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In this study, strain KK1 isolated from coal tar-contaminated soil was found to be able to mineralize carbazole as a sole source of carbon by radiorespirometric analysis. KK1 cells pregrown on phenanthrene were able to mineralize carbazole much more rapidly than cells pregrown on naphthalene, suggesting a possible close linkage between the pathways for carbazole and phenanthrene catabolism. Also, Rieske-type iron sulfur center sequence of dioxygenase from KK1 was analyzed to evaluate carbazole catabolism by KK1. A gene cloned out from KK1 using a universal dioxygenase primer set was found a dioxygenase for initial catabolism of carbazole based on deduced amino acid sequences. Northern hybridization using the putative carbazole dixoygenase gene fragment as a probe provided the information that catabolism of carbazole might be greatly activated in phenanthrene-grown cells. Analysis of PLFAs extracted from KK1 cells exposed to carbazole revealed that lipids 10:0 3OH, 17:0 cyclo, and 18:0 were representatives produced or significantly increased in response to carbazole. Strain KK1 was identified as Pseudomonas species with 94% confidence when BIOLOG system was applied, as Pseudomonas sp. with over 90% confidence by total cellular compositions of fatty acid, and as Pseudomonas rhodesiae with 99% confidence by 16S rRNA sequence. Accordingly, strain KK1 was identified as Pseudomonas rhodesiae based on combination of the data, and designated Pseudomonas rhodesiae KK1. The phylogenetic tree based on 16S rRNA suggested that strain KK1 was far away in the phylogenetic distance from the strains that can degrade carbazole.
Thirty-eight sera from cattle from a herd in Rhodesia naturally infected with Theileria lawrencei were titrated with the indirect immunofluorescent test against schizont antigens of T parva (Muguga) and T lawrencei from Rhodesia. T lawrencei was found to be indistinguishable from T parva with the test.
Subdural empyema was encountered in 44 African patients in Rhodesia during the period from 1970 to 1974. Subdural empyema seems to be a relatively frequent occurrence in Africans. Sixty-eight per cent of the patients were below the age of 20 years, and males predominated. More than half of the patients had either a history or evidence of an infectious process outside the central nervous system, and about 60% demonstrated focal neurological signs. The diagnosis was confirmed by either surgery or postmortem examination. Cultures of available specimens were positive in 50%. The predominant organisms identified were Streptococcus, followed by Staphylococcus. Surgical treatment consisted mainly of multiple burr holes, drainage of the empyema, and irrigation. The mortality rate in this study was 59%, and some recognizable contributing factors are elaborated. In the discussion the authors compare these observations with pertinent reviews from the literature. Some of these findings correlate well with other reports, whereas other observations are attributed to factors partly inherent in the socio-economic structure of the African population in Rhodesia.
Since 1967, the academic discipline of social and preventive medicine has been taught to medical students at the University of Rhodesia. The emphasis has been on the basic principles underlying the epidemiology of disease and the medical services required to suit the needs of Rhodesia. In 1970, a course in medicalsociology and in 1972, a course in pschology were introduced, and these courses havesupplemented the teaching of medicine in general and of social and preventive medicine in particular. The course is examined in some detail and evidence is submitted concerning the particular content and methodology used in this course of instruction for undergraduates. Reference is also made to a scheme of attachment to medical practitioners and a period spent during the final undergraduate year in a rural situation as part of the faculty programme of instruction in community medicine.
The author, in his capacity as a WHO consultant, undertook a survey of bilharziasis in British West and East Africa and Nyasaland during 1950-51. The information thus obtained has been revised and brought up to date and is recorded in the present article together with similar observations on Northern Rhodesia, which was not visited, and on Southern Rhodesia, the author's own country. In Part I, each country is dealt with in turn. The history of the disease and the findings of field surveys are reviewed, and, wherever possible, personal observations have been included. The fact that the information is of a scanty and incomplete nature is an indication that further local studies in all areas are badly needed. In Part II an attempt is made to survey the situation from the point of view of the various aspects of the subjects-methods of obtaining morbidity data, intensity of infection, effects of the disease on human health, treatment, and the molluscan vectors.
Humans in Rhodesia harbour a wide range of intestinal protozoa. Of the species included, Entamoeba histolytica, Entamoeba coli and Giardia lamblia have previously been recorded. Other species which are either rarely reported or which have previously never been reported from this country, include Trichomonas hominis, Chilomastix mesnili, Enteromonas hominis, Retortamonas intestinalis, Balantidum coli,Entamoeba hartmanni,Entamoeba histolytica Laredo. Endolimax nana, Dientamoeba fragilis and Isospora belli. The importance in Rhodesia of these species, and especially of E. histolytica, is discussed.
