You will be stunned to know that the second leading cause of death in Africa is Malaria[1]. Yes, you read that right.
According to the World Malaria Report published in 2019, Nigeria recorded the highest percentage of malaria cases worldwide (more than 25% of the global malarial cases in 2018)[2].
Unfortunately, with the highest morbidity rate, the mortality rate was also reported with an astonishing percentage comprising of 24% of the global malarial deaths.
The infection rate is higher in the rural population than the urban population. As per reports, disease prevalence among children under five years of age was found to be 27%.
Contrary to that, Nigeria recorded a double number of cases in rural population than the urban targeting specifically the people living in slums or with low socioeconomic groups[3].
World Health Organization celebrates world malaria day every year on 25th April.
Malaria is an infection caused by a parasite of the genus Plasmodium. Four species of Plasmodium (P.falciparum, P. vivax, P. ovale, and P. malariae)have been discovered. Among all four species, Plasmodium falciparum species is considered to be the leading deadly infectious agent affecting the population in Africa[4].
This parasite spreads to humans through the bite of female anopheles mosquitoes that act as a vector for this parasite.
In Nigeria, malaria is a significant health concern mainly because of two reasons; the first is the diversity of Anopheles vectors, and the second one is the larger size of the country. Where it primarily affects pregnant women and is a significant cause of maternal mortality in Nigeria. It also leads to low birth weight, placental complications, and sometimes neonatal death[5].
Life cycle
Whenever a female anopheles mosquito feeds on human blood containing malarial parasite gametocytes, it gets infected. This female anopheles containing sporozoites in her saliva bites another human and inserts sporozoites through this saliva. This is how the human infection starts.
These sporozoites soon disappear from the blood and enter the liver. After few days, infected hepatocytes rupture, and merozoites leaves the liver and try to invade the RBCs.
In red blood cells, further multiplication of parasites occurs, resulting in the production of trophozoites and then schizonts. After some time, these schizonts rupture and release more merozoites into the blood and cause periodic fever with periodicity depending upon the species of parasite.
In the case of P. vivax and P. ovale, few parasites remain dormant as hypnozoites which can be reactivated even after years and can cause a relapse of the infection. Thus the first attack can occur long after the person has left the area.
This disease can also relapse even after treatment with the drug because the drug can only kill the erythrocytic phase of the parasite.
P. falciparum and P. malariae don’t persist in the exoerythrocytic phase, but fever can occur because of a multiplication of parasites in the red blood cells that were not eliminated by drug treatment and immune processes.
Other modes of transmission:
Because this Plasmodium infects red blood cells, malaria can spread by exposure to infected red blood cells, i.e.
- From mother to child
- Blood transfusion[6]
- Infected syringe
Risk factors
The primary factor for getting malaria infection is to be in areas where the disease is common. Tropical and subtropical regions of Sub-Saharan Africa are notorious for that. Local malaria control, seasonal changes in infection rates, and the precautions are factors determining the degree of risk.
Following people at increased risk of developing the more severe disease in Africa:
- Young children and infants who have not developed partial immunity
- Immunocompromised & older adults
- Travelers that come from areas with no malaria
- Pregnant women[7]
In many African countries with high infection rates, the problem is worsened by a lack of resources, information, and preventive measures.
Residents of the malaria region(Africa) can acquire partial immunity, which lessens the severity of the disease. However, this partial immunity would disappear if one is no longer exposed to the parasite.
Clinical features
In Nigeria, the most common and most dangerous form is P. falciparum infection. Its onset is insidious that occurs with malaise, vomiting, and headache and is usually mistaken for influenza.
Cough and mild diarrhea also happen. Fever has no particular pattern because the release of parasites from schizonts is asynchronous. Jaundice, hepatosplenomegaly, anemia, and thrombocytopenia are also common[8].
The symptoms start appearing on the 1 to 4 week of the infection, depending on the causative agent. For example, patients infected with vivax and ovale experience relapsing fever.
The patient with infection initially presents with fever, flu-like illness, shaking chills, and aches on different parts of the body with a continuous feeling of tiredness. In many cases, the disease starts with persistent fever for several days before the classical fever on alternate days starts.
First, fever starts with rigors and chills. Next, the temperature rises to almost ~40°C, and then the flush phase starts. It lasts for several hours and ends with perspiration and a fall in temperature. All these cycles are completed in 48 hours and then repeats.
