Can clinical features predict Lassa virus positivity and outcome in children suspected of Lassa virus disease in a tertiary hospital, Southeast Nigeria?

Background: Lassa virus disease (LVD) is of public health concern in endemic countries of Africa. Majority of Lassa virus infections are asymptomatic while symptomatic cases can mimic other infections. This study was aimed at determining the clinical features seen in children with positive Lassa virus PCR and symptoms that determine outcome of LVD in an endemic community, Southeast Nigeria. Materials and methods: It was a prospective observational study that enrolled 183 children that met the criteria for LVD suspects. These were subjected to the Lassa virus polymerase chain reaction test (PCR). Structured questionnaire was used to obtain relevant information from suspects. Results: Twenty-four out of the 183 were positive to Lassa virus PCR, giving a positivity rate of 13.1%. The odds of having a positive Lassa PCR result was about 4 times in children with history of abdominal pain (OR= 3.65, p= 0.010) and about 3 times in Lassa fever suspects with vomiting (OR= 2.63, p= 0.040). However these symptoms had low sensitivity and positive predictive values of 42% and 28% for abdominal pain, and 42%, 23% for vomiting respectively. Seven out of 24 children died during the study period, giving a case fatality rate of 29.2%, with bleeding (83.3%) and poor urine volume (83.3%) as major causes of case fatality. Conclusion: Vomiting and abdominal pain though were common presentations besides fever, had low sensitivity and positive predictive values for LVD, therefore cannot predict a positive Lassa PCR result. Awareness creation for a Lassa virus PCR test after 2 days of treatment of febrile illness is advocated.