Higher protein intake is associated with increased risk for incident end-stage renal disease among blacks with diabetes in the Southern Community Cohort Study.

BACKGROUND AND AIMS: Diabetes, a risk factor for end-stage renal disease (ESRD), is associated with impaired protein metabolism. We investigated whether protein intake is associated with ESRD and whether the risk is higher among blacks with diabetes. METHODS AND RESULTS: We conducted a nested case-control study of ESRD within the Southern Community Cohort Study, a prospective study of low-income blacks and whites in the southeastern US (2002-2009). Through 2012, 1057 incident ESRD cases were identified by linkage with the United States Renal Data System and matched to 3198 controls by age, sex, and race. Dietary intakes were assessed from a validated food frequency questionnaire at baseline. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed from logistic regression models that included matching variables, BMI, education, income, hypertension, total energy intake, and percent energy from saturated and polyunsaturated fatty acids. Mean (±SD) daily energy intake from protein was higher among ESRD cases than controls (15.7 ± 3.3 vs. 15.1 ± 3.1%, P < 0.0001). For a 1% increase in percent energy intake from protein, the adjusted ORs (95% CIs) for ESRD were 1.06 (1.02-1.10) for blacks with diabetes, 1.02 (0.98-1.06) for blacks without diabetes, 0.99 (0.90-1.09) for whites with diabetes and 0.94 (0.84-1.06) for whites without diabetes. Protein intake in g/kg/day was also associated with ESRD (4th vs. 1st quartile OR = 1.76; 95% CI: 1.17-2.65). CONCLUSION: Our results raise the possibility that among blacks with diabetes, increased dietary protein is associated with increased incidence of ESRD. Studies on how protein intake and metabolism affect ESRD are needed.

Intake of polyunsaturated fat in relation to mortality among statin users and non-users in the Southern Community Cohort Study.

BACKGROUND AND AIMS: Consumption of polyunsaturated fatty acids (PUFA), especially the n3-series, may protect against cardiovascular disease (CVD), but recent randomized studies have failed to demonstrate these benefits. One of the prevailing hypotheses is that PUFA intake may not confer benefits beyond those provided by statins, but studies comparing statin users to non-users with regard to effects of PUFA are lacking. METHODS AND RESULTS: Black and white men and women (n = 69,559) in the Southern Community Cohort Study were studied. Cox regression models adjusting for age, sex, race, BMI, recruitment site, education, income, smoking, diabetes, and dietary variables were used. RESULTS: At baseline the mean ± SD age was 52 ± 9 years, 60% of participants were women, 54% had hypertension and 16% used statins. We observed modest inverse associations between n3-PUFA and n6-PUFA intake with mortality among non-statin users but not among statin users. In adjusted analyses, the HRs (95% CIs) for all-cause mortality (6,396 deaths over a median of 6.4 years) comparing the highest to the lowest quintile were 0.90 (0.82-1.00) for n3-PUFA and 0.80 (0.70-0.92) for n6-PUFA among non-statin users, whereas they were 1.06 (0.87-1.28) and 0.96 (0.78-1.19) for n3-PUFA and n6-PUFA, respectively, among statin users. CONCLUSIONS: Our results suggest potential benefits of PUFA consumption on mortality which are only apparent in the absence of statin therapy. It seems prudent to consider the potential benefit of PUFA consumption in the primary prevention of CVD among patients who are not candidates for statin therapy but are at increased risk for CVD and mortality.

The association between LRP-1 variants and chylomicron uptake after a high fat meal.

