MALARIA

Malaria is an infectious disease caused by malarial plasmodia; Characterized by periodic attacks of fever, increased liver and spleen, anemia, recurrent course. The spread of malaria is limited by the area of ​​the mosquitoes of the genus Anopheles and the temperature of the environment, which ensures the completion of the development of the pathogen in the mosquito, ie 64 ° north and 33 ° south latitude; The disease is common in Africa, South-East Asia and South America. In Russia, mainly imported cases are recorded.

The causative agents of malaria are the simplest kind of plasmodia. In humans, plasmodia of four species are parasitized: Plasmodium vivax, P. oyale, P. malariae, P. falciparum. The most widespread is P. vivax, since it is capable of developing in a carrier at a lower temperature than plasmodia of other species. The life cycle of malaria pathogens includes two hosts: a human and a mosquito. In the body of the mosquito-carrier plasmodia pass sexual development (sexual process and sporogony), in the human body, asexual development (schizogony). A mosquito, feeding on the blood of a patient with malaria (or parasite carrier), swallows plasmodia. In the insect's stomach, asexual stages of parasites are digested, and sexual gametocytes are fertilized and undergo a series of transformations, resulting in sporozoites accumulating in the salivary glands of the mosquito-carrier. With subsequent feeding on humans, a mosquito with saliva introduces sporozoites into his body, where the schizogony process takes place. Blood and lymph sporozoites are entered into the human liver, and tissue (exoerythrocytic) schizogony is carried out in its cells - hepatocytes, resulting in the development of exoerythrocytic trophozoites, and then schizonts. Schizonts grow rapidly, their nuclei divide many times, and as a result, from 10,000 to 40,000 merozoites are formed, which leave the hepatocytes, attach to the erythrocyte, and are introduced into it. The duration of tissue schizogony in P. falciparum is 6-8 days, in P. vi-vax-8-10 days, in R. ovale-9-10 days and in P. malariae - 15-20 days.

The source of pathogens is a sick person or parasite carrier, in the blood of which there are gametocytes. Carriers of the pathogen are female mosquitoes of the genus Anopheles. Perhaps intrauterine infection of the fetus through the placenta or in the process of delivery, as well as infection with blood transfusion obtained from parasites.

The clinical picture of the disease is largely due to the type of pathogen, therefore, four forms of malaria are distinguished: a three-day, caused by P. vivax; Oval-malaria, the causative agent of which is P. ovale; Four-day period, due to P. malariae; Tropical, pathogen - P. falciparum. However, a number of clinical manifestations of the disease are common to all forms. The duration of the incubation period depends on the type of pathogen. With tropical malaria, it is 6-16 days, with a three-day period with a short incubation period - 7-21 days (with a long incubation - 8-14 months), with oval malaria - 7-20 days (in some cases 8-14 months) , Four days - 14 - 42 days. At the onset of the disease, there may be a prodroma period, manifested by malaise, drowsiness, headache, body aches, remittent fever. After 3-4 days there is an attack of malaria, during which three periods are distinguished - chills, fever, profuse sweating.

The first period can be expressed in varying degrees: from easy cognition to tremendous chills. The face and limbs become cold, cyanotic. The pulse is quick, the breath is shallow. The duration of chills from 30 - 60 minutes to 2 - 3 hours. During the heat, lasting from several hours to 1 day or more, depending on the type of pathogen, the general condition of patients worsens. The temperature reaches high figures (40-41 ° C), the face turns red, dyspnea , excitement, often vomiting . The headache is worse. Sometimes there is delirium , confusion, collapse . Possible diarrhea. The end of the attack is characterized by a drop in temperature to normal or subnormal digits and increased sweating (the third period), lasting 2-5 hours. Then comes a deep sleep. In general, the attack usually lasts 6-10 hours. Later, during a different time, depending on the type of pathogen (eg, one day, two days), the normal temperature remains, but the patient experiences weakness, aggravated after each next attack. After 3 to 4 attacks, the liver and spleen increase. At the same time, anemia develops, the skin of the patient acquires a pale yellowish or earthy tinge. Without treatment, the number of seizures can reach 10-12 or more, then they spontaneously cease. However, complete recovery does not occur. After a few weeks, there is a period of early relapse, which by clinical signs is little different from the primary acute manifestations of malaria. After the termination of early relapses with three-day malaria and oval malaria in 8-10 months (and later), usually in the spring of the year following the infection, late relapses may develop. They flow more easily than the primary disease. In persons taking inadequate antimalarial drugs for preventive purposes, the clinical picture of the disease can be atypical, the incubation period can last several months or even years.

