12 Jun Mathematical Model Investigates Spread of Cholera In Limited Resource Setting

Posted at 20:19h in Author Interviews, Global Health, Infections by

MedicalResearch.com Interview with:
“Cholera Hospital 3” by Mark Knobil is licensed under CC BY 2.0Dr. Daihai He
Assistant Professor
Department of Applied Mathematics
Hong Kong Polytechnic University  

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: A large-scale cholera outbreak hit Yemen in 2017-2018 and caused an estimated 1,100,720 suspected cases and 2291 associated deaths between 27 April 2017 and 20 May 2018, thus a case fatality ratio 0.21%.

MedicalResearch.com: What should readers take away from your report?

Response: What is the infection attack rate (IAR) of this outbreak? The infection attack rate is the proportion of the whole population infected during the outbreak. The population of Yemen is about 27 million in 2016. The actual susceptible population is smaller, e.g. “eighty per cent of Yemen’s population in need of aid –UN” according to BBC news Apr 2016, Guardian.com July 2017. “Collapsing health, water and sanitation systems have cut off 14.5 million people from regular access to clean water and sanitation, increasing the ability of the disease to spread.” (https://en.wikipedia.org/wiki/2016%E2%80%9318_Yemen_cholera_outbreak). Shall we assume that the 1,100,720 susceptible cases represent all infections? If yes, then the IAR could be less than 5%. A small IAR implies following cholera outbreak in the summer of 2018 is possible. However, “WHO estimates that the officially reported cases represent only 5–10% of the actual number occurring annually worldwide.” If we assume that the 1 million reported cases only represent 10% (or 25% or 50%) of the actual infected cases, thus the IAR would be 50% (or 20% or 10%). Higher IAR could prevent an immediate cholera wave.

In this work, we presumed a reporting ratio of 25% and found that the model can successfully capture the two epidemic waves. To our knowledge, this is the first modelling effort of its kind. Our results imply a high IAR (e.g. 25%), thus an immediate epidemic wave in 2018 is unlikely. Furthermore, we incorporate the impact of medical resource in our model and find the heterogeneous patterns of the disease prevalence and severity across the country. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: Whether an immediate epidemic wave will occur or not is dependent on the assumption of the reporting ratio of cholera cases and the protection level of infection-induced immunity. 

Citation:

Modeling the 2016–2017 Yemen cholera outbreak with the impact of limited medical resources
https://www.sciencedirect.com/science/article/pii/S002251931830225X
Daihai He, Xueying Wang, Daozhou Gao, and Jin Wang

https://doi.org/10.1016/j.jtbi.2018.04.041
Journal of Theoretical Biology 451:80-85

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Last Updated on June 12, 2018 by Marie Benz MD FAAD

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