Thesis (PhD (Epidemiology)-- University of Limpopo, 2011. / Acute poisoning constitutes one of the main reasons why patients visit emergency departments of hospitals. However, the burden and pattern of acute poisoning in African countries are not well established, hence the need for this study. This study was conducted in order to compare the patterns of acute poisoning in three countries, namely, Botswana, South Africa, and Uganda. Specifically, this study examined the similarities and differences in the patterns of occurrence of acute poisoning based on the sociodemographic characteristics of the victims, the toxic agents involved, and the circumstances of the incidents. The study was based on six papers published on the topic. Papers I and II about Botswana covered a period of 24 months (January 2004 - December 2005) and six months (January - June 2005) respectively. The data from Uganda, as reported in Paper III, covered a six-month period (January-June 2005); while studies in South Africa, Papers IV to VI, covered respectively six (January-June 2005) and 18 months (January 2000-June 2001). A re-analysis of data from Papers II to IV was conducted after recoding age category and the grouping of toxic agents. In total, the six Papers reported data on 1780 patients; 54.8% of them were male. The median age was 24 years in Uganda, but as low as 17 years in Botswana and South Africa. In Botswana and South Africa, acute poisoning incidents occurred mostly in children younger than 12 years old, then decreased among teenagers, and increased again among young adults, before decreasing among patients over 30 years old. On the contrary, in Uganda there was that less than 5% of children younger than 12 years who were victims of poisoning. There was an increase in the prevalence of acute poisoning among teenagers and young adults before a decrease occurred among adults over 30 years old. The overall case fatality rate was 2.1 %, ranging from 1.4% in Uganda, 2.4% in South Africa, to 2.6% in Botswana. With regard to similarities across the three countries, it was found that among teenagers, girls committed more deliberate self-poisoning than boys; while in young adults, men committed more self-poisoning than women. With regard to toxic agents, household products were involved in fatal Page 9 of 136 outcomes in all three countries; while agrichemicals were more involved in deliberate than accidental poisonings; food poisoning affected more females than males. With regard to disparities across the three countries, the age and gender of the victims, the circumstances of the incidents and the types of toxic agents played a significant role. With regard to gender, the majority of the victims were males in Uganda, females in South Africa; while in Botswana, females and males were affected equally. Among teenagers, the toxic agents most involved in the poisoning incidents were pharmaceuticals in Botswana; household chemicals in South Africa; but agrichemicals in Uganda. While the majority of incidents happened by accident in Botswana and South Africa, being respectively 76.7% and 59.1%; in Uganda, 64.5% of acute poisoning cases were deliberate self¬poisoning. Deliberate self-poisoning was responsible for 50% of deaths in Uganda, 30% in South Africa, but no death in Botswana. The majority of deaths occurred among teenagers in South Africa; in Uganda it was among adults over 30years; while in Botswana, the majority of deaths were distributed almost equally amongst children younger than 12years old and young adults. Diverse products were involved in fatal outcomes. In South Africa, pharmaceuticals, particularly drugs of abuse, cocaine and marijuana; as well as carbon monoxide, and organophosphates were involved in fatalities. While, in Botswana, the products involved were paraffin, traditional medicines, pharmaceuticals, food poisoning, plants, and snake envenomation. In contrast, in Uganda, alcohol intoxication, organophosphates, carbon monoxide, and some unspecified household products lead to fatalities. Household chemicals were involved in the deaths of victims in all three countries; but the extent of their involvement differed from country to country. This group of products was responsible of 75% of deaths in Uganda, half of deaths in South Africa, and in a third of deaths in Botswana. Agrichemicals were involved in the deaths of victims in Uganda and South Africa, but not in Botswana. They were involved in a quarter of deaths in Uganda and 10% of deaths in South Africa. Page 10 of 136 Plants and traditional medicines were involved in two-thirds of the deaths only in Botswana; while pharmaceuticals were involved in 40% of fatal outcomes only in South Africa. In conclusion, the contextual factors of each country led to a pattern of acute poisoning that showed some similarities with regard to the distribution of deliberate self-poisoning among females, teenagers, and young adult victims. However, there were disparities relating to the differential access to toxic agents, based on the age and gender of the victims. Moreover, though the case fatality rate was similar across the three countries, the distribution of deaths based on age, gender, circumstances of poisoning and types of toxic agents involved differed among the three countries. These findings suggest that multifaceted interventions should be implemented including policy development, enforcement of the existing legislation, and the establishment of a surveillance mechanism, in-service training of clinicians and revision of treatment guidelines. These interventions should be tailored to meet the specific realities of each country.

Graduation date: 1995

Disputats, Stockholm, 2005. / Härtill 5 uppsatser. Med sammanfattning på engelska.

Thèse--Univ. de Paris. École supérieure de pharmacie. Ann ́1911-1912. No. 8. / Includes bibliographical footnotes.

Thesis (D.P.H.)--University of Michigan, 1916. / "Reprint from the Journal of laboratory and clinical medicine, vol. I, no. 7." Bibliography: p. 10-11.

