Molecular technique utilising sputum for detecting Wuchereria bancrofti infections in Malindi, Kenya

Background: Lymphatic filariasis is a tropical parasitic disease which has been identified for elimination by 2020 through mass drugs administration. There is a major problem in its diagnosis and sensitive surveillance methods for monitoring the disease elimination programs need to be sought. Objectives: To establish and evaluate the usefulness of a Polymerase Chain Reaction, PCR assay employing sputum for diagnosis of Wuchereria bancrofti infections in an endemic location. Design: Community based samples collection and a molecular laboratory technologies study. Setting: Mpirani, Malindi District and Centre for Biotechnology Research and Development, Kenya Medical Research Institute. Subjects: Sputum samples were obtained from 304 willing and consenting participants, aged between 5 and 73 years resident in Mpirani, Malindi District. Results: Prevalence of W. bancrofti infection was found to be 42.8% (130/304) by PCR assay employing sputum compared with 22.0 % (67/304) and 38.8% (119/304) respectively for microfilaria counts and ICT. The sensitivity and specificity of the PCR sputum assay was 97.5 and 92.4% respectively. Predictive values were 89.2 and 98.3% for positive (PPV) and negative (NPV) respectively while accuracy was 94.4%. Conclusions: The molecular PCR assay using sputum was found to have a great potential for use in mass diagnosis and in epidemiological studies in patients with W. bancrofti infections.