Malaria Paludisme, Paludismo, МаларияMalaria is the world’s most important parasitic disease.
Distribution• Malaria-endemic countries- more than 100 countries inAfrica, Asia, Oceania, Southand Central America, someof the Caribes.Malaria-endemic countriesare among the poorest in theworld.• More than a third of theworld’s population (about 2billion people) live inmalaria-endemic areas and 1billion people are estimatedto carry parasites at any onetime. Mortality• In Africa alone, there are • Annual malaria mortality range from 0.5 to 3 million people.an estimated 200-450million cases of fever in Malaria-related mortality is particularly difficult to measurechildren with malaria each because the symptoms of the disease are non-specificyear. and most deaths occur at home. • Despite global economic development, more people die from malaria nowadays than 40 years ago.
World situation• During the “eradication era”, half a centuryage, malaria was eliminated or effectivelysuppressed in many parts of the world,particularly subtropical regions. • Malaria is now on the rise again;since it is appearing in areas where it haddisappeared, it is classified by some as a re-emerging disease.• WHO dates: Malaria in Europe region - 10countries:Тurkey, Аzerbaijan, Аrmenia, Таdjekistan,Grusia, Uzbekistan, Каzakhstan, Кyrgystan,Тurkmenistan, Russia • Use of ineffective drugs for a potentiallylethal disease will inevitably result in anincrease in mortality. Development ofresistance to antimalarial drugs had resultedin a four to eight fold increase in mortality.
Etiology and pathogenesisFour species of the genus Plasmodium cause nearly all infections inhumans. These are Plasmodium vivax, Plasmodium ovale, Plasmodiummalariae, and Plasmodium falciparum.P. falciparum predominates in Africa, New Guinea, and Haiti;P. vivax is more common in Central America and the Indiansubcontinent. The prevalence of these two species is approximatelyequal in South America, eastern Asia, and Oceania.P. malariae is found in most endemic areas, especially throughoutsub-Saharan Africa, but is much less common.P. ovale is relatively unusual outside Africa.
VectorVarious species of anopheline mosquitoesare definitive hosts of malarial parasites• An. Maculipenis,• An. Superpictus,• An. Elutus ets.
Bilogical Cycle of parasites Human infection begins when a female anopheline mosquito inoculates plasmodial sporozoites from its salivary gland during a blood meal
When the female mosquito bites an infected person, she draws into her stomach blood that may contain gametocytes – male end female.• In mosquito glend of the developmental cycle depends not only on the species of Plasmodium, but on the particular mosquito host and the ambient temperature (more than 16ºC).
• These microscopic forms of the malarial parasite are carried rapidly via the bloodstream to the liver, where they invade hepatic parenchymal cells and begin a period of asexual reproduction.• By this amplification process (known as intrahepatic or prerythrocytic schizogony or merogony), a single sporozoite eventually produces thousands of daughter merozoites.• The swollen liver cell eventually bursts, discharging motile merozoites into the bloodstream; at this point the symptomatic stage of the infection begins.• These microscopic forms of the malarial parasite are carried rapidly via the bloodstream to the liver, where they invade hepatic parenchymal cells and begin a period of asexual reproduction.• By this amplification process (known as intrahepatic or prerythrocytic schizogony or merogony), a single sporozoite eventually produces thousands of daughter merozoites.
• By the end of the 48-h intraerythrocytic life cycle (72 h for P. malariae), the parasite has consumed nearly all the hemoglobin and grown to occupy most of the red cell. Multiple nuclear divisions take place (schizogony or merogony), and the red cell ruptures to release 6 to 30 daughter merozoites, each capable of invading a new red cell and repeating the cycle. The disease in human beings is caused by the direct effects of red cell invasion and destruction by the asexual parasite and the hosts reaction. During this process, some parasites develop into morphologically distinct sexual forms (gametocytes, still within the erythrocytes), which are long-lived.
