Malaria is one of the most dangerous human diseases. Plasmodium parasites are transmitted to humans through the bites of infected Anopheles mosquitoes. Plasmodium vivax causes tertian malaria, Plasmodium malariae causes tertian malaria, Plasmodium ovale causes tertian malaria, and Plasmodium falciparum causes tropical malaria. Each form of the disease has its own characteristics, but symptoms of malaria such as fever attacks, anemia and hepatosplenomegaly are common to all.
The life cycle of the development of malarial plasmodium consists of 2 stages that occur in the body of the mosquito and the human body. In the human body, clinical manifestations of the disease are associated only with erythrocyte schizogony. Malaria is a polycyclic infection. During the course of the disease, there is an incubation period (primary and secondary), a period of primary acute manifestations, secondary latency and relapse period. If infection occurs naturally(via ), they talk about a sporozoite infection. If the disease develops when a donor's blood containing plasmodia is introduced into the human body or as a result of vaccination, they speak of schizont malaria.
Rice. 1. The malaria mosquito is a carrier of malarial plasmodia.
Rice. 2. Plasmodium parasites are the cause of malaria.
Incubation period
When a mosquito bites, sporozoites penetrate into the blood, where they move freely for 10 to 30 minutes, and then settle in hepatocytes (liver cells). Some sporozoites of Pl. ovale and Pl. vivax hibernate, another part of them and Pl. falciparum and Pl. malaria immediately begins hepatic (exoerythrocytic) schizogony, during which from 1 sporozoite is formed from 10 to 50 thousand hepatic merozoites. Having destroyed the liver cells, merozoites are released into the blood. The entire process lasts from 1 to 6 weeks. This ends the incubation period of malaria and begins the period of erythrocyte schizogony - the period of clinical manifestations.
Different types of pathogens have their own duration of the incubation period of malaria:
- With Plasmodium vivax, the short incubation period is 10 - 21 days, long incubation - 8 - 14 months.
- With Plasmodium malariae - 25 - 42 days (in some cases more).
- With Plasmodium falciparum - 7 - 16 days.
- For Plasmodium ovale - from 11 to 16 days.
The duration of the incubation period for malaria increases with inadequate chemotherapy.
Before an attack of malaria at the end of the incubation period with Plasmodium vivax and Plasmodium falciparum, a prodromal period is recorded: symptoms of intoxication and asthenia, headache, muscle and joint pain appear, general weakness, weakness, chilling.
Rice. 3. Malaria is common in more than 100 countries in Africa, Asia and South America.
Signs and symptoms of malaria during a febrile attack
Pathogenesis of fever in malaria
While in red blood cells, plasmodia absorb hemoglobin, but not completely. Its remains turn into dark brown pigment grains that accumulate in the cytoplasm of young schizonts.
When an erythrocyte ruptures, foreign proteins, hemoglobin, malarial pigment, potassium salts, and red blood cell residues enter the blood along with the merozoites. They are foreign to the body. By affecting the thermoregulation center, these substances cause a pyrogenic reaction.
Malaria in more cases occurs with characteristic febrile attacks. Rarely, the disease occurs with constant fever lasting from 6 to 8 days, and only then febrile paroxysms appear.
Rice. 4. Up to 30 thousand cases of “imported” malaria are registered annually, 3 thousand of which are fatal. In 2016, 100 cases of imported malaria were registered in the Russian Federation.
Development of a fever attack
- During the initial period of fever paroxysm The patient develops chills lasting from 30 minutes to 2–3 hours, often severe, the skin and mucous membranes become pale in color, and goose bumps appear. The patient is freezing and wraps himself in a blanket over his head.
Rice. 5. A rise in temperature during infectious diseases is always accompanied by chills.
- Feverish attack most often occurs around 11 am. Body temperature rises to 40°C or more, quickly, nausea, vomiting and dizziness occur. At severe course malaria causes convulsions, delirium and confusion. The patient is excited, the skin is hyperemic, hot and dry to the touch, and herpes rashes often appear on the lips. The tongue is coated with a brownish coating. There is tachycardia, shortness of breath and urinary retention, falling arterial pressure. The patient becomes hot. He is tormented by thirst.
Rice. 6. An attack of malaria in a woman (India).
- After 6 - 8 hours, and with tropical malaria towards the end first day, body temperature decreases. The patient develops profuse sweating. Symptoms of intoxication gradually disappear. The patient calms down and falls asleep. After half a day, the patient’s condition becomes satisfactory.
Rice. 7. A decrease in temperature is accompanied by profuse sweating.
- Repeated attacks of fever occur after 2 days for 3-day, oval and tropical malaria or after 3 days for 4-day malaria.
- Secondary latency period occurs after 10 - 12 attacks of fever.
- With inadequate treatment weeks (sometimes months) later, short-term (up to 3 months) or distant (6-9 months) relapses occur.