BACKGROUND AND AIMS: In vitro studies suggest that low density lipoprotein receptor-related protein 1 (LRP1) plays a role in the secondary uptake of chylomicrons. In addition, in vivo studies using LRP-1 knockout mice show these animals exhibit delayed chylomicron clearance. Whether this is true in humans is unknown. We aimed to determine whether genetic variants in LRP-1 are associated with postprandial chylomicron uptake in humans given an oral fat challenge. METHODS AND RESULTS: As many as 817 men and women (mean age +/- standard deviation = 48.4 +/- 16.4 years) forming the study population for the Genetics of Lipid Lowering Drugs Network (GOLDN) study ingested an oral fat load of 700 kilocalories per m² of body surface area at 83% fat, after an 8-h fast. Chylomicrons were measured by nuclear resonance spectroscopy (NMR) at fasting, and 3.5 and 6 h after the meal. 26 Single nucleotide polymorphisms (SNPs) in the LRP-1 gene were genotyped on the Affymetrix 6.0 array. Chylomicrons were, as expected, zero at fasting. Mixed linear models adjusted for age, sex, study site and pedigree tested for associations between LRP-1 SNPs and changes in chylomicron concentrations 3.5-6 h. A gene-based test across all 26 SNPs was conducted which corrected for the linkage disequilibrium (LD) between SNPs. 11 LRP-1 SNPs were significantly associated with the change in chylomicron concentration correction for multiple testing (Q < 0.05). The subsequent gene-based test, was also significant (P = 0.01). CONCLUSION: These results require replication but strongly indicate the role of LRP1 in postprandial lipoprotein uptake and/or clearance.

Lipoprotein receptor-related protein 1 variants and dietary fatty acids: meta-analysis of European origin and African American studies.

OBJECTIVE: Low-density lipoprotein-related receptor protein 1 (LRP1) is a multi-functional endocytic receptor and signaling molecule that is expressed in adipose and the hypothalamus. Evidence for a role of LRP1 in adiposity is accumulating from animal and in vitro models, but data from human studies are limited. The study objectives were to evaluate (i) relationships between LRP1 genotype and anthropometric traits, and (ii) whether these relationships were modified by dietary fatty acids. DESIGN AND METHODS: We conducted race/ethnic-specific meta-analyses using data from 14 studies of US and European whites and 4 of African Americans to evaluate associations of dietary fatty acids and LRP1 genotypes with body mass index (BMI), waist circumference and hip circumference, as well as interactions between dietary fatty acids and LRP1 genotypes. Seven single-nucleotide polymorphisms (SNPs) of LRP1 were evaluated in whites (N up to 42 000) and twelve SNPs in African Americans (N up to 5800). RESULTS: After adjustment for age, sex and population substructure if relevant, for each one unit greater intake of percentage of energy from saturated fat (SFA), BMI was 0.104 kg m(-2) greater, waist was 0.305 cm larger and hip was 0.168 cm larger (all P<0.0001). Other fatty acids were not associated with outcomes. The association of SFA with outcomes varied by genotype at rs2306692 (genotyped in four studies of whites), where the magnitude of the association of SFA intake with each outcome was greater per additional copy of the T allele: 0.107 kg m(-2) greater for BMI (interaction P=0.0001), 0.267 cm for waist (interaction P=0.001) and 0.21 cm for hip (interaction P=0.001). No other significant interactions were observed. CONCLUSION: Dietary SFA and LRP1 genotype may interactively influence anthropometric traits. Further exploration of this, and other diet x genotype interactions, may improve understanding of interindividual variability in the relationships of dietary factors with anthropometric traits.

Preliminary evidence of genetic determinants of adiponectin response to fenofibrate in the Genetics of Lipid Lowering Drugs and Diet Network.

BACKGROUND AND AIMS: Adiponectin is an adipose-secreted protein that has been linked to changes in insulin sensitivity, high-density lipoprotein cholesterol levels, and inflammatory patterns. Although fenofibrate therapy can raise adiponectin levels, treatment response is heterogeneous and heritable, suggesting a role for genetic mediators. This is the first genome-wide association study of fenofibrate effects on circulating adiponectin. METHODS AND RESULTS: Plasma adiponectin was measured in participants of the Genetics of Lipid Lowering Drugs and Diet Network (n = 793) before and after a 3-week daily treatment with 160 mg of fenofibrate. Associations between variants on the Affymetrix Genome-Wide Human SNP Array 6.0 and adiponectin were assessed using mixed linear models, adjusted for age, sex, site, and family. We observed a statistically significant (P = 5 × 10⁻8) association between rs2384207 in 12q24, a region previously linked to several metabolic traits, and the fenofibrate-induced change in circulating adiponectin. Additionally, our genome-wide analysis of baseline adiponectin levels replicated the previously reported association with CDH13 and suggested novel associations with markers near the PCK1, ZBP1, TMEM18, and SCUBE1 genes. The findings from the single marker tests were corroborated in gene-based analyses. Biological pathway analyses suggested a borderline significant association between the EGF receptor signaling pathway and baseline adiponectin levels. CONCLUSIONS: We present preliminary evidence linking several biologically relevant genetic variants to adiponectin levels at baseline and in response to fenofibrate therapy. Our findings provide support for fine-mapping of the 12q24 region to investigate the shared biological mechanisms underlying levels of circulating adiponectin and susceptibility to metabolic disease.

