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Malaria: Killer at large

By Sola Ogundipe and Chioma Obinna

If there were to be a contest between all known deadly human disorders, malaria would qualify to compete in the heavyweight championship category because it possesses the appropriate credentials.

Regardless of the fact that it is one of the oldest recorded diseases, malaria remains one of the world’s most deadly infectious diseases and arguably, the greatest menace to modern society in terms of morbidity and mortality. Very few disorders compare to the potentiality of malaria to waste human life. Though preventable, treatable and curable, there is no known immunity. This makes it an efficient and unrepentant killer. Several centuries after its discovery, malaria remains a devastating human infection, totalling 300-500 million clinical cases and three million deaths every year.

Somehow, it is almost inconceivable that such a life-threatening parasitic disease as malaria is transmitted through the bite of something as insignificant as the bite of a tiny female Anopheles mosquito, but this only goes to underscore the complexity of the infection. Malaria is a complex disease because everything about it is complex. It is a complex disorder with a complex transmission process. The complexity of the disease vector (the anopheles mosquito) is only exceeded by the complex life cycle of the parasite (plasmodium).

Mosquito

The treatment profile is no less complex, same goes for the prevention process. The level of complication persists, whether one targets the parasite or the vector.

Today approximately 40 percent of the world’s population- mostly those living in the world’s poorest countries – is at risk of malaria. On the average, each Nigerian suffers at least two or more attacks every year and while millions recover, hundreds of thousands are not so lucky. This single disease accounts for about 60 percent of outpatient visits and 30 percent of hospitalisations; 25 percent of deaths in children under one year old; and 11 percent of maternal deaths —a heavy burden on Nigerian families, communities, health system, and workforce.

The burden is worst among young children. Statistics have shown that malaria kills an African child every 30 seconds. Many of those who survive an episode of severe malaria may suffer learning impairments or brain damage. Pregnant women and their unborn children are also particularly vulnerable to malaria, which is a major cause of perinatal mortality, low birth weight and maternal anaemia.

According to the World Health Organisation (WHO) World Malaria Report 2008, the number of annual malaria cases worldwide is actually decreasing, yet the impact of the disease burden remains an enormous challenge. The deadly scourge, along with tuberculosis and HIV/AIDS, is one of the top priority disorders of the modern world. Globally, the disorder remains a major cause of death especially in the tropics but the toll on human life is particularly outstanding in sub-Saharan Africa where mainly children and pregnant women are seriously affected. For sheer numbers and threat to human life. Nigeria is one of Africa’s hardest-hit, accounting for between 30 and 40 percent of malaria deaths on the continent.

According to the World Health Organisation (WHO) a quarter of all malaria cases in Africa occur in Nigeria. This magnitude of occurrence in this part of the world correlates with poverty, ignorance and social deprivations in the community.

With the end of the “Decade to Roll Back Malaria “ in sight, this year,2010, is a milestone for malaria control and there are now just a little over 110 days left to meet the challenge to ensure universal coverage with all anti-malarial interventions.

Although malaria control efforts have helped reduce the global malaria burden, most malaria-endemic countries are not meeting WHO targets for malaria control. Nigeria is amongst the five most malaria-endemic countries in Africa alongside the Democratic Republic of Congo, Ethiopia, Kenya and Tanzania. Together, they account for more than half of the continent’s malaria burden. While interventions have helped reduce malaria cases and deaths less than 50 percent of people at risk have access to insecticide-treated nets last year, the number of ITNs distributed to national malaria control programmes has also improved. But the race is far from over to ensure that the country will meet WHO’s target of 80 percent coverage for the four main malaria treatments: ITNs, artemisinin-based combination therapies, indoor-insecticide spraying programmes and treatment for pregnant women.

In the view of Dr Adeyeye Arigbabuwo Medical Director of Ibijola Medical Centre, Agabara, Lagos, malaria has been quite burdensome over several decades and still remainss a burden especially for population in the endermic areas of the world. Arigbabuwo who is first Vice Chairman, Association of General Private Medical Practitioner Lagos State and National Secretary of Healthcare Providers of Nigeria notes that: “Unfortunately Africa is a known centre for malaria and don’t also forget that even in tropical Africa that is Sub Saharan seems to be at the receiving end of the malaria burden. In fact you can imagine the number of deaths recorded yearly from under five and even pregnant women and expectant mothers.”
He laments that not only that malaria affects virtually all cadre and categories of people in the workforce, it goes to show that the morbidity from malaria tends to affects the Gross National Product (GNP). :Come to think of it, virtually in every home in this country you talk of malaria. You talk of malaria because the environment favours the breed of the female anopheles mosquito which is responsible for this particular disease. Be that as it may, even the various ministries of health have been voting so much on rolling back malaria in the country, certainly the endermic nature of the disease has made their efforts more difficult.”

