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C Ferreccio

Publications and source records attributed to C Ferreccio.

At least 19 recordsLinked to original sources
PubMed2000

Lung cancer and arsenic concentrations in drinking water in Chile.

Cities in northern Chile had arsenic concentrations of 860 microg/liter in drinking water in the period 1958-1970. Concentrations have since been reduced to 40 microg/liter. We investigated the relation between lung cancer and arsenic in drinking water in northern Chile in a case-control study involving patients diagnosed with lung cancer between 1994 and 1996 and frequency-matched hospital controls. The study identified 152 lung cancer cases and 419 controls. Participants were interviewed regarding drinking water sources, cigarette smoking, and other variables. Logistic regression analysis revealed a clear trend in lung cancer odds ratios and 95% confidence intervals (CIs) with increasing concentration of arsenic in drinking water, as follows: 1, 1.6 (95% CI = 0.5-5.3), 3.9 (95% CI = 1.2-12.3), 5.2 (95% CI = 2.3-11.7), and 8.9 (95% CI = 4.0-19.6), for arsenic concentrations ranging from less than 10 microg/liter to a 65-year average concentration of 200-400 microg/liter. There was evidence of synergy between cigarette smoking and ingestion of arsenic in drinking water; the odds ratio for lung cancer was 32.0 (95% CI = 7.2-198.0) among smokers exposed to more than 200 microg/liter of arsenic in drinking water (lifetime average) compared with nonsmokers exposed to less than 50 microg/liter. This study provides strong evidence that ingestion of inorganic arsenic is associated with human lung cancer.

Adult↗
PubMed2000

Chronic arsenic exposure and risk of infant mortality in two areas of Chile.

Chronic arsenic exposure has been associated with a range of neurologic, vascular, dermatologic, and carcinogenic effects. However, limited research has been directed at the association of arsenic exposure and human reproductive health outcomes. The principal aim of this study was to investigate the trends in infant mortality between two geographic locations in Chile: Antofagasta, which has a well-documented history of arsenic exposure from naturally contaminated water, and Valparaíso, a comparable low-exposure city. The arsenic concentration in Antofagasta's public drinking water supply rose substantially in 1958 with the introduction of a new water source, and remained elevated until 1970. We used a retrospective study design to examine time and location patterns in infant mortality between 1950 and 1996, using univariate statistics, graphical techniques, and Poisson regression analysis. Results of the study document the general declines in late fetal and infant mortality over the study period in both locations. The data also indicate an elevation of the late fetal, neonatal, and postneonatal mortality rates for Antofagasta, relative to Valparaíso, for specific time periods, which generally coincide with the period of highest arsenic concentration in the drinking water of Antofagasta. Poisson regression analysis yielded an elevated and significant association between arsenic exposure and late fetal mortality [rate ratio (RR) = 1.7; 95% confidence interval (CI), 1.5-1.9], neonatal mortality (RR = 1.53; CI, 1.4-1.7), and postneonatal mortality (RR = 1.26; CI, 1.2-1.3) after adjustment for location and calendar time. The findings from this investigation may support a role for arsenic exposure in increasing the risk of late fetal and infant mortality.

Arsenic↗
PubMed1999

Duration of efficacy of Ty21a, attenuated Salmonella typhi live oral vaccine.

Currently, two different formulations of Ty21a live oral typhoid vaccine are commercialized. The enteric-coated capsule formulation was licensed based on results of three years of follow-up of a randomized, placebo-controlled, double-blind field trial in Area Occidente, Santiago, Chile, which demonstrated that three doses of this formulation, given on an every other day immunization schedule, conferred the best protection among several options evaluated. Subsequently, a liquid formulation (lyophilized vaccine organisms reconstituted with buffer and water into a vaccine cocktail) was commercialized after it was shown to provide superior protection than enteric-coated capsules over three years of follow-up in a randomized, placebo-controlled field trial in Area Sur Oriente and Area Norte, Santiago. Surveillance in the Area Occidente trial was continued for four additional years (i.e., total seven years of follow-up) and in the Area Sur Oriente/Area Norte trial for two additional years (i.e., a total of five years of follow-up). These additional surveillance data, which were analyzed to ascertain the longevity of protection conferred by these formulations of Ty21a, revealed that three doses of Ty21a in enteric-coated capsules (every other day schedule) conferred 67% protection over three years and 62% protection over seven years of follow-up, whereas three doses of liquid formulation (every other day schedule) elicited 77% protection over three years and 78% over five years of follow-up. Based on its excellent clinical acceptability, ease of oral administration, proven practicality in school-based mass immunization, and long-term efficacy enduring at least seven years, it is proposed that school-based immunization with Ty21a be utilized as a control measure in areas where the incidence of typhoid fever is high and Salmonella typhi are antibiotic-resistant.

