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Vatcheva KP, Lee M, McCormick JB, Rahbar MH. The Effect of Ignoring Statistical Interactions in Regression Analyses Conducted in Epidemiologic Studies: An Example with Survival Analysis Using Cox Proportional Hazards Regression Model. ACTA ACUST UNITED AC 2015; 6. [PMID: 27347436 PMCID: PMC4918637 DOI: 10.4172/2161-1165.1000216] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To demonstrate the adverse impact of ignoring statistical interactions in regression models used in epidemiologic studies. STUDY DESIGN AND SETTING Based on different scenarios that involved known values for coefficient of the interaction term in Cox regression models we generated 1000 samples of size 600 each. The simulated samples and a real life data set from the Cameron County Hispanic Cohort were used to evaluate the effect of ignoring statistical interactions in these models. RESULTS Compared to correctly specified Cox regression models with interaction terms, misspecified models without interaction terms resulted in up to 8.95 fold bias in estimated regression coefficients. Whereas when data were generated from a perfect additive Cox proportional hazards regression model the inclusion of the interaction between the two covariates resulted in only 2% estimated bias in main effect regression coefficients estimates, but did not alter the main findings of no significant interactions. CONCLUSIONS When the effects are synergic, the failure to account for an interaction effect could lead to bias and misinterpretation of the results, and in some instances to incorrect policy decisions. Best practices in regression analysis must include identification of interactions, including for analysis of data from epidemiologic studies.
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Affiliation(s)
- K P Vatcheva
- Division of Epidemiology, University of Texas Health Science Center-Houston, School of Public Health, Brownsville Campus, Brownsville, TX, USA
| | - M Lee
- Division of Clinical and Translational Sciences, Department of Internal Medicine, Medical School; The University of Texas Health Science Center at Houston, Houston, TX, USA; Biostatistics/Epidemiology/Research Design (BERD) Core, Center for Clinical and Translational Sciences (CCTS), The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - J B McCormick
- Division of Epidemiology, University of Texas Health Science Center-Houston, School of Public Health, Brownsville Campus, Brownsville, TX, USA
| | - M H Rahbar
- Department of Epidemiology, Human Genetics, and Environmental Sciences (EHGES), University of Texas School of Public Health at Houston, Houston, TX, USA; Division of Clinical and Translational Sciences, Department of Internal Medicine, Medical School; The University of Texas Health Science Center at Houston, Houston, TX, USA; Biostatistics/Epidemiology/Research Design (BERD) Core, Center for Clinical and Translational Sciences (CCTS), The University of Texas Health Science Center at Houston, Houston, TX, USA
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Mittal MK, McCormick JB, Sposato LA, Grimaud O. Neighborhood socioeconomic status and stroke mortality: Disentangling individual and area effects. Neurology 2013; 81:938-9. [DOI: 10.1212/01.wnl.0000434339.51805.60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Qu HQ, Rentfro AR, Lu Y, Nair S, Hanis CL, McCormick JB, Fisher-Hoch SP. Host susceptibility to tuberculosis: insights from a longitudinal study of gene expression in diabetes. Int J Tuberc Lung Dis 2012; 16:370-2. [PMID: 22230325 DOI: 10.5588/ijtld.11.0536] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Tuberculosis (TB) remains a major global disease, and diabetes, which is documented to increase susceptibility to TB threefold, is also becoming pandemic. This susceptibility has been attracting extensive research interest. The increased risk of TB in diabetes may serve as a unique model to understand host susceptibility to specific pathogens in humans. To examine this rationale, we investigated the expression of reported TB candidate genes in a longitudinal diabetes study. Two genes, HK2 and CD28, emerged as potential culprits in diabetes-increased TB susceptibility.
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Affiliation(s)
- H-Q Qu
- Division of Epidemiology, Human Genetics and Environmental Sciences, University of Texas School of Public Health, Brownsville Regional Campus, Brownsville, Texas, USA.
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Abstract
OBJECTIVES To investigate life scientists' views of accountability and the ethical and societal implications of research. DESIGN Qualitative focus group and one-on-one interviews. PARTICIPANTS 45 Stanford University life scientists, including graduate students, postdoctoral fellows and faculty. RESULTS Two main themes were identified in participants' discussions of accountability: (1) the "how" of science and (2) the "why" of science. The "how" encompassed the internal conduct of research including attributes such as honesty and independence. The "why," or the motivation for conducting research, was two-tiered: first was the desire to positively impact the research community and science itself, and second was an interest in positively impacting the external community, broadly referred to as society. Participants noted that these motivations were influenced by the current systems of publications, grants and funding, thereby supporting a complex notion of boundary-setting between science and non-science. In addition, while all participants recognised the "how" of science and the two tiers of "why," scientists expressed the need to prioritise these domains of accountability. This prioritisation was related to a researcher's position in the academic career trajectory and to the researcher's subsequent "perceived proximity" to scientific or societal concerns. Our findings therefore suggest the need for institutional change to inculcate early-stage researchers with a broader awareness of the implications of their research. The peer review processes for funding and publication could be effective avenues for encouraging scientists to broaden their views of accountability to society.
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Affiliation(s)
- J M Ladd
- Center for Integration of Research on Genetics and Ethics, Stanford University, Palo Alto, CA, USA
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Kanabrocki EL, Sothern RB, Sackett-Lundeen L, Ryan MD, Johnson M, Foley S, Dawson S, Ocasio T, McCormick JB, Haus E, Kaplan E, Nemchausky B. Creatinine clearance and blood pressure: a 34-year circadian study. Clin Ter 2008; 159:409-417. [PMID: 19169600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND OBJECTIVE The first circadian study of the 361st Medical Laboratory, USAR, was conducted in May 1969 during the Annual Military Training at Brook Army Hospital, Fort Sam Houston, Texas. The study was approved by the Surgeon General, 5th US Army, and was designed to establish a circadian database for 63 medically relevant variables of 13 young members of the Unit. The subsequent studies, all in the month of May, in 1979, 1988, 1993,1998, and 2003, followed the same protocol and were conducted at Edward Hines Jr., Veterans Administration Hospital, after approval by Human Studies Subcommittees. Since a reduction in Creatinine Clearance (CrCl) to the level of 60 ml/min/1.73m2 signals the onset of kidney malfunction and since a concurrent increase in blood pressure (BP) >140/90 mm Hg, contributes greatly to an unfavorable cardiovascular prognosis, it seemed prudent to examine possible changes in these and in other relevant variables in a group of young Army men, which may have developed over a 34 year period of time. MATERIAL AND METHODS Thirteen US Army male volunteers (23-27y of age) served as subjects in the 1969 study. A majority of these men, two additional Army men and two non-military subjects, participated in subsequent studies: 1979 (7,2,1), 1988 (8,2,1), 1993 (5,4,1), 1998 (7,2,2), 2003 (7,2,1). In each study, subjects were admitted to a hospital ward, were given medical examination including a 12-lead electrocardiogram and followed the same Protocol. Lights "OUT" at 22:30h and "ON" at 06:30h. The meals, hospital 2400-calorie diets, were served at 17:30, 07:30 and at 13:30h. Vital signs were measured immediately after each 3h urine collections, around the clock, and bloods were collected every 3h. Blood, plasma, serum, saliva and urines were analyzed for numerous analytes including creatinine, using automated laboratory systems. Kidney functions were assessed using the measured and estimated glomerular filtration rates. RESULTS Over the 34y study span, 16 men provided sixty-one 24h profiles for CrCl-related variables (urine volume, creatinine, and serum creatinine) and fifty-eight profiles for BP. Using all normalized data, a significant circadian rhythm was found for each of these variables. Significant circadian variations in SBP, DBP, serum and urine creatinine, and urine volume, were evident with peak levels, on average, occurring in the evening hours. CONCLUSIONS In healthy subjects, age was associated with an increase in SBP and urine volume and with a decrease in urine creatinine. In diabetic subjects, aging was associated with increases in both blood pressure and Creatinine Clearance. It is interesting to note that for the 3 subjects who at a later date developed diabetes, the CrCl levels were higher than the 5 age-matched controls during each study year, over the entire 34y observation span, including the period prior to diagnosis. Clin Ter 2008; 159(6):409-417.
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Affiliation(s)
- E L Kanabrocki
- Nuclear Medicine, Edward Hines Jr, VA Hospital, Hines, IL 60141, USA.
