The Ugandan government and the World Health Organization recently confirmed an outbreak of Sudan virus disease. The index (first-known) case of this outbreak is thought to be a 32-year-old male nurse from a hospital in Kampala, the capital of Uganda.
Author
- Michael Head
Senior Research Fellow in Global Health, University of Southampton
The WHO reported two main clusters, related to the patient’s family and a hospital cluster. At the time of writing, the index case is the sole recorded death. The second case was the patient’s wife, and as of February 11, there were nine confirmed cases .
Outbreaks of this virus are relatively rare. This new outbreak is the ninth to have been recorded since 1976 when the virus was first identified and – as was practice at the time – named after the location where this first outbreak took place, southern Sudan.
A 2022 Sudan virus outbreak also in Uganda resulted in 164 cases and 77 deaths (a fatality rate of 47%). There are no treatments or vaccines against the Sudan virus.
Sudan virus disease is essentially a disease very similar to Ebola. The Ebola virus has caused several high-profile outbreaks. The west Africa 2014-16 outbreak was the largest with 28,600 cases and 11,325 deaths.
The Sudan and Ebola viruses both come from the orthoebolavirus family, but they have different proteins and genetic components, so the immune response to each virus is different. As such, it’s thought that the Ebola vaccines will not be effective against the Sudan virus.
For the current Sudan virus outbreak, there are efforts to deploy vaccine candidates and also monoclonal antibody medicines. These medicines create antibodies that aim to stop the virus from replicating.
In 2022, the WHO recommended two monoclonal antibodies for use against Ebola. There is enthusiasm for similar research related to treatments for the Sudan virus.
A phase 1 vaccine trial , the earliest phase of testing in humans, is underway.
The similarities in structure between these two types of orthoebolavirus mean that the symptoms in patients are similar. The illness for both viruses may typically begin with fever, aches and fatigue with potential progression onto diarrhoea, vomiting and unexplained bleeding.
Laboratory testing is needed to differentiate between the diseases, though the urgent need for isolation remains.
Early supportive treatment has been shown to reduce mortality rates of Sudan and Ebola virus disease, giving the patient time for their body to recover. This usually involves replacing fluids and treating pain, fever and other possible infections, such as malaria.
The reporting of the 2022 Sudan virus disease outbreak described how patients would first visit care facilities that were outside of the mainstream health service. There were many new infections across late August 2022 from within private health facilities that drove transmission early on in the outbreak. This suggested a low level of infection prevention and control, and quite possibly a lack of equipment and good practice to contain serious infections.
When cases were confirmed, most known contacts who developed symptoms were referred to specialist units for testing and hospital care. These referrals typically happened in October, and the outbreak was declared over by the end of November 2022. Although we lack vital tools such as effective vaccines and drugs, contact tracing and appropriate infection control can contain serious outbreaks such as these.
Climate change driving distribution
Climate change will have an effect on the geographical distribution of new and emerging infections, such as Ebola and Sudan virus disease and the Crimean-Congo virus. Mosquito-borne diseases, such as malaria and yellow fever, will find new habitats while dengue and West Nile virus are already becoming more common in Europe and North America.
International cooperation for addressing global health threats is vital. However, these efforts will be hindered by the volatility and lack of coherence from key stakeholders such as the US government . The world faces uncertain times, and these are ideal circumstances for the Sudan virus and other infectious diseases to thrive.
