Chronic malaria. Pathogenesis and clinical manifestations of malaria. Development of the disease and characteristic changes in the body

Malaria is a dangerous infectious disease caused by mosquito bites. The causative agent is the microbe Plasmodium.

Residents and travelers visiting countries in Africa, Southeast Asia and Latin America are at greatest risk of contracting malaria because

Main symptoms: increased body temperature to 38-39C, chills, headache, severe weakness, pain in muscles and joints. Severe forms of the disease can lead to kidney failure, coma, and even death.

The following methods are used in the diagnosis of malaria: studying blood under a microscope, detecting special antibodies and genetic material of the pathogen in the blood.

Antimalarial drugs are used in treatment. As a preventative measure, all travelers to countries with a high risk of contracting malaria should use insect repellents or regularly take antimalarial medications.

What do we know about the causative agent of malaria?

Plasmodium enters the human body through the bite of an Anopheles mosquito. In total, there are about 20 species of mosquitoes that can transmit malaria to humans. Their peculiarity is that they bite only at night. In addition, these mosquitoes breed in water, so the greatest risk of contracting malaria is in areas with high humidity, near bodies of water, and during the rainy seasons.

People living or traveling to countries in Africa, Southeast Asia, and Latin America are at risk of contracting malaria.

Malaria develops only when the pathogen enters the human blood. There are 3 main routes of infection:

1. Through the bite of a mosquito infected with Plasmodium.
2. Transfusion of contaminated blood.
3. During pregnancy, a mother infected with malaria passes the disease to her child.

A person with malaria is not dangerous to others and cannot infect his loved ones. Infection is possible only through blood transfusion or organ transplantation from a sick person to a healthy one.

Why is malaria dangerous?

When a mosquito infected with Plasmodium bites, malaria pathogens enter the human bloodstream. Having penetrated the blood vessels, plasmodia reach the liver, where they begin to reproduce. After some time, they enter the blood again, where they continue to multiply in red blood cells - erythrocytes. Plasmodium proliferation causes the death of red blood cells.

Dead blood cells stick together, forming clots. These clots block the lumen of the blood vessels, which disrupts the blood supply to the organs. This leads to disruption of the kidneys, liver, lungs, and brain, and without treatment the person dies.

Symptoms and signs of malaria

The incubation period (time from infection with malaria until the first symptoms appear) ranges from 7 to 14 days. However, cases have been described in which the first signs of malaria appeared in a person 6-12 months after infection.

The first symptoms of malaria may resemble a cold:

1. The main symptom is an increase in body temperature to 38-39C. It lasts for several hours and is accompanied by severe chills. The temperature then drops, causing heavy sweating.
2. Pain in muscles, joints.
3. Weakness, drowsiness.
4. Decreased appetite.
5. The skin becomes pale or acquires a yellowish tint.

If you are in an area where malaria is possible, or have recently returned from there and notice similar symptoms, consult your doctor immediately.

It is extremely important to begin treatment within the first 24 hours after symptoms appear. Delay in treatment can lead to kidney failure, pulmonary edema, coma, and even death.

Diagnosis of malaria

The following methods are used in the diagnosis of malaria:

Antimalarial drugs are used to treat malaria. There are several drugs that are effective in its treatment: Chloroquine, Quinine, Doxycycline, Tetracycline, Primaquine, Artemisin, etc.

Most antimalarial drugs come in tablets or capsules. Intravenous administration of drugs is required extremely rarely, only in cases of severe disease.

After recovery

Malaria caused by P. vivax and P. ovale may return even after complete recovery. These types of plasmodia are able to remain dormant in the liver for several years after malaria infection. Therefore, if you have had malaria before and have symptoms of the disease again, you should see your doctor and get tested again.

If you have had malaria, you cannot donate blood for at least 3 years after recovery. After this period, if you decide to become a donor, be sure to inform the blood transfusion center that you have had malaria.

Malaria during pregnancy

In pregnant women, malaria is usually more severe and can lead to miscarriage or premature birth. If a pregnant woman lives (or travels) in an area with a high risk of contracting malaria, she needs to take disease prevention seriously (see below).

If malaria infection does occur, then treatment should be carried out by an experienced specialist. Most drugs used in the treatment of malaria are safe for the unborn child and will not affect its intrauterine development.

Malaria in children

In children, malaria is more aggressive than in adults, and without treatment it leads to the development of serious complications much more quickly.

In the treatment of malaria in children, the same drugs are used as in adults, but in a lower dose (depending on the age and weight of the child).

Prevention of malaria

A vaccine for malaria is currently in development and is not yet available to most people. The main methods of prevention are protection from the bites of insects that carry the disease, as well as prophylactic use of antimalarial drugs.

