Understanding child disability: Factors associated with child disability at the Iganga-Mayuge Health and Demographic Surveillance Site in Uganda

Introduction

There is scarcity of data on children with disabilities living in low-and-middle-income countries, including Uganda. This study describes disability prevalence and explores factors associated with different disability categories. It highlights the value of using a standardized, easy-to-use tool to determine disability in children and contextualizing disability in children in light of their developmental needs.

Methods

A cross-sectional study was conducted between September 2018–January 2019 at the Iganga-Mayuge Health and Demographic Surveillance Site in Uganda. Respondents were caregivers of children between 5–17 years and were administered an in-depth Child Functioning Module (CFM). The outcome variable, disability, was defined as an ordered categorical variable with three categories–mild, moderate, and severe. Generalized ordered logit model was applied to explore factors associated with disability categories.

Results

Out of 1,842 caregivers approached for the study, 1,439 (response: 78.1%) agreed to participate in the study. Out of these 1,439, some level of disability was reported by 67.89% (n = 977) of caregivers. Of these 977 children with disability, 48.01% (n = 692) had mild disability and 15.84% (n = 228) had moderate disability, while 3.96% (n = 57) had severe disability. The mean (SD) score for mild disability was 2.22±1.17, with a median of 2. The mean and median for moderate disability was 5.26±3.28 and 4 (IQR:3–6), and for severe disability was 14.23±9.51 and 12 (IQR:6–22). The most common disabilities reported were depression (54.83%) and anxiety (50.87%). Statistically significant association was found for completion of immunization status and school enrollment when controlled for a child’s age, sex, having a primary caregiver, age of mother at child’s birth, family system, family size and household wealth quintile.

Conclusion

This study suggests association between incomplete immunization status and school enrollment for children with disability. These are areas for further exploration to ensure inclusive health and inclusive education of children with disabilities in Uganda.

Community-Acquired Pneumonia in Canada During COVID-19

Dealing with coronavirus disease 2019 (COVID-19) has been a monumental test of medical skills and resources worldwide. The management of community-acquired pneumonia (CAP) can at times be difficult, but treating CAP in the setting of COVID-19 can be particularly trying and confusing and raises a number of challenging questions relating to etiology, diagnosis, and treatment. This article is based on the authors’ experiences and presents an overview of how CAP during COVID-19 is handled in Canada. We touch on the issues of microbial etiology in patients with CAP in the setting of COVID-19 as well as diagnostic, site of care, and treatment approaches. Published guidelines are the basis of management of CAP and are discussed in the context of Canadian data. We also outline the usual treatment approaches to COVID-19, particularly in patients who have been hospitalized.

The frequency of interleukin-1β-producing monocytes is significantly associated with varicella-zoster responses of nursing home residents

Previous studies have demonstrated that the status of the T cell compartment and inflammation-related factors are associated with the immunogenicity of the varicella-zoster virus (VZV) vaccine in older adults; however, little is known about the roles of other immune cell subsets known to influence the generation and maintenance of immunological memory. Responses to a live-attenuated VZV vaccine were studied in relation to peripheral blood mononuclear cell (PBMC) composition and function in a sample of 30 nursing home residents (aged 80-99 years). Interferon-gamma enzyme-linked immunospot (ELISPOT) was used to measure VZV responses at baseline and 6 weeks following vaccination, and associations were sought with the frequencies of monocytes and T, B and natural killer (NK) cells and the production and secretion of cytokines following their ex-vivo stimulation with different agents. While only the frequency of interleukin (IL)-6⁺ CD14⁺ monocytes was inversely associated with post-vaccination VZV response, amounts of IL-1β, IL-10, IL-17A and tumour necrosis factor (TNF) secreted by PBMCs and the frequency of IL-1β⁺ CD14⁺ monocytes was positively correlated with pre-vaccination VZV response. Furthermore, both bivariate correlation and causal mediation analyses supported the notion that IL-1β⁺ CD14⁺ monocytes were significant mediators of the associations between IL-1β and TNF secretion by PBMCs and pre-vaccination VZV responses. Our findings implicate a strong cytokine response mediated by inflammatory IL-1β⁺ monocytes in coordinating responses of long-lived VZV-reactive memory T cells, but with an opposing effect of IL-6⁺ CD14⁺ monocytes. Whether monocyte status promotes or inhibits the induction and/or maintenance of these memory T cells later in life has yet to be determined.

Measuring child functioning: Assessing correlation and agreement between caregiver and child responses at the Iganga-Mayuge health and demographic surveillance site in Uganda

INTRODUCTION

Empirical data is scare on assessment of concordance between caregiver-child responses on child functioning.

