Defining the global spatial limits of malaria transmission in 2005.

There is no accurate contemporary global map of the distribution of malaria. We show how guidelines formulated to advise travellers on appropriate chemoprophylaxis for areas of reported Plasmodium falciparum and Plasmodium vivax malaria risk can be used to generate crude spatial limits. We first review and amalgamate information on these guidelines to define malaria risk at national and sub-national administrative boundary levels globally. We then adopt an iterative approach to reduce these extents by applying a series of biological limits imposed by altitude, climate and population density to malaria transmission, specific to the local dominant vector species. Global areas of, and population at risk from, P. falciparum and often-neglected P. vivax malaria are presented for 2005 for all malaria endemic countries. These results reveal that more than 3 billion people were at risk of malaria in 2005.

A global assessment of closed forests, deforestation and malaria risk.

Global environmental change is expected to affect profoundly the transmission of the parasites that cause human malaria. Amongst the anthropogenic drivers of change, deforestation is arguably the most conspicuous, and its rate is projected to increase in the coming decades. The canonical epidemiological understanding is that deforestation increases malaria risk in Africa and the Americas and diminishes it in South-east Asia. Partial support for this position is provided here, through a systematic review of the published literature on deforestation, malaria and the relevant vector bionomics. By using recently updated boundaries for the spatial limits of malaria and remotely-sensed estimates of tree cover, it has been possible to determine the population at risk of malaria in closed forest, at least for those malaria-endemic countries that lie within the main blocks of tropical forest. Closed forests within areas of malaria risk cover approximately 1.5 million km2 in the Amazon region, 1.4 million km2 in Central Africa, 1.2 million km2 in the Western Pacific, and 0.7 million km2 in South-east Asia. The corresponding human populations at risk of malaria within these forests total 11.7 million, 18.7 million, 35.1 million and 70.1 million, respectively. By coupling these numbers with the country-specific rates of deforestation, it has been possible to rank malaria-endemic countries according to their potential for change in the population at risk of malaria, as the result of deforestation. The on-going research aimed at evaluating these relationships more quantitatively, through the Malaria Atlas Project (MAP), is highlighted.

The influence of urbanisation on measures of Plasmodium falciparum infection prevalence in East Africa.

There is a growing interest in the effects of urbanisation in Africa on Plasmodium falciparum risks and disease outcomes. We undertook a review of published and unpublished literature to identify parasite survey data from communities in East Africa. Data were selected to represent the most reliable and contemporary estimates of infection prevalence and were categorised by urban or rural status using a number of approaches. We identified 329 spatially distinct surveys undertaken since 1980 in the sub-region of which 37 were undertaken in urban settlements and 292 in rural settlements. Overall rural settlements reported significantly higher parasite prevalence among children aged 0-14 than urban settlements (on average 10% higher infection rates; p<0.05). No urban settlements recorded parasite prevalence in excess of 75%. In areas of East Africa where climatic conditions are likely to support higher parasite transmission, the rural-urban difference was most marked. There was a significant trend towards documenting higher classes of parasite prevalence in rural compared to urban settlements (p<0.05) and the mean difference between rural and urban samples was 18% (p<0.001). These results further highlight the need to better define urban extents in Africa in order to capture the non-climatic determinants of infection and disease risk and provide a more informed approach to describing the burden of disease across the continent.

Evaluation of different solvent systems for the extraction and fractionation of oleoresins from guajillo peppers.

Dried guajillo peppers were first extracted with four different solvents: ethanol, acetone, ethyl acetate and hexane with the aim of obtaining oleoresins which were further fractionated into red and paprika extracts. Results showed that as the polarity of the solvent increased the amount of pigments extracted also increased. Acetone had good affinity for pungent (capsaicin) compounds. Utilization of these solvents alone did not produce red and paprika oleoresins that meet commercial specifications. Fractionation of acetone extracted oleoresins with ethanol: water (90:10) yielded a precipitate and a solution. The precipitate and solution produced red and paprika extracts that meet pungency and color specifications. It was possible to obtain red and paprika oleoresins from mild guajillo peppers.

