As many as 10,900 extra malaria deaths may have occurred in 2014 due to the disruption of healthcare services in countries hit by Ebola.

The figure, based on new modelling research from Imperial College London published in The Lancet Infectious Diseases journal, estimates the number of deaths that would have been prevented by health systems functioning normally in Guinea, Sierra Leone, and Liberia.

A further 3,900 deaths may have resulted from disruption to the delivery of insecticide-treated mosquito nets.

The epidemic led to the closure of many health facilities due to the burden of caring for and isolating patients safely and the threat posed to healthcare workers. Among those that stayed open, outpatient attendance fell dramatically - by 90 per cent in many affected areas, according to a World Health Organisation estimate. The number of confirmed Ebola cases has now fallen to its lowest level since May 2014.

The study suggests that the west African Ebola outbreak could have resulted in a comparable number of malaria deaths to those due to Ebola itself (10,704 by 12 April 2015).

The findings also indicate that a mass drug administration campaign of long-lasting malaria treatments, which is now underway, could largely mitigate the impact of Ebola on malaria this year.

“The ongoing Ebola epidemic in parts of west Africa largely overwhelmed already fragile healthcare systems in 2014, making adequate care for malaria impossible and threatening to jeopardise progress made in malaria control and elimination over the past decade,” said lead author Dr Patrick Walker from the MRC Centre for Outbreak Analysis & Modelling at Imperial.

Dr Walker and colleagues analysed demographic and health survey data from 2000 up to the start of the Ebola outbreak in March 2014. They then removed the effect of treatment and hospital care to estimate the potential impact of the ongoing Ebola epidemic on malaria cases and deaths in Guinea, Sierra Leone, and Liberia.

The worst case scenario, assuming that the Ebola epidemic led to a complete end to malaria care, shows that the number of untreated malaria cases could have increased by 45 per cent (1.6 million) in Guinea, 88 per cent (1.3 million) in Sierra Leone, and 140 per cent (520,000) in Liberia in 2014. Around half of these cases would have occurred in children under five. Lapses in mosquito net delivery could have led to another 840,000 malaria cases.

The new estimates also suggest that an absence of clinic and hospital care would have increased malaria deaths by 35 per cent (5,600 deaths) in Guinea, 50 per cent (3,900) in Sierra Leone, and 62 per cent (1,500) in Liberia.

However, the researchers say restoring healthcare provision to pre-Ebola standards could prevent 15,600 malaria deaths in 2015, highlighting the urgent need to support health system recovery.

Their projections suggest that emergency drug treatment campaigns can be a highly effective method to reduce further malaria mortality and the burden of non-Ebola fever cases in the region.

Dr Walker said: “Our predictions highlight the true magnitude of the humanitarian impact caused by the Ebola epidemic. In heavily affected Ebola areas the indirect impact of Ebola upon malaria deaths is likely to be of a similar magnitude to the public health burden caused by cases of Ebola directly. Measures to prevent malaria infection, such as the emergency mass drug administration measures currently recommended by the WHO, are urgently needed while these health systems recover.”

The study was funded by Bill & Melinda Gates Foundation, the Medical Research Council, and the Department for International Development.

Based on a news release from The Lancet.

Reference: P.G.T. Walker et al. ‘Malaria morbidity and mortality in Ebola-affected countries caused by decreased health care capacity, and the potential effect of mitigation strategies: a modelling analysis.’ The Lancet Infectious Diseases, 24 April 2015. DOI: http://dx.doi.org/10.1016/S1473-3099(15)70124-6