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Epidemiology of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome in injection drug users in Argentina: high seroprevalence of HIV infection.

The aim of this study was to compile published data and to describe the prevalences of human immunodeficiency virus (HIV) infection among injection drug users (IDUs) in different populations studied in Argentina from 1987 through 1999. Twenty-two studies of HIV infection in the IDU population were selected, and 6 subject groups were defined: outpatients, prisoners, children in rehabilitation institutes, hospitalized patients, IDUs receiving drug treatment, and female sex workers. The median prevalence of HIV infection among 1506 outpatients (5 studies) was 64.0%; among 175 prisoners (1 study), the prevalence was 35.4%; among 446 children in rehabilitation institutes (4 studies), the prevalence was 48.1%; among 136 hospitalized patients (2 studies), the prevalence was 49.5%; among 2708 IDUs receiving drug treatment (7 studies), the prevalence was 39.0%; and among 26 female sex workers (2 studies), the prevalence was 47.0%. Prevalence of HIV infection was high among IDUs in Argentina, ranging from 27% to 80%.

Argentina↗

Drug use, harm reduction, and health policies in Argentina: obstacles and new perspectives.

High human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) incidence among injection drug users (IDUs) shows the failure of traditional health policies. The preference of IDUs for injected cocaine exposes them to high risks for contracting HIV because of the frequency of drug use. The correlation of poverty with the selling of drugs, especially the so-called "drugs of poverty"--freebase cocaine and crack--is a consequence of prohibitions against drug use and of urban unemployment. In Argentina, "zero-tolerance" approaches and punishment for personal drug use tend to exclude IDUs from the country's health care system. A historical perspective is presented regarding approaches to the prevention of HIV/AIDS and harm reduction in Latin America and Argentina, where, despite isolated efforts, IDUs had no free access to sterile needles until the end of the 1990s. We present the impact of programs and campaigns of the Argentinean Harm Reduction Association, showing how and why, even with obstacles, harm reduction is possible and necessary.

Anti-HIV Agents↗

Device-associated nosocomial infection rates in intensive care units of Argentina.

BACKGROUND: Nosocomial infections are an important public health problem in many developing countries, particularly in the intensive care unit (ICU) setting. No previous data are available on the incidence of device-associated nosocomial infections in different types of ICUs in Argentina. METHODS: We performed a prospective nosocomial infection surveillance study during the first year of an infection control program in six Argentinean ICUs. Nosocomial infections were identified using the Centers for Disease Control and Prevention National Nosocomial Infections Surveillance System definitions, and site-specific nosocomial infection rates were calculated. RESULTS: The rate of catheter-associated bloodstream infections in medical-surgical ICUs was 30.3 per 1,000 device-days; it was 14.2 per 1,000 device-days in coronary care units (CCUs). The rate of ventilator-associated pneumonia in medical-surgical ICUs was 46.3 per 1,000 device-days; it was 45.5 per 1,000 device-days in CCUs. The rate of symptomatic catheter-associated urinary tract infections in medical-surgical ICUs was 18.5 per 1,000 device-days; it was 12.1 per 1,000 device-days in CCUs. CONCLUSION: The high rate of nosocomial infections in Argentinean ICUs found during our surveillance suggests that ongoing targeted surveillance and implementation of proven infection control strategies is needed in developing countries such as Argentina.

Argentina↗

Genetic diversity and epidemiology of hantaviruses in Argentina.

Phylogenetic analysis of a 292-nucleotide (nt) fragment of the hantavirus M genome segment from 36 rodent and 13 human samples from three known foci of hantavirus infection in Argentina was conducted. A 1654-nt fragment of the M genome segment was analyzed for 1 representative of 7 genetically distinct hantavirus lineages identified. Additionally, the nt sequence of the complete M genome segments of Lechiguanas, Oran, and Hu39694 hantavirus genotypes was determined. nt sequence comparisons reveal that 7 hantavirus lineages from Argentina differ from each other by 11.5%-21.8% and from Sin Nombre, Bayou, and Black Creek Canal viruses by 23.8%-26.5%. Phylogenetic analyses demonstrate that they form a unique, separate branch within the clade containing other New World sigmodontine-borne hantaviruses. Most Oligoryzomys-borne hantavirus genotypes clearly map together. The Oligoryzomys-borne genotypes Lechiguanas, Oran, and Andes appear to be associated with human disease. Oligoryzomys longicaudatus was identified as the likely rodent reservoir for Andes virus.

