Showing papers on "Malaria published in 1985"
TL;DR: A standardized method of examination in epidemiological surveys is proposed: this includes the systematic rapid determination of parasite density, which could help in the detection of malaria parasites in semi-immune populations.
Abstract: The results of epidemiological surveys and the follow-up of malaria endemicity are often difficult to compare due to the high frequency of low-density parasitaemia in semi-immune populations. Detecting malaria parasites is dependent on the conditions and methods of parasitological examination. A standardized method of examination in epidemiological surveys is proposed: this includes the systematic rapid determination of parasite density.
223 citations
TL;DR: Recombinant proteins composed of 16, 32, or 48 tandem copies of a tetrapeptide repeating sequence found in the CS protein were efficiently expressed in the bacterium Escherichia coli and resulted in the production of high titers of antibodies that reacted with the authentic CS protein on live sporozoites and blocked sporozoite invasion of human hepatoma cells in vitro.
Abstract: The circumsporozoite (CS) protein of the human malaria parasite Plasmodium falciparum may be the most promising target for the development of a malaria vaccine. In this study, proteins composed of 16, 32, or 48 tandem copies of a tetrapeptide repeating sequence found in the CS protein were efficiently expressed in the bacterium Escherichia coli. When injected into mice, these recombinant products resulted in the production of high titers of antibodies that reacted with the authentic CS protein on live sporozoites and blocked sporozoite invasion of human hepatoma cells in vitro. These CS protein derivatives are therefore candidates for a human malaria vaccine.
220 citations
185 citations
TL;DR: Tests with control sera obtained from HTLV-III seropositive homosexual men and American subjects repeatedly infected with malaria who had high antibody titres against P falciparum indicated that there was no cross-reactivity between P falCIParum and these retroviruses.
157 citations
TL;DR: The analysis of the clinical data and the parasitological results clearly demonstrates the importance of the parasite density determination for the diagnosis of clinical malaria.
Abstract: In highly malaria-endemic areas, thick smears are usually positive regardless of the clinical context. Therefore the simple positivity or negativity of the thick smear is not an adequate criterion for distinguishing malaria from other causes of fever. In order to define simple parasitological and clinical criteria for diagnosing clinical malaria with a small risk of error, a study was undertaken in a rural area in the Congo where malaria transmission is intense and perennial. Results of the systematic determination of the parasite density of 1562 samples from persons of all ages considered representative of the population of the studied area are compared to those from 327 febrile patients, 204 patients detected during medical consultations held in the villages and 123 febrile schoolchildren detected during surveys for fever. The analysis of the clinical data and the parasitological results clearly demonstrates the importance of the parasite density determination for the diagnosis of clinical malaria. Clinical Plasmodium falciparum malaria is unlikely to occur in children under 15 years if the parasite/leucocyte ratio is less than 1·5. On the contrary this diagnosis is very probable if the parasite/leucocyte ratio is higher than 2. Clinical criteria were too non-specific to serve as useful diagnostic criteria.
148 citations
TL;DR: Women using chloroquine during pregnancy for chemosuppression of malaria can be reassured that it is not a strong teratogen, but if it is to be used the risk of developing malaria should be balanced against the lack of data to determine whether it carries a low teratogenic risk.
Abstract: A cohort of 169 births to women who were exposed throughout pregnancy to chloroquine 300 mg base once a week for chemosuppression of malaria was studied. The birth defects in this cohort were compared with those in a control group of 454 births to women who were not exposed to chloroquine, most of whom lived in non-malarious areas. The proportion of birth defects in the exposed group was not significantly different from that in the control group. This observation must be considered within the limitations of the study, which could detect only a strong teratogenic effect. It could not exclude risks lower than a 5.7-fold increase in the incidence of birth defects when chloroquine was used. Women using chloroquine during pregnancy for chemosuppression of malaria can be reassured that it is not a strong teratogen, but if it is to be used the risk of developing malaria should be balanced against the lack of data to determine whether it carries a low teratogenic risk.
124 citations
TL;DR: Plasma protein binding of quinine was measured in 12 patients with cerebral malaria on the first and seventh day of treatment, and in 7 patients with uncomplicated falciparum malaria on admission and also one month later, and the ratio of cerebrospinal fluid to free (unbound) plasma quInine was 0.55 +/- 0.33 which suggests that qu inine does not freely cross the blood brain barrier.