A genotype risk score predicts type 2 diabetes from young adulthood: the CARDIA study.

AIMS/HYPOTHESIS: Genotype does not change over the life course and may thus facilitate earlier identification of individuals at high risk for type 2 diabetes. We hypothesised that a genotype score predicts incident type 2 diabetes from young adulthood and improves diabetes prediction models based on clinical risk factors alone. METHODS: The Coronary Artery Risk Development in Young Adults (CARDIA) study followed young adults (aged 18-30 years, mean age 25) serially into middle adulthood. We used Cox regression to build nested prediction models for incident type 2 diabetes based on clinical risk factors assessed in young adulthood (age, sex, race, parental history of diabetes, BMI, mean arterial pressure, fasting glucose, HDL-cholesterol and triacylglyercol), without and with a 38-variant genotype score. Models were compared with C statistics and continuous net reclassification improvement indices (NRI). RESULTS: Of 2,439 participants, 830 (34%) were black and 249 (10%) had a BMI ≥ 30 kg/m(2) at baseline. Over a mean 23.9 years of follow-up, 215 (8.8%) participants developed type 2 diabetes. The genotype score significantly predicted incident diabetes in all models, with an HR of 1.08 per risk allele (95% CI 1.04, 1.13) in the full model. The addition of the score to the full model modestly improved reclassification (continuous NRI 0.285; 95% CI 0.126, 0.433) but not discrimination (C statistics 0.824 and 0.829 in full models with and without score). Race-stratified analyses were similar. CONCLUSIONS/INTERPRETATION: Knowledge of genotype predicts type 2 diabetes over 25 years in white and black young adults but may not improve prediction over routine clinical measurements.

Dietary Carbohydrate Modifies the Inverse Association Between Saturated Fat Intake and Cholesterol on Very Low-Density Lipoproteins.

We aimed to investigate the relationship between dietary saturated fat on fasting triglyceride (TG) and cholesterol levels, and any mediation of this relationship by dietary carbohydrate intake. Men and women in the NHLBI Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) study (n = 1036, mean age ± SD = 49 ± 16 y) were included. Mixed linear models were run with saturated fat as a predictor variable and fasting TG, very low density lipoprotein cholesterol (VLDL-C), low density cholesterol (LDL-C) and high density cholesterol (HDL-C) as separate outcome variables. Subsequent models were run which included dietary carbohydrate as a predictor variable, and an interaction term between saturated fat and carbohydrate. All models controlled for age, sex, BMI, blood pressure and dietary covariates. In models that included only saturated fat as a predictor, saturated fat did not show significant associations with fasting lipids. When carbohydrate intake and an interaction term between carbohydrates and saturated fat intake was included, carbohydrate intake did not associate with lipids, but there was an inverse relationship between saturated fat intake and VLDL-C (P = 0.01) with a significant interaction (P = 0.01) between saturated fat and carbohydrate with regard to fasting VLDL-C concentrations. Similar results were observed for fasting TG levels. We conclude that, when controlling for carbohydrate intake, higher saturated fat was associated with lower VLDL-C and TGs. This was not the case at higher intakes of carbohydrate. This has important implications for dietary advice aimed at reducing TG and VLDL-C levels.

Prevalence of overweight and obesity in young adults in Uganda.

