Malaria
- Fysiobasen
- Oct 14
- 7 min read
Malaria is caused by Plasmodium parasites. The parasites are transmitted to humans through the bites of infected female Anopheles mosquitoes, known as “malaria vectors.” There are five parasite species that can infect humans, two of which—P. falciparum and P. vivax—pose the greatest threat.
Malaria is a life-threatening disease. It is both preventable and curable. In 2018, an estimated 228 million cases of malaria occurred worldwide.[1]
Etiology
Five Plasmodium species can infect humans: P. falciparum, P. ovale, P. vivax, P. malariae, and P. knowlesi.[2][3]
Transmission can also occur via blood transfusion, organ transplantation, sharing needles with infected blood, or by congenital transmission from mother to child. In addition, “airport malaria” can occur when infected mosquitoes are transported from a malaria area to a non-malaria area. In such cases, people may become infected even if they have not traveled abroad.[4]
Once the parasites enter the body, they travel to the liver, where they mature. After a few days, they enter the bloodstream and begin to infect red blood cells. Within 48 to 72 hours the parasites replicate inside the red blood cells, which then rupture. The parasites continue to infect new red blood cells, leading to cyclical symptoms that last 2–3 days at a time.[5]
Epidemiology
According to the latest World Malaria Report (November 2023), there were 249 million malaria cases in 2022, compared with 244 million in 2021. The estimated number of deaths was 608,000 in 2022, compared with 631,000 in 2020.
WHO’s African Region continues to bear a disproportionately high share of the global malaria burden. In 2022, the region accounted for about 93.6% of cases and 95.4% of deaths globally; 78.1% of all deaths were among children under 5 years of age.[7]
Clinical Presentation
Malaria is an acute febrile illness. In non-immune individuals, symptoms usually appear 10–15 days after the infectious mosquito bite.
The initial symptoms (fever, headache, and chills) can be mild and difficult to recognize as malaria. Without treatment within 24 hours, P. falciparum malaria can progress to severe disease that often leads to death. Children with severe malaria frequently develop one or more of the following: severe anemia, respiratory distress due to metabolic acidosis, or cerebral malaria. In adults, multiorgan failure is also common. In malaria-endemic areas, people may develop partial immunity, making infections asymptomatic.[1]
Associated Comorbidities
Severe malaria (P. falciparum) can cause the following complications:
Cerebral malaria
Hypoglycemia
Severe anemia
Pulmonary edema
Respiratory failure
Renal failure
Metabolic acidosis[8]
Cerebral Malaria
Caused only by P. falciparum. Characterized by intense sequestration of parasites in the brain’s small blood vessels, which blocks normal blood flow and prevents the delivery of oxygen and glucose to the brain. Cerebral malaria accounts for over 80% of malaria-related deaths. Symptoms include seizures, lethargy, and focal neurological deficits.[8]
Hypoglycemia
In children this is due to reduced hepatic glucose production because liver cells are infected. In adults it is due to increased insulin production in the pancreas.[8]
Anemia
Due to the loss of red blood cells from destruction of both infected and uninfected cells. Bone marrow function is impaired, leading to reduced erythropoietin production and increased phagocytic activity against red blood cells.[8]
Pulmonary Edema and Respiratory Failure
Inflammatory cytokines increase capillary permeability, which can lead to pulmonary edema, dyspnea, hypoxia, and acute respiratory failure syndrome.[8]
Metabolic Acidosis
Low oxygen delivery to tissues leads to acidosis (increased H⁺ and low pH). The combination of anemia, microvascular obstruction, and hypovolemia contributes to oxygen deficiency.[8]
Antimalarial Drugs
Antimalarial drugs can also be used to prevent malaria. For travelers, malaria can be prevented through chemoprophylaxis, which suppresses the blood stage of malaria and thereby prevents disease. For pregnant women in areas of moderate to high transmission risk, WHO recommends intermittent preventive treatment with sulfadoxine-pyrimethamine at each scheduled antenatal visit after the first trimester. Similarly, in high-transmission areas in Africa, three doses of intermittent preventive treatment with sulfadoxine-pyrimethamine are recommended for infants, delivered alongside routine vaccinations.
Since 2012, WHO has recommended seasonal malaria chemoprevention as an additional intervention in the Sahel subregion of Africa. This involves monthly doses of amodiaquine plus sulfadoxine-pyrimethamine for all children under 5 years during the high-transmission season.[1]
Prevention
Vector control is the primary measure to prevent and reduce malaria transmission. If coverage of vector control in a given area is sufficiently high, it can provide some protection for the entire community.
WHO recommends that all people at risk be protected with effective vector control interventions. Two forms of vector control—insecticide-treated mosquito nets and indoor residual spraying—are effective in many settings.[1]
Vaccines
RTS,S/AS01 (RTS,S) is the first—and to date the only—vaccine shown to reduce malaria, including life-threatening severe malaria, in young children in Africa. The vaccine targets P. falciparum, the deadliest malaria parasite globally and the most common in Africa. Among children who received 4 doses in large clinical trials, the vaccine prevented about 4 out of 10 malaria cases over a 4-year period.[1]
Evaluation
Initial assessment of fever of unknown origin in stable patients with possible malaria exposure includes: complete blood count, metabolic panel, coagulation studies, blood culture, urinalysis, chest X-ray, and microscopy with thick and thin blood smears. With altered mental status and suspected cerebral malaria, it may also be appropriate to check lactate, arterial blood gases, and consider lumbar puncture.
