Nigeria: It's Not Typhoid - Tackling Misdiagnosis of Typhoid Fever in Nigeria

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Editor's Note: This week's blog is a personal story from a Nigeria Health Watch team member, Patience Adejo. She writes about her experience being diagnosed with Typhoid Fever multiple times using the Widal test, only to recently learn that the test does not give the most accurate diagnosis for typhoid fever. She delves into the standard procedure for diagnosing typhoid fever in Nigeria and the need for renewed scrutiny and adherence to diagnosis guidelines.

Growing up in a family of five children, I was tagged with the nickname 'Healthy Patty' because I was so full of energy and hardly ever got sick. All that changed in May 2017 when I started to have constant headaches every day, coupled with a general feeling of malaise, dizziness and a high temperature. I visited the hospital many times and each time I was asked to do a Widal test, this always produced very high titre values. Widal Test is a simple laboratory test used to determine if a patient has typhoid. It works by forming tiny clumps which show the presence of the bacterial agent in the patient's blood. The amount of clumps formed is used to determine the severity of the infection.

The doctors repeatedly diagnosed me with typhoid fever following the results of the Widal test. This was until February 2019 when a follow-up stool, blood and urine culture was done to confirm the diagnosis. Imagine my surprise when the results from the culture contradicted the most recent Widal test that had been carried out just four days before! The Widal test was positive for typhoid, and the stool urine and blood culture tests were negative for typhoid. My ordeal at being repeatedly misdiagnosed with typhoid following 10 Widal tests over a 22-month period is an indication that the Widal test, while easy and low cost to administer, is not reliable in the diagnosis of typhoid fever and this has most likely led to a large number of patients being misdiagnosed and treated for a disease they never had.

Dr Ada Amajor, a general practitioner who used to work in Maitama General Hospital, Abuja said that the Widal test was never designed for diagnosis, but was initially used as a presumptive test for enteric fever, also known as typhoid fever. It was used to identify people who had been exposed to the Salmonella entericaserotype Typhi (S. typhi) bacterium, usually spread through contaminated food and drink, as well as faeces.

There is widespread misuse of the Widal test as many physicians diagnose and treat typhoid cases based on results from a single Widal test that they administer when previous episodes of typhoid have been treated. In addition, exposure to the typhoid vaccination can cause a Widal test to give a false positive result. False diagnoses and treatment of typhoid fever with antibiotics does not help in the battle against antimicrobial resistance, a major challenge in the world today. Research suggests that in typhoid-endemic regions like Nigeria, single testing of a serum specimen for Widal agglutination cannot provide a reliable diagnosis.

Studies have shown that patients who present with symptoms similar to typhoid may have diseases like malaria or urinary tract infections. One study actually showed a significant association between the severity of malaria parasitemia and a positive Widal agglutination test. If these infections are not first ruled out before clinicians diagnose for typhoid, false positive Widal reactions are inevitable.

In a study published by a Nigerian Medical Journal in June 2016, 271 blood samples from consecutive adults (>18 years) with febrile illness attending the General Practice Clinic of the University of Benin Teaching Hospital were tested using the Widal agglutination test, blood culture, and malaria parasite test on each sample to establish the diagnosis of typhoid fever. Of the 271 blood samples 124 (45.76%) were positive following a Widal agglutination test, 60 (22.10%) blood samples grew Salmonella organisms on blood culture while 55 (20.29%) blood samples showed a co-infection of typhoid fever and malaria.

The World Health Organisation (WHO) has stated that the Widal test, should not be used as a diagnostic tool for typhoid. WHO suggests that a blood culture before initiating antimicrobial therapy remains the diagnostic method of choice, although the isolation of Salmonella typhi from the bone marrow is the standard method for confirming a typhoid case.

Dr Amajor agrees that the standard tests for typhoid are blood culture, stool culture, and urine culture. She said that these tests are seldom done due to issues around lack of efficient laboratories or diagnostic centres; delays in producing results; the patient's inability to pay for tests; and physicians poor knowledge of the uses of the Widal test and its limitations. Health Maintenance Organisations (HMOs) in addition have declined to cover the cost of the Widal test as they do not view them as a reliable test for typhoid diagnosis.

Many health practitioners that we spoke to, did not seem to be aware of any national guideline for the diagnosis and treatment of typhoid in Nigeria and so they relied on the WHO guidelines for the diagnosis and treatment of typhoid fever. Even though the WHO guidelines state clearly that the Widal test is not a diagnostic test, it is still widely used in many health facilities.

The Standard Treatment Guideline developed by the Federal Ministry of Health in 2008 also states clearly that "A positive culture is the 'gold standard' for the diagnosis of typhoid fever. Specimens for culture may be obtained from the blood, stool, urine, bone marrow, gastric and intestinal secretions." It lists the Widal test as a non-specific investigation stating that the 'Widal test gives high rates of false positives and negatives, and the guidelines emphasise that "there are no diagnostic tests for typhoid fever other than positive cultures."

The thought of being on antibiotics almost every two months for almost two years is harrowing for most people. Yet this was my experience until stool, urine and blood cultures were taken that contradicted the Widal test. This experience is even more unpleasant as I realise that I may never even have had typhoid. The urine culture eliminated typhoid, but an infection was diagnosed which according to the doctor could have been the cause of the high titres the Widal tests showed.

Still, millions of Nigerians are being misdiagnosed with typhoid due to the use of the Widal test. Clearer diagnosis and treatment protocols should be given to health professionals at all levels. The Standard Treatment Guidelines are over 10 years old and have not been updated since. More responsibility and leadership is needed in this area. Although many doctors and hospitals in Nigeria do not rely on a single Widal test to diagnose and treat typhoid, many, like the hospital I went to, still do. The Nigerian Standard Treatment Guideline as regards the treatment of typhoid needs to be enforced in every treatment and diagnostic centre in Nigeria.

The danger of an incorrect typhoid diagnosis is that the symptoms of typhoid fever are difficult to distinguish from other viral haemorrhagic fevers like Lassa fever, malaria or yellow fever. Health professionals are advised to maintain a high index of suspicion for infectious diseases like Lassa fever, especially when a patient presents with a high temperature, muscle pain, vomiting or diarrhea, similar symptoms as typhoid fever.

Shortages of health professionals in many primary health centres in Nigeria and the absence of diagnostic facilities and laboratory scientists makes it harder for health professionals to correctly diagnose typhoid, resulting in the reliance on the Widal test. State governments need to provide the necessary equipment in at least each Local Government Area (LGA) in every state, so more hospitals and health centres are able to diagnose typhoid and other infectious diseases. To stop the widespread misdiagnoses of typhoid fever, continuous and vigorous continuous training of health workers needs to take place in every state and LGA. Professional associations should also play a larger role in ensuring all health professionals take part in continuous professional development training to ensure they continue to enhance their skills so as to deliver quality healthcare.

I am glad that after close to two years of being misdiagnosed and treated for typhoid fever using only a Widal test, I now have the knowledge to understand that the next time my doctor wants to diagnose me using only a Widal test, I can insist that a blood, stool, and urine culture be done. Many others need to have this knowledge, we all want to have access to quality healthcare, we also want to have confidence that our illnesses are being correctly diagnosed.

Have you ever been diagnosed with typhoid only with a widal test? Share your story with us

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