Few factual data have been published on the problem of disappearing malaria due to Plasmodium falciparum in Africa. In Southern Rhodesia a surveillance project has been under way since January 1961. The author describes malaria surveillance procedures, methods, organization and costs for the year 1962-63 and presents data relevant to a sparsely populated part of rural Africa where a surveillance visitor can cover a population of only some 3500 by monthly house-to-house visits. Through such visits, and through special surveys, an annual blood examination rate of 25% was achieved in the area at fairly low cost.It was found in the area studied, where 98% of infections are due to P. falciparum, that even Africans who have previously attained a high level of immunity will produce typical fever and associated malaria symptoms on reinfection after several years. Methods of case detection have proved adequately sensitive, despite the problem of asymptomatic carriers and despite the difficulty of obtaining true medical histories. Evidence is produced that much residual low-level transmission occurs indoors, although Anopheles gambiae are found in low density in human dwellings. Drug dosages and preventive treatment are described in detail; to reduce the number of asymptomatic carriers, single-dose presumptive treatment is advocated, at least in the last year of the attack phase. Many of the findings presented will be applicable to other African countries where malaria has been reduced to a low incidence.
One hundred and thirteen patients with missile injuries of the abdomen were seen over a 3-year period at one hospital in Zimbabwe-Rhodesia. The details of these injuries and the results of their treatment are presented. Twenty-four patients died (21 per cent). Twenty of these patients had sustained high velocity missile injuries, 18 had damaged colons and 3 died from major vascular injuries before surgery. Excluding these last 3 patients, the mortality rate for high velocity wounds of the colon was 52 per cent and that for all other patients was 6 per cent (P less than 0.01). More than half the postoperative deaths were due to septicaemia. The importance is stressed is stressed of early and effective resuscitation, including appropriate antibiotic therapy and rapid evacuation to facilities for major surgery.
Pseudomonas rhodesiae KK1 was isolated from a former manufactured-gas plant site, due to its ability to grow rapidly in a mixture of polycyclic aromatic hydrocarbons (PAHs). Radiorespirometric analysis revealed that strain KK1 was found to be able to mineralize anthracene, naphthalene and phenanthrene. Notably, phenanthrene-grown cells were able to mineralize anthracene much more rapidly than naphthalene-grown cells. Comparative analysis of amino acid sequences from 17 randomly selected dioxygenases capable of hydroxylating unactivated aromatic nuclei indicated that the enzymes for catabolism of PAHs, such as naphthalene and phenanthrene, might exist redundantly in strain KK1. Northern hybridization for cells grown on naphthalene or phenanthrene, using the putative naphthalene or phenanthrene dioxygenase gene fragment as a probe, suggested that the enzyme for naphthalene catabolism might share some homology in deduced amino acid sequences with phenanthrene dioxygenases. Also, it was found that three lipids (17:0 cyclo, 18:1 omega7c, 19:0 cyclo) increased in response to both naphthalene and phenanthrene, while the shift of other lipids varied from substrate to substrate.
Optimization studies on the synthesis of isonovalal from alpha-pinene oxide by Pseudomonas rhodesiae CIP 107491 operated in a biphasic medium are presented. Three key parameters are identified. The first is the need for a permeabilization of cells by freezing them and then treating the thawed material with an organic solvent such as chloroform, toluene or diethyl ether. This operation allows both enzyme release into the aqueous phase outside the cells and an improvement in the transport properties of both substrate and product across the cell membrane, strongly increasing reaction rates. The second is that the enzyme alpha-pinene oxide lyase, which exhibits an irreversible inactivation by isonovalal (or a by-product), presents a constant turn-over, i.e., the total product synthesis is proportional to the biomass loading and is close to 108 mmol (16.4 g) isonovalal l(-1) g(-1) biomass. The third phenomenon is that the biphasic system used is not phase-transfer-limited, a feature attributed to the spontaneous formation of an oil-in-water emulsion. It is thus possible to carry out a very efficient process, allowing the recovery of 2.63 mol isonovalal l(-1) (400 g l(-1)) from 25 g biomass l(-1) in 2.5 h, corresponding to an average reaction rate as high as 0.70 mmol min(-1) g(-1) cells (160 g l(-1) h(-1)).
