Dismantling "Race" in Health Research.

In this era of confronting racism in public space, it is critical to keep addressing the covert systemic racism in the healthcare system. We want to bring attention to the continued unscientific practice of race-based medicine and the absurdity of treating race as a biological indicator in the 21st century. We believe race is a social construct that does not qualify as a scientific biological indicator for predicting health outcomes. In this paper, we first present arguments for inappropriate use of race in health research and then discuss alternative explanations for health disparity findings that use race as a predictor. Our main concern centers on two specific aspects of the concept of "race": (1) its fundamental lack of scientific basis as a predictor for health outcomes, (2) the misguided narrative that the term creates, placing the onus of racial discrimination on the victim, instead of highlighting the act of discrimination and the role researchers play in actively reinforcing racism when using "race" as a variable. We conclude by proposing that "race" be replaced by the variable "racism" in health.

Estimating Bordetella pertussis seroprevalence in adolescents and young adults in Mexico using the 2012 National Health and Nutrition Survey (ENSANUT).

BACKGROUND: Low vaccination rates and under-detection of pertussis infections in adolescents and young adults have an impact on the transmission of pertussis to infants. In this study, the proportion of adolescents and young adults with IgG antibodies against B. pertussis antigens, representing recent infection or vaccination, was estimated in a population-based probabilistic survey in Mexico. METHODS: Sera and data from 1,581 subjects, including 1,102 adolescents and 479 young adults (10-19 and 20-25 years old, respectively) randomly selected from Mexico's 2012 National Health and Nutrition Survey, were analyzed. IgG antibodies against pertussis toxin (PT) were measured with the CDC/FDA ELISA. A subset of 234 samples was additionally tested with Bp-IgG PT ELISA kit (EUROIMMUN AG, Lubeck, Germany). Threshold values from corresponding test kits were used to identify recent infection or vaccination. RESULTS: Overall anti-PT IgG seroprevalence was 3.9% (95% CI: 2.3-6.3); 3.1% (95% CI: 1.9-5.0) in adolescents, and 4.9% (95% CI: 2.2-11) in young adults. Seroprevalence did not significantly vary by sex, socioeconomic status, region or rural/urban location. Compared to the CDC/FDA ELISA, the EUROIMMUN test showed a 76% sensitivity and 88% specificity. The weighted estimates represent a considerable burden of recent infection in adolescents and young adults; however, most adolescents and adults were seronegative and, therefore, susceptible to pertussis infection. CONCLUSION: Since booster vaccination to B. pertussis after toddlerhood is not recommended in the Mexican national policy, anti-PT IgG seropositivity may be reasonably attributed to recent infection. Assessing pertussis seroprevalence requires careful consideration of the diagnostic test threshold interpretation and epidemiological model used.

Hypersensitivity in patients receiving metal implants: a scoping review protocol.

OBJECTIVE: The objective of this scoping review is to gather the available evidence on metal hypersensitivity to determine the extent of the problem and identify gaps in the evidence about screening practices. INTRODUCTION: Hypersensitivity to metal was first reported in 1966. Since this time, the use of metal in prosthetic devices has increased with an associated rise in reported hypersensitivity reaction to other metals. Symptoms of metal hypersensitivity can be subtle, and it is unclear whether clinicians are aware of or routinely ask patients about metal hypersensitivity when documenting allergies. This can lead to a delay in diagnosis, which puts patients at risk of poor outcomes. Hence, there is a need to map the available evidence on hypersensitivity reaction in people who receive metallic device implantation. INCLUSION CRITERIA: The review will consider studies that include patients who undergo procedures involving metal implantation. The concept to be explored is hypersensitivity following a procedure that involves the implementation of a device with metal components. Implementation is defined as permanent integration of a foreign (non-biological) object into the human body to restore function. METHODS: The proposed scoping review will be conducted in accordance with JBI methodology for scoping reviews. Searches will be generated in multiple databases and updated as needed. Gray literature and organizational websites will also be searched. Titles, abstracts, and full articles will be screened according to the inclusion criteria. Studies published in English from 1960 to the present will be included. Data will be extracted and findings will be presented in tabular form with a narrative summary.

