Scrub Typhus RDT Study

Overview

Fever is one of most common presenting complaints in clinics in tropical countries. Rickettsial infections, enteric fever and leptospirosis are common and important causes of undifferentiated fever in Southeast Asia. Scrub typhus is caused by Orientia tsutsugamushi and humans are typically infected by a bite of an infected chigger (trombiculid mite larva). Clinical diagnosis is unreliable for identifying scrub typhus, unless a tick eschar is present which is almost pathognomonic for the disease in Southeast Asia. A combination of culture, paired serology and PCR has been proposed as the gold-standard method for detection. As a result laboratory confirmation is not widely available and the diagnosis is missed frequently in clinical practice. Some progress has been made in developing such a test and one promising candidate is the Scrub Typhus Detect IgM Rapid Test (InBios International Inc). We plan to use to this test in this study to estimate the prevalence of scrub typhus in selected febrile patients presenting to clinics in Myanmar . Patients will be followed up for one week to check for resolution of symptoms.

Title: A multicenter observational study to describe the prevalence of scrub typhus defined as s positive rapid diagnostic test among selected patients presenting with fever to clinics in Myanmar. Rational and objectives of the study Fever is one of most common presenting complaints in clinics in tropical countries. Rickettsial infections, enteric fever and leptospirosis are common and important causes of undifferentiated fever in Southeast Asia. The largest and earliest reports of scrub typhus in Myanmar were made during World War II when this disease afflicted numerous troops, particularly those serving close to the border with India. Scrub typhus is caused by Orientia tsutsugamushi and humans are typically infected by a bite of an infected chigger (trombiculid mite larva). Clinical diagnosis is unreliable for identifying scrub typhus, unless a tick eschar is present which is almost pathognomonic for the disease in Southeast Asia. A combination of culture, paired serology and PCR has been proposed as the gold-standard method for detection. As a result laboratory confirmation is not widely available and the diagnosis is missed frequently in clinical practice. Some progress has been made in developing such a test and one promising candidate is the Scrub Typhus Detect IgM Rapid Test (InBios International Inc). In laboratory-based evaluations using stored sera collected from patients recruited in a study in Thailand with confirmed scrub typhus this test had a sensitivity of \~80% for the detection of the disease compared to serological methods. We plan to use to this test in this study to estimate the prevalence of scrub typhus in selected febrile patients presenting to clinics in Myanmar. Primary objective: To describe the prevalence of scrub typhus defined as a positive rapid diagnostic test among selected patients presenting with fever to clinics in Myanmar Secondary objective: * To assess inter-observer agreement when interpreting the tests * To assess the ease-of-use of the tests * To direct future research efforts into rickettsial disease in Myanmar * To raise awareness of the presence of scrub typhus in Myanmar Inclusion criteria 1. Male or female \>1 year of age 2. Fever defined as \> 38 °C tympanic temperature 3. Duration of fever \>48h 4. Written informed consent (by legally acceptable representative in case of children), and assent for children age 10-17 year 5. Eschar (60 patients only) Exclusion criteria * Malaria confirmed by RTD or microscopy * Skin/soft tissue infection, dysentery or urinary tract infection probable cause of fever Procedures and Methodology The study will be carried out to describe the prevalence of scrub typhus defined as a positive rapid diagnostic test among patients presenting with fever to six participating clinics in Myanmar. Patients coming with fever to participating clinics will be routinely assessment by attending physician. Patients meeting the inclusion and exclusion criteria for the study will be invited and enrolled to the study after getting informed consent. Rapid diagnostic test and laboratory procedure A scrub typhus rapid test will be performed on site by using the InBios Scrub Typhus Detect IgM Rapid Test. Tests will be read by two independent readers and results recorded as positive, negative or invalid. In case of invalid test result, another test will be performed using a new test strip. If there is any disagreement between two readers, the lead investigator at the site will decide the test result and the test will be photographed. In patients with a skin eschar a sterile surgical blade will be used to gently scrape the surface of the eschar. Scrapings will be stored in a cryotube containing 95% ethanol and stored at -80°C for future analysis (PCR genotyping ± whole genome sequencing) to confirm the presence of Orientia tsutsugamushi. Treatment Physicians will be advised to formulate a treatment plan according to their usual practice but it will be recommended that treatment for scrub typhus be added to the regimen if the test is positive i.e. doxycycline 100mg bd for seven days in adults or 4mg/kg day in two divided doses in children older than eight years. Doxycycline is contraindicated in pregnant women and children eight years old or below and these groups should be prescribed azithromycin (500mg single dose). Follow up Patients will be reassessed at one week to check for resolution of fever and symptoms . Any patient with ongoing symptoms will be re-assessed by a physician. Duration and Study Sites Patients will be recruited 1 year starting from December 2017 to November 2018 in six sites: Yae township hospital, No.2, 1000 Bedded Military Hospital (Nay Pyi Taw), No.20, 100 Bedded Military Hospital (Tha Beik Kyin), NAP-MAM clinics (Kawkareik and Putao township), No.2, 300 Bedded Military Hospital (Ann, Rakhine State). Risk and benefits This is a low risk study. Finger prick for RDT and scrapping from eschar (for patients who have eschar) may cause slight discomfort. Some patients may receive antibiotics they would not have otherwise been prescribed as a result of having the test. However this is most likely to benefit them as these tests have been shown to be sensitive and specific for the diagnosis of scrub typhus in similar settings. Incentives and Compensation There will be no incentives or compensation for study participation. Confidentiality The study will ensure that the participants' anonymity is maintained. The participants will be identified only by initials and a study number on the CRF and the study database. Publication The research findings will be disseminated to policy-makers and other interested parties inside Myanmar. If there are any publications resulting from the results all those who have made a substantial contribution will be co-authors.