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SEAP: Surveillance for Enteric Fever in Asia Project

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Chris LeBoa with SEAP Team member
Chris LeBoa with SEAP Team member

“How can typhoid fever be prevented? ... the reply to the above question may be stated in four words, namely, Stop drinking contaminated water.” – Henry Baker, 1884

Surveillance for Enteric Fever in Asia Project (SEAP)



To characterize the burden of enteric fever in south Asia using:

      1.  Retrospective review of laboratory and hospital records for blood-culture confirmed cases of Salmonella Typhi and S. Paratyphi from Bangladesh, India, Nepal, and Pakistan


      2.  Prospective surveillance in Bangladesh, Nepal, and Pakistan to examine:

           a.  Population-based adjusted incidence of enteric fever infections, risk factors, clinical complications, and long-term impact including fatality using a hybrid hospital- and community-based approach

           b.  Patterns of antimicrobial resistance for S. Typhi and Paratyphi

           c.  Serologic markers of typhoid infection

           d.  Environmental water contamination with S. Typhi and S. Paratyphi A



Why we care about this

Enteric fever is a common collective term for two similarly transmitted Salmonella infections: typhoid and paratyphoid fevers caused by Salmonella Typhi and Salmonella Paratyphi A, B, or C. Respectively, typhoid and paratyphoid fever have been estimated to cause about 26 million and 5 million illnesses with 190,000 enteric fever deaths each year globally. Enteric fever remains a major public health problem in low income countries, particularly in Asia and sub-Saharan Africa, where a large proportion of the population lacks access to safe water, sanitation, and hygiene infrastructure. Diagnosis and treatment of enteric fever is difficult due to non-specific symptoms of febrile illness, the gold standard diagnostic of bacterial culture being only 40-60% sensitive, and rising rates of antibiotic resistance. Measuring incidence, complications, and deaths due to typhoid is also difficult due to lack of universally accepted case definitions, low-yield diagnostics, and limited prior studies. There have been efforts to estimate population-based incidence of enteric fever, but data on enteric fever associated severity and hospitalization rate, long term complications, and mortality are minimal. The absence of credible estimates of the burden of enteric fever have discounted the impact of the disease and thus have reduced the political support needed for prevention and control efforts.

Why we see the knowledge we are generating as strategic:

We are using retrospective review of confirmed typhoid and paratyphoid cases as well as prospective surveillance using a hybrid hospital- and community-based approach to characterize enteric fever burden in south Asia. This study will generate data that can be used for prevention and control action at the local level, as well as provide estimates for national, regional, and global level policies. Ultimately, results from this project will be instrumental in paving the way for typhoid fever conjugate vaccine use, development of next-generation enteric fever vaccines, and other typhoid prevention and control efforts.


Project Dates



Stage of Work

Stages on Stairway of Research - Stages 1 and 2: 

Stage 1:  Identify a problem

Stage 2:  Explicate the causal paths that generate the problem


What has been accomplished so far within the project

Retrospective review of typhoid cases published:

Phase I of the surveillance for enteric fever in Asia Project (SEAP): an overview and lessons learned (The Journal of Infectious Diseases | December 1, 2018)

What we are focusing on now

Prospective hospital, laboratory, community, and environmental surveillance data collection is ongoing.



Primary Contact:  Jason Andrews

Stanford University

.  Stephen Luby, Senior Advisor

.  Jason Andrews, Assistant Professor, Co-I and PI for Nepal site

.  Kristen Aiemjoy, Postdoctoral research fellow, Co-I

Sabin Vaccine Institute

.  Denise Garrett, PI

Centers for Disease Control and Prevention (CDC)

.  Kashmira Date, Co-PI

Child Health Research Foundation, Dhaka, Bangladesh

.  Samir Saha, Co-I and PI for Bangladesh site

Aga Khan University, Karachi, Pakistan

.  Farah Qamar, Co-I and PI for Pakistan site



Bill and Melinda Gates Foundation