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MALARIA

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Mosquito - A small fly, occurring worldwide, especially in the tropics. It has long legs and a slender abdomen. In most species the males feed on plant juices, while the females suck the blood of mammals, often transmitting serious diseases - including malaria and yellow fever.

Malaria -  A serious, acute and chronic relapsing infection in humans, an infectious disease caused by a protozoa of the genus Plasmodium. Characterized by periodic attacks of chills and fever, anemia, and enlargement of the spleen - splenomegaly, very often casing fatal complications, or great illness. The protozoa is a member of any a large group of single-celled, usually microscopic, eukaryotic organisms, such as amoebas, ciliates, flagellates, and sporozoans

Malaria is spread by the female Anopheles mosquito, which lives only in the tropics.

Different species of Plasmodium cause different types of Malaria. Malignant Tertian Malaria, caused by P. falciparum, is the most severe; benign tertian malaria, caused by P. vivax,  is less often fatal but there are repeated attacks.

A female mosquito feeds on blood, and must feed on blood, not necessarily to live, but to ingest the nutrients to produce and develop new eggs, for their next generation. The female sucks up the blood of its victim, and any malady that the victim has flowing in its blood stream, will be injected into the mosquito's next victim thus spreading that malady.

A mosquito can ingest the blood of the healthiest person on the planet and cope quite happily, it does not need infected blood. So the mosquito can carry malaria parasites, that it has no use for, but the parasite has evolved to reproduce using this insect as a vector contributing to part of its life cycle.

The parasites invade the red blood cells making them burst, causing fever, fits, diarrhoea, shock, and jaundice. Drugs can treat and prevent the disease, but malaria remains a major cause of death and ill health in the tropics.

Malaria is also found in apes, monkeys, rats, birds, and reptiles. It is caused by various species of protozoa, a one-celled organism - called Sporozoans, that belong to the genus Plasmodium. These parasites are transmitted to humans by the bite of various species of mosquitoes belonging to the genus Anopheles.

Parasite   -   An organism living in or on another organism of a different species, called the host, from which it obtains food and protection. Many parasites have complex life cycles, with one or more intermediate hosts, of different species, supporting them during their development. The study of parasites - parasitology - is of importance in medicine since many parasites, such as bacteria, fungi, either cause or transmit disease. Many plants are either partly or completely parasitic.

MOSQUITOES - There are approximately 3,500 species of mosquitoes grouped into 41 different genera. Human malaria is transmitted only by the females of the genus or type  Anopheles. Of the approximately 430 Anopheles species, perhaps up to 60 types actually transmit malaria, that is, are vectors of the disease.

  Culex Pipiens  

 The Mosquito 

 Malaria 

  Plasmodium falciparum  

MALARIA - A serious, acute and chronic relapsing infection in humans, characterized by periodic attacks of chills and fever, anemia, enlargement of the spleen - splenomegaly, and often fatal complications. Malaria also is found in apes, monkeys, rats, birds, and reptiles. It is caused by various species of protozoa, a one-celled organism - called Sporozoans, that belong to the genus Plasmodium. These parasites are transmitted to humans by the bite of various species of mosquitoes belonging to the genus Anopheles .

Malaria is one of the most ancient infections known. It was noted in some of the West's earliest medical records in the 5th century BC, when Hippocrates differentiated Malarial fevers into three types according to their time cycles. It is not known when Malaria first made its appearance in the Americas, but it is highly probable that it was a post-Columbian importation; some rather severe epidemics were first noted in 1493.

The association between swampy or marshy areas and the disease has long been recognized, but the roles of the mosquito and of the Malarial parasite were not known until the beginning of the 20th century. In 1880 the French army surgeon Alphonse Laveran became the first person to describe the Malarial parasite and to recognize it as the cause of Malaria. In 1897–98 the British physician Sir Ronald Ross proved that bird Malaria is transmitted by Culex mosquitoes, and he described the entire life cycle of that parasite in the mosquito. In 1898 the Italian investigators Amico Bignami, Giovanni Battista Grassi, and Giuseppe Bastianelli first infected humans with Malaria by mosquitoes, described the full development of the parasite in humans, and noted that human Malaria is transmitted only by anopheline mosquitoes. The disease can also be transmitted unnaturally by common use of the hypodermic needle, as among drug addicts, or occasionally by blood transfusion from infected donors.