• Thus the infected erythrocytes sequester inside the small blood vessels.• At the same stage, these P. falciparum-infected red cells may also adhere to uninfected red cells to form rosettes. The processes of cytoadherence and rosetting are central to the pathogenesis of falciparum malaria. They result in the sequestration of red cells containing mature forms of the parasite in vital organs (particularly the brain and heart), where they interfere with microcirculatory flow and metabolism. only the younger ring forms of the asexual parasites are seen in the peripheral blood in falciparum malaria.• In the other three "benign" malarias, sequestration does not occur, and all stages of the parasites development are evident on peripheral blood smears. Whereas P. vivax, P. ovale, and P. malariae show a marked predilection for either old red cells or reticulocytes and produce a level of parasitemia seldom exceeding 2 percent, P. falciparum can invade erythrocytes of all ages and may be associated with very high levels of parasitemia.
Clinical featuresIncubating period - 9 до 60 daysP. vivax – 10 - 21 days, 8–14 months (P. vivax hibernans)P. ovale – 11 - 16 daysP. falciparum – 9 - 16 daysP. malariae – 28 - 60 daysThe first symptoms of malaria are nonspecific – the lack of a sense of well-being, headache, fatigue, abdominal discomfort, and muscle aches, anorecia, subfebril period, in children diarrhea , followed by fever are all similar to the symptoms of a minor viral illness.This Prodromal period is 3-5 days.In some instances, a prominence of headache, chest pain, abdominal pain, arthralgia, myalgia, or diarrhea may suggest another diagnosis.
Clinical features Malarial paroxysm1. Fever - trembelling, tachicardia (1/2 - 2 hours);2. Febrile period - 38 - 41 С, 4-6 hours, nausea, headache, tahipnoea, myalgia, a rthralgia, convulsions, lose consciousness3. Sweating - after fast fall of temperature (1-2 h)
• Start of malarial fever - on day ( 09 - 15 h) - Ovale malaria - usually evening• Periodicity:- 48 h – invasion with P. vivax и P.ovale- 36- 48 h, or every day – invasion with P. falciparum- 72 h – P. malariae• The classic malarial paroxysms, in which fever spikes, chills, and rigors occur at regular intervals, suggest infection with P. vivax or P. ovale.• The fever is irregular at first (that of falciparum malaria may never become regular). The temperature of nonimmune individuals and children often rises above 40ºC in conjunction with tachycardia and sometimes delirium.• Liver enlargement – in first days of desease
• Splenic enlargement, mild jaundice may develop in patients with otherwise - uncomplicated falciparum malaria and usually resolves over 1 to 3 weeks. Severe Falciparum malaria Cerebral malaria• Coma is a characteristic and ominous feature of falciparum malaria and, despite treatment, is associated with death rates of approximately 20 % among adults and 15 among children.• - Cerebral malaria manifests as diffuse symmetric encephalopathy; focal neurologic signs are unusual.
• Cerebral malaria manifests as diffuse symmetric encephalopathy; focal neurologic signs are unusual. Although some passive resistance to head flexion may be detected, signs of meningeal irritation are lacking. Approximately 15 % of patients have retinal hemorrhages. Fewer than 5 % have significant bleeding Convulsions usually generalized and often repeated, are common, particularly among children with cerebral malaria. Whereas adults rarely suffer neurologic sequelae, approximately 10 % of children surviving cerebral malaria especially those with hypoglycemia, severe anemia, repeated seizures, and deep coma have some residual neurologic deficit when they regain consciousness.• Pulmonary Edema (Noncardiogenic) Adults with severe falciparum malaria may develop noncardiogenic pulmonary edema even after several days of antimalarial therapy. Mortality is over 80 %. This condition can be aggravated by overly vigorous administration of intravenous fluid. Renal Impairment Renal impairment is common among adults with severe falciparum malaria but rare among children. The pathogenesis of renal failure is unclear but may be related to parasitized-erythrocyte sequestration interfering with renal microcirculatory flow Mortality in the initial phase of hypercatabolic acute renal failure is high; in survivors, urine flow resumes in a median of 4 days, and serum creatinine levels return to normal in a mean of 17 days Dialysis considerably enhances the likelihood of a patients survival.• Hematologic Abnormalities Anemia results from accelerated red cell destruction and removal by the spleen in conjunction with ineffective erythropoiesis. In severe malaria in nonimmune individuals and in areas with unstable transmission, anemia can develop rapidly and transfusion is often required. In many areas of Africa, children may develop severe anemia due to repeated malarial infections. This is a common consequence of continued infection resulting from treatment with chloroquine (or other drugs) to which the parasites are resistant.
