Estimating the Seroincidence of Melioidosis, Typhoid Fever and Scrub Typhus from Cross-sectional Serosurveys

SUMMARY/ABSTRACT
This mentored International Research Scientist Development Award (K01) from UC Davis and Mahidol
University-Thailand will support Dr. Kristen Aiemjoy, Assistant Professor of Epidemiology, to establish an
impactful, independent global health research program developing seroepidemiologic tools to measure and
reduce the burden on infectious diseases globally. In Thailand, a priority research need is scalable tools to
understand the population-level burden for etiologies of acute fever, with acute undifferentiated fever being the
second-leading cause of care-seeking nationwide. To meet this need, the scope of this K01 is to evaluate
innovative and pragmatic seroepidemiologic tools to characterize the population-level burden of three etiologies
of acute undifferentiated fever: scrub typhus, melioidosis, and typhoid fever. The Specific Aims are Aim 1A) To
model longitudinal antibody responses for scrub typhus and melioidosis and estimate peak antibody response,
decay rate, and decay shape, and Aim 1B) To determine if antibody responses vary according to age; Aim 2)
To develop an analytic approach for estimating the seroincidence of scrub typhus, melioidosis and typhoid fever
from cross-sectional survey data; and Aim 3) To quantify the magnitude of selection bias induced by a school-
based sample relative to a random population-based sample when estimating the incidence of scrub typhus,
melioidosis, and typhoid fever. Data sources for the research strategy include existing longitudinal data from
confirmed melioidosis, scrub typhus, and typhoid fever cases; high-dimensional simulated data; and prospective
population-level serosurveys in Nong Khai province in Northeast Thailand. The research aims are paired with
training goals designed to provide Dr. Aiemjoy with the skills and experiences necessary to build an independent
global health research program. The specific training goals are to 1) acquire technical proficiency in the
fundamental immunology of scrub typhus, enteric fever, melioidosis infections relevant for seroepidemiology; 2)
establish expertise in innovative analytic approaches and computation tools for serologic data; and 3) cultivate
the leadership, professional skills, and research partnerships necessary to become an independent global health
research scientist. The training plan will be guided by a team of experienced mentors led by Dr. Narisara
Chantratita (primary co-mentor, Mahidol University), a globally recognized leader in melioidosis immunology with
over 30 years of clinical and laboratory infectious disease research in Thailand. Dr. Jason Andrews (primary co-
mentor, Stanford University), a clinical scientist with expertise in statistical inference and mathematical modeling,
will provide mentorship to evaluate diagnostics and interventions for tropical infectious diseases. The prolonged
field experience and collaborative research supported by this IRSDA-K01, coupled with strong institutional
support from UC Davis (Dr. Pollock, UCD Chair of Public Health Sciences and professional development
mentor), will cultivate a sustained international research partnership with Dr. Aiemjoy and Mahidol University
aimed at reducing the burden of infectious disease in Thailand and Globally.

Grant Number: 5K01TW012177-04
NIH Institute/Center: NIH
Principal Investigator: Kristen Aiemjoy