For suspected severe malaria, WHO criteria are used. One or more of the following, together with a positive blood smear for P. falciparum, confirms severe malaria:
Cerebral malaria – impaired consciousness and seizures
Respiratory distress – dyspnea and nasal flaring
Prostration – lying down due to fluid and electrolyte loss
Hyperparasitemia – parasite density ≥ 500,000/mm³
Severe anemia – Hb ≤ 5 g/dL
Hypoglycemia – blood glucose ≤ 5 g/dL
Jaundice – yellow mucosa due to red blood cell breakdown
Renal failure – anuria ≥ 24 hours
Hemoglobinuria – dark urine
Circulatory failure – reduced tissue perfusion
Cessation of oral intake
Persistent vomiting
High fever – ≥ 40°C
Physiotherapy Management
The physiotherapist’s most important role in malaria is to recognize symptoms and promptly refer the patient to a physician for treatment. Rapid diagnosis and treatment reduce morbidity and mortality.[9] Physiotherapists should always be vigilant with patients who have traveled to malaria areas, and malaria should be suspected with fever within the first year after return.[9] However, fever is not always present in malaria. Other symptoms include chills, headache, malaise, nausea, vomiting, diarrhea, abdominal pain, myalgia, back pain, weakness, dizziness, confusion, cough, and/or coma.[9] A thorough history can help prevent transmission and deaths.
Physiotherapists should also educate patients planning travel to malaria areas about preventive measures. CDC is a good resource for travel advice.
Prevention Advice
Alternative (supportive) management is mainly about preventing infection. Chemoprophylaxis is not 100% effective. To avoid mosquito bites, wear long sleeves and pants at dusk in malaria areas, and sleep under an insecticide-treated mosquito net.
Mosquito nets not only prevent bites at night but also kill mosquitoes and help reduce transmission risk across the community.[10] Nets are made of cotton, polyethylene, or polypropylene and are treated with pyrethroids.[10] They remain effective for 6–12 months, while long-lasting insecticidal nets can last up to 3 years.[10][11]
CDC notes that using insecticide-treated nets reduces under-5 child mortality. Clinical studies show that nets reduce morbidity and mortality among people in malaria-endemic areas.[12][13] They are also effective in preventing malaria in pregnant women, but usage remains low in many areas such as Kenya.[14]
Differential Diagnosis
Malaria can resemble many other conditions due to nonspecific symptoms such as fever, chills, headache, and malaise. Nevertheless, malaria is the most likely cause of fever in travelers returning from malaria-endemic areas. Other considerations include:[8]
Influenza – similar symptoms but often with upper respiratory features
Typhoid fever – fever, headache, nausea; often GI symptoms after unsafe food or water
Sepsis
Dengue fever – shorter incubation, often rash, bradycardia
Acute schistosomiasis – often after freshwater exposure in the tropics
Leptospirosis
African tick-bite fever – lymphadenitis and eschar
Sleeping sickness (HAT) – often red rash, cervical lymphadenopathy
Yellow fever – fever, bradycardia, short incubation period
WHO Global Technical Strategy for Malaria 2016–2030
The Global Technical Strategy for Malaria, adopted by the World Health Assembly in 2015, provides a framework for all malaria-endemic countries.
The strategy aims to:
Reduce malaria incidence by at least 90% by 2030
Reduce malaria mortality by at least 90% by 2030
Eliminate malaria in at least 35 countries by 2030
Prevent malaria resurgence in countries that are already malaria-free
The strategy was developed through a two-year process involving more than 400 experts from 70 Member States.[1]
References
WHO Malaria :https://www.who.int/news-room/fact-sheets/detail/malaria
Buck E, Finnigan NA. Malaria. . In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. :https://www.ncbi.nlm.nih.gov/books/NBK551711/
Picture courtesy of http://qspace.library.queensu.ca/dspace/html/1974/421/pfalcip01.htm
Malaria. Centers for Disease Control and Prevention Web Site. http://www.CDC.gov/malaria. Updated June, 2009. Accessed March 1st, 2010.
Healthline Malaria :https://www.healthline.com/health/malaria
Gjennomgått - trukket
World Health Organization. World malaria report 2023. https://www.who.int/publications/i/item/9789240086173
Fairhurst R, Wellems T: Plasmodium Species (Malaria). In: Mandell G, Bennett J, Dolin R. Principles and Practice of Infectious Diseases. 6th Edition. Philadelphia, Pennsylvania: Elsevier Inc; 2005: 3121-3144.
Griffith K, Lewis L, Mali S, Parise M. Treatment of Malaria in the United States. JAMA: Journal of the American Medical Association [serial online]. May 23, 2007;297(20):2264-2277. : Academic Search Premier, Ipswich, MA.
Center for Disease Control: Insecticide-Treated Bed Nets. http://www.cdc.gov/malaria/malaria_worldwide/reduction/itn.html.
Picture courtesy of the President's Malarial Initiative http://www.pmi.gov/technical/itn/index.html
D'Alessandro U. Insecticide treated bed nets to prevent malaria. BMJ (Clinical Research Ed.) [serial online]. February 3, 2001;322(7281):249-250: MEDLINE, Ipswich, MA.
Enserink M. Bed Nets Prove Their Mettle Against Malaria. Science [serial online]. December 14, 2001;294(5550):2271. Available from: Academic Search Premier, Ipswich, MA.
van Eijk A, Blokland I, Slutsker L, et al. Use of intermittent preventive treatment for malaria in pregnancy in a rural area of western Kenya with high coverage of insecticide-treated bed nets. Tropical Medicine & International Health [serial online]. November 2005;10(11):1134-1140. Available from: Academic Search Premier, Ipswich, MA.
