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V Prado

Publications and source records attributed to V Prado.

At least 19 recordsLinked to original sources
PubMed2006

Distribution of putative adhesins in Shiga toxin-producing Escherichia coli (STEC) strains isolated from different sources in Chile.

The distribution of three putative adhesin genes in 123 Shiga toxin-producing (STEC) strains was determined by PCR. The STEC strains were isolated from human patients (n=90) and food (n=33) and were characterized by serogroup, virulence markers (eae, stx(1), stx(2)) and adherence factors (efa1, lpfA(O157), saa) genes. Serogroups O157 (64.4%) and O26 (28.8%) were the most frequent among human strains and the majority (60.6%) of food strains were serologically non-typable. The adhesin genes efa1 (90%) and lpfA(O157) (73.3%) were the most common in humans strains and saa (45.5%) in food strains. The presence of these genes in addition to eae in STEC from different sources may suggest a relevant role in their pathogenesis.

Adhesins, Bacterial↗
PubMed2005

Genetic analysis of antibiotic-resistance determinants in multidrug-resistant Shigella strains isolated from Chilean children.

A total of 162 clinical isolates of Shigella collected from children in a semi-rural community of Chile were examined for the presence of genetic determinants of resistance to ampicillin, chloramphenicol, tetracycline, and trimethoprim. Ampicillin resistance was most frequently associated with the presence of bla(OXA) in S. flexneri and with bla(TEM) in S. sonnei. The bla(OXA) gene but not bla(TEM) was located in class 1 integrons. The dhfrIa gene encoding for resistance to trimethoprim was associated to class 2 integrons and detected exclusively in S. flexneri, whereas dhfrIIIc was found in all S. sonnei strains and in 10% of the S. flexneri isolates. Cat, coding for choramphenicol resistance, and bla(OXA) genes were located in the chromosome in all cases, whereas tetA gene, coding for tetracycline resistance, and bla(TEM), dhfrIa and dhfrIIIc genes were found either in the chromosome or in conjugative plasmids. Our results show a heterogenous distribution of antibiotic-resistance determinants between S. flexneri and S. sonnei.

Blotting, Southern↗
PubMed2002

Immunogenicity and reactogenicity of a combined hepatitis A and B vaccine in healthy Chilean subjects.

OBJECTIVES: A combination vaccine against hepatitis A and B provides the opportunity for simultaneous protection against both diseases with a single vaccine. This clinical study investigated the reactogenicity and immunogenicity of a combined hepatitis A and B vaccine (Twinrix, GlaxoSmithKline Biologicals, Rixensart, Belgium) in healthy Chilean adults between 18 and 40 years of age. METHODS: In total, 345 healthy, seronegative health care workers were enrolled and randomized to three groups who received one of three lots of Twinrix on a 0-, 1- and 6-month schedules. Blood samples were screened 1 month after each dose for anti-HAV and anti-HBs antibodies. Reactogenicity after each dose was assessed using diary cards. RESULTS: The nature and incidence of symptoms were similar to those reported for other Twinrix studies. Very few symptoms were scored as severe. Upon completion of the vaccination, all subjects had anti-HAV antibodies with titers $6000 mIU/mL, and all but one were protected against hepatitis B, with titers $4000 mIU/mL. CONCLUSIONS: We have demonstrated the high immunogenicity and tolerance of the combined hepatitis A and B vaccine. Combined vaccination has the advantage of offering dual protection with a reduction in the number of injections needed, lower associated costs, and a positive impact on compliance.

Adolescent↗
PubMed2002

Management of the female stimulus during semen collection and its association with libido re-establishment and semen characteristics of goats.

The effect of management of the female stimulus during semen collection and its association with libido re-establishment and the semen characteristics of sexually mature goats was evaluated. Eight 2-yr-old bucks were individually subjected to 12 weekly trials in which one of the following three treatments was applied alternately. In treatment one, each male performed two ejaculations on an estrus-induced, restrained doe and semen was collected with an artificial vagina (AV). In treatment two, males were collected as in the former treatment, but a different doe served as the stimulus female for the second ejaculation. In treatment three, two restrained does were present while collecting each buck, allowing males to choose which female to mount and serve in each of the two collections. Number of mounts before first ejaculation and reaction times (period from introduction of the ram to the test arena to his first ejaculation) were similar among treatments (P > 0.05). A significant (P < 0.05) decrease was found for number of mounts performed before achieving the second ejaculation and for latency between ejaculations in the third treatment. No differences (P > 0.05) were found for semen volume (0.8+/-0.03, 1.0+/-0.03, and 0.9+/-0.02 mL) or sperm concentration (4.4+/-0.15, 4.6+/-0.13, and 4.4+/-0.86 spermatozoa/mL) among the three treatments or between the first and second collection. However, a trend to decrease volume and concentration was observed. It was concluded that the simultaneous presence of two females while bucks are collected reduced the number of mounts performed before the second ejaculation and the latency between ejaculations.

