Arthropod Borne Disease: The Leading Cause of Fever in Pregnancy on the Thai-Burmese Border

Rose Mcgready,Daniel H Paris,Nicholas J White,Nicholas P Day,Mupawjay Pimanpanarak,Stuart D Blacksell,François Nosten,Vanaporn Wuthiekanun,Pratap Singhasivanon,Wilarat Jesadapanpong,Sharon J Peacock,Samuel Jacher Viladpai-Nguen,Saw Oo Tan,Elizabeth A Ashley,Joseph M Vinetz

doi:10.1371/journal.pntd.0000888

Abstract

BackgroundFever in pregnancy is dangerous for both mother and foetus. In the 1980's malaria was the leading cause of death in pregnant women in refugee camps on the Thai-Burmese border. Artemisinin combination therapy has significantly reduced the incidence of malaria in the population. The remaining causes of fever in pregnancy are not well documented.MethodologyPregnant women attending antenatal care, where weekly screening for malaria is routine, were invited to have a comprehensive clinical and laboratory screen if they had fever. Women were admitted to hospital, treated and followed up weekly until delivery. A convalescent serum was collected on day 21. Delivery outcomes were recorded.Principal FindingsFebrile episodes (n = 438) occurred in 5.0% (409/8,117) of pregnant women attending antenatal clinics from 7-Jan-2004 to 17-May-2006. The main cause was malaria in 55.5% (227/409). A cohort of 203 (49.6% of 409) women had detailed fever investigations and follow up. Arthropod-borne (malaria, rickettsial infections, and dengue) and zoonotic disease (leptospirosis) accounted for nearly half of all febrile illnesses, 47.3% (96/203). Coinfection was observed in 3.9% (8/203) of women, mostly malaria and rickettsia. Pyelonephritis, 19.7% (40/203), was also a common cause of fever. Once malaria, pyelonephritis and acute respiratory illness are excluded by microscopy and/or clinical findings, one-third of the remaining febrile infections will be caused by rickettsia or leptospirosis. Scrub and murine typhus were associated with poor pregnancy outcomes including stillbirth and low birth weight. One woman died (no positive laboratory tests).Conclusion/SignificanceMalaria remains the leading cause of fever in pregnancy on the Thai-Burmese border. Scrub and murine typhus were also important causes of fever associated with poor pregnancy outcomes. Febrile pregnant women on the Thai-Burmese border who do not have malaria, pyelonephritis or respiratory tract infection should be treated with azithromycin, effective for typhus and leptospirosis.

Highlights

Febrile illness in pregnancy increases the risk of maternal death and infant morbidity and mortality
This study examined the causes of fever in pregnant women using laboratory support that is typically unavailable to most women living in the tropics
On the Thai-Burmese border there has been a great reduction in malaria in the last 20 years

Summary

Introduction

Febrile illness in pregnancy increases the risk of maternal death and infant morbidity and mortality. In a prospective study of pregnant women and their infants (n = 1,495) on the ThaiBurmese border, maternal febrile illness of any cause was associated with a 2.5 (95%CI 1.3–5.0) fold increased risk of neonatal death [4]. A better understanding of the causes of febrile illness in pregnant women in rural tropical areas could reduce maternal and neonatal morbidity and mortality. This pilot survey aimed to identify the organisms responsible for fever in pregnant women on the North-Western Thai-Burmese border. The remaining causes of fever in pregnancy are not well documented

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Conclusion