As to why rolling back malaria may be difficult, the medic attributes this to the penchant of the average Nigerian to seek the clinician’s assistance at the onset of symptoms. “The preference for self medication is high and along the line there may be sub-clinical therapy – that is – giving yourself treatment that is not adequate and this encourages resistant strains. Chloroquine resistance has been well spelt out and because the drug used to be very cheap, access to chloroquine is still there but the efficacy becomes a thing of controversy. These days, you need to use more potent drugs like (ACTs) artemisinin combination therapy and quinine.

But don’t forget some of these drugs also have their side effects. More often than not, it is always advisable to see your doctor before taking these drugs. In our environment people also employ possibilities of herbal remedy in malaria treatment. Some even prefer herbal remedy and it is when they try without success that they rushed back to the hospital although by then complications might have arisen.”
He said one of the biggest effects is that it keeps children away from school. “For the pregnant women, once the parasite attacks the placenta, the woman gets sick and the baby inside of her will also be sick. Some end up with intra- uterine death. The baby may even die in the womb due to malaria complications and there could be other complications.”

The case of malaria and typhoid elicited Arigbabuwo’s interest. “Many misdiagnosed cases of typhoid turn out to be malaria. People are just shouting typhoid. When you are able to go through statistics of WHO, UNDP or Federal Ministry of Health amongst others, when you hear these figures they can be so alarming, then you will begin to wonder if it is true.”

On the possible eradication of malaria, he said: “As physicians, we believe prevention is better than cure. We should learn to maintain personal and environmental hygiene. Bushy environment with stagnant waters, dirty cans containing juices, lying every where are good places for malaria parasite to breed. There is need for attitudinal change. We need more advocacy in that area. If we abide by health education it will go a long way to encourage synergy. Government effort will only be appreciated the more if the people on their own have altitudinal change to ways and pattern of life.
Health burden in Nigeria.

There clear evidences that malaria, together with HIV&AIDS and TB, is one of the major public health challenges undermining development in the poorest countries in the world. The human and economic cost of malaria in Nigeria is staggering. There are currently 110 million clinically diagnosed cases in an estimated population of 151 million. The disorder kills one million people each year, including 250,000 children and is the cause of 11 percent of maternal deaths. 60 percent of out-patient visits and 30 percent of hospitalisations. The financial loss due to malaria annually is estimated to be about N132 billion (USD 906 million) in the form of treatment costs, prevention, loss of man-hours, amongst others.
Government has been collaborating with international organizations, including the World Bank, World Health Organization, UNDP and UNICEF on a campaign to “Roll Back Malaria.”

Recently, it has been found that malaria parasites are developing unacceptable levels of resistance to one drug after another and many insecticides are no longer useful against mosquitoes transmitting the disease. Thanks to years of vaccine research which have produced few hopeful candidates and although scientists are redoubling the search, an effective vaccine is not yet in sight.

Life cycle of the malaria parasite
The life cycle of the malaria parasite in a human or animal begins when an infected mosquito transmits malaria sporozoites to a new host. The sporozoites travel to the liver, where they invade hepatocytes (liver cells) and multiply thousands of times over the following two weeks before rupturing out of the liver into the blood stream. During the first 48 hours after infecting a red blood cell, a parasite goes through several phases of development . The first phase is the ring stage, in which the parasite begins to metabolize hemoglobin. The next phase is the trophozoite stage, during which the parasite metabolizes most of the hemoglobin, gets larger, and prepares to reproduce more parasites. Finally, the parasite divides asexually to form a multinucleated schizont. At the end of the cycle, the red blood cell bursts open and the parasites are dispersed to infect more red blood cells.

Mode of infection
From clinical records, the malaria parasite enters the human host when an infected anopheles mosquito takes a blood meal. Inside the human host, the parasite undergoes a series of changes as part of its complex life-cycle. Its various stages allow plasmodia to evade the immune system, infect the liver and red blood cells, and finally develop into a form that is able to infect a mosquito again when it bites an infected person. Inside the mosquito, the parasite matures until it reaches the sexual stage where it can again infect a human host when the mosquito takes her next blood meal, 10 to 14 or more days later.

Malaria symptoms appear about 9 to 14 days after the infectious mosquito bite, although this varies with different plasmodium species. Typically, malaria produces fever, headache, vomiting and other flu-like symptoms. If drugs are not available for treatment or the parasites are resistant to them, the infection can progress rapidly to become life-threatening. Malaria can kill by infecting and destroying red blood cells (anaemia) and by clogging the capillaries that carry blood to the brain (cerebral malaria) or other
vital organs
Incubation period
The period between the mosquito bite and the onset of the malarial illness is usually one to three weeks (seven to 21 days). This initial time period is highly variable as reports suggest that the range of incubation periods may range from four days to one year. The usual incubation period may be increased when a person has taken an inadequate course of malaria prevention medications. Certain types of malaria parasites can also take much longer, as long as eight to 10 months, to cause symptoms. These parasites remain dormant (inactive or hibernating) in the liver cells during this time. Unfortunately, some of these dormant parasites can remain even after a patient recovers from malaria, so the patient can get sick again. This situation is termed relapsing malaria.