Animals↗
PubMed2001

Detection of enterohemorrhagic Escherichia coli in meat foods using DNA probes, enzyme-linked immunosorbent assay and polymerase chain reaction.

Enterohemorrhagic Escherichia coli (EHEC) is an important cause of diarrhoea with blood and haemolytic uremic syndrome (HUS) in children and elderly people. Infections with EHEC are a world-wide public health problem, related to consumption of contaminated ground beef. The aim of this study was to establish whether different meat foods sold in Santiago, Chile pose an infection risk by EHEC and to evaluate three different diagnostic techniques in foods, to determine which is most applicable for use in Chile. A parallel analysis was performed on 64 samples of meat foods (23 refrigerated ground meat, 23 refrigerated long pork sausages and 18 frozen hamburgers) sold in Santiago, Chile using DNA probes, enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Twenty-four samples (24 of 64 = 37.5%) were positive by DNA probes, ELISA or PCR. The positive and negative predictive values, sensitivity and specificity of ELISA were 26.7, 81.6, 30.8 and 78.4%, respectively. The positive and negative predictive values, sensitivity and specificity of PCR were 91.7, 96.2, 84.6 and 98%, respectively. The EHEC serogroups most frequently isolated were O158, O157, O119, O125 and O114. These results show that, although molecular techniques such as enzyme immunoassays are useful for EHEC detection in meat foods, PCR has advantages in terms of sensitivity, specificity, cost and ease of implementation in Chile.

Animals↗
PubMed2001

[Trends of etiology of acute bacterial meningitis in Chilean children from 1989 to 1998. Impact of the anti-H influenzae type b vaccine].

BACKGROUND: Acute bacterial meningitis still has a high mortality and rate of complications. AIM: To assess the impact of anti H influenzae vaccination on the epidemiology of acute bacterial meningitis in Chilean children. MATERIAL AND METHODS: A retrospective study of hospital discharge records of patients with acute bacterial meningitis. Causative agents were studied globally, by hospital and by age group. The changes in etiology from 1989 to 1995 were also assessed. Between 1996 and 1998, only those patients with acute bacterial meningitis caused by H influenzae were recollected. RESULTS: In the period prior to vaccination (1989-1995), 1000 cases were registered. The main causative agents were N meningitidis in 33.8%, H influenzae type b in 21.9% and S pneumoniae in 15.4%. The incidence of H influenzae decreased in the period from 36.4 to 9.9% (p < 0.001) and the incidence of N meningitidis increased from 22.9 to 52.1% (p < 0.001). The incidence of S pneumoniae did not change significantly. H influenzae predominated in children between 4 and 24 months of age and N meningitidis predominated in children over 25 months of age. In the period after the introduction of vaccination (1995-1998), there was a further decrease in the incidence of H influenzae from 10 to 2% (p < 0.001). Until 1997, there was a considerable increase in the incidence of N meningitidis, specially in children over 25 months of age. It declined in 1998 to 38%. CONCLUSIONS: There was a reduction in the incidence of acute bacterial meningitis caused by H influenzae prior to the introduction of the vaccine against H influenzae type b. The decrease was more pronounced after the introduction of the vaccine.

Acute Disease↗
PubMed2001

[Profile of antimicrobial resistance of agents causing urinary tract infections in Chilean children. PRONARES surveillance program].

