Malaria resistance in the external environment. Modern treatment and prevention of malaria

an infectious disease caused by several species of protozoa of the genus Plasrnodium, transmitted by mosquitoes of the genus Anopheles, characterized by febrile paroxysms, hypochromic anemia, enlarged spleen and liver.

Bromeliad malaria- a nosogeographical variant of M., epidemiologically not associated with the presence of reservoirs, since its carrier is the Anopheles mosquito species that nest in bromeliad plants in South and Central America.

Congenital malaria(m. congenka) - M. in newborns, occurring when infected through a pathologically altered placenta or during

Hyperendemic malaria- M., registered in an area characterized by a high prevalence of the population: splenic in children 2-9 years old constantly exceeds 50% and is high in the adult population.

Hypoendemic malaria- M., registered in an area characterized by a low prevalence of the population: the splenic malaria index in children 2-9 years old does not exceed 10%.

Holoendemic malaria- M., registered in an area characterized by a very high prevalence of the population: the splenic malaria index in infants constantly exceeds 75%.

Mesoendemic malaria- M., registered in an area characterized by average degree prevalence of the population: the splenic malaria index in children 2-9 years old is in the range of 11-50%.

Malaria “unstable”- M., epidemiologically characterized by significant fluctuations in the prevalence of the population both during the infection transmission zone and from year to year, as well as, as a rule, low collective immunity to M.

Malaria oval(m. ovale) - a clinical form of M., caused by Plasmodium ovale and characterized by regular paroxysms that occur after 48 hours in the evening or at night; has a mild flow.

Pernicious malaria(m. perniciosa) is the general name for severe forms of tropical M.

Malaria mixed(m. mixta) - M. resulting from infection of the same person with two or more types of malaria pathogen.

Malaria “persistent”(m. stabilis) - M., epidemiologically characterized by a stable level of infestation of the population without significant fluctuations over a number of years and, as a rule, pronounced collective immunity to M.

Malaria is a disease of the African continent, South America and South-East Asia. Most cases of infection occur in young children living in West and Central Africa. In these countries, malaria leads among all infectious pathologies and is the main cause of disability and mortality in the population.

Etiology

Malaria mosquitoes are ubiquitous. They breed in stagnant, well-warmed bodies of water, where favorable conditions remain - high humidity and heat air. That is why malaria was previously called “swamp fever.” Malaria mosquitoes differ in appearance from other mosquitoes: they are slightly larger, have darker colors and transverse white stripes on their legs. Their bites also differ from ordinary mosquitoes: malaria mosquitoes bite more painfully, the bitten area swells and itches.

Pathogenesis

There are 2 phases in the development of Plasmodium: sporogony in the mosquito body and schizogony in the human body.

In more rare cases, this occurs:

1. Transplacental route - from a sick mother to a child,
2. Blood transfusion route - during blood transfusion,
3. Infection through contaminated medical instruments.

The infection is characterized by high susceptibility. Residents of the equatorial and subequatorial zones are most susceptible to malaria infection. Malaria is the leading cause of death among young children living in endemic regions.

malaria regions

The incidence is usually recorded in the autumn-summer period, and in hot countries - throughout the year. This is an anthroponosis: only people get sick from malaria.

Immunity after an infection is unstable and type-specific.

Clinic

Malaria has an acute onset and is characterized by fever, chills, malaise, weakness and headache. rises suddenly, the patient shakes. Later, dyspepsia and pain syndromes which are manifested by pain in muscles and joints, nausea, vomiting, diarrhea, hepatosplenomegaly, and convulsions.

Types of malaria

Three-day malaria is characterized by paroxysmal course. The attack lasts 10-12 hours and is conventionally divided into 3 stages: chills, fever and apyrexia.

During the interictal period, body temperature normalizes, patients experience fatigue, weakness, and weakness. The spleen and liver become denser, the skin and sclera become subicteric. IN general analysis blood reveals erythropenia, anemia, leukopenia, thrombocytopenia. During attacks of malaria, all systems of the body suffer: reproductive, excretory, hematopoietic.

