To reduce influenza-associated morbidity and mortality, countries in South America recommend annual influenza vaccination for persons at high risk for severe influenza illness, including young children, persons with preexisting health conditions, and older adults. Interim estimates of influenza vaccine effectiveness (VE) from Southern Hemisphere countries can provide early information about the protective effects of vaccination and help guide Northern Hemisphere countries in advance of their season. Using data from a multicountry network, investigators estimated interim VE against influenza-associated severe acute respiratory illness (SARI) hospitalization using a test-negative case-control design. During March 13-July 19, 2024, Argentina, Brazil, Chile, Paraguay, and Uruguay identified 11,751 influenza-associated SARI cases; on average, 21.3% of patients were vaccinated against influenza, and the adjusted VE against hospitalization was 34.5%. The adjusted VE against the predominating subtype A(H3N2) was 36.5% and against A(H1N1)pdm09 was 37.1%. These interim VE estimates suggest that although the proportion of hospitalized patients who were vaccinated was modest, vaccination with the Southern Hemisphere influenza vaccine significantly lowered the risk for hospitalization. Northern Hemisphere countries should, therefore, anticipate the need for robust influenza vaccination campaigns and early antiviral treatment to achieve optimal protection against influenza-associated complications.

BACKGROUND: Vaccine effectiveness (VE) is essential to monitor the performance of vaccines and generate strategic information to guide decision making. We pooled data from six Latin American countries to estimate the effectiveness of COVID-19 vaccines in preventing laboratory-confirmed SARS-CoV-2 hospitalisation during three different pandemic waves from February 2021 to September 2022. METHODS: We used a test-negative case-control design in hospitalised adults in Chile, Costa Rica, Ecuador, Guatemala, Paraguay, and Uruguay. We estimated adjusted VE by age group (18-64 and ≥65 years), vaccine type and product for primary series vaccination and booster vaccination and by time since last dose during the Omicron variant dominant period. We used mixed effects logistic regression models adjusting for sex, age, week of onset of symptom onset and pre-existing conditions with country fit as a random effect term. FINDINGS: We included 15,241 severe acute respiratory infection (SARI) patients in the analysis. Among adults 18-64 years, VE estimates for primary series vaccination during pre-Delta and Delta periods ranged by product from 66.5% to 95.1% and from 33.5% to 88.2% for older adults. During the Omicron period, VE estimates for primary series were lower and decreased by time since last vaccination, but VE increased to between 26.4% and 57.4% when a booster was administered. INTERPRETATION: mRNA and viral vector vaccines presented higher VE for both primary series and booster. While VE decreased over time, protection against severe COVID-19-associated hospitalisation increased when booster doses were administered. Vaccination with additional doses should be recommended, particularly for persons at increased risk of developing severe COVID-19. FUNDING: This work was supported by a grant from the U.S. Centers for Disease Control and Prevention (CDC) through cooperative agreements with the Pan American Health Organization/World Health Organization.

What is already known about this topic? | | Effectiveness of seasonal influenza vaccine varies by season and circulating virus type. | | What is added by this report? | | The 2023 Southern Hemisphere seasonal influenza vaccine reduced the risk for influenza-associated hospitalizations by 52%. Circulating influenza viruses were genetically similar to those targeted by the 2023–24 Northern Hemisphere influenza vaccine formulation. This vaccine might offer similar protection if these viruses predominate during the coming Northern Hemisphere influenza season. | | What are the implications for public health practice? | | Vaccination remains one of the most effective ways to protect against influenza-associated complications. In anticipation of Northern Hemisphere influenza virus circulation, CDC recommends that health authorities encourage U.S. health care providers to administer seasonal influenza vaccine to all eligible persons aged ≥6 months.

Abstract We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for “Unity-aligned” First Few X cases (FFX) and HHTIs published 1 December 2019 to 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases; 16 provided by Unity Studies collaborators) were retained in the systematic review; 62 were included in the primary meta-analysis. hSAR point estimates ranged from 2% to 90% (95% prediction interval: 3%–71%; I2 = 99.7%); I2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses.

We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for 'Unity-aligned' First Few X cases (FFX) and HHTIs published between 1 December 2019 and 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases; 16 provided by Unity Studies collaborators) were retained in the systematic review and 62 were included in the primary meta-analysis. hSAR point estimates ranged from 2%-90% (95% prediction interval: 3%-71%; I2=99.7%); I2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license.