Abstract: Plasma protein binding of quinine was measured in 12 patients with cerebral malaria on the first and seventh day of treatment, and in 7 patients with uncomplicated falciparum malaria on admission and also one month later. Binding was significantly higher and therefore the proportion of free drug was lower in cerebral malaria patients (free: total quinine concentration; 7.2 +/- 3.5%, mean +/- SD, on admission; 7.4 +/- 5.3% on day 7) compared with uncomplicated malaria patients on admission (10.2 +/- 5.8%) or following recovery (11.0 +/- 5.5%, n = 6) P = 0.011. Binding was significantly correlated with the red cell/total concentration ratio r = 0.56, P less than 0.0001. The ratio of cerebrospinal fluid to free (unbound) plasma quinine was 0.55 +/- 0.33 which suggests that quinine does not freely cross the blood brain barrier. These findings are relevant to the interpretation of total plasma or serum concentration, and may explain the rarity of serious quinine toxicity in severe falciparum malaria.
98 citations
TL;DR: Children protected against malaria had a higher mean haemoglobin level and a higher packed cell volume than control children, and they showed fewer abnormalities of their red cells, and Serum ferritin is probably an unreliable index of iron status in children with malaria.
Abstract: One hundred and ninety-eight Nigerian children who received weekly chemoprophylaxis with chloroquine from shortly after birth until the age of one year or two years and 185 age-matched controls were studied Chemoprophylaxis with chloroquine was partially, but not completely, effective in controlling malaria Clinical malaria was documented significantly less frequently in protected children than in control children, and only 9% of random blood films obtained from protected children were positive for Plasmodium falciparum while 41% of random blood films from control children were positive for this parasite Mean malaria antibody levels were lower in protected than in control children; for ELISA and precipitin antibodies the difference between the two groups was less marked at two years than at one year Mortality was similar among protected and among control children No rebound mortality or morbidity was observed after chemoprophylaxis was stopped
86 citations
TL;DR: It is vital that all measures possible should be taken to protect such new compounds, their deployment in the form of judiciously selected combinations with other antimalarials being an essential procedure that should be followed.
Abstract: The resistance in human malaria is mainly of practical importance in relation to Plasmodium falciparum. Strains resistant not only to chloroquine but also to dihydrofolate reductase inhibitors, and even to potentiating combinations of these with sulphonamides or sulphones, are appearing in an ever increasing geographical area which now includes tropical Africa and India. Few new drugs are available or foreseen for the near future, mefloquine and artemisinine being the leading contenders. It is vital that all measures possible should be taken to protect such new compounds, their deployment in the form of judiciously selected combinations with other antimalarials being an essential procedure that should be followed. Drugs in new chemical classes and with different modes of action are still urgently needed. Reliance should not be placed on drugs alone to control malaria on a community basis.
83 citations
TL;DR: In this paper, the authors reported that the geometric mean red cell folate level of children exposed to malaria was significantly higher than the mean level of control children; and it may be that malaria raises the red cell folic acid through intracellular synthesis by malaria parasites.
Abstract: Haematological measurements were made in 198 Nigerian children aged three months to two years who received weekly malaria chemoprophylaxis with chloroquine from shortly after birth until the age of one or two years and in 185 age-matched control children. Children protected against malaria had a higher mean haemoglobin level and a higher packed cell volume than control children, and they showed fewer abnormalities of their red cells. Total and differential white blood cell counts, mean plasma folate and mean serum ferritin concentrations were similar in both groups of children. However, the geometric mean red cell folate level of children exposed to malaria was significantly higher than the mean level of control children; and it may be that malaria raises the red cell folate through intracellular synthesis by malaria parasites. Children with malaria parasitaemia had a significantly lower haemoglobin and packed cell volume and a significantly higher geometric mean red cell folate and ferritin level than children without parasitaemia. Serum ferritin is probably an unreliable index of iron status in children with malaria.
80 citations
TL;DR: Mefloquine was well tolerated by patients with glucose-6-phosphate dehydrogenase deficiency or heterozygous haemoglobin E, and was equally effective in the treatment of falciparum malaria.
Journal Article•
TL;DR: The following three-phase model for the oncogenesis of Burkitt's lymphoma could account for virtually all the currently known facts and be tested by further laboratory and field studies.
