Copyright picture: Illias Teirlinck, De Morgen
Disease control measures during large infectious disease outbreaks rely mainly on counting disease cases, which can result in under- or delayed reporting. I looked at limitations of facility-based disease surveillance relying on case definitions, untapped potential, and alternatives to inform measures faster or more effective.
During outbreaks, case definitions tend to be static, while transmission dynamics or geographical foci change. During the 2014-2016 Ebola outbreak in Guinea, confirming an Ebola infection could take several days, creating a barrier to testing and isolation. A single on-site test combined with clinical and epidemiological data could speed up admission, tailored care, and remove test/isolation barriers. Similarly, during the yellow fever outbreak in DR Congo in 2016, cases were detected only after jaundice, late in disease progression. This delayed patient management and isolation, contact tracing, and local mosquito control.
On the other hand, historical facility-based disease surveillance data, even incomplete or delayed, can help target disease control measures. Because the geographical spread of cholera in the DR Congo is recurrent, we were able to identify areas where outbreaks can be expected, from where cholera spreads, or where case fatality is highest, so these can be prioritised for cholera vaccination or investments in water and sanitation infrastructure.
I then looked into alternative surveillance monitoring risk rather than disease. Using the number of contacts reported from the COVID-19 contact tracing in Brussels, we were able to model the effect of different interventions on epidemic growth, estimating which combination of measures could keep viral circulation low. In low- and middle-income countries, regular measurements of ambulatory antibiotic use may better inform interventions than classical clinical microbiology surveillance of invasive infections. We found in a systematic review on self-medication with antibiotics that more than half of the African population used antibiotics recently, with large differences between countries. An analysis of community-level antibiotic use in Cambodia, DR Congo, Nepal, and Sudan, showed that most antibiotic use could be discontinued after comprehensive diagnostic assessment, and that use of Watch antibiotics, crucial to treat clinically important infections but threatened by antibiotic resistance, was alarmingly high in Nepal and Cambodia. To measure the contribution of each healthcare provider in overall antibiotic use in DR Congo, we combined healthcare utilisation frequencies from household surveys with antibiotic use from patient surveys. More than 50% of antibiotics used, and especially Watch antibiotics, were dispensed through private healthcare providers, which wouldn’t be captured in (public) facility-based surveillance.
Linking routine risk monitoring to facility-based disease surveillance can allow earlier and more targeted prevention/control measures to be deployed.
Prof. dr. Marianne A.B. van der Sande (ITM)
Prof. dr. Marc J.M. Bonten (Utrecht University)
Dr. Esther van Kleef (ITM)
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