Stitching safety nets: the intricate web of Ebola contact tracing

¹Uganda Public Health Fellowship Program-Uganda National Institute of Public Health, Kampala, Uganda, ²Division of Global Health Protection, Global Health Center, US Centers for Disease Control and Prevention, Kampala, Uganda

^&Corresponding author
Rebecca Akunzirwe, Uganda Public Health Fellowship Program-Uganda National Institute of Public Health, Kampala, Uganda

Case study    

Part I

On September 16, 2022, a 26-year-old male from Madudu Subcounty, Mubende District in central Uganda was referred to Mubende Regional Referral Hospital (MRRH) from a private health clinic. At the time of admission, he had a high fever, abdominal pain, diarrhea, chest pain, loss of appetite, dry cough, bloody vomitus, and bleeding from the eyes. Suspecting a viral hemorrhagic fever (VHF), the Mubende District health team isolated the case patient at MRRH. On September 17, they took a blood sample for testing. On September 19, the case patient´s blood sample tested positive for Sudan Virus (SUDV). The next day, the Uganda Ministry of Health declared a Sudan Virus Disease (SVD) outbreak. SUDV is a virus in the Ebolavirus family, any of which can cause Ebola Disease (EBOD). Ebolaviruses are transmitted through exposure to the blood or body fluids of an EBOD case patient. The incubation period is 2 to 21 days, but illness onset generally happens 5-9 days after exposure. Ebola disease typically presents as headache and fever, followed by progressively severe illness involving vomiting, diarrhea, stomach pain, joint pain, loss of appetite, and in some cases patients, hemorrhaging. Even with good medical care, at least half of the infected case-patients die. Persons living with or caring for a case patient with EBOD or who touch the body of an EBOD case patient after death are at the highest risk of infection. However, the infection can also be transmitted through contaminated fomites, such as the sheets or clothing of an infected case patient. Rapid outbreak response is critical once a case-patient is detected, given the transmissibility and high case-fatality rates of the virus.

Question 1: what do you think are some of the major components of an EBOD outbreak response?

Question 2: what is contact tracing in the context of EBOD?

Contact tracing is one of the most important response activities to facilitate EBOD outbreak control. Contact tracing starts when case investigations teams interview the case patient and other people involved in the life of the case patient (family members, friends, coworkers) to gather details about the case patient´s symptoms, the onset of illness, places the case-patient has been, activities they participated in while ill, and potential sources of their infection. During these investigations, they begin listing individuals who have been in contact with the EBOD case patient while he or she was symptomatic. The case investigation teams provide the initial list of contacts to the contact tracing teams, who then begin following up on these contacts. Both contact tracing and case investigation teams may add contacts as their work proceeds in the field. Contacts are monitored by the contact tracing team for 21 days from the date of their last contact with the EBOD case patient. The monitoring involves taking the contacts´ temperature each day and evaluating them for the development of any EBOD symptoms. During the 21 days of follow-up, contacts are asked to stay at home, not work (unless working from home), and avoid interacting with other community members. Contacts who become symptomatic should be isolated and tested immediately (Figure 1). Importantly, for EBOD, people are not infectious until they start feeling sick. In fact, the sicker an EBOD case patient becomes, the more virus they have in their bodies and the more infectious they become. The bodies of persons who have died are at their most infectious state, and handling or touching the bodies of persons who have died of EBOD is extremely high risk (Figure 2).

Question 3: what are the benefits of early isolation and testing for persons exposed to an EBOD case patient who becomes symptomatic?

On September 20, the day after the lab reported the positive test result, the response team got to work immediately. They started by reaching out to health facilities in Mubende District to identify possible case patients that might have been missed in the preceding weeks. They quickly learned that from August 13-September 15, 2022, at least six persons had died in Madudu Subcounty and the neighboring Butoloogo Subcounty (both sub-counties of Mubende District) with bleeding from the eyes and mouth. On September 21, the National Public Health Emergency Operations Center in Kampala, the capital city of Uganda, convened an emergency meeting of the National Task Force (NTF). The NTF set up an incident management team, which appointed an incident commander and various persons to serve as heads of different pillars (pillars represent different areas of public health response, such as surveillance, case management, risk communications, etc.). The surveillance pillar head was instructed to deploy a team to set up and carry out case investigations and contact tracing in Mubende District.

