Background
In Syria, disruption to water and sanitation systems, together with poor access to vaccination, forced displacement and overcrowding contribute to increases in waterborne diseases (WBDs). The aim of this study is to perform a spatiotemporal analysis to investigate potential associations between interruptions to water, sanitation, and hygiene (WASH) and WBDs in northeast Syria using data collected by the Early Warning Alert and Response Network (EWARN) from Deir-ez-Zor, Raqqa, Hassakeh and parts of Aleppo governorates.

Methods
We reviewed the literature databases of MEDLINE and Google Scholar and the updates of ReliefWeb to obtain information on acute disruptions and attacks against water infrastructure in northeast Syria between January 2015 and June 2021. The EWARN weekly trends of five syndromes representing waterborne diseases were plotted and analysed to identify time trends and the influence of these disruptions. To investigate a potential relationship, the Wilcoxon rank sum test was used to compare districts with and without disruptions. Time series analyses were carried out on major disruptions to analyse their effect on WBD incidence.

Results
The literature review found several instances where water infrastructure was attacked or disrupted, suggesting that water has been deliberately targeted by both state and non-state actors in northeast Syria throughout the conflict. Over time, there was an overall upwards trend of other acute diarrhoea (OAD, p < 0.001), but downwards trends for acute jaundice syndrome, suspected typhoid fever and acute bloody diarrhoea. For the major disruption of the Alouk water plant, an interrupted time series analysis did not find a strong correlation between the disruption and changes in disease incidence in the weeks following the incident, but long-term increases in WBD were observed.

Conclusions
While no strong immediate correlation could be established between disruptions to WASH and WBDs in northeast Syria, further research is essential to explore the impact of conflict-associated damage to civil infrastructure including WASH. This is vital though challenging given confounding factors which affect both WASH and WBDs in contexts like northeast Syria. As such, research which includes exploration of mitigation after damage to WASH is essential to improve understanding of impacts on quantity and quality of WASH. More granular research which explores the origin of cases of WBDs and how such communities are affected by challenges to WASH is needed. One step towards research on this, is the implementation of adequate reporting mechanisms for real time tracking of the WASH attacks, damages, direct effects, and likely impact in conjunction with environmental and public health bodies and surveillance systems.