The adult stage is the only nonaquatic stage of the Anopheles mosquito. Both male and female Anopheles mosquitoes require access to a source of sugar to survive. In the insectary, a temperature of ∼27°C and 80% relative humidity and a cycle of 12 h light:12 h dark light, ideally with a sunrise and sunset period, are necessary minimum conditions to mimic their natural environment. Laboratory-reared Anopheles can survive for over a month; however, decreased activity and increased mortality may be observed ∼2 wk postemergence depending on the species and health of the colony. Details on how to maintain adults Anopheles are discussed here. Information and considerations on blood and sugar feeding are described. This protocol also provides instructions on how to differentiate male and female adult mosquitoes.

Mosquito larvae are aquatic and go through four development stages (larval instars L1-L4) before pupation. Species vary in the duration of larval development, and a variety of external factors affect the development rate (e.g., water temperature, food type, and larval density), which are discussed more thoroughly elsewhere. Here, we detail how to rear Anopheles larvae. This protocol describes appropriate distribution of larvae into rearing pans, feeding of larvae, cleaning of pans, and care until pupation.

Anopheles mosquitoes can transmit several human pathogens, including viruses such as o'nyong-nyong and parasites including Plasmodium spp. and Wuchereria spp., which cause malaria and filariasis, respectively. Rearing Anopheles species of medical importance under laboratory conditions allows researchers to carry out experiments to better understand their genetics, physiology, and behavior. However, Anopheles species vary in how easily they can be reared in the laboratory, and some species have been difficult to colonize. Once established, members of the important African Anopheles gambiae complex thrive following a standard protocol and are predictable in growth and development rates. Here, we provide useful basic information and guidance to successfully maintain colonies of A. gambiae and other species of Anopheles in a laboratory setting. We also provide an example of a 3-wk rearing schedule that produces sufficient numbers of mosquitoes while minimizing the work required during weekends. In the accompanying protocols, we detail efficient methods and techniques suitable for several species of this genus at the egg, larva, pupae, and adult stages; however, it will be necessary for researchers to adjust methods as needed based on site-specific rearing observations of their particular strains.

Gravid (i.e., with fully developed eggs), mated Anopheles females typically lay their eggs directly on water ∼48-72 h after a blood meal. Unlike some other mosquito species, Anopheles eggs cannot be desiccated and stored for long durations, and, hence, colonies must be reared continuously. In this protocol, we discuss methods for egg collection, including individual and en masse oviposition; egg disinfection to avoid the transmission of infectious agents to the next generation; and egg hatching for colony maintenance or experimentation. We also include optional methods for estimating life history traits such as fecundity, fertility, and larval mortality rates from egg counts.

For most Anopheles species, larval-pupal metamorphosis commences ∼1 wk after egg hatching. However, depending on the amount of food provided, H(2)O temperature, and larval density, the pupation process can be accelerated or delayed. Synchronous pupation is difficult to accomplish consistently, and, thus, pupae need to be separated from larvae daily. Adult emergence will take place 24-48 h after pupation. Most adults will eclose before the next morning (light cycle) in many species. Here, we provide information on some methods available to collect pupae and to sort pupae by sex. Notably, pupa collection and sorting are some of the most time-consuming procedures of the overall mosquito rearing process. Some methods mentioned here attempt to help reduce work effort and time required.

Global sequencing and surveillance capacity for SARS-CoV-2 must be strengthened and combined with multidisciplinary studies of infectivity, virulence and immune escape, in order to track the unpredictable evolution of the ongoing COVID-19 pandemic. | | In June 2020, the World Health Organization (WHO) SARS-CoV-2 evolution working group was established to track SARS-CoV-2 variants and their specific genetic changes and to monitor viral characteristics and their impact on medical and non-medical countermeasures, including vaccines against COVID-19. In November 2021, this working group transitioned to a formal WHO Technical Advisory Group on Virus Evolution (TAG-VE), with the aim of developing and implementing a global risk-monitoring framework for SARS-CoV-2 variants, based on a multidisciplinary approach that includes in silico, virological, clinical and epidemiological data.