The disease is characterized by a long-term benign course, attacks are repeated every other day.

In children, malaria is very severe. The pathology clinic for children under 5 years of age is unique. Atypical attacks of fever occur without chills and sweating. The child turns pale, his limbs become cold, general cyanosis, convulsions, and vomiting appear. At the beginning of the disease, the body temperature reaches high numbers, and then a persistent low-grade fever persists. Intoxication is often accompanied by severe dyspepsia: diarrhea, abdominal pain. Sick children develop anemia and hepatosplenomegaly, and a hemorrhagic or macular rash appears on the skin.

Tropical malaria is much more severe. The disease is characterized by less severe chills and sweating, but longer bouts of fever with an irregular fever curve. During a drop in body temperature, chilling occurs again, a second rise and a critical decline. Against the background of severe intoxication, patients develop cerebral signs - headache, confusion, convulsions, insomnia, delirium, malarial coma, collapse. Possible development of toxic hepatitis, respiratory and renal pathology with corresponding symptoms. In children, malaria has everything character traits: febrile paroxysms, special character of fever, hepatosplenomegaly.

Diagnostics

Diagnosis of malaria is based on the characteristic clinical picture and epidemiological data.

Laboratory research methods occupy a leading place in the diagnosis of malaria. Microscopic examination of a patient's blood allows one to determine the number of microbes, as well as their type and type. For this, two types of smears are prepared - thin and thick. A thick drop of blood is examined if malaria is suspected, to identify Plasmodium and determine its sensitivity to antimalarial drugs. The type of pathogen and the stage of its development can be determined by examining a thin drop of blood.

In a general blood test in patients with malaria, they detect hypochromic anemia, leukocytosis, thrombocytopenia; in a general urine test - hemoglobinuria, hematuria.

Fast, reliable and reliable method laboratory diagnostics malaria is PCR. This expensive method is not used for screening, but only as an addition to the main diagnosis.

Serodiagnosis is of auxiliary value. Lead linked immunosorbent assay, during which the presence of specific antibodies in the patient’s blood is determined.

Treatment

All patients with malaria are hospitalized in an infectious diseases hospital.

Etiotropic treatment of malaria: "Hingamin", "Quinine", "Chloridine", "Chloroquine", "Akrikhin", sulfonamides, antibiotics - "Tetracycline", "Doxycycline".

In addition to etiotropic therapy, symptomatic and pathogenetic treatment is carried out, including detoxification measures, restoration of microcirculation, decongestant therapy, and the fight against hypoxia.

Colloidal, crystalloid, complex salt solutions are administered intravenously,"Reopoliglyukin", isotonic saline, "Hemodez". Patients are prescribed Furosemide, Mannitol, Eufillin, and undergo oxygen therapy, hemosorption, and hemodialysis.

To treat complications of malaria, glucocorticosteroids are used - intravenous Prednisolone, Dexamethasone. According to indications, plasma or red blood cells are transfused.

Patients with malaria should strengthen their immunity. IN daily diet It is recommended to add nuts, dried fruits, oranges, lemons. During illness, it is necessary to exclude the consumption of “heavy” foods, and give preference better than soups, vegetable salads, cereals. You should drink as much as possible more water. It lowers body temperature and removes toxins from the patient's body.

Persons who have had malaria are monitored by an infectious disease specialist and undergo periodic examinations for plasmodium carriage for 2 years.

Folk remedies will help speed up the healing process:

Timely diagnosis and specific therapy shorten the duration of the disease and prevent the development of severe complications.

Prevention

Preventive measures include timely identification and treatment of patients with malaria and carriers of malarial plasmodium, conducting epidemiological surveillance of endemic regions, extermination of mosquitoes and the use of remedies for their bites.

A vaccine against malaria has not yet been developed. Specific prevention malaria is the use of antimalarial drugs. Persons traveling to endemic areas must undergo a course of chemoprophylaxis with Hingamin, Amodiaquine, and Chloridine. For greatest effectiveness, it is recommended to alternate these drugs every month.