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Kanabrocki EL, Ryan MD, Hermida RC, Ayala DE, McCormick JB, Dawson S, Lojo L, Hoffman HS, Siegel G, Friedman N, Eladasori B, Parachuri R, Nemchausky BA. Uric acid and renal function in multiple sclerosis. Clin Ter 2008; 159:35-40. [PMID: 18399261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVE The purpose of this study was to examine the circadian distribution of creatinine and uric acid clearances in subjects with Multiple Sclerosis. MATERIALS AND METHODS Eleven subjects with MS, 6 women (48+/-7y) and 5 men (58+/-5y) volunteered for this circadian study. Thirteen healthy females (39+/-11y) served as controls. Data of seven healthy male controls (64+/-8 y) were extracted from a similar circadian study conducted previously. Each MS patient, and each male control had blood samples drawn around the clock, at 3h intervals (8/24h), and each collected urines over 3h periods (8/24h). Each female control contributed only one blood sample and one complete 24h urine collection. Blood and urine samples were analyzed for a number of relevant analytes: ELAM, IL-6, NO, insulin, ACTH, aldosterone, cortisol, electrolytes, lymphocytes, monocytes including creatinine and uric acid clearances. Those were standardized to an average body surface area of 1.73 m2. RESULTS The relevant analytes demonstrated increased synthesis of insulin, IL-6, ELAM, monocytes, and reduced concentrations of serum NO. The creatinine clearances were significantly lower in MS females than in female controls, 63+/-22 vs.108+/-18 ml/min. They were also lower than those of MS males and male controls, 107.8+/-17, 97.5+/-8.2 ml/min. Uric acid clearances in MS females were also lower 6.9+/-2.4 vs. 10.5+/-4.4 ml/min. The uric acid clearance in MS males was higher than in male controls, 7.0+/-4.5 vs. 4.0+/-1.0 ml/min. CONCLUSIONS The alterations in selected relevant analytes and the reduced creatinine and uric acid clearances in females but not in males, suggest a renal dysfunction in MS females. These observations may contribute to understanding better the mechanism of renal dysfunction in female patients and perhaps this may be an additional factor contributing to greater frequency of MS in females than in male subjects.
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Affiliation(s)
- E L Kanabrocki
- Nuclear Medicine Service, Edward Hines Jr., VA Hospital, Hines, IL 60141, USA.
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Kanabrocki EL, Vesely DL, Hermida RC, Ayala DE, Ryan MD, Burden J, Shah F, Friedman NC, Eladasari B, Nemchausky BA, Dawson S, McCormick JB, Alessandrini SM, Hooper DC. Circadian distribution of hematology variables in subjects with multiple sclerosis. Clin Ter 2006; 157:241-7. [PMID: 16900851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hematology variables were measured in blood samples obtained every 3h (8/24h) from 10 multiple sclerosis (MS) patients and 34 healthy subjects and analyzed for circadian characteristics using the population multiple-components method. Red blood cell (RBC) and hemoglobin levels as well as hematocrits exhibited circadian rhythms with minimal amplitudes in healthy individuals and insignificant variability in the smaller group of MS patients. In contrast the total white blood cell (WBC) and platelet counts for MS patients and healthy individuals both showed significant circadian characteristics while the mean 24h WBC and platelet levels did not significantly differ between the two groups. When the different WBC subsets were examined independently, statistically significant circadian rhythms were seen for lymphocytes and eosinophils for both MS patients and healthy individuals and for neutrophils only in the latter. Moreover, the 24h mean levels of lymphocytes, basophils, and eosinophils were significantly higher for the healthy controls while those of monocytes were higher for the MS patients. However, of all the variables tested with significant circadian rhythms in both groups of individuals, only those of lymphocyte numbers exhibited different patterns with somewhat higher amplitude in healthy individuals and a peak level occurring over an hour after that of MS patients. These changes may be the reflection of a disturbance in the regulation of patterns of lymphocyte activity and migration in MS patients. In addition, the elevation in circulating monocytes in MS patients is consistent with the inflammatory nature of the disease.
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Affiliation(s)
- E L Kanabrocki
- Department Nuclear Medicine, University of South Florida, Tampa, FL, USA.
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Third JLHC, Ryan MD, Sothern RB, Dawson S, McCormick JB, Hoffman HS, Gathing A, Jankowski RA, Kania KS, Kanabrocki EL. Circadian distribution of iron and ferritin in serum of healthy and type 2 diabetic males. Clin Ter 2006; 157:35-40. [PMID: 16669550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
AIM We examined the circulating levels of iron and ferritin in serum of seven healthy and three insulin non-dependent diabetic (Type 2) males in order to compare their circadian characteristics. METHODS Blood samples were collected every 3h over a 24h period and were analyzed for serum iron and ferritin. RESULTS The mean Fe level was significantly higher in healthy than in diabetic subjects: 80.0 +/- 3.3 vs. 63.0 +/- 3.7 microg/dL. The ferritin level was significantly lower in healthy than in diabetic men: 79.8 +/- 4.7 vs. 186.3 +/- 110.5 microg/L. A significant (p < 0.001) time-effect was found by ANOVA and circadian rhythm was detected at p < 0.001 in all data sets when a 24h cosine was fitted to the normalized data. Acrophases were located in mid to late morning for Fe (11:30, vs. 09:22h) and for ferritin (11:10 vs. 11:46h). DISCUSSION We concluded that there is significant circadian variation in both serum Fe and ferritin, with predictable peaks in the mid to late morning.
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Affiliation(s)
- J L H C Third
- Cardiology Laboratory, Edward Hines, Jr Veterans Medical Center, Hines, IL 60141, USA
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Abstract
UNLABELLED PspA and PsaA are Streptococcus pneumoniae surface proteins and potential pneumococcal vaccine antigens. The aim of this study was to characterize the transplacental transfer of antibodies to PspA and to PsaA. Paired mother and cord blood sera were obtained at delivery from 28 women. Concentrations of antibodies against PspA, PsaA, tetanus toxoid (vaccine-induced antibodies) and P6-outer membrane protein (OMP) of nontypeable Haemophilus influenzae were determined by ELISA. Antibodies to PspA of the IgG, IgG1 and IgG2 antibodies were also determined. The geometric mean percentage (GM%) of the paired infant:mother antibody were calculated. RESULTS The GM% of the infant:mother antibody concentrations against PspA, PsaA and P6-OMP antibodies were 64.7% (3.3 micro g/ml in infants vs. 5.1 micro g/ml in mothers), 50.4% (6.8 micro g/ml vs. 13.5 micro g/ml) and 66.7% (5.6 micro g/ml vs. 8.4 micro g/ml), respectively; the GM% of antibodies against tetanus toxoid was 104.5% (4.6 micro g/ml vs. 4.4 micro g/ml). Transplacental transfer of IgG1 was more efficient than that of IgG2 (approximately 120%vs. 65%). A transplacental transfer of antibodies to PspA and to PsaA exist. Moreover, these data suggest an active placental transfer of IgG1 antibodies to PspA since the concentration of these antibodies were consistently higher in cord sera than in the mother's sera.
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Affiliation(s)
- L Baril
- Aventis Pasteur, Lyon, France.
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Affiliation(s)
- J B McCormick
- University of Texas, School of Public Health, Brownsville, TX, USA
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Abstract
Arenaviruses, such as Lassa fever, establish chronic infections in rodents, leading to incidental transmission to humans. Lassa fever is a clinically severe disease, yet the absence of second attacks implies life-long immunity. The aim of this review is to consider whether such immunity could be provided by vaccines. The South American arenaviruses are controlled by neutralising antibody and a clinical trial of live, attenuated vaccine for Argentinian haemorrhagic fever provided 84% protection. In contrast, there is no evidence for protective humoral immunity against Old World arenaviruses which are controlled by cell-mediated immune responses. Nevertheless, vaccination with Lassa glycoproteins can protect monkeys from disease, implying that protection may be achievable, even though the immunological mechanisms are distinct. Recombinant vaccinia viruses expressing various forms of Lassa glycoproteins can protect both guinea-pigs and primates, while additional protective responses can be mounted against nucleocapsid genes. However, vaccines based upon vaccinia constructs are no longer tenable for African populations with a high seroprevalence of HIV infection. The scientific challenge now remains to find alternative methods of delivering T-cell immunity against glycoproteins from Lassa virus in ways which can overcome the local economic and political hurdles to vaccine development.
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Affiliation(s)
- S P Fisher-Hoch
- University of Texas School of Public Health at Brownsville, 80 Fort Brown, SET. B 1.334, Brownsville, Texas 78520, USA.
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Shah SM, Luby S, Rahbar M, Khan AW, McCormick JB. Hypertension and its determinants among adults in high mountain villages of the Northern Areas of Pakistan. J Hum Hypertens 2001; 15:107-12. [PMID: 11317189 DOI: 10.1038/sj.jhh.1001131] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2000] [Revised: 07/07/2000] [Accepted: 07/21/2000] [Indexed: 11/08/2022]
Abstract
We studied the prevalence and determinants of hypertension among adults in mountainous rural villages in the Ghizar district Northern Areas of Pakistan, an area that recently has undergone substantial economic development. We selected a stratified random sample of 4203 adults (age > 18 years) from 16 villages in Punial Valley of Ghizar district where the number of study subjects from each village was proportionate to the size of the village. We obtained blood pressure (BP) records by taking the mean of the second and third BP measurement, using a standard mercury sphygmomanometer, and assessed risk factors for hypertension in the study subjects. The mean +/- s.d. blood pressures (mm Hg) were 125 +/- 19 systolic and 80 +/- 12 diastolic in men and 125 +/- 22 systolic and 78 +/- 14 diastolic in women. The 125 +/- 22 systolic and 78 +/- 14 diastolic in women. The mm Hg, or systolic BP > or = 140 mm Hg or currently taking antihypertensive medication) was 15%, increasing from 4% in the 18-29 year age group to 36% among persons 60 years of age or older. The age-standardised prevalence of hypertension was 14% (12.5% among men and 14% among women). There was no significant difference in prevalence of hypertension in males, and in females. Multivariate analysis revealed that age, and higher body mass index (overweight and obesity) were independently associated with higher prevalence of hypertension. People with hypertension were more likely to have a first-degree relative with physician-diagnosed hypertension (OR = 1.90, 95% CI 1.49, 2). Hypertension is a significant health problem in rural northern Pakistan. The primary health care programme in the Northern Areas of Pakistan needs to address this problem, especially identifying people at risk.