Background: External quality assessments (EQAs) for the molecular detection of human respiratory syncytial virus (RSV) are necessary to ensure the standardisation of reliable results. The Phase II, 2019–2020 World Health Organization (WHO) RSV EQA included 28 laboratories in 26 countries. The EQA panel evaluated performance in the molecular detection and subtyping of RSV-A and RSV-B. This manuscript describes the preparation, distribution, and analysis of the 2019–2020 WHO RSV EQA. Methods: Panel isolates underwent whole genome sequencing and in silico primer matching. The final panel included nine contemporary, one historical virus and two negative controls. The EQA panel was manufactured and distributed by the UK National External Quality Assessment Service (UK NEQAS). National laboratories used WHO reference assays developed by the United States Centers for Disease Control and Prevention, an RSV subtyping assay developed by the Victorian Infectious Diseases Reference Laboratory (Australia), or other in-house or commercial assays already in use at their laboratories. Results: An in silico analysis of isolates showed a good match to assay primer/probes. The panel was distributed to 28 laboratories. Isolates were correctly identified in 98% of samples for detection and 99.6% for subtyping. Conclusions: The WHO RSV EQA 2019–2020 showed that laboratories performed at high standards. Updating the composition of RSV molecular EQAs with contemporary strains to ensure representation of circulating strains, and ensuring primer matching with EQA panel viruses, is advantageous in assessing diagnostic competencies of laboratories. Ongoing EQAs are recommended because of continued evolution of mismatches between current circulating strains and existing primer sets. © 2023 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.

A group convened and led by the Virus Evolution Working Group of the World Health Organization reports on its deliberations and announces a naming scheme that will enable clear communication about SARS-CoV-2 variants of interest and concern. | | Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has a linear, unsegmented, positive-sense RNA genome. As with all viruses, SARS-CoV-2 continuously adapts to changing environments in real time via random genome mutations that are subject to natural selection. Most mutations are neutral or detrimental to the virus; however, a small number of mutations may provide a selective advantage, such as escape from the host immune system or resistance to antiviral drugs. Such mutations may also lead to increased fitness for transmissibility. As mutated forms of viruses or variants spread from person to person, they will eventually be detected at the population level.

Clostridioides difficile BI/NAP1/ribotype 027 is an epidemic hypervirulent strain found worldwide, including in Latin America. We examined the genomes and exoproteomes of two multilocus sequence type (MLST) clade 2 C. difficile strains considered hypervirulent: ICC-45 (ribotype SLO231/UK[CE]821), isolated in Brazil, and NAP1/027/ST01 (LIBA5756), isolated during a 2010 outbreak in Costa Rica. C. difficile isolates were cultured and extracellular proteins were analyzed using high-performance liquid chromatography-tandem mass spectrometry. Genomic analysis revealed that these isolates shared most of the gene composition. Only 83 and 290 NAP1/027 genes were considered singletons in ICC-45 and NAP1/027, respectively. Exoproteome analysis revealed 197 proteins, of which 192 were similar in both strains. Only five proteins were exclusive to the ICC-45 strain. These proteins were involved with catalytic and binding functions and indirectly interacted with proteins related to pathogenicity. Most proteins, including TcdA, TcdB, flagellin subunit, and cell surface protein, were overrepresented in the ICC-45 strain; 14 proteins, including mature S-layer protein, were present in higher proportions in LIBA5756. Data are available via ProteomeXchange with identifier PXD026218. These data show close similarity between the genome and proteins in the supernatant of two strains with hypervirulent features isolated in Latin America and underscore the importance of epidemiological surveillance of the transmission and emergence of new strains.

Many countries have reported antigenic divergence among circulating Bordetella pertussis strains, mainly in those countries which introduced the acellular pertussis (aP) vaccine. This phenomenon can be seen, for example, with the recent rise of pertactin (Prn)-deficient B. pertussis strains, one of the antigens included in aP vaccine formulas. The whole cell pertussis (wP) vaccine has been used in Brazil since 1977 for the primary pertussis, diphtheria and tetanus immunization series. In 2014, the aP vaccine was recommended for women during pregnancy to protect infants in the first months of life. Our objective was to determine the prevalence of Prn-deficiency in 511 isolates of B. pertussis collected in Brazil during 2010–2016. All isolates were characterized, through PFGE and serotyping, and screened for the loss of Prn by ELISA. Prn-deficiency was confirmed by immunoblotting, and identification of the possible genetic markers was performed with PCR and Sanger sequencing. Results indicate that 110 PFGE profiles are currently circulating, with five profiles representing the majority, and the predominant serotype 3, has been gradually replaced by serotype 2 and serotype 2,3. ELISA screening and immunoblotting identified three Prn-deficient isolates. Genotypic characterization by PCR and sequencing indicated that one isolate had a promoter mutation in prn, while the other two did not have an obvious genetic explanation for their deficiency. While the lack of Prn was identified in a few isolates, this study did not detect a relevant occurrence of Prn-deficiency, until 2016, confirming previous observations that Prn-deficiency is likely aP vaccine-driven. © 2021