Análisis de los espectros de absorción de las películas radiocrómicas EBT2 y EBT3 / Analysis of the absorption spectra of EBT2 and EBT3 radiochromic films

Resumen: Objetivo: Analizar los espectros de absorción neta de las películas radiocrómicas EBT2 y EBT3 para describir su influencia en el comportamiento de las curvas de dosis-respuesta. Metodología: Las películas se irradiaron en un acelerador lineal de 6 MV. La obtención de los espectros de absorción neta se realizó con espectrofotómetro UV/VIS. Las curvas de dosis-respuesta se obtuvieron con un escáner, un láser He-Ne y un espectrofotómetro. Resultados: El espectro de absorción de las EBT2 muestra tres bandas de absorción centradas que conservan la posición y aumentan su intensidad en función de la dosis, sin embargo, este comportamiento no se observa en las películas EBT3. La curva dosis-respuesta muestra la máxima sensibilidad utilizando el espectrofotómetro, pero no muestra un comportamiento definido. Implicaciones: Generación de nuevos conocimientos para la creación de nuevos sistemas ópticos capaces de amplificar la sensibilidad de la respuesta de las películas. Originalidad: Mostrar la correlación entre los espectros de absorción neta y su influencia en las curvas dosis-respuesta en tres diferentes sistemas ópticos. Conclusiones: El comportamiento de los espectros de absorción aunado al comportamiento de las curvas dosis-respuesta nos ayuda a descartar el uso de sistemas ópticos que no garanticen un uso clínico confiable.

Abstract: Objective: To analyze the net absorption spectra of EBT2 and EBT3 radiochromic films to describe their influence on the behavior of dose-response curves. Methodology: The films were irradiated in a linear accelerator of 6 MV. The net absorption spectra were obtained with a UV / VIS spectrophotometer. Dose-response curves were obtained with a scanner, a He-Ne laser and a spectrophotometer. Results: The absorption spectrum of the EBT2 shows three focused absorption bands that retain position and increase their intensity as a function of dose, however, this behavior is not observed in EBT3 films. The dose-response curve shows maximum sensitivity using the spectrophotometer, but does not show a defined behavior. Implications: Generation of new knowledge for the creation of new optical systems capable of amplifying the responsiveness of the films. Originality: Show the correlation between net absorption spectra and their influence on dose-response curves in three different optical systems. Conclusions: The behavior of absorption spectra combined with the behavior of the dose-response curves helps to discard the use of optical systems that do not guarantee a reliable clinical use.

Antibiotic pollution in the Katari subcatchment of the Titicaca Lake: Major transformation products and occurrence of resistance genes.

An increasing number of studies pointed out the ubiquitous presence of medical residues in surface and ground water as well as in soil compartments. Not only antibiotics can be found in the environment but also their transformation products about which little information is generally available. The development of bacterial resistance to antibiotics is particularly worrying as it can lead to sanitary and health problems. Studies about the dissemination of antibiotics and associated resistances in the Bolivian Altiplano are scarce. We provide baseline information on the occurrence of Sulfamethoxazole (SMX) and Trimethoprim (TMP) antibiotics as well as on the most common human SMX transformation products (TP) and on the occurrence of sulfonamide resistance genes. The studied water and soil compartments presented high levels of antibiotic pollution. This situation was shown to be mainly linked with uncontrolled discharges of treated and untreated wastewaters, resulting on the presence of antibiotics in the Titicaca Lake. SMX TPs were detected in surface waters and on soil sampled next to the wastewater treatment plant (WWTP). SMX resistance genes sulI and sulII were widely detected in the basin hydrological network, even in areas unpolluted with antibiotics. Mechanisms of co-selection of antibiotic- and metal- resistance may be involved in the prevalence of ARG's in pristine areas with no anthropogenic activity and free of antibiotic pollution.

Typhoid fever acquired in the United States, 1999-2010: epidemiology, microbiology, and use of a space-time scan statistic for outbreak detection.

Although rare, typhoid fever cases acquired in the United States continue to be reported. Detection and investigation of outbreaks in these domestically acquired cases offer opportunities to identify chronic carriers. We searched surveillance and laboratory databases for domestically acquired typhoid fever cases, used a space-time scan statistic to identify clusters, and classified clusters as outbreaks or non-outbreaks. From 1999 to 2010, domestically acquired cases accounted for 18% of 3373 reported typhoid fever cases; their isolates were less often multidrug-resistant (2% vs. 15%) compared to isolates from travel-associated cases. We identified 28 outbreaks and two possible outbreaks within 45 space-time clusters of ⩾2 domestically acquired cases, including three outbreaks involving ⩾2 molecular subtypes. The approach detected seven of the ten outbreaks published in the literature or reported to CDC. Although this approach did not definitively identify any previously unrecognized outbreaks, it showed the potential to detect outbreaks of typhoid fever that may escape detection by routine analysis of surveillance data. Sixteen outbreaks had been linked to a carrier. Every case of typhoid fever acquired in a non-endemic country warrants thorough investigation. Space-time scan statistics, together with shoe-leather epidemiology and molecular subtyping, may improve outbreak detection.

