Malaria is the most important parasitic disease in humans. Approximately 5% of the world’s population is infected. Malaria remains one of the major threats to public health and economic development in Africa. It is estimated that three million deaths result from malaria worldwide, with Africa having more than 90% of this burden (1).
Malaria can cause outpatient, inpatient, or admissions of children younger than five years of age at health facilities in Zambia (2). The high burden of malaria in Zambia is because 4.5-5 million new malaria cases are reported annually. The annual incidence rate is 10–100/1,000 people, and this number doubles for children younger than five years of age (3).
The malaria parasite is a mosquito-transmitted protozoan. Plasmodia are sporozoan parasites of red blood cells transmitted to animals (mammals, birds, reptiles) by the bite of mosquitoes. There are four species of Plasmodium (P. falciparum, P. vivax, P. ovale and P. malariae) that can cause malaria in humans and lead to disease (4). In sub-Saharan Africa, most malaria episodes are caused by P. falciparum, which is the agent of the most severe and fatal malaria disease. The transmission of the Plasmodium parasite occurs mainly from person to person through the bite of a female Anopheles mosquito. Rarely can transmission occur through accidents, such as transfusion, inoculation of infected blood from one person to another, or transfer through the placenta from an infected mother to her unborn child. The malaria parasite has a unique life cycle adapted to humans over the years. The life cycles of all Plasmodium species transmitted to humans are the same, with three reproductive phases.
Sporozoites are introduced into the blood when an infected mosquito bites a human. The sporozoites then move on to the liver, where during the next stage, a single cycle of asexual reproduction, known as the hepatic schizogony or preerythrocytic phase, occurs in human liver cells over the course of five to seven days, during which merozoites are produced (4). The term "sporogony" refers to the first stage of the female mosquito life cycle, which includes a single cycle of sexual reproduction and results in the development of sporozoites that infect humans. At 24°C, sporogony occurs in P. falciparum and P. malariae after 9 and 21 days, respectively. When liver cells rupture and infiltrate red blood cells, merozoites reach the bloodstream. The erythrocytic cycle, also known as the third or final phase, comprises numerous cycles of asexual reproduction that take place in red blood cells and persist for approximately 48 hours for P. falciparum, P. ovale, and P. vivax but 72 hours for P. malariae. During each cycle, this phase generates fresh merozoites, which penetrate fresh red blood cells and restart the erythrocytic cycle. However, some of these merozoites differentiate into male and female gametocytes through an unidentified mechanism; these gametes are subsequently ingested by blood-sucking female anopheles to begin the next sporogony cycle.
The clinical manifestations of malaria are dependent on the previous immune status of the host. In areas of intense P. falciparum malaria transmission, asymptomatic parasitaemia is common in adults. Severe malaria is not common in this age group; it is mostly confined to the first years of life and becomes progressively less frequent with increasing age. The majority of childhood malaria infections present with fever and malaise and respond rapidly to appropriate antimalaria treatment.
Symptoms of malaria include high fever and a variety of other symptoms, such as headache, body pains, and nonspecific vomiting (4). The severity of malaria ranges from asymptomatic (mainly in semi-immune populations) to severe and fatal. Severe anemia is a common manifestation of severe malaria in semi-immune children and is responsible for long-term developmental impairments and a high mortality rate in children. Some days after inoculation of the sporozoites, the first symptom was a typical fever. There is a fever peak every 48 hours (P. falciparum) (5). A fever peak appears as a result of the synchronized bursting of blood schizonts. Through asexual division of the parasite, the infected erythrocytes burst and release endotoxins into the blood. The endotoxins are mostly Interleukin-1 and TNF-alpha, which can lead to high fever. Other signs of acute malaria include headache, myalgia (muscle pain) and diarrhea. Malaria-infected children may be asymptomatic, or they may also exhibit vomiting and hypoglycemia (5).