After several attacks, patients' liver and spleen enlarge, anemia develops, the cardiovascular and nervous systems suffer, symptoms of nephritis appear, and hematopoiesis suffers. After the cessation of febrile attacks, anemia and hepatosplenomegaly persist for quite a long time.
Rice. 8. Temperature curve for malaria.
Signs and symptoms of malaria affecting internal organs
Causes of damage to internal organs
In case of insufficient treatment various organs A patient with malaria exhibits pathological changes, the causes of which are:
- pathological substances circulating in the blood, leading to hyperplasia of the lymphoid and reticuloendothelial elements of the spleen and liver,
- sensitization of the body by foreign proteins, often accompanied by autoimmunopathological reactions of the hyperergic type,
- breakdown of red blood cells leading to damage internal organs, the development of anemia and thrombocytopenia, impaired blood circulation in the capillaries and the development of intravascular thrombus formation,
- disturbance of water-electrolyte balance.
Plasmodium, while in red blood cells, absorbs hemoglobin, but does not completely assimilate it. As a result, its remains gradually accumulate in the cytoplasm of young schizonts. When merozoites are formed, the pigment enters the blood and is then captured by liver macrophages, lymph nodes, spleen and bone marrow, which acquire a characteristic smoky or brown color. Over a long period of time, the pigment in the interstitial tissue forms massive accumulations. Its processing and disposal is slow. The specific coloring of the internal organs is preserved long time after healing.
Foreign substances circulating in the blood irritate the reticular cells of the spleen and liver, causing their hyperplasia, and over a long period of time - proliferation connective tissue. Increased blood supply to these organs leads to their enlargement and pain.
Lack of appetite, nausea and a feeling of fullness in the epigastric region, often diarrhea are the main signs of liver damage in malaria. The liver and spleen gradually begin to enlarge. By the 12th day, yellowness of the skin and sclera appears.
The liver and spleen are enlarged and dense in malaria. The spleen can rupture with minor trauma. Its weight often exceeds 1 kg, sometimes the weight reaches 5 - 6 kg or more.
Rice. 10. A liver specimen affected by plasmodia.
Rice. 11. Enlarged liver and spleen in patients with malaria.
Bone marrow damage
Anemia due to malaria
The breakdown of red blood cells during the period of erythrocyte schizogony, increased phagocytosis and hemolysis caused by the formation of autoantibodies are the main causes of anemia in malaria. The degree of anemia is influenced by the type of plasmodium. Iron deficiency and folic acid in residents of a number of developing countries in Africa, the disease worsens.
Gametocytes of plasmodium of 3-day, 4-day malaria and malaria oval develop in the erythrocytes of peripheral capillaries for 2 - 3 days and after maturation die after a few hours, therefore anemia in these types of malaria often reaches a significant degree. Blood regeneration slows down significantly during three-day malaria, since plasmodia settle mainly in young red blood cells - reticulocytes. In addition, Plasmodium vivax causes ineffective bone marrow erythropoiesis. Anemia due to malaria is exacerbated by the destruction of healthy (uninfected) red blood cells.
The degree of anemia is related to the size of the spleen. The spleen in the human body is the only blood filtering organ. Its increase is distinguishing feature malarial infections. When benign red blood cells are damaged in the spleen, extramedullary hematopoiesis starts to work, compensating for the losses.
Characteristic changes in the blood during malaria appear from 6 to 8 days of illness. And by the 12th day it is registered hypochromic anemia, significant leukopenia, thrombocytopenia, ESR significantly accelerates.
Rice. 12. Red blood cells become deformed when infected with Plasmodium vivax and Plasmodium ovale. When infected with Plasmodium malariae and Plasmodium falciparum, the shape and size of red blood cells do not change.
Rice. 13. Destruction of red blood cells when merozoites are released into the blood is one of the causes of anemia in the disease.
Signs and symptoms of malaria affecting the heart
The functioning of the heart is affected by toxic substances and anemia. Expansion of the borders of the heart to the left, muffled sounds at the apex and a slight systolic murmur at the apex are the first signs of organ damage in malaria. Long-term malaria has a negative impact on work of cardio-vascular system. The patient begins to experience swelling in the feet and legs.
Signs and symptoms of malaria affecting the nervous system
Malaria affects the autonomic nervous system. Irritability, headache, fast fatiguability- main symptoms of malaria when affected nervous system in long-term ill people.
Rice. 14. Brain damage due to malaria. Multiple hemorrhages are visible in the brain tissue.
Relapses of malaria
The cause of early relapses that occur during the first 3 months after the expected recovery is the surviving schizonts, which, when the immune system is weakened, actively reproduce again.
The course of relapses is usually benign. General toxic syndrome is moderately expressed. Malarial paroxysms occur rhythmically. Anemia, an enlarged spleen and liver are the main signs of recurrent malaria.