OBJECTIVE

To assess correlation and agreement between children (11-17 years old) and their caregivers' responses to the UNICEF/Washington Group Child Functioning Module (CFM) at the Iganga-Mayuge Health and Demographic Surveillance Site (IM-HDSS) in Uganda.

METHODS

CFM with 24-questions corresponding to 13 domains of functioning was administered to children between 11 and 17 years of age and their caregivers. Descriptive analyses of the child/caregiver responses were conducted. Correlation and agreement between caregiver and child responses were assessed.

RESULTS

Of the 217 caregiver/child pairs eligible for this study, 181 pairs agreed to participate (83.4%). The mean age of children was 13.9 ± 1.9 years, and 56.4% were males. Cronbach's alpha was 0.892 and 0.886 for the caregiver and child versions of CFM respectively, showing good internal consistency in both. There was a significant overall agreement between mean score of caregiver (5.36 ± 5.63 out of 39) and child (5.45 ± 5.34) pairs. Spearman's rank correlation between the pairs was 0.806 (strong positive correlation). Bland-Altman plots for CFM scores showed greater agreement between caregiver and child at lower scores. Percentage agreement between the pairs for overall disability was greater for mild (83.53%) and moderate (79.37%) categories as compared to the severe (66.67%) category. There was substantial agreement (kappa 0.623) for overall disability between the pairs.

CONCLUSION

This study indicates that there is significant correlation and agreement between self-reported caregiver-child pair responses, opening the way for considering children as CFM respondents, when possible.

The Impact of Prior Season Vaccination on Subsequent Influenza Vaccine Effectiveness to Prevent Influenza-related Hospitalizations Over 4 Influenza Seasons in Canada

BACKGROUND

Recent studies have demonstrated the possibility of negative associations between prior influenza vaccines and subsequent influenza vaccine effectiveness (VE), depending on season and strain. We investigated this association over 4 consecutive influenza seasons (2011-2012 through 2014-2015) in Canada.

METHODS

Using a matched test-negative design, laboratory-confirmed influenza cases and matched test-negative controls admitted to hospitals were enrolled. Patients were stratified into 4 groups according to influenza vaccine history (not vaccinated current and prior season [referent], vaccinated prior season only, vaccinated current season only, and vaccinated both current and prior season). Conditional logistic regression was used to estimate VE; prior vaccine impact was assessed each season for overall effect and effect stratified by age (<65 years, ≥65 years) and type/subtype (A/H1N1, A/H3N2, influenza B).

RESULTS

Overall, mainly nonsignificant associations were observed. Trends of nonsignificant decreased VE among patients repeatedly vaccinated in both prior and current season relative to the current season only were observed in the A/H3N2-dominant seasons of 2012-2013 and 2014-2015. Conversely, in 2011-2012, during which B viruses circulated, and in 2013-2014, when A/H1N1 circulated, being vaccinated in both seasons tended to result in a high VE in the current season against the dominant circulating subtype.

CONCLUSIONS

Prior vaccine impact on subsequent VE among Canadian inpatients was mainly nonsignificant. Even in circumstances where we observed a trend of negative impact, being repeatedly vaccinated was still more effective than not receiving the current season's vaccine. These findings favor continuation of annual influenza vaccination recommendations, particularly in older adults.

CLINICAL TRIALS REGISTRATION

NCT01517191.

Adaptation and validation of UNICEF/Washington group child functioning module at the Iganga-Mayuge health and demographic surveillance site in Uganda

BACKGROUND

The UNICEF/Washington Group Child Functioning Module (CFM) assesses child functioning among children between 5 and 17 years of age. This study adapted and validated the CFM at the Iganga-Mayuge Health and Demographic Surveillance Site (IM-HDSS) in Uganda.

METHODS

This cross-sectional study was conducted between September 2018-January 2019 at the IM-HDSS. Respondents were caregivers of children between 5 and 17 years of age who were administered modified Washington Group short set (mWG-SS) and CFM. The responses were recorded on a 4-point Likert scale. Descriptive analysis was conducted on child and caregiver demographic characteristics. Exploratory factor analysis (EFA) assessed underlying factor structure, dimensionality and factor loadings. Cronbach's alpha was reported as an assessment of internal consistency. Face validity was assessed during the translation process, and concurrent validity of CFM was assessed through comparison with disability short form.

