ABSTRACT
Background & objectives: Although febrile illnesses are a frequent cause of consultation and hospitalization in low- and middle-income countries (LMICs), research has mainly focused on acute febrile illnesses (AFIs). In contrast, there are limited data on the causes of persistent febrile illnesses (PFIs) in LMIC. Lack of clarity on the differential diagnosis of PFIs in the rural tropics leads to the absence of diagnostic guidance tools. Methods: In this study, a review of the potential causes of persistent fever defined as fever of more than seven days was done in Nepal, with a focus on nine pathogen-specific conditions. The current knowledge on their burden, distribution and diagnosis was summarized. Results: Limited data were found on the incidence and public health burden of leptospirosis, murine typhus and brucellosis due to the absence of diagnostic tools outside reference laboratories and the overlap of signs and symptoms with other febrile conditions. The incidence of malaria and visceral leishmaniasis (VL) was found to be decreasing in Nepal, with some changes of the geographical areas at risk. Interpretation & conclusions: This review indicates a need for more research on the causes of PFIs in Nepal and in the region and for the development of clinical guidance tailored to current local epidemiology. Guidance tools should include specific clinical features (e.g. eschar), results of rapid diagnostic tests (e.g. malaria, VL), appropriate indications for more sophisticated tests (e.g. abdominal ultrasound, polymerase chain reaction) and recommendations for adequate use of empirical treatment.
ABSTRACT
Scrub typhus is a potentially fatal, febrile disease prevalent in rural Asia. The etiological agent, Orientia tsutsugamushi, is transmitted to humans by the bite of a larval trombiculid mite. No current diagnostic test is sufficiently practical for use by physicians working in rural areas. A new dipstick test using a dot blot immunoassay format has been developed for the serodiagnosis of scrub typhus. We evaluated this test on 83 patients presenting with acute fever of unknown origin at Maharaj Hospital, a tertiary care medical center in Nakhon Ratchasima, Northeast Thailand. The diagnosis of scrub typhus was confirmed in 30 of these patients (36%) by the indirect immunoperoxidase test. The sensitivity of the test was 87% and its specificity was 94%. The dot blot immunoassay dipstick is accurate, rapid, easy to use, and relatively inexpensive. It appears to be the best currently available test for diagnosing scrub typhus in rural areas where this disease predominates.