Malaria occurs throughout the tropical and subtropical regions of the world and is the most prevalent of all serious infectious diseases. In the late 20th century, annual cases worldwide were estimated at 250 million, with 2 million deaths resulting. Incomplete or faulty reports from Africa make even those rough estimates unreliable, however. Though Malaria can occur in temperate regions, it is most common in the tropics and subtropics, where climatic conditions are favorable for the mosquitoes that transmit the disease throughout the year. In many parts of sub-Saharan Africa, entire human populations are infected more or less constantly. Malaria is also common in Central America, the northern half of South America, and in South and Southeast Asia. The disease also occurs in countries bordering on the Mediterranean, in the Middle East, and in East Asia.

Anopheline mosquitoes are the only known vectors of Malaria in humans, and about 60 different species perform this function throughout the world. These mosquitoes undergo an aquatic larval stage, pupate, and then hatch into flying adults. The females require a meal of blood to produce fertile eggs, and females of some species prefer human to animal blood. The female mosquito ingests the Malarial parasite by biting a human already infected with the parasite.

The Malarial parasite has a complicated double life cycle, with a sexual reproductive cycle while it lives in the mosquito and an asexual reproductive cycle while in the human host. While in its asexual, free-swimming stage, when it is known as a sporozoite, the Malarial parasite is injected into the human bloodstream by a mosquito, passing through the skin along with the latter's saliva. The sporozoite eventually enters a red blood cell of its human host, where it goes through ring-shaped and amoeba-like forms before fissioning - dividing, into smaller forms called merozoites. The red blood cell containing these merozoites then ruptures, releasing them into the bloodstream,  causing the chills and fever that are typical symptoms of the disease. The merozoites can then infect other red blood cells, and their cycle of development is repeated.

A small proportion of the merozoites, however, become gametocytes, or germ cells, and can go through a sexual reproductive cycle once back in a mosquito. After they have been ingested by a mosquito from an infected human host, the separate male and female gametocytes pair off while in the mosquito's stomach and unite to form a single-celled zygote, which grows to become an oocyst. This oocyst eventually divides, releasing a multitude of asexual, free-swimming sporozoites that migrate to the mosquito's head and salivary glands, where they are ready to pass into the human bloodstream during the mosquito's next bite. The entire asexual cycle is then repeated.

A remarkable feature of the asexual cycle is that the parasites grow and divide synchronously, and the resulting mass fissions, into merozoites, produce the regularly recurring attacks, or paroxysms, that are typical of Malaria. A Malarial attack normally lasts 4 to 10 hours and consists successively of a stage of shaking and chills; a stage of fever, with the temperature reaching 105° F, and severe headache; and then a stage of profuse sweating during which the temperature drops back to normal. Between attacks, the temperature may be normal or below normal. In the early days of the infection, the attacks may occur every day, but they soon begin appearing at regular intervals of either 48 hours - called tertian Malaria or 72 hours - called quartan Malaria. The first attack usually occurs from 8 to 25 days after a person has been bitten by an infected mosquito.