Signs and symptoms

The symptoms characteristic of malaria include flu-like illness with fever, chills, muscle aches, and headache. Some patients develop nausea, vomiting, cough, and diarrohea. Cycles of chills, fever, and sweating that repeat every one, two, or three days are typical. There can sometimes be coughing, and yellowing (jaundice) of the skin and whites of the eyes due to destruction of red blood cells and liver cells.

Diagnosis

Clinical symptoms that have identified malarial risk, suggest malaria as a diagnosis. The classic and most used test is the blood smear on a microscope slide that is stained (Giemsa stain) to show the parasites inside red blood cells. Although this test is easily done, correct results are dependent on the technical skill of the lab technician who prepares and examines the slides with a microscope. Other tests based on immunologic principles exist, including RDT’s (rapid diagnostic tests) and the polymerase chain reaction (PCR) tests. These are not yet widely available and are more expensive than the traditional Giemsa blood smear. Some investigators suggest such immunologic based tests be confirmed with a Giemsa blood smear.

Complications
Contrary to widespread belief, there is nothing “ordinary” about malaria. Every malaria attack is serious and potentially life threatening and should be promptly addressed. People with severe falciparum malaria can develop bleeding problems, shock, liver or kidney failure, central nervous system problems, coma, and can die from the infection or its complications. Cerebral malaria (coma, or altered mental status or seizures) can occur with severe P. falciparum infection. It is lethal if not treated quickly; even with treatment, about 15 percent to 20 percent die.

Treatment
Three main factors determine treatments: the infecting species of the parasite, the clinical situation of the patient (adult, child, or pregnant female with mild or severe malaria), and the drug susceptibility of the infecting parasites. Drug susceptibility is determined by the geographic area where the infection was acquired. The correct drugs for each type of malaria must be prescribed by a doctor who is familiar with malaria treatment protocols. Since people infected with P. falciparum malaria can die (often because of delayed treatment), immediate treatment for P. falciparum malaria is necessary.

Mild malaria can be treated with oral medication; severe malaria (one or more symptoms of either impaired consciousness/coma, severe anaemia, renal failure, pulmonary oedema, acute respiratory distress syndrome, shock, disseminated intravascular coagulation, spontaneous bleeding, acidosis, haemoglobinuria (haemoglobin in the urine), jaundice, repeated generalised convulsions, and/or parasitemia requires intravenous (IV) drug treatment and fluids.

Drug treatment of malaria is not always easy. Although almost all strains of P. malariae are susceptible to chloroquine, unfortunately, resistance is usually noted by drug-treatment failure in the individual patient. There are, however, multiple drug-treatment protocols for treatment of drug resistant Plasmodium strains.

Problem in pregnancy
Malaria may pose a serious threat to a pregnant woman and her pregnancy. The infection in pregnant women may be more severe than in non-pregnant women and may also increase the risk of problems with the pregnancy, including prematurity, abortion, and stillbirth. All pregnant women in malaria-risk area should avoid contracting malaria. Treatment in the pregnant woman requires consultation of a specialist.

Problem in children
All children, including young infants are at risk. Although recommendations for most antimalarial drugs are the same as for adults, it is crucial to use the correct dosage for the child. The dosage of drug depends on the age and weight of the child. Since an overdose of an antimalarial drug can be fatal, all antimalarial (and all other) drugs should be stored in childproof containers well out of the child’s reach.

Prevention
Currently, there is no vaccine available for malaria, but researchers are trying to develop one. Science still has no magic bullet for malaria and many doubt that such a single solution will ever exist. Nevertheless, effective low-cost strategies are available for its treatment, prevention and control and the Roll Back Malaria global partnership is vigorously promoting them in Africa and other malaria-endemic regions of the world. Mosquito nets treated with insecticide reduce malaria transmission and child deaths. Prevention of malaria in pregnant women, through measures such as Intermittent Preventive Treatment and the use of insecticide-treated nets (ITNs), results in improvement in maternal health, infant health and survival. Prompt access to treatment with effective up-to-date medicines, such as artemisinin-based combination therapies (ACTs), saves lives.

Critical observers are of the view that if countries can apply these and other measures on a wide scale and monitor them, then the burden of malaria will be significantly reduced.

Things like avoiding exposure to mosquitoes during the early morning and early evening hours between the hours of dusk and dawn (the hours of greatest mosquito activity) would go a long way. So also would wearing appropriate clothing (long-sleeved shirts and long pants, for examples) especially outdoors and application of insect repellent to the exposed skin in addition to having screens over windows and doors.


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