Observing the effectiveness of safe burial practices for reducing the spread of the Ebola virus using mathematical modelling techniques

Task:

Choose an infectious disease and develop a model to capture the transmission dynamics of the disease. Then choose a control mechanism used to curb the spread of the disease and investigate its impact. Present the investigation in a ten-page report, along with a one-page policy brief to present to health policy maker.

Introduction:

The Ebola virus is a rare but severe haemorrhagic fever virus that is often fatal in humans if left untreated. With occasional outbreaks occurring primarily on the African continent, the largest Ebola virus disease outbreak to date occurred in West Africa, more specifically in parts of Guinea, Sierra Leone and Liberia between 2014 and 2016 since the virus was first discovered in 1976. A total of 28 616 cases of the virus and 11 310 deaths were recorded. There were a further 36 cases and 15 deaths which occurred outside of these three countries (Liu and Stechlinski, 2011).

The Ebola virus is known to commonly affect humans, non-human primates and bats. There are six known virus species within the genus Ebola, namely the Zaire ebolavirus, Sudan ebolavirus, Tai Forest/Cote d’Ivoire ebolavirus, Bundibugyo ebolavirus, Reston ebolavirus and Bombola ebolavirus species. Of these species, only the first four are known to cause disease in humans. Reston ebolavirus is known to only cause disease in non-human primates and pigs. In the case of the Bombali ebolavirus, which is prevalent in the bat species, there is no evidence to suggest that it affects humans or any other animal (Centers for Disease Control and Prevention, 2019).

The Ebola virus can be transmitted via direct contact with blood, bodily fluids or the skin of Ebola virus disease patients or individuals who have died of the disease. It is known to cause problems with how the blood clots in the body. This often leading to internal bleeding, as blood leaks from small blood vessels in the body. The virus further causes inflammation and tissue damage (Garibaldi, n.d).

Despite efforts, knowledge of the natural reservoir of the virus remains unknown. Not very much is understood regarding how the Ebola virus is transmitted or how it is able to replicate itself in a host. However, based on research that has been performed on similar viruses, there is evidence to suggest that the virus is zoonotic, and can therefore be maintained by an unidentified animal host. With Ebola virus outbreaks generally coinciding with the end of a rainy season, there is evidence to suggest that the natural ecology of the virus and the host may be influenced by the weather cycle (Liu and Stechlinski, 2011).

The foundation for controlling an outbreak of the Ebola virus is to interrupt the viral transmission chain. This requires several strict public health measures to be implemented as swiftly as possible. These measures include the isolation of patients, barrier precautions, and identification and tracking of all contacts. These measures are extended to encouraging the avoidance of contact with blood and bodily fluids of persons who are infected, as well as objects and surfaces which may be contaminated with an infected person’s blood or bodily fluid on a national scale. Avoiding contact with semen from a man who has recovered from the Ebola virus disease, until testing verifies that the virus has left the semen. Employing teams to handle the body of an infected person who has died. And lastly, avoiding contact and consumption of bats and non-human primates which have not been handled and prepared thoroughly (Liu and Stechlinski, 2011).

As mentioned earlier, the handling of bodies of infected patients who have died without necessary protection is considered a biosafety hazard. Therefore, conventional burial practices in the African continent leave many uninfected family and community members in attendance vulnerable to contracting the virus. The burial process is often a very sensitive matter for both the family and community: any drastic changes to how these communities are permitted to conduct such processes can be the source of community resistance or even conflict against measures to reduce the rate of transmission during an epidemic. As a result, any burial procedure which seeks to handle the bodies of the deceased in a way that mitigates further transmission of the virus needs to be preceded by a consultation with the family of infected persons so that the procedure is still dignified and honours their religious and personal rights to show respect for the deceased (World Health Organization, 2020).

With no cure or specific treatment for the Ebola virus having been approved for market yet, there have been various experimental treatments being developed to increase infected person’s chances of survival. As of August 2019, two experimental treatments, REGN-EB3 and mAb-114, have been found to be 90% effective (BBC, 2019). In December 2019, the U.S. Food and Drug Administration (FDA) approved an Ebola virus vaccine, rVSC-ZEBOV, to provide protection to susceptible individuals against the virus and reduce the spread of virus. With limited treatment facilities and access to healthcare, the importance of reducing the spread outside of the hospital setting remains a priority during an Ebola virus outbreak. This report seeks to evaluate the effectiveness of one specific intervention aimed at reducing the spread of the virus: safe and dignified burials of deceased Ebola virus patients. For the purpose of modelling the spread of the virus and the intervention, this report considers the 2018 Ebola virus epidemic which took place in the Democratic Republic of Congo.

Link to report: ebola-intervention-report

Tools:

All coding for the project was done in R.

Link to code: Can be found in the Appendix section of the report.