Wrong widal tests have contributed to the misdiagnosis and poor management of typhoid fever in Nigeria, Daily Trust investigations have shown.
A medical laboratory scientist, Ndubuisi Ebitea, said the widal test is not a diagnostic test for typhoid fever, and that there was actually an abuse of the test because “it doesn’t tell much, it just tells you that you have been exposed to the bacteria.”
Typhoid fever and malaria are estimated to constitute about 50 percent of all hospitalisation in tropical countries like Nigeria.
However, the kind of test commonly used to diagnose the disease in the country especially when done repeatedly, exposes people to misdiagnosis, and wrong treatments.
Mr Ebitea said tests that detect whether someone has typhoid fever, include blood culture, and stool culture. He said the widal test only checks for the antibody, salmonella typhi that causes typhoid.
Typhoid fever is a life-threatening infection caused by the bacterium, Salmonella typhi. The common symptoms include stomach pains, headache, and loss of appetite.
The medical director of Kawo General Hospital, Kaduna, Dr. Oyelami Akintunde, said Samonella typhi and para typhi bacteria are the cause of enteric fever also known as typhoid fever. He said that it was a water borne disease transmitted via feaco-oral route that is, through ingestion of contaminated food or water.
“With the rainy season in the last few months, sources of water are heavily contaminated with defecation and sewage, thus, increases rate of spread,” Dr. Oyelami Akintunde said.
“Also, the mode of diagnoses (widal test) which is not reliable and indiscriminate use of antibiotics by the populace to treat the disease leads to drug resistant strain and increase in the incident of the disease,” he said.
He said the present economic situation in the country indirectly contributes to rise in cases of typhoid fever where quality of food and food products being ingested by the populace was low and in unhygienic environments, adding that the rise in consumption of bottled and sachet water make people drink water from contaminated sources.
Widal tests everywhere
Findings by Daily Trust reveal that when people are diagnosed of typhoid fever using widal tests, the number of people who test positive were usually far higher than when the same persons were subjected to blood culture or stool tests.
According to Dr Izedonmwen Omo, a public health physician, people are usually asked to go and do typhoid fever and malaria tests when they go to the hospital based on the symptoms they present and their complaints.
He said the disease was not as prevalent as people think saying that the common practice of asking people to do widal test for typhoid fever, and the rate of positive results produced was what gives the perception about the high prevalence rate in the country.
Omo added that the specific diagnostic test for typhoid fever is the blood culture test.
Ebitea who is also the Chairman of the Association of Medical Laboratory Scientists of Nigeria (AMLSN), Federal Capital Territory (FCT) chapter said “it is the widal test that doctors usually request. When the result is positive, after the first treatment, they are supposed to request for either stool culture, blood culture or even urine culture, but instead, they repeat request for widal test.”
“And when they make that request for widal test, that test is still going to come back positive because what they are checking for is an anti-body not whether the organism is present,” he said.
The medical lab scientist said that by repeating requests for widal test, clinicians abuse the test, stating that in the health facility where he works for instance , throughout 2016, the laboratory worked on about 3,600 stool samples, and got only two salmonella positive test results meanwhile if it was widal test, the estimate would have been as much as 40-52% of the sample figure.
He said it was important for medicals officers and clinicians to understand the relevance of the different tests they request.
The National Chairman of the Association of Community Pharmacists of Nigeria (ACPN), Dr Albert Kelong Alkali, said typhoid like other diseases could only be properly treated when there was right diagnosis, adding that when the test requested was not right, the drugs administered would not work because the person may be suffering from another illness. He also advised against self medication.
Data obtained by Daily Trust from different hospitals across the country showed a wide disparity between the number of people diagnosed with typhoid fever with widal tests and those diagnosed from other confirmatory tests such as blood or stool culture tests.
At Aminu Kano Teaching Hospital, Kano (AKTH), statistics showed that 569 suspected cases of typhoid fever were recorded between January and June this year.
The Acting Head of Microbiology Department of the hospital, Dr Edwin Chinagozi who disclosed this to Daily Trust said 199 cases tested positive through widal test method while nine patients were isolated through blood culture and stool respectively.
He said the figure may not be accurate reflection of real typhoid cases in the health facility due to some limitations inherent in widal test by which patients test positive as a result of their previous exposure to salmonella.
“Because of the nature of our setting most people have been exposed in one way or the other ,some even when they have being cured of the disease, the anti-bodies still remain in them and thus they test positive when widal test is used,’’ he said.
In the last six months, Jos University Teaching hospital (JUTH) recorded 38 patients infected with typhoid from various tests.
Out of the 38 patients, the hospital’s Assistant Director, and medical lab scientist, Angela Nedolisa, said 29 patients, ranging between the ages of 10 to 75, “had significant widal test titre,” while the hospital recorded nine patients with the disease from blood culture test, while none was diagnosed within the period through stool culture. One patient diagnosed with perforated typhoid was admitted in the hospital in the month of May.”
Data obtained from Dr Dalhatu Arab Specialist Hospital, Lafia, Nasarawa State revealed that between January and May this year, a total of 774 people were diagnosed positive with typhoid through widal titre. Out of this figure, a total of 187 were confirmed through culture of having salmonella typhi.
While a total of 134 were admitted for typhoid fever in the hospital between January and May this year, a total 17 persons died of typhoid within the period.
Available data from the Parklane Teaching Hospital, Enugu showed that from January to May 2017, 1,158 patients tested positive to typhoid fever.But the data did not to indicate what kind of tests were used to arrive at the results.
Data obtained from Zankli Medical Services Limited, Abuja showed that 1,125 people tested positive to typhoid fever through widal test from December 2016 to May 2017 while only five tested positive through stool culture and none through blood culture.
Also data collated from General Hospital, Kawo, Kaduna, revealed that a total of 408 persons were diagnosed with typhoid fever through widal test while 68 were diagnosed through stool test from January to May, 2017.
Meanwhile, a total of 145 people were admitted in the hospital due to typhoid fever from January to May this year.
At the Federal Medical Centre Lokoja, a total number of eight patients tested positive to typhoid fever through culture in the last one month while a total number of 18 patients did Widal test with 1/640 rise in titre, and repeat widal test was done.
Stool culture preferred
A Consultant Pediatric Surgeon and Acting Head of Clinical Services at the hospital, Dr Taiwo Jones Olaoluwa said the hospital does not rely on the results of widal tests in treating typhoid cases because it is not a specific diagnostic tool for typhoid fever.