[Nocardia isolated from the respiratory tract]. / Estudios sobre nocardias aisladas del aparato respiratorio

Twelve strains of Nocardia isolated from sputa, bronchial washings and pleural fluids, were studied. The classification was based on the following characteristics: a) acid-fastness; 2) ability to disolve crystals of tyrosine and xantine; 3) hydrolysis of casein; 4) growth in dilute gelatin medium (0.4%) and 5) galactose acidification. Direct cultivation of the clinical material in Czapek liquid culture medium without carbon source and containing a paraffin rod (pariffin-bait technic), as well as the routin T.B. sputum digestion and concentration with NaOH solution followed by its cultivation in Loewenstein's medium, were employed for the isolation of Nocardia. The sensitivity of the strains to tuberculostatic drugs was investigated using the Canetti's method, as was the ability to growth in Sabouraud and lactrimel culture media supplemented with 100 mug/ml of rifamycin. Finally the pathogenicity test was carried out by intraperitoneal and intramuscular inoculation in guinea-pigs. All the strains were classified as Nocardia asteroides. Seven starins were isolated from patiens with lung conditions of no nocardial etiology. The diagnosis of nocardiosis of the lung was demonstrated in the remaining five patiens by microscopical observation of Nocardia in clinical specimens, by the repeated cultures obtained from these materials and, finally, by the fact that an improvement of the clinical symptomatology was obtained by sulfa administration.

Estudios sobre nocardias aisladas del aparato respiratorio / [Nocardia isolated from the respiratory tract]

Twelve strains of Nocardia isolated from sputa, bronchial washings and pleural fluids, were studied. The classification was based on the following characteristics: a) acid-fastness; 2) ability to disolve crystals of tyrosine and xantine; 3) hydrolysis of casein; 4) growth in dilute gelatin medium (0.4

) and 5) galactose acidification. Direct cultivation of the clinical material in Czapek liquid culture medium without carbon source and containing a paraffin rod (pariffin-bait technic), as well as the routin T.B. sputum digestion and concentration with NaOH solution followed by its cultivation in Loewenstein’s medium, were employed for the isolation of Nocardia. The sensitivity of the strains to tuberculostatic drugs was investigated using the Canetti’s method, as was the ability to growth in Sabouraud and lactrimel culture media supplemented with 100 mug/ml of rifamycin. Finally the pathogenicity test was carried out by intraperitoneal and intramuscular inoculation in guinea-pigs. All the strains were classified as Nocardia asteroides. Seven starins were isolated from patiens with lung conditions of no nocardial etiology. The diagnosis of nocardiosis of the lung was demonstrated in the remaining five patiens by microscopical observation of Nocardia in clinical specimens, by the repeated cultures obtained from these materials and, finally, by the fact that an improvement of the clinical symptomatology was obtained by sulfa administration.

Estudios sobre nocardias aisladas del aparato respiratorio / [Nocardia isolated from the respiratory tract]

Twelve strains of Nocardia isolated from sputa, bronchial washings and pleural fluids, were studied. The classification was based on the following characteristics: a) acid-fastness; 2) ability to disolve crystals of tyrosine and xantine; 3) hydrolysis of casein; 4) growth in dilute gelatin medium (0.4

) and 5) galactose acidification. Direct cultivation of the clinical material in Czapek liquid culture medium without carbon source and containing a paraffin rod (pariffin-bait technic), as well as the routin T.B. sputum digestion and concentration with NaOH solution followed by its cultivation in Loewensteins medium, were employed for the isolation of Nocardia. The sensitivity of the strains to tuberculostatic drugs was investigated using the Canettis method, as was the ability to growth in Sabouraud and lactrimel culture media supplemented with 100 mug/ml of rifamycin. Finally the pathogenicity test was carried out by intraperitoneal and intramuscular inoculation in guinea-pigs. All the strains were classified as Nocardia asteroides. Seven starins were isolated from patiens with lung conditions of no nocardial etiology. The diagnosis of nocardiosis of the lung was demonstrated in the remaining five patiens by microscopical observation of Nocardia in clinical specimens, by the repeated cultures obtained from these materials and, finally, by the fact that an improvement of the clinical symptomatology was obtained by sulfa administration.