RTI-Cassandra™: Disease Outbreak Simulation Tool

RTI Cassandra is a sophisticated individual-based model (IBM) developed by RTI International in response to the increased number of infectious disease outbreaks around the world. It is used to simulate the spread of established, novel, emerging, and re-emerging infectious disease agents, including viruses, bacteria, and protozoa, among humans. RTI Cassandra‘s modelling framework is highly scalable, with the ability to simulate pathogen spread at a national level.

RTI Cassandra can be used to identify potential infectious disease hotspots, predict epidemic trajectories, and provide useful insights to strategize interventions aimed to protect vulnerable groups and health workers. The epidemiological model can also be used to assess the performance of non-pharmacological interventions (NPIs), such as masks and distancing, as well as vaccination campaigns deployed in response to a disease outbreak.

RTI Cassandra has been employed to evaluate preventive vaccination efforts against Zaire Ebola in the Democratic Republic of Congo (and assess NPIs during the 2022 Sudan Ebola outbreak in Uganda. It also supported decision-making for COVID-19 NPIs and vaccination in Saudi Arabia from 2020-2023 and simulated the spread of mpox in high-income Western countries.

How does RTI Cassandra’s infectious disease modelling work?

RTI Cassandra simulates the spread of infectious agents across synthetic populations. It accounts for variations in human interactions, including the number and duration of contacts, and has a disease transmission modeling feature that simulates how diseases are transmitted within a population. Designed to provide rapid support during outbreak periods, RTI Cassandra provides results within a week. The model is conceptualized as “rule-based” with a very low level of complex mathematical formulas that make it easier to understand by non-experts, compared to the classical formula-heavy models.

RTI Cassandra‘s modeling framework accounts for important factors beyond those in previously published IBMs. It merges human mobility and environmental characteristics that are essential for understanding how diseases spread geographically, including the distribution of the target population, human movement, heterogeneity of human contact with country-specific demographic characteristics, interactions within households and in the community, interaction among age groups, and the structure of the health system workforce. The model also accounts for environmental factors that are the main drivers of many disease outbreaks, such as forest coverage, elevation, temperature, and rainfall.

RTI Cassandra is designed to complement national disaster preparedness and management policies; public health emergency operations; and the activities of relevant task forces and intra-government agencies, external partners, and infrastructure and resources built in response to infectious disease threats.