Seroprevalence and Clinical Profile of Scrub Typhus in Children in a Rural Tertiary Care Hospital, Tamilnadu, India

Abstract

Introduction: Rickettsial disease in children has shown an increasing trend in several parts of India over recent years. The clinical features and seroprevalence vary in different geographic areas. Aim: To determine the seroprevalence and clinical features of Scrub typhus in paediatric patients. Materials and Methods: The prospective study was conducted for a period of six months included all paediatric patients <12 years of age with suspected scrub typhus infection. Serodiagnosis was done by performing Weil Felix (WF) on all serum samples. Clinical examination findings and other investigations were recorded from the medical case records. Statistical analysis of data was performed with Microsoft Excel. The significance of demographic and clinical features was determined by calculation of p-value by Fisher-exact test using Statistical Package for the Social Sciences (SPSS) software version 17.0. Results: Among 152 children satisfying the inclusion criteria, 60(39.5%) had a titer ≥1:80 with OXK antigens in WF test and 92 children (60.5%) had a titre less than 1:80. Scrub typhus IgM Enzyme-linked immunosorbent assay (ELISA) was positive in 69 children (45.4%) and the rest were negative {n=83(54.6%)} The sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and accuracy of WF as compared to the Scrub typhus IgM ELISA were 71.01%, 86.75%, 81.67%, 78.26% and 79.61%, respectively. The commonest age group of children with scrub typhus was 1-4 years {n=30 (43.5%)}. Fifty three children (76.8%) presented with high grade and intermittent fever. The commonest clinical signs were hepatomegaly {n=51(73.9%)} splenomegaly {n=37(53.6 %)} and eschar {n=21(30.4%)}. The most common laboratory findings were anaemia {n=44(63.8%)} and thrombocytopenia {n=21 (30.4%)}. Conclusion: The seroprevalence of Scrub typhus in paediatric population was 45.4% (n=69). The eschar was present in 30% of the study group (n=21) and the most common clinical presentation was high grade intermittent fever with hepatosplenomegaly which are seen in other tropical infections as well. The laboratory plays a pivotal role with serodiagnosis by IgM ELISA, a necessity in confirming the diagnosis.

Keywords

• 56 kda antigen
• orientia tsutsugamushi
• paediatric population
• rickettsial disease
• weil-felix test