The duration of the disease caused by Plasmodium vivax lasts 1.5 - 3 years, Plasmodium ovale - from 1 to 4 years.
Rice. 15. Children with malaria.
Complications of malaria
Malaria causes complications that are closely related to the pathogenesis of the disease. These include severe anemia, persistent enlargement of the spleen and its cirrhosis, cirrhosis and melanosis of the liver, nephrosonephritis, encephalopathy with development mental disorders and hemoglobinuric fever.
At acute diffuse nephrosonephritis patients develop edema, protein and red blood cells in the urine, and in some cases develop arterial hypertension. Symptoms that are responsive to adequate treatment and diet.
At malarial hepatitis yellowness of the sclera and skin appears, the liver enlarges, its pain is noted on palpation, bilirubin in the blood increases, and liver function tests are distorted.
Available splenic rupture with minor injury.
Hemoglobinuric fever is the most severe complication of tropical malaria, rarely found in other types of disease. With the disease, acute hemolysis of red blood cells develops, a flood of hemoglobin in the blood and its excretion in the urine, which occurs under the influence of medicinal product quinine. The patient develops a jaundiced coloration of the sclera and skin, and the liver and spleen become enlarged.
Acute pulmonary edema develops in tropical malaria. The trigger mechanism is an increase in vascular permeability as a result of exposure to toxins. The problem is aggravated by the increased introduction of fluid into the patient's body.
Hypoglycemia develops mainly in tropical malaria. Its cause is a violation of glucogenesis in the liver, an increase in glucose consumption by plasmodia and stimulation of insulin secretion by the pancreas. When there is a disease, it accumulates in the patient’s tissues. a large number of lactic acid. Developed acidosis is often the cause of death.
Timely detection and adequate treatment malaria always ends in recovery. With late detection and inadequate treatment, tropical malaria is always fatal. The other three types of malaria are benign infections.
Rice. 17. Yellowness of the sclera and skin speaks of liver damage
Malaria in pregnant women
Malaria adversely affects the course of pregnancy and its outcome. It can cause abortion, miscarriage and premature birth. Fetal developmental delay and death are often observed. Malaria is often the cause of eclampsia in pregnant women and death. Pregnant women living in areas where malaria is endemic are the most endangered population. Late diagnosis and inadequate treatment quickly lead to the development of “malignant malaria”. The development of hypoglycemia is especially dangerous in pregnant women, which often causes death.
Rice. 18. Placenta infected with malarial plasmoids.
Malaria in children
The most vulnerable age is children from 6 months to 4 - 5 years. Malaria is especially dangerous for young children.
In malaria-endemic regions, the disease in children is one of the causes of high mortality. Children under 6 months of age born from immune mothers do not develop malaria.
Types of malaria in children
Malaria in children can be congenital or acquired.
Malaria in children often develops a fulminant course. Severe anemia may develop within a few days and cerebral form diseases. Malaria in children often occurs in a peculiar way:
- the skin is pale, often with an earthy tint, yellowness and waxiness persist for a long time, despite treatment;
- malarial paroxysms (fever attacks) are often absent;
- symptoms such as cramps, diarrhea, regurgitation, vomiting and abdominal pain come to the fore;
- during attacks of malaria there are often no chills at first, and at the end of an attack of fever there is often no sweating;
- a rash in the form of hemorrhages and spotty elements often appears on the skin;
- anemia increases quickly;
- with congenital malaria, the spleen is significantly enlarged, the liver - to a lesser extent.
Symptoms of malaria in older children
In older children, the disease progresses as in adults. During the interictal period, the children's condition remains satisfactory. Lightning form Three-day malaria is rare, and malarial coma is extremely rare.
Differential diagnosis
Malaria in children should be distinguished from hemolytic disease newborns, sepsis, septic endocarditis, miliary tuberculosis, pyelonephritis, hemolytic anemia, typhus, brucellosis, food poisoning, leishmaniasis in children living in the tropics.
Rice. 19. Up to 90% of malaria cases and deaths from it occur in countries of the African continent.
Rice. 20. About 1 million children die from malaria every year.
In addition, this disease can be transmitted from mother to fetus through contaminated blood transfusions and through contact with the blood of an infected person (for example, when drug addicts reuse syringes). Malaria is common in tropical areas, especially rural areas. It has reached epidemic levels in some countries, although the problem is less severe in cities.
Causes
Symptoms of malaria
The disease occurs cyclically. An attack of malaria usually lasts 6-10 hours and is manifested by a sharp increase in temperature to high numbers and successive periods of chills with trembling, heat and sweat. The end of the attack is characterized by a decrease in temperature to normal or subnormal levels and increased sweating, lasting 2-5 hours. Then comes deep dream. The attack is usually accompanied by headache and muscle pain, fatigue, weakness, nausea, etc. In some cases, there may be jaundice (yellowness of the skin and icterus of the sclera), coma.
The cycle is repeated every 48 or 72 hours.