BACKGROUND: PRONARES (Programa Nacional de Vigilancia de Resistencia) is a national surveillance program for antimicrobial susceptibility, focused in different syndromes and among these, urinary tract infections. The work is done in a laboratory net that uses common protocols and whose data are centrally analyzed using the WHONET program. AIM: To analyze the pattern of antimicrobial susceptibility of agents causing urinary infections in children in the period 1997-1999. MATERIAL AND METHODS: In the study period, 5,525 strains were analyzed. Of these, 2,307 came from pediatric patients (1,495 hospitalized and 803 ambulatory). RESULTS: The most common causative agent was E. coli in 74.2% of cases, followed by Klebsiella spp in 8.2% and other agents in a lower frequency. Of E. coli strains, 74% were resistant to ampicillin, 52% to clotrimoxazole and 30% to first generation cephalosporins. These strains were sensitive to second and third generation cephalosporins, aminoglycosides, ciprofloxacin and nitrofurantoin. Strains from nosocomial or community infections had similar antimicrobial susceptibility. Klebsiella spp had a high rate of antimicrobial resistance (over 40%), that was even higher among nosocomial strains. It was 90% susceptible to ciprofloxacin and 100% to imipenem. All centers from which strains came had a similar pattern of susceptibility, with the exception of a pediatric center that had significantly higher resistance levels. CONCLUSIONS: The current therapeutic recommendations for urinary tract infections in children caused by E coli, are still pertinent, but the use of first generation cephalosporins must be cautious. The treatment of Klebsiella spp requires an individual antibiogram.

Adolescent↗
PubMed2000

[Prevalence of the Chlamydia trachomatis in neonatal conjunctivitis determination by indirect fluorescence and gene amplification].

BACKGROUND: Chlamydia trachomatis is one of the most common identifiable infectious agents in neonatal conjunctivitis. It also causes pneumonitis, that is preceded by conjunctivitis in one third of cases. AIM: To asses the prevalence of Chlamydia trachomatis in newborns with conjunctivitis. PATIENTS AND METHODS: In 162 newborns, coming from 14 Primary Health Centers from Santiago de Chile, C. trachomatis was detected by indirect fluorescence and two polymerase chain reaction (PCR 1 and 2), which amplified different sequences from the common endogenous plasmid. Those patients with positive indirect fluorescence and PCR 2 were defined as infected: RESULTS: The prevalence of C. trachomatis was 8%, and the distribution of the positive cases was similar in the different Health Centers. Other isolates were: S. aureus (9.8%), S. pneumoniae (8%), S. viridans (6.2%) y H. influenzae (5.5%). CONCLUSIONS: The prevalence of C. trachomatis in neonatal conjunctivitis in Chile is similar to that of developed countries. Therefore, C. trachomatis should be considered in the election of antimicrobials for the treatment of neonatal conjunctivitis, to avoid ocular and respiratory complications.

Chile↗
PubMed2000

[In vitro comparative activity of moxifloxacin and other antimicrobials against respiratory pathogens].

BACKGROUND: Respiratory pathogens are becoming increasingly resistant to antimicrobials. A new group of drugs, called respiratory quinolones have been synthesized to overcome this problem. AIM: To study the in vitro susceptibility of respiratory pathogens to old and new antimicrobials. MATERIALS AND METHODS: Forty five strains of S pneumoniae, 44 strains of H influenzae, 21 strains of M catarrhalis, 10 strains of methicillin susceptible S aureus and 20 strains of methicillin resistant S aureus were studied. All were isolated from community acquired respiratory infections during 1999. Minimal inhibitory concentrations of moxifloxacin, amoxicillin, amoxicillin/clavulanic acid, clarithromycin, azithromycin, ciprofloxacin and levofloxacin were determined using the Etest method. Beta-lactamase production by H influenzae and M catarrhalis was also studied. RESULTS: S pneumoniae strains were 100% susceptible to quinolones and cotrimoxazole, 2% were resistant to macrolides, 11% were resistant to amoxicillin/clavulanic acid and 47% were resistant to cefuroxime. H influenzae was 100% susceptible to quinolones, azithromycin and amoxicillin/clavulanic acid. There was a 53% resistance to cotrimoxazole, 21% to amoxicillin, 9% to clarithromycin and 7% to cefuroxime. M catarrahalis was 100% susceptible to quinolones and 100% resistant to amoxicillin, 5% resistant to macrolides, 14% resistant to amoxicillin/clavulanic acid, 20% to cefuroxime and 30% to cotrimoxazole. Methicillin susceptible S aureus was susceptible to all antimicrobials and methicillin resistant S aureus was resistant to all. CONCLUSIONS: Maxifloxacin and the new respiratory quinolones can be useful in the treatment of respiratory infections.

Adult↗
PubMed2000

[Prevalence of enterohemorrhagic Escherichia coli in a cattle area of Argentina. Genotypic characterization of the strains of animal origin].

