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Within two months of treatment for falciparum malaria, Plasmodium vivaxinfections developed in 58 (33%) of 174 patients who had received a quinine or quinidine regimen and in 46 (32%) of 145 patients who had received mefloquine with inpatient follow-up of more than six weeks. The time to vivax relapse was significantly longer after mefloquine treatment (median 47 days, range 30-65) than after quinine or quinidine treatment (21 days, 15-36; p<0·0001). All patients remained outside areas of malaria transmission. These findings suggest a very high rate of double infection in Thailand with acute suppression of vivax by falciparum malaria, and warrant evaluation of radical therapy with primaquine in certain patients with acute falciparum malaria.
Vulture populations are experiencing rapid declines across the globe. While the declines have been most precipitous in Asia, recent reports suggest African populations are likewise imminently threatened. As the factors underlying these general population trends are multifaceted and will vary in their relative intensity spatially, it is imperative that monitoring data across different vulture populations is assimilated if targeted conservation action is to prove most effective. In this study, we highlight a medium-term decline in the African White-backed Vulture Gyps africanus population inhabiting the southern Kalahari, South Africa, using a long-term behavioural data set collected from a habituated population of meerkats Suricata suricatta. Meerkats emit an alarm call on sighting airborne vultures, which elicits a group-level response, such that the rates at which this behaviour is recorded in meerkats provides a high-resolution proxy for local vulture abundance. Although unconventional, this sampling method uncovered a steady decline over 17 years in White-backed Vulture numbers that mirrors the temporal decline recently documented in other southern African populations.
A rapid method for the identification and differentiation of Burkholderia pseudomallei and Burkholderia thailandensis colonies is described. It consists of simultaneous use of 2 monoclonal antibody-based latex agglutination test systems. The anti-lipopolysaccharide test reacts with both species, whereas the anti-exopolysaccharide reacts only with B. pseudomallei. Compared with classical biochemical tests, the method is highly reproducible and accurate. It is particularly useful for the identification of the organisms in environmental specimens, which may contain both of these Burkholderia species.
Membranes obtained from whole-cell lysates of Burkholderia (Pseudomonas) pseudomallei (strain 319a) were separated into four fractions by sucrose density gradient centrifugation. Membranes were characterized by enzymic and chemical analyses, and by SDS-PAGE. Cytoplasmic membranes and two forms of outer membranes (OM-1, OM-2) were detected. The major outer-membrane proteins had M r values of 70000, 38000, 31000, 24000 and 17000. To determine which outer-membrane proteins were common to B. pseudomallei strains, OM-1 fractions from 12 different strains were prepared. SDS-PAGE analysis of these fractions demonstrated that the five major outer-membrane proteins were common to the strains tested. Further studies have shown that an M r 110000 protein, which is oligomeric in that it migrates as an M r 38000 protein upon heating at 95 °C and which is peptidoglycan-associated, serves as a porin in B. pseudomallei. Using proteoliposomes reconstituted from this protein and phospholipid, it was demonstrated by the liposome-swelling assay that this protein acts as a porin through which small saccharides may diffuse. Further characterization of this M r 38000 protein will be important in delineating the role of this molecule in the permeability of the B. pseudomallei outer membrane.
Many important questions in ecology and evolutionary biology can only be answered with data that extend over several decades and answering a substantial proportion of questions requires records of the life histories of recognisable individuals. We identify six advantages that long-term, individual based studies afford in ecology and evolution: (i) analysis of age structure; (ii) linkage between life history stages; (iii) quantification of social structure; (iv) derivation of lifetime fitness measures; (v) replication of estimates of selection; (vi) linkage between generations, and we review their impact on studies in six key areas of evolution and ecology. Our review emphasises the unusual opportunities and productivity of long-term, individual-based studies and documents the important role that they play in research on ecology and evolutionary biology as well as the difficulties they face.
No abstract is provided for this article.
Plasmodium vivax is a major cause of febrile illness in endemic areas of Asia, Central and South America, and the horn of Africa. Plasmodium vivax infections are characterized by relapses of malaria arising from persistent liver stages of the parasite (hypnozoites) which can be prevented only by 8-aminoquinoline anti-malarials. Tropical P. vivax relapses at three week intervals if rapidly eliminated anti-malarials are given for treatment, whereas in temperate regions and parts of the sub-tropics P. vivax infections are characterized either by a long incubation or a long-latency period between illness and relapse - in both cases approximating 8-10 months. The epidemiology of the different relapse phenotypes has not been defined adequately despite obvious relevance to malaria control and elimination. The number of sporozoites inoculated by the anopheline mosquito is an important determinant of both the timing and the number of relapses. The intervals between relapses display a remarkable periodicity which has not been explained. Evidence is presented that the proportion of patients who have successive relapses is relatively constant and that the factor which activates hypnozoites and leads to regular interval relapse in vivax malaria is the systemic febrile illness itself. It is proposed that in endemic areas a large proportion of the population harbours latent hypnozoites which can be activated by a systemic illness such as vivax or falciparum malaria. This explains the high rates of vivax following falciparum malaria, the high proportion of heterologous genotypes in relapses, the higher rates of relapse in people living in endemic areas compared with artificial infection studies, and, by facilitating recombination between different genotypes, contributes to P. vivax genetic diversity particularly in low transmission settings. Long-latency P. vivax phenotypes may be more widespread and more prevalent than currently thought. These observations have important implications for the assessment of radical treatment efficacy and for malaria control and elimination.
This issue sees the continuation of the Responsibility to Protect debate with Rebecca Barber addressing the pressing question of whether the concept applies to allow (or require) military intervention to alleviate the consequence of natural disasters. The protection of civilians is very much the theme of the set of three articles arising out of a symposium on International Legal Developments in Darfur, held on 17 December 2008 at Oxford Brookes University. Dawn Sedman introduces the articles more fully, though it is worth noting here that Zeray Yihdego considers the application of international humanitarian law to the conflict, an area of applicable law often overshadowed in discussions of Darfur by international criminal law, particularly the indictment of President Al-Bashir. In this regard Sarah Williams and Lena Sherif explore the arrest warrant issued for the President from the perspective of the traditional immunities of heads of state. Robert Barnidge considers the UN's responses, both military (in the shape of a peace operation) and non-forcible (especially the problems of an arms embargo against the background of genocide/crimes against humanity). One of the questions addressed in the article is if the UN is not going to defend civilians, ought they be given, or least be able to acquire, the means to do it themselves?