1. When traveling or living in an area with a high risk of malaria infection, follow these recommendations:
2. Protect yourself from mosquito bites that can infect you. The mosquitoes that transmit malaria only bite at night, so it is essential to avoid contact with mosquitoes from sunset to dawn.
3. Wear clothing that covers most of your torso, arms and legs.
4. Use insect repellents that contain DEET (or DEET). The repellent should be applied not only to the skin, but also to clothing, shoes, bags, etc. A spray containing 95% DEET is suitable for use by adults; it provides protection against mosquitoes for 10-12 hours. A spray containing 35% DEET is effective for 3-4 hours. After you leave an area with a high risk of insect bites, you should immediately wash off any remaining spray from your skin.
5. In the room where you sleep, use mosquito nets on the windows or a curtain impregnated with permethrin (a substance that repels mosquitoes). A canopy is a net that you install over your bed or sleeping bag.
6. If you are traveling to an area with a very high incidence of malaria, contact an infectious disease doctor or epidemiologist and discuss the possibility of malaria chemoprophylaxis. Chemoprophylaxis is the prophylactic use of antimalarial drugs for the duration of the trip and for some time after return. The choice of drug depends on the country you are traveling to.
7. If you are bitten by a mosquito or if you notice symptoms similar to those of malaria (fever, chills, weakness, headache, nausea, etc.), seek medical help immediately.

The fear of contracting an infectious disease is familiar to many travelers to tropical countries. It is in warm regions that most pathogens of severe pathologies in the human body live. One such disease is tropical malaria.

What kind of disease is this, what are the causes and sequence of its occurrence, what are the symptoms and treatment and how to help the body quickly get rid of this terrible disease - read in our publication.

Description of the infection

At the moment, science has identified five types of plasmodia - the causative agents of this pathology.

The disease gets its name from the Italian word malaria. In translation, malaria means bad, spoiled air. Another name for this disease is also known - swamp fever. This is explained by the fact that, along with hepatolienal syndrome (enlarged liver and spleen) and anemia (anemia), paroxysmal fever is considered the main symptom of malaria.

“Every year, malarial fever causes the death of 3 million people, including one million young children.”

The main source of infection for malaria is the bite of a female anopheles mosquito, as male Anopheles mosquitoes feed on the nectar of flowers. Infection occurs when the causative agent of the disease, a strain of malaria, enters the human blood:

• After being bitten by an Anopheles mosquito.
• From mother to child during pregnancy and childbirth.
• Through the use of non-sterile medical instruments with remains of infected blood cells.

People have been suffering from malaria since ancient times. The intermittent fever associated with the disease is described in a Chinese chronicle dating back to 2700 BC. e. The search for the main cause of malaria lasted for millennia, but the first success came to doctors in 1880, when the French doctor Charles Laveran was able to detect plasmodia in the blood of an infected patient.

Malaria has been known since ancient times

Among women: pain and inflammation of the ovaries. Fibroma, myoma, fibrocystic mastopathy, inflammation of the adrenal glands, bladder and kidneys develop.

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Features of human infection

Anopheles, the genus of which the malarial mosquito belongs to, lives on almost all continents, with the exception of territories whose climate is too harsh - Antarctica, the Far North and Eastern Siberia.

However, malaria is caused only by those members of the Anopheles genus that live in southern latitudes, since the Plasmodium they carry can only survive in warm climates.

With the help of the image you will learn what a malaria mosquito looks like.

The main carrier of the disease is mosquitoes.

“According to WHO, 90% of cases of infection are registered in Africa.”

Anopheles are blood-sucking insects. Therefore, malaria is considered a disease of vector-borne etiology, that is, an infection transmitted by blood-sucking arthropods.

The life cycle of Anopheles takes place near bodies of water, where the mosquito lays eggs and larvae appear. For this reason, malaria is common in waterlogged and swampy areas. An increase in incidence can be observed during periods of heavy rains that replace drought, as well as as a result of population migration from epidemiologically disadvantaged regions.

The extent of infection is determined by the number of bites from infectious mosquitoes per year. In Southeast Asian countries, this figure rarely reaches one, while residents of tropical Africa can be attacked by insect vectors more than 300 times a year.

The main distribution area of ​​the disease is tropical latitudes.

Like many infectious diseases, epidemics and acute outbreaks of malaria are most often found in endemic areas or in remote areas where people do not have access to necessary medicines.

To reduce the incidence rate, modern epidemiology recommends vaccination of people living in swampy areas where the disease is usually common.

Types of pathology

The development of various forms of malaria is provoked by different types of Plasmodium.

The most common and one of the most dangerous types of disease is tropical malaria. It is characterized by fulminant damage to internal organs, a rapid course of the disease, and a large number of severe complications. Often leads to death. Treatment of the infection is complicated by the strain's resistance to most antimalarials. The causative agent is Plasmodium falciparum.

This type of infection is characterized by remitting fever with significant daily temperature fluctuations, including a critical decrease in its parameters. The attacks are repeated at short intervals. The infection lasts for a year.

As a rule, with tropical malaria, cerebral, septic, algid and renal forms of pathologies develop, as well as malarial coma, increased tendon reflexes and a coma.

Three-day malaria is the result of infection with a strain of Plasmodium vivax. In its course, the three-day form of the pathology is similar to oval malaria, caused by the Plasmodium ovale strain, which is much less common. If attacks of malaria are similar in symptoms, then the methods of treatment are usually the same.