Four species of Plasmodium are known to cause Malaria in humans: P. falciparum, P. vivax, P. Malariae, and P. ovale . The most common of these Malarial types, accounting for about 50 percent of all cases, is falciparum - subtertian, or malignant tertian - Malaria, which has the most severe symptoms and is the most frequently fatal; it accounts for as many as 95 percent of all deaths from Malaria. Falciparum Malaria requires higher temperatures for optimal development and is confined more closely to the tropical areas. In western Africa, for example, it exists almost to the exclusion of the other varieties. Once a person has recovered from falciparum Malaria, however, relapses rarely if ever occur. Vivax - tertian) - Malaria accounts for about 40 percent of all cases and is widespread mainly because of its ability to withstand therapy and to recur frequently for a period of several years, though the initial acute phase lasts only two to three weeks. The two less common types of Malaria are quartan Malaria - caused by P. Malariae, which is confined to the Mediterranean area, and ovale tertian Malaria - caused by P. ovale, which is basically confined to an isolated area of eastern Africa. Infections with one or more species can occur simultaneously, however. Furthermore, a double brood of tertian parasites can segment on alternate days, giving a daily or quotidian fever.

Besides attacks, persons with Malaria commonly suffer from anaemia - owing to the destruction of red blood cells by the parasites, enlargement of the spleen, the organ responsible for ridding the body of degenerate red blood cells, and general weakness and debility. 

In falciparum Malaria, the parasitized blood cells tend to stick together, and some of the smaller blood vessels may be blocked as a result. Falciparum Malaria may also cause other complications, such as Blackwater Fever (q.v.).

Malaria can be reliably diagnosed upon finding the parasites in stained blood smears examined under a microscope. An effective treatment for Malaria was known long before the cause of the disease was understood: the bark of the cinchona tree, whose most active principle, quinine, was used to alleviate Malarial fevers from 1700 until World War II, when more effective, synthetic drugs were developed. Chief among these newer drugs are chloroquine, pamaquine, pyrimethamine, and amodiaquin, all of which can destroy the Malarial parasites while they are living inside red blood cells. In their initial decades of use, chloroquine and related drugs could relieve symptoms of an attack that had already started, prevent attacks altogether, and even wipe out the plasmodial infection entirely. By the late 20th century, however, some vivax strains as well as most falciparum strains had become resistant to the drugs, which were thus rendered ineffective. As a result, the incidence of Malaria began to increase after having steadily declined for decades. Both one's natural resistance, as occurs among those who are carriers of one gene for the sickle-cell trait, and one's acquired immunity through previous exposure will reduce susceptibility to Malaria.

The basic method of prevention is to eliminate the breeding places of Anopheles mosquitoes by draining and filling marshes, swamps, stagnant pools, and other large or small bodies of standing fresh water. DDT, dieldrin, and other, less toxic insecticides have proved potent in controlling mosquito populations in affected areas. Window screens and mosquito netting are widely used to secure interior spaces from the mosquitoes, which are mainly active at night.

Mosquito A small flying insect that could be described as a type of Fly. It lives worldwide, especially in the tropics. It has long legs and a slender abdomen, Culex Forma. In most species the males feed on plant juices, while the females suck the blood of mammals, quite often transmitting serious diseases, including malaria and yellow fever. The mosquito is not strictly a parasite.

There are around 3,500 different species of mosquito throughout the world, of which 150 kinds live in the United States of America. One female can lay over 200 eggs at a time, and these mosquito eggs can survive for more than five years, lying in stasis waiting for a sufficient amount of water to trigger life. Every mosquito need water to complete the first three stages of it's life-cycle. 

Not all species want to bite humans; some prefer birds, others prefer horses, and some will even bite frogs and turtles, but like the flea they will go off specie, when survival depends on it. Only the females take blood, the males either never feed or only on plant nectar. When they bite though they can kill.

Size for size, the mosquito can fly extensive distances and whilst some of the genus remain close to their place of birth, others can fly 20 miles or more. In human terms this like around the world twice. 

Mosquitoes do not live in grass or shrubbery, their main habitat is the air, although some adults rest in these areas during daylight hours, during the night depending on personal liking . Around 2.5 Million people die each year worldwide. There are even 2,000 cases of Malaria reported in the UK, from travelers and mozzies who have flown in on a jet-plane.  Mosquitoes are directly responsible for more human deaths and illnesses than any other living creature. Historically it has been calculated, they are also a clear leader. Depending on how you wish to go back in the time of the human species, the mosquito has killed over FIVE BILLION PEOPLE.

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