MALARIA

Malaria is an insect-transmitted parasitic disease characterized by recurrent episodes of fever and anaemia (loss of blood) in some cases caused by the Plasmodium species which is usually transmitted between mammals through the bite of the female Anopheles mosquito. It is a disease condition in human beings whereby there is an abnormally high body temperature and shivering (or cold) which generally affects the activeness of the affected individual. Malaria is one of the world’s deadliest vector-borne diseases that affect tropical regions of the world especially the sub-Saharan African continent where the disease burden is high. Vector-borne diseases are infectious diseases carried by other living organisms including mosquitoes, sand flies, ticks and water snails amongst others; and these diseases thrive predominantly in communities where environmental sanitation and living standards of the people are poor.

Vectors are living organisms that can transmit infectious diseases or infectious disease agents (parasites) between human beings and from animals to humans. A variety of vectors are blood-sucking in nature and this implies that they feed on human or animal blood during which they ingest pathogenic microorganism(s) that they transfer or inject into the body of susceptible human hosts when they feed on their blood. Typical example is the female Anopheles mosquito that feeds on human blood and ingests Plasmodium parasites (the causative agent of malaria) during the blood meal. The mosquito vector (in this case the female Anopheles mosquito) injects the ingested Plasmodium parasite into a new human host during their next blood meal, and this causes malaria in the later individual.

Malaria is by-far one of the world’s biggest killer infectious disease among the various vector-borne diseases in man. Other killer vector-borne diseases include Onchocerciasis, Schistosomiasis, Yellow fever, Dengue fever, Leishmaniasis and Chagas disease amongst others. Malaria to a great extent represents one of the world’s greatest public health problems, and it accounts for a high percentage of morbidity and mortality across the globe especially in subtropical and tropical countries as aforementioned. Historically, the disease is believed to have affected monkey and ape populations in Asia and Africa; from which it was transmitted to human populations. Malaria which was derived from an Italian word that means “Bad or spoiled Air” was first discovered by Charles Laveran (a French army surgeon) in 1880 from the blood of a soldier suffering from the disease.

Malaria is a disease condition caused by the bites from infected small flying, biting and sucking insects called mosquito. Particularly, the female Anopheles mosquito (a mosquito species responsible for biting and blood sucking) which feeds only on blood meal of animals (humans inclusive) is the vector that helps to transmit the parasite to humans especially after a successful blood meal. Ronald Ross was the first in 1877 to observe the parasitic forms of Plasmodium in the stomach cells of mosquito. This groundbreaking discovery in the malaria epidemic set the landmark for the definition of the different stages of the malaria disease episode (pre-erythrocytic, erythrocytic and sporogonic cycles) in both the mosquito vector and human host. The parasite responsible for the disease is known to live in the erythrocyte (red blood cells) of infected human hosts that has been previously bitten by the mosquito carrying the Plasmodium parasite.

Malaria is a disease that occurs predominantly in the tropical and subtropical regions of the world (Asia and Africa specifically), and it sometimes causes recurrent infections in millions of children and even adults in this part of the world. Despite global and national control strategies for malaria infection, coupled with the development of novel antimalarial drugs, the disease burden of Plasmodium malarial infection still persist. Plethora of programmes including the Roll back Malaria Initiative of the United Nations have all been geared towards finding a lasting solution to the malaria pandemic, yet total cure for the scourge is still far from reach. Though several effective treatment measures are available for malaria infection, the disease still remains a significant human illness worldwide.

Malaria is a major global public health problem, and it is adjudged to be by far one of the most important tropical diseases, causing great pain, suffering and even death to people in the tropic and subtropical regions of the world (Nigeria for example). Other parasitic diseases that are of great concern especially in Africa (which has had its fair share of the malady) according to the Tropical Disease Research (TDR) department of the World Health Organization (WHO) includes: Onchocerciasis, schistosomiasis, filariasis, trypanosomiasis and Leishmania. Together, these diseases (malaria inclusive) affect over 500 million people across the globe. Tropical Africa is endemic with malaria, and the disease according to the World Health Organization (WHO) affects about 350 million people worldwide. Each year over one million of these people die from the disease (according to WHO); and this has made the sickness one of the world’s leading cause of death.

References

Aschengrau A and Seage G.R (2013). Essentials of Epidemiology in Public Health. Third edition. Jones and Bartleh Learning,

Beers M.H., Porter R.S., Jones T.V., Kaplan J.L and Berkwits M (2006). The Merck Manual of Diagnosis and Therapy. Eighteenth edition. Merck & Co., Inc, USA.

Chiodini P.L., Moody A.H., Manser D.W (2001). Atlas of medical helminthology and protozoology. 4^th ed. Edinburgh: Churchill Livingstone.

Dictionary of Microbiology and Molecular Biology, 3^rd Edition. Paul Singleton and Diana Sainsbury. 2006, John Wiley & Sons Ltd. Canada.

Ghosh S (2013). Paniker’s Textbook of Medical Parasitology. Seventh edition. Jaypee Brothers Medical Publishers,

Gillespie S.H and Pearson R.D (2001). Principles and Practice of Clinical Parasitology. John Wiley and Sons Ltd. West Sussex, England.

Gordis L (2013). Epidemiology. Fifth edition. Saunders Publishers, USA.

John D and Petri W.A Jr (2013). Markell and Voge’s Medical Parasitology. Ninth edition.

Kumar V, Abbas A.K, Fausto N and Aster A (2009). Robbins and Cotran Pathologic Basis of Disease. 8^th edition. W.B. Saunders Co, USA.

Lee JW (2005). Public health is a social issue. Lancet. 365:1005-6.

Leventhal R and Cheadle R.F (2013). Medical Parasitology. Fifth edition. F.A. Davis Publishers,

Lucas A.O and Gilles H.M (2003). Short Textbook of Public Health Medicine for the tropics. Fourth edition. Hodder Arnold Publication, UK.

MacMahon   B.,   Trichopoulos   D (1996). Epidemiology Principles and Methods.   2^nd ed. Boston, MA: Little, Brown and Company. USA.

Mandell G.L., Bennett J.E and Dolin R (2000). Principles and practice of infectious diseases, 5^th edition. New York: Churchill Livingstone. 

Molyneux, D.H., D.R. Hopkins, and N. Zagaria (2004) Disease eradication, elimination and control: the need for accurate and consistent usage. Trends Parasitol, 20(8):347-51.

Nelson K.E and Williams C (2013). Infectious Disease Epidemiology: Theory and Practice. Third edition. Jones and Bartleh Learning

Roberts L, Janovy J (Jr) and Nadler S (2012). Foundations of Parasitology. Ninth edition. McGraw-Hill Publishers, USA.

Schneider M.J (2011). Introduction to Public Health. Third edition. Jones and Bartlett Publishers, Sudbury, Massachusetts, USA.