Complications
Except very unpleasant symptoms The disease itself, malaria is very dangerous due to its complications:
Anemia
- liver damage, which may manifest as yellowing of the skin.
- lung damage with severe cough with bloody sputum.
- insufficiency.
- brain damage accompanied by seizures, loss of consciousness, paralysis or coma.
- hemoglobinuric fever, characterized by massive destruction of red blood cells and leading to acute form jaundice, hemoglobin excretion in urine, and renal failure.
What can you do
If you have visited an area known to have malaria or have recently had a blood transfusion and are experiencing symptoms similar to those described above, you should contact your doctor.
What can a doctor do?
Prevention of malaria
Avoid traveling to malarial areas. If you do travel to an epidemic area, ask your doctor or pharmacist about possible ways prevention. There are special antimalarial drugs. The course begins 1-2 weeks before the trip, continues during the entire stay in the epidemic zone and another four weeks upon return.
In addition, you need to protect yourself from mosquito bites. To do this, use repellents and mosquito nets.
Almost 100 countries with tropical and subtropical climates consider malaria to be the most serious health problem. The disease poses a danger both to residents of endemic risk zones and to tourists who come on vacation to hot countries.
What kind of disease is this
The most frequently reported cases of infection are in Africa, South-East Asia, Eastern Mediterranean. Any of these regions is dangerous for people with immunodeficiency, the elderly, pregnant women, children early age. All of them suffer from a severe form of the disease, and due to malaria they face increased risk death, miscarriage, stillbirth.
The causative agent of the disease is a simple unicellular organism of the genus Plasmodium. It comes in 4 types. In this regard, experts distinguish 4 forms of the disease:
- Ovale malaria. It's relative rare disease. It is found in West Africa. Oval malaria accounts for about 1% of cases. The causative agent is Plasmodium ovale.
- Four-day form. It is considered rare (up to 7% of cases). It is caused by Plasmodium malariae.
- Three-day form. It is caused by Plasmodium vivax. The disease caused by this pathogen is widespread in the world (up to 43% of cases).
- Tropical malaria. This form is the most common (up to 50% of cases). Its causative agent is Plasmodium falciparum.
How is malaria transmitted?
The disease can occur in almost any person living or who has visited endemic risk areas. There are just a few features:
- indigenous people of West Africa exhibit congenital immunity to Plasmodium vivax;
- People with sickle cell anemia easily tolerate the tropical form of the disease, which is considered the most dangerous, rapidly progressing if left untreated.
Malaria is caused by female Anopheles mosquitoes. They act as carriers of plasmodia. Insects transmit pathogens from sick people to healthy people through bites. In the past, several isolated cases of human infection with zoonotic species of Plasmodium (Plasmodium knowlesi and Plasmodium cynomolgi) have been recorded. These pathogens were transmitted to humans by mosquitoes after being bitten by sick monkeys.
With malaria, the incubation period depends on the type of plasmodium that has entered the body. The most rapid development of the disease is observed in the tropical form. The first symptoms appear after 8-16 days. The incubation period for the four-day form ranges from 3 to 6 weeks. Pathogens such as Plasmodium vivax and Plasmodium ovale are characterized by the preservation of dormant hypnozoites in the liver. The period from infection to activation can range from 6-8 months to 3 years.
First signs and main symptoms
Fever, chills, headache, muscle pain, muscle weakness, cough, vomiting, abdominal pain, diarrhea are possible Clinical signs. In the absence of treatment, negative progression of malaria is observed, the disease leads to manifestations of insufficiency individual organs(to acute renal failure, pulmonary edema). Coma and death may occur.
Of all the symptoms special attention deserves a fever. If it occurs for unknown reasons 7 days or more after the first possible contact with the pathogen, you should immediately consult a doctor. It is advisable to visit a specialist no later than 24 hours after the onset of symptoms indicating malaria, because treatment started in a timely manner will reduce or eliminate the likelihood of death.
An important feature of the disease is its paroxysmal course. In the first days, the fever is of the wrong type (temperature fluctuations are observed throughout the day without patterns). It lasts 1-3 days for three-day and oval malaria and 5-6 days for tropical malaria. After this period clinical picture takes the form of typical paroxysms (attacks). They clearly have 3 phases - chills, fever, sweating. The duration of attacks varies from 1-2 hours to 12 hours.
Paroxysms are repeated either after 48 hours (with tropical, three-day and oval malaria), or after 72 hours (with the four-day form of the disease). Between attacks, the condition of sick people is satisfactory. After 2-3 temperature paroxysms, the liver and spleen increase in size. Anemia develops from the second week of the disease.
Diagnosis and treatment
Medicine for malaria is prescribed after confirmation of the presence of the disease. Diagnosis includes anamnesis and clinical examination. Its obligatory part is laboratory methods. One of them is microscopic. During its use, blood products prepared by the “thin smear” and “thick drop” method and stained according to Romanovsky-Giemsa are examined. The microscopic method allows you to confirm or exclude the disease, determine the type of pathogen, and the severity of the infectious process.