BACKGROUND: Despite the well-known role of parents as caregivers, few studies have addressed their health outcomes related to the Zika virus epidemic. METHODS: A cross-sectional study was carried out with 146 primary caregivers of children 15-26 months of age, with laboratory and/or clinical evidence of Zika infection between August and October 2017 in three Brazilian municipalities: João Pessoa and Campina Grande in the state of Paraíba and Fortaleza in the state of Ceará. Caregivers reported on their child's life and health, family circumstances and underwent screening for stress using the Parenting Stress Index-Short Form. Children were evaluated for developmental delays and clinical outcomes. Differences in the prevalence of risk factors between caregivers with high or clinically relevant stress and those with normal stress were evaluated. RESULTS: Of the 146 participants, 13% (n = 19) were classified as having high or clinically relevant stress, all of them mothers. The two risk factors significantly and independently associated with high levels of stress, compared with individuals with normal stress levels, were "reporting difficulty in covering basic expenses" (adjusted OR 3.6 (95% CI 1.1-11.8; p = 0.034)) and "having a child with sleep problems" (adjusted OR 10.4 (95% CI 1.3-81.7; p = 0.026)). CONCLUSIONS: Some factors seem to contribute significantly more than others to the level of stress experienced by caregivers of children with evidence of Zika virus congenital infection. Interventions and preventive strategies should also target caregivers, who in turn will be able to respond to the unique characteristics of their child.

Background: Cataracts are a major cause of visual impairment and blindness in the United States and worldwide. Introduction: Risk factors for cataracts include age over 40 years, smoking, diabetes, low socioeconomic status, female sex, steroid use, ocular trauma, genetic factors, and exposure to ultraviolet-B light. Community-based telemedicine vision screenings can be an efficient method for detecting cataracts in underserved populations. The Philadelphia Telemedicine Glaucoma Detection and Follow-Up Study reports the prevalence and risk factors for cataracts in individuals screened and examined for glaucoma and other eye diseases. Materials and Methods: A total of 906 high-risk individuals were screened for glaucoma using telemedicine in seven primary care practices and four Federally Qualified Health Centers in Philadelphia. Participants with suspicious nerves or other abnormalities on fundus photographs, unreadable images, and ocular hypertension returned for an eye examination with an ophthalmologist at the same community location. Results: Of the participants screened through telemedicine, 347 (38.3%) completed a follow-up eye examination by an ophthalmologist. Of these, 267 (76.9%) were diagnosed with cataracts, of which 38 (14.2%) had visually significant cataracts. Participants who were diagnosed with visually significant cataract were more likely to be older (p < 0.001), have diabetes (p = 0.003), and worse visual acuity (p < 0.001). Discussion: Our study successfully detected and confirmed cataracts in a targeted, underserved urban population at high risk for eye disease. Conclusions: Telemedicine programs offer an opportunity to identify and refer individuals who would benefit from continuous follow-up eye care and treatment to improve visual function and quality of life.

Background: In 2015, the number of infants born with microcephaly increased in Paraiba, Brazil, after a suspected Zika virus outbreak. We did a retrospective case-control investigation to assess the association of microcephaly and Zika virus. Methods: We enrolled cases reported to the national database for microcephaly and born between Aug 1, 2015, and Feb 1, 2016, on the basis of their birth head circumference and total body length. We identified controls from the national birth registry and matched them to cases by location, aiming to enrol a minimum of two controls per case. Mothers of both cases and controls were asked about demographics, exposures, and illnesses and infants were measured at a follow-up visit 1-7 months after birth. We took blood samples from mothers and infants and classified those containing Zika virus IgM and neutralising antibodies as evidence of recent infection. We calculated prevalence of microcephaly and odds ratios (ORs) using a conditional logistic regression model with maximum penalised conditional likelihood, and combined these ORs with exposure probability estimates to determine the attributable risk. Findings: We enrolled 164 of 706 infants with complete information reported with microcephaly at birth, of whom we classified 91 (55%) as having microcephaly on the basis of their birth measurements, 36 (22%) as small, 21 (13%) as disproportionate, and 16 (10%) as not having microcephaly. 43 (26%) of the 164 infants had microcephaly at follow-up for an estimated prevalence of 5.9 per 1000 livebirths. We enrolled 114 control infants matched to the 43 infants classified as having microcephaly at follow-up. Infants with microcephaly at follow-up were more likely than control infants to be younger (OR 0.5, 95% CI 0.4-0.7), have recent Zika virus infection (21.9, 7.0-109.3), or a mother with Zika-like symptoms in the first trimester (6.2, 2.8-15.4). Once Zika virus infection and infant age were controlled for, we found no significant association between microcephaly and maternal demographics, medications, toxins, or other infections. Based on the presence of Zika virus antibodies in infants, we concluded that 35-87% of microcephaly occurring during the time of our investigation in northeast Brazil was attributable to Zika virus. We estimate 2-5 infants per 1000 livebirths in Paraiba had microcephaly attributable to Zika virus. Interpretation: Time of exposure to Zika virus and evidence of infection in the infants were the only risk factors associated with microcephaly. This investigation has improved understanding of the outbreak of microcephaly in northeast Brazil and highlights the need to obtain multiple measurements after birth to establish if an infant has microcephaly and the need for further research to optimise testing criteria for congenital Zika virus infection. Funding: Centers for Disease Control and Prevention.