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Affiliation(s)
- S M Shah
- Department of Community Health Sciences, The Aga Khan University, Karachi, Pakistan.
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Abstract
Lassa fever has been estimated to cause 5,000 deaths annually in West Africa. Recently, war in the zone where Lassa fever is hyperendemic has severely impeded control and treatment. Vaccination is the most viable control measure. There is no correlation between antibody levels and outcome in human patients, and inactivated vaccines produce high titers of antibodies to all viral proteins but do not prevent virus replication and death in nonhuman primates. Accordingly, we vaccinated 44 macaques with vaccinia virus-expressed Lassa virus structural proteins separately and in combination, with the object of inducing a predominantly TH1-type immune response. Following Lassa virus challenge, all unvaccinated animals died (0% survival). Nine of 10 animals vaccinated with all proteins survived (90% survival). Although no animals that received full-length glycoprotein alone had a high titer of antibody, 17 of 19 survived challenge (88%). In contrast, all animals vaccinated with nucleoprotein developed high titers of antibody but 12 of 15 died (20% survival). All animals vaccinated with single glycoproteins, G1 or G2, died, but all those that received both single glycoproteins (G1 plus G2) at separate sites survived, showing that both glycoproteins are independently important in protection. Neither group had demonstrable antibody levels prior to challenge. We demonstrate that in primates, immune responses to epitopes on both glycoproteins are required to protect against lethal challenge with Lassa virus without having untoward side effects and that this protection is likely to be primarily cell mediated. We show that an effective, safe vaccine against Lassa virus can and should be made and that its evaluation for human populations is a matter of humanitarian priority.
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Affiliation(s)
- S P Fisher-Hoch
- Special Pathogens Branch, Division of Viral, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Leroy EM, Baize S, Volchkov VE, Fisher-Hoch SP, Georges-Courbot MC, Lansoud-Soukate J, Capron M, Debré P, McCormick JB, Georges AJ. Human asymptomatic Ebola infection and strong inflammatory response. Lancet 2000; 355:2210-5. [PMID: 10881895 DOI: 10.1016/s0140-6736(00)02405-3] [Citation(s) in RCA: 326] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ebola virus is one of the most virulent pathogens, killing a very high proportion of patients within 5-7 days. Two outbreaks of fulminating haemorrhagic fever occurred in northern Gabon in 1996, with a 70% case-fatality rate. During both outbreaks we identified some individuals in direct contact with sick patients who never developed symptoms. We aimed to determine whether these individuals were indeed infected with Ebola virus, and how they maintained asymptomatic status. METHODS Blood was collected from 24 close contacts of symptomatic patients. These asymptomatic individuals were sampled 2, 3, or 4 times during a 1-month period after the first exposure to symptomatic patients. Serum samples were analysed for the presence of Ebola antigens, virus-specific IgM and IgG (by ELISA and western blot), and different cytokines and chemokines. RNA was extracted from peripheral blood mononuclear cells, and reverse transcriptase-PCR assays were done to amplify RNA of Ebola virus. PCR products were then sequenced. FINDINGS 11 of 24 asymptomatic individuals developed both IgM and IgG responses to Ebola antigens, indicating viral infection. Western-blot analysis showed that IgG responses were directed to nucleoprotein and viral protein of 40 kDa. The glycoprotein and viral protein of 24 kDa genes showed no nucleotide differences between symptomatic and asymptomatic individuals. Asymptomatic individuals had a strong inflammatory response characterised by high circulating concentrations of cytokines and chemokines. INTERPRETATION This study showed that asymptomatic, replicative Ebola infection can and does occur in human beings. The lack of genetic differences between symptomatic and asymptomatic individuals suggest that asymptomatic Ebola infection did not result from viral mutations. Elucidation of the factors related to the genesis of the strong inflammatory response occurring early during the infectious process in these asymptomatic individuals could increase our understanding of the disease.
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Affiliation(s)
- E M Leroy
- Centre International de Recherches Médicales de Franceville, Gabon.
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Kanabrocki EL, Third JL, Ryan MD, Nemchausky BA, Shirazi P, Scheving LE, McCormick JB, Hermida RC, Bremner WF, Hoppensteadt DA, Fareed J, Olwin JH. Circadian relationship of serum uric acid and nitric oxide. JAMA 2000; 283:2240-1. [PMID: 10807381 DOI: 10.1001/jama.283.17.2240] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Leroy EM, Baize S, Lu CY, McCormick JB, Georges AJ, Georges-Courbot MC, Lansoud-Soukate J, Fisher-Hoch SP. Diagnosis of Ebola haemorrhagic fever by RT-PCR in an epidemic setting. J Med Virol 2000; 60:463-7. [PMID: 10686031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
This study reports the first field evaluation of a new diagnostic technique for Ebola virus disease with sensitivity and specificity. Ebola virus causes rare but fulminating outbreaks in Equatorial Africa. Rapid differentiation from other infections is critical for timely implementation of public health measures. Patients usually die before developing antibodies, necessitating rapid virus detection. A reverse transcriptase-polymerase chain reaction (RT-PCR) assay was developed, implemented and evaluated at Centre International de Recherches Médicales de Franceville (CIRMF) in Gabon, to detect Ebola viral RNA in peripheral blood mononuclear cells (PBMC). Twenty-six laboratory-confirmed patients during and 5 after the acute phase of Ebola haemorrhagic fever, 15 healthy controls and 20 febrile patients not infected with Ebola virus were studied. RT-PCR results were compared with ELISA antigen capture, and Ebola specific IgM and IgG antibody detection. Ebola virus RNA was amplified from 26/26 specimens from the acute phase, 3/5 during recovery, 0/20 febrile patients and 1/15 negative controls. Sensitivity of RT-PCR in identifying acute infection and early convalescence compared with antigen or IgM detection was 100% and 91% respectively, and specificity compared with antigen detection and IgM assay combined was 97%. Antigen capture detected only 83% of those identified by PCR, and IgM only 67%. Ebola virus RNA was detected in all 13 fatalities, only 5 of whom had IgM and none IgG. RT-PCR detected Ebola RNA in PBMC one to three weeks after disappearance of symptoms when antigen was undetectable. RT-PCR was the most sensitive method and able to detect virus from early acute disease throughout early recovery.
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Affiliation(s)
- E M Leroy
- Centre International de Recherches Médicales de Franceville, BP 769 Franceville, Gabon.
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Abstract
In 1977, Price and Greenberg identified the tetrapeptide FMRFamide as a cardioexcitatory molecule from mollusc. Subsequent to this discovery, FMRFamide-related peptides (FaRPs) have been identified in both invertebrates and vertebrates. Peptides in the FaRP family contain a common RFamide C-terminus and act as modulators and messengers of neural and gastrointestinal functions. Like other organisms, Drosophila melanogaster contains several genes that encode for numerous FaRPs. Elucidating the processing and activities of multiple FaRPs encoded in a single precursor is critical to establishing their roles in physiology. In this manuscript, we describe the distribution of FMRFamide immunoreactive materials in the Drosophila central nervous system and gut, and correlate it with the expression of specific FaRPs and their activities. The unique distributions and biological activities of Drosophila FaRPs suggest that the precursors are highly processed and the structurally related peptides are not functionally redundant. The complete distribution of FaRPs in the central nervous system and gut as detected by FMRFamide antisera is not accounted for by the sum of the individual expression patterns of the known Drosophila peptides. Thus, these data suggest that one or more Drosophila FaRPs or structurally related peptides remain to be discovered.
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Affiliation(s)
- R Nichols
- Biological Chemistry Department, University of Michigan, Ann Arbor 48109-1048, USA.