After confirming the diagnosis, the doctor thinks about how to rid the patient of malaria. Treatment begins in a hospital setting. It includes:
- use of etiotropic drugs (Daraprim, Delagil, etc.);
- conducting pathogenetic therapy (prescribed drugs - Prednisolone, Corglicon, ascorbic acid, multivitamins).
Prognosis and prevention
The prognosis is favorable when timely diagnosis and treatment of uncomplicated malaria. Full recovery comes quickly. The most dangerous are malignant forms of the disease. The mortality rate caused by them is 1%. For example, in the cerebral (comatose) form, multiple hemorrhages are observed in the brain tissue, meninges. The disease is manifested by intense headache, nausea, repeated or repeated vomiting, disturbances and loss of consciousness. Death occurs due to increasing cardiac and respiratory failure.
It is possible to avoid the disease and its negative consequences, because malaria prevention has been developed. One of effective measures- use of drugs prescribed for treatment. It is recommended that you first consult with your doctor regarding such prophylaxis. Medicines are prescribed to those people who are going to travel to endemic areas. When drawing up a prevention plan, the specialist takes into account:
- malariological situation in the region, malaria season, period of disease transmission (part of the year during which pathogens can be transferred from mosquitoes to humans);
- planned duration of stay in the endemic territory;
- the presence of individual intolerance to drugs.
In order to reduce the likelihood of developing malaria, prevention also includes the use of drugs personal protection(mosquito nets, repellents). An important role is played by chemical, physical, biological and hydraulic measures carried out by countries at the state level (bringing water sources to proper sanitary and technical condition, leveling the banks, clearing vegetation, etc.). A vaccine is also being developed that could protect 100% from infection.
Malaria, formerly called "swamp fever" - group infectious diseases, caused by malarial plasmodia, which are transmitted to humans through bites by malaria mosquitoes (mosquitoes of the genus Anopheles). 85–90% of cases of the disease and mortality from it are recorded in the southern regions of Africa; in European territory, cases of malaria are mainly imported. More than 1 million cases of the disease are recorded annually, resulting in death.
Symptoms of malaria
In the blood, malarial plasmodium is fixed on erythrocytes.There are 4 forms of malaria caused by different types of pathogens: three-day, four-day, tropical and the so-called oval malaria. Each form of the disease has its own characteristics, but all have common symptoms: attacks of fever, enlarged spleen and anemia.
Malaria is a polycyclic infection; there are 4 periods during its course:
- incubation (primary latent);
- period of primary acute manifestations;
- latent secondary;
- relapse period.
The duration of the incubation period directly depends on the type of pathogen. At the end of it, so-called symptoms appear - harbingers of the disease: headache, chills, muscle pain.
The acute period is characterized by recurrent attacks of fever. During an attack, there is a clear change in the stages of chills, fever and sweating. During chills, which can last from half an hour to 3 hours, the body temperature rises, but the patient cannot warm up in any way, and cyanosis of the extremities is observed. The pulse quickens, blood pressure rises, and breathing becomes shallow.
The period of chills ends and a febrile period begins, the patient warms up, and the body temperature can rise to 40–41C. The patient's face turns red, becomes dry and hot, psycho-emotional agitation, anxiety, and confusion are noted. Patients complain of headaches and sometimes have convulsions.
Towards the end of the period of fever, body temperature drops very quickly, which is accompanied by profuse (very profuse) sweating. The patient quickly calms down and falls asleep. This is followed by a period of apyrexia, during which the patient with malaria will maintain normal body temperature and satisfactory health. But the attacks will be repeated with a certain cyclicity, which depends on the type of pathogen.
During attacks, patients experience an enlargement of the spleen and liver and the development of anemia. Malaria affects almost all body systems. The most severe lesions are observed in the cardiovascular (cardiac dystrophy), nervous (neuritis, migraine), genitourinary (nephritis) and hematopoietic systems.
Typically, each patient has 10–12 acute attacks, after which the infection subsides and a secondary latent period of malaria begins.
If ineffective or improper treatment After a few weeks or months, relapses of the disease occur.
Features of types of malaria depending on the type of pathogen:
- Three-day malaria. The incubation period can last from 10 days to 12 months. The prodromal period usually has general symptoms. The disease begins acutely. During the first week, the fever is of an irregular nature, and then a fever is established, in which attacks are repeated every other day. Attacks usually occur in the first half of the day, there is a clear change in the stages of chills, fever and sweating. After 2–3 attacks, the spleen noticeably enlarges, and anemia develops at 2 weeks of illness.
- Ovale malaria in its manifestations is very similar to three-day malaria, but the disease is milder. The minimum incubation period lasts 11 days. Fever attacks most often occur in the evening.