RESULTS

Out of 1842 caregivers approached, 1439 (78.1%) participated in the study. Mean age of children was 11.06 ± 3.59 years, 51.4% were males, and 86.1% had a primary caregiver. Based on EFA, vision, hearing, walking, self-care, communication, learning, remembering, concentrating, accepting change, behavior control, and making friends loaded on factor 1 - "Motor and Cognition," while anxiety and depression loaded on factor 2 - "Mood". Cronbach's alpha for the overall CFM was 0.899 (good internal consistency). Cronbach's alpha for each extracted factor was excellent, motor and cognition (0.904), and mood (0.902). CFM had acceptable face validity. Spearman's rank correlation between scores of CFM and modified WG short set was 0.51 (p-value < 0.001). The overall mean CFM score was 2.47 ± 3.82 out of 39. The mean score for Mood (1.35 ± 1.42 out of 6) was higher compared to Motor and Cognition (1.12 ± 3.06 out of 33). Comparing modified WG short set and CFM Likert responses, the percent agreement was greatest for "cannot do at all."

CONCLUSION

CFM is a two-factor, valid and reliable scale for assessing disability in Uganda and can be applied to other similar settings to contribute towards disability data from the region. It is an easy-to-administer tool that can help in deeper understanding of context-specific burden and extent of disability in children between 5 and 17 years of age.

Sources of viral respiratory infections in Canadian acute care hospital healthcare personnel

BACKGROUND

Viral respiratory illnesses are common causes of outbreaks and can be fatal to some patients.

AIM

To investigate the association between laboratory-confirmed viral respiratory infections and potential sources of exposure during the previous 7 days.

METHODS

In this nested case-control analysis, healthcare personnel from nine Canadian hospitals who developed acute respiratory illnesses during the winters of 2010/11-2013/14 submitted swabs that were tested for viral pathogens. Associated illness diaries and the weekly diaries of non-ill participants provided information on contact with people displaying symptoms of acute respiratory illness in the previous week. Conditional logistic regression assessed the association between cases, who were matched by study week and site with controls with no respiratory symptoms.

FINDINGS

There were 814 laboratory-confirmed viral respiratory illnesses. The adjusted odds ratio (aOR) of a viral illness was higher for healthcare personnel reporting exposures to ill household members [7.0, 95% confidence interval (CI) 5.4-9.1], co-workers (3.4, 95% CI 2.4-4.7) or other social contacts (5.1, 95% CI 3.6-7.1). Exposures to patients with respiratory illness were not associated with infection (aOR 0.9, 95% CI 0.7-1.2); however, healthcare personnel with direct patient contact did have higher odds (aOR 1.3, 95% CI 1.1-1.6). The aORs for exposure and for direct patient contact were similar for illnesses caused by influenza.

CONCLUSION

Community and co-worker contacts are important sources of viral respiratory illness in healthcare personnel, while exposure to patients with recognized respiratory infections is not associated. The comparatively low risk associated with direct patient contact may reflect transmission related to asymptomatic patients or unrecognized infections.

Validation of the Seegene RV15 multiplex PCR for the detection of influenza A subtypes and influenza B lineages during national influenza surveillance in hospitalized adults

Background. The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network (CIRN SOS) has been performing active influenza surveillance since 2009 (ClinicalTrials.gov identifier: NCT01517191). Influenza A and B viruses are identified and characterized using real-time reverse-transcriptase polymerase chain reaction (RT-PCR), and multiplex testing has been performed on a subset of patients to identify other respiratory virus aetiologies. Since both methods can identify influenza A and B, a direct comparison was performed.Methods. Validated real-time RT-PCRs from the World Health Organization (WHO) to identify influenza A and B viruses, characterize influenza A viruses into the H1N1 or H3N2 subtypes and describe influenza B viruses belonging to the Yamagata or Victoria lineages. In a subset of patients, the Seeplex RV15 One-Step ACE Detection assay (RV15) kit was also used for the detection of other respiratory viruses.Results. In total, 1111 nasopharyngeal swabs were tested by RV15 and real-time RT-PCRs for influenza A and B identification and characterization. For influenza A, RV15 showed 98.0 % sensitivity, 100 % specificity and 99.7 % accuracy. The performance characteristics of RV15 were similar for influenza A subtypes H1N1 and H3N2. For influenza B, RV15 had 99.2 % sensitivity, 100 % specificity and 99.8 % accuracy, with similar assay performance being shown for both the Yamagata and Victoria lineages.Conclusions. Overall, the detection of circulating subtypes of influenza A and lineages of influenza B by RV15 was similar to detection by real-time RT-PCR. Multiplex testing with RV15 allows for a more comprehensive respiratory virus surveillance in hospitalized adults, without significantly compromising the reliability of influenza A or B virus detection.

