune response, etc. A titre of 1:80 or 1:160 is not considered diagnostic of typhoid. The titre should either show a 4-fold rise at an interval of 2 weeks or a titre of >1:200 is considered presumptive evidence of typhoid. The O agglutinins appear earlier in the infection and disappear earlier too, whereas the H agglutinins take a long time to appear and persist for a long time. It appears that you father's fever is not due to typhoid, but most probably due to either the boils on his thigh or tooth infection. A clinical examination to check these is advisable, and the treatment can be decided after this. Also, get your fathers blood sugar (fasting and post prandial) tested. Simple ways to prevent typhoid fever are to maintain hygiene and drink only clean drinking water, and eat hygienic food. The typhoid bacteria are transmitted through contaminated water and food, so ensuring that you do not eat outside food, especially cold food or where hygiene is not upto the mark, is advisable.