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Scientific title: Effectiveness of Malaria Rapid Diagnostic Tests in fever patients attending primary health care facilities in Zanzibar

What did we know before this research?
Over the past decade, Zanzibar has adopted artemisinin-based combination therapy (ACT), long lasting insecticide treated nets and indoor residual spraying. As a result, Zanzibar has turned into a low transmission area with a decline of P. falciparum malaria among children with fever from approximately 30% to 1%, as well as a significant reduction of the crude child mortality. Based on these results, the Zanzibar Ministry of Health officially decided to change the target from control to elimination of malaria.

In order to reach this target, Zanzibar requires a system that provides ACT drugs only to patients who have received a formal positive diagnosis (detection of malaria parasites in the blood). Giving ACT to people who do not have malaria not only leads to the waste of expensive drugs and causes a financial burden on the health care system, but it may prevent other causes of fever from being appropriately treated. This may also increase the risk of drug resistance which could have a devastating effect on global efforts to control the disease.

What does this study add?
Zanzibar has introduced the use of rapid diagnostic tests in all public health facilities as a diagnosis mechanism that confirms the presence of malaria parasites in the blood. The tests are proposed to improve the efficiency of diagnosis, especially in remote areas where microscopy services – a laboratory-based, complex and more expensive diagnosis method – are limited.

This study aims to answer three critical questions. First, whether the same type of rapid diagnostic tests will remain an efficient tool to detect P. falciparum now that Zanzibar is a low transmission area. Second, whether rapid diagnostic tests can be incorporated into Integrated Management of Childhood Illness (IMCI) guidelines to identify malaria among children with fever. Finally, it will investigate whether primary health care workers still prescribe medication based on rapid diagnostic results, given that over 95% of tests have a negative result and alternative tools to diagnose other causes of fever are scarce.

This observational study was conducted in 12 public health facilities during the region's malaria transmission seasonal peak. The team have provided training to staff in all health facilities, including in good clinical practice, IMCI guidelines, use and storage of rapid diagnostic tests, and interpretation of test results.

The research team
Principal Investigator

Prof Anders Björkman, Karolinska Institutet, Sweden

Mr. Mwinyi I. Msellem, Zanzibar Malaria Control Program, Zanzibar

Other Principal investigators

Ass Prof. Andreas Mårtensson, Karolinska Institutet
Mr. Abdullah S. Ali, Zanzibar Malaria Control Program
Dr. Kristina Elfving, Karolinska Institutet
Dr. Delér Shakely, Karolinska Institutet

Latest on this research
There was a significant difference in the sensitivity of HRP-2 based rapid diagnostic test (a test that identifies one type of malarial antigen called histidine-rich protein 2) compared with both microscopy and polymerase chain reaction or PCR (a genetic analysis of malaria infection) to detect Plasmodium falciparum malaria. This means that the sensitivity of rapid diagnostic tests was relatively low.

We have also found that there was an excellent adherence to the test result, meaning that treatment was given according to this formal diagnosis.

Moreover, the results provide evidence that rapid diagnostic tests can be reliably accommodated in the Integrated Management of Childhood Illness (IMCI) as a tool to improve the management of cases of fever in children.

The relatively low sensitivity of rapid diagnostic tests highlights the need to improve quality control of the use of these tests in primary health care facilities, but it also reinforces the need for more sensitive diagnostic tools, especially in the new context of low malaria transmission in Zanzibar.

Learn more about the sub-study of this research, 'Identifying causes of fever in children under five in Zanzibar'.