Health Editor’s Note: What good are mosquitoes? Go ahead. Come up with some response. Fact is that they have no redeeming qualities and add nothing to the earth and those who walk, swim wiggle, etc. on it, both human and animal. If they were extinct, as so many other rather wonderful creatures are, there would be no void, and the human population would climb. Maybe you think an increased population is bad thing. Mosquitos have been around for millions upon millions of years. There is evidence in ancient amber, with some clearly visible inside the fossilized, golden drops of prehistoric tree sap. It seems like mosquitos have been here from the get go.
The thousands of species of mosquitoes or mosquitos (both spellings are correct) are responsible for carrying diseases that kill and maim. Mosquitos are vectors (passes on) for serious diseases. Malaria, yellow fever, dengue fever, Chikungunya, West Nile virus, Zika virus, filariasis, and other arborviruses. It has rightly claimed the title of deadliest animal family. The female mosquito has an organ in her nose (proboscis) which she uses to puncture skin in order to suck blood from mammals, birds, reptiles, amphibians, and even some fish, as well as arthropods. The loss of blood is never the issue. What she leaves behind, in the terms of the above diseases, and if not diseases, the itching that her saliva produces will make her victim (s) miserable.
But back to what this article is all about. Malaria is a parasite that infects a type of mosquito which uses human blood for reproduction purposes. Malaria is mostly found outside the U.S. or in those who have traveled to countries were malaria transmission is endemic. Many of the countries in South Asia and sub-Saharan Africa are rift with malaria causing mosquitos. Under 2,000 cases of malaria are yearly diagnosed in the U.S. If you have malaria, you will be seriously ill with chills, high fever, shaking, and generally feel like you have a horrible case of the flu. Imagine being a small child, pregnant, elderly, or already sick or ill with another disease or disorder.
Sickle cell disease, where the red blood cells become deformed and lose some of its ability to carry oxygen on the hemoglobin, is thought to have developed as a defense mechanism against malaria. Since malaria reproduces and resides in the red blood cells, the red blood cells of these individuals became poor places, due to the non circular shape, in which the malaria could live, enabling these individuals to avoid getting malaria and thus surviving when those around them would become ill and die. Sort of like a mutation that was for the betterment of humans, at least against developing the above mentioned diseases. See, not all mutations are bad. Ask the giraffe if he or she enjoys eating leaves off of trees that no one else can reach? The mutation of a longer neck and the success that the longer neck brought with it for feeding in a niche where others could not, was a good move for the giraffe. Giraffes did not always have necks the length of which they do now.
According the the CDC, in 2016 about 445,000 humans died due to malaria, with most being young children and pregnant women in sub-Saharan Africa even with increased efforts to control malaria. Malaria occurs in poor tropical and subtropical areas and in many of these countries malaria will be the leading cause of illness and death.
With illness and death placed aside, malaria costs governments and individuals in terms of lost days of work, absences from school, expenses of preventative measures, cost of health care, purchase of drugs to treat malaria, expenses to travel to and receive treatment from clinics, maintaining, supplying, and staffing health facilities, purchasing drugs and supplies, cost of public health interventions against malaria, lost economy due to decreased tourism, and perhaps burial expenses.
The best scenario against malaria is to prevent it or if a person has it, to stop the malaria from reproducing and making the person ill. This article describes how that might be accomplished. Let us hope that this works and we can stop at least this portion of devastation passed on by the not so lowly, but extremely successful mosquito. There are other diseases passed on by the mosquito to also work on. Have you come up with a reason for them to be here?…Carol
NIH researchers identify sequence leading to release of malaria parasites from red blood cells
Findings could inform the development of new antimalarial drugs.
Diagram showing the sequence of events involved in rupture of the vacuole and host cell membrane leading to release of the malaria parasite. Using chemical inhibitors, the researchers showed that it’s possible to block each event in the sequence.
The vacuole, a compartment inside human red blood cells in which malaria parasites reproduce and develop, takes on a distinct spherical shape just minutes before its membrane ruptures, leading to the release of parasites into the blood stream, according to researchers at the National Institutes of Health and other institutions. Their study appears in Cellular Microbiology.
The researchers, working with red blood cells from healthy donors, were able to chemically block the sequence of events leading to this rounding of the vacuole. They note that targeting this sequence could inform new treatment strategies against Plasmodium falciparum, the species of malaria parasite that causes the most deaths worldwide and, in several areas, has become drug-resistant.
To track the rounding sequence under a microscope, researchers dyed the membrane of the vacuole with a substance that gives off green light. About 10 minutes before the membrane ruptured, the vacuole morphed from a lumpy, uneven shape to a sphere. Previous studies have shown that malaria parasites use calcium to trigger the biochemical reactions needed for their release from the cell. When the researchers treated the cells with a compound that blocks calcium’s effect, the vacuoles couldn’t transition to the spherical form, trapping the parasites inside the cell.
Joshua Zimmerberg, M.D., Ph.D., Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, is available for comment.
Glushakova S. Rounding precedes rupture and breakdown of vacuolar membranes before malaria parasite egress from erythrocytes. Cellular Microbiology. 2018;e12868. https://doi.org/10.1111/cmi.12868 (link is external)
This press release describes a basic research finding. Basic research increases our understanding of human behavior and biology, which is foundational to advancing new and better ways to prevent, diagnose, and treat disease. Science is an unpredictable and incremental process—each research advance builds on past discoveries, often in unexpected ways. Most clinical advances would not be possible without the knowledge of fundamental basic research.
About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD conducts and supports research in the United States and throughout the world on fetal, infant and child development; maternal, child and family health; reproductive biology and population issues; and medical rehabilitation. For more information, visit NICHD’s website.
About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.