Background: The etiology of acute watery diarrhea remains poorly characterized, particularly after rotavirus vaccine introduction. Methods: We performed quantitative polymerase chain reaction for multiple enteropathogens on 878 acute watery diarrheal stools sampled from 14643 episodes captured by surveillance of children <5 years of age during 2013-2014 from 16 countries. We used previously developed models of the association between pathogen quantity and diarrhea to calculate pathogen-specific weighted attributable fractions (AFs). Results: Rotavirus remained the leading etiology (overall weighted AF, 40.3% [95% confidence interval {CI}, 37.6%-44.3%]), though the AF was substantially lower in the Americas (AF, 12.2 [95% CI, 8.9-15.6]), based on samples from a country with universal rotavirus vaccination. Norovirus GII (AF, 6.2 [95% CI, 2.8-9.2]), Cryptosporidium (AF, 5.8 [95% CI, 4.0-7.6]), Shigella (AF, 4.7 [95% CI, 2.8-6.9]), heat-stable enterotoxin-producing Escherichia coli (ST-ETEC) (AF, 4.2 [95% CI, 2.0-6.1]), and adenovirus 40/41 (AF, 4.2 [95% CI, 2.9-5.5]) were also important. In the Africa Region, the rotavirus AF declined from 54.8% (95% CI, 48.3%-61.5%) in rotavirus vaccine age-ineligible children to 20.0% (95% CI, 12.4%-30.4%) in age-eligible children. Conclusions: Rotavirus remained the leading etiology of acute watery diarrhea despite a clear impact of rotavirus vaccine introduction. Norovirus GII, Cryptosporidium, Shigella, ST-ETEC, and adenovirus 40/41 were also important. Prospective surveillance can help identify priorities for further reducing the burden of diarrhea.

In mid-2015, Salvador, Brazil, reported an outbreak of Guillain-Barre syndrome (GBS), coinciding with the introduction and spread of Zika virus (ZIKV). We found that GBS incidence during April-July 2015 among those ≥12 years of age was 5.6 cases/100,000 population/year and increased markedly with increasing age to 14.7 among those ≥60 years of age. We conducted interviews with 41 case-patients and 85 neighborhood controls and found no differences in demographics or exposures prior to GBS-symptom onset. A higher proportion of case-patients (83%) compared to controls (21%) reported an antecedent illness (OR 18.1, CI 6.9-47.5), most commonly characterized by rash, headache, fever, and myalgias, within a median of 8 days prior to GBS onset. Our investigation confirmed an outbreak of GBS, particularly in older adults, that was strongly associated with Zika-like illness and geo-temporally associated with ZIKV transmission, suggesting that ZIKV may result in severe neurologic complications.