Three-day malaria usually proceeds benignly. The attack begins in the afternoon with a sudden rise in temperature and chills. Attacks occur in one day. There are also daily seizures.

Oval malaria is similar to the three-day period caused by P. vivax, but it is easier. Attacks occur more often in the evening hours.

Four-day malaria, as a rule, has no prodromal period. The disease begins immediately with attacks occurring after 2 days on the third or lasting two consecutive days with one febrile day. Chills are poorly expressed.

Tropical malaria is characterized by the most severe course, it usually starts with prodromal events: for 2 to 3 days before the attack, headache , arthralgia, myalgia, back pain, nausea , vomiting , and diarrhea may appear. Within a few days the fever may be permanent or irregular. In residents of endemic areas with tropical malaria, the temperature is often intermittent. Unlike other forms of malaria, with this form, chills are less pronounced, and the febrile period is longer -12 to 24 and even 36 hours. The periods of normal temperature are short, sweating is not sharp. Already in the first days of the disease, palpation is characterized by soreness in the left hypochondrium, the spleen becomes accessible for palpation after 4-6 days of illness. The liver increases from the first days of illness. Often, jaundice develops, nausea , vomiting , abdominal pain, diarrhea.

Complications are most often observed in tropical malaria; They develop in non-immune individuals and in most cases are associated with high parasitemia (more than 100 thousand in 1 μl of blood). These include cerebral form of the disease (malarial coma), infectious-toxic shock , acute renal failure , pulmonary edema, hemoglobinuria fever .

The diagnosis is made on the basis of a clinical picture (the emergence of characteristic malarial seizures) and epidemiological history (for example, stay in a malaria-poor area in the last 2 years). With tropical malaria, it is often difficult to identify the cyclicity of the course, so it should be suspected in all cases of fever-related illnesses, if there is a corresponding epidemiological history. The decisive role in diagnostics in this case is the detection of the pathogen. A smear and a thick drop of blood are subject to investigation. In the latter parasites, it is easier to detect because of their higher concentration; In the smear the type of pathogen is determined. Blood sampling is performed both during the attack and during the interictal period. A single negative test result does not exclude malaria, repeated studies are needed. An anemia that is one of the characteristic signs of malaria can serve as an aid in diagnosis.

Treatment is carried out in a hospital. Patients are hospitalized in wards, protected from mosquitoes. To eliminate attacks of malaria, hematoschotropic drugs are prescribed, which disastrously affect the asexual erythrocyte stages of the plasmodium. These include chloroquine diphosphate and its analogues from the group of 4-aminoquinolines (hingamin, delagil, resichin, etc.), as well as plakvenil, quinine , bigum, chloride, mefloquine. More often used chloroquine (Delagil). These drugs provide a radical cure for only tropical and four-day malaria. After the elimination of bouts of the three-day and oval-malaria it is necessary to carry out an anti-relapse treatment with primaquine and quinocide.

The prognosis for timely treatment is favorable. With complicated forms of tropical malaria, lethal outcomes are observed, especially in children and pregnant women.

Prevention is aimed at early detection and radical treatment of patients and parasites, as well as in the fight against mosquitoes - carriers of the pathogen of malaria. For early detection of patients and parasites, a blood test is required for all febrile patients who come from malaria-unfriendly terrains. In these areas, it is necessary to use repellents, which are applied to the open parts of the body, to protect mosquitoes from homes by using protective nets on windows and doors, to apply protective canopies over beds. Great importance in the fight against mosquitoes is the elimination of their breeding sites, the improvement of economic-useful reservoirs.

Persons leaving for malaria-endemic areas conduct personal chemoprophylaxis. One week before the exit to the malaria focus, dojagil (or hingamin) is given 0.25 g 2 times. Then the drug is taken in the same dose during the entire stay in the hearth and 4 to 6 weeks after returning 1 time per week.

Those who have been ill with malaria for 2 years are under clinical supervision, which includes clinical observation and inspection for carriage of plasmodia.