• In Pregnancy Falciparum malaria is an important cause of fetal death. In hyper- and holoendemic areas, malaria in primigravida and secundigravida is associated with infected mothers remain asymptomatic despite intense parasitization of the placenta due to sequestration of parasitized erythrocytes in the placental microcirculation.• Congenital malaria occurs in fewer than 5 % of newborns whose mothers are infected and is related directly to the parasitic density in maternal blood and in the placenta.• Malaria In Children Most of the estimated 1 to 3 million persons who die of falciparum malaria each year are young African children. Convulsions, coma, hypoglycemia, metabolic acidosis, and severe anemia are relatively common among children with severe malaria, whereas deep jaundice, acute renal failure, and acute pulmonary edema are unusual.• Chronic complications of malaria• Tropical Splenomegaly (Hyperreactive Malarial Splenomegaly) Chronic or repeated malarial infections produce hypergammaglobulinemia; normochromic, normocytic anemia; and in certain situations splenomegaly.• Some residents of malaria - endemic areas in tropical Africa and Asia exhibit an abnormal immunologic response to repeated infections that is characterized by massive splenomegaly, hepatomegaly marked elevations in serum titers of IgM and malarial antibody
• Quartan Malarial Nephropathy Chronic or repeated infections with P. malariae may cause soluble immune-complex injury to the renal glomeruli, resulting in the nephrotic syndrome. Other, unidentified factors must contribute to this process since only a very small proportion of infected patients develop renal disease.• Recrudescens of malaria develops in:• - Patients with P. falciparum without radical Therapy• - Resistent P. falciparum to 4-AQ• - Patients with P. vivax and P. ovale without Primaquine ThR Relapses are: short-time – after 1 month; late – after 2 or more mths• Asimptomic carrier
DIAGNOSIS• The diagnosis of malaria rests on the demonstration of asexual forms of the parasite in peripheral blood smears subjected to Romanovsky staining. Giemsa at pH 7.2 is preferred.• Both thin and thick blood smears should be examined.• The level of parasitemia is expressed as the number of parasitized erythrocytes among 1000 cells. The relation between parasitemia and prognosis is complex; in general, patients with more than 105 parasites per microliter are at increased risk of dying, but nonimmune patients may die with much lower counts.• A poor prognosis is indicated by a predominance of more mature P. falciparum parasites (i.e., more than 20 percent of parasites with visible pigment) or circulating schizonts in the peripheral blood film or by the presence of phagocytosed malarial pigment in more than 5% of neutrophils.
Laboratory Findings• Normochromic, normocytic anemia is usually documented.• The leukocyte count is generally low to normal, although it may be raised in very severe infections.• The platelet count is usually reduced to about 105 per microliter. Severe infections may be accompanied by prolonged prothrombin and partial thromboplastin times and by especially severe thrombocytopenia• Findings in severe malaria may include metabolic acidosis,• with low plasma concentrations of:• glucose, sodium, bicarbonate, calcium, phosphate, and albumin together with elevations in lactate, blood urea creatinine, urate, muscle and liver enzymes, and conjugated and unconjugated bilirubin.
Treatment1. Blood schizonticides2. Tissue schizonticides of P. vivax и P. ovale3. Gametocyticides1. Blood schizonticides1. 4-aminoquinolines (4-АQ): diphosphates - Chloroquin, Arthrochin, Resochin, Delagil, Aralen sulphates - Nivaquin Chloroquine – total doses 25-30 mg./kg., 1,5 g. 3 days, 1 day - 0,900 g. (I-st dose 0,600 g., after 6-8 h 0,300 g.), 2 и 3-ти day – x 0,300 g. Children – total dose: 25 mg/kg, 1 days 10 mg/kg, after 6-8 h 5 mg/kg, 2 и 3-th day x 5 mg/kg.2. Pyrimethamine (Tindurin, Daraprim) tb. 25 mg, 2 / day3. Sulfonamides - Sulfadoxin tb. 0,250 g, Sulfalene tb 0,250 g4. Quinoline methanols - Mefloquine (Lariam) tb 0,250 g5. Phenanthrine ethanols - Halfan (Halophantrin)6. Antibiotics – Tetracycline, Doxycycline (Vibramycin)7. Combined medicine:• Fansidar (Sulfadoxin + Pyrimethamin) tb. 0,5 g. 3 tb. eднокр.,• Fansimef (Sulfadoxin+Mefloquine+Pyrimethamine) tb.0,775 g, 3 tb.8. Artemisin (Qinghaosu) 10 mg/kg, 3 days, Artemether, Paluther, Artesunat9. Sinthetic – Pyronaridine и др.