BACKGROUND: Utstein-style guidelines use an established consensus process, endorsed by the international resuscitation community, to facilitate and structure resuscitation research and publication. The first "Guidelines for Uniform Reporting of Data From Drowning" were published over a decade ago. During the intervening years, resuscitation science has advanced considerably, thus making revision of the guidelines timely. In particular, measurement of cardiopulmonary resuscitation elements and neurological outcomes reporting have advanced substantially. The purpose of this report is to provide updated guidelines for reporting data from studies of resuscitation from drowning. METHODS: An international group with scientific expertise in the fields of drowning research, resuscitation research, emergency medical services, public health, and development of guidelines met in Potsdam, Germany, to determine the data that should be reported in scientific articles on the subject of resuscitation from drowning. At the Utstein-style meeting, participants discussed data elements in detail, defined the data, determined data priority, and decided how data should be reported, including scoring methods and category details. RESULTS: The template for reporting data from drowning research was revised extensively, with new emphasis on measurement of quality of resuscitation, neurological outcomes, and deletion of data that have proved to be less relevant or difficult to capture. CONCLUSIONS: The report describes the consensus process, rationale for selecting data elements to be reported, definitions and priority of data, and scoring methods. These guidelines are intended to improve the clarity of scientific communication and the comparability of scientific investigations.

Insecticide resistance is one of the primary threats to the recent gains in malaria control. This is especially true in Guinea, where long-lasting insecticidal nets are currently the primary vector control intervention. To better inform the national malaria control program on the current status of insecticide resistance in Guinea, resistance bioassays were conducted, using Anopheles gambiae s.l. Giles, in three sites. Molecular analyses were also done on An. gambiae s.l. to determine the species and find whether the target-site mutations kdr and Ace1R were present. Susceptibility tests revealed resistance to DDT and pyrethroids, although mosquitoes were susceptible to deltamethrin in two of the three sites tested. Mosquitoes were susceptible to bendiocarb, except in Kissidougou, Guinea. The kdr-west mutation was widespread and the frequency was 60% or more in all sites. However, the Ace1R mutation was present in low levels. Insecticide susceptibility should continue to be monitored in Guinea to ensure insecticide-based vector control methods remain effective.

OBJECTIVE: To investigate the association between neighbourhood food availability and the consumption of ready-to-consume products (RCP), either processed or ultra-processed, and unprocessed/minimally processed foods (UF-MPF) by children. DESIGN: Cross-sectional. 24 h Dietary recalls were collected from children from January 2010 to June 2011. Neighbourhood food availability data were collected from 672 food stores located within 500 m of participants' homes, using an adapted and validated instrument. Neighbourhood-level socio-economic status (SES) was obtained by calculating the mean years of household head's education level in each census tract covered by 500 m buffers. Foods that were consumed by children and/or available in the food stores were classified based on their degree of industrial processing. Multilevel random-effect models examined the association between neighbourhood food availability and children's diets. SETTING: Santos, Brazil. SUBJECTS: Children (n 513) under 10 years old (292 aged <6 years, 221 aged ≥6 years). RESULTS: The availability of RCP in food stores was associated with increased RCP consumption (P<0.001) and decreased UF-MPF consumption (P<0.001). The consumption of UF-MPF was positively associated with neighbourhood-level SES (P<0.01), but not with the availability of UF-MPF in the neighbourhood. CONCLUSIONS: Results suggest that food policies and interventions that aim to reduce RCP consumption in Santos and similar settings should focus on reducing the availability in food stores. The results also suggest that interventions should not only increase the availability of UF-MPF in lower-SES neighbourhoods, but should strive to make UF-MPF accessible within these environments.

Information on pneumococcal carriage in the pre-vaccine period is essential to predict and assess the impact of PCV in settings where disease surveillance is particularly difficult. Therefore, we present data on pneumococcal carriage before the introduction of the 10-valent-pneumococcal conjugate vaccine (PCV10) in Brazil. We conducted a prospective study on a cohort of 203 children aged <5 years old, randomly selected in an urban community located in the periphery of the city of Salvador, Brazil and followed them from January/2008 to January/2009. Nasopharyngeal swabs were collected from each child at four times. In total, 721 swabs were collected, yielding a pneumococcal carriage prevalence of 55% (n=398). In multivariate analyses, the variables associated with carriage were having contact with three or more children <2 years old (OR, 2.00; 95% CI 1.33-2.89) and living in a house with an average of 3 residents per room (OR, 1.77; 95% CI 1.05-3.10). Also, white participants were more likely to be protected from colonization (OR, 0.52; 95% CI 0.29-0.93), and prevalence of carriage varied over time, with lower prevalence occurring from February to June (OR, 0.53; 95% CI 0.37-0.78) compared to July to January. Contact with children under 2 years of age and living in crowded housing also were associated with colonization by highly invasive serotypes, although this relationship was not significant. The most prevalent vaccine serotypes were 6A/B (25.4%), 19F (10.1%) and 14 (9.0%), while the most prevalent non-vaccine serotypes were 16F (4.8%), 15B/C (4.5%) and 6C/D (3.5%). Overall, 38.4% (153/398) of the isolates were non-susceptible to penicillin, and of those, 73.8% (113/153) were non-susceptible to trimethoprim/sulfamethoxazole. Colonization rate by PCV10 serotypes was 52.2%. Routine PCV10 vaccination can lead to significant changes in pneumococcal serotypes found in NP colonization, indicating a need for continued monitoring, especially in crowded settings, as occurs in Brazil's slums.