Incubation of strains that cause a three-day form of infection is short and long, depending on the type of plasmodium. The first signs of three-day malaria can appear either after 14 days or after 14 months.

Its course is characterized by multiple relapses and the appearance of complications in the form of hepatitis or nephritis. The pathology responds well to treatment. The total duration of infection is 2 years.

The disease is characterized by the development of complications.

“Representatives of the Negroid race have antimalarial immunity and are resistant to the Plasmodium vivax strain.”

Quartana malaria is a form of infection with a strain of Plasmodium malariae.

Malaria of the four-day type is characterized by a benign course, without enlargement of the spleen and liver and other pathological conditions that usually develop against the background of the disease. The main symptoms of quartana can be quickly eliminated with medication, but it is difficult to completely get rid of malaria.

“Attacks of quaternary malaria can recur even 10-20 years after the symptoms disappear.”

There are known cases of people becoming infected as a result of blood transfusions from donors who had previously had a four-day form of infection.

Another causative agent of the disease, a strain of Plasmodium knowlesi, was recently discovered. This strain of Plasmodium is known to cause the spread of malaria throughout Southeast Asia. So far, epidemiology does not have complete information about the characteristics of this form of the disease.

All types of malaria differ in symptoms, course and prognosis of the disease.

Specifics of the development of infectious pathology

“Several thousand daughter cells can develop from a single sporozoite, enhancing the progression of the disease.”

Subsequent stages of development of the pathogen determine all the pathological processes that characterize the clinical picture of malaria.

• Tissue schizogony.

The disease has several stages of development.

Moving along with the bloodstream, plasmodia penetrate liver hepatocytes and are divided into forms of fast and slow development. Subsequently, chronic malaria arises from a slowly developing form, causing numerous relapses. After destroying liver cells, plasmodia penetrate blood vessels and attack red blood cells. At this stage, clinical symptoms of malaria do not appear.

• Erythrocyte schizogony.

Having penetrated into red blood cells, schizonts absorb hemoglobin and increase in size, which causes rupture of the red blood cell and the release of malarial toxins and newly formed cells - merozoites - into the blood. Each merozoite again invades the erythrocyte, starting a repeat cycle of damage. At this stage of malaria, a characteristic clinical picture appears - fever, enlargement of the spleen and liver.

• Gametocytogony.

The final stage of erythrocyte schizogony, which is characterized by the formation of plasmodium germ cells in the blood vessels of human internal organs. The process is completed in the mosquito’s stomach, where gametocytes enter along with the blood after the bite.

The life cycle of Plasmodium, which causes malaria, is presented in the video below.

The length of the Plasmodium life cycle affects the incubation period of malaria.

Manifestations of symptoms

From the moment an infectious pathogen enters the human body to the stage when the pathological anatomy of malaria appears, a lot of time can pass.

Quadrilateral malaria may appear within 25-42 days.

The pathogenesis of tropical malaria occurs relatively quickly - within 10-20 days.

Three-day malaria has an incubation period of 10 to 21 days. Infection, transmitted by slowly developing forms, becomes acute within 6-12 months.

Oval malaria manifests itself in 11-16 days, when infected with slowly developing forms - from 6 to 18 months.

Depending on the period of development of the disease, the symptoms of malaria differ in intensity and nature of manifestations.

• Prodromal period.

The first signs of the disease are nonspecific and look more like a viral infection than a serious disease such as malaria. The malaise is accompanied by headaches, deterioration of health, weakness and fatigue, periodically manifested by muscle pain and a feeling of discomfort in the abdomen. The average duration of the period is 3-4 days.

• Period of primary symptoms.

Occurs when an attack of fever occurs. Paroxysm, characteristic of the acute period, appears in the form of successive stages - chills with a temperature increase from 39 ° C and lasting up to 4 hours, fever with a temperature increase up to 41 ° C and lasting up to 12 hours, increased sweating, lowering the temperature to 35 ° C.

• Interictal period.

During it, body temperature normalizes and well-being improves.

Symptoms of the disease depend on the stage.

In addition, consequences of malaria such as yellowing of the skin, confusion, drowsiness or insomnia, and anemia are observed.

Features of pathological changes

Depending on the type of disease, malarial paroxysm is determined by specific characteristics. The definition of tertian malaria is a short morning attack occurring every other day. The duration of the attack is up to 8 hours.

The four-day form is characterized by repetition of attacks every two days.

During the tropical form of the disease, short interictal periods (3-4 hours) are observed, and the temperature curve is characterized by a predominance of fever for 40 hours. Often the body of patients cannot withstand such a load, which leads to death.

With a long course of the disease, the plasmoid pigment is absorbed by internal organs.

Complications of malaria in the form of enlarged organs in children can be detected a few days after the onset of the disease by palpation. Children, unlike adults, are not protected by immunity that can resist infection.

In the tropical form of infection, pathological anatomy is observed in the brain, pancreatic and intestinal mucosa, heart and subcutaneous tissue, in the tissues of which stasis is formed. If a patient has had a malarial coma for more than a day, pinpoint hemorrhage and necrobiosis in certain areas of the brain are possible.