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Bremner WF, Sothern RB, Kanabrocki EL, Ryan M, McCormick JB, Dawson S, Connors ES, Rothschild R, Third JL, Vahed S, Nemchausky BM, Shirazi P, Olwin JH. Relation between circadian patterns in levels of circulating lipoprotein(a), fibrinogen, platelets, and related lipid variables in men. Am Heart J 2000; 139:164-73. [PMID: 10618578 DOI: 10.1016/s0002-8703(00)90324-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND A correlation has been reported between lipoprotein(a) [Lp(a)] concentration and risk for coronary artery disease. High concentrations of Lp(a) might be markers for vascular or tissue injury or might be associated with other genetic or environmental factors that can cause acute myocardial infarction. METHODS We measured the circadian characteristics of circulating Lp(a), fibrinogen, platelets, cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol for a group of adult male volunteers who had no clinical symptoms. We obtained samples every 3 hours around the clock to assess the normal degree of variation within a 24-hour period and to test for similarities in circadian patterns and correlations with level of Lp(a). RESULTS Each variable displayed a highly significant circadian rhythm. Lp(a), fibrinogen, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol peaked in the morning. Cholesterol and platelets peaked in the late afternoon, and triglycerides peaked in the evening. CONCLUSIONS Although peak levels of Lp(a) and fibrinogen coincide with reported morning peak frequencies of myocardial infarction and stroke, the platelet peak appears to coincide with late afternoon peak frequencies of sudden cardiac death and fatal stroke. The data suggest that proper timing of single samples may improve the usefulness and accuracy of diagnosis, risk assessment, and therapy.
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Affiliation(s)
- W F Bremner
- MacNeal Cardiology Group, Berwyn, IL 60402, USA
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19
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Khan AJ, Luby SP, Fikree F, Karim A, Obaid S, Dellawala S, Mirza S, Malik T, Fisher-Hoch S, McCormick JB. Unsafe injections and the transmission of hepatitis B and C in a periurban community in Pakistan. Bull World Health Organ 2000; 78:956-63. [PMID: 10994278 PMCID: PMC2560828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Following reports of frequent deaths associated with jaundice and chronic liver disease among adults in a periurban community of Karachi, Pakistan, an investigation was conducted to evaluate the relationship between injections and viral hepatitis infections, to identify the reasons why patients received frequent injections, and to observe the injection practices employed in clinics. Two hundred and three adult patients were interviewed as they left each of the 18 area clinics. Practitioners were interviewed and three consecutive injections were observed at each clinic. Eighty-one per cent of patients received an injection on the day of the interview. Of the 135 patients who provided a serum sample, 59 (44%) had antibodies against hepatitis C virus and 26 (19%) had antibodies against hepatitis B virus. Patients who received more injections were more likely to be infected with hepatitis C. If oral and injected medications were equally effective, 44% of patients preferred injected medication. None of the practitioners knew that hepatitis C could be transmitted by injections. Non-sterile syringes and needles that had been used earlier in the day on other patients were used for 94% of the observed injections. Interventions to limit injections to those which are safe and clinically indicated are needed to prevent injection-associated infections in Pakistan and other low-income countries.
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Affiliation(s)
- A J Khan
- Community Health Sciences Department, Aga Khan University, Karachi, Pakistan
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20
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Pasha O, Luby SP, Khan AJ, Shah SA, McCormick JB, Fisher-Hoch SP. Household members of hepatitis C virus-infected people in Hafizabad, Pakistan: infection by injections from health care providers. Epidemiol Infect 1999; 123:515-8. [PMID: 10694166 PMCID: PMC2810789 DOI: 10.1017/s0950268899002770] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Household members of people with hepatitis C are at increased risk of HCV infection. The prevalence and routes of transmission of HCV to household members in Hafizabad, Pakistan were investigated. Household members of 24 index cases were given a risk factor questionnaire, tested for HCV infection, and the risk factors between the infected and uninfected were compared. Twelve of 74 household members (16.2%) were seropositive for HCV antibody. This was 2(1/2) times the rate of infection in the general population (OR = 2.8; P = 0.01). None of the routes of transmission studied within the household was associated with an increased risk. Household members who received more than 4 injections per year were 11.9 times more likely to be infected than those who had not (P = 0.016). In Hafizabad, the greatest risk for HCV infection to household members of infected people is injections given by health-care workers rather than household contact with infected persons.
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Affiliation(s)
- O Pasha
- Department of Community Health Sciences, The Aga Khan University Medical College, Karachi, Pakistan
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21
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Besson C, Pialoux G, Dupont B, Pol S, Hermine O, Arnulf B, Landau A, McCormick JB. Lack of association between HCV infection and HIV-related lymphoma. Br J Haematol 1999; 105:568-9. [PMID: 10233441 DOI: 10.1111/j.1365-2141.1999.01419.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Bloland PB, Ruebush TK, McCormick JB, Ayisi J, Boriga DA, Oloo AJ, Beach R, Hawley W, Lal A, Nahlen B, Udhayakumar V, Campbell CC. Longitudinal cohort study of the epidemiology of malaria infections in an area of intense malaria transmission I. Description of study site, general methodology, and study population. Am J Trop Med Hyg 1999; 60:635-40. [PMID: 10348240 DOI: 10.4269/ajtmh.1999.60.635] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A large-scale longitudinal cohort project was initiated in western Kenya in June 1992. The primary purpose of the project was to study Plasmodium falciparum malaria in a highly endemic area using a comprehensive and multidisciplinary approach, which included epidemiology, entomology, and immunology. Between June 1992 and July 1994, pregnant women living in 15 rural villages were identified during a monthly census and 1,164 were enrolled. The women were followed-up throughout their pregnancy and they, along with their newborn infants and direct siblings of the infants' less than 15 years of age, were monitored over time. As of May 1995, 1,017 infants had been born to these women. This paper presents the design and general methodology used in this study and describes the initial experience with intense monitoring of a large population over a prolonged period.
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Affiliation(s)
- P B Bloland
- Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3724, USA
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23
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Baize S, Leroy EM, Georges-Courbot MC, Capron M, Lansoud-Soukate J, Debré P, Fisher-Hoch SP, McCormick JB, Georges AJ. Defective humoral responses and extensive intravascular apoptosis are associated with fatal outcome in Ebola virus-infected patients. Nat Med 1999; 5:423-6. [PMID: 10202932 DOI: 10.1038/7422] [Citation(s) in RCA: 400] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ebola virus is very pathogenic in humans. It induces an acute hemorrhagic fever that leads to death in about 70% of patients. We compared the immune responses of patients who died from Ebola virus disease with those who survived during two large outbreaks in 1996 in Gabon. In survivors, early and increasing levels of IgG, directed mainly against the nucleoprotein and the 40-kDa viral protein, were followed by clearance of circulating viral antigen and activation of cytotoxic T cells, which was indicated by the upregulation of FasL, perforin, CD28 and gamma interferon mRNA in peripheral blood mononuclear cells. In contrast, fatal infection was characterized by impaired humoral responses, with absent specific IgG and barely detectable IgM. Early activation of T cells, indicated by mRNA patterns in peripheral blood mononuclear cells and considerable release of gamma interferon in plasma, was followed in the days preceding death by the disappearance of T cell-related mRNA (including CD3 and CD8). DNA fragmentation in blood leukocytes and release of 41/7 nuclear matrix protein in plasma indicated that massive intravascular apoptosis proceeded relentlessly during the last 5 days of life. Thus, events very early in Ebola virus infection determine the control of viral replication and recovery or catastrophic illness and death.
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Affiliation(s)
- S Baize
- Centre International de Recherches Médicales de Franceville, Gabon.
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24
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Bloland PB, Boriga DA, Ruebush TK, McCormick JB, Roberts JM, Oloo AJ, Hawley W, Lal A, Nahlen B, Campbell CC. Longitudinal cohort study of the epidemiology of malaria infections in an area of intense malaria transmission II. Descriptive epidemiology of malaria infection and disease among children. Am J Trop Med Hyg 1999; 60:641-8. [PMID: 10348241 DOI: 10.4269/ajtmh.1999.60.641] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A large-scale longitudinal cohort project was initiated in western Kenya in June 1992. Between June 1992 and July 1994, 1,848 children less than 15 years of age were monitored prospectively for a mean of 236 days. During this period, 12,035 blood smears were examined for malaria and only 34% were found to be negative. Parasite prevalence (all species) decreased with age (from a high of 83% among children 1-4 years old to 60% among children 10-14 years old). Even more dramatic decreases were noted in the prevalence of high density falciparum infection (from 37% among children 12-23 months old to < 1% among 10-14-year-old children) and in clinical malaria (20% to 0.3% in the same age groups). Children < 1 year of age accounted for 55% of all cases of anemia detected. Anemia was consistently associated with high density infection in children < 10 years of age (20% to 210% increased risk relative to aparasitemic children). These results demonstrate the relationship between high-density malaria infection and two clinical manifestations of malarial illness.
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Affiliation(s)
- P B Bloland
- Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3724, USA
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Jezek Z, Szczeniowski MY, Muyembe-Tamfum JJ, McCormick JB, Heymann DL. Ebola between outbreaks: intensified Ebola hemorrhagic fever surveillance in the Democratic Republic of the Congo, 1981-1985. J Infect Dis 1999; 179 Suppl 1:S60-4. [PMID: 9988166 DOI: 10.1086/514295] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Surveillance for Ebola hemorrhagic fever was conducted in the Democratic Republic of the Congo from 1981 to 1985 to estimate the incidence of human infection. Persons who met the criteria of one of three different case definitions were clinically evaluated, and blood was obtained for antibody confirmation by IFA. Contacts of each case and 4 age- and sex-matched controls were also clinically examined and tested for immunofluorescent antibody. Twenty-one cases of Ebola infection (persons with an antibody titer of > or = 1:64, or lower if they fit the clinical case definition) were identified, with a maximum 1-year incidence of 9 and a case fatality rate of 43%. Cases occurred throughout the year, but most (48%) occurred early in the rainy season. Fifteen percent of contacts had antibody titers > or =1:64 to Ebola virus, compared with 1% of controls (P < .0001). Results suggest that Ebola virus periodically emerges from nature to infect humans, that person-to-person transmission is relatively limited, and that amplification to large epidemics is unusual.