Question 4: for contact tracing, how would you define a 'contact' of a person with EBOD?

Because Uganda has experienced EBOD outbreaks previously, the country conducts periodic simulation exercises and training to ensure that public health staff are trained and ready, should a case patient arise. During July 2022, as part of these preparedness activities, the World Health Organization (WHO) trained health workers on the National Rapid Response Team in EBOD preparedness and response. The training addressed case investigation, contact tracing, and infection prevention and control (IPC). The contact tracing team also received training on communication during EBOD outbreaks, which included skills in good interviewing, empathetic communication, and investigative and interpersonal skills. On September 22, a team of 8 field epidemiologists from the Uganda Public Health Fellowship Program (PHFP, the Advanced Field Epidemiology Training Program in Uganda), and 10 WHO-trained contact tracers were deployed to Mubende District to support surveillance activities, including case investigations and contact tracing. During the surveillance briefing, the team discussed plans to quickly identify contacts of both the confirmed case-patient and the six community deaths.

Question 5: how might the team go about identifying the contacts of those case patients, especially since all had already died?

Question 6: make a list of the information you think would be important to collect from each contact during contact identification and follow-up

The contact tracing team sat together and developed a plan. Since the case-patients had died, they needed to collect information on each of the case-patients from others who knew them. They decided to go jointly to the families of each case patient first, to try to learn as much as they could about the case patient. Then, they would divide up to track down the contacts of the case patients and enroll them in contact follow-up. In Uganda, the culture is extremely hospitable, and visitors to a home are usually offered chairs, food, and drink. Physical contact, such as handshakes or hugs - especially with someone visiting a household multiple times, such as contact tracers - is normal and considered culturally appropriate. Some members of the expanded team expressed fears about the risk of infection during their contact tracing activities, how they should act, and what type of personal protective equipment (PPE) they should wear to protect themselves. The guidelines given to the contact tracing teams were as follows:

When approaching a contact, the contact tracer should: i) introduce themselves and explain their role in the outbreak response. They should clarify that their purpose is to identify potential exposures and provide necessary support and guidance; ii) use clear and simple language to communicate with contacts, avoid medical jargon or technical terms, and educate contacts about EBOD; iii) reassure contacts that all information they provide will be kept confidential and used only for public health purposes. Emphasize the importance of privacy to build trust and cooperation; iv) actively listen to the concerns and questions of contacts. Address their doubts and provide accurate information to alleviate their fears; v) review contact tracing details with each contact. Check for symptoms and measure temperature. For the axillary thermometer, provide each contact with their axillary thermometer, wear gloves, and have them place it in the armpit without touching the case patient. With an infrared thermometer, wear gloves, stand to the side, ask for hair, hat, or glasses adjustments, and point at the right eyebrow from ∼3 cm, the thermometer shouldn´t touch the skin. Do not measure symptomatic contacts; refer for evacuation; vi) be empathetic and informative to contacts - they may not trust you and may be very anxious. Build a friendly relationship, but do not get emotionally involved with the contacts.

For tracing teams: i) eat a good breakfast to avoid getting very hungry in the field; ii) politely decline handshakes or hugs from anyone in the field; iii) do not enter houses and do not sit on chairs while visiting - if offered, explain that the guidelines require standing and staying outside; iv) do not lean on any surfaces, like a wall or a pole, when interviewing contacts; v) politely turn down offers for drinks and food; vi) use 0.05% chlorine solution hand sanitizer frequently when in the field to sanitize hands; vii) use 0.5% chlorine solution to sanitize the bottom of boots; viii) report any breaches or challenges to your supervisor; ix) monitor your temperature each day, and in case of any suspicious symptoms, report immediately to the supervisor. The guidelines also listed the PPE that the teams should be wearing during the contact tracing visits.

Question 7: given the rules above, what type of PPE do you think is needed for contact tracing activities? Defend your ideas.