The pathomorphology of three-day and four-day malaria is practically the same.

Elimination of the consequences of infection

To diagnose an infectious lesion in medicine, a general blood test, urinalysis, biochemical analysis, as well as clinical, epidemic, anamnestic criteria and laboratory test results are used.

Differential diagnostic testing of patients' blood smears to detect malaria and possible complications is indicated in all patients with symptoms of fever. The procedure is prescribed before the start of treatment.

Often the source of infection becomes donors - carriers of pathogens transmitted through blood.

As soon as the diagnosis is confirmed, the patient is hospitalized in an infectious diseases hospital and treatment is prescribed.

The objectives and goals of treatment measures are summarized in the form of a small manual:

Treatment has a number of main directions.

• The vital activity of the pathogen in the patient’s body must be interrupted.
• The development of complications should be prevented.
• Do everything to save the patient’s life.
• Ensure prevention of the development of a chronic form of pathology and the occurrence of relapses.
• Prevent the spread of the infectious agent.
• Prevent plasmodia from developing resistance to antimalarial drugs.

The basis of medical care for the patient is drugs of hematoschizotropic action (Hingamin, Delagil, Chloridine) and gametocidal action (Delagil). In the acute course of the disease, the patient is provided with complete rest, plenty of fluids, and protection from hypothermia. Additionally, a diet aimed at increasing immunity and general strengthening of the patient’s body, and folk remedies for malaria are recommended.

Even a strong and healthy man finds it difficult to cope with the infection on his own. Without the help of professional doctors, the disease can cause such serious complications as malarial coma, the development of hemorrhagic and convulsive syndrome, malarial algid, cerebral edema, renal failure, urinary retention, the appearance of hemorrhagic rash, disseminated intravascular coagulation syndrome, etc.

The fight against malaria involves measures to prevent the disease - protection from mosquito bites, vaccination and taking antimalarial drugs.

The disease is very insidious. It must be treated under constant medical supervision. At home, it is impossible to achieve the desired effect; at best, it will be possible to remove the symptoms of the disease. However, this is not enough - to avoid relapse, long-term adequate treatment is needed.

Malaria is an acute febrile disease. In a person who is not immune, symptoms usually appear 10 to 15 days after being bitten by an infected mosquito. The first symptoms—fever, headache, and chills—may be mild, making malaria difficult to detect. If treatment is not started within the first 24 hours, malaria P. falciparum can develop into a serious illness, often ending in death.

Children with severe malaria often develop one or more of the following symptoms: severe anemia, respiratory failure due to metabolic acidosis, or cerebral malaria. Adults also often experience multiple organ failure. In areas where malaria is endemic, people may develop partial immunity, in which infections occur without symptoms.

Who is at risk?

In 2018, nearly half the world's population was at risk of malaria. Most malaria cases and deaths occur in sub-Saharan Africa. However, WHO regions such as South-East Asia, the Eastern Mediterranean, the Western Pacific and the Americas are also at risk.

The risk of contracting malaria and developing severe disease is significantly higher among some groups of the population. These groups include infants, children under five years of age, pregnant women and people with HIV/AIDS, as well as non-immune migrants, mobile populations and travelers. National malaria control programs need to take special measures to protect these populations from malaria infection, taking into account their specific circumstances.

Burden of disease

According to the latest edition released in December 2019, 228 million people worldwide fell ill with malaria in 2018, up from 231 million in 2017. That year, an estimated 405,000 people died from malaria, up from 461,000 people in 2017

The WHO African Region continues to bear a disproportionate share of the global malaria burden. In 2018, the region accounted for 93% of malaria cases and 94% of malaria deaths.

In 2018, more than half of all malaria cases in the world occurred in six countries: Nigeria (25%), Democratic Republic of the Congo (12%), Uganda (5%), Ivory Coast, Mozambique and Niger (4% each). every).

Children under five years of age are especially susceptible to malaria; in 2018 they accounted for 67% (272,000) of all malaria deaths worldwide.

• - in English

Transmission of infection

Mosquitoes Anopheles They lay eggs in the water and hatch into larvae that eventually develop into adult mosquitoes. Female mosquitoes need blood to lay eggs. Every type of mosquito Anopheles has its own aquatic habitat; some, for example, prefer small, shallow accumulations of fresh water, such as puddles and hoof marks, which are abundant during the rainy season in tropical countries.

Transmission of infection also depends on climate features, such as rainfall patterns, temperature and humidity, which also affect the number and survival of mosquitoes. In many places, transmission is seasonal and peaks during and immediately after the monsoon seasons. Malaria epidemics can occur when climatic and other conditions suddenly become favorable for transmission in areas where people have little or no immunity to malaria. In addition, epidemics can occur when people with weak immune systems enter areas with intense malaria transmission, for example to seek work or as refugees.

Another important factor is human immunity, especially among adults in areas with moderate to intense transmission. Partial immunity develops over several years of exposure, and although it never provides complete protection, it reduces the risk of developing severe illness in the event of a malaria infection. For this reason, most malaria deaths in Africa occur among young children, while in areas with less intense transmission and low immunity, all age groups are at risk.