- Quaternary malaria is considered a benign form of malarial infection. The duration of the incubation period usually does not exceed 42 days (at least 25 days), and attacks of fever clearly alternate after 2 days. Enlarged spleen and anemia are rare.
- Tropical malaria is characterized by a short incubation period (on average 7 days) and the presence of a typical prodromal period. Patients with this form of malaria often have no typical symptoms attack. The period of chills may be mild or absent, the febrile period may be prolonged (up to 30–40 hours), the temperature decreases without significant sweating. Patients experience confusion, convulsions, and insomnia. They often complain of abdominal pain, nausea, vomiting and diarrhea.
Treatment of malaria
Artemisia annua extract is effective in the treatment of malaria. There are few treatments for this serious illness. The most reliable and proven drug for the treatment of malaria has been quinine for decades. Doctors have repeatedly tried to replace it with another drug, but invariably returned to this drug.
An extract of wormwood (Artemisia annua), which contains the substance artemisinin, is highly effective in the treatment of malaria. Unfortunately, the drug is not widely used due to its high price.
Prevention of malaria
- Reception preventive medications These funds are justified when it is necessary to visit areas where the risk of malaria infection is increased. To prescribe the drug, you must consult a doctor. It should be noted that it is necessary to start taking preventive medications in advance (1-2 weeks before leaving for a dangerous area) and continue taking them for some time after returning from a dangerous area.
- Destruction of mosquitoes - carriers of infection.
- Use of protective mosquito nets and repellents.
Which doctor should I contact?
If you are planning to travel to areas where malaria is common, contact an infectious disease or tropical disease specialist for advice on how to prevent the disease. If, upon returning home, you begin to experience attacks of fever, you also need the help of an infectious disease specialist. If complications develop, assistance will be provided by appropriate specialists - a cardiologist, neurologist, hematologist, nephrologist.
Elena Malysheva in the program “Live Healthy!” talks about malaria (see from 36:30 min.):
A story about malaria in the program “Morning with the Province”:
Malaria includes a group of acute infectious diseases transmitted primarily through blood. Variant names: intermittent fever, paludism, swamp fever. Pathological changes are caused by Anopheles mosquitoes and are accompanied by damage to blood cells, attacks of fever, and enlargement of the liver and spleen in patients.
Historical aspects
The historical focus of this disease is Africa. From this continent, malaria spread throughout the world. At the beginning of the 20th century, the number of cases was about 700 million per year. One out of 100 infected people died. Level medicine XXI century, reduced morbidity to 350-500 million cases per year and reduced mortality to 1-3 million people per year.
Malaria was first described as a separate disease in 1696, at the same time official medicine At that time, it was proposed to treat the symptoms of pathology with cinchona bark, which had been used in traditional medicine for a long time. The effect of this medicine could not be explained, because healthy person When taken, quinine caused complaints similar to fever. In this case, the principle of treating like with like, which was preached by Samuel Hahnemann, the founder of homeopathy, was applied in the 18th century.
The name of the disease that is familiar to us has been known since 1717, when the Italian physician Lancini established the cause of the development of the disease, coming from the “rotten” air of swamps (mal`aria). At the same time, suspicion arose that mosquitoes were responsible for transmitting the disease. The 19th century brought many discoveries in establishing the causes of malaria, describing the development cycle and classifying the disease. Microbiological studies made it possible to find and describe the infectious agent, which was named malarial plasmodium. In 1897 I.I. Mechnikov introduced the pathogen into the classification of microorganisms as Plasmodium falciparum(class of Sporozoans, type of protozoa).
In the 20th century they developed effective medicines for the treatment of malaria.
Since 1942 P.G. Müller proposed the use of the powerful insecticide DDT to treat areas of disease outbreaks. In the middle of the 20th century, thanks to the incarnation global program elimination of malaria, it was possible to limit the incidence to 150 million per year. In recent decades, an adapted infection began new attack on humanity.
Pathogens of malaria
Under normal conditions, human malaria is transmitted by 4 main types of microorganisms. Cases of infection with this disease have been described in which the pathogens are not considered pathogenic for humans.
Features of the life cycle of malarial plasmodium
The causative agent of the disease goes through two phases of its development:
- sprorogony– development of the pathogen outside the human body ;
- schizogony
Sprorogony
When a mosquito (female Anopheles) bites a person who is a carrier of malaria germ cells, they enter the stomach of the insect, where the fusion of the female and male gametes occurs. The fertilized egg implants into the submucosa of the stomach. There the maturation and division of the developing plasmodium occurs. From the destroyed wall, more than 10 thousand developing forms (sporozoites) penetrate into the hemolymph of the insect.
The mosquito is infectious from now on. When another person is bitten, the sporozoites enter the body, which becomes the intermediate host of the developing malarial microorganism. The development cycle in the mosquito body lasts about 2-2.5 months.
