An Analysis of Compounding Factors of Epidemics in Complex Emergencies: A System Dynamics Approach

Purpose: This research describes compounding factors in a complex emergency
which exacerbate a cholera epidemic among vulnerable populations due to supply
chain disruptions. Basic needs such as food, medicine, water, sanitation, and
hygiene commodities, are critical to reduce the incidence rate of cholera and
control the spread of infection. Conflicts cause damage to infrastructure, displace
vulnerable populations, and restrict the flow of goods from both commercial and
humanitarian organizations. This work assesses the underlying internal and
external factors which either aggravate or mitigate the risk of a cholera outbreak
in such settings, using Yemen as a case study.
Design/Methodology/Approach: This study adopts a system dynamics
methodology to analyze factors which influence cholera outbreaks in the context
of the Yemeni Civil War. A causal loop diagram with multiple components was
constructed to represent the complexities of humanitarian situations which
require critical decision-making. The model was built using data from
humanitarian organizations, NGOs, and practitioners, along with literature from
academic sources. Variables in the model were confirmed through semistructured interviews with a field expert.
Findings: Compounding factors which influenced the cholera outbreak in
Yemen are visualized in a causal loop diagram, which can improve understanding
of relationships where numerous uncertainties exist. A strong link exists between
humanitarian response and the level of infrastructure development in country.
Supply chains are affected by constraints deriving from the Yemeni conflict,
further inhibiting the use of infrastructure, which limits access to basic goods and
services. Aligning long-term development objectives with short-term
humanitarian response efforts can create more flexible modes of assistance to
prevent and control future outbreaks.
Research limitations/implications: The model focuses on the qualitative
aspects of system dynamics to visualize the logistics and supply chain-related
constraints that impact cholera prevention, treatment, and control through
humanitarian interventions. The resulting causal loop diagram is bounded by the
Yemen context, thus an extension of the model adapted for other contexts is
recommended for further study.
Practical implications: This research presents a systematic view of dynamic
factors existing in complex emergencies which have cause and effect
relationships. Several models of cholera outbreaks have been used in previous
studies, primarily focusing on the modes and mechanisms of transmission
throughout a population. However, such models typically do not include other
internal and external factors which influence the population and context at the
site of an outbreak. This model incorporates those factors from a logistics
perspective to address the distribution of in-kind goods and cash and voucher
assistance.
Social implications: This research has been aligned with six of the United
Nations Sustainable Development Goals, using their associated targets in the
model as variables which influence the cholera incidence rate. Recognizing that
the SDGs are interlinked, as are the dynamic factors in complex humanitarian
emergencies, we have chosen to take an interdisciplinary approach to consider
social, economic, and environmental factors which may be impacted by this
research.
Originality/Value: This paper provides an insight into the underlying
interrelations of internal and external factors present in the context of a cholera
outbreak in a complex emergency. Supply chains for food, WASH, and health
commodities are crucial to help prevent, control, and treat an outbreak. The model
exposes vulnerabilities in the supply chain which may offer guidance for decision
makers to improve resilience, reduce disruptions, and decrease the severity of
cholera outbreaks.
Keywords: Humanitarian logistics, complex emergency, cash and voucher
assistance, epidemics, in-kind assistance, system dynamics, resilience, cholera
outbreak, disruptions, casual loop diagram