Prevention

The main way to prevent and reduce malaria transmission is vector control. Sufficiently high coverage of a particular area with vector control measures provides some protection from infection to the entire population of the area.

To protect all people at risk of malaria, WHO recommends effective vector control measures. To do this, two methods can be effectively used in a wide variety of conditions - insecticide-treated mosquito nets and spraying residual insecticides indoors.

Insecticide treated mosquito nets

The use of insecticide-treated mosquito nets (ITNs) during sleep may reduce the likelihood of mosquito-human contact through both the presence of a physical barrier and exposure to the insecticide. Mass eradication of mosquitoes in areas where such nets are widely available and actively used by local residents can provide protection to the entire population.

Insecticide-treated nets in Africa protected about half of all people at risk of malaria in 2018, up from 29% in 2010. However, ITN coverage has shown little growth since 2016.

Spraying residual insecticides indoors

Another effective way to rapidly reduce malaria transmission is indoor residual spraying (IRID). Insecticide spraying inside residential areas is carried out once or twice a year. To achieve effective protection of the population, a high level of RIODVP coverage must be ensured.

Globally, the rate of use of RADI for protection has decreased from a peak of 5% in 2010 to 2% in 2018 in all WHO regions except the Eastern Mediterranean Region. The decline in MRV coverage occurs as countries shift from using pyrethroid pesticides to more expensive alternatives to address pyrethroid resistance in mosquitoes.

Antimalarial drugs

Antimalarial drugs can also be used to prevent malaria. Prevention of malaria among travelers can be achieved through chemoprophylaxis, which suppresses the blood stage of malaria infection, thereby preventing the disease from developing. Among pregnant women living in areas of moderate to intense transmission, WHO recommends intermittent sulfadoxine-pyrimethamine preventive therapy at every routine antenatal visit after the first trimester of pregnancy. Similarly, intermittent preventive therapy with three doses of sulfadoxine-pyrimethamine as part of routine vaccination is recommended for infants living in areas of Africa with high transmission rates.

Since 2012, WHO has recommended seasonal malaria chemoprophylaxis in areas of the Sahel subregion as an additional malaria prevention strategy. This strategy involves administering monthly courses of amodiaquine plus sulfadoxine-pyrimethamine to all children under five years of age during the high transmission season.

Insecticide resistance

Since 2000, progress in malaria control has been achieved largely through increased coverage of vector control interventions, particularly in sub-Saharan Africa. However, these achievements are under threat due to the increasing resistance of mosquitoes Anopheles to insecticides. According to the latest edition, between 2010 and 2018, cases of mosquito resistance to at least one of the four most common classes of insecticides were reported in 72 countries. In 27 countries, mosquito resistance to all major classes of insecticides was observed.

Despite the rise and spread of mosquito resistance to pyrethroids, insecticide-treated nets continue to provide significant levels of protection in most areas of human activity. This was confirmed by the results

Despite the encouraging results of this study, WHO continues to reiterate the urgent need for new and improved tools to combat malaria worldwide. WHO also emphasizes the urgent need for all countries where malaria transmission continues to develop and implement effective strategies to combat insecticide resistance to prevent the decline in the effectiveness of the most common vector control tools.

Diagnosis and treatment

Early diagnosis and treatment of malaria helps reduce the severity of the disease and prevent death. These measures also help reduce the intensity of malaria transmission. The most effective treatment regimen available, especially for malaria P. falciparum, is artemisinin combination therapy (ACT).

Ensuring the effectiveness of antimalarial drugs is critical to malaria control and elimination. Regular monitoring of drug effectiveness is required to develop treatment strategies for malaria-endemic countries and to ensure timely detection and control of drug resistance.

At the World Health Assembly in May 2015, WHO adopted, which was endorsed by all countries in the subregion. The strategy aims to eliminate all types of human malaria across the region by 2030 and includes a series of immediate actions, particularly in areas where multidrug-resistant malaria is widespread.

All countries in the subregion, with technical support from WHO, have developed national malaria elimination plans. WHO, together with partners, is providing ongoing support to countries' efforts to eliminate malaria through the Mekong Malaria Elimination Programme, a new initiative that is a continuation of the EMER.

Surveillance

Surveillance involves monitoring cases of disease, systematically responding, and making decisions based on the findings. Currently, many countries with a high malaria burden have weak surveillance systems and are unable to assess the distribution and trends of the disease, making it difficult to optimize responses and respond to outbreaks.

Effective surveillance is needed at all stages of the progress towards malaria elimination. Strengthening malaria surveillance programs is urgently needed to ensure a timely and effective response to malaria in endemic regions, prevent outbreaks and re-emergence of the disease, monitor progress and hold governments and other global actors in the fight against malaria accountable.

In March 2018, WHO released . The guide provides information on global surveillance standards and recommendations for strengthening country surveillance systems.

Elimination

Elimination is expanding around the world, and more countries are moving closer to the goal of reducing malaria incidence to zero. In 2018, the number of countries reporting fewer than 100 cases of local transmission was 27, up from 17 in 2010.