Schizogony
In this phase we observe:
- Tissue stage. Sporozoites penetrate liver cells. There, they successively develop into trophozoites - schizonts - merozoites. The stage lasts from 6 to 20 days, depending on the type of plasmodium. Can be introduced into the human body simultaneously different types causative agent of malaria. Schizogony can occur immediately after introduction or after some time, even months, which contributes to repeated returns of attacks of malaria.
- Erythrocyte stage. Merozoites penetrate the red blood cell and transform into other forms. Of these, from 4 to 48 merozoites are obtained, then morulation occurs (exit from the damaged erythrocyte) and re-infection of healthy erythrocytes. The cycle repeats. Its duration, depending on the type of plasmodium, ranges from 48 to 72 hours. Some merozoites turn into germ cells, which infect a mosquito that bites a person and transmits the infection to other people.
Note:In the case of malaria infection not from mosquitoes, but through a blood transfusion containing Plasmodium merozoites, only the erythrocyte stage occurs in the infected person.
In every detail life cycle Plasmodium is described in the video review:
How does malaria become infected?
Children are especially susceptible to infection. The incidence in the foci is very high. Some people are resistant to malaria. It especially develops after repeated infections. Immunity does not last a lifetime, but only for an indefinite period.
Note:Malaria is characterized by a seasonal onset. Summer and hot months are most favorable for vectors of infection. In hot climates, the disease can occur all year round.
Malaria occurs in certain foci, monitoring of which makes it possible to predict the beginning of the seasonal surge, its maximum and attenuation.
In the classification, foci are divided into:
- seaside;
- flat;
- hilly-river;
- plateau;
- mid-mountain river.
The intensity of transmission and spread of malaria is assessed according to four types:
- hypoendmic;
- mesoendemic;
- hyperendemic;
- holoendemic.
The holoendemic type has the highest risk of infection and is characterized by the most dangerous forms diseases. The hypoendemic type is characteristic of isolated (sporadic) cases of malaria.
Development of the disease and characteristic changes in the body
Note:the main pathological reactions occur as a result of the onset of erythrocyte schizogony.
The released biogenic amines contribute to the destruction of the vascular wall, causing electrolyte disturbances, irritation of the nervous system. Many components of the life activity of plasmodia have toxic properties and contribute to the production of antibodies and protective immunoglobulin complexes against them.
The system reacts by activating the protective properties of the blood. As a result of phagocytosis (destruction and “eating” of diseased cells), the destruction of damaged red blood cells begins, causing anemia (anemia) in humans, as well as increased function of the spleen and liver. The total content of blood cells (erythrocytes) decreases.
Clinically, at these stages a person develops different kinds fever. Initially, they are irregular, non-cyclical, and are repeated several times a day. Then, as a result of the action of immune forces, one or two generations of plasmodia remain, which cause attacks of fever after 48 or 72 hours. The disease acquires a characteristic cyclical course.
Note:the invasion process can last from 1 year to several decades, depending on the type of pathogen. Immunity after past illness unstable. Repeated infections often occur, but with them the fever is mild.
Against the background of malaria occur pathological processes in the brain, symptoms of edema and wall damage appear small vessels. The heart also suffers, in which severe degenerative processes occur. Necrobiosis forms in the kidneys. Malaria attacks the immune system, causing the development of other infections.
The disease occurs with periods of exacerbation of fever and normal state.
Main symptoms of malaria:
- attacks of fever (chills, fever, sweating);
- anemia (anemia);
- enlargement of the spleen and liver (hepatosplenomegaly);
- decrease in the number of red blood cells and platelets (pancytopenia).
As with most infectious diseases, there are three forms of severity of malaria - mild, moderate, severe.
The onset of the disease is sudden. It is preceded by an incubation period (the period of time from infection to the onset of the disease).
It amounts to:
- vivax malaria – 10-21 days (sometimes up to 10-14 months);
- four-day malaria – from 3 to 6 weeks;
- tropical malaria – 8-16 days;
- ovale malaria – 7-20 days.
Sometimes there is a prodromal period (the time of onset of malaria, accompanied by initial, mild symptoms). The patient experiences weakness, chilling, thirst, dry mouth, pain in the head.
Then a fever of the wrong type suddenly appears.
Note:The first week of the febrile period is characterized by attacks occurring several times a day. In the second week, paroxysms acquire a clear cyclic course, repeating every other day or two (with four-day fever)
How does a fever attack proceed?
The duration of the paroxysm is from 1-2 hours to 12-14 hours. A longer period is determined for tropical malaria. It can last a day or even more than 36 hours.
Attack phases:
- chills – lasts 1-3 hours;
- fever - up to 6-8 hours;
- profuse sweating.
Complaints and symptoms during malarial paroxysm:
After sweating comes sleep. During the interictal period, patients are able to work, but as the disease progresses, their condition worsens, there is loss of body weight, jaundice, and the skin becomes sallow in color.
