PCR based diagnosis of malaria
Malaria was once known as a deadliest disease throughout the world.in ancient times when there were no facility for disease diagnosis people named it as an air borne diseases that arise from foul smelling marshes, as malaria is an italic word that means bad air. Still it is a major cause of morbidity throughout the world. Thanks to modern diagnosis facilities we know now that the culprit is a tiny animal that cannot be seen with naked eye. Yes it is microscopic protozoan Plasmodium that is carried to human by a vector mosquito who feeds upon blood of human. 5 species of plasmodium are involved in causing malaria in human named as Plasmodium.falciparum, P. vivax, P. ovale , P. malariae and P. knowlesi which basically infect primates but can infect human.
- Malaria may be symptomatic or non-symptomatic.in case of symptomatic malaria, it can be mild or severe. Mild malaria can have any of symptoms like chills, fever, excessive sweating, fatigue, vomiting or headache. These symptoms arise when the disease is not chronic and can be treated easily with antimalarial medication. In the case of severe malaria the disease becomes chronic and the parasite enters in vital organs causing severe damage. Symptoms include severe anemia, multiple organ involvement, liver enlargement, cerebral malaria, respiratory problems due to low oxygen in the body as oxygen carriers red blood cells are destroyed in large number.
- Every year malaria causes a huge number of deaths in poor and developing countries especially in two regions Africa and Asia. Although it is a treatable disease, but due to a lack of diagnostic facilities and poor management of the disease control, it is taking life of people in those regions and main victims are children.
- Different techniques and tools are used for malaria diagnosis now a days. In poor countries doctors rely upon patient’s symptoms for detection while microscopic analysis is considered as gold standard technique in the world. Quantitative buffy coat is based on stratification of blood components by centrifugation and visualization of the parasite with fluorescent microscopy. RDT is gaining popularity throughout the world for malaria diagnosis as it is available in form of kit for detection of parasite antigen with the help of specific antibodies. Molecular methods like PCR (polymerase chain reaction) is a very accurate and sensitive method for identification of parasite DNA in patient’s blood.
- Precise and timely diagnosis is a vital step in effective management of malaria.
- Traditional diagnostic methods like microscopy and rapid diagnostic test (RDT) are error prone and can lead to missed diagnosis. Wrong species identification is frequent with microscopy if the microscopist lacks in expertise level, also it is a time consuming method. Iincorrect diagnosis can lead to consequences like
- Delayed treatment, unwanted side effects of medication & Severe effects on patient’s mental and physical capabilities.
In past the decades PCR based techniques have been successfully utilized for detection of parasitic disease including malaria. They have proved to be quick, more precise, labor extensive and sensitive enough to detect even one parasite per microliter of blood.
PCR based techniques involve extraction of parasite DNA that can be easily done with available kits. In a thermal cycler, target DNA of the parasite is amplified with the help of genus or species specific primers in the presence of polymerase enzyme. Detection is made on gel that show the presence or absence of parasitic DNA.