Measuring child functioning: the Unicef/ Washington Group Module

The Convention on the Rights of the Child, adopted in 1989 included the first explicit provision relating to the rights of children with disabilities. It included a prohibition against discrimination on the grounds of disability (art. 2), and obligations to provide services for children with disabilities, in order to enable them to achieve the fullest possible social integration (art.23)… 

The development and testing of a module on child functioning for identifying children with disabilities on surveys. I: Background

This is the first of three papers that will document the development of a survey module on child functioning developed by UNICEF in collaboration with the Washington Group on Disability Statistics (WG), and demonstrate - both conceptually and through test results - the strengths of that module compared with alternative tools for identifying children with disabilities in household surveys. This first paper in the series sets the background and reviews the literature leading to the development of the UNICEF/WG Child Functioning Module (CFM) and presents the WG Short Set of questions (WG-SS) and the Ten Question Screening Instrument (TQSI) as precursors, outlining some of their shortcomings and how the UNICEF/WG CFM was designed to meet those challenges. Subsequent articles will summarize results from the cognitive and field testing of the CFM including comparisons with results derived from the TQSI and the WG-SS.

The development and testing of a module on child functioning for identifying children with disabilities on surveys. III: Field testing

BACKGROUND

A module on child functioning developed by UNICEF and the Washington Group on Disability Statistics (WG) for use in censuses and surveys reflects current thinking around disability measurement and is intended to produce internationally comparable data. The Child Functioning Module (CFM) was developed in response to limitations of the Ten Question Screening Instrument (TQSI) for use in surveys and builds on the WG Short Set (WG-SS) of questions that was designed to capture disability in censuses, particularly among the adult population.

OBJECTIVE

This paper documents the testing of the module and summarizes its results, including a description of prevalence levels across countries using different cut-offs, and comparisons with prevalence levels obtained using the TQSI and the WG-SS.

METHODS

Field tests were conducted in Samoa as part of the 2014 Demographic and Health Survey and in Mexico as part of the 2015 National Survey of Boys, Girls and Women. The module was also implemented in Serbia as part of a dedicated survey conducted in the province of Vojvodina, in February 2016.

RESULTS

Using the recommended cut-offcut-off, the percentage of children reported as having functional difficulty ranges from 1.1% in Serbia to 2% in Mexico among children aged 2-4 years, and from 3.2% in Samoa to 11.2% in Mexico among children aged 5-17 years. Across all three countries, the prevalence of functional difficulty was highest in the socio-emotional domains. A comparison of the prevalence levels obtained using the WG-SS and the CFM shows that, except for the question on cognition/learning, the WG-SS and the CFM are relatively close for children aged 5-17 years for the domains that are included in both question sets, but the WG-SS excludes many children identified by the CFM in other domains. The comparison between the TQSI and the CFM shows that, while the prevalence estimates are similar for seeing and hearing, significant differences affect other domains, particularly cognition/learning and communication.

CONCLUSIONS

The CFM addresses a full range of functional domains that are important for child development. The module represents an improvement on the TQSI in that it allows for scaled responses to determine the degree of difficulty, and so can separate out many potential false positives. The module is also preferred over the WG-SS for collecting data on children, first, because most of the questions in the WG-SS are not suitable for children under the age of 5 years, and second, because the WG-SS leaves out important functional domains for children aged 5-17 years, namely those related to developmental disabilities and behavioural issues.

Role of pharmaceutical care for self-administered pulmonary tuberculosis treatment in Thailand

WHAT IS KNOWN AND OBJECTIVE

With resource constraints in Thailand, directly observed therapy (DOT) for treating tuberculosis (TB) may not be feasible to implement. To improve patients' adherence, hospitals either modify DOT or adopt different approaches: pharmaceutical care or home visit. Our objective was to assess pulmonary TB treatment success rate of pharmaceutical care compared to home visit and modified DOT in Thailand.

METHODS

We conducted a retrospective cohort study using data collected in adult pulmonary TB patients starting treatment between October 2010 and September 2013 in three hospitals in Thailand. This study was approved by the Research Ethics Board at each of the participating hospitals. We built a propensity score matching to account for differences in patient baseline characteristics.

RESULTS

Analysis included 1398 patients. Before matching, the treatment success rate for patients receiving pharmaceutical care was 94.9%, home visit 93.6% and modified DOT 90.1%. The propensity score-matched cohorts indicated that differences in the treatment success rate were not statistically significant when comparing pharmaceutical care with either home visit (success rate: 92.76% vs 94.74%, risk difference: 1.97%, 95% CI -3.64 to 7.59) or modified DOT (success rate 93.37% for both, risk difference: 0%, 95% CI -5.30 to 5.30).

WHAT IS NEW AND CONCLUSION

Pharmaceutical care, home visit and modified DOT are all associated with high success rate for pulmonary TB treatment and exceeded the WHO target, in this retrospective analysis.