You can protect yourself from mosquito bites by using natural or synthetic repellents. They are collective and individual and are available in the form of spray, cream, gel, pencils, candles and spirals.

Mosquitoes are afraid of the smell of tomatoes, valerian, tobacco, basil oil, anise, cedar and eucalyptus. Add a couple of drops of essential oil to vegetable oil and apply it to open areas bodies.

Video: life cycle of falciparum plasmodium

Malaria (Febris inermittens) is a group of protozoan vector-borne human diseases, the causative agents of which are transmitted by mosquitoes of the genus Anopheles. Characterized by predominant defeat reticulohistiocytic system and red blood cells, manifested by febrile paroxysms, anemia and hepato-splenomegaly. May cause relapses.

The causative agents of malaria are unicellular microorganisms belonging to the phylum Protozoa, class Sporozoa, order Haemosporidea, family Plasmodi, genus Plasinodium. More than 60 species of Plasmodium are known.

Human malaria is caused by 4 types of pathogen:

1) Pl. falciparum - the causative agent of tropical malaria,

2) Pl. Vivax - the causative agent of three-day vivax malaria,

3) Pl. ovale - causative agent of oval malaria,

Types of malarial plasmodia consist of separate geographical varieties or strains that differ in biological and immunological properties and sensitivity to drugs. For example, African strains of Pl. falciparum cause more severe forms of malaria than Indian malaria.

In the population of “northern” strains of Pl. vivax is dominated by bradysporozoites, infection with which leads to the development of the disease after prolonged incubation. Among the “southern” strains, on the contrary, tachysporozoites predominate. For this reason, infection with “southern” strains causes illness after a short incubation, often followed by the development of late relapses. When infected with strains of the "Chesson" group, which are characterized by very high heterogeneity in terms of the duration of exoerythrocytic development, the diseases occur with frequent relapses occurring at different times. A certain heterogeneity in the duration of exoerythrocyte development in Pl is assumed. falciparum. However, due to the short duration of the delay in exoerythrocyte development in Pl. falciparum in tropical malaria, secondary latency is not observed.

During the process of erythrocyte schizogony, some merozoites differentiate into male and female germ cells. Duration of development of gametocytes of all types of malaria pathogens, except Pl. falciparum, only a few hours exceeds the development time of asexual forms. A few hours after maturation, such gametocytes die. At Pl. falciparum mature gametocytes appear in peripheral blood approximately 12 days after the penetration of merozoites into erythrocytes. Some of the gametocytes may remain viable and infectious to mosquitoes for several weeks.

The potential for malaria to spread is determined by the length of the transmission season. When the number of days per year with air temperatures above 15°C is less than 30, the spread of malaria is impossible; if there are from 30 to 90 such days, the possibility is assessed as low, and if there are more than 150, then the possibility of spread is very high (if there are mosquito vectors and a source infections). Carries Plasmodium different kinds(over 50) mosquitoes from the genus Anopheles. A person becomes infected when they are bitten by an infected mosquito, or through a blood transfusion from a person with malaria. Intrauterine infection of the fetus is possible. A mosquito becomes infected from a sick person from the period when mature gamonts appear in the blood. With three- and four-day malaria, this is possible after the second or third attack, with tropical malaria - after the 7-10th day of illness.

Pathogenesis of malaria

Adrenal insufficiency, microcirculation disorders, cellular respiration can lead to acute renal failure - “shock kidney”. In acute attacks of malaria, due to impaired tissue respiration and changes in adenyl cyclase activity, the development of enteritis is also possible.

During the first attacks of malaria, the spleen and liver enlarge due to acute blood supply and a significant increase in the reaction of the RES of these organs to the breakdown products of erythrocytes and Plasmodium toxins. With a large amount of hemomelanin in the liver and spleen, endothelial hyperplasia occurs, and with a long course of the disease, connective tissue grows, which is expressed in the induration of these organs.

