Specificity of Widal test in healthy blood donors and patients with meningitis

Abstract

The Widal agglutination test detects serum antibodies against the O and H antigens of Salmonella typhi, and Salmonella paratyphi A, B, or C. Clinicians in Africa commonly use the Widal test diagnose typhoid fever despite well recognised false positive and false negative results. In Malawi, patients presenting urban hospitals or private clinics with fever and headache who do not have malaria or who have not responded anti-malarial chemotherapy often have a Widal test; a positive test usually leads a diagnosis of typhoid fever and treatment with chloramphenicol for 2 weeks. Healthy persons who apply for work in kitchens or restaurants may also be requested by their prospective employers have a Widal test to rule out typhoid fever; a positive result precludes the individual from such work, and often leads treatment with chloramphenicol for 2 weeks. An important cause of fever and headache is meningitis. Chronic meningitis, presenting with fever, headache and confusion, and often due infection with Cryptocoecus neoformans or Mycobacterium tuberculosis, may be particularly difficult distinguish clinically from typhoid fever. There is little information in Malawi about the specificity of Widal testing in healthy persons or in people with meningitis. Thus we carried out a prospective study investigate this.