Animals↗

Evidence of a high frequency of HIV-1 subtype F infections in a heterosexual population in Buenos Aires, Argentina.

We analyzed HIV-1 genetic variability, phylogenetic relationships, and association with transmission modes among 58 HIV-1-infected patients from Buenos Aires City, Argentina. The 58 strains were classified as env(gp41) HIV-1 group M subtype B (n = 34) and subgroup F1 of subtype F (n = 24). Potential recombinants combining parts of viral regions from different subtypes, B(prot)/F(env) and F(prot)/B(env), were found in two patients, and a dual infection with HIV-1 prot subtypes B and F was identified in one individual. Epidemiologic analysis of behavioral risks revealed that the frequency of infection with subtype F viruses was significantly higher (p < 0.0001) among heterosexual patients (71%) compared with homosexual patients (11%). The spread of non-B subtypes into heterosexual populations may be more common than previously thought. Our findings provide important information for monitoring the transmission of HIV-1 strains among different risk groups in Argentina as well as for vaccine development.

Adult↗

Mother-to-child HIV type 1 transmission in Argentina: BF recombinants have predominated in infected children since the mid-1980s.

The molecular epidemiology of HIV-1 in Argentina is more complex than was previously appreciated. One circulating recombinant form, CRF12_BF, and many related BF recombinant forms predominate in the capital city, Buenos Aires. This study of HIV-1 subtypes acquired perinatally between 1984 and 2000 has permitted, for the first time, a reconstruction of the history of BF recombination in Argentina. Sequencing of a partial genome region from the beginning of vpu to the beginning of env(gp120), which spans a breakpoint common in most contemporary Argentine BF recombinants, enabled samples to be rapidly screened. Among 23 children born between 1984 and 2000, 15 including 1 child born in 1986, harbored a BF recombinant. Thirteen of the 15 recombinants shared a common breakpoint at the 5' end of env(gp120). Full genome sequencing of two viruses, from 1986 and 1987, respectively, revealed them to be genetically related but not identical to CRF12_BF. Both contained more subtype B sequence than did CRF12_BF. BF recombinants related to CRF12_BF have been in circulation in Buenos Aires since 1986 and continue to predominate in perinatal transmissions.

Adolescent↗

Documentation of subtype C HIV Type 1 strains in Argentina, Paraguay, and Uruguay.

HIV subtypes B, F, and BF recombinants have been previously reported in South America. This report describes the presence of HIV-1 subtype C infection in the countries of Argentina, Uruguay, and Paraguay dating back to at least 1999. Surveillance for uncommon non-B/non-F subtype viruses circulating in South America has been conducted in samples obtained from nine countries. Peripheral blood mononuclear cells (PBMC), dried filter paper (FP), and fresh blood (FB) samples were collected from HIV-positive patients from Ecuador, Colombia, Venezuela, Peru, Chile, Bolivia, Argentina, Uruguay, and Paraguay. From a total of 2962 HIV seropositive samples examined during a 9-year period (1995-2003), only 11 (0.4%) were found to be infected with non-B/non-F HIV variants. Eight of these 11 strains were determined to be subtype C by heteroduplex mobility assay (HMA). Five of these 8 strains were further characterized by sequencing and phylogenetic analysis of the protease (Pro) and reverse transcriptase (RT) region of the genome and two were sequenced full length. One of the strains was found to be a unique BC recombinant. The spread of a third subtype of HIV, subtype C, should raise the question of its potential future role in the HIV epidemic in this region.

Adult↗

Circulation of novel HIV type 1 A, B/C, and F subtypes in Argentina.

The Argentine HIV-1 epidemic is considered to be represented mainly by subtype B and diverse B/F recombinants, with apparent absence of pure subtype F. In this study we describe three novel HIV-1 variants isolated from four infants born in different and distant provinces of Argentina. Partial analysis of different gene fragments spanning 18.5-40.8% of the HIV-1 complete genome revealed two subtype A HIV-1 strains in siblings, a B/C recombinant with a novel mosaic structure, and a putative subtype F. Characteristic patterns of genomic and amino acid sequences of the newly reported subtype F isolate suggest a closer genetic relationship to Argentine B/F recombinants than any other subtype F strain described so far, while the A and B/C subtypes found correspond to unusual genotypes in Argentina. Understanding the origin, diversity, and spread of HIV-1 strains worldwide will be necessary for the development of an effective vaccine approach.

