INFECTIOUS DISEASES : MALARIA (MARSH FEVER, PALUDISM) (MALARIA) - etiology, pathogenesis, symptoms and course of, recognition, prediction and prevention
Etiology. The causative agent of malaria - malaria Plasmodium has a complex cycle of reproduction, disintegrating sexual (sporogony)flowing in mosquitoes of the genus Anopheles, and asexual (schizogony)occurring in man. Types of parasites:
1) Plasmodium vivax - pathogen malariae tertianae, tertian malaria,
2) Plasmodium malariae - pathogen malariae quartanae,
3) Plasmodium falciparum is the causative agent malariae tropicae - tropical malaria?
4) Plasmodium ovale.
Epidemiology is closely associated with vector - mosquitoes of the genus Anopheles. Malaria is possible only in those places where there are favorable hydrological and climatic conditions for hatching Anopheles, i.e. where there are suitable for hatching ponds and where the temperature during the summer season provides the breeding of mosquitoes and the development of Plasmodium (12 - 15 ° ). The reservoir of the virus, which infected mosquitoes, is a sick man. Fresh malaria is possible in the presence of two factors: the carrier of gametocytes and the mosquito vector. The importance of six species of Anopheles mosquitoes: An. claviger (maculipennis), An. bifurcatus, An. superpictus) in Tajikistan, An. hyrcanus (pseu - dopictus), An. pulcherrimus and An. plumbeus (nigripes). As the breeding of mosquitoes is closely associated with water, and water factor plays in the epidemiology of malaria dominant role. In malarial areas should carefully study the regime of rivers associated with the spring floods, leaving after spadine extensive water reservoirs. Damage and technical deficiencies in the irrigation systems create artificial swamps. Along with abundant water, play an important role, and small ponds: small space between the pebbles of the mountain rivers, the marks of the hoofs, etc., May vypaivanie mosquitoes in artificial reservoirs - in barrels, tanks, etc., Domestic animals (horses, cows) to distract mosquitoes (especially'an. maculipennis) on itself and thereby reduce the possibility of human infection. Susceptibility to malaria seems to be almost universal, innate immunity unit. The increase in the number of fresh diseases associated with the summer season (when the three-day form with spring, see below). In the beginning of the summer season prevails three-day form, to the end of the season (in the South) dominates malaria tropica in Early spring, long before the departure of mosquitoes (March), increasing the recurrence malariae tertianae, August - relapse malariae tropicae. At registration it is necessary to accurately differentsirovat primary malaria from relapses.
The pathogenesis is closely associated with the biology of the parasite, with cycles of schizogony, and destruction of red blood cells and chronic toxicity of the waste products of Plasmodium. Incubation period cycles of schizogony are the same as in the acute period, but the number of parasites is still insufficient to cause typical reactions. It is possible that plasmodia pre-varicella recorded in endothelial cells (achteruitrijcamera form). The incubation period averages 10 to 14 days, the shortest for tropical forms, and longest for Quartey. When tertian malaria, especially in Northern latitudes, there are often cases with long inkubacji (febrile seizures in the spring when infected the previous summer). Thermal response coincides with the fragmentation of the schizont and mass flow of merozoites into the blood plasma (the chills); while in the blood circulate merozoites, and the products of their activity and destruction of red blood cells, the temperature is kept at a very high figures; as fixation of merozoites into new red blood cells and cleansing the blood flow from alien blood substances fever stops critically with drenching sweat. Therefore, the episodes follow each other with great accuracy every 48 hours during malaria tertianae and tropicae every 72 hours in malaria quartanae. Maturation and crushing PI. falciparum occur in the capillaries of internal organs, which helps to overflow these capillaries affected erythrocytes and upsets the power of the relevant authorities. The very large number of parasites it comes to stasis and blockage of capillaries. This property P1. falciparum is explained in more severe tropical malaria (malaria perniciosa). In all forms of malaria with each new attack increases the number of parasites by dividing the schizont on the merozoite and the accumulation of sexual forms (macro - and microgametocytes), and therefore increases the possibility of infection vectors. On the other hand, a huge number of merozoites dies, asexual reproduction leads to the degeneration of the pathogen, and in the body of the patient, the accumulation of antibodies, the nature of which is uncertain. As a result of these complex and not fully explored the relationship of the pathogen and microorganism attacks can be stopped and without treatment, but the steady-state condition is very unstable. Although cessation of attacks comes latent period and gradually disappear, the symptoms of the disease (enlargement of the spleen and liver, weight loss, changes in the blood picture) and parasites are not detected in the blood, yet recurrent seizures related to natural manifestations of malaria. The cause was due to the recovery of the latent schizogony, and continuing during the absence of attacks, but quantitatively insufficient for the manifestation of the body of febrile reactions. Recently put forward a new hypothesis explaining the recurrence is not the activation of schizogony, and blood gets preserved with the incubation period