MALARIA Malaria is an infectious disease that is common in tropical regions such as Asia, South America and Africa (Cox, 2002). This disease is caused by a parasite that is transmitted to human beings through mosquito bites. Approximately 650 million individuals are infected with malaria each year, of which around 2 million die from difficulty in battling the disease. Most of the victims of malaria are young children and poverty-stricken communities. The vast number of malaria cases around the world has deemed this infectious disease as a serious health problem, causing government and non-government agencies, both local and international, to collaborate and work towards the control and possibly eradication of this health concern.Malaria is caused by the Plasmodium parasite, which is a protest that causes diseases upon transmission to the human system. There are five species of Plasmodium that have been identified, of which Plasmodium falciparum and Plasmodium vivax are considered to be the most life-threatening parasites (Joy et al.
, 2002). The rest of the species, including Plasmodium ovale, P. malariae and P. knowlesi have been determined to have the ability to also infect human beings.
The Plasmodium parasite can be transmitted to human beings through the female mosquito (Anopheles species). After introduction of the parasite into the human bloodstream through a mosquito bite, Plasmodium enters the red blood cells and proliferates, resulting in anemia-like symptoms such as tachycardia, shortness of breath and lightheadedness. The infected individual may also experience fever, nausea and nausea and on the extreme cases may slip into a deep coma or even death. Malaria prevention measures include the employment of mosquito nets and the application of insect repellents. In addition, a particular area may be sprayed with insecticides and stagnant water should be drained because these wet areas are the common areas wherein mosquitoes could lay their eggs.
To date, there is no vaccine that has been designed to prevent the malaria disease. However, preventative medications are available for temporary use during traveling to malaria-borne countries or regions. It has been reported that individuals that reside in areas that are endemic to malaria are actually partially resistant to this infection. However, these individuals may lose their resistance to malaria if they move to another area or country that does not have any malarial cases. This means that they have to take anti-malarial medications if they are going back to their country of origin or even just visiting their home country. The anti-malarial medications that are commonly used include quinine and artemisinin and its derivatives (Kaufman and Rúveda, 2005).
There are approximately 700 million cases of malarial infection around the world every year, of which approximately 3 million of these cases end in death. Most of the casualties involve very young children and pregnant women. Amidst massive efforts to reduce the transmission rates and to increase the therapeutic action against malaria, the frequency of malaria cases has not decreased since 1992. It is predicted the malaria cases will increase in the coming years, resulting in a doubling of the death rate due to this infection.
Malaria is commonly observed in rural areas of Asian countries, the opposite of what has been reported for dengue hemorrhagic fever which is prevalent in cities. However, malaria is common in both rural and urban areas in Africa. Malaria has caused poverty and restricted economic development since these regions of the world often times have no capacity to control this infectious disease. In addition, these regions also have limited capacity to educate its society with regards to the disease.Malaria infection in humans involves two stages of development. The first stage is the exoerythrocytic or hepatic stage, which involves the introduction of sporozoites into an individual’s bloodstream through a mosquito bite. The sporozoites will eventually circulate to the liver and immediately infect the liver cells or hepatocytes.
The sporozoites proliferate inside the hepatocytes asexually and they remain asymptomatic for 1 to 2 weeks. The sporozoites then develop into merozoites which have the capacity to destroy their host cell and spill out into the bloodstream for further circulation and invasion of other types of cells. The merozoites also infect erythrocytes or red blood cells which then results in the second stage of malaria infection, also known as the erythrocytic stage of Plasmodium. The merozoites further mature and travel out of the liver onto the rest of the organs of the body.
Merozoites are often undetected by an individual’s immune system because the parasite has the ability to utilize its host cell as a vector or carrier in moving around the human body, thus rendering it unrecognizable as an invader of the human body. Once a significant number of blood cells have been invaded by the parasite, the infected individual will experience fever and the rest of the symptoms associated with malaria.Malaria infection is often associated with blockage of very small blood vessels and this is generally due to the stickiness or adherence of the infected blood cells onto to wall of the blood vessels. Some of the infected blood cells are destroyed by the spleen, but when massive amounts of infected cells are already circulating, the spleen loses its capacity to destroy as many infected cells as it could and eventually the number of infected blood cells outnumbers the amount of normal blood cells. ReferencesCox F (2002): History of human parasitology.
Clin Microbiol Rev 15(4):595-612. Joy D, Feng X, Mu J (2003): Early origin and recent expansion of Plasmodium falciparum. Science 300(5617):318-21. Kaufman T, Rúveda E (2005): The quest for quinine: those who won the battles and those who won the war. Angew Chem Int Ed Engl 44(6):854-85.