World Malaria Day is commemorated on every 25 April. It recognises global efforts to control malaria. The theme for this year’s celebration is “Invest in the future, defeat malaria”, as it has been since 2013. Globally, about 3.3 billion people in 106 countries are at risk of malaria. In 2009, 781 000 people died from malaria, mainly women and children in Africa.
World Malaria Day was established in May 2007 by the 60th session of the World Health Assembly, the decision-making body of the World Health Organisation. The day was established to provide education and understanding of malaria and spread information on year-long intensified implementation of national malaria-control strategies, including community-based activities for malaria prevention and treatment in endemic areas.
The World Malaria Day theme provides a common platform for countries to showcase their successes in malaria control and unify diverse initiatives in the changing global context. Malaria-endemic countries have made incredible gains in malaria in the last decade, but sustaining them will take extra efforts until the job is finished and malaria is eliminated worldwide.
While efforts to prevent, diagnose and treat malaria have gained important momentum over the past years, an annual shortage of US$ 3.6 billion threatens to slow down progress, particularly across Africa where high-burden countries are facing critical funding gaps. Unless the world can find a way to bridge the funding gaps and endemic countries have the resources and technical support they need to implement sound malaria control plans, malaria resurgence will likely take many more lives.
In view of this reality, the National Agency for Food and Drug Administration and Control (NAFDAC) recently entered a partnership with the Cuban government, in order to employ the country’s biotechnology in eradicating malaria in Nigeria.
The Cuban Ambassador, Carlose Trejo Sosa, speaking on the development, said Cuba, as a country rich in biotechnology, could improve the health care of the Nigerian population, under the surveillance of NAFDAC.
“I think and I am sure Nigeria has many things to offer Cuba in the aspect of experience and investigation that have been made in this country, which could be of greatest interest to Cuban people”, Sosa said.
On his part, Dr Paul Orhii, NAFDAC DG, said: “Cuba has a very rich cultural heritage and has good ties with Nigeria; but more importantly, from a health perspective”.
Affirming the authenticity of the partnership, Orhii noted that Cuba is the global leader in biotechnology, developing new technologies to fight diseases, adding that most of the technologies Cuba would be bringing to fight diseases attack diseases in a more natural way.
“For example, the biolarvaesal programme on malaria that we are talking about is not just spreading chemicals that will broadly kill every other thing that will come its way; it specifically targets some disease-causing larvae, all sorts of malaria, and black flies that cause river blindness. As a leader in biotechnology in the whole world, I think we have a lot to gain and learn in this relationship. Even on eliminating malaria alone, you cannot put a naira sign. We are talking about eradicating malaria in Nigeria. We know that anti-malaria drugs are the most often used in high volumes in Nigeria because most people in Nigeria suffer from malaria”, Orhii said.
The partnership with Cuba is just one of several efforts to curb malaria in Nigeria. Hopefully, more initiatives will emerge in the course of the year. However, we shall endeavour to discuss the disease in detail below.
What is malaria?
Malaria is a mosquito-borne infectious disease of humans. It is widespread in tropical and subtropical regions, including much of Sub-Saharan Africa, Asia and the Americas. The disease results from the multiplication of malaria parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases progressing to coma, and death.
Malaria is not just a disease commonly associated with poverty but also a cause of poverty and a major hindrance to economic development. Tropical regions are affected the most; however, malaria’s furthest extent reaches into some temperate zones with extreme seasonal changes. The disease has been associated with major negative economic effects on regions where it is widespread. During the late 19th and early 20th centuries, it was a major factor in the slow economic development of the American southern states.
Globally, the World Health Organisation estimates that in 2013, 198 million clinical cases of malaria occurred, and 500,000 people died of malaria, most of them children in Africa. Because malaria causes so much illness and death, the disease is a great drain on many national economies. Since many countries with malaria are already among the poorer nations, the disease maintains a vicious cycle of disease and poverty.
There are four species of the Plasmodium parasite that can cause malaria in humans: P. falciparum, P. vivax, P. ovale, and P. malariae. The first two types are the most common. Plasmodium falciparum is the most dangerous of these parasites because the infection can kill rapidly (within several days), whereas the other species cause illness but not death. Falciparum malaria is particularly frequent in sub-Saharan Africa and Oceania.
Causes of malaria
You can only get malaria if you’re bitten by an infected mosquito, or if you receive infected blood from someone during a blood transfusion. Malaria can also be transmitted from mother to child during pregnancy.
The mosquitoes that carry Plasmodium parasite get it from biting a person or animal that’s already been infected. The parasite then goes through various changes that enable it to infect the next creature the mosquito bites. Once it’s in you, it multiplies in the liver and changes again, getting ready to infect the next mosquito that bites you. It then enters the bloodstream and invades red blood cells. Eventually, the infected red blood cells burst. This sends the parasites throughout the body and causes symptoms of malaria.
Malaria has been with us long enough to have changed our genes. The reason many people of African descent suffer from the blood disease, sickle cell anaemia, is because the gene that causes it also confers some immunity to malaria. In Africa, people with a sickle cell gene are more likely to survive and have children. The same is true of thalassemia, a hereditary disease found in people of Mediterranean, Asian, or African-American descent.
