This infectious disease spreads through mosquito bites, and can be lethal.
This disease is known by many as the “queen of parasitosis”, since it is estimated that 40% of the global population is at risk of contracting it, in addition to the 500 million cases that occur annually.
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For all these dizzying figures, it is essential that we all know, at least to some extent, what malaria is and how it is transmitted. Therefore, here we tell you in detail the life cycle of the Plasmodium parasite and the symptoms and treatments for malaria.
Malaria: an inseparable relationship with the mosquito
First and foremost, we see it necessary to introduce malaria from an epidemiological point of viewtag. Such is its incidence at a global level, that these terms are the first to take into account when we talk about the disease. The World Health Organization (WHO) throws various figures to take into account:
- As we have said before, it is estimated that 40% of the population is at risk of this disease.
- This percentage is distributed among 100 countries, among which various African regions stand out.
- It is estimated that 93% of cases are reported in Africa and more than 90% of deaths occur in this region.
- On average, there are between one and two million deaths annually from this disease. The vast majority of them are children.
- Surprising as it may seem, it is estimated that a new case of malaria occurs every 15 seconds.
Despite the impressiveness of these figures, it must be emphasized that this disease knows no ethnic groups. For example, various epidemiological studies estimate that between 10,000 and 300,000 travelers from industrialized countries contract this disease annually. As we can see, the title of infective queen is justified.
Plasmodium and its life cycle
Global figures are essential to understand the epidemiological dynamics of the pathology, but knowing the causal agent is equally important. In this case, we are dealing with various microorganisms of the Plasmodium genus, of the Plasmodiidae family (which includes more than 175 species).
The clinical picture of malaria does not respond to a single organism, since it can be caused by various species: P. vivax, P. ovale, P. malariae, P. knowlesi and Plasmodium falciparum. The latter is of special interest, as it is estimated to be the most lethal and harmful species. Unfortunately, P. falciparum is estimated to be the cause of 99.7% of clinical presentations of the disease in Africa.
This morphologically simple parasite (a circular microscopic protozoan) has an extremely complex life cycletag. Next, we summarize it:
- The sporozoites (one of the forms) of Plasmodium are found lodged in the liver cells of the infected human.
- There they form hepatic schizonts, where a multiplication of the microorganism occurs.
- The schizont ends up fracturing, giving rise to various merozoites.
- These reproduce asexually in red blood cells (going back from schizonts to merozoites, which generates a multiplication of the parasite).
- Some merozoites adopt a sexual form, thus transforming into gametocytes.
- These gametocytes are consumed with the human’s blood by a mosquito.
Due to the terminological complexity of this process, we will spare ourselves the cycle of the parasite inside the mosquito. It is enough to know, in general terms, that the form of the sporozoite ends up in the salivary glands of the invertebrate, which facilitates transmission to a new human when a bite occurs, thus closing the cycle.
As we can see, Plasmodium is a parasite with a cycle that is very difficult to understand , as it infects various cell types and adopts a series of characteristic forms in each of its life stages.
Symptoms
In uncomplicated cases, the symptoms of malaria can be quite nonspecific, making diagnosis very difficult. Even so, it should be emphasized that the clinical picture occurs when the parasites are in the blood, since this reproduction and invasion of red blood cells promotes the rupture and destruction of blood erythrocytes.
The incubation period usually lasts from 6 to 14 days, depending on the patient’s immunological capacity, since previous exposure to the parasite usually delays symptoms. Incredible as it may seem, the longest observed incubation period for the Plasmodium vivax parasite is 30 years.
Once the incubation period is over, various symptoms occur, among which are: fever in more than 90% of cases, fever, chills and diaphoresis (profuse sweating) . Other common but not so prevalent symptoms are dizziness, myalgia, abdominal pain, vomiting, nausea and dry cough.
Severe malaria
As we have said, Plasmodium falciparum is the cause of almost all the severe clinical manifestations of the disease. This occurs when the infection is complicated, either by organ failure in the host or blood abnormalities in the patient. Some of the symptoms considered in this serious clinical picture are cerebral malaria, pulmonary edema, acute kidney failure, severe anemia and profuse bleeding.
This severe form, in the worst cases, can cause death in less than 24 hours. It is shocking to learn that, even in high-income countries, the mortality rate for this clinical picture is 20%, despite extensive care in intensive care units. Without treatment, the mortality rate rises to almost 100%, a value that is not negligible.
Diagnosis
The blood test, in addition to the accessory tests of PCR (Identification of the genetic material of the parasite) and other microbiological methods, is the only differential diagnosis that allows unequivocally to identify malaria. After all, the parasitic forms are housed in red blood cells in the symptomatic phase of the disease.
Treatment
Treatment depends on various factors, among which are the severity of the disease, the species causing the pathology and the geographical location where the infection occurred.
Some of the drugs used are the following: primaquine, chloroquine, atavaquone or quinine. These drugs are used specifically for the state of the parasite, since some attack the hepatic forms and others those found in the bloodstream.
It should be noted that today, due to the rapid expansion of the disease that does not seem to be receding, possible vaccines are being studied for prevention that is now essential. Unfortunately, one that is completely effective has not yet been found.
Conclusions
Malaria is the queen of parasites for various reasons, as we have seen in these lines. With more than 500 million cases per year and a new patient every 15 seconds,we are facing a disease that, far from stopping, continues to deplete human populations in various populations in Africa .
In addition, although we see it as an external pathology to European and American inhabitants, we have been able to see that almost 300,000 people belonging to high-income countries can become infected on business trips or tourism.
In addition, it should be noted that its severe form ends in death in all cases in which no treatment is applied, so it is essential that in low-income countries an effective diagnostic method and a diagnostic method be made available to the general population. free treatment for each and every citizen.
Bibliographic references
- Cohen, J. M., Smith, D. L., Cotter, C., Ward, A., Yamey, G., Sabot, O. J., & Moonen, B. (2012). Malaria resurgence: a systematic review and assessment of its causes. Malaria journal, 11(1), 122.
- Malaria, Centers for Disease Control and Prevention (CDC). Collected on August 2 athttps://www.cdc.gov/dpdx/malaria/index.html
- Malaria, World Health Organization (WHO). Collected on August 2 in
- Tangpukdee, N., Duangdee, C., Wilairatana, P., & Crudsood, S. (2009). Malaria diagnosis: a brief review. The Korean Journal of Parasitology, 47(2),
- Trampuz, A., Jereb, M., Muzlovic, I., & Prabhu, R. M. (2003). Clinical review: Severe malaria. Critical care, 7(4), 315.
- Bruce-Chwatt, L. J., Black, R. H., Canfield, C. J., Clyde, D. F., Peters, W., Wernsdorfer, W. H., & World Health Organization. (1986). Chemotherapy of malaria. World Health Organization.
- WHO Expert Committee on Malaria, & World Health Organization. (2000). WHO Expert Committee on Malaria: Twentieth Report (No. 892). World Health Organization.
- Malaria, R. B. (2005). World malaria report 2005. World Health Organization and UNICEF.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