Emerging and re-emerging vector-borne diseases such as chikungunya and dengue and associated Aedes vectors are expanding their historical ranges; thus, there is a need for the development of novel insecticides for use in vector control programs. The mosquito toxicity of a novel insecticide and repellent consisting of medium-chain carbon fatty acids (C8910) was examined. Determination of LC50 and LC90 was made against colony-reared Aedes aegypti (L.) and Aedes albopictus (Skuse) using probit analysis on mortality data generated by Centers for Disease Control and Prevention bottle bioassays. Six different concentrations of C8910 + silicone oil yielded an LC50 of 160.3 microg a.i/bottle (147.6-182.7) and LC90 of 282.8 (233.2-394.2) in Ae. aegypti; five concentrations yielded an LC50 of 125.4 (116.1-137.6) and LC90 of 192.5 (165.0-278.9) in Ae. albopictus. Further development of C8910 and similar compounds could provide vector control specialists novel insecticides for controlling insect disease vectors.

Pertussis remains an important public health problem in many countries despite extensive immunization. Cultures and real-time PCR (RT-PCR) assays are the recommended pertussis diagnostic tests, but they lack sensitivity at the later stage of the disease. This study introduces the IgG anti-pertussis toxin enzyme-linked immunosorbent assay (PT ELISA) in our routine diagnosis to improve disease burden estimation. Serum samples and nasopharyngeal swabs (n = 503) were collected at the same time from patients presenting with cough illness suspected of being pertussis and tested by the PT ELISA and culture and/or RT-PCR, respectively. Patients were separated into three age groups: group 1, <1 year (n = 260; mean age, 3 months), group 2, 1 to 6 years (n = 81; mean age, 3 years), and group 3, ≥7 years (n = 162; mean age, 26 years). The times (means) from cough onset to specimen collection were 16, 24, and 26 days, respectively. In group 1, 83 (82.2%) of 101 positive cases were positive for pertussis by culture/RT-PCR, while 40 (39.6%) tested positive by PT ELISA. In group 2, 6 (19.4%) of 31 positive cases were culture/RT-PCR positive, and 29 (93.6%) were seropositive. In group 3, 13 (13.8%) of 94 positive cases were positive by culture/RT-PCR and 91 (96.8%) were positive by serology. Culture/RT-PCR detected more cases of pertussis in infants (P < 0.0001), whereas the PT ELISA detected more cases in adolescents and adults (P < 0.0001). The timing between cough onset and specimen collection or recent vaccination may have partially affected our results. Serology is a suitable, cost-effective, and complementary pertussis diagnostic tool, especially among older children, adolescents, and adults during the later disease phase.

A recent clinical trial in African children demonstrated the potential utility of merozoite surface protein (MSP)-3 as a vaccine against Plasmodium falciparum malaria. The present study evaluated the use of Plasmodium vivax MSP-3 (PvMSP-3) as a target antigen in vaccine formulations against malaria caused by P. vivax . Recombinant proteins representing MSP-3alpha (PvMSP-3) and MSP-3beta of P. vivax were expressed as soluble histidine-tagged bacterial fusions. Antigenicity during natural infection was evaluated by detecting specific antibodies using sera from individuals living in endemic areas of Brazil. A large proportion of infected individuals presented IgG antibodies to PvMSP-3alpha (68.2%) and at least 1 recombinant protein representing PvMSP-3beta (79.1%). In spite of the large responder frequency, reactivity to both antigens was significantly lower than was observed for the immunodominant epitope present on the 19-kDa C-terminal region of PvMSP-1. Immunogenicity of the recombinant proteins was studied in mice in the absence or presence of different adjuvant formulations. PvMSP-3beta, but not PvMSP-3alpha, induced a TLR4-independent humoral immune response in the absence of any adjuvant formulation. The immunogenicity of the recombinant antigens were also tested in formulations containing different adjuvants (Alum, flagellin, CpG, Quil A,TiterMax(R) and incomplete Freunds adjuvant) and combinations of two adjuvants (Alum plus flagellin, and CpG plus flagellin). Recombinant PvMSP-3alpha and PvMSP-3beta elicited higher antibody titers capable of recognizing infected erythrocytes harvested from malaria patients. Our results confirm that P. vivax MSP-3 antigens are immunogenic during natural infection, and the corresponding recombinant proteins may be useful in elucidating their vaccine potential.