Exo-erythrocytic forms, giving rise to a new cycle of schizogony. When artificial infection of humans with the blood of a patient with malaria (schizonts) relapses do not occur; if the infection through mosquito (sporozoites) relapses usually occur. While fresh and recurrent seizures in the patient developed two parallel processes: 1) the growth of anemia due to destruction of red blood cells (anisoles, poikilocytes, polychromasia and basophilic punctate erythrocytes) and 2) the accumulation of decay products and the activity of parasites and pigment, gradually blocking the reticulo-endothelial system (indicator of its stimulation monocytosis). The pigment is formed from disintegrated cells; it fills the spleen, bone marrow, copperhouse liver cells, endothelium of blood vessels of internal organs. Spleen increases sharply, pulp hyperplasias capsule thickens. The liver also swells up pigment. Significant accumulations of pigment are formed in all internal organs, but particularly important are changes in the brain: the pigmentation of bark, small hemorrhages, and in tropical form - the formation of small necrotic nests, surrounded by a ring glioznogo cells, surrounded in turn area of hemorrhages. Comparison of these data with the above paintings capillary stasis shows that malaria is a deep defeat the entire body, affecting the function of all organs, of which the most vulnerable is the brain (comatose). The duration of malaria according to modern views: a three-day form - 18 - 20 months for tropical forms no more than one year, for four days - up to 3 years and longer. Perennial malaria in endemic foci is the result of recurrent infections.
The fresh symptoms of malaria are very common: seizures, starting sharp chills and then ending, alternate with the correct sequence. Yellow-gray complexion, enlarged spleen. The mixed form irregular fever, but mandatory chills and sweats. When the tropical form of apyrexia very short, often temperature type continua. With the cessation of attacks often persists enlargement of the spleen, liver, weight loss, changes in the blood picture: anisoles, poikilocytes, polychromasia, biophilia punctate, leukopenia with lymph and monocytosis.
For. The alternation of malaria attacks in the various forms described above. Duration of attacks malariae tertianae and quartanae - 8 - 12 hours, malariae tropicae - up to 36 hours; for the latter form is characterized by a small remission on top of the temperature wave. The attack is divided PA three stages:
1) chill - paleness of the face, goose bumps, shivering to knock the teeth;
2) heat - hyperemia of the face, injection of the sclera, the temperature to 40 to 41º;
3) pot with a critical temperature drop to normal.
Combination with tropical form often give the fever a permanent type, which is frequently observed when pure malaria tropica. No apyrexia due to insufficient thermometry, not registering the temperature drop at night (to measure the temperature every 3 hours). The first attacks even malariae tertianae can be greater length (stretched), but later become typical. The most early and constantly react spleen and liver. The earlier you start specific treatment, the faster end phase of fresh attacks. Without treatment after 7 to 8 days in the blood are detected gametocytes n increases the number of schizonts and related Sithonia anemia. The most severe course gives malaria tropica (the duration of the attack, a large number of parasites, the effects on the internal organs and the Central nervous system). In malaria foci during acute attacks may be significantly delayed, or seizures repeated again after their termination due to re-infections. Such cases occur during the malaria season, but there are also so-called long form, in which attacks are reiterated, once stopped the treatment, and outside the malaria season. When spontaneous termination of attacks possible early recurrence (1 - 2 attack). Most often treatment cuts off the attacks for a long time. Late relapses appear when malaria tertiana in the spring, when malaria tropica in late summer. Recurrent attacks appear not later than one year after the latest of the disease; later attacks should be viewed as a reinfection. For recurrent attacks similar to the primary, the more likely they are easier. Sometimes for a few days to relapse can be detected in the blood of plasmodia. Relapses can occur at an inopportune time for them, under the influence of various effects on the body of the patient (cooling, physical fatigue, overheating, subcutaneous inoculations, vaccines, surgical intervention). Special forms of malaria include:
1) typhoid with constant temperature, delusions (often malaria tropica);
2) gasrointestinal flowing type of diseases with high fever, diarrhea and vomiting; in some cases the picture cholerophobia Algida (for group diseases not forget about the possibility salmonelloses etiology);
3) disinterestedly (usually a combination of malaria dysentery);
4) icteric, with pronounced jaundice and content of bilirubin in the blood serum of 4 mg% and above; in the presence of parenchymatous hepatitis and skin hemorrhages may be combined with lepto - spiroton (see Disease Vasiliev-Weyl);
5) appendicectomy, so mimicking acute appendicitis that sometimes patients undergo surgery;
6) comatose - the most severe form (malaria tropica); there are two forms: aporosa (precoma) - in patients with drowsy periodic enlightenment of consciousness and deep coma with a full prostration, meningo-encephalitides symptoms, tachycardia, fall in blood pressure, acceleration ROHE up to 60 - 70 mm per hour, and forms the dividing PI. falciparum in the peripheral blood;
7) atlanticheskaya form - mainly in children.