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Affiliation(s)
- Z Jezek
- World Health Organization, Geneva, Switzerland
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26
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Kanabrocki EL, Sothern RB, Messmore HL, Roitman-Johnson B, McCormick JB, Dawson S, Bremner FW, Third JL, Nemchausky BA, Shirazi P, Scheving LE. Circadian interrelationships among levels of plasma fibrinogen, blood platelets, and serum interleukin-6. Clin Appl Thromb Hemost 1999; 5:37-42. [PMID: 10725981 DOI: 10.1177/107602969900500108] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Circadian (24 h) rhythms of fibrinogen, interleukin-6 (IL-6), and platelet levels were studied in 11 males ages 46 to 72 years. Since there is a known circadian rhythm for fibrinogen and IL-6, we postulated that the peak level (acrophase) of fibrinogen would follow the acrophase of IL-6, based on the fact that IL-6 is the stimulus for fibrinogen production in the liver. Platelet levels were measured to show whether there was any correlation with the IL-6 acrophase because it has been reported that IL-6 affects megakaryocytes and platelets in dogs. We found that the acrophase for IL-6 occurred at 02:03 h and the acrophase for fibrinogen occurred at 09:16 h. Platelet counts peaked at 16:56 h. Thus, there was a positive correlation between IL-6 and fibrinogen acrophases and a negative correlation of each with the acrophase for platelets. The positive linkage of IL-6 with fibrinogen in this study suggests that suppression of IL-6 production would lower those peak fibrinogen levels that occur in the morning in association with arterial ischemic events. This could result in fewer arterial ischemic events, especially in the morning.
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Affiliation(s)
- E L Kanabrocki
- Department of Nuclear Medicine Service, Veterans Affairs Hospital, Hines, Illinois 60141, USA
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28
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Baqi S, Nabi N, Hasan SN, Khan AJ, Pasha O, Kayani N, Haque RA, Khurshid M, Fisher-Hoch S, Luby SP, McCormick JB. HIV antibody seroprevalence and associated risk factors in sex workers, drug users, and prisoners in Sindh, Pakistan. J Acquir Immune Defic Syndr Hum Retrovirol 1998; 18:73-9. [PMID: 9593461 DOI: 10.1097/00042560-199805010-00011] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To determine prevalence of HIV infection and risk behaviors in commercial sex workers (CSWs), drug users, and prisoners in Sindh, Pakistan. METHODS A medical clinic was established in a "red-light" district of Karachi. Eighty-one CSWs who registered at the clinic between November 1993 and June 1994 were provided HIV counseling and testing and administered a risk factor questionnaire. Next, 316 male drug users were tested for HIV-1 antibody from April to July 1994. Finally, a voluntary serosurvey of HIV-1 and HIV-2 and risk behaviors of 3525 prisoners in Sindh was conducted between July 1994 and December 1994. Abbott Recombinant HIV third-generation enzyme-linked immunosorbent assay (ELISA) and confirmatory testing with Western blot analysis were used in all three groups. RESULTS None of 81 CSWs tested for HIV-1 antibody were positive. None of 316 drug users tested positive for HIV-1 antibody. Of 3441 male prisoners, 1 was HIV-1 infected, and of 84 female prisoners, 1 was HIV-1 infected. No prisoner was positive for HIV-2 antibody. DISCUSSION The prevalence of HIV in CSWs, drug users, and prisoners in Sindh is low at present. Intervention programs implemented at this stage can make an impact in HIV prevention.
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Affiliation(s)
- S Baqi
- Department of Community Health Sciences, Aga Khan University Hospital, Karachi, Pakistan.
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29
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Luby SP, Faizan MK, Fisher-Hoch SP, Syed A, Mintz ED, Bhutta ZA, McCormick JB. Risk factors for typhoid fever in an endemic setting, Karachi, Pakistan. Epidemiol Infect 1998; 120:129-38. [PMID: 9593481 PMCID: PMC2809381 DOI: 10.1017/s0950268897008558] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We conducted a study to evaluate risk factors for developing typhoid fever in a setting where the disease is endemic in Karachi, Pakistan. We enrolled 100 cases with blood culture-confirmed Salmonella typhi between July and October 1994 and 200 age-matched neighbourhood controls. Cases had a median age of 5.8 years. In a conditional logistic regression model, eating ice cream (Odds ratio [OR] = 2.3; 95% confidence interval [CI] 1.2-4.2, attributable risk [AR] = 36%), eating food from a roadside cabin during the summer months (OR = 4.6, 95% CI 1.6-13.0; AR = 18%), taking antimicrobials in the 2 weeks preceding the onset of symptoms (OR = 5.7, 95% CI 2.3-13.9, AR = 21%), and drinking water at the work-site (OR = 44.0, 95% CI 2.8-680, AR = 8%) were all independently associated with typhoid fever. There was no difference in the microbiological water quality of home drinking water between cases and controls. Typhoid fever in Karachi resulted from high-dose exposures from multiple sources with individual susceptibility increased by young age and prior antimicrobial use. Improving commercial food hygiene and decreasing unnecessary antimicrobial use would be expected to decrease the burden of typhoid fever.
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Affiliation(s)
- S P Luby
- Community Health Sciences Department, Aga Khan University, Karachi, Pakistan
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Abstract
The rapid global expansion of bacteria resistant to antimicrobials is the most important development over the past year in emerging bacterial diseases. The critical events are the emergence of Staphylococcus aureus with decreased sensitivity to vancomycin, worldwide resistance to penicillin in Streptococcus pneumoniae, and the remorseless progression of multiply-resistant Mycobacterium tuberculosis. Most startling was the isolation from a human in Madagascar of a plague bacillus possessing a plasmid readily transferable to Escherichia coli, which confers multiple antibiotic resistance. The hospital environment continues to see the transmission of resistant organisms, notably vancomycin-resistant enterococci. Finally, as food markets become more open around the world, food-borne outbreaks of E. coli O157 and cholera demonstrate how difficult it can be to establish effective health and safety barriers.
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Affiliation(s)
- J B McCormick
- Institut Pasteur, 28 Rue du Dr Roux, F-75724 Paris Cedex 15, France.
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31
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Luby SP, Qamruddin K, Shah AA, Omair A, Pahsa O, Khan AJ, McCormick JB, Hoodbhouy F, Fisher-Hoch S. The relationship between therapeutic injections and high prevalence of hepatitis C infection in Hafizabad, Pakistan. Epidemiol Infect 1997; 119:349-56. [PMID: 9440439 PMCID: PMC2809008 DOI: 10.1017/s0950268897007899] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
To determine the prevalence and routes of transmission of hepatitis C virus (HCV) infection in Hafizabad, Pakistan, we collected sera in 1993 from a geographically based random sample of residents, and in 1994 identified 15 HCV-infected individuals (cases) and 67 age and sex matched uninfected individuals (controls). Initially we approached 504 households, and collected serum from a randomly selected household member in 309 (64%). Twenty persons (6.5%) had anti-HCV antibody; 31% percent had hepatitis B core antibodies, and 4.3% had hepatitis B surface antigen. In the case-control study, persons who received more therapeutic injections (categorized as averaging 1, 2-4, 5-9 or > 10 injections per year in the previous 10 years) were more likely to be infected with HCV (odds ratio 0, 1.5, 2.5 and 6.9 respectively, P = 0.008) compared to persons averaging 0 injections per year. Efforts to limit therapeutic injections to only those that are medically indicated and that use sterile equipment are essential in order to prevent transmission of HCV.
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Affiliation(s)
- S P Luby
- Community Health Sciences Department, Aga Khan University, Karachi, Pakistan
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Lasee A, McCormick JB. Demographic and socio-economic determinants of contraceptive use in a low income community of Karachi. J PAK MED ASSOC 1996; 46:228-31. [PMID: 8961708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The study objectives were to assess multiple factors associated with the use of contraceptives among married women living in a low income community in Karachi. The study was a cross sectional survey of 608 women between the ages of 15 and 49 years. The mean number of living children per woman was 3.7 (confidence intervals 3.49-3.9). The literacy rate was 53%. The current use of contraceptives was 29%. Among many variables examined and in consistence with studies in other countries, women were 4 to 5 times more likely to use contraceptives if they had 3 or more living children than if they had two or fewer living children (p = .000). These results strongly suggest that the number of surviving children and women's education are key determinants in decision-making about contraceptive use and as such are intervention points to increase contraceptive use. Stronger policies focused on improving child survival, reducing the perceived ideal family size through increased female education will be more likely to reduce fertility.