Administration, Oral↗
PubMed1998

Lung cancer and arsenic exposure in drinking water: a case-control study in northern Chile.

In some Chilean cities, levels of arsenic (As) in drinking water reached 800 (micrograms/L between 1950 and 1970, while current levels are 40 (micrograms/L. To evaluate the causal role of this exposure in lung and bladder cancers, we conducted a case-control study in Regions I, II, and III of the country. From 1994 to 1996, cases diagnosed as lung cancer and two hospital controls were entered in the study; one control was a patient with a cancer, while the other was a patient without cancer, both conditions unrelated to As. Controls were matched with cases by age and sex. A standard survey containing questions about residence, employment, health history, was administered to study subjects. Data on As concentrations in water were obtained from records of the municipal water companies. A total of 151 lung cancer cases and 419 controls (167 with cancer and 242 without cancer) were enrolled. Median level of lifetime As exposure was significantly higher among cases, with a clear dose-response relationship between mean As exposure levels, with an OR (95% CI) of: 1, 1.7 (0.5-5.1), 3.9 (1.2-13.4), 5.5 (2.2-13.5), and 9.0 (3.6-22) for strata one to five respectively. This study provides new evidence that As in drinking water can cause internal cancers and gives an estimate of the form of this relationship.

Arsenic↗
PubMed1997

[Seroprevalence of cytomegalovirus and Toxoplasma gondii in healthy subjects under 30 years old in Santiago, Chile].

BACKGROUND: Infections by Cytomegalovirus and Toxoplasma gondii are endemic in Chile and only a low proportion of infected individuals have clinical manifestations. AIM: To study the prevalence of infection by Cytomegalovirus and Toxoplasma gondii in Chile. SUBJECTS AND METHODS: The prevalence of IgG antibodies against Cytomegalovirus and Toxoplasma gondii were studied in 560 subjects under 30 years old, using an ELISA technique. Age, socioeconomic level, breast feeding, assistance to nurseries and number of family members were considered as risk factors for these infections. RESULTS: Infection by Cytomegalovirus had a global prevalence of 60%. It showed an epidemiological pattern of late acquisition in high socioeconomic levels and a pattern of early infection in medium and low socioeconomic levels. Eighty to 90% of sera were positive for the infection in adult subjects of the three socioeconomic levels. There was a positive correlation between the duration of breast feeding and the frequency of Cytomegalovirus infection. Infection by Toxoplasma gondii had a global prevalence of 24.6%. The rates of susceptible individuals were 80 and 50% in high and medium-low socioeconomic levels respectively. CONCLUSIONS: The knowledge about the frequency of these infections in high risk populations such as women during their reproductive years and immunodepressed individuals, will allow the implementation of preventive measures.

Adolescent↗
PubMed1996

[Bronchopulmonary cancer in workers exposed to arsenic: a case control study].

Case-control methodology was used to assess lung cancer risk from exposure to arsenic in air, employing data from former workers in different units at the Chuquicamata copper mine and smelter complex. Thirty two workers from this complex were identified among the lung cancer deaths that occurred in the Northern region of Chile between 1987 and 1991. Each case was matched on age and sex, with controls that had a similar date of enrolment in the company. Available data on arsenic concentrations in air for six work sites were compiled from 1952 to 1991 and these were used to categorize the workplaces: Administrative area (1.6 micrograms/m3), Mine (2.3 micrograms/m3), Oxid Plant (3.1 micrograms/m3), Workshop and Services (9.8 micrograms/m3), Sulphur Plant (8.4 micrograms/m3) and Smelter (201.7 micrograms/m3). The results indicate an Odds Ratio of 5.7 (Fisher's p = 0.016) of dying from lung cancer among workers of the smelter compared with the rest of the workers.

