Health and economic impact of HIV/AIDS on South African households: a cohort study.

BACKGROUND: South African households are severely affected by human immunodeficiency virus / acquired immunodeficiency syndrome (HIV/AIDS) but health and economic impacts have not been quantified in controlled cohort studies. METHODS: We compared households with an HIV-infected member, and unaffected neighbouring households, in one rural and one urban area in Free State province, South Africa. Interviews were conducted with one key informant in each household, at baseline and six months later. We studied 1913 members of 404 households, with 94% and 96% follow up, respectively. Household and individual level analyses were done. RESULTS: Members of affected households, compared to members of unaffected households, were independently more likely to be continuously ill (adjusted odds ratio (OR) 2.1, 95% CI 1.3-3.4 at follow up), and to die (adjusted OR 3.4, 95% CI 1.0-11), mainly due to infectious diseases. Government clinics and hospitals were the main sources of health care. Affected households were poorer than unaffected households at baseline (relative income per person 0.61, 95% CI 0.49-0.76). Over six months expenditure and income decreased more rapidly in affected than in unaffected households (baseline-adjusted relative expenditure 0.86, 95% CI 0.75-0.99 and income 0.89, 95% CI 0.75-1.05). Baseline morbidity was independently associated with lower income and expenditure at baseline but not with changes over six months. CONCLUSIONS: HIV/AIDS affects the health and wealth of households as well as infected individuals, aggravating pre-existing poverty.

Correlations of nematodes and soil properties in soybean fields.

Soil samples from 40 soybean fields were collected in 1967 and 1968 and analyzed for nematodes and soil properties. Correlations o f total nematodes, non-stylet nematodes, Dorylaimoidea (excluding Xiphinema americanum), X. americanum, Helicotylenchus pseudorobustus, Tylenchus spp., Aphelenchus avenae, and other groupings of nematodes were made with pH; percentage sand, silt, and clay; percentage organic matter; cation exchange capacity; saturation percentage, and percentage saturation. Organic matter, pH, and cation exchange capacity were most consistently highly correlated with the nematodes. H. pseudorobustus had the most consistently significant correlations with the soil factors. Correlations of nematodes were with more soil factors and were stronger in a wet than in a dry year. The highest numbers of nematodes were usually found in the lighter soils, except in the loamy sand where moisture probably was limiting. In general, soil moisture levels below 20% saturation were probably limiting for most nematodes studied, except for the dorylaims which survived in large numbers in soils with less than 20% saturation.