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Affiliation(s)
- A Lasee
- Department of Community Health Sciences, Aga Khan University, Karachi
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34
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Vesely DL, Sothern RB, Scheving LE, Bremner FW, Third JL, McCormick JB, Dawson S, Kahn S, Augustine G, Ryan M, Greco J, Nemchausky BA, Shirazi P, Kanabrocki EL. Circadian relationships between circulating atrial natriuretic peptides and serum calcium and phosphate in healthy humans. Metabolism 1996; 45:1021-8. [PMID: 8769363 DOI: 10.1016/s0026-0495(96)90274-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Long-acting natriuretic peptide (LANP), vessel dilator (VSDL), and atrial natriuretic factor (ANF) consisting of amino acids (aa) 1 to 30, 31 to 67, and 99 to 126, respectively, of the 126-aa ANF prohormone circulate in humans. Among the biologic properties of these peptides is the ability of ANF to decrease intracellular calcium concentrations. To determine if atrial natriuretic peptides are directly related to serum calcium and/or phosphate in healthy normocalcemic humans, we examined 21 24-hour profiles of VSDL, LANP, ANF, and serum calcium and phosphate in 14 healthy humans. VSDL, LANP, and ANF each had significant (P < .001) circadian rhythms, with peak concentrations late during sleep (at 4:00 AM) being nearly twice the concentrations in the afternoon and evening. Serum calcium and phosphate also had significant circadian rhythms (P < .001) with troughs nearly opposite to those of the atrial natriuretic peptides, suggesting that atrial peptides may be important in the modulation of the circadian rhythms of calcium and phosphate. The nearly identical circadian rhythms of the atrial natriuretic peptides and of parathyroid hormone (PTH) reported by others, along with evidence that PTH may increase atrial peptide release, suggest that some of the effects attributed to PTH may be mediated by atrial natriuretic peptides.
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Affiliation(s)
- D L Vesely
- Department of Internal Medicine, University of South Florida Health Sciences Center, Tampa, USA
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35
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Sothern RB, Vesely DL, Kanabrocki EL, Bremner FW, Third JL, McCormick JB, Dawson S, Ryan M, Greco J, Bean JT, Nemchausky BM, Shirazi P, Scheving LE. Circadian relationships between circulating atrial natriuretic peptides and serum sodium and chloride in healthy humans. Am J Nephrol 1996; 16:462-70. [PMID: 8955756 DOI: 10.1159/000169045] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Long-acting natriuretic peptide (LANP), vessel dilator (VSDL), and atrial natriuretic factor (ANF) consisting of amino acids 1-30, 31-67, and 99-126 of the 126 amino acid ANF prohormone, respectively, circulate in humans and have potent natriuretic properties. To determine whether these peptides have a direct relationship to serum Na and/or Cl, we examined 21 24-hour profiles of these peptides and Na and Cl in 14 healthy humans. LANP, VSDL, ANF, and Cl had significant (p < 0.001) circadian rhythms with peak concentrations at 04.00 h. The circadian rhythm of serum Na was exactly opposite. Sodium correlated negatively with LANP (p = 0.021) and ANF (p = 0.007), while Cl correlated positively with LANP (p = 0.003) and VSDL (p = 0.001). These data suggest that the atrial peptides may be important for the maintenance of serum Na and Cl within their normal ranges and in the modulation of their daily circadian rhythms.
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Affiliation(s)
- R B Sothern
- Rhythmometry Laboratory, St. Paul-Ramsey Medical Center, Minneapolis, Minn, USA
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Nichols R, McCormick JB, Lim IA, Starkman JS. Spatial and temporal analysis of the Drosophila FMRFamide neuropeptide gene product SDNFMRFamide: evidence for a restricted expression pattern. Neuropeptides 1995; 29:205-13. [PMID: 8584138 DOI: 10.1016/0143-4179(95)90062-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The expression of SDNFMRFamide, one of five different FMRFamide-containing peptides encoded by the Drosophila melanogaster FMRFamide gene, has been determined. To study expression, we generated antisera to the N-terminus of SDNFMRFamide to avoid crossreactivity with FMRFamide-containing peptides. The antisera were purified and the specificity characterized. SDNFMRFamide immunoreactive material is present in the central nervous system throughout development. Immunoreactivity is first observed in embryonic neural tissue in a cluster of cells in the subesophageal ganglion and immunoreactive fibers projecting from these cells to the brain and ventral ganglion. This pattern of expression is also observed in neural tissue dissected from larva, pupa, and adult. Double-labelling experiments indicate that cells recognized by SDNFM-antisera are also stained with FMRFamide antisera. Based on position, SDNFMRFamide immunoreactive material is expressed in a limited number of cells that contain the FMRFamide polypeptide precursor. This finding suggests that the Drosophila FMRFamide precursor undergoes differential post-translational processing.
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Affiliation(s)
- R Nichols
- Department of Biological Chemistry, University of Michigan, Ann Arbor 48109-1048, USA
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Fisher-Hoch SP, Tomori O, Nasidi A, Perez-Oronoz GI, Fakile Y, Hutwagner L, McCormick JB. Review of cases of nosocomial Lassa fever in Nigeria: the high price of poor medical practice. BMJ 1995; 311:857-9. [PMID: 7580496 PMCID: PMC2550858 DOI: 10.1136/bmj.311.7009.857] [Citation(s) in RCA: 221] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To investigate two hospital outbreaks of Lassa fever in southern central Nigeria. SETTING Hospitals and clinics in urban and rural areas of Imo State, Nigeria. DESIGN Medical records were reviewed in hospitals and clinics in both areas. Patients with presumed and laboratory confirmed Lassa fever were identified and contracts traced. Hospital staff, patients, and local residents were questioned, records were carefully reviewed, and serum samples were taken. Serum samples were assayed for antibody specific to Lassa virus, and isolates of Lassa virus were obtained. RESULTS Among 34 patients with Lassa fever, including 20 patients, six nurses, two surgeons, one physician, and the son of a patient, there were 22 deaths (65% fatality rate). Eleven cases were laboratory confirmed, five by isolation of virus. Most patients had been exposed in hospitals (attack rate in patients in one hospital 55%). Both outbreak hospitals were inadequately equipped and staffed, with poor medical practice. Compelling, indirect evidence revealed that parenteral drug rounds with sharing of syringes, conducted by minimally educated and supervised staff, fuelled the epidemic among patients. Staff were subsequently infected during emergency surgery and while caring for nosocomially infected patients. CONCLUSION This outbreak illustrates the high price exacted by the practice of modern medicine, particularly use of parenteral injections and surgery, without due attention to good medical practice. High priority must be given to education of medical staff in developing countries and to guidelines for safe operation of clinics and hospitals. Failure to do so will have far reaching, costly, and ultimately devastating consequences.
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Affiliation(s)
- S P Fisher-Hoch
- Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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38
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Abstract
Crimean-Congo Haemorrhagic Fever (CCHF) is an often-lethal haemorrhagic fever caused by a tick-borne virus. There are no published data on ribavirin treatment of CCHF-infected patients, despite established in-vitro and in-vivo sensitivity. We report three health workers--two surgeons and a hospital worker--infected with CCHF virus in Pakistan who were treated with oral ribavirin 4 g/day for four days, then 2.4 g/day for six days. Intravenous ribavirin was unavailable. All three patients were severely ill with low platelet and white-cell counts, raised aspartate transaminase and evidence of impaired haemostasis. Based on published reports, all had an estimated probability of death of 90% or more. The patients became afebrile, and their haematological and biochemical abnormalities returned to normal within 48 h of ribavirin treatment; all made a complete recovery, and developed IgG and IgM antibody to CCHF virus. Our experience with ribavirin treatment is encouraging, but does not constitute evidence of efficacy. Given the difficulties in gathering adequate treatment data, we propose a consensus protocol for both intravenous and oral treatment of CCHF. This protocol could be distributed to key medical personnel in areas endemic for CCHF and used to provide a firm basis for effective treatment recommendations.
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Affiliation(s)
- S P Fisher-Hoch
- Department of Pathology, Aga Khan University, Karachi, Sindh, Pakistan
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39
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Li YL, Ruo SL, Tong Z, Ma QR, Liu ZL, Ye KL, Zhu ZY, McCormick JB, Fisher-Hoch SP, Xu ZY. A serotypic study of hemorrhagic fever with renal syndrome in rural China. Am J Trop Med Hyg 1995; 52:247-51. [PMID: 7694967 DOI: 10.4269/ajtmh.1995.52.247] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Apodemus agrarius was trapped in the fields and Rattus norvegicus was trapped within the houses in the villages of Jiande County, a region in the Zhejiang Province of China endemic for hemorrhagic fever with renal syndrome (HFRS). Antibodies to hantaviruses were detected in three (16.7%) of 18 A. agrarius and 12 (13.5%) of 89 R. norvegicus, whereas hantavirus antigens were detected in the lung tissues of four (22.2%) of 18 and nine (10.1%) of 89 of these rodents, respectively. Three hantaviruses, one from A. agrarius and two from R. norvegicus, were isolated and found to be antigenically similar to Hantaan and Seoul serotype viruses, respectively. A serologic study of 437 clinically defined HFRS patients conducted in Jiande County in 1988 revealed that the ratio of Hantaan (72.5%) to Seoul (26.8%) serotype virus infections was 2.7:1. Two epidemic seasons were found, with a major peak in November and a minor peak in June, and both were associated with Hantaan serotype virus infections that coincided with two seasonal peaks of the A. agrarius population and local agricultural activities in the fields. Seoul serotype virus infections occurred with a small peak during the months of December through May, in which in-house activities were dominant. All data suggested that Jiande County was an area endemic for HFRS, predominantly of the Hantaan virus serotype, combined with Seoul serotype virus infections.