Adolescent↗
PubMed1996

[Natural history of human immunodeficiency virus infection in a cohort of Chilean patients].

We characterized clinical manifestations and the risk to develop AIDS in a cohort of 32 patients infected with human immunodeficiency virus without AIDS A multivariate analysis was performed to determine association between the progression of infection and control variables (socioeconomic level, age, sex and sexual preferences) and causal variables (psycho-social changes, significant clinical events, stress scoring and sexual activity). The cumulative AIDS incidence, defined as a CD4 lymphocyte count below 200 cells/cm3 was 50% at 6.5 years and 82% at 8 years. Using clinical criteria to define AIDS, 50% developed the disease at 8 years of follow up. Among studied factors, only age (faster progression at higher age) and time of evolution were associated with progression in stages before AIDS, the most frequent diseases were acute diarrhea, sexual transmission diseases, oral candidiasis, sinusitis and varicella zoster infections. The reduction; of CD4 lymphocytes-below 200 cells/cm3 always preceded the symptoms of the disease. Two patients have remained more than eight years without clinical or immunological deterioration.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Seroprevalence of Epstein Barr virus infection in a healthy population of Santiago de Chile].

To study the rate of infection by Epstein Barr virus (EBV) in Santiago, Chile, the prevalence of antibody to the viral capsid antigen (VCA-IgG) was determined in a group of 663 healthy individuals grouped by age and socioeconomic level (SEL). In addition, several risk factors for infection were studied. VCA-IgG was determined by ELISA. The total prevalence was 76.7%. When grouped by age and SEL, 50% of the children from low and medium SEL had been already infected by the age two, compared to 5.9% in the high SEL (p < 0.01). However, by age twenty, 90% of the total sample had already specific antibodies to EBV. Age and number of household members were positively associated with the infection. High socioeconomic level represented a delay factor in the acquisition of the virus, (p < 0.01). These results show that EBV infection is frequent in Santiago, occurring early in childhood among medium and low SEL. Hence, the classical infectious mononucleosis should be recognized more frequently among adolescents and young adults belonging to high SEL, while the clinical spectrum of associated manifestations different from the typical mononucleosis syndrome should be investigated among those exposed in early age.

Adolescent↗
PubMed1993

Epidemiologic studies of Escherichia coli diarrheal infections in a low socioeconomic level peri-urban community in Santiago, Chile.

The incidence of diarrhea due to six categories of diarrheogenic Escherichia coli was determined in two pediatric cohorts in a low socioeconomic level community in Santiago, Chile, with access to chlorinated water. An age cross-sectional cohort of 340 children aged birth to 47 months was assembled. A newborn cohort was assembled by enrolling 10-12 newborns monthly for 12 months. Episodes of diarrhea were detected by twice weekly household visits. E. coli from stool cultures of cases and matched controls were hybridized with DNA probes specific for enterotoxigenic, enteroinvasive, enteropathogenic, enterohemorrhagic, enteroaggregative, and diffuse adherence E. coli. Overall, the incidence of diarrhea was low (2.1 episodes/infant/year). Nevertheless, a putative E. coli enteropathogen was found in a large proportion of diarrheal episodes, particularly during the summer. In both cohorts, enterotoxigenic E. coli were important pathogens. Enteropathogenic E. coli were incriminated during the first year of life in the newborn cohort, where they were found significantly more often in cases (p = 0.021) than in controls; beyond this age, isolation rates were similar. In contrast, the relative risk of isolation of diffuse adherence E. coli increased with age in the age cross-sectional cohort, where, overall, the difference in rate of isolation between cases and controls was significant (p = 0.0024). Enteroinvasive and enterohemorrhagic E. coli were isolated infrequently. Enteroaggregative E. coli were encountered equally in cases and controls. Facile transmission of E. coli enteropathogens is occurring in this community despite the availability of potable water.