Symptoms and complications of malaria
Symptoms usually appear about 12 to 14 days after infection. People with malaria have the following symptoms:
- abdominal pain
- chills and sweats
- diarrhoea, nausea, and vomiting (these symptoms only appear sometimes)
- high fevers
- low blood pressure causing dizziness if moving from a lying or sitting position to a standing position (also called orthostatic hypotension)
- muscle aches
- poor appetite
- In people infected with P. falciparum, the following symptoms may also occur:
- anaemia caused by the destruction of infected red blood cells
- extreme tiredness, delirium, unconsciousness, convulsions, and coma
- kidney failure
- pulmonary oedema (a serious condition where fluid builds up in the lungs, which can lead to severe breathing problems)
- vivax and P. ovale can lie inactive in the liver for up to a year before causing symptoms. They can then remain dormant in the liver again and cause later relapses. P. vivax is the most common type in North America.
In recent years, some human cases of malaria have also occurred with Plasmodium knowlesi – a species that causes malaria among monkeys and occurs in certain forested areas of South-East Asia.
Transmission of malaria
Malaria is transmitted exclusively through the bites of Anopheles mosquitoes. The intensity of transmission depends on factors related to the parasite, the vector, the human host, and the environment.
About 20 different Anopheles species are locally important around the world. All of the important vector species bite at night. Anopheles mosquitoes breed in water and each species has its own breeding preference; for example, some prefer shallow collections of fresh water, such as puddles, rice fields, and hoof prints. Transmission is more intense in places where the mosquito lifespan is longer (so that the parasite has time to complete its development inside the mosquito) and where it prefers to bite humans rather than other animals. For example, the long lifespan and strong human-biting habit of the African vector species is the main reason about 90 per cent of the world’s malaria deaths are in Africa.
Transmission also depends on climatic conditions that may affect the number and survival of mosquitoes, such as rainfall patterns, temperature and humidity. In many places, transmission is seasonal, with the peak during and just after the rainy season. Malaria epidemics can occur when climate and other conditions suddenly favour transmission in areas where people have little or no immunity to malaria. They can also occur when people with low immunity move into areas with intense malaria transmission, for instance to find work, or as refugees.
Human immunity is another important factor, especially among adults in areas of moderate or intense transmission conditions. Partial immunity is developed over years of exposure, and while it never provides complete protection, it does reduce the risk that malaria infection will cause severe disease. For this reason, most malaria deaths in Africa occur in young children, whereas in areas with less transmission and low immunity, all age groups are at risk.
When a mosquito bites an infected person, a small amount of blood is taken in, which contains microscopic malaria parasites. About a week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten.
Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery (“congenital” malaria).
Anyone can get malaria. Most cases occur in people who live in countries with malaria transmission. People from countries with no malaria can become infected when they travel to countries with malaria or through a blood transfusion (although this is very rare). Also, an infected mother can transmit malaria to her infant before or during delivery.
Malaria is diagnosed by seeing the parasite under the microscope. Blood taken from the patient is smeared on a slide for examination. Special stains are used to help highlight the parasite. Sometimes, it is possible to identify the species of Plasmodium by the shape of the parasite, especially if gametocytes are seen. Whenever possible, smears should be reviewed by someone with expertise in the diagnosis of malaria. If the smears are negative, they can be repeated every 12 hours. Smears that are repeatedly negative suggest another diagnosis should be considered.
Two types of other tests are available for diagnosis of malaria. Rapid tests can detect proteins called antigens that are present in Plasmodium. These tests take less than 30 minutes to perform. However, the reliability of rapid tests varies significantly from product to product. Thus, it is recommended that rapid tests be used in conjunction with microscopy. A second type of test is the polymerase chain reaction (PCR), which detects malaria DNA. Because this test is not widely available, it is important not to delay treatment while waiting for results.
Antimalarial drug resistance
Resistance to antimalarial medicines is a recurring problem. Resistance of P. falciparum to previous generations of medicines, such as chloroquine and sulfadoxine-pyrimethamine (SP), became widespread in the 1970s and 1980s, undermining malaria control efforts and reversing gains in child survival.
In recent years, there has been a massive reduction in malaria-related morbidity and mortality in regions of high endemicity in the last decade, which was in part due to the effectiveness of the ACT regimen. However, these successes are threatened by the emergence of artemisinin-resistant strains of Plasmodium falciparum from the Thai-Cambodian border and Thai-Myanmar border.
Indeed, artemisinin resistance is a major threat to global health, particularly in low- and middle-income countries (LMICs), in which the disease burden is highest. Substandard or counterfeit ACT compounds are widely available, and systems for the monitoring and containment of resistance are inadequate. There is little existing knowledge regarding ACT-resistant malaria in many SSA countries, including Nigeria, and the most recent reports of ACT treatment failures were in travellers who had recently visited African countries.