BACKGROUND: There is a high prevalence of infection by Enterohemorrhagic Escherichia coli (EHEC) and patients with hemolytic uremic syndrome (HUS) in Argentina. AIM: To study cattle and pigs as a possible reservoir of EHEC in Argentina. MATERIAL AND METHODS: One hundred two healthy animals (68 cattles and 31 pigs) from a livestock in Argentina, were studied. Stool samples were obtained with a rectal swab. The strains were identified by DNA hybridization with specific gene probes detecting Shiga-like toxin 1 and 2 (Stx1, Stx2), and hly gen related to fimbrial adhesin-associated plasmid. EHEC strains were serogrouped using commercial antisera. RESULTS: EHEC was isolated from 30 out of 68 bovines cultures (44.1%) and from 25 out of 31 pigs (58.1%). Isolates carrying genes codifying both Stx1 and Sxt2, were observed in 50% of cattle and 63.9% of pigs. The gene which codifies for hemolysin (associated to fimbrial adhesin) was observed in about 41% of EHEC isolates. Strains belonging to serogroups O26, O111, and O157 were isolated from cattle, and O111, and O157 from pigs. CONCLUSIONS: The high percentage of EHEC in both cattle and pigs and the presence of human infection-associated serogroups, suggests that these animals are a reservoir of EHEC associated with disease in humans.

Animals↗
PubMed1999

Effect of small bowel bacterial overgrowth on the immunogenicity of single-dose live oral cholera vaccine CVD 103-HgR.

Several live oral vaccines (polio, bovine rotavirus, CVD 103-HgR cholera) are less immunogenic in developing than in industrialized countries. It was hypothesized that proximal small bowel bacterial overgrowth (common in children in less developed countries but rare in industrialized settings) diminishes the vibriocidal antibody response to CVD 103-HgR. In total, 202 fasting Santiago schoolchildren aged 5-9 years had lactulose breath H2 tests to detect proximal small bowel bacteria 1 day before ingesting CVD 103-HgR. Florid small bowel overgrowth was observed in 10 (5.6%) of 178 analyzable children. In children with florid overgrowth, vibriocidal seroconversion differed little from other children (60% vs. 67%), but the geometric mean titer was lower (160 vs. 368; P=.25). By logistic regression, increased peak breath H2 at small bowel time points was associated with diminished seroconversion (P=.04), as was the interaction of H2 value and weight (children >25 kg had lower seroconversion rates among subjects with heaviest overgrowth).

Administration, Oral↗
PubMed1999

Population-based study of the incidence of Shigella diarrhea and causative serotypes in Santiago, Chile.

BACKGROUND: Shigella is an important cause of diarrheal disease in children in developing countries. The increasing prevalence of antibiotic-resistant strains has stimulated interest in the use of multivalent Shigella vaccines. Because Shigella vaccines under development are based on eliciting immunity to O antigens, monitoring the distribution of serotypes in defined target populations is critical. We initiated health center-based surveillance in a poor semirural community in Colina, Santiago (7489 children <60 months of age) to determine the age-specific incidence of Shigella disease and the responsible serotypes. FINDINGS: Surveillance was maintained at the 2 health centers during warm seasons (November 1 through April 30) for 4 successive years (1994 to 1998). Shigella was recovered from 54 of 243 cases of dysentery (22%) and from 215 of 3966 cases of nondysenteric diarrhea (5.4%) (P < 0.001). The peak mean annual incidence of shigellosis occurred among children 12 to 47 months of age (9.0 to 12.6 cases/10(3) children), although the incidence in infants (5.2/10(3)) and children 48 to 59 months of age (6.2/10(3)) was also substantial. During the 1995 through 1996 season, an age-matched healthy control was cultured for every child <60 months of age with diarrhea. Shigella isolation from cases (34 of 576, 5.9%) was >8-fold higher than controls (4 of 576, 0.7%) (P < 0.01). Four serotypes, Shigella sonnei (45%), Shigella flexneri 2b (19%), S. flexneri 2a (14%) and S. flexneri 6 (11%), accounted for 89% of all cases. INTERPRETATION: Shigella remains an important pediatric pathogen in Santiago. The serotype distribution from Colina, which closely resembles data from a population-based surveillance study in Santiago in the mid-1980s, demonstrates a remarkable degree of serotype stability in Santiago during a 15-year period.