Nephrotic syndrome in quartan malaria is one of the conditions associated with deposits of soluble malarial immune complexes on the glomerular basement membrane. In kidney biopsies from patients with nephrotic syndrome detect deposits on the basement membrane of the renal glomeruli of immunoglobulins in the form of coarse granules consisting of IgG, IgM and complement.

Malaria is especially severe in individuals with underweight due to dehydration, overheating, with concomitant anemia, when combined with typhoid fever, viral hepatitis, amoebiasis and some other infections.

Symptoms of malaria

• Three-day malaria

The pathogen has the ability to cause disease after short (10-21 days) and long (6-13 months) incubation, depending on the type of sporozoite. Three-day malaria is characterized by a long-term benign course. Repeated attacks (distant relapses) occur after a latent period of several months (3-6-14) and even 3-4 years. IN in some cases In non-immune individuals, malaria can be severe and fatal.

In non-immune individuals who become ill for the first time, the disease begins with a prodrome: malaise, weakness, headache, aches in the back and limbs. In most cases, typical attacks of malaria are preceded by a 2-3-day increase in body temperature to 38-39 ° C of the wrong type. Subsequently, attacks of malaria are clinically clearly defined, occurring at regular intervals and more often at the same time of day (between 11 a.m. and 3 p.m.). In moderate to severe cases of the disease, during chills the patient experiences severe weakness, a sharp headache, aching pain in large joints and the lower back, rapid breathing, and repeated vomiting. Patients feel tremendous chills and cold. The face turns pale. Body temperature quickly reaches 38-40°C. After the chill, the fever begins. The face turns red, the skin of the body becomes hot. Patients complain of headache, thirst, nausea, and tachycardia increases. Blood pressure decreases to 105/50-90/40 mm Hg. Art., dry wheezing is heard above the lungs, indicating the development of bronchitis. Almost all patients experience moderate bloating and loose stools. The duration of chills is from 20 to 60 minutes, heat - from 2 to 4 hours. Then the body temperature decreases and reaches normal levels after 3-4 hours. During this period, sweating increases. Feverish attacks last from 5 to 8 hours. The interictal period lasts about 40-43 hours. Enlargement of the liver and spleen can be detected already in the first week of the disease. Anemia develops gradually. In the natural course of the disease in untreated cases, febrile attacks last 4-5 weeks. Early relapses usually occur 6-8 weeks after the end of the initial fever and begin with regularly alternating paroxysms; prodromal phenomena are not typical for them.

Complications from three-day malaria are rare. In people with underweight due to overheating and dehydration severe course malaria may be complicated by endotoxic shock. Combinations of malaria with severe forms of other infections or diseases can be fatal.

• Tropical malaria

Incubation period about 10 days with fluctuations from 8 to 16 days. Tropical malaria in non-immune individuals is characterized by the greatest severity and often acquires a malignant course. Without antimalarial drugs, death can occur in the first days of illness. Some people who become sick with malaria for the first time experience prodromal phenomena - general malaise, increased sweating, loss of appetite, nausea, loose stools, two to three days of increased body temperature to 38°C. In most non-immune individuals, the onset of the disease is sudden and characterized by mild chills, high fever, agitation of patients, severe headache, aches in muscles and joints. Fever for the first 3-8 days permanent type, then takes on a stable intermittent character. At the height of the disease, attacks of fever have some characteristics. There is no strict frequency for the onset of fever attacks. They can begin at any time of the day, but most often occur in the first half of the day. A decrease in body temperature is not accompanied by sudden sweating. Feverish attacks last more than a day (about 30 hours), periods of apyrexia are short (less than a day).

