Typhoid Tests, Typhoid Fever Testing, Salmonella Typhi Test
Question 1. What is Typhoid Fever?
Typhoid fever is caused by small bacteria which always enter body via food, water or unwashed hands. Once in the body, the bacteria quickly multiply in the gut and causes inflammation of the gut. Some bacteria may escape the gut and gain entrance into blood and invade other organs such as liver, brain and joints. More often the bacteria cause the body’s immune system to mount an inflammatory response with increased chemicals that causes headache, low blood pressure, fever, and septic shock.
Question 2. When should I suspect if I have Typhoid Fever?
Typhoid fever is very common in our community and if left untreated it is not only life threatening but also very infectious that it can be transmitted easily or passed on to another person or family member. You should have typhoid fever test checked if you have the following:
Abdominal pain
Profuse diarrhoea that hasn’t settled for 2 or 3 days.
High Fever
Loss of appetite
Headache for the first time
Nausea and vomiting
Unwell and lethargy for no apparent reason
If you came in contact with someone with typhoid fever, you may have the bacteria without a complaint.
Question 3. How is typhoid fever Diagnosed?
Blood, stool or Urine Culture: -Definitive laboratory diagnosis involves culture of bacteria in stool, blood and occasionally in urine.
Blood Antibody /Widal test: This is simple and available in most major health facilities and hospitals . Widal test looks for antibody to typhoid fever as a marker of infection. In order to confirm diagnosis, a repeat testing one week apart is required. Very high antibody levels are seen in typhoid fever.
Blood or stool Antigen Kit Test: Recently, new rapid diagnostic kit that looks for parts of bacteria (antigen) in stool or blood is available. This test is more specific and easier to do in any centre with minimal training. However, it is still relatively expensive costing around K5-10 per test at the moment.
Question 4. How is the test performed?
A small blood sample of about 5-10mls is taken. No special preparation is required. Same sample can be used to do other basic chemistry tests including kidney, liver, pancreas, diabetes, gout, calcium , cholesterol and cancer blood tests. For more accurate diagnosis, stool sample is required.
Question 5. Is there any pitfall to the tests?
Widal test is not specific and can be positive in patient with rheumatoid arthritis or even malaria, for example. Hence laboratory diagnosis is based in change in titre and importance of repeat test 1-2 weeks apart for confirmation. However, if you have classical symptoms of typhoid fever, you should still have antibiotic treatment if test shows positive. The antigen test looking for bacteria in stool is more specific and accurate in confirming the diagnosis.
Question 6. How long before the results available?
Widal antibody and rapid antigen kit tests are very simple to do and takes only few minutes. Results are usually ready on the same day depending on laboratory workload and procedure. You may return to your doctor on the next appointment day for discussion of results. Culture test looking for signs of bacterial growth usually takes 48-72 hours but may take up to a week for antibiotic testing.
Question 7. What does the test report mean?
Widal results are reported as positive or negative. For more definitive diagnosis the laboratory will perform antibody titre. This is the amount of antibody against typhoid that is present in your blood. An increasing (rising) antibody titre over few days apart must be demonstrated to confirm active infection. In active infection rising antibody titre is observe. For example, from 1: 80 to 1:160 or over must be on repeat testing.
Two types of antibodies are detected; one against common typhoid antigen called anti-O and the other against flagella antigen called anti-H. Very high or rising anti-O titre occurs in active infection whereas high or rising anti-H titre occurs in carriers of typhoid infection.
For interpretation of results you should review with your doctor so appropriate treatment can be given. Typhoid bacteria are very contagious and can easily be transmitted from one person to another. Your close contacts especially your family members will also need typhoid screening perform if you are infected.
Question 8. What is the Treatment?
Typhoid Fever treatment is simple if diagnosed early. You will be given antibiotics for 2-3 weeks. In PNG, chloramphenicol is widely used for treatment of typhoid fever. New antibiotic such as ciprofloxacin is very effective in treating typhoid fever. In addition, you should also maintain good fluid balance and health eating habits. It is very important to wash your hands before eating and after toilet. This not only helps prevent transmission but also re-infection. Always eat freshly prepared food and avoid food that is unhygienic in preparation.
Question 9. My doctor says my typhoid Blood Test is still positive. Should I get repeat treatment?
It is important to note that common blood test in PNG is Widal antibody tests which is not a good test for typhoid fever. Typhoid antibody test will remain positive for many months even after you have been cleared of typhoid infection. Ask your doctor if your antibody tests level has changed significantly from the previous test? The best thing would be for your doctor to take stool sample for detection of actual bacteria (via rapid tests kit or culture) instead of blindly giving you another lot of antibiotics to take.
Question 10. Should I have my family screened for Typhoid Fever?
Typhoid fever is contagious and can easily pass from one person to another via poor hygiene or food and water. Since one can carry the bacteria without symptoms, anyone in close contact with typhoid fever patients should be tested for typhoid fever. The best screening test for this is stool culture or antigen detection test. Widal antibody test is not good for identifying someone who has the bacteria but is not showing signs of infection such as fever, diarrhoea and headache.
Question 11. Is there a vaccine available?.
Yes. You can be vaccinated against typhoid fever. There is an oral as well as injection form of vaccine available. Unfortunately, this can only be bought privately as it is not yet available through public health services.