Amino Acid Sequence↗

Characterization and epidemiologic subtyping of Shiga toxin-producing Escherichia coli strains isolated from hemolytic uremic syndrome and diarrhea cases in Argentina.

Argentina has a high incidence of hemolytic uremic syndrome (HUS); 12.2 cases per 100,000 children younger than 5 years old were reported in 2002. Shiga toxin (Stx)-producing Escherichia coli (STEC) is the primary etiologic agent of HUS, and STEC O157 is the predominant serogroup isolated. The main objective of the present work was to establish the phenotypic and genotypic characteristics of the STEC strains in general isolated from Argentine children during a prospective study and the clonal relatedness of STEC O157:H7 strains using subtyping techniques. One hundred and three STEC strains isolated from 99 children were included. The phenotypic and genotypic features were established, and a polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) was performed to determine stx2 variants. The clonal relatedness of E. coli O157 isolates was established by phage typing and pulsed-field gel electrophoresis (PFGE). The 103 STEC strains belonged to 18 different serotypes, and 59% were of serotype O157:H7. Stx2 was identified in 90.3%, and stx1 in 9.7%. Among the 61 STEC O157 strains, 93.4% harbored the stx2/stx2vh-a genes; PT4 (39.3%) and PT2 (29.5%) were the predominant phage types. Using PFGE with the enzyme XbaI, a total of 41 patterns with at least 80% similarity were identified, and seven clusters with identical profiles were established. Some of the clusters were further split by PFGE using BlnI as the second enzyme. Isolates with indistinguishable PFGE patterns were with one exception also indistinguishable by phage typing and stx genotyping. These findings confirmed that some isolates were genetically related. However, no epidemiological linkages were identified. STEC strains with different genotypes and belonging to diverse serotypes were isolated in Argentina. Some STEC O157 strains could not be distinguished by applying subtyping techniques such as PFGE and phage typing.

Argentina↗

Penicillin-resistant Streptococcus pneumoniae in Argentina: frequent occurrence of an internationally spread serotype 14 clone.

Six Latin-American countries participated in an epidemiological surveillance study conducted by the Pan American Health Organization in order to determine the relative prevalence of capsular types and antimicrobial resistance patterns of Streptococcus pneumoniae (SPN) causing invasive infections in children <5 years of age. In Argentina, the incidence of penicillin resistance (PR) was 24.4%, and it was significantly associated with serotype 14 (p < 0.001). The chromosomal DNA of 56 of those SPN isolates, 39 PR and 17 susceptible, was digested with SmaI and resolved by PFGE. Eighty-two percent (32/39) of the PR isolates shared characteristics with the widely spread International Spanish/French clone (clone B). All members of clone B except one expressed serotype 14, with the exception of one isolate that expressed serotype 19F and probably resulted from an in vivo capsular transformation event. Only a single isolate shared features with the 23F International Spanish/USA clone (clone A). The 17 penicillin-susceptible (PS) SPN isolates presented an enormous degree of variation in the chromosomal background, expressing 12 serotypes and 13 PFGE patterns. The data suggest that over 80% of the SPN-PR isolates in Argentina were imported, and this confirms the importance of the geographic spread of SPN clones in South America.

Argentina↗

Phytolith assemblages in grasses native to central Argentina.

BACKGROUND AND AIMS: Phytolith reference collections are a prerequisite for accurate interpretation of soil phytolith assemblages aimed at reconstructing past vegetation. In this study a phytolith reference collection has been developed for several grasses native to central Argentina: Poa ligularis, Piptochaetium napostaense, Stipa clarazii, Stipa tenuis, Stipa tenuissima, Stipa eriostachya, Stipa ambigua, Stipa brachychaeta, Pappophorum subbulbosum, Digitaria californica, Bothriochloa edwardsiana and Aristida subulata. METHODS: For each species, phytoliths present in the leaf blades were classified into 47 morphotypes, and their relative frequency determined by observing 300-400 phytoliths per sample (n = 5). Data were analyzed by complete linkage cluster analysis, using the Morisita Index as measure of association. KEY RESULTS: The results showed differentiation among phytolith assemblages at species level or at plant functional type level. Cluster analysis separated C3 from C4 species and palatable from non-palatable species. CONCLUSIONS: This study highlights the possibility of reconstructing past vegetation in central Argentina grasslands through the analysis of soil phytolith assemblages.