Countries that have not reported a local case of malaria for at least three consecutive years meet the criteria for submitting an application to WHO. In recent years, 10 countries have been certified as malaria-free by the WHO Director General: Morocco (2010), Turkmenistan (2010), Armenia (2011), Maldives (2015), Sri Lanka (2016) .), Kyrgyzstan (2016), Paraguay (2018), Uzbekistan (2018), Algeria (2019) and Argentina (2018). Accepted by WHO Malaria Elimination Framework(2017) provides a comprehensive set of tools and strategies to achieve and maintain elimination.

Vaccines against malaria

Leading WHO advisory bodies on malaria and immunization, given the high public health importance of this vaccine, have jointly recommended its phased introduction in parts of sub-Saharan Africa. In 2019, three countries (Ghana, Kenya and Malawi) began introducing the vaccine in selected areas with moderate to high intensity malaria transmission. Vaccination is carried out as part of the national routine immunization program of each country.

The vaccine pilot program will provide answers to a number of outstanding questions regarding its use in public health. This will be important in understanding the optimal administration schedule for the four recommended doses of RTS,S; the potential role of vaccines in reducing child mortality; and its safety during routine vaccinations.

The program is being coordinated by WHO, together with the ministries of health of Ghana, Kenya and Malawi, as well as a number of national and international partners, including the non-profit organization PATH and GlaxoSmithKline (GSK), the vaccine developer and manufacturer.

Funding for the vaccine development program was provided through a collaboration between three of the world's largest health financing organizations: the Vaccine Alliance GAVI, the Global Fund to Fight AIDS, Tuberculosis and Malaria and UNITAID.

WHO activities

WHO global technical strategy for malaria control 2016–2030.

Adopted by the World Health Assembly in May 2015. sets technical parameters for work in all malaria-endemic countries. It aims to guide and support regional and national programs as they work to control and achieve malaria elimination.

This strategy sets ambitious but achievable global goals, including:

• reducing the incidence of malaria by at least 90% by 2030;
• reducing malaria mortality rates by at least 90% by 2030;
• eliminating malaria in at least 35 countries by 2030;
• preventing the re-emergence of malaria in all malaria-free countries.

The strategy was the result of a broad consultative process over two years involving more than 400 technical experts from 70 Member States.

Global Malaria Program

Ensures coordination of WHO's international efforts to control malaria and achieve its elimination through:

• developing, communicating and promoting their adoption of norms, standards, policies, technical strategies and guidelines;
• independent assessment of global progress;
• developing approaches to strengthen capacity, improve systems and conduct surveillance;
• identifying factors that threaten effective malaria control and elimination, as well as finding new areas of action.

The Program is supported and advised by a Malaria Policy Advisory Committee (MPAC), composed of malaria experts appointed through open nominations. The mandate of the ACPM is to provide policy advice and technical advice on all aspects of malaria control and elimination through a transparent, flexible and credible rule-making process.

"A heavy burden requires high efficiency"

At the World Health Assembly in May 2018, WHO Director-General Dr Tedros Adhanom Ghebreyesus called for a new proactive approach to accelerate progress in the fight against malaria. A new initiative, carried out with the active participation of countries, was launched in November 2018 in Mozambique.

Currently, 11 countries with the highest burden of disease are participating (Burkina Faso, Cameroon, Democratic Republic of the Congo, Ghana, India, Mali, Mozambique, Niger, Nigeria, Uganda and the United Republic of Tanzania). The main elements of the initiative are:

• mobilizing political will to reduce the burden of malaria;
• providing strategic information to achieve real change;
• improving guidelines, policies and strategies;
• coordinated efforts to combat malaria at the national level.

The High Burden Means High Impact initiative, carried out with the active participation of WHO and the WOM Partnership to End Malaria, is based on the principle that no one should die from a disease that is preventable and diagnosable and completely curable with existing medicines.

In contrast to the so-called “benign” clinical forms of malaria caused by Pl. vivax, Pl. ovale and Pl. malaria, tropical malaria(the causative agent is Pl. falciparum) is considered a potentially fatal infection and therefore almost always requires emergency medical care, especially with complications, that is, malignant variants.

The causative agent of malaria

The causative agent of malaria is Plasmodium falciparum are the simplest microorganisms studied by protozoology.

Pathogenesis

Clinically, the symptoms of tropical malaria in non-immune people are characterized by a combination of fever, hemolytic anemia, enlarged spleen and liver, severe intoxication and symptoms of damage to other organs.

The incubation period for primary tropical malaria usually lasts 10-14 days. In the initial period of the disease, symptoms of intoxication are expressed in the form of chills, significant headache, myalgia and arthralgia. A sudden fever becomes permanent or remitting in nature and only after 2-5 days in some patients it becomes typical intermittent with periods of apyrexia and low-grade fever on the same day. In some patients, classic malarial paroxysms can occur daily, and in some patients they do not develop at all and the fever remains remitting or subcontinuous.