Case-Control Studies↗
PubMed1993

Cost-benefit analysis for the use of Haemophilus influenzae type b conjugate vaccine in Santiago, Chile.

Cost-benefit analyses can be integral to the evaluation of interventions in developing countries. The authors compare the potential benefits to the Chilean Ministry of Health, in terms of treatment costs averted, by prevention of Haemophilus influenzae type b (HIB) invasive disease, with the costs of adding HIB conjugate vaccine to the diphtheria-tetanus-pertussis (DTP) immunization routinely administered to infants. In their basecase model, over a 10-year period (1991-2000), vaccination against HIB will prevent 1,229 cases of HIB invasive disease, including 713 cases of meningitis, 107 of whom would suffer severe, long-term sequelae, and between 29 and 116 deaths. Assuming a cost of US$1 for a full three-dose regimen of vaccine, the benefit/cost ratio of 1.66, with a net discounted savings of over $403,225, illustrates that HIB vaccine can be cost-beneficial. Sensitivity analyses which alter each of the variables in the analysis indicate that if the true incidence of HIB disease is twice the published rate, then three doses of vaccine remains cost-beneficial at US#3.

Bacterial Vaccines↗
PubMed1993

Seroprevalence of Helicobacter pylori in Chile: vegetables may serve as one route of transmission.

Helicobacter pylori infection is very common in Chilean adults, but the age-related prevalence, risk factors for infection, and mode of transmission in Chilean children are unknown. An ELISA was used to test for H. pylori antibodies in 1815 Chileans < 35 years of age. Seropositivity was > 60% in lower socioeconomic groups. H. pylori seropositivity correlated with increased age, low socioeconomic status, and consumption of uncooked vegetables by use of a logistic regression analysis. Risk factors that reached marginal significance were consumption of uncooked shell-fish, female sex, and residence in Santiago. Although multiple modes of transmission for H. pylori undoubtedly exist, prior studies have suggested that contamination of irrigation water by raw sewage (and the subsequent contamination of vegetables that are eaten uncooked) is a key factor in the transmission of enteric pathogens in Chile; H. pylori may be transmitted by a similar route.

Adolescent↗
PubMed1993

Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine does not depress serologic responses to diphtheria, tetanus or pertussis antigens when coadministered in the same syringe with diphtheria-tetanus-pertussis vaccine at two, four and six months of age.

The safety and immunogenicity of a vaccine against Haemophilus influenzae type b consisting of purified polyribosylribitol phosphate conjugated to tetanus toxoid (PRP-T) were evaluated in 277 Chilean infants who were randomly assigned to one of three treatment groups: Group A, PRP-T mixed with diphtheria-tetanus-pertussis (DTP) vaccine in a single syringe and given as a single inoculation in one arm and placebo in the other arm; Group B, PRP-T given in one arm and DTP in the other arm; Group C, DTP given in one arm and placebo in the other. Infants were immunized at 2, 4 and 6 months of age and examined daily for 4 days after each immunization. Serum PRP antibodies; tetanus, diphtheria and pertussis antitoxin; pertussis agglutinins; and antibodies to Bordetella pertussis filamentous hemagglutinin were measured at baseline and 2 months after each dose. PRP-T was well-tolerated. After three doses of PRP-T vaccine 100% of infants attained PRP antibody concentrations > or = 0.15 micrograms/ml and 96 to 99% achieved high anti-PRP concentrations (> or = 1.0 micrograms/ml). The post-third dose anti-PRP geometric mean titer was high (6.94 micrograms/ml) in infants who were given PRP-T combined with DTP, although it was somewhat lower than the geometric mean titer of the group who received PRP-T in a separate arm (9.93 micrograms/ml) (P not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1993

[Tolerance and immunogenicity of an oral dose of CVD 103-HgR, a live attenuated Vibrio cholerae 01 strain: a double-blind study of Chilean adults].