Complications. Blackwater fever develops with long flowing malaria in connection with the methods of quinine. Sharp temperature rise, emerging hemolytic jaundice, sudden loss of strength, urine temnoburogo color (hemoglobinuria, albuminuria, urobilinuria) as a result of the rapid destruction of red blood cells (hemoglobin 15 - 20%, red blood cells up to 1 000 000), enlarged liver and spleen, persistent vomiting. Malarial cachexia, ascites, edema have been observed at many times Sarajevska and accompanied by splenomegaly, liver cirrhosis. Develop in persons, malnourished, suffering from concomitant diseases or pathological conditions that prevent the development of immunity, normal for the residents of endemic foci (decrease with age and parasitic splenic index).
Acute attacks of malaria can easily be mixed with many diseases in the subtropics, in particular, to illness, pappataci return and tick typhus. Typical cases of malaria detected without difficulty. When atypical temperature required fractional thermometry. In the latent period of the attacks can be triggered by: summer: common cold showers in winter hot tub, irradiation with ultraviolet rays, the introduction of adrenaline, bruchnotifosny vaccines, etc. blood test for malaria characteristic radiation with lymph and monocytosis. From erythrocytes - anisoles, poikilocytes, polychromasia and basophilic punctate. For the exact determination of Plasmodium is microscopic examination of blood. For precision and speed is more profitable, osobeno for mass investigations, thick smear method. Other diagnostic methods noteworthy reaction melanophloia with melanin antigen.
1) to the possible limitation of reservoir of the virus and protection from mosquitoes,
2) to the destruction of the carrier elated and larval state associated with the liquidation in breeding sites,
3) to protect people from mosquito bites,
4) to increase resistance to infection in healthy persons.
Fighting parasitologically achieved full registration of persons who have had bouts of malaria over the past year, to be held in respect of these persons relapse treatment (see Treatment) and prevention Ukrainization during the summer season (see below).
The vector control is carried out mainly through larvicide events (neftianie infested waters, their ORGANIZACIJA processing drug DDT, check Gambusia) by destruction of waterlogging; by land reclamation. The destruction of the wings of a mosquito is less effective.
Protecting people from mosquito bites at night is achieved sassettavia residential premises, the supply of lace curtains, wearing mystiqueros and gloves when you stay at night in the open air, equipment, special towers for a night's rest, distraction mosquitoes in domestic animals (horses, cows).
Chemoprophylaxis is carried out in respect of persons suffering from malaria (see above), and in severely affected endemicheski foci and healthy, especially when it is impossible to carry out the whole complex of anti-malarial activities. Chemoprophylaxis among suffering from acute or recurrent malaria over the past year, and found gameconsole is intended primarily to prevent infecting mosquitoes. It is in places highly affected by malaria, with the departure of the first generation of mosquitoes (15/VI - 1/VI) to the time of their reduction in the North to 15/VIII, in middle strip - 1/IX, in the South - to 15/1X - 1/X. Given Akrikhin 2 tablets per day for 2 consecutive days with breaks in 4 to 5 days (1st and 2nd day of the week or one day a two-day intervals. Chemoprophylaxis is healthy in a highly malaria-affected areas. Akrikhin is given 2 days in a row of 0.2 to 3 to 5-day intervals. Biganal (see below) is 0.1 to 2 times a week. Hinn prevention: a) quinine 0,4 daily, b) quinine 0.5 in the first 3 days of the week.