Malarial paroxysms in tropical malaria are characterized by the triad of “chills-fever-sweats”, but the severity of each component may be different, unlike other etiological forms. During an attack, the symptoms of general intoxication are most pronounced. Patients are restless, excited, sometimes with confused consciousness. Herpetic rash, pain in the right hypochondrium, lower back pain and anemia appear early and often. The spleen and later the liver enlarge. Jaundice and toxic kidney syndrome appear.

Some patients with tropical malaria have a cough with signs of bronchitis and even bronchopneumonia or.

There may be abdominal syndrome:

• anorexia,
• abdominal pain,
• nausea,
• vomit,

Complications

In the absence of adequate therapy at various times from the onset of the disease (even on days 2-3), tropical malaria in non-immune people acquires a malignant course and a complication develops that threatens the patient’s life.

Possible complications may be based on the following pathophysiological syndromes:

• swelling of the brain and lungs,
• acute renal failure,
• acute intravascular hemolysis,
• hemorrhagic syndrome,
• acute adrenal insufficiency,
• overhydration,
• toxic effects of specific drugs...

Clinically, in patients with tropical malaria, a malignant attack can manifest itself:

• malarial coma (cerebral malaria);
• acute intravascular hemolysis;
• acute renal failure (acute tubular necrosis, immune complex nephritis),
• hypoglycemia;
• pulmonary edema (excessive fluid administration);
• hemoglobinuric fever.

Laboratory diagnosis of the disease consists of detecting plasmodia in the patient’s blood by microscopy.

Treatment: injections and tablets for malaria

The drug of choice for the treatment of patients with malarial coma and severe forms of tropical malaria is dihydrochloride tablets and its analogues, as well as solutions of the drug.

Also, if it is not possible to give the patient anti-malaria tablets, an alternative drug, chloroquine, is used for parenteral administration. The drugs are administered parenterally until vomiting stops and the patient emerges from an unconscious state, taking into account the duration of the drug, single and daily dose. The drugs are administered in a 5% glucose solution. Infusions are repeated every 4-6 hours. The volume of injected fluid should not exceed 2-3 liters per day and strictly correspond to the amount of injected fluid. When treating patients with malarial coma, it is necessary to provide oxygen therapy, combat toxicosis, cerebral hypertension, cerebral edema and possible renal failure. A study of it is mandatory if a malarial coma is suspected.

Malaria - symptoms and treatment

What is malaria? We will discuss the causes, diagnosis and treatment methods in the article by Dr. P.A. Aleksandrov, an infectious disease specialist with 12 years of experience.

Definition of disease. Causes of the disease

Malaria (febris intermittens, swamp fever) is a group of protozoal vector-borne human diseases caused by pathogens of the genus transmitted by mosquitoes of the genus Anopheles and affecting elements of the reticulohistiocytic system and erythrocytes.

Clinically characterized by a syndrome of general infectious intoxication in the form of febrile paroxysms, enlarged liver and spleen, as well as anemia. In the absence of urgent, highly effective treatment, serious complications and death are possible.

Etiology

Type - protozoa ( Protozoa)

Class - sporozoans ( Sporozoa)

Order - Haemosporidium ( Haemosporidia)

Family - Plasmodidae

Genus -

• P. malariae(quartan);
• P. falciparum(tropical malaria) - the most dangerous;
• P. vivax(three-day malaria);
• P. ovale(ovale malaria);
• P. knowlesi(zoonotic malaria of Southeast Asia).

Duration of exoerythrocytic schizogony (tissue reproduction):

• P. falciparum- 6 days, P. malariae- 15 days (tachysporozoites - development after a short incubation);
• P. ovale- 9 days, P. Vivax- 8 days (bradysporozoites - development of the disease after long-term incubation);

Duration of erythrocyte schizogony (reproduction in erythrocytes, that is, in the blood):

Epidemiology

The specific carrier is a mosquito of the genus Anopheles(more than 400 species), which is the final host of the infectious agent. Man is only an intermediate host. Mosquitoes are active in the evening and at night. The availability of water plays an important role, so the greatest spread of infection is observed in humid places or during the rainy season.

Transmission mechanism:

• transmissible (inoculation - bite);
• vertical (transplacental from mother to fetus, during childbirth);
• parenteral route (blood transfusion, organ transplantation).

The spread of malaria is possible if you have:

1. source of infection;
2. carrier;
3. favorable climatic conditions: the ambient air temperature must be constantly at least 16°C and continuous for 30 days - this condition is dominant in the geographic area of ​​the possible spread of malaria (for example, in the central zone of the Russian Federation such climatic conditions are practically impossible).

If you notice similar symptoms, consult your doctor. Do not self-medicate - it is dangerous for your health!

It starts off sharp.

The incubation period depends on the type of pathogen:

• three-day - 10-21 days (sometimes 6-13 months);
• four-day - 21-40 days;
• tropical - 8-16 days (sometimes a month for intravenous infection, for example, through blood transfusion);
• ovale malaria - 2-16 days (rarely up to 2 years).