Surveys of snails occurring at water contact points used by rural people in Rhodesia show that transmission of Schistosoma haematobium is very high during the spring and early summer seasons. Although infected snails are found in all seasons, fewest occur in winter and during the heavy rains. It is suggested that the bionomics of this parasite depends on pre-rain transmission because destruction of infected snails during winter reduces the reservoir of infection in the area and also the level of parasitaemia in local schoolchildren.
The value of the erythrocyte acid phosphatase isoenzyme system as a method for blood typing in forensic science in Rhodesia has been evaluated. Three hundred and three blood samples from negroid people were examined. The high incidence of the B phenotype (72%) results in a poor division of the population using this system. The R allele which has been found in other negroid peoples also occurs in the Rhodesian population.
A basic oral health survey was carried out on a random sample of first year African student teachers attending four teachers' colleges in Rhodesia. The number examined and interviewed was 309. Methods and criteria used are those described in the second (1977) edition of the World Health Organization manual Oral health surveys - Basic methods. Prevalences of dental caries were 31.0% for the 142 male students and 59.5% for the 167 female students. The difference is statistically significant (P less than 0.001). Mean DMFTs were 0.74 for men and 2.02 for women. The prevalences of "intense gingivitis" were 52.8% for male students and 34.7% for female students. This difference also is significant (P less than 0.005). The major treatment requirements are for one-surface fillings and prophylaxis with oral hygiene instruction. Dental service utilization is low. Less than 10% of the sample had obtained dental care in the previous 12 months. The main reason for seeking care was pain. Self-assessments of oral health needs were not valid. The stated desire for fillings is greater than for extractions. A need has been demonstrated for dental health education aimed at the prevention of disease and the encouragement, use and demand for quality care services.
The existence of tropical sprue in Africa is controversial. In this paper we present 31 cases seen in Rhodesia over a 15 month period. They have the clinical features, small intestinal morphology, malabsorption pattern, and treatment response of tropical sprue. Other causes of malabsorption, and primary malnutrition, have been excluded. The severity of the clinical state and intestinal malabsorption distinguish these patients from those we have described with tropical enteropathy. The previous work on tropical sprue in Africa is reviewed and it is apparent that, when it has been adequately looked for, it has been found. It is clear that the question of tropical sprue in Africa must be re-examined and that it existence may have hitherto been concealed by the assumption that primary malnutrition is responsible for the high prevalence of deficiency states.
Tropical enteropathy, which may be related to tropical sprue, has been described in many developing countries including parts of Africa. The jejunal changes of enteropathy are seen in Rhodesians of all social and racial categories. Xylose excretion, however, is related to socioeconomic status, but not race. Upper socioeconomic Africans and Europeans excrete significantly more xylose than lower socioeconomic Africans. Vitamin B12 and fat absorption are normal, suggesting predominant involvement of the proximal small intestine. Tropical enteropathy in Rhodesia is similar to that seen in Nigeria but is associated with less malabsorption than is found in the Caribbean, the Indian subcontinent, and South East Asia. The possible aetiological factors are discussed. It is postulated that the lighter exposure of upper class Africans and Europeans to repeated gastrointestinal infections may accound for their superior xylose absorption compared with Africans of low socioeconomic circumstances. It is further suggested that the milder enteropathy seen in Africa may be explained by a lower prevalence of acute gastroenteritis than in experienced elsewhere in the tropics.
A syndrome characterised by the birth of lambs with varying degrees of rigidity of the limbs and spine has been encountered on several occasions in Rhodesia. Outbreaks have occurred in autumn-born lambs from Dorper ewes grazing heavily fertilised Star grass cv No 2 (Cynodon aethiopicus) pastures. The condition appears to be exacerbated by the application of sulphur to the pasture and is partly prevented by the administration of selenium and vitamin E to the ewes before lambing. The aetiology is unknown.
The disruption of veterinary services in the tribal areas of Rhodesia (now Zimbabwe) during seven years of conflict resulted in serious epidemics of disease. The cessation of dipping was followed by the death of an estimated one million cattle from tick-borne disease. Heavy mortality followed the disruption of control measures for trypanosomiasis. Foot-and-mouth disease and anthrax spread widely in the tribal areas. Rabies, normally restricted to areas bordering Botswana and Mocambique, became widespread. A marked increase in human deaths from anthrax and rabies occurred.