Films about epidemics tend to have a common feature: the astute doctor who at some point manages to put the pieces together, realizes what is happening and pinpoints where the epidemic started. Normally, by this point in the movie, many people have fallen sick and the death count is mounting.
These “aha moment” scenes highlight an important feature of epidemics: they start quietly, many times in hard to reach communities, far from astute doctors and hospitals.
Maybe it starts with a child getting sick with some strange symptoms. A child getting sick is, sadly, not news. Children get sick often around the world, and in poor communities even more so because they may be undernourished, may not have access to vaccinations, or even toilets and clean water.
Then another child gets sick, with similar symptoms, and then some adults. But the health center is far, and getting there is costly. There might be some fees to see a doctor or nurse. One mother takes her child to a traditional healer. Another goes to a local drugstore. Others just ride it out at home. Some will die in the community, and the health authorities will not hear about it.
Maybe one child will get very, very sick. Sick enough that the family will do everything in its power to take the kid to a health center. It might take a few hours to get there.
At the primary healthcare center, the attending nurse may not know what this is, but recognize that it’s serious, and send the family to the nearest hospital, which might still be very far away. If they are lucky there will be an ambulance. If not, the family will need to figure out how to take their loved one to the hospital. The hospital might be in a city where they’ve never been to before, and where they speak a different language. They will have to use their hard-earned savings, or even borrow money for the trip and the health care costs.
At the hospital, the child with the strange symptoms is finally seen by an astute doctor. But here’s the catch: No matter how astute the doctor, she is just seeing a single patient. She has no idea that back in that faraway community, several people have fallen sick, and some have died. How is she supposed to guess, from a single case, that this is the start of an epidemic?
Even if the doctor at the hospital is worried enough that she asks for specific laboratory tests, and informs the health and surveillance authorities, things take time. In many countries, only the national laboratories in the capital will have the capacity to run tests for certain diseases. Results may take a week or two.
By the time enough sick people are seen at the hospital so that the astute physician can put the pieces together, there might be five or ten times as many cases in the community. A month or more from the initial case may have gone by. The disease might have spread to neighboring communities.
And yet the astute physician was not the only person who figured out something was wrong. The people living in that community were the first to know. The community knows what the ebb and flow of common diseases looks like for them. They know when something is “off”.
They just didn’t have a way of telling someone who could act on this information.
What if we could change this?
What if we could provide the means, and the confidence, to key community members, so they could inform health authorities when something is wrong in their community? Would this allow us to stop epidemics sooner? To prevent unnecessary disease and deaths?
This is the premise of Community Based Surveillance, a relatively new concept that is all the rage among the people fighting epidemics. Community Based Surveillance, or CBS for short, is “the systematic detection and reporting of events of public health significance within a community by community members”. A definition that was officially agreed by the Technical Contributors to the June 2018 WHO Meeting in France.
But how can community members, who are not doctors, or nurses, or epidemiologists, figure out what is going on? How can they know what this disease is? That there is an outbreak?
That’s not what CBS asks from them. CBS is based on the assumption that communities do not have trained clinicians among them and that they live far away from health care centers. It is also based on the assumption that community members, with appropriate training, can distinguish particular groups of symptoms and raise the alarm if these symptoms meet a “community case definition”. A community case definition is something simple like “any person with three or more loose stools in 24 hours”, which can be used for acute watery diarrhea/cholera.
Now, if you know anything about diarrhea, you might be thinking that this definition is too wide. People get diarrhea for many reasons that have nothing to do with cholera. Many, many cases will be reported if we use this. Same with a “fever and bleeding” definition for potential haemorrhagic fevers such as Ebola.
Yes, that is one downside of CBS, it has what we call a high sensitivity (it will detect a lot of cases) but a low specificity (a lot of those cases will be false positives, i.e. they will be diarrhea, but not cholera, or fever, but not haemorrhagic fever).
That’s why CBS cases need to be counted separately from cases detected by a clinician using a clinical case definition, or cases that have been confirmed by a laboratory test, which are much more stringent. Otherwise we’d be adding pears and apples.