CVD 103-HgR is an attenuated, AB+, live, recombinant vaccine strain, developed by deletion of the toxA gen in a virulent Vibrio cholerae 01, Inada classical strain (569B). In phase II studies conducted to date, CVD 103-HgR has been well tolerated and immunogenic in volunteers from both industrialized countries and cholera-endemic areas. In this study of safety, immunogenicity and excretion, 81 Chilean adults were randomly allocated to receive, in a double blind fashion, a single oral dose of 5 x 10(9) FU of CVD 103-HgR or placebo, (5 x 10(9) heat-killed E. Coli K12 organisms), in 100 ml of buffered water. Side effects were assessed by daily visits to the participants. Immunogenicity, (vibriocidal seroconversion), was investigated in blood drawn before and on days 8 and 28 after immunization, while stool cultures to assess excretion of the vaccine strain were performed on specimens obtained on days 1 and 7. None of the participants, (40 vaccinees and 41 placebo recipients), experienced untoward effects during 30 minutes of close surveillance after ingestion of the preparation; upon follow up, neither adverse events were more frequently reported by the vaccinees. 34/40 vaccinees, and 2/41 participants receiving placebo had a significant raise, (> = fourfold), in their vibriocidal titers; (85 vs 2%, p < 0.001). The peak postimmunization geometric mean titer, (222), was ten fold higher than the baseline vibriocidal titer. The vaccine strain was recovered in stool cultures from 8 participants, one of them excreted the strain in both specimens. We conclude that CVD-103-HgR is safe and immunogenic in Chilean adults.

Administration, Oral↗
PubMed1992

Impact of Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine on responses to concurrently administered diphtheria-tetanus-pertussis vaccine.

OBJECTIVE: To assess whether serum antibody responses to diphtheria-tetanus-pertussis (DTP) vaccine were affected by coadministration of Haemophilus influenzae type b capsular polyribosylribitol phosphate polysaccharide-tetanus protein (PRP-T) conjugate vaccine when given to patients at 2, 4, and 6 months of age. DESIGN: Randomized, double-blind clinical trial. SETTING: Urban Santiago, Chile. PATIENTS: Healthy infants assembled from health centers. Two hundred seventy-eight (74%) of 375 eligible infants participated; 222, who complied with the complete protocol, constituted the primary group under analysis. INTERVENTIONS: One of three vaccine regimens was given to study participants at 2, 4, and 6 months of age, either DTP mixed in the same syringe as PRP-T (group 1); DTP and PRP-T given at separate injection sites (group 2); or DTP without PRP-T (group 3). PRIMARY OUTCOME MEASURES: Titers of serum antidiphtheria toxoid, antitetanus toxoid, and pertussis agglutinin antibodies were measured in blood samples taken from patients 2 months after each dose. RESULTS: Serum antidiphtheria toxoid and antitetanus toxoid responses showed no important depressions in the patients receiving PRP-T. In contrast, geometric mean titers (GMTs) of pertussis agglutinins, expressed as reciprocal serum dilutions, after both the second and third doses (GMT2, GMT3) were lowest in group 1 (GMT2 = 89; GMT3 = 1230), intermediate in group 2 (GMT2 = 123; GMT3 = 1995), and highest in group 3 (GMT2 = 210; GMT3 = 3090; P less than .05 for trend group 1 less than group 2 less than group 3 after each dose). Antipertussis toxin and antipertussis filamentous hemagglutinin antibody titers also were depressed in patients who received PRP-T. Follow-up of a subset at 18 months revealed an expected decline of pertussis agglutinin titers to near baseline levels in each group. CONCLUSIONS: Concurrent administration of PRP-T vaccine with DTP vaccine, either in the same syringe or at different sites, interfered with antipertussis responses to a primary series of immunizations. Although the clinical significance of this antagonism is uncertain, these data underscore the caution required in decisions to add new vaccines to existing immunization regimens.

Antibodies, Bacterial↗
PubMed1992

[Typhoid fever in school children: by what measures is the modification of the clinical course due to oral vaccination?].

