Showing papers on "Malaria published in 1975"

Erythrocyte receptors for (Plasmodium knowlesi) malaria: Duffy blood group determinants

Abstract: Duffy blood group negative human erythrocytes (FyFy) are resistant to infection by Plasmodium knowlesi, a simian malaria that infects Duffy positive human erythrocytes. The P. knowlesi resistance factor, Duffy negative erythrocytes, occurs in high frequency in West Africa, where the people are resistant to vivax malaria. This suggests that Duffy blood group determinants (Fya or Fyb) may be erythrocyte receptors for P. vivax.

Mefloquine (WR 142,490) in the treatment of human malaria

Abstract: Mefloquine hydrochloride, a new 4-quinolinemethanol, was administered as a single oral dose to 47 volunteers infected with malaria. Treatment resulted in rapid clearence of fever and parasitemia. No recrudescence of parasites was observed after treatment of chloroquine-sensitive infections of Plasmodium falciparum. More significantly, in nonimmune persons with chloroquine-resistant infections, 1 gram of mefloquine cured 10 of 12 patients and 1.5 grams cured all 8 patients who received this dose of the drug. The marked activity of a single dose of mefloquine against chloroquine-resistant strains of Plasmodium falciparum suggests that this agent may be more useful than currently available drugs are for the treatment of drug-resistant malaria.

Evidence for a malaria mitogen in human malaria.

Abstract: HYPERGAMMAGLOBULINAEMIA is a prominent feature of human malaria. Serum levels of IgM and IgG rise rapidly in acute infections1, and malaria has been implicated as an important cause of the raised levels of these immunoglobulins and the increased prevalence of rheumatoid factor and other autoantibodies found in healthy subjects in many parts of the tropics. Only a small proportion of the immunoglobulin produced in malaria can be shown to be specific antibody2. The mechanisms underlying the production of large amounts of nonspecific immunoglobulin in malaria have not been established. Excessive immunoglobulin production could result from a breakdown in normal control mechanisms, perhaps as a consequence of the deletion of suppressor T cells. Alternatively, it could be due to the production during malarial infection of a substance capable of stimulating lymphocytes nonspecifically3. Here we present evidence for the production of a mitogen in children with acute Plasmodium falciparum malaria.

Studies on the infectivity of tropical African strains of Plasmodium falciparum to some southern European vectors of malaria.

Abstract: Preliminary experiments in Garki, Nigeria, with A. atroparvus from Italy have shown a refractoriness to infection with the local strain of P. falciparum. Comparative studies involving A. labranchiae and two strains of A. atroparvus, all from Italy, and one local strain of A. gambiae species B, were carried out at Kismu, Kenya. While oocysts developed in 77% of A. gambiae and, from day 14 onwards, 100% of the oocyst positive mosquitos had sporozoites in the salivary glands, oocysts were seen in only 4% of one of the A. atroparvus strains; the development of these oocysts appeared to be arrested at an early stage. A labranchiae and the other strain of A. atroparvus showed no oocysts. None of the Italian mosquito strains was positive for sporozoites. It is concluded that the importation of falciparum malaria cases from tropical Africa is unlikely to produce epidemics in those southern European areas where A. labranchiae and A. atroparvus used to be malaria vectors.

New serological test for malaria antibodies.

Abstract: In an enzyme-linked immunosorbent assay test for malaria antibodies, antibodies to Plasmodium vivax and P. falciparum in man are detected using a crude antigen prepared from the simian malaria parasite P. knowlesi. The test may be suitable for epidemiological studies.

Enteric fever in young Yoruba children.

Abstract: Ninety-seven Nigerian children under 5 years of age had typhoid or paratyphoid fever proved by blood culture. The presented with fever, anaemia, gastrointestinal or neurological disturbances, and typhoid and paratyphoid appeared clinically indistinguishible. In this holoendemic malarial area, malaria was the most important differential diagnosis, and may have contributed to the concomitant anaemia seen in the majority of patients. Despite vigorous therapy with chloramphenicol or trimethoxazole, and blood transfusion where indicated, the mortality in both typhoid and paratyphoid was high (18% in both groups).

Receptivity to malaria in Europe

Abstract: Experimental work has confirmed the refractoriness of Anopheles atroparvus to tropical strains of Plasmodium falciparum to which A. labranchiae may also be refractory. This indicates a lower receptivity to malaria in Europe than the existing vector densities and increasing number of parasite carriers would suggest.

