From the Guidelines
The diagnostic approach to malaria in Papua New Guinea (PNG) should rely on a combination of clinical assessment and parasitological confirmation using rapid diagnostic tests (RDTs) and microscopic examination of Giemsa-stained thick and thin blood smears, as recommended by the most recent and highest quality study 1.
Diagnostic Approach
The gold standard for diagnosis is microscopic examination of Giemsa-stained thick and thin blood smears, which allows for species identification and determination of parasite density. However, due to limited laboratory infrastructure in many parts of PNG, RDTs that detect parasite antigens have become essential diagnostic tools, especially in rural health centers.
- RDTs provide results within 15-20 minutes and require minimal training to perform.
- The sensitivity of RDTs for P. falciparum ranges from 67.9 to 100% and specificity from 93.1 to 100%, while for P. vivax, sensitivity ranges from 66% to 91% and specificity from 98% to 100% 1.
Clinical Assessment
Healthcare providers should first suspect malaria in patients presenting with fever, headache, chills, and fatigue, particularly in endemic regions of PNG where Plasmodium falciparum and Plasmodium vivax are prevalent.
- Clinical findings such as fever, thrombocytopenia, and splenomegaly can support the diagnosis of malaria, but are not specific and can be found in other febrile illnesses.
Quality Control and Training
For effective implementation, healthcare workers should be trained in proper blood sample collection, RDT performance, and microscopy techniques.
- Quality control measures are crucial, including regular maintenance of microscopes and proper storage of RDTs to prevent degradation in PNG's tropical climate.
Justification
This diagnostic approach is justified by the need to distinguish malaria from other febrile illnesses common in PNG, prevent unnecessary antimalarial use that could contribute to drug resistance, and ensure appropriate treatment based on the infecting Plasmodium species.
- The use of RDTs and microscopy can help reduce morbidity and mortality from malaria, and improve the quality of life for patients in PNG.
From the Research
Diagnostic Approach to Malaria in PNG
The diagnostic approach to malaria in Papua New Guinea (PNG) has undergone significant changes in recent years, with a shift from presumptive treatment to the use of rapid diagnostic tests (RDTs) and microscopy 2, 3, 4.
- Availability of Diagnostic Tools: Prior to the introduction of a revised national malaria treatment protocol, the availability of diagnostic tools such as RDTs and microscopy was limited, with only 15% of health facilities having unexpired RDTs in stock or working microscopy available 2.
- Use of RDTs: The use of RDTs has increased significantly since the introduction of the revised protocol, with 53.4% of surveyed health facilities having RDTs available and 68.3% of observed fever cases being tested for malaria by RDT 4.
- Microscopy: Microscopy is also used for malaria diagnosis in PNG, although its availability is limited, with only 3.6% of observed fever patients being tested via microscopy 3.
- Diagnostic Capacity: Despite improvements in the availability of diagnostic tools, diagnostic capacity remains a challenge in PNG, with many health facilities lacking the necessary equipment and trained personnel to perform diagnostic tests 2, 4.
Malaria Case Management
Malaria case management practices in PNG have also undergone significant changes in recent years, with a shift from presumptive treatment to the use of RDTs and microscopy to confirm diagnosis 3, 4.
- Presumptive Treatment: Prior to the introduction of the revised protocol, presumptive treatment was common, with 96.4% of observed fever patients being prescribed an anti-malarial, including 100% of test positive cases and 82% of test negative cases 3.
- RDT-Confirmed Diagnosis: The revised protocol stipulates routine testing of malaria infection by RDT or microscopy, and anti-malarial prescription to test positive cases only 3, 4.
- Adherence to Protocol: Adherence to the revised protocol has improved since its introduction, although full protocol adherence is still rarely observed 4.
Epidemiology of Malaria in PNG
The epidemiology of malaria in PNG varies by region, with some areas experiencing a higher burden of disease than others 5.
- Species Distribution: The species distribution of malaria in PNG varies, with P. falciparum being the most common species in some areas and P. vivax being more common in others 5.
- Incidence: The incidence of malaria in PNG has decreased in recent years, with a steady decline in the reported incidence of all species of confirmed malaria from 2010 to 2013 5.