Argentina↗

Reforming health insurance in Argentina and Chile.

The paper examines the recent reforms of health insurance in Chile and Argentina. These partially replace social health insurance with individual insurance administered through the private sector. In Chile, reforms in the early 1980s allowed private health insurance funds to compete for affiliates with the social health insurance system. In Argentina, reforms in the 1990s aim to open up the union-administered social insurance system to competition both internally and from private insurers. The paper outlines the specific articulation of social and individual health insurance produced by these reforms, and discusses the implications for health insurance coverage, inequalities in access to healthcare, and health expenditures.

Adolescent↗

Improving access to pharmaceuticals in Brazil and Argentina.

The population of many Latin American countries is having increasing difficulty in accessing needed medicines due to the rise in their unitary cost and the growing number of poor in most countries of the region. A number of countries have taken steps to increase access to pharmaceuticals and have had different levels of success. This article reports on two country-wide programmes: the AIDS programme in Brazil, which has been judged as being highly successful, and the Remediar programme that has been implemented recently in Argentina. Both programmes have significantly increased access to needed pharmaceuticals, and Argentina has done it in a record time. In the discussion, we suggest that pharmaceutical interventions are successful when there is a firm political commitment, they are comprehensive, include the participation of civil society, and use a combination of methods to control the rising cost of medicines, including centralized international competitive bidding processes for drug procurement and reliance on multi-source drugs.

Argentina↗

Geographical patterns of cancer mortality in Argentina.

Mortality rates in 1980, for the major cancer sites, are presented for Argentina as a whole, and for the 22 provinces, the capital city, and the southern territories. In comparison with other countries, national mortality rates are high for oesophageal cancer and cancer of the larynx, and moderately elevated for cancers of the lung, colon, breast, and bladder in males. The rates of tobacco-related cancers (lung, bladder and larynx) were much higher in males than females, and in males showed similar geographical patterns. In females, breast cancer rates by province showed a positive correlation with those for cancer of the colon, and a negative correlation with cervical cancer. There were marked geographical variations, quite different in the two sexes, in the mortality from oesophageal cancer. It is suggested that, although some of these variations within Argentina may be related to ethnic differences and patterns of migration from neighbouring countries, for the majority the explanations must lie in different exposures to environmental of lifestyle factors, such as diet.

Argentina↗

Lung and kidney cancer mortality associated with arsenic in drinking water in Córdoba, Argentina.

BACKGROUND: Studies in Taiwan have found dose-response relations between arsenic ingestion from drinking water and cancers of the skin, bladder, lung, kidney and liver. To investigate these associations in another population, we conducted a study in Córdoba, Argentina, which has a well-documented history of arsenic exposure from drinking water. METHODS: Mortality from lung, kidney, liver and skin cancers during the period 1986-1991 in Córdoba's 26 counties was investigated, expanding the authors' previous analysis of bladder cancer in the province. Counties were grouped a priori into low, medium and high arsenic exposure categories based on available data. Standardized mortality ratios (SMR) were calculated using all of Argentina as the reference population. RESULTS: We found increasing trends for kidney and lung cancer mortality with arsenic exposure, with the following SMR, for men and women respectively: kidney cancer, 0.87, 1.33, 1.57 and 1.00, 1.36, 1.81; lung cancer, 0.92, 1.54, 1.77 and 1.24, 1.34, 2.16 (in all cases, P < 0.001 in trend test), similar to the previously reported bladder cancer results (0.80, 1.28, 2.14 for men, 1.22, 1.39, 1.81 for women). There was a small positive trend for liver cancer but mortality was increased in all three exposure groups. Skin cancer mortality was elevated for women only in the high exposure group, while men showed a puzzling increase in mortality in the low exposure group. CONCLUSIONS: The results add to the evidence that arsenic ingestion increases the risk of lung and kidney cancers. In this study, the association between arsenic and mortality from liver and skin cancers was not clear.