Unlike COVID, Ebolaviruses are not airborne, and persons who do not come in contact with ill persons or their personal effects are not at risk of infection. Teams deploying to conduct contact tracing, if they follow the guidelines above, need only gumboots and gloves. While it is true that the contacts they are visiting may become ill, if they follow the guidelines and avoid touching contacts or surfaces, they do not need full PPE. Even gloves are unlikely to be strictly necessary. A full Tyvek suit and goggles are not only unnecessary but are also stigmatizing and confusing to the persons being visited and the community. Using them may discourage participation in contact tracing activities. Teams may also want to wear jackets with the logo of their organization, for identification within communities.

Part II

The contact tracing team was given a paper-based tool to list contacts and another tool to monitor each contact for 21 days. The tool that the teams were given for contact listing is shown in Figure 3. It contains information about the EBOD case patient for whom the contacts are being identified, and space to list information about each of the contacts. On September 22, the case investigation and contact tracing teams split into 5 groups and began investigating the seven EBOD case patients (the index case patient and the six community deaths). Their goal was to generate a full list of persons who had been in contact with the case patients while they were symptomatic. Interestingly, they found that speaking to one set of contacts almost always led them to other contacts - for example, when they went to the home of the index case patient to identify household contacts, they were told that he had been sick and treated at a local clinic twice during the week before he died. At the clinic, they gathered information about staff and patients he had been in contact with while ill. They found out from the staff that he had two visitors at the clinic while he was admitted there. Identifying those social visitors required a visit back to his home. When they found the two visitors, they were told that the index case was part of a men´s business group in town that spent time together socializing most days. While the contact tracing team initially thought that they only needed to list contacts from a case patient´s home and workplace, they realized that they actually needed to conduct a thorough case investigation in order to list all of the contacts. The team also realized that the contact list needed to be updated as the numbers kept on growing - their initial lists were insufficient. While the case investigation team continued expanding on the case investigations, the contact tracing team started with the information they already had about the index case-patient from the case investigation team. They built a list of possible contacts for the case patient. The basic information they had on the index case patient indicated that he had had symptom onset on September 8. On September 11, he was taken to a local private health facility where he was admitted until September 13. Due to his worsening condition, his mother took him out of the facility and to a local church for prayers, after which they returned home. On September 16, another local clinic referred him to MRRH, where he died on September 19. He did not work during that time. The initial contact list built by the contact tracing team is below (Table 1).

Question 8: decide which of the above persons in the narrative is a contact requiring follow-up: defend your answer in the last column

In each village, the contact tracing teams worked with community health workers and village chairpersons to identify contacts in the village. Once identified, the contacts were given information on the importance of contact tracing and how it could benefit the contacts if they were exposed. These benefits included access to immediate testing in case of symptoms and prompt treatment if positive (which increases chances of survival). They were also told about the critical role early isolation plays in breaking the chains of transmission and protecting their friends and families.

Question 9: what is the importance of this type of communication to: a) the contacts when they are being enrolled in contact tracing? b) The contact tracing team?

For the next 21 days, contact tracers visited the contacts daily in their homes. During these visits, the contacts´ temperature was recorded, and they were asked about the development of any possible EBOD symptoms. Although contacts were asked to stay at home, many did not, stating that they needed to work. Much of the employment in Uganda is informal, and staying away from work can cause an employer to find a replacement quickly. In addition, many families, especially in rural areas, do not have a financial 'cushion' and live day-to-day on the income they bring in. If the contact was not at home during the visit, they were called by phone. Although phone-based contact tracing was used in these instances, it is generally not recommended by the World Health Organization [1]. The contact was also asked if there were sick people in their family or community with EBOD-like symptoms. Information for each contact was filled into the contact monitoring form (Figure 4) for 21 days. Initially, the contact tracing teams were assigned all the contacts of the case patients they were following. However, after a few days, the teams felt that they were traveling too much each day to be optimally effective. Many case patients had contacts in multiple districts or multiple villages, requiring the teams to move around extensively every day - this was inefficient! After a few days, they decided that they should divide the full list of contacts for all patients geographically, rather than by case-patient. However, this meant that individual case-patient contacts were sometimes split between two or more separate contact tracing teams.

Question 10: what are the advantages of dividing up a case patient´s contacts for follow-up by geography, versus by individual case patient?