As the disease progresses, it affects the vital organs of the body and causing the extensive destruction of red blood cells leading to anemia and jaundice.
In addition, Splenectomy further increases the risk of severe malaria. Children and pregnant mothers are most susceptible and vulnerable to the infection.
When to see a doctor:
If you experience a fever after traveling to or while living in Africa, talk to your doctor. In case of severe symptoms, you must seek emergency medical attention.
Investigations
Although malaria is diagnosed on clinical grounds with a history of a visit to a suspected area or area with a high morbidity rate, however, the gold standard confirmatory diagnostic test is blood smear microscopy[9].
A blood smear is taken from the infected person and checked under a simple microscope. Giemsa-stained thick and thin blood films
- The thick film shows all blood stages of the parasite (the erythrocytes are lysed), thus helps in the diagnosis of even low-level parasitaemia.
- Thin film is essentialto confirm the diagnosis,
- to identify the species of parasite,
- to quantify the parasite load (in P. falciparum infections by counting the % of infected erythrocytes).
Immunochromatographic ‘dipstick’ tests
- OptiMal: detects Plasmodium lactate dehydrogenase of several species
- Parasight F : detects p.falciparum histidine-rich protein 2
These are used for P. falciparum antigens. These provide a useful non-microscopic means of diagnosing this infection. A blood smear is taken from the infected person and checked under a simple microscope. Crescent-shaped cells or banana-shaped cells can be visualized under the microscope.
Management
We can treat malaria only if we opt for the proper regimen. In this way, all parasites will be extracted from the body, but the usage of the wrong drug will cause the disease to persist. The reason why most drugs are ineffective is that they are resistant.
Mild P. falciparum malaria:
Artemisinin-based treatment is recommended for P.falciparum because now it is resistant to chloroquine and sulfadoxine-pyrimethamine, almost worldwide[10]. So, now
- Co-artemether (artemether and lumefantrine) is given (4 tablets at 0, 8, 24, 36, and 60 hours)
- Quinine (600 mg, three times daily for 5–7 days), followed by doxycycline or clindamycin, is alternative
- Doxycycline in pregnancy and artemether in early pregnancy should be avoided.
- WHO is now moving towards ACT(artemisinin-based combination therapy)
Complicated P. falciparum malaria:
If the parasitic count is more than 2% % in any non-immune patient, it is a medical emergency. Its immediate management is
- IV artesunate (2.4 mg/kg IV at 0, 12, and 24 hrs, then daily for seven days)
- After sufficient recovery, oral artesunate (2 mg/kg once daily) can be given.
- IV quinine with ECG monitoring is an alternative.
Non-falciparum malaria:
Oral chloroquine is used for P. vivax, P. ovale and P. malariae infections. (600 mg chloroquine base, followed at 6 hrs by 300 mg, then 150 mg twice daily for two more days).
By taking suppressive doses of anti-malarial drugs, relapses can be prevented. In P. vivax and P. ovale primaquine is used for radical cure.
Complications
When malaria is caused by plasmodium species that are more common in Africa, it can be fatal. The WHO estimates that out of all deaths caused by malaria, about 94% occur in Africa. Malaria-related deaths are usually related to complications.
These complications include:
- Cerebral malaria. It is one of the lethal complications and occurs when parasite-filled blood cells block small blood vessels to the brain (cerebral malaria), leading to swelling of your brain and brain damage. Cerebral malaria can also cause coma and fits.
- Organ failure. Severe malaria may cause hepatic, renal damage, or even splenic rupture. These conditions can be life-threatening.
- Hemolysis. develops in those who are glucose-6-phosphate dehydrogenase (G6PD)-deficient
- Cyanosis. It develops due to the formation of methemoglobin in the red cells, but it is not dangerous.
- Breathing problems. This can lead to pulmonary edema and thus breathing problems[11].
- Anemia. Malaria can cause red blood cell damage and thus leads to anemia.
Prevention
If you live in or are traveling to Africa, preventive steps to avoid mosquito bites must be taken. In case of travel, you should take drugs before, during, and after your journey to African countries to prevent yourself from malaria infection.