Field testing a draft version of the UNICEF/Washington Group Module on child functioning and disability. Background, methodology and preliminary findings from Cameroon and India

Background

Global child disability data are generally non-comparable, comprising different tools, methodologies and disability definitions. UNICEF and The Washington Group on Disability Statistics (WG) have developed a new tool on child functioning and disability to address this need.

Aims

The aim of this paper is to describe the development of the new module, and to present an independent field test of the draft module in two contrasting settings.

Methods

UNICEF and the WG developed a parent-reported survey module to identify children aged 2-17 years with functional difficulties in population-based surveys through: review of existing documentation, consultation with experts and cognitive testing. A field test of the draft module was undertaken in Cameroon and India within a population-based survey. Functional limitation in each of 14 domains was scored on a scale comprising "no difficulty", "some difficulty", "a lot of difficulty" and "cannot do".

Results

In all, 1713 children in Cameroon and 1101 children in India were assessed. Sixty-four percent of children in Cameroon and 35% of children in India were reported to have at least some difficulty in one or more domain. The proportion reported to have either "a lot of difficulty" or "cannot do" was 9% in Cameroon and 4% in India. There were no significant differences in reported functional difficulties by sex but children aged 2-4 were reported to have fewer functional difficulties of any kind compared with older children in both countries.

Conclusion

Comparable estimates were generated between the two countries, providing an initial overview of the tool's outputs. The continued development of this standardised questionnaire for the collection of robust and reliable data on child disability is essential.

Identification of genetic variants associated with susceptibility to West Nile virus neuroinvasive disease

West Nile virus (WNV) infection results in a diverse spectrum of outcomes, and host genetics are likely to influence susceptibility to neuroinvasive disease (West Nile neuroinvasive disease (WNND)). We performed whole-exome sequencing of 44 individuals with WNND and identified alleles associated with severe disease by variant filtration in cases, kernel association testing in cases and controls and single-nucleotide polymorphism (SNP) imputation into a larger cohort of WNND cases and seropositive controls followed by genome-wide association analysis. Variant filtration prioritized genes based on the enrichment of otherwise rare variants, but did not unambiguously implicate variants shared by a majority of cases. Kernel association demonstrated enrichment for risk and protective alleles in the human leukocyte antigen (HLA)-A and HLA-DQB1 loci that have well understood roles in antiviral immunity. Two loci, HERC5 and an intergenic region between CD83 and JARID2, were implicated by multiple imputed SNPs and exceeded genome-wide significance in a discovery cohort (n=862). SNPs at two additional loci, TFCP2L1 and CACNA1H, achieved genome-wide significance after association testing of directly genotyped and imputed SNPs in a discovery cohort (n=862) and a separate replication cohort (n=1387). The context of these loci suggests that immunoregulatory, ion channel and endothelial barrier functions may be important elements of the host response to WNV.

Interim estimates of 2014/15 influenza vaccine effectiveness in preventing laboratory-confirmed influenza-related hospitalisation from the Serious Outcomes Surveillance Network of the Canadian Immunization Research Network, January 2015

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Factors Associated With Critical-Care Healthcare Workers' Adherence to Recommended Barrier Precautions During the Toronto Severe Acute Respiratory Syndrome Outbreak

Objective.

To assess factors associated with adherence to recommended barrier precautions among healthcare workers (HCWs) providing care to critically ill patients with severe acute respiratory syndrome (SARS).

Setting.

Fifteen acute care hospitals in Ontario, Canada

Design.

Retrospective cohort study.

Patients.

All patients with SARS who required intubation during the Toronto SARS outbreak in 2003.

Participants.

HCWS who provided care to or entered the room of a SARS patient during the period from 24 hours before intubation until 4 hours after intubation.

Methods.

Standardized interviews were conducted with eligible HCWs to assess their interactions with the SARS patient, their use of barrier precautions, their practices for removing personal protective equipment, and the infection control training they received.

Results.

Of 879 eligible HCWs, 795 (90%) participated. In multivariate analysis, the following predictors of consistent adherence to recommended barrier precautions were identified: recognition of the patient as a SARS case (odds ratio [OR], 2.5 [95% confidence interval {CI}, 1.5-4.5); recent infection control training (OR for interactive training, 2.7 [95% CI, 1.7-4.4]; OR for passive training, 1.7 [95% CI, 1.0-3.0]), and working in a SARS unit (OR, 4.0 [95% CI, 1.8-8.9]) or intensive care unit (OR, 4.3 [95% CI, 2.0-9.0]). Two factors were associated with significantly lower rates of consistent adherence: the provision of care for patients with higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores (OR for score APACHE II of 20 or greater, 0.4 [95% CI, 0.28-0.68]) and work on shifts that required more frequent room entry (OR for 6 or more entries per shift, 0.5 [95% CI, 0.32-0.86]).