Cadmium, one of the trace metals, has, in the last two to three decades, become increasingly important in both industrial and biological fields. The recognition of cadmium as a serious health hazard has led to a closer examination of its properties and biochemical effects. Cadmium, an element of ata:nic number 48, atomic weight 112.41 and valency 2, is a soft 'White lustrous metal belonging to the second sub-group of the Periodic Table. It has a boiling point of 768°c, melting point of 321°0, is remarkably volatile for a heavy metal, and exists naturaly as a mixture of eight isotopes, constituting 2 x 10-5% of the earth's crust. Extraction of cadmium is by distillation from zinc ores. The electron configuration of cadmium is 4d105s2, and it forms simple bipositive cations only. There are no ligand field stabilization effects in cadmium ions, and the stereochemistry is, therefore, determined solely by size and electrostatic and covalent bonding forces.s Cadmium chloride shows octahedral co-ordination.

Road runoff contains a complex mixture of contaminants including metals, anions, and hydrocarbons. This runoff discharges into natural water courses which are often small streams. The concentration of these chemicals in the drainage water and receiving stream depends on a number of site specific characteristics such as traffic volume, area of road drained and size of the stream. It was postulated that these pollutants have a deleterious affect on macroinvertebrate community structure which would result in subsequent effects on macroinvertebrate function (i. e. litter processing). Further, it was hypothesised that impacts would be greatest in small streams, receiving drainage waters from large areas of heavily used motorway and that only a limited number of chemicals would be responsible for any effects. Field surveys demonstrated that macroinvertebrate community structure and function was impacted at one of the three sites studied, namely Pigeon Bridge Brook. The downstream station at this site received motorway runoff drainage from the largest area of road surface, was the smallest stream and had the highest metal and hydrocarbon concentrations in both stream water and sediments (Maltby et al., 1995a). Macroinvertebrate species richness and diversity were significantly reduced below the discharge. Species generally considered 'sensitive' to pollutants such as stoneflies, gammarids, molluscs and trichopterans were reduced in relative abundance whilst more 'tolerant' opportunistic species such as chironomids and tubificid worms increased in relative abundance downstream of the discharge. An assessment of the trophic composition of the community (i. e. functional feeding groups) indicated that there was a differential loss of functional groups, with significantly lower relative abundances of shredders and scrapers and an increase in collectors downstream of the motorway discharge. The changes in both the structure and trophic biology of the macroinvertebrate community resulted in a significant reduction in macroinvertebratemediated leaf processing downstream of the motorway discharge. Although field surveys indicated macroinvertebrate community structure and function were negatively impacted below the motorway discharge at Pigeon Bridge Brook they cannot establish causal relationships. In-situ and laboratory studies were therefore performed to address the mechanistic basis for the impact. In-situ and laboratory lethality exposures did not fully explain the field distribution of the species used in toxicological studies; Gammarus pulex (L. ), Nemoura cinerea (Retz. ), Potamopyrgus jenkinsi (Smith), Chironomus riparius (Meigen) and Tubifex tubifex (Müller). In acute lethality tests stream water from Pigeon Bridge Brook was not toxic to any of the species. In contrast, G. pulex and N. cinerea showed slight, but significant mortality when exposed to downstream sediment from this site. Sediment manipulation and sediment solvent and acid extract exposures indicated that the solvent extractable fraction of the sediment was responsible for this toxicity to G. pulex but not to N. cinerea. These results indicated that aromatic hydrocarbons in the sediment may be responsible for the toxicity and this has subsequently been shown to be the case (Maltby et al., 1995b). ifi Since lethality studies did not fully explain field -distributions of the animals sub-lethal toxicity avoidance behaviour tests were employed using sediment, manipulated sediments and sediment extracts. The sensitivity to downstream field sediment, indicated by avoidance decreased in the order P. jenkinsi > G. pulex > C. riparius> T. tubifex = N. cinerea and to a solvent extract of this sediment in the order G. pulex > P. jenkinsi > C. riparius > N. cinerea > T. tubifex. Acid sediment extracts and solvent extracted sediments induced no avoidance responses in these animals. Gammarus pulex was thought to be the dominant shredding macroinvertebrate at Pigeon Bridge Brook. Reductions in macroinvertebrate-mediated leaf processing could therefore be the result of sub-lethal effects of motorway contamination on the feeding activity of this species. In-situ exposures indicated that the consumption of leaf material by G. pulex was reduced at the downstream station and laboratory exposures indicated this was principally a result of sediment toxicity. Sediment extract exposures indicated that the solvent extractable fraction was again responsible for the majority of this effect. Accumulation of metals and aromatic hydrocarbons on the leaf material had very little effect on leaf consumption or choice. However, reduced colonisation of leaf material by aquatic hyphomycetes reduced both leaf choice and consumption when the material was conditioned at the downstream station. The major uptake route of aromatic hydrocarbons by G. pulex was via aqueous sources and not from food. In conclusion motorway derived contamination in small streams has both lethal and sublethal effects on some macroinvertebrates. This affects macroinvertebrate structural and trophic characteristics which subsequently have a deleterious effect on important ecosystem functions.

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