Abstract: Nearly all epidemiological characteristics of Burkitt's lymphoma (BL) can be explained on the basis of relationships of BL to the intensity of the host response to Plasmodium falciparum. The major epidemiological associations are: the high degree of geographic correlation between the incidence rate of BL and the intensity of P. falciparum transmission, both at a global level and within individual countries; the close correlation between the age incidence of BL and the age of acquiring maximum levels of antimalarial immunoglobulin; the relative protection from BL by residence in urban areas, where levels of malaria transmission are lower, compared with rural areas; the decline in BL incidence in areas where death rates due to malaria have declined and, within such areas, a differential decline in BL incidence in people making better use of health facilities; the older age of onset in patients who have migrated from low-intensity to high-intensity malaria areas as compared with patients born in the high-intensity areas - the higher absolute age-specific incidence rate in those above age ten in this immigrant group being consistent with the hypothesis that intense malaria infection and consequent host defence response serve as the major triggering event in the pathogenesis of the lymphoma; the inverse geographic correlation between the average age of onset of BL and the intensity of falciparum malaria infection. An inverse association of BL with sickle-cell trait (AS haemoglobin) would provide strong evidence for the role of intense falciparum malaria, but most studies to date have not achieved statistical significance. Time-space clustering and reports of seasonal variation in BL incidence would indicate that a precipitating factor operates over a relatively short time-span, at least in some areas. Combining the evidence concerning cytogenetics, Epstein-Barr virus (EBV) and falciparum malaria, the following three-phase model for the oncogenesis of BL could account for virtually all the currently known facts and be tested by further laboratory and field studies: Primary infection with EBV, perhaps early and intense, leads to the immortalization of large numbers of B lymphocytes. Severe falciparum malaria then leads to an intense host response with particular proliferation of the EBV-infected B lymphocytes. Finally, the great increase in the B lymphocytes provides a much higher statistical opportunity for the emergence of the cytogenetically abnormal BL cell.
Journal Article•
TL;DR: A proposal is outlined for a rational strategy for malaria control in the Gezira-Managil Irrigated Scheme and the mosquito vector developed resistance to several insecticides.
Abstract: The development of malaria control in the Gezira-Managil Irrigated Scheme of Central Sudan has gone through several phases. As a result of agricultural and irrigation practices in the Gezira, falciparum malaria transmission became perennial instead of seasonal and the mosquito vector developed resistance to several insecticides. Subsequent failure to maintain control led to serious epidemics after 1971. By 1975 malaria was again put under control through an annual round of house spraying with malathion from 1975 to 1980, and with fenitrothion since 1981. A proposal is outlined for a rational strategy for malaria control in the future.
TL;DR: Monitoring of serum-interferon levels among 189 patients followed after and sometimes during an acute episode of malaria due mainly to Plasmodium falciparum found the onset of circulating immune interferon was found to be preceded or accompanied by that of IFN-alpha.
Abstract: The present study concerns the monitoring of serum-interferon (serum-IFN) levels among 189 patients followed after and sometimes during an acute episode of malaria due mainly to Plasmodium falciparum (P. falciparum). Of these patients, 110 known to have no other parasitic or infectious disease were followed in France; 79 were from Thailand, among which 25 cases of neuromalaria were diagnosed. In a first four-month survey conducted in France, among 100 patients seen after the acute attack, serum-IFN-gamma was characterized among 87% cases for which at least two sera were controlled, whereas in a healthy population no serum-IFN was present. When efforts were concentrated on screening ten cases during the first 48 h of the febrile attack, serum-IFN-alpha was mainly characterized, whereas serum-IFN-gamma was present only once. Elevated leukocyte 2',5' oligoadenylate synthetase levels were found among several IFN-alpha positive patients of this study group. A peculiarity pertaining to the patients from Thailand was that one-third (25 cases) were cerebral malaria cases. Among these, 15 were followed under hospitalization during the first 96 h. In this study group, the onset of circulating immune interferon was found to be preceded or accompanied by that of IFN-alpha. Thus, if serum-IFN-gamma is largely characterized among malaria patients followed after the acute attack, it is possible that the onset of circulating immune interferon is generally preceded by that of IFN-alpha.