Molecular characterisation of a dominant methicillin-resistant Staphylococcus aureus (MRSA) clone in a Mexican hospital (1999-2003).

Methicillin-resistant Staphylococcus aureus (MRSA) isolates (n = 216), collected between January 1999 and May 2003 in a tertiary-care university hospital in Guadalajara, Mexico, were characterised by antibiotype, pulsed-field gel electrophoresis (PFGE) of SmaI macrorestriction fragments, and hybridisation of ClaI digests with mecA- and Tn554-specific DNA probes. Representatives of the single clonal type found were analysed by spa typing, multilocus sequence typing and staphylococcal chromosomal cassette mec (SCCmec) typing, and were tested for the presence of 22 virulence determinants and agr type. A single PFGE pattern was identified, with minor variations over time, with spa type 2, sequence type 5, SCCmec type II, agr type 2 and the presence of the enterotoxin genes seg and sei, the gamma-haemolysin variant gene hlg-v and the leukocidin lukE-lukD genes. In addition, the isolates showed antimicrobial resistance to beta-lactams, macrolides, chloramphenicol and imipenem, and susceptibility to gentamicin, rifampicin, trimethoprim-sulphamethoxazole and vancomycin. Following its appearance in 1997, this clone spread within the hospital, and is now present in most of the hospital units and wards.

Surveillance of methicillin-resistant Staphylococcus aureus in a pediatric hospital in Mexico City during a 7-year period (1997 to 2003): clonal evolution and impact of infection control.

Between 1997 and 2000 a single multidrug-susceptible methicillin-resistant Staphylococcus aureus clone, M (sequence type 30 [ST30]-staphylococcal cassette chromosome mec [SCCmec] type IV), was present in a pediatric hospital in Mexico City, Mexico. In 2001 the international multidrug-resistant New York-Japan clone (ST5-SCCmec type II) was introduced into the hospital, completely replacing clone M by 2002.

Complete coding sequences of dengue-1 viruses from Paraguay and Argentina.

We have determined the complete coding sequences of six dengue-1 (DEN-1) viruses isolated from Paraguay and Argentina in 2000 from patients with dengue fever. Sequences of strains 259par00, 280par00, 295arg00, 297arg00 and 301arg00 can encode a polyprotein of 3392 amino acids. Strain 293arg00 circulated as a "wild type+deletion mutant" quasispecies, with a subpopulation characterized by a 3-nucleotide deletion in the NS4A region. This variant, which would encode a three amino acid change in the NS4A protein, was found as a minority population in one additional partially-sequenced isolate from the same outbreak. These six South American strains group into two different clades of the "American-African" DEN-1 genotype-one clade is most closely related to strains isolated from Brazil in 1997, the other to a Peruvian strain isolated in 1991 for which only partial sequence information is available. DEN-1 viruses isolated worldwide comprise at least four different genotypes according to previously defined classification criteria.

Phylogenetic relationships of dengue-1 viruses from Argentina and Paraguay.

We sequenced the Capsid-pre Membrane (C/prM) and the Envelope-Nonstructural protein 1 (E/NS1) regions of 24 recent isolates of dengue-1 (DEN-1) from South America. This included 12 Argentinean and 11 Paraguayan DEN-1 strains isolated in 2000 plus a Paraguayan strain isolated in 1988. These sequences were compared with published sequences of DEN-1 isolated worldwide to determine the origin of these isolates. Pairwise comparisons of strains from Paraguay and Argentina revealed a nucleotide divergence of 0-5% in the E/NS1 region and 0-3% in the C/prM region. Our results showed that these viruses belong to the same genotype, but can be separated into two clades. Interestingly, both clades circulated simultaneously in the same geographic area during the 2000 outbreaks. Amino acid differences were found between both clades in the C/prM region at position 100 (Lys vs. Arg) and in the E/NS1 region at positions 722 (Ala vs. Thr). Although the geographic movement of DEN-1 virus can not be unequivocally traced from the genetic relationship determined here, our results suggest that the recent epidemics in Argentina and Paraguay were due to the re-emergence of a previously circulating strain, or to the virus circulating unnoticed, rather than to the introduction of a new genotype.