During periods of chills and heat, the skin is dry. Characterized by tachycardia and a significant decrease in blood pressure to 90/50-80/40 mm Hg. Art. The respiratory rate increases, a dry cough, dry and moist wheezing appear, indicating the development of bronchitis or bronchopneumonia. Often develop dyspeptic symptoms: anorexia, nausea, vomiting, diffuse epigastric pain, enteritis, enterocolitis. The spleen enlarges from the first days of the disease, which is manifested by pain in the left hypochondrium, increasing with deep breath. By the 8-10th day of illness, it is easily palpable, its edge is dense, smooth, and painful. Often develops toxic hepatitis, however, liver functions are slightly impaired. In the blood serum, the content of direct and indirect bilirubin increases, the activity of aminotransferases increases moderately - only 2-3 times. Renal dysfunction in the form of mild toxic nephrosonephritis is observed in 1/4 of patients. From the first days of the disease, normocytic anemia is detected. On the 10-14th day of illness, the hemoglobin content usually decreases to 70-90 g/l, and the number of erythrocytes to 2.5-3.5o1012/l. Leukopenia with neutropenia, relative lymphocytosis and a nuclear shift towards young forms of neutrophils are noted, reticulocytosis and ESR increase. Plasmodium in the ring stage is detected in the peripheral blood from the first days.

• Quartan

• Ovale malaria

Endemic to West African countries. The incubation period is from 11 to 16 days. This form of malaria is characterized by a benign course and frequent spontaneous recovery after a series of attacks of primary malaria. The clinical manifestations of oval malaria are similar to tertian malaria. A distinctive feature is the onset of attacks in the evening and night hours. The duration of the disease is about 2 years, however, relapses of the disease have been described that occurred after 3-4 years.

Complications of malaria

The greatest danger is malignant forms malaria: cerebral (malarial coma), infectious toxic shock(algic form), severe form of hemoglobinuric fever.

• Cerebral form occurs more often in the first 24-43 hours from the onset of the disease, especially in people with underweight. Harbingers of malarial coma are severe headache, severe weakness, apathy or, conversely, anxiety, fussiness. In the precomatous period, patients are inactive, answer questions monosyllabically and reluctantly, quickly become exhausted and again plunge into a soporotic state.

During examination, the patient's head is thrown back. The legs are often in an extension position, the arms are bent at the elbow joints. The patient has severe meningeal symptoms (stiff neck, Kernig's and Brudzinski's symptoms). These symptoms in malarial coma are caused not only by cerebral hypertension, but are also associated with damage to the tonic centers in the frontal region. Hemorrhages in the lining of the brain cannot be ruled out. In some patients, phenomena of hyperkinesis are observed from clonic muscle spasms of the limbs to general tetanic or epileptiform seizures. At the beginning of coma, the pharyngeal reflex disappears, later the corneal and pupillary reflexes.

When examining the patient, the body temperature was 38.5-40.5°C. Heart sounds are muffled, pulse rate corresponds to body temperature, blood pressure is reduced. Breathing is shallow, rapid from 30 to 50 times per minute. The liver and spleen are enlarged and dense. Function is impaired pelvic organs, as a result of which appear involuntary urination and defecation. In the peripheral blood, in half of the patients there is an increase in the number of leukocytes to 12-16o109/l with a nuclear shift towards young forms of neutrophils.

• For infectious-toxic shock (algic form of malaria) severe weakness and lethargy develop, turning into prostration. The skin is pale gray, cold, covered with sweat. The facial features are pointed, the eyes are deeply sunken with blue circles, the gaze is indifferent. Body temperature is reduced. The distal parts of the limbs are cyanotic. Pulse more than 100 beats/min, low filling. Maximum blood pressure drops below 80 mm Hg. Art. Breathing is shallow, more than 30 times per minute. Diuresis less than 500 ml per day. Sometimes there is diarrhea.

• Hemoglobinuric fever occurs more often after taking quinine or primaquine. Massive intravascular hemolysis can also be caused by other drugs (delagil, sulfonamides). The complication occurs suddenly and is manifested by stunning chills, hyperthermia (up to 40°C or more), aches in the muscles, joints, severe weakness, vomiting of dark bile, headache, unpleasant sensations in the upper abdomen and lower back. The main symptom of hemoglobinuria is the discharge of black urine, which is due to the content of oxyhemoglobin in freshly released urine, and methemoglobin in standing urine. When standing, urine is divided into two layers: the upper layer, which has a transparent dark red color, and the lower layer, which is dark brown, cloudy, and contains detritus. In urine sediment, as a rule, clumps of amorphous hemoglobin and single unchanged and leached red blood cells are found. The blood serum becomes dark red, anemia develops, and the hematocrit decreases. The content of free bilirubin increases. In the peripheral blood, neutrophilic leukocytosis with a shift towards younger forms, the number of reticulocytes increases. Most dangerous symptom is acute renal failure. Creatinine and urea levels quickly increase in the blood. The next day, the skin and mucous membranes become jaundiced, possibly hemorrhagic syndrome. In mild cases, hemoglobinuria lasts 3-7 days.