TL;DR: The epidemiology of malaria was studied in a West African mining town (Yekepa) and three surrounding zones defined as Close, Middle and Far areas and malariometric parameters were investigated in children two to nine years of age at the end of the rainy season.
Abstract: The epidemiology of malaria was studied in a West African mining town (Yekepa) and three surrounding zones defined as Close, Middle and Far areas.Malariometric parameters were investigated in child...
Journal Article•
TL;DR: Serial in vitro and in vivo tests for chloroquine sensitivity of Plasmodium falciparum were carried out from 1979 to 1982 in an area of E. Africa where chemosuppression withchloroquine had been attempted since 1977, and resistance to pyrimethamine was found.
Abstract: Serial in vitro and in vivo tests for chloroquine sensitivity of Plasmodium falciparum were carried out from 1979 to 1982 in an area of E. Africa where chemosuppression with chloroquine had been attempted since 1977. Within 1½ years there were signs of a decreasing drug response. Chloroquine resistance was first detected in 1981 and this increased markedly in 1982. Other contributory causes for the rise of parasite rates in children were possibly a decline in the efficiency of the drug distribution system and also immunological factors. Evidence of resistance to pyrimethamine was also found. Observations were made of the heterogeneity of the parasites' responses with emerging resistance. Implications for the future are discussed.
TL;DR: The indigenous perspectives on malaria and the biomedically predictive powers of various biocultural symptoms are discussed and evaluated as an integrative and valuable means of assessing the impact of malaria in an endemic region.
Book•
01 Jan 1985
TL;DR: This book contains 70 selections of studies on the structure of the Gene Encoding of Immunodominant Surface Antigen on the Sprozoite of the Human Malaria Parasite Plasmodium falciparum, and Viral Genes, Cytotoxic T Lymphocytes and Immunity.
Abstract: This book contains 70 selections. Some of the selection titles are: Structure of the Gene Encoding of Immunodominant Surface Antigen on the Sprozoite of the Human Malaria Parasite Plasmodium falciparum; Cloning and Expression in Bacteria of the Genes for Merozite-specific Antigens from the Malaria Parasite Plasmodium falciparum; A Major Surface Antigen of Plasmodium falciparum in Merozoites: Studies on the Protein and its Gene; Genetic Construction of Cholera Vaccine Prototypes; and Viral Genes, Cytotoxic T Lymphocytes and Immunity.
TL;DR: An IgG2a isotype monoclonal antibody from a hybridoma cell line, PYG-1, has been used to identify the target antigens on the gametes and to affinity-purify sufficient quantities of specific gamete antigen to facilitate vaccination studies.
Abstract: Malaria vaccination with preparations of microgametes has been shown to inhibit transmission of Plasmodium spp. to the mosquito vectors of avian, rodent and simian parasites. This transmission-blocking immunity results from the induction of microgamete-agglutinating antibodies in the vaccinated host which, when ingested in a mosquito blood meal, react with exflagellating microgametes in the midgut to prevent fertilization and oocyst development. Here we have passively transferred the immunity with gamete-specific monoclonal antibodies raised against the rodent malaria parasite Plasmodium yoelii nigeriensis, and an IgG2a isotype monoclonal antibody from a hybridoma cell line, PYG-1, has been used to identify the target antigens on the gametes and to affinity-purify sufficient quantities of specific gamete antigen to facilitate vaccination studies. This transmission-blocking monoclonal antibody immunoprecipitated microgamete antigens of apparent relative molecular mass (Mr), 67K (67,000), 59K, 57K, 42K and 35K. Immunization of mice with these proteins before infection and mosquito feeding led to a 85-99.7% reduction in transmission to the mosquito vector; vaccination via intravenous or intramuscular routes was equally effective and did not require an adjuvant.
TL;DR: The immune response of 198 young Nigerian children protected against malaria by chemoprophylaxis with chloroquine to immunization with triple, poliomyelitis, measles, typhoid, meningococcal and BCG vaccines was compared with the immune response to vaccination of 185 control children as discussed by the authors.
