OVERVIEW
Malaria is an infectious parasitic disease caused by Plasmodium spp. It is a potentially life threatening disease which is spread by the bite of the female Anopheles mosquito, especially common in tropical and subtropical countries.

There are four species of the malarial parasite namely Plasmodium vivax, P ovale, P malariae and P falciparum. Recently, another species Plasmodium knowlesi has been discovered. The most serious and potentially fatal infection is caused by P falciparum

The infection caused by P vivax, ovale and malariae milder and easier to treat is termed benign malaria in comparison to P falciparum infection which is severe and referred to as malignant malaria

LIFECYCLE AND SPREAD OF MALARIA
As described earlier, the malarial parasite essentially develops in two hosts namely mosquitoes and humans to complete its life cycle.

The mosquito becomes infected with the parasite when it bites an infected person. The parasite develops in the mosquito until it reaches a certain stage in its life cycle. When the mosquito bites another human, the parasite is released from the saliva of the mosquito into the bloodstream of the human

From the bloodstream, they travel to the liver, where they undergo further development. After many days, the mature parasites enter the bloodstream and gain entry inside red blood cells. Within 48 to 72 hours, the parasites multiply within the red blood cells, causing the infected cells to burst open (haemolysis).

Unless the infection is diagnosed and treated, more and more red blood cells are infected, resulting in characteristic symptoms that occur in cycles that last two to three days at a time.

As the parasites infect the red cells, malarial infection can be transmitted from one person to another via the following methods

• Sharing of needles (intravenous drug users), and razors
• Organ transplant
• Transfusion of blood and blood products
• Transmission of malaria from pregnant woman to her foetus (congenital malaria)

SIGNS AND SYMPTOMS OF MALARIA
Symptoms of malaria typically develop within 10 days to four weeks following the mosquito bite. In some cases, symptoms may not occur for several months because the malarial parasites can enter the body but remain dormant for long periods of time. Common symptoms of malaria include the following

• Shaking chills that can be severe
• High fever with shaking chills; fever may occur in cycles every 2-3 days
• Headache and generalised tiredness
• Nausea and vomiting
• Diarrhoea
• Abdominal pain
• Profuse sweating
• Muscle pain
• Longstanding malaria can result in haemolytic anaemia due to destruction of red cells

Complications, usually seen in falciparum malaria include kidney failure, liver failure, involvement of lung leading to breathing problems, cerebral malaria with involvement of the brain causing seizures, coma and even death.

DIAGNOSIS OF MALARIA
Early diagnosis and treatment of malarial infection is important to prevent development of complications and anaemia

? History and Physical Examination
A detailed history including travel to malaria endemic areas should be taken. Physical examination may reveal presence of fever, enlarged liver and spleen and raise the clinical suspicion of malaria. Further tests are advised to confirm the diagnosis

? Blood tests
Blood film
A stained blood film may reveal the presence of malarial parasite whose species can then be identified based on appearances. This technique remains the gold standard for laboratory diagnosis of malaria but requires skilled personnel to identify species.

Quantified Buffy Coat (QBC) Diagnosis of Malarial Parasite
The QBC Malaria Test is able to provide rapid malaria detection with a greater level of sensitivity than traditional methods using stained thick blood film. This test is simple and efficient needing less than ten (10) minutes combined for both preparation and review of the slides. It needs a fluorescent microscope to view the stained slides

Antigen Detection and Serology
Several kits are available to diagnose the presence of malarial antigens in the blood and indicates current infection.
Serology detects antibodies against malaria parasites, using either enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence. Serology is not useful to diagnose current infection but identifies past exposure.

? Molecular Diagnosis
Malarial parasite nucleic acids are detected using polymerase chain reaction (PCR). Although this technique may be more sensitive than smear microscopy, it cannot be used for diagnosis of acutely ill patients in routine clinical setting. Also results are often not available quickly enough to be of value in making early diagnosis and starting treatment
PCR is of value in confirming the species of malarial parasite after the diagnosis has been established either by smear microscopy or detection of malarial antigens.

TREATMENT OF MALARIA
If malaria is promptly diagnosed and treated, most people make a complete recovery. Malaria is normally treated using anti-malarial medicines. Quinine, chloroquine and artesunate are some of the medicines available. Mild infections can be treated at home. More severe infections, especially P falciparum infections are treated in the hospital setting

Additionally, certain types of malaria, such as P. vivax and P. ovale, have liver stages of the parasite where the organism remains the body for an extended periods and becomes reactivated at a later date causing recurrent infection. For this form of the parasite, a second medication to prevent a relapse in the future is also given.

Some people may need more than one type of medication or an alternative medication if they develop side-effects. Resistance to anti-malarial medicines has emerged rapidly over the past few decades, especially to Plasmodium falciparum. Therefore, newer medicines or a combination of medicines may be given.

Travellers going to remote places with no access to medical facilities sometimes take emergency medication with them to treat suspected malaria until proper medical care is available.

PREVENTION OF MALARIA
Awareness of risk – While making travel plans discuss with your GP or family physician and be prepared with anti-mosquito measures and medications

Bite Prevention – Protection against mosquito bites by wearing full sleeved clothing and long trousers, applying mosquito repellents containing 30% DEET on skin, sleeping under a net. Synthetic pyrethroids can be vaporised overnight

Chemoprophylaxis – It refers to taking medications to prevent infection. After discussion with the doctor, the medicines should be initiated about two to three weeks before travel and continued for four weeks after return.

Early diagnosis and treatment to prevent complications