The main syndrome of the disease is a specific general infectious intoxication, which occurs in the form malarial attack. It begins more often in the first half of the day with a change in phases of chills, heat and sweat. Sometimes preceded by a prodrome (malaise). The attack begins with chills, the patient cannot warm up, the skin becomes pale, cold to the touch and rough (duration - 20-60 minutes). During this time, a person loses up to 6000 kcal. Then the fever begins (body temperature rises to 40°C within 2-4 hours). Then comes a period of increased sweating (body temperature decreases, overall health improves). During the interictal period, a person’s well-being can be described as a “after the banquet” state. Then everything repeats again.

Upon examination, various degrees of depression of consciousness can be revealed (based on the severity of the disease). The patient's position also corresponds to the severity of the disease. Soreness of muscles and joints appears; during an attack there is some variability in the appearance of the skin depending on the type of pathogen:

• with three-day malaria - pallor with chills and red hot skin with fever;
• with tropical malaria - pale, dry skin;
• with a four-day illness - gradual development of pallor.

Peripheral lymph nodes do not enlarge. The cardiovascular system is characterized by tachycardia, low blood pressure, and with four-day malaria there is a “spinning top” noise and muffled tones. Dry wheezing, tachypnea (rapid shallow breathing), increased respiratory rate, and dry cough are heard in the lungs. In severe cases, pathological types of breathing appear. From the gastrointestinal tract, there is a decrease in appetite, nausea, vomiting, bloating and enteritis syndrome (inflammation of the small intestine), hepatolienal syndrome (enlarged liver and spleen). The urine often turns dark.

Clinical criteria for malaria:

Pathogenesis of malaria

Mosquitoes of various species of the genus Anopheles When drinking the blood of a sick person (with the exception of zoonotic malaria), they allow the patient’s blood to enter their stomach, where the sexual forms of plasmodium - male and female gametocytes - enter. The progress of sporogony (sexual development) culminates in the formation of many thousands of sporozoites, which, in turn, accumulate in significant quantities in the salivary glands of the mosquito. Thus, the blood-sucking mosquito becomes a source of danger to humans and remains infectious for up to 1-1.5 months. Infection of a susceptible person occurs through the bite of an infected (and contagious) mosquito.

Next, the sporozoites, through the blood and lymph flow (stay in the blood for about 40 minutes), penetrate into the liver cells, where their tissue schizogony (asexual reproduction) occurs and merozoites are formed. During this period, clinical well-being is observed. Subsequently, with tropical and quartan malaria, merozoites completely leave the liver, and with tertian and oval malaria they can reside in hepatocytes for a long time.

Development of hemoglobinuric fever (black water fever) is associated with massive intravascular hemolysis (destruction of red blood cells with the release of hemoglobin) and deficiency of glucose-6-phosphate dehydrogenase in red blood cells (shock kidney).

Malarial encephalitis develops when erythrocytes stick together in the capillaries of the brain and kidneys with the formation of erythrocyte blood clots, which, together with the general process, leads to increased permeability of the vascular walls, release of plasma into the extravascular bed and cerebral edema.

Malaria in pregnant women It is very difficult, with frequent development of complications; malignant malaria syndrome is characteristic. Mortality, compared to non-pregnant women, is 10 times higher. When the mother becomes ill in the first trimester, there is a significant increase in the risk of abortion and fetal death. Intrauterine infection is possible, leading to developmental delays and clinical and laboratory signs of malaria in a newborn.

Differential diagnosis:

Classification and stages of development of malaria

By severity:

• light;
• moderate;
• heavy.

By form:

• typical;
• atypical.

For complications:

Complications of malaria

Diagnosis of malaria

The basis of laboratory diagnosis of malaria is microscopy of blood using the thick drop method (detection of malarial plasmodium) and thin smear (more accurate determination of the type of plasmodium). If malaria is suspected, the test should be repeated up to three times, regardless of the presence of fever or apyrexia.

The following studies are being carried out:

Treatment of malaria

The location is the infectious diseases department of the hospital.

It is necessary to use antimalarial drugs based on the availability of data on the possibility of malaria (if a method of etiological confirmation is unavailable and there is a high probability of malaria, treatment must be prescribed), and determination of the type of plasmodium.

Based on the patient’s condition and manifestations of the disease, a complex of pathogenetic and symptomatic therapy is prescribed.

At the slightest sign of malaria (fever, chills after visiting southern countries), you should immediately visit a doctor or call an ambulance. Self-medication is life-threatening.

Forecast. Prevention

With timely treatment and the absence of complications, complete recovery most often occurs. With delayed treatment (especially in Europeans) and the development of complications, the prognosis is unfavorable.

The basis of prevention is the fight against vectors of infection. This includes the use of insecticide-impregnated mosquito nets, indoor use of insecticide repellent sprays, and chemoprophylaxis against malaria. It is also quite effective to drain swamps, lowlands and deprive mosquitoes of their natural environment. Travelers should not be outside sheltered residential premises at night, especially outside cities.

A number of antimalarial vaccines are used, for example RTS,S/AS01 (Mosquirix™), but its use is still limited, since its effect provides only partial protection in children (possible use in children in particularly dangerous areas of Africa).