BACKGROUND: Although cerebrospinal fluid (CSF) culture is the diagnostic reference standard for bacterial meningitis, its sensitivity is limited, particularly when antibiotics were previously administered. CSF Gram staining and real-time PCR are theoretically less affected by antibiotics; however, it is difficult to evaluate these tests with an imperfect reference standard. METHODS AND FINDINGS: CSF from patients with suspected meningitis from Salvador, Brazil were tested with culture, Gram stain, and real-time PCR using S. pneumoniae, N. meningitidis, and H. influenzae specific primers and probes. An antibiotic detection disk bioassay was used to test for the presence of antibiotic activity in CSF. The diagnostic accuracy of tests were evaluated using multiple methods, including direct evaluation of Gram stain and real-time PCR against CSF culture, evaluation of real-time PCR against a composite reference standard, and latent class analysis modeling to evaluate all three tests simultaneously. RESULTS: Among 451 CSF specimens, 80 (17.7%) had culture isolation of one of the three pathogens (40 S. pneumoniae, 36 N. meningitidis, and 4 H. influenzae), and 113 (25.1%) were real-time PCR positive (51 S. pneumoniae, 57 N. meningitidis, and 5 H. influenzae). Compared to culture, real-time PCR sensitivity and specificity were 95.0% and 90.0%, respectively. In a latent class analysis model, the sensitivity and specificity estimates were: culture, 81.3% and 99.7%; Gram stain, 98.2% and 98.7%; and real-time PCR, 95.7% and 94.3%, respectively. Gram stain and real-time PCR sensitivity did not change significantly when there was antibiotic activity in the CSF. CONCLUSION: Real-time PCR and Gram stain were highly accurate in diagnosing meningitis caused by S. pneumoniae, N. meningitidis, and H. influenzae, though there were few cases of H. influenzae. Furthermore, real-time PCR and Gram staining were less affected by antibiotic presence and might be useful when antibiotics were previously administered. Gram staining, which is inexpensive and commonly available, should be encouraged in all clinical settings.

OBJECTIVE: Knowledge of Bordetella pertussis circulating in Latin America is limited. Therefore, the goal of this study was to use pulsed-field gel electrophoresis and serotyping to characterize B. pertussis strains isolated in the city of Sao Paulo, Brazil. METHODS: This study, conducted between 2006 and 2008, analyzed 652 nasopharyngeal swabs from suspected pertussis cases and contacts, collected from 37 sentinel hospitals in Sao Paulo. Randomized samples of 91 (70%) strains of B. pertussis were subtyped by pulsed-field gel electrophoresis and serotyping. RESULTS: Ninety-seven percent of strains from Sao Paulo were serotyped as Fim3. Fourteen pulsed-field gel electrophoresis profiles were identified; the most prevalent (57%) is also the most prevalent in the USA. CONCLUSIONS: These data, in conjunction with surveillance activities, may impact strategies regarding prevention and control of pertussis in the region, providing useful information for introduction of new vaccination strategies and reduction of risk of transmission to infants less than 6 months of age.

BACKGROUND: An epidemic of acute gastroenteritis occurred in Rio Branco City, Acre State, in Brazil's Amazon region in 2005. An investigation was conducted to confirm the etiology and identify possible risk factors for death. METHODS: Rio Branco municipality surveillance data for the period May to October 2005 were reviewed. In a case-control study, children who died following acute gastroenteritis were compared to age-matched controls with acute gastroenteritis who survived. Rotavirus A (RV-A) was investigated in 799 stool samples and genotyped by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The cumulative incidence of diarrhea in children aged <5 years was 21%. A fatal outcome was significantly associated with uncovered household water storage containers. RV-A was identified in 88% of samples and G9 was the prevalent genotype (71%). CONCLUSIONS: Oral rehydration solution and boiling or chlorinating drinking water likely limited mortality. This epidemic was caused by RV-A genotype G9. After the outbreak, a rotavirus vaccine was introduced into the official childhood immunization schedule in Brazil.