Amodiaquine resistant falciparum malaria in Thailand.

Abstract: Amodiaquine cured 38% (13/34) of patients with falciparum malaria in Southeast Thailand. Chloroquine cured 0% (0/13). The cure rates with amodiaquine were the same whether a 1.5 g or 2.0 g course was used. Most patients were resistant to amodiaquine at the RI level and to chloroquine at the RII level. In hospital, amodiaquine cleared parasitemia more frequently than did chloroquine. With the 2.0 g course of amodiaquine, the parasite clearance time was 77 hours; the fever clearance time of 36 hours was low and suggests that amodiaquine does not cause a drug fever. Because of resistance, chloroquine should not be used for falciparum malaria in Thailand. Routine use of amodiaquine is not indicated because more effective drugs are available.

Falciparum malaria cured by quinine followed by sulfadoxine-pyrimethamine.

Abstract: Quinine (at least four doses given at intervals of eight to 12 hours) followed by a single dose of sulfadoxine-pyrimethamine (Fansidar) is the most effective treatment of chloroquine-resistant falciparum malaria This regimen cured 96% of patients (302 out of 314) with an average initial parasite count of 90 X 10-9/1

Malaria, favism and glucose-6-phosphate dehydrogenase deficiency.

Abstract: Although glucose-6-phosphate dehydrogenase deficient individuals may suffer (sometimes fatally) from favism, a high incidence of this trait occurs in many Mediterranean populations This apparent paradox is explained on the basis of a synergistic interaction between favism and G-6-PD deficiency that provides increased protection against malaria compared to that of the G-6-PD deficiency alone This relationship is analogous to that between various hemoglobins and malaria in that there is selection for a more severe trait if it provides more protection against malaria

New Evidence for a Late Introduction of Malaria into the New World [and Comments and Reply]

Abstract: New evidence is offered to strengthen the case for a post-Conquest introduction of malaria into the New World. An investigation of human physiological factors influencing host selection by malaria vectors revealed a strong preference by Anopheles gambiae for human hosts with blood-group O. The unique, overwhelming group-O frequency present among indigenous American populations is seen as a result of mother-child ABO incompatibility effects operating in the absence of the positive selection pressures by malaria vectors favoring enhanced survival for genes A and B that the investigation findings suggest. It is proposed that had malaria been present to act upon the original gene pool, a balanced ABO polymorphism would be found in the New World Indians today.

New Evidence for a Late Introduction of Malaria into the New World

Abstract: IN A SERIES OF EXPERIMENTS designed to investigate the human physiological factors influencing malaria vectors in their choice of host, new evidence has accrued that gives additional weight to the arguments for a post-Conquest introduction of malaria into the New World. The procedures, results, and implications of the investigations follow a brief introductory account of the dispute. Malaria has figured prominently in much of human history and today continues as the single greatest destroyer of human populations. The World Health Organization estimated in 1952 that more than 250,000,000 persons, 6.3% of the world's population, were subject to the threat of malaria. Despite more than half a century of organized

Vector control of filariasis in the Solomon Islands.

Abstract: In Solomon Islands, filariasis is caused by the nocturnally perodic form of Wuchereria bancrofti and is transmitted by the same vectors of malaria. This study explores the control of this disease as an additional effect of the Malaria Eradication Programme.

Anaemia in mice with concomitant Schistosoma mansoni and Plasmodium berghei yoelii infection.

Abstract: 1 1 The effect on anaemia in mice given Plasmodium berghei yoelii 3 and 5 weeks after exposure to Schistosoma mansoni cercariae, was investigated 2 2 Haematological criteria (PCV and haemoglobin levels), reticulocytosis, parasitaemia and splenomegaly were used as indices 3 3 Anaemia was severe in the animals given P b yoelii and in those with mixed infection ( P b yoelii + S mansoni ) Malaria was found to dominate the picture until the clearance of the parasitaemia The effect of the interaction between the diseases on the anaemia was nil 4 4 Toward the end of the experiment, moderate splenomegaly was observed in the mice with mixed infection

Enhanced Trypanosoma musculi infections in mice with concomitant malaria.