To avoid mosquito bites, one should:
- Cover the skin
- Apply insect repellent to skin
- Apply repellent to clothing
- Sleep under a net
Generally, the drugs taken for prophylaxis are the same agents used to treat the infection. Choice of agent for prophylaxis depends on the risk of malaria in the area being visited, duration, and the degree of chloroquine resistance[12].
Various drugs are used, e.g., chloroquine, doxycycline and mefloquine, atovaquone, plus proguanil (Malarone). Mefloquine is helpful in areas of multiple drug resistance, but contraindications exist.
Vaccination
Vaccines against malaria are still developing; this is because of its complicated cycle that scientists are yet unable to make any proper vaccine against this parasite. Some are under experiment, but they are not approved for general usage.
Written by: Emmanuel J. Osemota
References:
[1] E. U. Okeke, “Nigerian malaria: the problems and the fight,” Malar. J., vol. 11, no. S1, pp. 10–12, Oct. 2012, doi: 10.1186/1475-2875-11-s1-p122.
[2] “Malaria.” https://www.who.int/news-room/fact-sheets/detail/malaria (accessed 18th May, 2021).
[3] C. E. Urama, C. O. Manasseh, E. R. Ukwueze, and J. E. Ogbuabor, “Choices and determinants of malaria treatment seeking behaviour by rural households in Enugu state, South-East Nigeria,” Int. J. Heal. Promot. Educ., pp. 1–18, Feb. 2020, doi: 10.1080/14635240.2020.1730703.
[4] R. W. Snow, “Global malaria eradication and the importance of Plasmodium falciparum epidemiology in Africa,” BMC Medicine, vol. 13, no. 1. BioMed Central Ltd., pp. 1–3, 03rd February, 2015, doi: 10.1186/s12916-014-0254-7.
[5] P. G. T. Walker, F. O. ter Kuile, T. Garske, C. Menendez, and A. C. Ghani, “Estimated risk of placental infection and low birthweight attributable to Plasmodium falciparum malaria in Africa in 2010: A modelling study,” Lancet Glob. Heal., vol. 2, no. 8, pp. e460–e467, Aug. 2014, doi: 10.1016/S2214-109X(14)70256-6.
[6] A. K. Owusu-Ofori, C. Parry, and I. Bates, “Transfusion-transmitted malaria in countries where malaria is endemic: A review of the literature from sub-Saharan Africa,” Clinical Infectious Diseases, vol. 51, no. 10. Oxford University Press, pp. 1192–1198, 15th November, 2010, doi: 10.1086/656806.
[7] S. A. Fana, M. D. A. Bunza, S. A. Anka, A. U. Imam, and S. U. Nataala, “Prevalence and risk factors associated with malaria infection among pregnant women in a semi-urban community of north-western Nigeria,” Infect. Dis. Poverty, vol. 4, no. 1, pp. 1–5, Apr. 2015, doi: 10.1186/s40249-015-0054-0.
[8] “Clinical features of malaria,” pp. 191–205, Dec. 2017, doi: 10.1201/9780203756621-7.
[9] M. D. Ughasoro, H. U. Okafor, and C. C. Okoli, “Malaria diagnosis and treatment amongst health workers in University of Nigeria Teaching Hospital Enugu, Nigeria,” Niger. J. Clin. Pract., vol. 16, no. 3, pp. 329–333, Jul. 2013, doi: 10.4103/1119-3077.113456.
[10] O. O. Oladipo, O. A. Wellington, and C. J. Sutherland, “Persistence of chloroquine-resistant haplotypes of Plasmodium falciparum in children with uncomplicated Malaria in Lagos, Nigeria, four years after change of chloroquine as first-line anti-malarial medicine,” Diagn. Pathol., vol. 10, no. 1, pp. 1–8, Jul. 2015, doi: 10.1186/s13000-015-0276-2.
[11] S. Sarkar, K. Saha, and C. S. Das, “Three cases of ARDS: An emerging complication of Plasmodium vivax malaria,” Lung India, vol. 27, no. 3, pp. 154–157, Jul. 2010, doi: 10.4103/0970-2113.68323.
[12] B. Greenwood, “Anti-malarial drugs and the prevention of malaria in the population of malaria endemic areas,” Malaria Journal, vol. 9, no. SUPPL. 3. BioMed Central, pp. 1–7, 13th December, 2010, doi: 10.1186/1475-2875-9-S3-S2.