BACKGROUND: Obesity in young adults is rising and predicts diabetes and cardiovascular diseases later in life. Data on prevalence and determinants of obesity in developing countries are needed for primary prevention. OBJECTIVES: To determine the prevalence of overweight and obesity in young adults in urban (Kampala city) and rural areas (Kamuli District) of Uganda. METHODS: Cross-sectional survey of 683 randomly selected young adults aged 18-30 years. Obesity was defined as body mass index (BMI) > 30 kg/m(2) and overweight as BMI > 25 kg/m(2). Distribution of BMI by socio-demographic characteristics was determined. RESULTS: Of the 683 participants, 50.5% were female and 53.2% were from Kampala. The overall prevalence of obesity and overweight was 2.3% and 10.4%, respectively. The prevalence of obesity was 4.4% in Kampala and 0% in Kamuli while the prevalence of overweight was 10.2% and 10.6% in Kampala and Kamuli, respectively. Compared to males, females were more likely to be obese (2.9% vs. 1.8%) or overweight (17.4% vs. 3.3%). Residing in the city, alcohol consumption, smoking, non-engagement in sports activities, commuting to school by taxi or private vehicle and being from a rich family were the main factors significantly associated (P<0.05) with obesity. Being female (p = 0.0001) and not engaging in any sports activities (P = 0.002) were two factors significantly associated with being overweight. CONCLUSION: We observed significant gender differences in the prevalence of obesity among young adults in Uganda. Contrary to expectation, we did not observe significant rural-urban differences in the prevalence of overweight.

ADAM17_i33708A>G polymorphism interacts with dietary n-6 polyunsaturated fatty acids to modulate obesity risk in the Genetics of Lipid Lowering Drugs and Diet Network study.

BACKGROUND AND AIMS: The disintegrin and metalloproteinase ADAM17, also known as tumor necrosis factor alpha converting enzyme, is expressed in adipocytes. Importantly, elevated levels of ADAM17 expression have been linked to obesity and insulin resistance. Therefore, the aim of this study was to evaluate the association of six ADAM17 single nucleotide polymorphisms (SNPs) (m1254A>G, i14121C>A, i33708A>G, i48827A>C, i53440C>T, and i62781G>T) with insulin-resistance phenotypes and obesity risk, and their potential interactions with dietary polyunsaturated fatty acids (PUFA). METHODS AND RESULTS: ADAM17 SNPs were genotyped in 936 subjects (448 men/488 women) who participated in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study. Anthropometrical and biochemical measurements were determined by standard procedures. PUFA intake was estimated using a validated questionnaire. G allele carriers at the ADAM17_m1254A>G polymorphism exhibited significantly higher risk of obesity (P=0.003), were shorter (P=0.017), had higher insulin (P=0.016), and lower HDL-C concentrations (P=0.027) than AA subjects. For the ADAM17_i33708A>G SNP, homozygotes for the A allele displayed higher risk of obesity (P=0.001), were heavier (P=0.011), had higher BMI (P=0.005), and higher waist measurements (P=0.023) than GG subjects. A significant gene-diet interaction was found (P=0.030), in which the deleterious association of the i33708A allele with obesity was observed in subjects with low intakes from (n-6) PUFA (P<0.001), whereas no differences in obesity risk were seen among subjects with high (n-6) PUFA intake (P>0.5) CONCLUSION: These findings support that ADAM17 (m1254A>G and i33708A>G) SNPs may contribute to obesity risk. For the ADAM17_i33708A>G SNP, this risk may be further modulated by (n-6) PUFA intake.

The effect of a novel intergenic polymorphism (rs11774572) on HDL-cholesterol concentrations depends on TaqIB polymorphism in the cholesterol ester transfer protein gene.