Case investigation and contact tracing teams need to work closely together to ensure that information flows frequently and fully in both directions. The case investigation team worked to provide any new contacts they identified to the contact tracing team each day. In turn, the contact tracing team fed back information they learned during their contact visits to the case investigation team.

Part III

Over the subsequent weeks, the outbreak expanded. While some case-patients had just a few contacts, some had dozens of contacts. The contact list grew into the hundreds. At the same time, the contact tracing team hadn´t grown, and the team began to realize that their capacity to visit most of the contacts in person was being outstripped by the growing number of contacts. During an evening meeting, they discussed their options. They would either need to start following more contacts by phone, or they would need to get more contact tracers to support the work. In addition, some teams were becoming tired and requested a rest period. However, they were also concerned that some of the contacts they had been visiting, with whom they had built a trusting relationship, might not feel as comfortable working with new people, and might be less forthcoming with them.

Question 11: would you consider following up with contacts by phone or visiting them at home? Why?

Question 12: the team was tired and some members requested rotating off for rest periods. If you were in charge of the contact tracing teams, would you consider follow-up of contacts by the same contact tracing team for the 21 days of follow-up or changing teams? Why?

Each evening, the contact tracing teams had joint debriefs to share the day´s experiences and challenges. At these meetings, the contact tracing teams combined all their contact tracing data. These summaries were then given to the team lead, who shared them with the surveillance pillar lead daily. An example of a summary report is shown below with the 11 required contact tracing indicators (Table 2).

Question 13: why are each of these indicators needed?

From September 20-29, the outbreak spread beyond Mubende District to Kagadi, Kassanda, and Kyegegwa districts. At least 50 persons had been identified as probable or confirmed case patients or were awaiting test results. Of these, only 15 were previously known as contacts by the contact tracing team. To deal with the expanding needs, the surveillance team requested an increase in the number of contact tracers. In response, the Uganda MoH and supporting organizations recruited additional staff and community health workers.

Part IV

As the outbreak expanded, it became clear that it was no longer practical to keep all the contact tracing information in paper form. It had never been practical. An article from the WHO, written in 2022, shows the universal nature of this problem during contact tracing activities: “We used to use paper, filling out a form each day for every contact. Then at the end of the day, we took the papers to our supervisors, who alerted the doctor if one of the contacts had signs of Ebola. It took a long time.” Lea Kanyere, a contact tracer in the 2018 Ebola outbreak in the Democratic Republic of Congo. In 2019, having recognized this problem, the WHO designed a database called Go.Data [2]. Go.Data is an outbreak investigation database housed at the host country´s Ministry of Health. It consists of a web application that can run either as a standalone or server installation and an optional mobile phone application. When using the mobile phone application, Go.Data may be accessed offline. However, the mobile phone application requires an internet connection to upload data to the web application. Access to the database requires permission from the host institution, usually the Ministry of Health in the country in which the outbreak is occurring. Field-based users, such as field epidemiologists, contact tracers, and laboratory staff who have access rights can register case-patients, contacts, and their related data. It allows contact tracers to easily track all the contacts for follow-up and calculate indicators of contact tracing performance (Figure 5). A decision was made to begin using Go.Data for new contacts.

Question 14: do you support the decision to use Go.Data or would you rather continue using the paper-based system for contact tracing? Why?

The last case patient with SVD in Uganda was reported on November 27, 2022. By that time, a total of 142 confirmed and 24 suspect case patients had been reported and 3,844 contacts had been identified and listed [3] (Table 3).

Question 15: based on the findings from the table above, what can you say about the performance of contact tracing for the SVD outbreak in Uganda (about the proportion of contacts followed up overall and over time and about the proportion completing 21 days of follow-up during the period September-November 2022)?

The effectiveness of contact tracing can be assessed using process indicators. These include calculations of: 1) the proportion of listed contacts that were followed up daily; 2) the proportion of contacts that completed 21 days of follow-up, and 3) the overall/ monthly proportion of confirmed case patients that had been previously identified as contacts before their symptom onset (Table 4).

Question 16: why is it important for case patients to be previously listed as contacts before symptom onset?

Question 17: based on the findings from Table 4, how would you grade the performance of contact tracing? Why?