The interesting thing is that, when you train community members on this community case definition for acute watery diarrhea, they will be the first ones to challenge you on it, saying that everyone gets diarrhea but that this is not serious in many cases.
Community members know when things look different or “off”. In different areas, you can tweak and agree on the definition together with them. If they’ve seen cholera, they’ll be able to tell you what it looks like and what are the common terms used to describe it.
But yes, in the end, we will get a lot of “false positives”, that is, reports on people who have indeed some diarrhea, but which is not cholera. That’s ok. What the system needs is a way to weed these out and respond to the true cases.
A key part of CBS is that the community members need a way of communicating the cases they are observing to someone who can raise the alarm, or directly to a health center or a health authority. This can be done in various ways.
We could leverage technology and use an app. But while smartphone use has expanded widely, it is still not common in some remote communities, and they pose other challenges like requiring daily recharging of the battery in places where there might be no electricity.
We can also use the good old clunky mobile phone, either through calls or SMS. These sturdy phones have batteries that last for many days, and SMS are cheap.
The designated community member, upon seeing a case in the community that fits one of the case definitions he or she has been trained on, calls or sends and SMS to a designated person, who might be someone at a health clinic. The designated contact person will ask follow up questions. If the case seems to fit the definition, or there are signs of alarm, the contact person raises the alarm and a clinician from the nearest health center is informed and can come down to the community to investigate.
Once the investigation by the clinician gets triggered, we’ve linked our CBS system into the regular epidemiological surveillance and outbreak investigation system used in the country. Now the normal chain of events and alerts is engaged, where information is shared from the ground and up towards the higher levels of the Ministry of Health through pre-established channels. Cool, eh?
It’s all well and fine to talk about community members detecting signs and symptoms and raising the alarm, but who exactly in the community are we talking about here?
Well, it depends. What we want is people who are well connected in the community and well regarded and trusted by others, so people will come to them to let them know when something is wrong. You want someone with a bit of initiative and self-motivation. It would be good if they can read and write, although this is not always a requisite.
The most important thing is that the community and community leaders agree on having this person designated as the relay for CBS. I’ve seen different models for who becomes a CBS relay.
The Red Cross and Red Crescent Movement is one of the players closest to the communities who are pioneering CBS. In many cases, they already have a great network of volunteers in communities around the world, and many of them are trained in first aid and community health, making them prime candidates for CBS relays.
Many countries have Community Health Workers (CHW), who receive shorter or longer basic health training and are attached to a health center or a health post, and who can be easily trained in CBS.
In other places, pilots are being tested, training teachers and school principals, who in turn teach students about the community case definitions. It’s still too early to say what model works best, and most probably, the “best model” will vary from one context to another.
The key point is that these CBS relays, whoever they are, not only detect people with signs and symptoms and raise the alarm, but are also capable of giving good health prevention advice to the families who report cases to them. For example, in cases of diarrhea, CBS relays counsel on hand-washing, rehydration, correct latrine use and making water safe to drink.
In cases of potential measles (rash and fever), CBS relays advise parents to keep their children out of school. They also refer people to the nearest health center or health post. The idea is that these actions can help stop the transmission of the disease until the clinician can come down to verify what’s going on.
Many issues can preclude CBS from working correctly. How do we keep these CBS relays motivated and engaged, if they are doing this work voluntarily? Should we pay them? Can clinicians at health centers cope with the additional workload required by these visits? Do health centers have the means (motorcycles, fuel, etc) to send their clinicians to investigate? What do we do when there is no mobile phone network?
As any “new” intervention, CBS still needs to prove it’s worth. This is challenging, after all, we are trying to prove that something - i.e. an epidemic outbreak - didn’t happen. But serious efforts are ongoing to measure results and I’m hopeful than in the coming years we’ll start seeing great outcomes.
Acknowledgements: This article came to be thanks to the many opportunities I’ve had of working with the Norwegian and Danish Red Cross, as well as the International Federation of the Red Cross and Red Crescent Societies, in their CBS projects and trainings. It reflects the learnings gained from discussions with many fantastic colleagues.