BACKGROUND AND AIMS: Several genes have been shown to individually affect plasma lipoprotein metabolism in humans. Studies on gene-gene interactions could offer more insight into how genes affect lipid metabolism and may be useful in predicting lipid concentrations. We tested for gene-gene interactions between TaqIB SNP in the cholesterol ester transfer protein (CETP) and three novel single nucleotide polymorphisms (SNPs), namely rs11774572, rs7819412 and rs6995374 for their effect on metabolic syndrome (MetS) components and related traits. METHODS AND RESULTS: The aforementioned SNPs were genotyped in 1002 subjects who participated in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study. Lipids were measured by standard procedures and lipoprotein subfractions, by proton nuclear magnetic resonance spectroscopy. Polymorphism rs11774572 was significantly associated with MetS (P=0.020), mainly driven by the association of the C allele with lower HDL-C (P=0.043) and higher triglycerides (P=0.049) and insulin (P=0.040) concentrations than TT subjects. A significant interaction between SNPs rs11774572 and CETP-TaqIB SNPs was found for HDL-C concentrations (P=0.006) and for HDL (P=0.008) and LDL particle sizes (P=0.009), small LDL (P=0.004), and VLDL concentrations (P=0.021), in which TT homozygotes displayed higher HDL-C concentrations and for HDL and LDL particle sizes, and lower small LDL and VLDL concentrations than C carriers, if they were CETP B2 allele carriers (P values ranging from <0.001 to 0.001). CONCLUSIONS: The rs11774572 polymorphism may play a role in the dyslipidemia that characterizes MetS. The interaction between rs11774572 and CETP-TaqIB SNPs on HDL-C concentrations provides some insights into the underlying mechanisms.

A study of risk factors associated with Newcastle disease epidemics in village free-range chickens in Uganda.

A prospective study of risk factors associated with outbreaks of Newcastle disease (ND) in indigenous free-range chickens was carried out in three agro-ecological zones in eastern Uganda. Sixty households keeping chickens were randomly selected and studied from March 2004 to February 2005, covering rainy and dry seasons. Data on ND outbreaks, risk factors and flock dynamics were collected using an interviewer-administered questionnaire, while ND outbreaks were confirmed by haemagglutination inhibition test. Multivariate survival analyses were performed to identify the risk factors for Newcastle disease outbreaks. Although the survival time against ND was longer (> 100 days) in the dry compared to the rainy season, incidence in the two seasons was not significantly different (p > 0.05). None of the factors investigated was significantly associated with ND. However, purchasing of restocking chickens from the market and neighbourhood (hazard ratio [HR] = 1.79; 95% confidence interval [CI] 0.89-3.60), the presence of migratory wild birds (HR = 1.70; 95% CI 0.65-4.48) and being in agro-ecological zone 1 (HR = 1.48; 95% CI 0.66-3.36) showed a positive but non-significant association with risk for ND. To understand the roles of other domestic poultry species in the epidemiology of ND in rural free-range chickens, virus isolation and molecular characterization of isolates in addition to more prospective cohort studies with a larger sample size and similarly long period of follow-up are needed.

The prevalence of serum antibodies to tick-borne infections in Mbale District, Uganda: the effect of agro-ecological zone, grazing management and age of cattle.

Between August and October 2000, a cross-sectional study was conducted in smallholder dairy farms in Mbale District, Uganda to assess the prevalence of ticks and tick-borne diseases under different grazing systems and agro-ecological zones and understand the circumstances under which farmers operated. A questionnaire was administered to obtain information on dairy farm circumstances and practices. A total of 102 farms were visited and sera and ticks were collected from 478 animals. Sero-prevalence of tick-borne diseases was determined using an enzyme-linked immunoassay. Acaricides were used indiscriminately but the intensity of their use varied with the grazing system and zone. Cattle from different farms mixed for various reasons. During the dry seasons farmers have to get additional fodder from outside their farms that can result in importation of ticks. The prevalence of ticks and serum antibodies to tick-borne infections differed across the grazing systems and zones. The highest serum antibody prevalence (>60%) was recorded in the lowland zone under the free range and tethering grazing systems. The lowest tick challenge and serum antibody levels (<50%) were recorded in the midland and upland zones under a zero-grazing system. These findings suggest that endemic stability to East Coast Fever, babesiosis and anaplasmosis is most likely to have existed in the lowland zone, particularly, under the tethering and free-range grazing systems. Also, endemic stability for babesiosis existed in the upland zones. Endemic instability for East Coast Fever existed in the midland and upland zones. These structured observational studies are instrumental in planning of control strategies for ticks and tick borne diseases since production systems and the cattle population at high risk of the diseases in the district have been identified.

Individual saturated fatty acids and nonfatal acute myocardial infarction in Costa Rica.