Additionally, there have been no reports of delayed parasite clearance in routine therapeutic efficacy studies conducted in Africa. Thus, arguments for the presence of artemisinin resistance in Africa have been based solely on in vitro and/or molecular analyses of parasites collected from autochthonous patients or returning travellers. However, standard in vitro tests are not reliable tools for monitoring artemisinin resistance. In addition, none of the putative molecular markers for antimalarial drug resistance has been correlated with delayed clearance after treatment with artemisinin.
Vector control is the main way to reduce malaria transmission at the community level. It is the only intervention that can reduce malaria transmission from very high levels to close to zero. For individuals, personal protection against mosquito bites represents the first line of defence for malaria prevention.
Two forms of vector control are effective in a wide range of circumstances:
- Insecticide-treated mosquito nets (ITNs)
Long-lasting insecticidal nets (LLINs) are the preferred form of ITNs for public health distribution programmes. WHO recommends coverage for all at-risk persons, and in most settings. The most cost-effective way to achieve this is through provision of free LLINs, so that everyone sleeps under a LLIN every night.
- Indoor spraying with residual insecticides
Indoor residual spraying (IRS) with insecticides is a powerful way to rapidly reduce malaria transmission. Its full potential is realised when at least 80 per cent of houses in targeted areas are sprayed. Indoor spraying is effective for 3–6 months, depending on the insecticide used and the type of surface on which it is sprayed. DDT can be effective for 9–12 months in some cases. Longer-lasting forms of existing IRS insecticides, as well as new classes of insecticides for use in IRS programmes, are under development.
Antimalarial medicines can also be used to prevent malaria. For travellers, malaria can be prevented through chemoprophylaxis, which suppresses the blood stage of malaria infections, thereby preventing malaria disease. In addition, WHO recommends intermittent preventive treatment with sulfadoxine-pyrimethamine for pregnant women living in high transmission areas, at each scheduled antenatal visit after the first trimester. Similarly, for infants living in high-transmission areas of Africa, three doses of intermittent preventive treatment with sulfadoxine-pyrimethamine is recommended delivered alongside routine vaccinations.
Tracking progress is a major challenge in malaria control. In 2012, malaria surveillance systems detected only around 14 per cent of the estimated global number of cases. Stronger malaria surveillance systems are urgently needed to enable a timely and effective malaria response in endemic regions, to prevent outbreaks and resurgences, to track progress, and to hold governments and the global malaria community accountable.
Malaria elimination is defined as interrupting local mosquito-borne malaria transmission in a defined geographical area, i.e. zero incidences of locally contracted cases. Malaria eradication is defined as the permanent reduction to zero of the worldwide incidence of malaria infection caused by a specific agent; i.e. applies to a particular malaria parasite species.
On the basis of reported cases for 2013, 55 countries are on track to reduce their malaria case incidence rates by 75 per cent, in line with World Health Assembly targets for 2015. Large-scale use of WHO-recommended strategies, currently available tools, strong national commitments, and coordinated efforts with partners, will enable more countries – particularly those where malaria transmission is low and unstable – to reduce their disease burden and progress towards elimination.
In recent years, four countries have been certified by the WHO Director-General as having eliminated malaria: United Arab Emirates (2007), Morocco (2010), Turkmenistan (2010), and Armenia (2011).
Vaccines against malaria
There are currently no licensed vaccines against malaria or any other human parasite. One research vaccine against P. falciparum, known as RTS, S/AS01, is the most advanced. This vaccine has been evaluated in a large clinical trial in seven countries in Africa and has been submitted to the European Medicines Agency under art. 58 for regulatory review. A WHO recommendation for use will depend on the final results from the large clinical trial and a positive regulatory review. The recommendation as to whether or not this vaccine should be added to existing malaria control tools is expected in late 2015.
The choice of drug depends on the species of Plasmodium and the risk of drug resistance in the area where the malaria was acquired. In sub-Saharan Africa, for example, older drugs like chloroquine are largely ineffective.
Most medications are available only as tablets or pills. Intravenous treatment with quinidine may be needed in severe malaria or when the patient cannot take oral medications. Malaria during pregnancy requires treatment by someone who is an expert in this area. Miscarriage and maternal death may occur, even in the best of hands.
Patients with P. vivax or P. ovale may not be completely cured by the above medications, even though the symptoms resolve. This is because the parasites can hide in the liver. A medication called primaquine is used to eradicate the liver form, but this drug cannot be given to people who are deficient in an enzyme called G6PD.
Treatment usually lasts for 3 to 7 days, depending on the medication type. To get rid of the parasite, it’s important to take the medication for the full length of time prescribed – don’t stop taking the medication even if you feel better. If you experience any side effects, your doctor can recommend ways to manage them or may choose to give you a different medication.
If you’re travelling to a malarial region, you should take a course of preventive treatment. Medications similar to those used to cure malaria can prevent it if taken before, during, and after your trip. It’s vital to take your medication as prescribed, even after you return home. Before travelling, check with your doctor or travel clinic about the region’s malaria status.
Reports compiled by Temitope Obayendo with additional information from: The World Health Organisation (WHO); National Agency for Food and Drug Administration and Control (NAFDAC); bodyandhealth.com; and cutecalendar.com