Case-Control Studies↗
PubMed1999

Palatability, reactogenicity and immunogenicity of engineered live oral cholera vaccine CVD 103-HgR in Chilean infants and toddlers.

BACKGROUND: Live oral cholera vaccine CVD 103-HgR is well-tolerated and immunogenic when administered to adults, school age children and preschool children in a single 5 x 10(9) colony-forming unit dose. Because elicitation of immune responses after administration of a single dose is exceptional for any oral vaccine in any age group, CVD 103-HgR was used as a probe to investigate the clinical acceptability, practicality and immunogenicity of this vaccine in infants and toddlers 3 to 17 months of age. METHODS: The study was undertaken successively in 12- to 17-month-olds (n = 104), 7- to 11-month-olds (n = 106) and 3- to 5-month-olds (n = 102). One-half of the subjects were randomly allocated to receive vaccine and the other one-half to receive placebo, in double blind fashion. After 2 weeks of double blind follow-up, all subjects received a dose of vaccine. Vibriocidal antibody titers were measured on coded sera collected at baseline and 2 weeks after each dosing. The buffered vaccine "cocktail" had a volume of 100 ml; subjects who ingested > or =70 ml were considered fully vaccinated. FINDINGS: Only 37% of subjects overall (25% of 3- to 5-month-olds) ingested > or =70 ml of the cocktail. The vaccine was well-tolerated with no significant differences in the rate or severity of adverse reactions after ingestion of vaccine vs. placebo. Seroconversion after ingestion of a single dose of CVD 103-HgR was similar in fully vaccinated subjects (66%) and in those who ingested a smaller fraction of the vaccine cocktail (63%). Of subjects who ingested two doses, 5 of 118 excreted vaccine organisms on Day 7 after the first dose vs. 0 of 118 after the second dose. INTERPRETATION: Single dose oral CVD 103-HgR is well-tolerated and immunogenic in infants even when a partial dose is ingested. The buffered vaccine cocktail that is readily imbibed by older children is not appealing to young infants, and improved vaccine formulations and delivery vehicles for immunizing infants must be sought.

Administration, Oral↗
PubMed1999

Genotypic survey of recent beta-lactam-resistant pneumococcal nasopharyngeal isolates from asymptomatic children in Chile.

To assess pneumococcal strain variability among young asymptomatic carriers in Chile, we used serotyping, antibiotic susceptibility testing, and genotyping to analyze 68 multidrug-resistant pneumococcal isolates recovered from 54 asymptomatic children 6 to 48 months of age. The isolates represented capsular serotypes 19F (43 isolates), 14 (14 isolates), 23F (7 isolates), 6B (3 isolates), and 6A (1 isolate). Genotypic analysis, which included pulsed-field gel electrophoresis (PFGE) of chromosomal digests, penicillin binding protein (PBP) gene fingerprinting, and dhf gene fingerprinting, revealed that the isolates represented six different genetic lineages. Clear circumstantial evidence of capsular switching was seen within each of four of the genetically related sets. The majority of the isolates, consisting of the 43 19F isolates and 2 type 6B isolates, appeared to represent a genetically highly related set distinct from previously characterized pneumococcal strains. Each of three other genetically defined lineages was closely related to one of the previously characterized clones Spain(6B)-2, France(9V)-3, or Spain(23F)-1. A fifth lineage was comprised of four type 23F isolates that, by the techniques used for this study, were genetically indistinguishable from three recent type 19F sterile-site isolates from the United States. Finally, a sixth lineage was represented by a single type 23F isolate which had a unique PFGE type and unique PBP and dhf gene fingerprints.

Base Sequence↗
PubMed1999

Clonal diversity of Chilean isolates of enterohemorrhagic Escherichia coli from patients with hemolytic-uremic syndrome, asymptomatic subjects, animal reservoirs, and food products.

