Showing papers on "Malaria published in 1980"

The Garki project: Research on the epidemiology and control of malaria in the Sudan savanna of West Africa

Abstract: The authors examine the epidemiology of malaria in the lowland rural savanna of Sudan using data obtained from a joint study carried out between 1969 and 1976 by the World Health Organization and the government of Nigeria. The measurement and relationship of entomological parasitological and seroimmunological variables are analyzed as are some demographic and clinical variables. A mathematical model of the transmission of malaria is constructed and tested in order to compare alternative control strategies and calculate their expected effects (ANNOTATION)

The Anaemia of P. falciparum Malaria

Abstract: The haematological changes in a group of young Gambian children with P. falciparum malaria have been analysed. In children with acute infection anaemia was most marked during the period after treatment. Although many of these patients developed a positive direct Coombs test during this period of the illness it is not clear whether the anaemia which occurs after treatment has an immune basis. A second group of children showed quite different haematological findings. They appear to have a more chronic form of P. falciparum malaria infection, were profoundly anaemic at presentation, showed gross dyserythropoietic changes in their bone marrows, and had a full reticulocyte response and rise in haemoglobin after treatment. A third group of children were encountered whose haematological abnormalities were intermediate to those of the acute and chronic groups. These findings indicate that the patho-physiological mechanisms responsible for the anaemia of P. falciparum malaria are different at different stages of the illness.

Protective monoclonal antibodies recognising stage-specific merozoite antigens of a rodent malaria parasite.

Abstract: Immunity to malaria is mediated, at least in part, by antibody. Resistance to infection has been passively transferred with immune serum or its immunoglobulin fraction in human1, simian2 and rodent3,4 malaria. However, because of the structural and antigenic complexity of the malaria parasites5,6, it has proved difficult to identify and characterise those parasite antigens against which protective antibody is directed. We have produced several hybrid cell lines secreting monoclonal antibodies against the rodent malaria parasite, Plasmodium yoelii, and we now report that, of the antibodies tested, only those specific for antigens exclusive to the merozoite were protective in passive transfer experiments. Other anti-P. yoelii monoclonal antibodies, apparently recognising antigens in the membrane of the infected erythrocyte, were not protective on passive transfer. The protective monoclonal antibodies should be useful in the isolation of the important antigens of this parasite.

A Longitudinal Study of Human Malaria in the West African Savanna in the Absence of Control Measures: Relationships between Different Plasmodium Species, in Particular P. Falciparum and P. Malariae*

Abstract: The research project on the epidemiology and control of malaria conducted in the Garki District, Kano State, jointly by the Government of Nigeria and the World Health Organization included among its objectives the study of the baseline epidemiology prior to the introduction of any control measures. The present paper analyzes the project's data with respect to the relationships among the three species of Plasmodium present, P. falciparum, P. malariae and P. ovale. Parasitemia with P. falciparum or P. malariae is more likely in the presence than in the absence of the other species. Among persons positive for P. falci- parum, those with a higher density of parasitemia are more likely to have P. malariae also than those with a lower density of P. falciparum parasitemia. There is a pronounced seasonal alternation in prevalence between P. falciparum and P. malariae. The research project on the epidemiology and control of malaria conducted in the Garki District, Kano State, jointly by the Government of Nigeria and the World Health Organization included among its objectives the study of the baseline ep- idemiology prior to the introduction of any control measures. The present paper analyzes the proj- ect's data on prevalence, incidence, and parasite density by season and age, with respect to the relationships among the three species of Plasmo- dium present, P. falciparum, P. malariae and P. ovale.

Relapses in primate malaria: discovery of two populations of exoerythrocytic stages. Preliminary note.

Abstract: In this case conventional investigations4 did not show any aetiological cause for the patient's adverse reaction, but a penicillinase-sensitive penicillin was detected in the donor blood unit. The patient's history, the symptoms that appeared after the injection of cephazolin, and the results of the rat mast-cell degranulation test leave little doubt about the diagnosis of hypersensitivity to the P-lactam antibiotics. The symptoms appearing after the transfusion of the blood unit containing penicillin were identical with those observed after the injection of cephazolin and consistent with an allergic reaction to penicillin.2 These findings indicate that the reaction in our patient was related to the presence of penicillin in the transfused blood unit. Screening of donors at our blood bank includes questioning about the use of drugs. This case shows that this method is not reliable enough and that the presence of penicillins in blood units might induce reactions after transfusion. We suggest that blood units are tested for penicillins, especially when the recipient is known to be allergic to them. Testing is also warranted when conventional methods fail to show any reason for an adverse reaction after transfusion.

