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The Epidemiology of Malaria Disease

Essay 2018 7 Seiten

Medizin - Epidemiologie

Leseprobe

Contents

Introduction

Malaria Parasite and Transmission

Hallmark Clinical Presentation Features

Treatment

Prevention and Control Measures

Conclusion

References

Introduction

Malaria is one of the life-threatening infectious diseases whose impacts are experienced in the global healthcare systems. It is known to cause deaths in both endemic and non-endemic regions. Ordinarily, malaria disease i found predominantly within the tropical and subtropical regions where climatic conditions favor survival and transmission of the parasite. Some of the regions where malaria occur are Sub-Saharan Africa, Latin America and southern Asia (Breman, 2013). In regard to the impact of malaria, the disease causes enormous disease burden to the global population. Globally, more than 200 million cases are reported every year. Epidemiological reports indicate that 3.3 billion people from 106 countries and territories experience a high risk of malaria transmission. However, the greatest burden of malaria disease occurs in the African region. In 2010, this region accounted for 91% of the global malaria deaths, whereas South-east Asian region and Eastern Mediterranean region recorded 6% and 3% of deaths, respectively (CDC, 2012). However, it is worth noting that, malaria causes a significant percentage of deaths in non-endemic areas. For instance, in the US, its prevalence reached the highest level in 2011 since 1971. However, most U.S. residents acquired the disease from tropical countries where it is endemic. Epidemiological reports indicate that 70% of malaria cases in 2011were acquired from tropical countries, primarily in Africa (Rettner, 2013).

Malaria Parasite and Transmission

Ordinarily, malaria is caused by Plasmodium parasite and its transmission occurs through the bite of an infected Anopheles mosquitoes. The insect vector transmits the parasite from an infected person through bites (Alonso et al., 2011). When an Anopheles mosquito bites a person suffering from malaria while sucking its blood meal, the parasite enters into its body upon which it undergoes some biological changes in the salivary glands. Thereafter, the parasite is transmitted to a healthy person through a bite which enables it to enter into the body of the new host.

In the infected person, the parasite undergoes two successive asexual replication stages in the human body and infects red blood cells where it produces toxins (Critchlow, Staves & Watt, 2007). The first stage involves the parasite’s multiplication in the liver and then it enters the blood circulation where it infects the erythrocytes causing hemolytic reactions.

However, it is worth noting that, the multiplication of the parasite in the patient’s body depends on the species of the parasite. There are different species of malaria-causing parasite including Plasmodium falciparum, Plasmodium knowlensi, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax. It is reported that Plasmodium falciperum is the most prevalent of all the malaria species. However, Plasmodium vivax and Plasmodium ovale cause chronic malaria owing to the capability of transforming into a dormant state while in the human liver. During the erythrocytic cycle, these malaria species form dormant liver stages which may remain non-infective quite a long time, after which they become active after the symptomless interval. Plasmodium vivax can remain dormant in the human liver for up to 2 years, whereas Plasmodium ovale remain paratenic for up to 4 years (CDC, 2012).

Transmission is additionally dependent on conditions of the climate which can affect the existence and mosquito’s number, like rainfall, humidity and temperature patterns. In several areas, transmission takes places in seasons, with the maximum in and just after the rainy season. Immunity status of an individual is another critical factor, particularly in grownups in areas of moderate or intense conditions of spread. Partial immunity develops in due course with exposure, and it decreases the risk of malaria infection. As a result, most of malaria related mortality happen in children, especially under the age of five years. It is also worth noting that, pregnant mothers are at high risk of being infected by malaria parasites owing to their weak immune responses which are attributable to the fetal development.

Hallmark Clinical Presentation Features

Clinically, the principal signs and symptoms of malaria include headache, fever and vomiting. However, it is worth noting that these characteristics occur within the duration of 10 to 15 days after the bite of an infected Anopheles mosquito. In addition, malaria symptoms occur depending on multiplication stages involved in the liver and blood circulation (WHO, 2013). For instance, chills are manifested during exoerythrocytic cycle in which the parasite becomes infectious. It is believed that destruction of the erythrocytes interferes with the blood supply to various body organs leading to the general body weakness. In most cases, untreated malaria becomes life-threatening after the disruption of the blood circulation in the body in which vital organs lack adequate blood supply.

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Details

Seiten
7
Jahr
2018
ISBN (eBook)
9783668742567
Dateigröße
431 KB
Sprache
Englisch
Katalognummer
v431373
Institution / Hochschule
Egerton University
Note
1
Schlagworte
epidemiology malaria disease

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Titel: The Epidemiology of Malaria Disease