Conclusions.

There were significant deficits in knowledge about self-protection that were partially corrected by education programs during the SARS outbreak. HCWs' adherence to self-protection guidelines was most closely associated with whether they provided care to patients who had received a definite diagnosis of SARS.

Psychological and physical functioning difficulties associated with complex activity limitations among U.S. adults

BACKGROUND

There is limited research that assesses psychological functioning categorically as a predictor of complex activity limitations either alone or in conjunction with physical functioning.

OBJECTIVES

This paper assesses the impact of psychological and/or physical functioning difficulties as predictors of complex activity limitations among U.S. adults, using data from a national survey.

METHODS

Data come from the 2006-2010 National Health Interview Survey among U.S. adults 18 or older (n = 124,337). We developed a combined physical/psychological exposure variable with six categories: 1) no/low psychological distress (LPD) and absence of physical functioning difficulties, 2) moderate psychological distress (MPD) only, 3) serious psychological distress (SPD) only, 4) physical functioning difficulty only, 5) MPD and physical functioning difficulties, and 6) SPD and physical functioning difficulties. Selected complex activity limitations include daily living, social and work limitations.

RESULTS

Compared to adults with LPD and absence of physical functioning difficulties, the results demonstrated a clear and significant gradient of increasing risk of complex activity limitations beginning with MPD only, SPD only, physical functioning difficulty only, both MPD and physical functioning difficulties, and SPD and physical functioning difficulties.

CONCLUSIONS

The data suggest a stronger risk of complex activity limitations when increasing psychological functioning difficulties coexist with physical functioning difficulties, leading to potential interference with a person's ability to accomplish major life activities measured in this study. The sizeable contribution of psychological distress to the prevalence of basic actions difficulty implies that the mental health component of functional limitations is important in the overall assessment of health and well-being.

Interim estimates of 2013/14 influenza clinical severity and vaccine effectiveness in the prevention of laboratory-confirmed influenza-related hospitalisation, Canada, February 2014

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Genetic susceptibility to West Nile virus and dengue

This article focuses on the host genetic predisposition to 2 viruses, West Nile virus and dengue virus, which belong to the genus Flavivirus. Although by definition these viruses have shared characteristics (e.g. similar size, single stranded, RNA viruses, both transmitted by the bite from an infected mosquito), they differ greatly in epidemiology and clinical manifestations. The text below not only summarizes the genetic factors that predispose to complications of these 2 important flaviviruses, but also illustrates the challenges in determining the genomic basis for complications to these viruses.

Methods to improve international comparability of census and survey measures of disability

PURPOSE

To describe the methods used by the Washington Group on Disability Statistics (WG) to develop internationally comparable questions on disability that can be used worldwide.

METHOD

The WG approach to developing disability measures included careful consideration of the theoretical and conceptual issues associated with disability, translating disability concepts into measurement tools, and mixed-method evaluations of the proposed questions using both cognitive and field interviewing methodologies.

RESULTS

Disability is a complex construct the measurement of which presents considerable challenges for survey methodologists. The Washington Group on Disability Statistics (WG), a UN Statistical Commission sponsored city group, was established to address the methodological and measurement challenges that have characterized disability statistics and to develop questions for use worldwide that will provide comparable, valid and reliable disability statistics. The WG used a variety of methods to meet these objectives and has finalized a short set disability measure for use in censuses worldwide.

CONCLUSIONS

The methodologies adopted by the WG have resulted in question sets that greatly improve the international comparability of disability statistics and will advance our understanding of disability worldwide.

Functional difficulties among school-aged children: United States, 2001-2007

OBJECTIVE

This report presents estimates of basic actions difficulty, which includes difficulties related to sensory, motor, cognitive, and emotional or behavioral functioning, in U.S. children aged 5-17 years based on questions from the National Health Interview Survey (NHIS). Selected estimates are shown for the educational and health care service use of children with and without basic actions difficulty.

METHODS

Estimates of basic actions difficulty were derived from the Family Core and the Sample Child Core questionnaires of the 2001-2007 NHIS. Estimates were generated and compared using SUDAAN, a statistical package that adjusts for the complex sample design of NHIS.