Treatment and prevention of malaria

Used to treat malaria various drugs, which can prevent attacks of malaria, quickly stop the symptoms of an attack that has begun, or completely destroy the pathogen. Among them, the most famous are chloroquine, quinine, mefloquine, primaquine and quinacrine hydrochloride, also sold under the names atabrine and quinine. People planning to travel or stay in areas where malaria is endemic are advised to take antimalarial drugs such as chloroquine regularly.

To treat acute manifestations of malaria, hematocides are prescribed.

If Pl.vivax, Pl.ovale, Pl.malariae are detected, drugs from the group of 4-aminoquinolines (chloroquine, nivaquin, amodiaquine, etc.) are prescribed. The most common drug chloroquine (Delagil) is prescribed according to the following regimen: on the 1st day, 10 mg/kg base (first dose) and 5 mg/kg base (second dose) with an interval of 6 hours, on the 2nd and 3rd days – 5 mg/kg. A total of 25 mg/kg base per course. There are isolated reports of resistance of P./vivax strains to chloroquine in Burma, Indonesia, Papua New Guinea and Vanuatu. In these cases, treatment should be with quinine, mefloquine or fansidar.

Quinine sulfate is prescribed at a dose of 10 mg/kg, followed by taking the drug at the same dose after 8 hours, then 10 mg/kg once a day for 7-10 days. If taking quinine orally is not possible (for example, with repeated vomiting), the first dose of quinine is prescribed intravenously. If intravenous administration also impossible, carry out intramuscular injections quinine with precautions due to the risk of abscesses.

Mefloquine is prescribed once for adults at a dose of 15 mg/kg base, for children - in smaller doses. Mefloquine should not be given more than 12 hours after the last dose of quinine. Mefloquine tablets are recommended to be taken with big amount liquids. Women childbearing age should abstain from pregnancy using reliable contraception during the entire period of taking the drug, as well as for 2 months after taking its last dose.

Fansidar (1 tablet contains 25 mg of pyrimethamine and 500 mg of sulfadoxine) is taken once: adults - 3 tablets, children 8-14 years old - 1-2 tablets, 4-8 years old - 1 tablet, from 6 weeks to 4 years - 1/ 4 tablets. Fansidar also has a hamontotropic effect, i.e. affects the germ cells of the malarial plasmodium circulating in the blood.

To completely cure (prevent long-term relapses) from malaria caused by Pl.vivax or Pl.ovale, a tissue schizontocide, primaquine, is used at the end of the course of hematocidal drugs. The drug is prescribed for 14 days at a dose of 0.25 mg/kg base per day. Pl.vivax strains resistant to primaquine are found in the Pacific Islands and Southeast Asia. In these cases, it can be recommended to take primaquine at a dose of 0.25 mg/kg per day for 21 days. Taking primaquine can cause the development of intravascular hemolysis in patients with deficiency of the enzyme glucose-6-phosphate dehydrogenase (G-6-PD) of erythrocytes. Such patients, if necessary, can be prescribed an alternative treatment regimen with primaquine: 0.75 mg/kg per day once a week for 8 weeks. Primaquine also has a hamontotropic effect.

If Pl.falciparum is detected in a patient in cases where the course is not severe and there are no prognostically unfavorable indicators, the drugs of choice are mefloquine, fansidar and halofantrine.