The contact tracing team faced many challenges in their line of duty, including case patients and contacts providing fake names and addresses, contacts hiding or fleeing, and community resistance. For example, one family in a single village in Mubende District was heavily affected by EBOD, with at least six persons from the household dying in a short period. Nearly all family members refused to be listed as contacts, provided false contact information, or hid from the contact tracing teams. In late September 2022, one of the high-risk contacts left the home after becoming symptomatic and traveled secretly to Kampala to seek care rather than reporting his symptoms to the contact tracers. He became the first case-patient in Kampala, and exposure to this case patient led to additional case patients in Kampala. At this point, the incident management team needed to think about how to intervene.

Question 18: if you were the incident commander in this outbreak, what options would you consider to protect this family and persons who might be exposed to them?

The outbreak response leadership extensively discussed this family, the challenges, and the possible repercussions. On one hand, they did not want to exacerbate the challenges of gaining community cooperation with response activities. On the other, they were deeply concerned about the risk this family posed to the public and the potential for spread, as well as the precedent set if they did not respond strongly. On the night of October 11, security personnel entered the family´s compound and removed the remaining household members, placing them in a local hotel for the remainder of their follow-up period. Contact tracing teams continued to visit them every day.

Part V

Contacts who did not develop SVD-related symptoms after 21 days of follow-up were discharged from follow-up. However, subsequent exposures could lead to them becoming contacts again, which most people wanted to avoid! Once discharged as a contact from possible quarantine or “stay home”, contacts needed to be integrated back into the community.

Question 19: what challenges do you think contacts would face after being discharged from being a contact?

Question 20: what interventions could be put in place to help support contacts during and after contact tracing?

Conclusion     

Contact tracing is essential for a successful EBOD outbreak response. If effectively implemented, contact tracing can contribute significantly to the rapid containment of EBOD outbreaks. Studies of the 2022 SVD outbreak in Uganda demonstrated that case patients who were identified as contacts to existing cases before their symptom onset spent fewer days sick in the community than those who were not identified as contacts, suggesting an important role of contact monitoring in reducing outbreak spread. The same study showed that known contacts had a reduced risk of infecting another person, compared with infected persons who were not known as contacts. Successful contact tracing requires active participation and cooperation from case patients, local leaders, affected communities, and contact tracers. Community engagement and education are vital in building trust and ensuring that contacts willingly participate in the process. Contact tracers should possess good interviewing and counseling skills, be culturally sensitive, and establish a supportive and empathetic relationship with the contacts. It is essential to address the fears and concerns of contacts and provide psychosocial support throughout the contact tracing period. In the 2022 Uganda outbreak, psychosocial challenges were identified for contacts after their discharge from the follow-up process, including stigma from peers, workmates, spouses, and employers. Psychosocial counseling and support were essential to address these challenges and ensure the well-being of the contacts. Despite being the second-largest outbreak of SVD in Uganda, the outbreak ended rapidly, with the last case patients identified only two months after the first case patients were found. Case investigations, contact tracing, contact monitoring, and rapid testing and isolation played a central role in stopping the outbreak. Continuous evaluation and improvement of contact tracing strategies and the provision of necessary resources and support are vital for effective outbreak response and containment.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

All the authors have read and agreed to the final manuscript.

Tables and figures     

Table 1: potential contacts for the index case patient, were identified from early information from the case investigation team

Table 2: summary report of contact tracing indicators

Table 3: monthly number of contacts listed and followed up during the Sudan virus disease outbreak response in Uganda, September-November, 2022

Table 4: monthly number of case-patients listed and those identified as contacts before their onset during the Sudan Virus Disease outbreak response in Uganda, September-November, 2022

Figure 1: process of contact tracing during the ebola disease outbreak in Uganda, 2022

Figure 2: contagiousness of an ebola disease case-patient throughout the illness

Figure 3: sample contact listing form used during the 2022 ebola disease outbreak in Uganda

Figure 4: contact monitoring form

Figure 5: Go.Data interface shows a contact tracing screen; the interface comprises the contact´s name (blinded for confidentiality purposes), a contact ID number, the date the contact tracing team last had contact with them, and the date of the follow-up period ending

References