CU-ICADI 2016 | MAY 9-11| Covenant University Ota, Nigeria

Olabode A. Onile-ere, John O. Openibo, Grace I. Olasehinde

Malaria Diagnosis: Current Approaches, Future Prospects

CU-ICADI 2016 | MAY 9-11| Covenant University Ota, Nigeria

Department of Biological SciencesCovenant University

Ota

Malaria Facts and Figures•Caused by parasites belonging to the genus

Plasmodium

•Five species cause malaria in humans, the deadliest of which is P.falciparum

•Caused over 214 million cases and 438,000 deaths in 2015 (2.68% of global DALYs) (WHO, 2015).

•Children and pregnant women bear the most of the burden (89% of all cases and 91% of all deaths)

•Africa looses an estimated 12-20 Billion USD every year to malaria

•One child dies every minute from malaria in Africa

End of an era- Millennium

Development Goals (MDGs)

Achievements

• Incidence rates decreased by 37% between 2000-2015

• Mortality rates fell by 60%

• 13 Countries eliminated malaria

Challenges

• Inadequate funding (2.4billion USD gap)

• Antimalarial resistance/Insecticide resistance

• Gaps in intervention

Target 6C- Have halted by 2015 and begun to reverse the incidence of malaria and other major diseases

From MDG to Sustainable Development Goals

Eliminating malaria rests on 3 pillars as identified by the WHO(2015)

• Pillar 1- Ensure universal access to malaria prevention, diagnosis and treatment

• Pillar 2- Accelerate efforts towards elimination and attainment of malaria-free status

• Pillar 3- Transform malaria surveillance into a core intervention.

By 2030, end the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases

Table 1 :Roadmap to Malaria Elimination (WHO, 2015)

Can the current diagnostic approaches play their part in getting us to zero?

The Ideal Diagnostic tool•Should be oQualitativeoQuantitativeoSuited to the temperature conditions we have in

AfricaoField deployableoAffordable oAble to detect Sub Microscopic Infections (SMI)oAble to detect drug resistant species

Current Approaches- Malaria Diagnostic Targets

Malaria diagnosis is primarily invasive, utilizing whole blood. Targets of diagnosis include• Histidine Rich Protein II- Increases as parasitemia increases,

persists beyond infection for up to 2 weeks, not quantitative, HRP-II deletion

• pLDH- Non specific antigen, can be used to monitor treatment failure, does not persist in the blood

• Whole cells (infected Red blood cells, iRBCs)- Highly specific and sensitive

• Nucleic Acids- Highly sensitive and specific, quantitative

Current Approaches- Malaria Diagnostic Methods

Malaria diagnosis currently lies on

1.Clinical (presumptive) diagnosis

2.Microscopy

3.Rapid Diagnostic Test kits (RDT)

4.Nucleic Acid Techniques

Current Approaches- Clinical Diagnosis•Most practiced means of diagnosis (Tangpukdee et al.,

2009)•Very cheap and rapid•Based on non specific symptoms presented by

patients- Fever, headache, cold, anorexia•Useful in areas where there is no access to laboratory

services

• Issues•Highly non-specific•Over-diagnosis of malaria as high as 83% (Oladosu &

Oyibo, 2013)•Major contributor to drug pressure and drug

resistance

Current Approaches-Microsocpy•Gold standard of malaria diagnosis (Murphy et al., 2013)•Microscopic examination of giemsa stained blood films•Can detect as low as 5 iRBCs, high specificity and

sensitivity•Relatively affordable

•Useful in monitoring treatment outcome • Issues • Requires expertise (competency)• Requires electricity• Laborious • Human factor• Invasive • Time consuming

Current Approaches- Rapid Diagnostic Tests (RDT)• Immunochromatographic detection of parasite antigens

• Highly effective in diagnosis• Relatively cheap• Field deployable• Requires very little expertise• Qualitative• Sensitivity of about 200 iRBCs• Issues • Over diagnosis due to HRP-II persistence• Cant be used to monitor treatment outcome• Not quantitative • Inability to detect sub-microscopic infections

Current Approaches-Nucleic Acid Techniques•Most sensitive and specific methods of detection

•Techniques include Polymerase Chain Reaction, Gene Probes etc

•Useful in investigating genetic diversity and monitoring drug resistance

•Able to detect SMI• Issues•Not field deployable•Expensive•Requires highly skilled personel and specialised

equipment•Time consuming

Way Forward?

Prospects- Non-invasive approach•Urine and saliva as diagnostic

material •Studies have shown that the

parasite or parasite antigens can be detected in urine and saliva (Pooe et al., 2011; Putaporntip et al., 2011)

•Urine Malaria Test- Recently validated and launched. Detects HRP-II in urine of febrile patients with malaria. •Sensitivity of less than 200 iRBC

(WHO standard=200 iRBCs)•Results in 25 Mins•Cant detect SMI

Prospects- CU Malaria Research Team•Key Persons- Dr. Olasehinde G.I.

•Working towards developing a non-invasive, field deployable, saliva based diagnostic kit

•Demonstrated parasite DNA in Saliva

The Ideal Diagnostic tool•Should be oQualitativeoQuantitativeosuited to the temperature conditions we have in

Africaofield deployableoAffordable oable to detect SMIoAble to detect drug resistant species

ConclusionIt is evident that the current methods cannot deliver on the goal of 2030, as such it is important to take a multifaceted approach to eliminating malaria.

IT BEGINS WITH YOU

Thank you for your time

References• O. O. Oladosu and W. a. Oyibo, “Overdiagnosis and Overtreatment of Malaria

in Children That Presented with Fever in Lagos, Nigeria,” ISRN Infect. Dis., vol. 2013, pp. 1–6, 2013.

• N. Tangpukdee, C. Duangdee, P. Wilairatana, and S. Krudsood, “Malaria diagnosis: A brief review,” Korean J. Parasitol., vol. 47, no. 2, pp. 93–102, 2009.

• S. C. Murphy, J. P. Shott, S. Parikh, P. Etter, W. R. Prescott, and V. A. Stewart, “Review article: Malaria diagnostics in clinical trials,” Am. J. Trop. Med. Hyg., vol. 89, no. 5, pp. 824–839, 2013. vol. 9, no. 1, p. 72, 2010.

• O. J. Pooe, A. Shonhai, and S. Mharakurwa, “A PCR screen for malaria carrier infections using human saliva samples,” African J. Microbiol. Res., vol. 5, no. 28, pp. 5120–5126, Nov. 2011.

• C. Putaporntip, P. Buppan, and S. Jongwutiwes, “Improved performance with saliva and urine as alternative DNA sources for malaria diagnosis by mitochondrial DNA-based PCR assays,” Clin. Microbiol. Infect., vol. 17, no. 10, pp. 1484–1491, Oct. 2011.

• WHO, “Global technical strategy for malaria 2016-2030,” Geneva, 2015.