RESULTS

Approximately 18% of children aged 5-17 had basic actions difficulty in one or more of the following domains of functioning: sensory, movement, cognitive, or emotional or behavioral. The percentage of children with difficulty in specific domains varied: 3% had sensory difficulty, 2% movement difficulty, 9% cognitive difficulty, and 10% emotional or behavioral difficulty. From 2001 through 2007, the percentage of children aged 5-17 with basic actions difficulty remained stable at about 18%. Children with and without basic actions difficulty differed greatly in their use of both educational and health care services. One-third of children with basic actions difficulty used special education services compared with 2% of children without basic actions difficulty. A substantially higher percentage of children with basic actions difficulty used health care services, including mental health care, other types of therapy, and prescription medication, than children without basic actions difficulty.

Exploring ICF components in a survey among Xhosa speakers in Eastern & Western Cape, South Africa

PURPOSE

To contribute to the testing and development of the ICF model by exploring the relationship between activity limitations, participation restrictions and environmental barriers.

METHOD

Structured questionnaire-based interviews were carried out among a convenience sample of 950 households counting 4917 individuals in Eastern and Western Cape, South Africa. Approximately half of the households had at least one individual with disability, while the other half represented controls in the study. Activity limitations, participation restrictions and environmental barriers were operationalized by means of questions drawn directly from the ICF checklist.

RESULTS

Principal component analyses supported a four-component solution for the activity and participation variables, and a two-component solution for the barrier variables. Scales for each sub-component were produced by adding the individual items under each sub-component. Male respondents are more restricted than females when it comes to social activities, individual care, education and mobility barriers. While respondents in Western Cape scored higher (more limitations and restrictions) on the activity and participation sub-scales individual care, daily activities and education, Eastern Cape respondents scored higher on both the environmental barrier sub-scales.

CONCLUSIONS

A viable structure of sub-components under the broader ICF concepts has been demonstrated. The study has provided some support to viewing activity limitations and participation restrictions as two independent dimensions, but also invites further studies and refinement of the model.

Variation in mortality rates among long-term care facilities for residents with lower respiratory tract infection

OBJECTIVE

To identify variables contributing to interfacility differences in mortality among residents of long-term care facilities who have lower respiratory tract infection.

DESIGN

Multicenter, prospective, 1-year observational study.

SETTING

Twenty-one long-term care facilities in 4 geographic areas of Canada.

PARTICIPANTS

Residents of long-term care facilities prescribed antimicrobials for treatment of lower respiratory tract infection.

METHODS

Mortality rates were calculated for 3 definitions of lower respiratory tract infection: episodes with a clinical or radiographic diagnosis and treated with antimicrobials (definition 1); episodes with a physician diagnosis of pneumonia (definition 2); and episodes with chest radiography findings consistent with pneumonia (definition 3). Multilevel modeling was used to evaluate variables describing premorbid resident status, clinical presentation, management, and facility characteristics. Multivariable models were developed to identify independent predictors of mortality and determine whether facility-level variables remained independently associated with mortality rate after incorporation of individual-level variables.

RESULTS

Facility mortality rates varied from 0% to 17.8% for definition 1, from 0% to 47.1% for definition 2, and from 0% to 37.5% for definition 3. There were significant differences in mortality rate depending on which definition was used; for definitions 1 and 2, there were significant differences in mortality rate across facilities. Poorer premorbid resident status and a more severe presentation remained independent predictors of mortality in the multivariable analysis. There were also significantly increased mortality rates for episodes in which a fluoroquinolone was prescribed for initial treatment. For definitions 1 and 3, facility-level variables remained independently associated with mortality rate in the final multivariable model.

CONCLUSIONS

Rates of mortality due to lower respiratory tract infection varied among long-term care facilities and differed within a facility, depending on the definition applied. Variables describing premorbid resident status, severity of presentation, and management did not fully explain the variation in mortality rate. Some facility-level variables remained independent predictors of mortality.

Population-based prevalence of CDKN2A and CDK4 mutations in patients with multiple primary melanomas

The presence of multiple primary cutaneous melanomas (MPM) has been advocated as guidance to identifying melanoma families. Frequencies of CDKN2A mutations in materials of sporadic MPM cases from pigmented lesion clinics vary between 8 and 15%. Patients with MPM have therefore been regarded as good candidates for CDKN2A mutational screening. We describe a population-based study where all persons in Norway diagnosed with MPM between 1953 and 2004 (n = 738 alive per April 2004) were invited to participate. Three-hundred-and-ninety patients (52.8%) responded confidentially. Mutations in CDKN2A were found in 6.9% of the respondents. Eighty-one MPM patients (20.8%) reported that they belonged to melanoma families, and 17 (21.0%) of these harboured a CDKN2A mutation, compared to 3.2% of the nonfamilial cases. The probability of finding a CDKN2A mutation increased when the patients had three or more melanomas, or a young age of onset of first melanoma. We identified five novel CDKN2A variants (Ala57Gly, Pro81Arg, Ala118Val, Leu130Val, and Arg131Pro) and four that previously have been reported in melanoma families (Glu27X, Met53Ile, Arg87Trp, and Ala127Pro). A large deletion (g.13623_23772del10150) encompassing exon 1alpha and the 5' part of exon 2 was detected in six patients with a family history of melanoma. Three patients, belonging to the same family, had the CDK4 Arg24His mutation. The frequency of CDKN2A mutations was lower than previously reported in other studies, an observation which probably is due to the population-based design of our study.