Drug-resistant malaria-occurrence, control, and surveillance.

Abstract: Chloroquine resistant strains of Plasmodium falciparum were initially reported during the early 1960s and are currently found in many areas of Asia and South America. The prevalence and degree of resistance are increasing in all affected areas representing a serious setback to antimalaria programs. Alternative drugs are much more expensive and frequently more cumbersome to use. Consequently it is essential that a concerted effort be made to arrest the spread of resistant strains by developing standardized national policies on drug use. The probable genetics and epidemiology of drug resistance are considered in this report and attention is directed to the problems involved in its control. Antimalarial drugs interfere with important physiological functions of the parasites. Chloroquine and mepacrine apparently block acid proteases and peptidases in the phagosomes of intraerythrocytic parasites. Circumstantial evidence from "in vitro" tests suggests that strains of P. falciparum from various parts of the world although primarily susceptible to chloroquine exhibit "a priori" different sensitivities. P. falciparum in the Sobat valley of Ethiopia and in central Sudan appears to be significantly less susceptible to chloroquine than the Uganda I strain. There are no indications yet of chloroquine resistance in P. vivax P. malariae or P. ovale. The relative prevalence of chloroquine resistant infections and the degree of resistance are still on the increase in all affected areas. The development of drug resistance in areas with previously susceptible parasites has thus far always been associated with the use of the particular medicaments. 4 main factors seem to be involved: the degree of drug pressure; the degree of host/parasite contact; the duration of drug pressure; and the type of drug used. The occurrence of chloroquine resistant falciparum malaria requires the urgent attention of the health authorities and that several operational measures be undertaken. Instructions must be provided concerning the principles of drug use in antimalaria programs in the event of the spread of drug resistance and these instructions are reviewed. The methods for the monitoring of drug sensitivity are also reviewed. The World Health Organization (WHO) has developed global monitoring program initially implemented in 1977 in the Southeast Asia Region. Program objectives are identified.

Seroepidemiological studies of malaria in pregnant women and newborns from coastal El Salvador.

Abstract: A cohort of 113 women and their newborns from the coastal area of El Salvador were studied longitudinally to estimate malaria incidence and indirect fluorescent antibody (IFA) response to malaria infection. The district in which the study was conducted had an estimated annual parasite index of 600/1,000 inhabitants, and all malaria infections were treated immediately with a 4-aminoquinoline. In the third trimester of pregnancy, the IFA response to Plasmodium falciparum was significantly depressed. As a result of antimalarial therapy and depressed immune responsiveness, 49% (P. vivax) and 53% (P. falciparum) of the pregnant subjects had a malaria IFA titer less than 1:20 at the time of delivery. Malaria IFA crossed the placenta to the fetus with a step-down of approximately a 4-fold dilution, except for the step-up noted in the P. falciparum titer for 17 of 116 newborns. Due to the overall low prevalence and intensity of maternal IFA, a titer of at least 1:20 was passed to only 23% (P. vivax) and 45% (P. falciparum) of newborns. Passively-acquired malaria IFA degraded with a half-life estimated between 43 and 52 days. During follow-up of infants to 6 months of age, no protection from malaria resulting from passively-acquired antibody could be demonstrated. Because of the limited transplacental immunization of these newborns with antimalarial antibody, it appears that passive immunity can exert little effect on the incidence of infant malaria in coastal El Salvador.

Infectiousness and Gamete Immunization in Malaria

Abstract: Publisher Summary This chapter discusses infectiousness and gamete immunization in malaria. The sources of infectiousness of a malarious individual are the gametocytes of the malaria parasite. These are the sexual stages produced under obscure circumstances during multiplication of the asexual parasites in the bloodstream. On completing their maturation, the gametocytes (male [microgametocytes] and female [macrogametocytes]) undergo no further development in the blood. Immunization with preparations containing gametes of the malaria parasite leads to highly effective suppression of infectiousness to mosquitoes during subsequent blood infection in three laboratory systems: P. gallinaceum in chickens, P. knowlesi in the rhesus monkey, and P. yoelii in the laboratory mouse. Such immunization results in the elaboration of gamete-specific antibodies. When a mosquito ingests gametocyte-carrying blood that contains such antibodies, the gametes are neutralized in the midgut of the mosquito almost immediately following their release during gametogenesis; fertilization is prevented, and the infection in the mosquito is sterilized. The immunity appears to be specific to the sexual stage. Monkeys immunized with preparations of asexual parasites alone do not produce antigamete antibodies, and their sera do not reduce the infectivity of gametocytes to mosquitoes.