Evolution of Streptococcus pneumoniae serotypes and penicillin susceptibility in Latin America, Sireva-Vigía Group, 1993 to 1999. PAHO Sireva-Vigía Study Group. Pan American Health Organization.

BACKGROUND: Since 1993 the Pan American Health Organization has coordinated a surveillance network with the National Reference Laboratories of Argentina, Brazil, Chile, Colombia, Mexico and Uruguay aimed at monitoring capsular types and antimicrobial susceptibility of Streptococcus pneumoniae causing invasive disease in children <6 years of age. METHODS: The surveillance system included children 6 years of age and younger with invasive disease caused by S. pneumoniae. The identification, capsular typing and susceptibility to penicillin of the isolates were conducted using a common protocol, based on standard methodologies. RESULTS: By June, 1999, 4,105 invasive pneumococcal isolates had been collected mainly from pneumonia (44.1%) and meningitis (41.1%) cases. Thirteen capsular types accounting for 86.1% of the isolates (14, 6A/6B, 5, 1, 23F, 19F, 18C, 19A, 9V, 7F, 3, 9N and 4) remained the most common types during the surveillance period. Diminished susceptibility to penicillin was detected in 28.6% of the isolates, 17.3% with intermediate and 11.3% with high level resistance. Resistance varied among countries and increased during this period in Argentina, Colombia and Uruguay. Serotypes 14 and 23F accounted for 66.6% of the resistance. CONCLUSION: These surveillance data clearly demonstrate the potential impact of the introduction of a conjugate vaccine on pneumococcal disease and the need for more judicious use of antibiotics to slow or reverse the development of antimicrobial resistance.

[Secondary serologic responses to dengue epidemic in 1998 in Salta, Argentina, where other flavivirus co-circulate]. / Respuestas serológicas secundarias en la epidemia de dengue de 1998 en Salta, Argentina, donde co-circulan otros flavivirus.

In 1998, a dengue outbreak (serotype 2) occurred in Salta province in Northern Argentina, following the first detection of dengue in the same area in 1997. We classified the serologic response of cases from 1998 as primary or secondary, since the risk of severe disease is greater for secondary cases. We studied 154 cases by plaque reduction neutralization and hemagglutination inhibition tests. Thirty-eight cases (25%) were classified as primary serologic responses and 84 cases (54%) as secondary responses. Thirty-two cases (21%) with borderline IgG titers could not be classified. Previous exposure to potentially cross-reacting flaviviruses (Saint Louis Encephalitis [SLE] and Yellow Fever [YF] viruses) was analyzed, as a possible cause of the secondary response pattern. Our results indicated that among cases classified as dengue secondary response, 83% could be attributed to previous SLE or YF exposure or serologic cross-reactivity. Vaccination against YF virus was at most a minor contributor to the secondary response pattern. The finding of a positive YF serologic result among persons not vaccinated may indicate silent circulation of YF in a region that can support both urban and jungle cycles. Other cases showing dengue secondary responses remained unexplained, suggesting the unrecognized occurrence of a previous infection with other dengue serotypes or of flaviviruses other than SLE or YF.

Three-year assessment of methicillin-resistant Staphylococcus aureus clones in Latin America from 1996 to 1998.

Four hundred ninety-nine methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered from 1996 to 1998 from 22 hospitals in five countries of Latin America-Argentina, Brazil, Chile, Uruguay and Mexico-were examined for antimicrobial susceptibility and clonal type in order to define the endemic clones in those hospitals. The hybridization of ClaI restriction digests with the mecA- and Tn554-specific DNA probes combined with pulsed-field gel electrophoresis of chromosomal SmaI digests (ClaI-mecA::ClaI-Tn554::PFGE clonal types) documented not only the predominance and persistence of the Brazilian clone (XI::B::B) in Brazil (97%) and Argentina (86%) but also its massive dissemination to Uruguay (100%). Moreover, a close relative of the Brazilian clone (XI::kappa::B) was highly represented in Chile (53%) together with a novel clone (47%) (II::E'::F) resistant to pencillin, oxacillin, ciprofloxacin, chloramphenicol, clindamycin, erythromycin, and gentamicin. A unique clonal type (I::NH::M) was detected in Mexico among pediatric isolates and was resistant to penicillin, oxacillin, and gentamicin only. This study clearly documented the very large capacity for geographic expansion and the persistence of the Brazilian clone, contributing not only to the increasing uniformity of the MRSA in South America but worldwide as well.