Abstract: A PHASE of immunodepression is characteristic of experimental malaria infections and, in mice, immune responses to antigens as diverse as sheep red blood cells1, tetanus toxoid2, oncogenic viruses3 and Toxoplasma gondii4 are diminished. From immunological and epidemiological viewpoints it is important to know what happens when animals are infected with another agent during this period of immunodepression. The agent must be carefully chosen; it must be able and likely to coexist with the malaria parasite in vivo, be easy to monitor and elicit a well defined immune response. Trypanosoma musculi, an avirulent murine trypanosome, fulfils these criteria. There is no cross immunity between it and rodent malarias5, the immune response has been very carefully characterised6–8 and the progress of the infection can be monitored easily by taking minute quantities of blood. We have found that T. musculi infections are considerably enhanced in mice coincidentally infected with an avirulent malaria parasite, Plasmodium yoelii (P. berghei yoelii)9.

The seroepidemiology of malaria in Middle America. II. Studies on the Pacific coast of Costa Rica.

Abstract: Serologic studies for malaria using the indirect fluorescent antibody technique suggest that active transmission is either absent or very low in 6 villages on the Pacific side of Costa Rica. Positive titers (1:20 or higher) were seen in the under-15-year age group in three of the study localities, but only 5 such responses were encountered among 249 people examined in this age range. In the adults (15 years and over) from the same 3 villages there were 68 positive titers among 161 examined. There were 43 positive responses in 189 adults from the remaining 3 villages where none of 307 persons under 15 years of age showed a titer of 1:20 or higher to any of the 3 malaria antigens tested (Plasmodium falciparum, P. vivax and P. malariae). These data suggest that the positive responses in the latter villages are more likely to be associated with old or imported cases than with current local transmission. Serologic responses of 1:80 or higher to the P. falciparum antigen suggested the continued presence of this parasite in the population in spite of the paucity of positive blood smears with this species in recent years. Positive titers with the P. malariae antigen suggest that this parasite is probably still present in the area. Such serologic studies help to indicate areas where malaria transmission is active and provide information on parasite reservoirs in particular populations.

Comparison of diaminodiphenylsulphonepyrimethamine and sulfadoxine-pyrimethamine combinations in the treatment of falciparum malaria in Thailand.

Abstract: The dapsone-pyrimethamine combination in the doses employed in this study was not sufficiently efficacious for use in the treatment of falciparum malaria. In contrast, the efficacy of the standard sulfadoxine-pyrimethamine regimen in the treatment of falciparum malaria was confirmed.

Natural infections of Anopheles albimanus with Plasmodium in a small malaria focus.

Abstract: Entomologic surveys conducted in a small village in an area of known high malaria transmission in El Salvador yielded a high rate of infection in Anopheles albimanus collected inside houses in which cases of malaria had occurred. Of 324 specimens dissected, 12 were found to harbor sporozoites or oocysts. This is in contrast to prior reports of extremely low infection rates in collections of this species from malarious areas, and suggests that under some circumstances A. albimanus does meet the criteria of an effective malaria vector.

Observations on malaria in Indonesian timor.

Abstract: Malaria parasitemias were found in 35% of 520 individuals from a village in Timor, Indonesia. Plasmodium falciparum accounted for 80% of infections. The existence of P. ovale in Timor is reported for the first time. The WHO Standard Field Test for drug resistance did not reveal significant resistance of P. falciparum or P. vivax to chloroquine.

The seroepidemiology of malaria in Middle America. I. Longitudinal studies on populations in a low incidence area of El Salvador.

Abstract: Serologic profiles were established using the indirect fluorescent antibody test in a longitudinal study of six villages in an interior area of El Salvador. Positive serologic responses as well as active cases found through the voluntary collaborator posts occurred primarily in adult males, suggesting that much of the malaria experience in the study area resulted from exposure of this segment of the population in more malarious areas where they traveled to engage in temporary agricultural labor. Malaria incidence was generally low but transmission potential apparently varied markedly even over relatively small distances. Serologic profiles reflected the malaria experience in the population sampled, but many localities were widely dispersed and samples taken from village centers were found in some cases not to be representative of the entire locality population in terms of malaria exposure. The indirect fluorescent antibody technique was found to reflect the malaria experience in the population segments examined. When these data were correlated with the surveillance data from the voluntary collaborator posts, the epidemiology of malaria in the study area was more thoroughly understood.