BACKGROUND: Epidemiological studies on the effect of individual saturated fatty acids (SFAs) on cardiovascular disease, especially in developing countries with different dietary patterns, are scarce. OBJECTIVE: To determine the risk of nonfatal acute myocardial infarction (MI) associated with consumption of individual SFAs and their food sources in Costa Rica. DESIGN: The cases (n=485) were survivors of a first acute MI and were matched by age, sex and area of residence to population controls (n=508). Data on anthropometrical measurements, lifestyle and diet were collected using interviewer-administered questionnaires. RESULTS: In analyses adjusted for confounders, consumption of total and individual SFAs was associated with an increased risk of MI. The odds ratio (OR) (95% confidence intervals) for 1% increase in energy from total saturated fat was 1.12 (1.03-1.21) while it was 1.51 (1.03-2.22) for lauric acid+myristic acid, 1.14 (1.01-1.30) for palmitic acid and 2.00 (1.34-3.00) for stearic acid. Although lauric and myristic acids were associated with increased risk of MI, they were consumed in small amounts and most of the saturated fat (87%) came from palmitic and stearic acids, which derived mainly from red meat and fried foods. Consumption of cheese (1-2 vs 0 servings/day) was associated with increased risk of MI (OR=3.07; 95% confidence interval: 1.74-5.39; P for trend <0.0001), while consumption of low-fat milk was not. CONCLUSION: Increased consumption of total and individual SFAs is associated with increased risk of MI. Lauric, myristic and stearic acids were more potent than palmitic acid.

Application of the method of triads to evaluate the performance of food frequency questionnaires and biomarkers as indicators of long-term dietary intake.

Little is documented about the performance of the food frequency questionnaire (FFQ) in US minority groups and in populations in developing countries. The authors applied a novel technique, the method of triads, to assess the validity and reproducibility of the FFQ among Hispanics. The subjects were men (n = 78) and women (n = 42) living in Costa Rica. Seven 24-hour dietary recalls and two FFQ interviews (12 months apart) were conducted between 1995 and 1998 to estimate dietary intake during the past year. Plasma and adipose tissue samples were collected from all subjects. Validity coefficients, which measure the correlation between observed and "true" dietary intake, were also estimated. The median validity coefficients for tocopherols and carotenoids estimated by dietary recall, the average of the two FFQs, and plasma were 0.71, 0.60, and 0.52, respectively. Compared with adipose tissue, plasma was a superior biomarker for carotenoids and tocopherols. Adipose tissue was a poor biomarker for saturated and monounsaturated fatty acids but performed well for polyunsaturated fatty acids (validity coefficients, 0.45-1.01) and lycopene (validity coefficient, 0.51). This study also showed that biomarkers did not perform better than the FFQ and that they should be used to complement the FFQ rather than substitute for it.

Risk factors for Brucella seropositivity in goat herds in eastern and western Uganda.

Cross-sectional prevalences and risk factors for Brucella seropositivity in goats in eastern and western Uganda were investigated. Serum was collected from 1518 goats randomly selected from 145 herds which had been identified using multistage sampling. The brucellosis card test (CT) and the Brucella melitensis tube-agglutination test (TAT) were used in parallel to detect antibodies against B. abortus and B. melitensis, respectively. Interviewer-administered questionnaires were used to collect information on goat health and management. This information was used in multivariable logistic-regression models to determine the risk factors for Brucella seropositivity in goat herds. For each analysis, a herd was considered positive if at least one goat in the herd tested positive for antibodies against Brucella and negative if none was positive. Four percent (55/1480) of the goats screened with the CT had antibodies against Brucella. The reactors were distributed in 13% (19/145) of the herds. The most-important herd-level risk factors identified were use of a hired caretaker as the primary manager of the operation compared to owner/family members (adjusted odds ratio (OR)=8.1; 95% CI 1.6, 39.7), keeping sheep in addition to goats (OR=6.0; CI 1.5, 23.7) compared to having no sheep, and free browsing (OR=4.7; 95% CI 1.0, 20.7) when compared to tethering or zero-grazing. Using the TAT, 10% (141/1446) of the goats tested positive. The positives were distributed in 43% (63/145) of the herds. Free browsing (OR=6.7; 95% CI 2.7, 16.9) when compared to tethering or zero-grazing and lack of veterinary care (OR=2.9; CI 1.3, 6.7) were the most-important factors identified in the multivariable model for B. melitensis herd seropositivity. To explore/reduce the risk of misclassification in a secondary analysis, herds were reclassified as positive if at least one goat tested positive on both tests and negative if none of the goats was positive on any of the two tests. Using this classification, 2% (30/1320; 95% CI 2, 3%) of the goats tested positive resulting in 13% (12/93) of the herds being positive. The distribution of the above risk factors by brucellosis herd-status (as defined by the second criterion) is also presented.