Argentina↗

Native and introduced host plants of Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae) in northwestern Argentina.

Wild or commercially grown, native and exotic fruit were collected in 30 localities in the Tucumán province (NW Argentina) from January 1990 to December 1995 to determine their status as hosts of Anastrepha fraterculus (Wiedemann) and/or Ceratitis capitata (Wiedemann), the only two fruit fly species of economic and quarantine importance in Argentina. A total of 84,094 fruit (3,466.1 kg) representing 33 species (7 native and 26 exotic) in 15 plant families were sampled. We determined the following 17 host plant associations: Annona cherimola Miller (Annonaceae), Citrus paradisi Macfadyn (Rutaceae), Diospyros kaki L. (Ebenaceae), Eugenia uniflora L., Psidium guajava L., Myrcianthes pungens (Berg) Legrand (Myrtaceae), Ficus carica L. (Moraceae), Juglans australis Grisebach (Juglandaceae), Mangifera indica L. (Anacardiaceae), Eriobotrya japonica (Thunb.) Lindl., Prunus armeniaca L., P. domestica L., and P. persica (L.) Batsch (Rosaceae) were infested by both A. fraterculus and C. capitata. Citrus aurantium L., Citrus reticulata Blanco, Citrus sinensis (L.) Osbeck (Rutaceae), and Passiflora caerulea L. (Passifloraceae) were only infested by Ceratitis capitata. Out of a total of 99,627 adults that emerged from pupae, 69,180 (approximately 69.5%) were Anastrepha fraterculus, 30,138 (approximately 30.2%) were C. capitata, and 309 (approximately 0.3%) were an unidentified Anastrepha species. Anastrepha fraterculus predominated in native plant species while C. capitata did so in introduced species. Infestation rates (number of larvae/kg of fruit) varied sharply from year to year and between host plant species (overall there was a significant negative correlation between fruit size and infestation level). We provide information on fruiting phenology of all the reported hosts and discuss our findings in light of their practical (e.g., management of A. fraterculus and C. capitata in citrus groves) implications.

Animals↗

Culex species (Diptera: Culicidae) from central Argentina: identification by electrophoretic zymograms and genetic relationships.

Starch gel electrophoretic zymograms were used for the taxonomic separation of mosquitoes of the genus Culex, possible vectors of encephalitis in Argentina. Catalase, hexokinase, malic enzyme, isocitrate and malate dehydrogenases, and leucine aminopeptidase were species markers that allowed the clear identification of individual Culex apicinus Philippi, Cx. bidens Dyar, Cx. brethesi Dyar, Cx. declarator Dyar and Knab, Cx. dolosus Arribalzaga, Cx. maxi Dyar, Cx. quinquefasciatus Say, Cx. saltanensis Dyar, and Cx. tatoi Casal & García. Intraspecific polymorphism was revealed but did not preclude species separation. On the basis of allele frequencies, an index of genetic distance between species was calculated. Genetic affinities determined by electrophoretic data agreed with taxonomic affinities ascertained by conventional systematics. Thus, electrophoretic zymograms proved to be a powerful tool for the study of the genus Culex in Argentina.

Alleles↗

Genetic structure of Aedes albifasciatus (Diptera: Culicidae) populations in central Argentina determined by random amplified polymorphic DNA-polymerase chain reaction markers.

The floodwater mosquito, Aedes albifasciatus (Macquart), is the main vector of western equine encephalomyelitis virus in Argentina. Previous studies on the genetic structure of this species using allozymes showed low levels of polymorphism, absence of subpopulations at distinct habitats, and moderate differentiation among localities separated up to 500 km. To examine gene flow using other genetic methods, we analyzed random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) polymorphism in 28 presumptive loci of Ae. albifasciatus from 6 populations in central Argentina. Allele frequencies were estimated assuming that RAPD products segregate as dominants and that genotype frequencies at those loci are in Hardy-Weinberg equilibrium. Expected heterozygosity ranged between 0.19 and 0.31, approximately 3 times the value obtained on the basis of the 16 allozymic loci studied previously. Four of the populations formed a single panmictic unit. Allele frequencies in populations occupying different phytogeographic regions gave significant FST values at 5 loci. Effective migration rates among populations estimated from FST ranged from 2.3 to 9.0. The results support the existence of a north-south cline.

Aedes↗