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Affiliation(s)
- Y L Li
- Department of Epidemiology, School of Public Health, Shanghai Medical University, China
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40
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Ruo SL, Li YL, Tong Z, Ma QR, Liu ZL, Tang YW, Ye KL, McCormick JB, Fisher-Hoch SP, Xu ZY. Retrospective and prospective studies of hemorrhagic fever with renal syndrome in rural China. J Infect Dis 1994; 170:527-34. [PMID: 7915747 DOI: 10.1093/infdis/170.3.527] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Residents of two villages in Zhejiang Province, China, were interviewed and serum samples were collected to assess prevalence of hantavirus infection. Antibody prevalence was 12% (219/1811), with a ratio of illness to infection of 1.0:5.4. Seroprevalence increased with age, but no association was found with sex. There was also no evidence of vertical transmission. One year later, 2.3% (30/1325) of seronegative subjects had seroconverted including 2 who had hemorrhagic fever with renal syndrome. Peak incidence of infection occurred in those 15-39 years old. Hantaan was the dominant serotype; Seoul serotype was less common (5:1). Host reservoirs were Apodemus agrarius in agricultural fields and Rattus norvegicus in houses. Risk factors for infection were traces of rat-contaminated food, travel to other areas for farm work, direct rodent contact, camping in grain fields, living in a house on the periphery of a village, stacking straw stacks outside houses, and keeping cats. All may provide exposure to infectious rodent reservoirs.
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Affiliation(s)
- S L Ruo
- Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333
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41
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Abstract
Amino-acid sequencing of the purified major nucleoprotein (NP), VP35 and VP40 from purified Ebola virus proved that they are the protein products of the first three genes, and that the open reading frame (ORF) of the NP begins at nucleotide 470. Because of the many unusual features of the ORFs of Ebola virus, we thought that our conclusions should be substantiated. Comparisons of in vitro-translation products to purified viral proteins were used to demonstrate conclusively that the NP, VP35 and VP40 were the protein products of genes one, two, and three, respectively. Studies using antibodies to synthetic peptides matching the N- and C-termini of the deduced sequences from these genes confirmed these conclusions and that the ORF for the NP begins at nucleotide 470. Subsequent studies confirmed that VP30 is encoded by the fifth gene.
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Affiliation(s)
- L H Elliott
- Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
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42
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Trappier SG, Conaty AL, Farrar BB, Auperin DD, McCormick JB, Fisher-Hoch SP. Evaluation of the polymerase chain reaction for diagnosis of Lassa virus infection. Am J Trop Med Hyg 1993; 49:214-21. [PMID: 8357084 DOI: 10.4269/ajtmh.1993.49.214] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We evaluated the polymerase chain reaction (PCR) and hybridization procedures for diagnosis of Lassa fever. Primers were derived from a region of the small RNA segment of Lassa virus coding for the glycoprotein. Serum samples stored for a 14-year period from patients in Sierra Leone, West Africa were examined retrospectively. Blinded samples were then tested prospectively. Eighty-eight virus isolation-negative control sera were negative by PCR and hybridization. In the retrospective study, virus was isolated from 51 of 98 specimens from patients with Lassa fever, and 33 of these were positive for Lassa virus RNA by PCR, and 42 by PCR and hybridization. Fifteen were positive by PCR and hybridization but isolation-negative, and nine were positive by isolation but PCR/hybridization-negative. Thirty-two were negative by all methods (sensitivity by PCR/hybridization compared with virus isolation 0.82, specificity 0.68). In a prospective blinded study of 195 patient sera, 51 were positive by PCR and virus isolation, and 24 were PCR positive but virus isolation-negative (sensitivity 0.66, specificity 0.71). After hybridization, 66 virus isolation-positive sera were positive. The sensitivity was 0.86 and the specificity was 0.59, and the probability of false-positive results compared with virus isolation was 32%, (chi 2 = 21.9, by McNemar's test). Since some specimens may not have contained viable virus, we re-analyzed the data of individual patients using laboratory-confirmed case definitions for Lassa fever. All specimens from patients in whom Lassa fever was excluded by serologic tests were negative by PCR/hybridization.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S G Trappier
- Special Pathogens Branch, National Center of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
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43
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Xu X, Ruo SL, McCormick JB, Fisher-Hoch SP. Immunity to Hantavirus Challenge in Meriones Unguiculatus Induced by Vaccinia-Vectored Viral Proteins. Am J Trop Med Hyg 1992; 47:397-404. [PMID: 1359802 DOI: 10.4269/ajtmh.1992.47.397] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Vaccinia virus recombinants were constructed that incorporated genomic sequences coding for the nucleoprotein (N) and glycoproteins (G1 and G2) of the hantavirus R22 strain isolated from a rat in China, and designated as RNV and RMV9, respectively. The proteins expressed by RNV and RMV9 were identified by radioimmunoprecipitation and indirect immunofluorescence assay using a panel of monoclonal antibodies and polyclonal immune sera, and were found to be antigenically indistinguishable from authentic R22 viral proteins. Both RNV and RMV9 elicited an anti-R22 antibody response in Mongolian gerbils (Meriones unguiculatus) with titers ranging from 6,400 to 12,800 by enzyme-linked immunosorbent assay, but only RMV9 produced neutralizing antibodies to R22 virus (titer 1:200) and Hantaan (HTN) virus (titer 1:20). The ability of these recombinants to protect Mongolian gerbils against challenge with R22 and HTN viruses was examined. The RMV9 recombinant induced a complete protective immune response against challenge with 10(4) plaque-forming units (PFU) of both R22 and HTN viruses, while RNV induced partial protection against a challenge with the homologous R22 virus and the heterologous HTN virus at a dose of 10(3) PFU. Our data show that the common antigenic sites responsible for eliciting a protective response are located mainly on hantavirus glycoproteins, and that the nucleoprotein may also confer partial cross-protection that presumably involves cell-mediated as well as humoral mechanisms.
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Affiliation(s)
- X Xu
- Special Pathogens Branch, National Center for Infectious Diseases, Centers for Disease for Control, Atlanta, Georgia
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44
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Fisher-Hoch SP, McCormick JB, Swanepoel R, Van Middlekoop A, Harvey S, Kustner HG. Risk of human infections with Crimean-Congo hemorrhagic fever virus in a South African rural community. Am J Trop Med Hyg 1992; 47:337-45. [PMID: 1524147 DOI: 10.4269/ajtmh.1992.47.337] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Crimean-Congo hemorrhagic fever (CCHF) virus is widely distributed in wild and domestic mammals, birds, and ticks throughout many regions of Africa, Europe, and Asia. Interviews were conducted with 484 individuals from nine farms in the Republic of South Africa from which recent human CCHF cases had originated and with individuals from 27 farms without recognized cases. Serum samples were obtained from all consenting individuals. Blood was also drawn from 2,212 farm animals. Human infection with CCHF virus was uncommon (point prevalence 12.6/1,000). Antibody prevalence in humans on farms increased with age (P less than 0.001), and was correlated with handling lambs. Overall, a greater number of older animals were antibody positive than animals less than one year of age (P less than 0.001), but 12.7% of young animals on farms with human were antibody positive compared with 5.8% on those farms without human infection (P less than 0.05). Physical contact with ticks or tick bite was also found to be a risk factor, but contact with animal blood or fresh meat was not. The risk of CCHF virus infection in the community increased seven-fold following contact with a recognized CCHF case, even when other risk factors were taken into account (point prevalence rate 4.7%). In contrast, antibody prevalence was less than 1% (1 of 128) in the local hospital staff who had cared for patients with CCHF. Prevention is best achieved by education of the farming community and establishing and maintaining awareness in the hospital staff.
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Affiliation(s)
- S P Fisher-Hoch
- Special Pathogens Branch, Centers for Disease Control, Atlanta, Georgia
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45
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Cummins D, Bennett D, Fisher-Hoch SP, Farrar B, Machin SJ, McCormick JB. Lassa fever encephalopathy: clinical and laboratory findings. J Trop Med Hyg 1992; 95:197-201. [PMID: 1597876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Clinical and laboratory findings are reported in nine patients who developed acute encephalopathy during the course of Lassa fever. The encephalopathy manifested 3-17 days after disease onset with confusion, followed rapidly by tremor (seven patients), grand mal convulsions (seven), abnormal posturing (three) and coma (eight); focal neurological signs and evidence of raised intracranial pressure were not seen. Eight patients died, most commonly from respiratory arrest following a protracted fit. Development of encephalopathy did not correlate with the presence of virus in cerebrospinal fluid (CSF), nor with virus antibodies in CSF and/or serum; thus, neither direct cytopathic nor immune-mediated mechanisms seem to be involved in its pathogenesis.
