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You are having fever which is intermittent,there are many causes of fever like malaria
,UTI,LRTI,TB, and Typhoid(Enteric Fever
Your widal test
titre of 1:40 is not significant.so as to diagnose Enteric fever which depends on clinical correlation.
This test is not useful as many false positive results are seen and blood culture
is better in first week.
A rising titre is more significant.to have some significance it must be 1:160 .
You should visit good Physician and after examination and appropriate investigations once diagnosis is confirmed it can be treated easily.
Please do not ignore your health some times fever may indicate some serious disease.
Please take care