Attempts to control haemonchosis in grazing ewes by vaccination with gut membrane proteins of the parasite.

A vaccination trial was conducted to evaluate the potential benefit of Haemonchus contortus gut membrane proteins as vaccine antigens under field conditions in Louisiana. The trial was conducted in the summer of 1996 in a flock of ewes grazing pasture naturally infected with H. contortus. Ewes were randomly assigned to three treatment groups (vaccine, adjuvant only, and saline) and fecal egg counts (FEC, measured as eggs per gram of feces), packed cell volumes (PCV), and antibody levels were monitored fortnightly for 12 weeks. It was shown by FEC that there were large individual variations in susceptibility to H. contortus in both vaccinated and non-vaccinated sheep, a finding which could have masked differences between treatments when analyzed by conventional statistical methods. Based on their egg counts before the period when the vaccination could have had an effect, all ewes were categorized as 'susceptible' or 'relatively resistant'. The significance of differences between FEC, PCV and antibody responses of vaccinated and control sheep were tested separately for the 'susceptible' and 'relatively resistant' category. The 'susceptible' vaccinates shed 65% fewer worm eggs during the period when the vaccine could have had an effect, but the difference was only significant on Week 6 post-vaccination. In these experiments, it was difficult to completely exclude the confounding effect of having 'relatively resistant' sheep in the control group. More studies are needed to further evaluate H11 and H-gal-GP antigens under field conditions.

Risk factors for fecal shedding of Salmonella in 91 US dairy herds in 1996.

In 1996, data on management practices used on US dairy operations were collected and analyzed for association with fecal shedding of Salmonella by dairy cows. A total of 4299 fecal samples from 91 herds was cultured for Salmonella isolation. Herd-size (adjusted odds ratios (OR) = 5.8, 95% CI 1.1, 31.3), region (OR = 5.7, CI 1.4, 23.5), use of flush water systems (OR = 3.5, CI 0.9, 14.7), and feeding brewers' products to lactating cows (OR = 3.4, CI 0.9, 12.9) were identified as the most important predictive risk factors. The population attributable risks (PARs) for herd-size, region, flush water system, and feeding brewers' products to lactating cows were 0.76, 0.46, 0.37, and 0.42, respectively. The estimated PAR for all four risk factors combined was 0.95. The effects of these factors need to be more-closely evaluated in more-controlled studies, in order to develop intervention programs that reduce Salmonella shedding.

Tsetse survey in Mukono district, south-east Uganda: population structure, distribution and blood meal status.

The population structure, feeding state and distribution of tsetse of Glossina fuscipes fuscipes species in Ssugu parish of Mukono district, south-east Uganda were investigated. Tsetse caught with pyramidal traps were counted, sexed and dissected for age grading. It was observed that most tsetse were caught in valley habitats in the dry season, but the distribution was almost uniform within the parish in the wet season. The apparent density and prevalence of blood meals in tsetse fluctuated in different months. There were more males with a fresh blood meal than females (P < 0.05). In the population there was a preponderance of young tsetse of less than 60 days. There were significantly more teneral males than teneral females (P < 0.05). In all months the percentage of females was higher than that of males and ranged between 51.1% to 64.6 per cent. The epidemiological implications of these findings are that the risk of contracting trypanosomosis is high during the period of uniform distribution; since this is associated with an increase in apparent density and therefore high man-tsetse-animal contact. Furthermore, these results have shown that it is possible to prevent increase in the population of tsetse by applying insecticides on animals and targets in September and early October, since recruitment in tsetse population follows the rains.