Malaria control and long-term periodicity of the disease in Pakistan

Abstract: The classic investigations of the malaria epidemics in the Punjab led to the conclusion that in this most populous and most malarious province of the present-day Pakistan, epidemics occurred regularly at intervals of approximately eight years. Against this background, the results of a Malaria Control Programme launched in 1975 are examined. The Programme, supported by USAID and WHO, represents in economic terms the greatest effort made against malaria in the country. Malathion, the main attack weapon of the Programme, was used on an unprecedented scale. This created logistic and—unexpectedly—toxicity problems among the spraying workers. Despite these difficulties, an over-all reduction of 76% in the slide positivity rate was observed in the first two years of operations of the Programme. The authors warn against measures which may curtail the activities of the Programme when, according to the cyclical periodicity of malaria in the Punjab, an epidemic wave can be expected in 1980–1981, with inevitable repercussions all over the country.

Chemosuppressive field trials in Thailand. IV. The suppression of Plasmodium falciparum and Plasmodium vivax parasitemias by mefloquine (WR 142,490, A 4-quinolinemethanol).

Abstract: The effect of various dosages of mefloquine hydrochloride (WR 142,490) and sulfadoxine-pyrimethamine in the suppression of malaria infections was studied in an area of northeastern Thailand highly endemic for both chloroquine-resistant Plasmodium falciparum and for P. vivax. Both preparations, in all regimens studied, were effective in greatly reducing the incidence of falciparum infections. Mefloquine was more active in preventing vivax parasitemia than sulfadoxine-pyrimethamine; however, this combination remains the commercially available regimen of choice where both parasites occur and P. falciparum is resistant to chloroquine.

Specific antibody-dependent cellular cytotoxicity in human malaria.

Abstract: A micromethod for the study of specific antibody-dependent cellular cytotoxicity (ADCC) in human malaria is described, using cultured, asexual Plasmodium falciparum parasites as viable target cells. Lymphocytes from children with acute malaria, uninfected immune adult Gambians and adult Gambians infected with P. falciparum were capable of killing P. falciparum in vitro in the presence of malaria antibody. A parasite growth-promoting factor, produced by lymphocytes in non-immune serum and at a lymphocyte--parasite ratio of 10:1, in immune serum, was found to produce three-fold increases in growth of P. falciparum. The mechanisms by which ADCC may occur are also discussed.

Anti-lymphocytotoxic antibodies in sera of Thai adults infected with Plasmodium falciparum or Plasmodium vivax.

Abstract: Because of the potential for the elimination of lymphocytes through anti-lymphocytotoxic antibodies we examined individual sera of patients infected with falciparum or vivax malaria for the presence of antibodies against normal peripheral blood mononuclear cells. In assays done at 15 degrees C, 95% of the P. falciparum patients and 98% of the P. vivax patients showed evidence for antibody activity. Activity at 37 degrees C was significantly less than that at 15 degrees C. These studies suggest that infection with malaria induces anti-lymphocytotoxic antibodies which are predominantly cold-reactive. It is possible that this phenomenon plays a role in modulating the immune response of patients toward malaria.

THE EPIDEMIOLOGY OF AVIAN MALARIA IN BLACK-FOOTED PENGUINS (Spheniscus demersus)

Abstract: An understanding of the epidemiology of avian malaria in penguins is essential to the proper management of these birds in captivity Both species of malaria known to affect penguins, Plasmodium relictum and Plasmodium elongatum, are capable of causing an acute and often fatal disease in penguins3'4'6'8'10'14'15'16'17 Considerable work has been devoted to the study of avian malaria, and pathological descriptions for malaria in penguins exist in the literature3'4'6'15 Preventative measures, therapy, and diagnostic techniques have also been studied6'16'17 In-depth studies of the epidemiology of malaria in penguins have not been done to confirm the many assumptions forming the basis for captive penguin management programs around the world This paper summarizes a study of the epidemiology of malaria in African Black footed Penguins at the Baltimore Zoo Individual penguin susceptibility, disease reservoirs, mosquito vectors, host-vector contact, and transmission are examined

Serological investigations in retrospective diagnosis of malaria.

