Malaria

By Keno Ekpokpobe

What is malaria?

Malaria is a parasitic infection transmitted by the bite of female Anopheles mosquitoes. The parasite was visualized in red blood cells by Lavern in 1880. Sir Ronald Ross subsequently proved that the infection was transmissible by mosquitoes to humans in 1897.
Four species of the parasite transmit human malaria: Plasmodium vivax, P. falciparum, P. ovale, and P. malariae. P. vivax and P. falciparum together account for almost 90% of malaria infections globally.
P. falciparum, the most virulent form, is the cause of almost all malaria-associated deaths and severe disease.
P. vivax and P. ovale cause relapsing disease; relapses occur weeks to months after initial illness.

Fast facts on malaria:

• Only the Anopheles mosquito can transmit malaria.
• Malaria is spread by mosquitoes, and it cannot pass directly between people.
• Symptoms resemble those of flu, but, without treatment, the effects can sometimes be long-term and fatal.

Symptoms

Malaria symptoms can be classified into two categories: uncomplicated and severe malaria.

Uncomplicated malaria

This is diagnosed when symptoms are present, but there are no signs to indicate severe infection or dysfunction of the vital organs.

This form can become severe malaria if left untreated, or if the host has poor or no immunity.

Symptoms of uncomplicated malaria typically last 6 to 10 hours and recur every second day. Some strains of the parasite can have a longer cycle or cause mixed symptoms.

In uncomplicated malaria, symptoms progress as follows, through cold, hot, and sweating stages: a sensation of cold with shivering, fever, headaches, and vomiting, seizures sometimes occur in younger people with the disease, sweats, followed by a return to normal temperature, with tiredness

Severe malaria

In severe malaria, clinical or laboratory evidence shows signs of vital organ dysfunction.

Symptoms of severe malaria include:

Fever and chills, impaired consciousness, prostration, or adopting a prone position, multiple convulsions, deep breathing and respiratory distress, abnormal bleeding and signs of anaemia, clinical jaundice and evidence of vital organ dysfunction. Severe malaria can be fatal without treatment.

Causes

Malaria happens when a bite from the female Anopheles mosquito infects the body with Plasmodium. Only the Anopheles mosquito can transmit malaria.

The successful development of the parasite within the mosquito depends on several factors, the most important being humidity and ambient temperatures.

When an infected mosquito bites a human host, the parasite enters the bloodstream and lays dormant within the liver.

The host will have no symptoms for an average of 10.5 days, but the malaria parasite will begin multiplying during this time.

The new malaria parasites are then released back into the bloodstream, where they infect red blood cells and multiply further. Some malaria parasites remain in the liver and are not released until later, resulting in recurrence.

An unaffected mosquito becomes infected once it feeds on an infected individual. This restarts the cycle.

Diagnosis and tests

Early diagnosis is critical for a patient's recovery. Anyone showing signs of malaria should be tested immediately.

The World Health Organization (WHO) strongly advise confirmation of the parasite through microscopic laboratory testing or by a rapid diagnostic test (RDT), depending on the facilities available.

No combination of symptoms can reliably distinguish malaria from other causes, so a parasitological test is vital for identifying and managing the disease.

Prevention and Treatment  

Preventing mosquitoes from biting humans not only reduces the number of people who become infected with the malaria parasite, but also number of infected mosquitoes that can pass the parasite to new human hosts. Prevention can be accomplished by:

Reducing the mosquito population: Methods include killing mosquito larvae (larviciding), killing adult mosquitos through indoor residual spraying (IRS) and with insecticide-treated nets (ITNs) where coverage is sufficiently high, or eliminating breeding sites (source reduction) with various insecticides or biological measures.

Reducing human-mosquito contact (personal protection): Insecticide-treated nets (ITNs) are also a highly effective method for providing individual protection from malaria infection when used correctly and consistently. ITNs are the primary method for prevention of malaria
worldwide.

Treatment aims to eliminate the Plasmodium parasite from the patient's bloodstream. 
Those without symptoms may be treated for infection to reduce the risk of disease transmission in the surrounding population.

Artemisinin-based combination therapy (ACT) is recommended by the WHO to treat uncomplicated malaria. Artemisinin-based combination therapies (ACTs) are highly effective against P. falciparum, the most prevalent and lethal malaria parasite affecting humans.

Artemisinin is derived from the plant Artemisia annua, better known as sweet wormwood. It is known for its ability to rapidly reduce the concentration of Plasmodium parasites in the bloodstream.