Respuestas serológicas secundarias en la epidemia de dengue de 1998 en Salta, Argentina, donde co-circulan otros flavivirus. / [Secondary serologic responses to dengue epidemic in 1998 in Salta, Argentina, where other flavivirus co-circulate]

In 1998, a dengue outbreak (serotype 2) occurred in Salta province in Northern Argentina, following the first detection of dengue in the same area in 1997. We classified the serologic response of cases from 1998 as primary or secondary, since the risk of severe disease is greater for secondary cases. We studied 154 cases by plaque reduction neutralization and hemagglutination inhibition tests. Thirty-eight cases (25

) were classified as primary serologic responses and 84 cases (54

) as secondary responses. Thirty-two cases (21

) with borderline IgG titers could not be classified. Previous exposure to potentially cross-reacting flaviviruses (Saint Louis Encephalitis [SLE] and Yellow Fever [YF] viruses) was analyzed, as a possible cause of the secondary response pattern. Our results indicated that among cases classified as dengue secondary response, 83

could be attributed to previous SLE or YF exposure or serologic cross-reactivity. Vaccination against YF virus was at most a minor contributor to the secondary response pattern. The finding of a positive YF serologic result among persons not vaccinated may indicate silent circulation of YF in a region that can support both urban and jungle cycles. Other cases showing dengue secondary responses remained unexplained, suggesting the unrecognized occurrence of a previous infection with other dengue serotypes or of flaviviruses other than SLE or YF.

Allozymic polymorphism in Aedes aegypti populations from Argentina.

In Argentina, reinfestation with Aedes aegypti was registered in 1986. At present, the mosquito is well established in 10 provinces, from Buenos Aires up to the country's northern frontiers. This paper presents estimates of genetic variability in Ae. aegypti populations from central Argentina and determinations of genetic distances among them. We analyzed allozymic frequencies at 11 loci in samples from 3 localities. The proportion of polymorphic loci varied between 27.3 and 63.6. Expected mean heterozygosity ranged from 0.090 to 0.161 and Rogers' similarity among samples ranged between 0.909 and 0.958. The lack of relationship between genetic and geographic distances is in agreement with a recent colonization of the studied area. The mean Wright's coefficient FST value (0.065) indicates low levels of genetic differentiation among populations from different localities. Given the recent reinfestation with this mosquito in Argentina, the high levels of polymorphism found could indicate multiple introductions of representative samples from genetically different subpopulations.

Prenatal diagnosis of solid placental masses: the value of color flow imaging.

OBJECTIVES: To determine the value of color flow imaging in the prenatal differentiation of solid placental masses protruding from the fetal surface of the placenta. METHODS: Seven pregnancies in which a large solid mass was seen on the fetal surface of the placenta were prospectively studied. Color flow imaging was used to identify vessels within the mass and the prenatal ultrasound finding correlated with placental pathology. RESULTS: Postpartum examination of the placenta revealed four cases of chorioangioma, two cases of subchorionic thrombohematoma and one case of subamniotic hematoma. Prenatal ultrasound using color flow imaging correctly identified all cases of placental chorioangioma by the demonstration of blood flow within the mass. Conversely, absence of blood flow signals was invariably documented in both cases of subchorionic thrombohematoma and in the single case of subamniotic hematoma. Among the four cases of chorioangioma, two developed complications requiring delivery. No complications were noted in cases of avascular placental masses in this series. CONCLUSIONS: Color Doppler ultrasound plays an important role in the prenatal evaluation of solid placental masses. This technique allows the identification of those cases at increased risk of pregnancy complications which need close monitoring throughout gestation.

[Outbreak of Dengue-2 virus in Salta, Argentina, 1988]. / Epidemia por virus dengue-2 en Salta, Argentina, 1998.

Dengue (DEN) reemergence was first detected in Salta, Argentina, in 1997. It was confirmed by serology and PCR that DEN-2 virus was responsible for sporadic cases and indigenous transmission. A laboratory-based surveillance system allowed the detection of an outbreak in Salta several months later. In total, 378 DEN cases were laboratory diagnosed out of 646 (58%) studied. The cases were distributed in 10 localities of the province between January 3rd and May 31st, 1998. One DEN-2 viral isolation and 4 PCR products were obtained from patients coming from Orán and Embarcación localities. Male and female cases occurred at a similar rate (1:1), with adult cases (82.5%) nearly five times greater than for children under 15 years-old (17.5%). Clinically, all cases corresponded to classic DEN. This is the first time that a DEN outbreak has been laboratory-diagnosed in Argentina and also the first time that DEN virus has been isolated in this country.