The drug of choice for treatment of Resistant falciparum malaria are:- Quinine (sulphuricum/dihydrochloricum ) tb.0,200 g.600 mg every 8 ч., 7 days + Tetracycline 250 mg/6h, 7 days, Children- 10 mg/kg every 8 h, 3-7 days;- Mefloquin tb. 0,250 gr, 15 mg/kg. immune person and 25 mg/kg non-immune, max. dose 1 g, in 2 dose after 6 h.Therapy in patients who are unable to take the oral drug:I.V. - Chloroquine (diphosphate или sulfate) 10 mg/kg в 10 ml/kg isotonic fluid (or amp. 5% sol. Chloroquine diphosphate – 0,2 ml/kg), very slow - for 4 h, second dose 5 mg/kg after 8 h, total dose 25 mg/kgI.M. - Chloroquine 2,5 mg/kg every 4 h or subcutan - 3,5 mg/kg every 6 h till total dose 25 mg/kg.I.V. - Chininum dihydrochloridum amp 2 ml. 300 mg base in 1 ml in adults and children: 10 mg/kg in 10 ml/kg 5% Glucose for 4 h, second infussion after 8- 12 h. In pregnancy – the risk to the fetus of severe falciparum malaria greatly outweighs the possible risk of quinine therapy2. Tissue schizonticides of P. vivax и P. ovale (effective against tissue schisonts)• 8-aminoquinolines (8-АQ) – Primaquine 15 mg / day, 14 days, per os; in G- 6-PD deficient - 7,5 mg/kg/ week, 8 weeks• in patients with deffisancy of G6PD develop intravasals hemolisis• Children > 1 years – 0,25 mg/kg/day, 14 days.3. Gametocyticides - Primaquine for all species of human malarial paracites• Chloroquine and amodiaquine – effective against the gametocytes of p. vivax, p. ovale, p. malariae but do not affect p. falciparum
PREVENTIONIn most of the tropics, the eradication of malaria is not feasible because of the widespread distribution of Anopheles breeding sites, the great number of infected persons, and inadequacies in resources, infrastructure, and control programs.• Where is possible, the disease is contained by judicious use of insecticides to kill the mosquito vector, rapid diagnosis and appropriate patient management, and administration of chemoprophylaxis to high-risk groups.• No safe, effective, long- acting vaccine is likely to be available for general use in the near future.
Personal Protection Against malaria•Simple measures to reduce the frequency of mosquito bites in malarious areas are veryimportant. These measures include the avoidance of exposure to mosquitoes at their peakfeeding times (usually dusk and dawn) and the use of insect repellents, suitable clothing,and insecticide-impregnated bed nets. Widespread use of bed nets, particularly thosetreated with permethrin (a residual pyrethroid), often reduces the incidence of malariaand has recently been shown to reduce mortality in western and eastern Africa.•Antimalarial prophylaxis. Travelers should start taking antimalarial drugs at least 1week before departure so that any untoward reactions can be detected and therapeuticantimalarial blood concentrations will be present when needed. Antimalarial prophylaxisshould continue for 4 weeks after the traveler has left the endemic area.•Mefloquine has become the antimalarial prophylactic agent of choice for much of thetropics because it is usually effective against multidrug-resistant falciparum malaria andis reasonably well tolerated.•Chloroquine 300 mg, деца 5 mg/kg./week, 1 week before travel•Fansidar – 1 tb./ 1 week before travel, 4-6 weeks after coming back x 2 tb./2 weeks•Mefloquine - x 1 tb./ week for adults and children above 45 kg•Proguanil ( Paludrin ) tb. 100 mg. (in pregnancy) - 200 mg/day, in children: <1 years -25mg, 1-4 years - 50 mg, 5-8 years -100 mg, 9-14 years -150 mg/day•Pyrimethamine - 2 tb./ week