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Affiliation(s)
- D Cummins
- Department of Haematology, University College, London
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46
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Abstract
We attempted to protect three rhesus monkeys from Lassa fever by vaccination with a preparation of purified whole Lassa virus which had been inactivated by gamma irradiation. The vaccinated monkeys developed antibodies against the three major viral proteins of Lassa virus demonstrated by radioimmunoprecipitation. When the three vaccinated monkeys and two unvaccinated control monkeys were challenged all five became severely ill and died. Prior to death a secondary, high-titer antibody response to Lassa virus was observed in the three vaccinated monkeys, whereas the two unvaccinated monkeys developed a primary, low-titer antibody response. Though titers of Lassa virus in serum reached peak levels earlier following challenge in the non vaccinated, at the time of death serum and organ virus titers did not differ significantly. Changes in platelet aggregation, leukocyte counts, and liver enzymes, abnormalities of which have been associated with severity of Lassa fever, were found to be comparable in the two groups. The humoral antibody response measured in these animals following vaccination, although of the same magnitude as found in humans recovered from Lassa fever, was insufficient to protect the animals from this fatal disease. Evidence is now accumulating that the cell-mediated immune response must be activated in order to protect against challenge with arenaviruses.
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Affiliation(s)
- J B McCormick
- National Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia 30333
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47
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Dykewicz CA, Dato VM, Fisher-Hoch SP, Howarth MV, Perez-Oronoz GI, Ostroff SM, Gary H, Schonberger LB, McCormick JB. Lymphocytic choriomeningitis outbreak associated with nude mice in a research institute. JAMA 1992; 267:1349-53. [PMID: 1740856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE After an employee at a cancer research institute was diagnosed with lymphocytic choriomeningitis, an investigation was performed to determine the extent of lymphocytic choriomeningitis virus (LCMV) infections among the institute's employees and to identify risk factors for infection. DESIGN Retrospective cohort study. SETTING A US cancer research institute. PARTICIPANTS Eighty-two of 90 institute employees. MAIN OUTCOME MEASURES Serum LCMV antibodies. RESULTS Seven workers (9%) with definite LCMV infection (LCMV IgG antibody titer greater than or equal to 16) and one worker (1%) with probable infection (IgG titer = 8) were identified (10% overall seroprevalence). All infected employees handled animals or animal tissues and were more likely than other animal handlers to have worked with nude mice (Mus musculus) (P less than .02). Among the 31 employees who worked with nude mice at the institute, infected workers were more likely to clean the cages of nude mice (P much less than .001), change their bedding (P less than .01), and change their water (P less than .001). The institute had been injecting nude mice with LCMV-infected tumor cell lines and had recently increased the nude mouse population and the duration of experiments. These changes would have increased the LCMV burden at the facility and were temporally associated with the cluster of LCMV infections in employees. CONCLUSIONS This LCMV outbreak, the first reported since 1974, is the first associated with nude mice. It illustrates the ongoing hazard LCMV poses in research laboratories. Since the symptoms of LCMV infection can be nonspecific, clinicians should consider this diagnosis in ill patients who report laboratory rodent exposure.
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Affiliation(s)
- C A Dykewicz
- Division of Viral and Rickettsial Diseases, Centers for Disease Control, Atlanta, GA 30333
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48
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Xu XA, Ruo SL, Tang YW, Fisher-Hoch SP, McCormick JB. Molecular characterization and expression of glycoprotein gene of Hantavirus R22 strain isolated from Rattus norvegicus in China. Virus Res 1991; 21:35-52. [PMID: 1962503 DOI: 10.1016/0168-1702(91)90070-c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A cDNA containing the complete open reading frame of the M genome segment of Hantavirus R22 strain isolated from Rattus norvegicus in China, was amplified by polymerase chain reaction (PCR), and then cloned. The M segment is 3656 nucleotides in length with a predicted region of 3402 bases encoding a precursor glycoprotein of 1134 amino acids subsequently processed into viral glycoproteins 1 and 2 (G1 and G2). A strain comparison between R22 and SR11 (isolated from a rat in Japan), and Hantaan 76-118 (isolated from Apodemus in Korea), and Hallnas B1 (isolated from a bank vole in Sweden) revealed 95%, 74%, and 53% homologies at the deduced amino acid sequence level respectively. This suggests that the rodent host species may be a more important determinant of genetic relationships than geographic proximity. Six potential asparagine linked glycosylation sites (five in G1 and one in G2) were identified, and among them all are conserved in SR11, five in Hantaan virus and four in Hallnas B1 virus. Although different degrees of homology exist among these four viruses at amino acid sequence level, more than 90% of the cysteine residues are conserved, suggesting that structural homology may be very strong between the Hantaviruses. Genetic differences in the M segment genome of R22 and SR11 viruses, within the same serotype viruses, were found as random coding changes; some limited to single amino acids, others in clusters. A recombinant vaccinia virus that contained the fully activated M segment cDNA of R22 was constructed. This recombinant virus expressed two glycoproteins G1 and G2 identical to R22 virus G1 and G2 in molecular weight, cleavage pattern and cellular immunofluorescent patterns.
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Affiliation(s)
- X A Xu
- Special Pathogens Branch, Centers for Disease Control, Atlanta, GA 30333
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49
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Tang YW, Li YL, Ye KL, Xu ZY, Ruo SL, Fisher-Hoch SP, McCormick JB. Distribution of hantavirus serotypes Hantaan and Seoul causing hemorrhagic fever with renal syndrome and identification by hemagglutination inhibition assay. J Clin Microbiol 1991; 29:1924-7. [PMID: 1685497 PMCID: PMC270236 DOI: 10.1128/jcm.29.9.1924-1927.1991] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
An epidemiologic evaluation of patients with hemorrhagic fever with renal syndrome from different locations in the People's Republic of China was conducted to define the prevalence of two Hantavirus serotypes, Seoul (SEO) and Hantaan (HTN). Serum specimens were collected between 5 and 14 days after the onset of illness and were tested for antibodies by both hemagglutination inhibition (HI) and plaque reduction neutralization (PRN). By the HI test, the geometric mean titer (GMT) of antibodies to SEO in the sera from individuals from Kaifeng City of Henan Province was five times higher than that to HTN. In contrast, by the HI test, the sera from individuals from Jiande County of Zhejiang Province had a GMT of antibodies to HTN that was seven times higher than that to SEO. In the sera from individuals from Shanghai, only a twofold difference was observed in HI antibody titers to the two hemagglutinins by the HI test, with that to HTN being higher than that to SEO. By the PRN test, the GMT ratios of antibody between HTN and SEO strains from individuals in Kaifeng, Jiande, and Shanghai were found to be 1:13, 14:1, and 2:1 respectively. A close correlation (r = 0.8219) and concordance rate (78.3%) were observed between the PRN and HI tests for the identification of the serotypes of individual cases of hemorrhagic fever with renal syndrome. The hantavirus serotypes from individuals in Kaifeng and Jiande were identified as predominantly SEO and HTN, respectively, and those from individuals in Shanghai had an indeterminant serotype defined by these two techniques. The HI test appears to be a simple and reliable way of determining the predominant hantavirus that causes HFRS in a given geographic area.
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Affiliation(s)
- Y W Tang
- Department of Epidemiology, School of Public Health, Shanghai Medical University, People's Republic of China
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50
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Ruo SL, Sanchez A, Elliott LH, Brammer LS, McCormick JB, Fisher-Hoch SP. Monoclonal antibodies to three strains of hantaviruses: Hantaan, R22, and Puumala. Arch Virol 1991; 119:1-11. [PMID: 1907448 DOI: 10.1007/bf01314318] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Thirty hybrid cell lines that produce monoclonal antibodies to three strains of hantaviruses have been generated and characterized. One clone specific to Hantaan 76-118 strain, four clones specific to Rattus strains and one clone specific to Puumala virus have been identified. Most of the monoclones produced antibodies specific to nucleoproteins. Only two monoclones were found to produce glycoprotein specific, neutralizing antibodies. The immunofluorescent (IFA) staining patterns of the monoclonal antibodies show consistent correlation with viral protein specificities as described for other hemorrhagic fever viruses. Cross-reactivity studies with hantaviruses tested demonstrate conserved antigenic sites on nucleoproteins among these hantaviruses tested. Puumala specific monoclones, produced for the first time, reveal both conserved and strain specific sites on the viral nucleoproteins of the Scandinavian virus.
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Affiliation(s)
- S L Ruo
- Division of Viral and Rickettsial Diseases, Centers for Disease Control, Atlanta, Georgia
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