Halofantrine is prescribed 3 times a day with an interval of 6 hours at a dose of 8 mg/kg per dose; the course of treatment is one day. In the absence of mefloquine and halofantrine, the presence of contraindications to them or identified resistance, quinine is prescribed in combination with antibiotics (tetracycline, doxycycline). Tetracycline is prescribed first at a dose of 1.5 mg/kg, after 6 hours 5 mg/kg, then for 7 days at 1.5 mg/kg per day. Doxycycline is prescribed at 1.5 mg/kg once for 7 days. Treatment with quinine tablets is carried out according to the same scheme as described above.

In the treatment of tropical malaria with a “malignant course” (severe course with the development of complications), quinine is used in the form of slow intravenous (over 4 hours) drip infusions. In these cases, it is recommended to begin treatment with a dose of quinine of 20 mg per 1 kg of body weight, and subsequently use a dose of 10 mg/kg. A 5% glucose solution is used as the injected liquid. The interval between intravenous drip infusions of quinine is 8 hours. The daily dose of quinine should not exceed 30 mg/kg. This therapy is carried out until the patient recovers from a serious condition, after which they switch to oral administration. If the patient develops acute renal failure, the daily dose of quinine is reduced to 10 mg/kg, due to the accumulation of the drug.

Patients with a malignant course of tropical malaria should be urgently hospitalized in specialized department, having equipment for hemodialysis. Treatment of complications of tropical malaria is carried out against the background of antimalarial therapy according to general principles.

Acute anthroponotic transmissible protozoonosis. Pathogens of malaria- unicellular animals (protozoa), belong to the class Sporozoa, subclass Coccidia, family Plasmodium, genus Plasmodium. The person knows 4 types of malaria pathogens:

Plasmodium vivax (p. vivax)- causative agent of three-day malaria;

Plasmodium malaria (p. malariae) - causative agent of four-day malaria;

Plasmodium falciparum (p. falciparum) - causative agent of tropical malaria;

Plasmodium oval (p. ovale)- the causative agent of a special form of tertian malaria.

The latter species is found naturally in Africa, Palestine, South America, in the Philippines. In Russia, the existence of the oval has not been established. A person under natural conditions can become infected with the causative agent of monkey malaria through mosquitoes.

2. Development cycle of malarial pathogens carried out with a change of owners:

Sexual development (sporogony) occurs in the body of the final host - a female mosquito of the genus Anopheles;

Asexual development (schizogony)- in the body of the intermediate host - humans).

3. Sporogony - male and female reproductive cells of plasmodia that enter the stomach of a mosquito with human blood (micro- and macrogametocytes) turn into mature micro- and macrogametes, which, after fertilization, go through a series of successive stages of development (from zygote to sporocyst) of invasive forms of sporozoites that accumulate in the salivary glands of the insect. The duration of sporogony is determined by the type of plasmodium and the ambient temperature. At optimal air temperature (25 °C), sporogony lasts 10 days for Plasmodium Vivax, 12 days for Falciparum, and 16 days for Malaria and Ovale. At air temperatures below 15 °C, sporozoites do not develop. Sporozoites undergo further development in the body of a vertebrate host, into which they penetrate through blood-sucking mosquitoes.

- in tissue cells - tissue schizogony;

In erythrocytes - erythrocyte schizogony.

In some strains pl. falciparum all stages of schizogony can be detected in peripheral blood in a significant proportion of patients and with relatively mild flow diseases.

Women's gamonts reach the stage of full maturity - the stage of gametes in human blood, male gametes mature in the body of the carrier. Upon completion of the maturation process in the stomach of the mosquito, the process of ejection of 4-8 male gametes by the male gametocyte is observed, which, after being released, actively move in the contents of the stomach and are able to penetrate the female gamete and fertilize it (sexual process). At pl. falciparum gametocytes first take on a round shape and only then microgametes are formed.

Fertilized female gametes(zygotes) penetrate the epithelium of the midgut (stomach) of the mosquito and form oocysts under its outer membrane. Oocysts grow and form big number sporozoites - mononuclear spindle-shaped formations (length 11-15 µm, width 1-1.5 µm).