Effect of Healthcare on Ebola Prevention
The World Health Organization (WHO) is currently combatting a recent Ebola outbreak in the Democratic Republic of Congo which began on November 20, 2019. Researchers are tracking the spread of disease while health workers are implementing measures to prevent the spread of disease. While this outbreak only affects zones in a few regions in Africa, it is important for researchers to consider several questions such as: Will this disease will ever completely die out? Is it more effective to reduce p, the transmission probability, or k, the number of contacts, to reduce the spread of disease as much as possible? At which state (susceptible, infectious, removed) should the disease be treated?
In a basic model to represent the spread of disease, nodes represent people and edges represent contacts, or connections for possible transmissions. In order to track the branching process and determine whether a disease will ever die out, researchers must determine values for p and k and apply the Galton-Watson process. If k is 0, we know that the disease will definitely die out. If k is greater than 0 but p is 1, the disease will continue to be spread because there is a 100% probability that it will be passed on. However, if k is greater than 0 but p is less than 1, there is a possibility that the disease will die out. This is because if k is 1 and p is less than 1, the disease will surely die out. In the case of the Ebola epidemic in Africa, k is certainly greater than 0 as there are many people infected with the disease, however, p is unknown. Determining whether p is 1, meaning that the disease will certainly be passed on, or if p is less than 1 is crucial for researchers to decide how to best prevent the spread of the disease.
Healthcare officials in Africa are attempting to reduce Ro, the expected number of transmissions by one node, in order to prevent the spread of Ebola. They are doing this in two ways: reducing the transmission probability and reducing the number of people in contact with the disease. In order to reduce the transmission probability, healthcare workers are taking surveillance and control measures such as case finding, contract tracing and vaccination. These measures are preventive, treating people at the susceptible state rather than the infected state. However, because of recent disruptions such as violence, civil unrest, targeted attacks, recent progress has been reversed, increasing infection rates. In order to reduce the number of contacts with the disease, WHO advises against restriction of travel to and trade with the Democratic Republic of Congo. By using mathematical models, researchers can determine if they should focus their efforts on reducing the transmission probability or the number of contacts with the disease to reduce Ro overall.
With the current research available to the public, we cannot provide perfect solutions to the questions posed above. However, understanding the logic behind the branching process and spread of the disease is essential to best treating and preventing the spread of the disease. Hopefully researchers will take this into consideration while finding solutions to improve access to healthcare.
https://reliefweb.int/sites/reliefweb.int/files/resources/WHO_16.pdf