Abstract: Sera were obtained in 415 known cases of malaria (88 residents, 327 immigrants) at different times after diagnosis. Three antigens were used in the indirect fluorscence antibody test to detect antibodies to either Plasmodium falciparum or P vivax. Results in residents and immigrants were analysed separately. Most residents had detectable antibodies within one week after an attack, which began to wane after a month. The strongest reactions were obtained in cases of falciparum malaria with the homologous antigen and in cases of vivax malaria with P fieldi. The overall pattern of results was the same in the immigrants but the proportions positive for malaria antibodies, mean titres, persistence of antibodies, and the cross-reaction were usually greater. Testing for malaria antibodies is probably of value in the retrospective differential diagnosis of malaria in patients who have not been exposed to malaria before but must be interpreted with caution in others.

A longitudinal study of Plasmodium falciparum malaria in the West African savanna using the ELISA technique.

Abstract: Malarial antibody levels were measured by the enzyme-linked immunosorbent assay (ELISA) in two West African populations, one exposed to intense malaria transmission and the other protected The results reflected the transmission of maternal antibody and, in the unprotected population, the subsequent increase of the ELISA values with age reflected the development of the immune response to malaria Malaria control activities reduced ELISA values in the protected population The limitations of the ELISA test used in this study are shown by the fact that numerous infants with previous proven parasitaemia were ELISA-negative Purified antigens are needed to improve the ELISA test for use in serological surveys of malaria

Congenital Malaria Due to Plasmodium falciparum

Abstract: Malaria manifested during the first few months of life may be the result of acquisition during pregnancy, at the time of delivery, or by mosquito bite after birth. Both congenital and perinatal malaria are acquired by the transmission of parasitized maternal erythrocytes across the placenta. An infant is described whose mother was diagnosed to have malaria at six months of gestation. The infant developed intermittent fever at 5 weeks of age and presented with anemia and hepatosplenomegaly at 3 months of age at which time Plasmodium falciparum parasites were found on examination of thick smears of the infant9s blood. IgG and IgM antimalarial antibodies were detected in maternal blood, but only IgG antibodies were found in the infant9s blood at delivery and at the time of diagnosis. These transplacentally transmitted antibodies may afford transient protection for the infant and thus delay the onset of clinical manifestations. Due to the absence of an exoerythrocytic life cycle in congenitally acquired malaria, chloroquine is the drug of choice for treatment. Infections with chloroquine-resistant strains require multiple drug therapy.

Relationship between ABO blood groups and malaria.

Abstract: A total of 736 patients with fever was tested for malaria and classified according to ABO blood group. Of these, 476 cases had patent parasitaemia at the time of investigation. The distribution of blood groups in this group was significantly different from that in 1300 controls from the same area. While group A was found to be more common in malaria cases than in normals, the reverse situation was found for group O. Possible explanations for this are discussed.

The genetics of drug resistance in malaria parasites.

Abstract: The available experimental data on the genetics of drug resistance in malaria parasites are reviewed. Seven possible mechanisms for the origin of drug resistance are considered, and it is pointed out that spontaneous gene mutation is probably the most important. Experiments on the production of pyrimethamine-resistant and chloroquine-resistant strains of rodent Plasmodium species, and on the inheritance of such drug resistance, are reviewed. Relevant biochemical data are also considered in relation to the genetics of drug resistance. Studies on competition between drug-sensitive and drug-resistant parasites in mixed populations of rodent plasmodia are described. The implications of these findings for drug resistance in P. falciparum are discussed.

Malaria and growth stunting in young children of the highlands of Papua New Guinea.

Abstract: In a Highlands Valley, at low altitude, malaria is a contributing factor to stunting of growth, an expression of chronic malnutrition, in young children. The affect is most marked in children under two years of age, and may result from retarded intrauterine growth, although malaria also possibly exerts a direct affect on growth in young children. In the absence of a malaria control programme, distribution of amodiaquine to young children and chloroquine to pregnant women and mothers of young children, could reduce not only unnecessary mortality and ill health, but also contribute to the nutritional well being of growing children. In accessible areas the regular MCH clinics held every month could effect such a prophylaxis programme among these at risk groups.