In patients infected with P. falciparum, the sequestration of infected erythrocytes leads to more complications, especially in children. On their surface, infected erythrocytes have special receptors. These conditions lead to adherence to other erythrocytes and to the epithelium of the blood vessels. This prevents removal of the parasite in the spleen. Sequestration leads to cerebral malaria, respiratory distress, and generalized organ failure. Anemia is another important complication in malaria-infected patients (4). Malaria is considered the most consequential parasitic infection in humans. There are as many as 350–500 million clinical episodes per year worldwide (1), and while most estimates of mortality caused by malaria lie at approximately 1 million deaths per year (1), some calculations reach as high as 3 million (3). Almost all of these deaths occur in children (6) living in malaria-endemic countries in sub-Saharan Africa (SSA) (7), where 25% of all childhood deaths before the age of five (approximately 800,000 young children are attributable to malaria) (3). Additionally, more than 15% of those children who survive cerebral malaria suffer neurological deficits (8), which include weakness, spasticity, blindness, speech problems and epilepsy. Where such children are poorly managed and do not have access to specialized educational facilities, these deficits may interfere with future learning and development. Children under the age of five years are at highest risk for malaria because they have not yet acquired protective immunity. People with semi-immune conditions are infected but do not develop severe disease as a rule. In stable transmission areas, newborns are protected by the IgM antibodies of their mother and through breastfeeding. After three months, children are more susceptible to infection by the parasite. In high transmission areas, this disease lasts until the age of 3–5 years. In areas with seasonal transmission, the transmission period can last 10 years. Without reinfection, acquired immunity can disappear within a matter of years (9). Furthermore, children under five years of age experience the greatest malaria burden because they are often superinfected with other parasites and/or often suffer from nutritional deficiencies. These effects lead to a weakened immune system, which leads to increased susceptibility to malaria. Moreover, malaria infection and malnutrition are reasons for an increasing anemia burden in children (10). It is universally accepted that malaria is a disease of public health importance worldwide. The disease causes the greatest suffering and impoverishment among poor people, particularly in Africa.
In 2001, the World Health Organization (WHO) identified malaria as the eighth most significant contributor to the global disease burden, measured by disability-adjusted life years (DALYs), with Africa experiencing the second-highest impact (11). Indeed, the highest incidence of malaria is found among the most impoverished segments of society. This is due to their inability to afford protection from malaria, including improved housing and a clean environment. Additionally, they are particularly susceptible to the consequences of inadequate diagnosis and treatment (12). Annually, the global occurrence of malaria encompasses a range of 300 to 500 million infections, leading to approximately 1 million deaths attributed to malaria. Approximately 90% of these deaths occur in sub-Saharan Africa, and the majority of them occur among women and children. Most of the estimated more than one million malaria deaths every year occur in children up to 5 years old who live in areas where P. falciparum is strongly transmitted, especially in sub-Saharan Africa (13). Malaria also presents major obstacles to the social and economic development of affected countries (14).
Malaria has significant measurable direct and indirect costs and has recently been shown to be a major constraint on economic development. The direct costs of malaria include a combination of personal and public expenditures on both prevention and treatment. Personal expenditures encompass the money spent by individuals or families on items such as insecticide-treated mosquito nets (ITNs), fees for doctors, antimalarial drugs, transportation to health facilities, and financial support for the patient and, at times, a family member accompanying them during hospital stays. Public expenditures include spending by the government on maintaining health facilities and health care infrastructure, publicly managed vector control, education, and research. In certain nations with a significant malaria burden, the disease could constitute up to 40% of public health expenditures. The indirect expenses related to malaria encompass the reduced productivity or income resulting from illness or death. This can be articulated as the expenses incurred due to missed workdays or absenteeism in formal employment, along with the valuation of unpaid household work performed by both men and women. In instances of death, the indirect cost encompasses the discounted future lifetime earnings of the deceased individuals (15).
This study concentrated on the Chiengi and Puta districts, which are situated in the Luapula Province of Zambia. These regions are recognized as areas prone to malaria epidemics and are characterized by an overall prevalence of malarial infection of 50% (12).