Abstract: The immune response of 198 young Nigerian children protected against malaria by chemoprophylaxis with chloroquine to immunization with triple, poliomyelitis, measles, typhoid, meningococcal and BCG vaccines was compared with the immune response to vaccination of 185 control children. Good responses to triple, measles and BCG vaccines were shown by children in both groups; poorer responses were obtained to poliomyelitis, typhoid and meningococcal vaccines. The response to immunization of protected children was similar to that observed among control children for all the vaccines tested except for meningococcal polysaccharide vaccine. Protected children showed a significantly greater antibody response to both group A and group C meningococcal polysaccharides than control children. This finding supports the results of previous studies which have shown that the immune response to meningococcal polysaccharide vaccines is adversely affected both by acute malaria and by asymptomatic malaria parasitaemia.
TL;DR: This study shows that it is possible to suppress ahaptoglobinaemia within a few weeks by antimalarial chemoprophylaxis, and that some individuals are more susceptible in relation to Hp2 gene.
Abstract: The lack of serum haptoglobin in Africans has been investigated in the Congo, Central Africa, where HpO prevalence is about 30%. This study shows that it is possible to suppress ahaptoglobinaemia within a few weeks by antimalarial chemoprophylaxis, that it does not occur in protected individuals, that ahaptoglobinaemia reappears at its original incidence levels after interruption of chemoprophylaxis, and that some individuals are more susceptible in relation to Hp2 gene. Malaria is the only significant cause of ahaptoglobinaemia in subjects both with and without detectable parasitaemia. The possible mechanisms involved are discussed.
Journal Article•
TL;DR: The results suggest that endotoxin (LALT positivity) of the plasma of malaria patients is derived from either the parasites themselves or from the gut, and relates to parasitaemia, leucocytosis and elevated serum enzymes, but not to the clinical syndrome of cerebral malaria.
Abstract: Limulus amoebocyte lysate test (LALT) was used to detect endotoxin-like substances in the plasma of 15 patients with cerebral malaria, 28 patients with uncomplicated falciparum malaria and 30 healthy controls. On admission, 67% of cerebral malaria patients were positive, whereas only 21.4% of uncomplicated malaria patients and none of controls were positive. Among uncomplicated malaria cases, four of eight patients with parasitaemia over 90,000/mm3 were LALT positive whereas only two of 20 patients with parasitaemia of less than 90,000/mm3 were positive. A follow-up study in cerebral malaria patients showed some variation in LALT positivity rate from day to day (85.7% on day 1, 53.3% on day 3 and all negative on discharge from hospital). LALT positivity bore no relationship to gram negative bacteraemia. Leucocytosis and elevated serum enzymes were more frequently found in LALT-positive patients. Our results suggest that endotoxin (LALT positivity) of the plasma of malaria patients is derived from either the parasites themselves or from the gut. It relates to parasitaemia, leucocytosis and elevated serum enzymes, but not to the clinical syndrome of cerebral malaria.
03 Aug 1985
TL;DR: A global review of the problem of malaria accidentally transmitted by blood transfusion revealed that about 350 cases were reported during the period 1911-50 and 1756 during 1950-72 as mentioned in this paper.
Abstract: A global review of the problem of malaria accidentally transmitted by blood transfusion revealed that about 350 cases were reported during the period 1911-50 and 1756 during the period 1950-72. The great rise in the frequency of blood transfusions in medical practice and the increase of travel between countries in which malaria is absent and those where it is prevalent render transfusion malaria a problem of clinical and public health importance. Attention is drawn to the value of modern serological methods for the screening of blood donors.
TL;DR: Marcel Hommel discusses the presence of variant antigens and endothelial-binding molecules on the surface of infected erythrocytes in the context of malaria immunity.
Journal Article•
TL;DR: The reactivation of the varicella-zoster virus in these patients may reflect transient depression of cell-mediated immunity by these malaria parasites, possibly augmented by the chloroquine used in their treatment.
Abstract: Herpes zoster is uncommon in normal children in the 0-9 year age group. However, its incidence is markedly increased in those who are immunosuppressed. Six Papua New Guinean children under 9 years of age developed herpes zoster following an episode of malaria, due to Plasmodium falciparum or Plasmodium vivax which was treated with chloroquine. The reactivation of the varicella-zoster virus in these patients may reflect transient depression of cell-mediated immunity by these malaria parasites, possibly augmented by the chloroquine used in their treatment.
TL;DR: Asexual blood stage vaccines, therefore, are not likely to achieve the interruption of malaria transmission if used alone, no matter how effectively they limit mahuial morbidity and mortality.