The clinical course of infection by Salmonellae was compared between patients who had been vaccinated against typhoid fever using the Ty21a vaccine and those who had not. Of 2566 bacteriological confirmed cases 84% were infected with S typhi, 14% with S paratyphi B and 2% with S paratyphi A. Among patients with typhoid fever, 34% were treated in hospital, 3.5% had relapses, 5.4% developed complications and 1 patient died (0.05%). Among patients with paratyphoid fever, 18% were treated in hospital, 0.6% had relapses, 1.4% developed complications and there were no deaths. These figures were similar among vaccinated and non-vaccinated cases. A slightly greater proportion of vaccinated cases were treated in hospital (38 vs 30%). Thus, use of oral vaccination against typhoid fever does not alter the clinical course of infection with Salmonellae.

Administration, Oral↗
PubMed1991

Epidemiologic patterns of acute diarrhea and endemic Shigella infections in children in a poor periurban setting in Santiago, Chile.

To prepare a field site for evaluating preventive interventions against endemic shigellosis, the authors followed prospectively a cohort of 360 children (90 each of children aged 0-11, 12-23, 24-35, and 36-47 months) in Santa Julia, a low socioeconomic area in Santiago, Chile, from November 1986 through April 1989 with twice weekly household visits for diarrheal disease; infants replaced children who reached 60 months of age. Coprocultures on 2 consecutive days from children with diarrhea and from age-matched controls within the cohort were cultured for Shigella. Bacteriologic surveillance was also maintained in the health center and children's hospital serving Santa Julia. In this community, where all households had access to potable water (68% inside) and all but 3% had access to a toilet, but where there was marked crowding, the overall incidence of diarrheal disease in the cohort was low (2.26 episodes/12 child months of observation in children aged 0-11 months and 2.09 in those aged 12-23 months), yet Shigella infections were common. Shigella accounted for 10% of diarrheal episodes in the cohort (vs. 3.2% isolation rate in controls, p less than 0.0001). The incidence of shigellosis in children aged 12-47 months was 0.16 cases per 12 child months of observation; in the first 5 years of life, a child had a 67% chance of experiencing shigellosis. Shigella sonnei, Shigella flexneri 2a, and S. flexneri 6 caused greater than 79% of the infections. Shigella occurred more often in hospitalized cases of diarrhea than in age-matched cases detected in the health center or by household surveillance (p less than 0.0001). An initial episode of Shigella diarrhea did not diminish overall the risk of subsequent shigellosis but did confer 72% protection (p = 0.05) against illness due to the homologous serotype. The high rate of both S. sonnei and S. flexneri shigellosis in a population with a low background rate of diarrhea makes Santa Julia an appropriate site for assessing the efficacy and effectiveness of measures to reduce Shigella infections.

Acute Disease↗
PubMed1991

The clinical and immunologic response of Chilean infants to Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine coadministered in the same syringe with diphtheria-tetanus toxoids-pertussis vaccine at two, four and six months of age.

The safety and immunogenicity of a vaccine against Haemophilus influenzae type b consisting of purified polyribosylribitolphosphate conjugated to tetanus toxoid (PRP-T) was evaluated in 278 Chilean infants who were randomly assigned to one of three treatment groups: Group A, PRP-T mixed with diphtheria-tetanus toxoids-pertussis (DTP) vaccine in a single syringe and given as a single inoculation in one arm and placebo in the other arm; Group B, PRP-T given in one arm and DTP in the other arm; Group C, DTP given in one arm and placebo in the other. Infants were immunized at 2, 4 and 6 months of age and examined daily for 4 days after each immunization; serum PRP antibodies were measured at baseline and 2 months after each dose. The only adverse systemic reaction attributable to PRP-T beyond that caused by DTP alone was a 7 to 20% increase in febrile responses in the first 24 hours after the first and second doses of vaccine; the fevers were largely low grade and not accompanied by increased irritability, diminished activity or loss of appetite, compared with the group who received DTP without PRP-T. After the first dose 72% of infants who received PRP-T combined with DTP and 67% who received it in a separate arm attained antibody concentrations greater than or equal to 0.15 micrograms/ml. After two doses of PRP-T, 93 and 95%, respectively, had concentrations greater than or equal to 0.15 microgram/ml and after three doses 100% of infants who received PRP-T had such titers.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