Tropical malaria is the most severe.
In her case, the following are added to the described symptoms of malaria:
- severe pain in the joints and throughout the body;
- signs characteristic of meningitis;
- delusional state of consciousness;
- attacks of suffocation;
- frequent vomiting with blood;
- pronounced enlargement of the liver.
In the first week of illness, attacks can occur, layering on each other. A few months after the onset of the disease, paroxysms begin to recur, but in a milder form.
Of all the described forms of malaria, vivax is the most mild. The most big number relapses are observed with Chesson malaria (Pacific form).
note:Cases of a fulminant course have been described, which led to death from cerebral edema within a few hours.
Complications of malaria
In weakened or untreated patients, as well as in case of treatment errors, the following complications may develop:
- malarial coma;
- edema syndrome;
- extensive hemorrhages (hemorrhages);
- different types of psychoses;
- renal and liver failure;
- infectious complications;
- splenic rupture.
A separate complication of malaria should be noted hemoglobinuric fever. It develops against the background of massive proliferation of plasmodia, during treatment with medications, due to the destruction of red blood cells (hemolysis). IN severe cases this complication general symptoms and complaints of an attack of malaria are added by a progressive decrease in urine production. Lightning develops renal failure, often with early death.
Diagnosis of malaria
Malaria is determined based on:
- collection of anamnestic data - the survey reveals pre-existing malaria, cases of blood transfusion to the patient;
- epidemiological history – the patient’s residence in areas with existing outbreaks of the disease;
- clinical signs - the presence of characteristic complaints and symptomatic picture malaria;
- laboratory diagnostic methods.
The first three points are discussed in detail in the article. Let's touch on laboratory testing methods.
These include:
Confirmation of diagnosis using specific methods
To confirm the diagnosis, blood is tested using "thick drop" And "smear".
The analysis allows you to determine:
- a type of malarial plasmodium;
- stage of development;
- level of invasiveness (number of microbes).
Invasiveness is assessed in 4 degrees (in the field of view of the microscope):
- IVdegree– up to 20 cells per 100 fields .
- IIIdegree– 20-100 plasmodia per 100 fields.
- IIdegree– no more than 10 in one field;
- Idegree– more than 10 in one field.
The method is quite simple, cheap and can be used frequently to monitor the patient’s condition and the effectiveness of treatment.
Analysis "thin drop" is prescribed as an addition to the previous one in case of necessary differential diagnosis.
An express diagnostic method is immunological analysis determination of specific proteins of falciparum plasmodium. It is carried out in foci of tropical malaria.
Serological tests for malaria
Material – deoxygenated blood.
The goal is to detect antibodies to malaria .
Result assessment – titer less than 1:20 – negative test; more than 1:20 – positive.
Polymerase chain reaction ()
The test is specific in nature, allowing it to detect malaria in 95% of cases. Venous blood is used. Negative point- high cost. Required in doubtful cases.
Mosquitoes are also tested for the presence of Plasmodium falciparum cells.
Treatment of malaria
Modern treatments for malaria are very effective. They are shown on different stages diseases. Today a large number of medical supplies that allow you to cope with the disease even in advanced situations. Let us dwell on the principles of treatment and a description of the main drug groups.
Note: Therapy must be started immediately after diagnosis in an infectious diseases hospital.
Goals of malaria treatment:
- destruction of the pathogenic plasmodium in the patient’s body;
- treatment of associated complications;
- prevention or mitigation of relapse clinics;
- stimulation of specific and nonspecific immunity.
Groups of medications for the treatment of malaria
To main groups medicines include:
- Quinolylmethanols - derivatives of Quinine, Delagil, Plaquenil, Lariam, Primaquine.
- Biguanides – Bigumal.
- Diaminopyrimidines – Daraprim.
- Terpene lactones – Artesunate.
- Hydroxynaphthoquinones – Mepron.
- Sulfonamides.
- Tetracycline antibiotics.
- Lincosamides – Clindamycin.
People with malaria need care. Diet – table 15 according to Pevzner during periods of remission and table 13 during a febrile period. Recommended - lean meat and fish, soft-boiled eggs, porridge, kefir, fermented baked milk, boiled vegetables, fresh pureed fruit, juices, fruit drinks, crackers, honey.
Preventive actions
Preventive work is carried out at the site of infection through the use of mosquito nets and insecticides, which are used to treat areas where mosquitoes accumulate. At home, it is necessary to use repellents, aerosols and ointments that repel mosquitoes and cause their death.
If you suspect possible infection medications are taken in doses prescribed by the infectious disease specialist.
Vaccine prevention is currently being developed.
People at the epicenter of the epidemic, when elevated temperature subject to isolation and laboratory examination. The earlier treatment is started, the better the result. People arriving from countries with malaria outbreaks must be examined. Those who have recovered from the disease must be observed by an infectious disease specialist for 3 years.
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