To determine clonal relationship among Chilean enterohemorrhagic Escherichia coli (EHEC) strains from different sources (clinical infections, animal reservoirs, and food), 54 EHEC isolates (44 of E. coli O157, 5 of E. coli O111, and 5 of E. coli O26) were characterized for virulence genes by colony blot hybridization and by pulsed-field gel electrophoresis (PFGE). By colony blotting, 12 different genotypes were identified among the 44 E. coli O157 isolates analyzed, of which the genetic profile stx1+ stx2+ hly+ eae+ was the most prevalent. All human O157 strains that were associated with sporadic cases of hemolytic-uremic syndrome (HUS) carried both the stx1 and stx2 toxin-encoding genes and were eaeA positive. Only 9 of 13 isolates from human controls were stx1+ stx2+, and 8 carried the eaeA gene. Comparison of profiles obtained by PFGE of XbaI-digested genomic DNA showed a great diversity among the E. coli O157 isolates, with 37 different profiles among 39 isolates analyzed. Cluster analysis of PFGE profiles showed a wide distribution of clinical isolates obtained from HUS cases and asymptomatic individuals and a clonal relationship among O157 isolates obtained from HUS cases and pigs. Analysis of virulence genes showed that a correlation exists among strains with the genotype stx1+ stx2+ eae+ and pathogenic potential. A larger difference in the PFGE restriction patterns was observed among the EHEC strains of serogroups O26 and O111. These results indicate that several different EHEC clones circulate in Chile and suggest that pigs are an important animal reservoir for human infections by EHEC. Guidelines have been proposed for better practices in the slaughter of animals in Chile.

Animals↗
PubMed1999

[Antimicrobial resistance of agents causing urinary tract infections in 11 Chilean hospitals. PRONARES project].

BACKGROUND: The computer program WHONET generates a common database to analyze local or general antimicrobial resistance of bacteria. A surveillance of agents causing urinary tract infections in Chile has been performed using this program. AIM: To report the results after 12 months of urinary tract infection agent surveillance. MATERIAL AND METHODS: Since November, 1997, a surveillance of in vitro antimicrobial resistance, using agar diffusion techniques, has been performed in 20 to 40 bacterial strains per month, isolated from 11 hospitals in the country. Results have been analyzed using WHONET program. RESULTS: In first 12 months, 3144 strains, 1625 coming from outpatients, have been studied. Seventy four percent of isolated strains were E coli, 19% were other enterobacteria, 4.1% were non fermenting bacilli and 2.1% were Gram (+) cocci. Sixty five percent of E coli strains were resistant to ampicillin, 11% to cefazolin, 2.5% to cefuroxime, 19% to ceftriaxone, 9% to ceftazidime, 4.2% to gentamicin 1.3% to amikacin, 5.6% to ciprofloxacin, 8.4% to grepafloxacin, 4.3% to nitrofurantoin and 43% to trimeproprim/sulphamethoxazole. Eighty two percent of other enterobacteria strains were resistant to ampicillin, 45.5% to cefazolin, 33.5% to cefuroxime, 26.6% to ceftriaxone, 21.5% to ceftazidime, 30.3% to gentamicin 17.2% to amikacin, 21% to ciprofloxacin, 16.3% to grepafloxacin, 48.2% to nitrofurantoin and 44.6% to trimeproprim/sulphamethoxazole. There were differences in betalactamic resistance among hospitals. CONCLUSIONS: Noteworthy is the high resistance rates to third generation cephalosporins, evidenced when the new cutoff values for E coli and Klebsiella spp are used. This national surveillance provides updated information on antimicrobial resistance of agents causing urinary tract infections.

Chile↗
PubMed1999

[Current status of immunity to hepatitis A virus in various adult groups].

BACKGROUND: As sanitary and economic conditions improve, the prevalence of antibodies to hepatitis A is now significantly lower. AIM: To evaluate the prevalence of hepatitis A virus antibodies in healthy Chilean adults. MATERIAL AND METHODS: Antibodies to hepatitis A virus were measured, using a commercial ELISA assay, in 215 voluntary blood donors (163 male, aged 19 to 30 years old) and 295 medical students and health personnel (156 male, aged 19 to 39 years old), residing in Valdivia, Chile. RESULTS: Antibodies against hepatitis A virus were found in 68.2% of the total sample (351/510). Ninety percent of flood donors and 54% of health personnel and students were positive (p < 0.01). Age specific prevalence in blood donors 19 to 22, 23 to 29 and 27 to 30 years old was 81.0%, 95.2% and 95.6% respectively. Among the same age groups in medical students, the prevalence was 47.9%, 53.2% and 61.9% respectively (p < 0.01). CONCLUSIONS: This study indicates a reduction in the prevalence of hepatitis A virus antibodies among adults in Valdivia (Chile). Differences detected between individuals are probably related to different socioeconomic levels. Medical students have an increased risk for hepatitis A infections than the general population.

Adult↗