Narrowband UVB therapy for vitiligo: does the repigmentation last?

BACKGROUND

Since 1997, a number of trials have shown promising results in treating generalized vitiligo with narrowband ultraviolet B (UVB) both in adults and children. However, there is little knowledge concerning the duration and permanency of the treatment-induced repigmentation.

OBJECTIVE

Our main objective was to perform a follow-up trial of successfully treated patients receiving narrowband UVB for generalized vitiligo.

METHODS

We have investigated to what degree the treatment-induced repigmentation remains stable for up to 2 years post-treatment. We performed an initial open trial including 31 patients with generalized vitiligo. They received narrowband UVB thrice weekly for up to 12 months. Patients experiencing > 75% repigmentation were defined responders and were included in the follow-up trial. Responders were followed every 6 months for up to 2 years after cessation of treatment. We observed the pigmentation status and registered any changes indicating loss of pigmentation and relapse.

RESULTS

Eleven of the 31 treated patients were included in the follow-up trial. Six patients had relapse and five patients had stable response 24 months after cessation of treatment. Four out of six relapses were within 6 months post-treatment.

CONCLUSION

In our study population of 31 patients with generalized vitiligo, five patients (16%) experienced > 75% stable repigmentation 2 years after cessation of a treatment programme of up to 1 years narrowband UVB therapy.

Point prevalence survey for healthcare-associated infections within Canadian adult acute-care hospitals☆☆☆

A survey of adult patients 19 years of age and older was conducted in February 2002 in hospitals across Canada to estimate the prevalence of healthcare-associated infections (HAIs). A total of 5750 adults were surveyed; 601 of these had 667 HAIs, giving a prevalence of 10.5% infected patients and 11.6% HAIs. Urinary tract infections (UTI) were the most frequent HAI, shown by 194 (3.4%) of the patients surveyed. Pneumonia was found in 175 (3.0%) of the patients, surgical site infections (SSI) in 146 (2.5%), bloodstream infections (BSI) in 93 (1.6%) and Clostridium difficile-associated diarrhoea (CDAD) in 59 (1%). In this first national point prevalence study in Canada, the prevalence of HAI was found to be similar to that reported by other industrialized countries.

Mental health in deaf adults: symptoms of anxiety and depression among hearing and deaf individuals

Individuals with disabilities encounter practical and social problems beyond those experienced by nondisabled individuals. This extra burden may in turn increase the risk of developing mental health problems. The objective of this article is to disclose the mental health situation among deaf individuals compared to a control sample of hearing individuals. The analyses are based on two separate Norwegian postal surveys, one among the general population (1995-1997) and one among the deaf population (2001). A shortened version of the Hopkins Symptom Checklist was used to disclose the degree of mental distress among the respondents. Three questions common to the studies were analyzed to determine differences between the two groups. Analyses revealed that the deaf respondents showed significantly more symptoms of mental health problems than the hearing respondents. The results point to the need for focussing more attention on the mental health of deaf children and adults. Society must be made aware of the special risks that deaf children and adults encounter with respect to mental health.

Severity of illness and the use of paracetamol in febrile preschool children; a case simulation study of parents' assessments

OBJECTIVE

Misconceptions and exaggerated fear of fever may divert parents' attention from more predictive symptoms of childhood illness, such as appetite and level of activity. This study aims at exploring how specific predefined characteristics of febrile preschool children affected parents' assessment of the severity of the condition and the perceived need for treatment with paracetamol.

METHODS

Parents judged 24 constructed cases of febrile children with different levels of fever, appetite and activity, occurring at different times of the day. For each case they decided whether the child was moderately or severely ill, and whether or not they would prefer to administer paracetamol. Parents' decision-making was examined by discriminant analyses.

RESULTS

Of 466 invited parents, 267 supplied information about their families and 205 accepted to participate in judging constructed cases of febrile children. A total of 159 parents responded to all cases. When evaluating the severity of the illness, 119 parents (75%) responded to one or more of the four cues describing illness. Only one of four cues was used by 80 parents (67%), and 86 (72%) parents emphasized fever. When deciding to give paracetamol, one or more of four cues was used by 102 parents (64%), while 72 parents (71%) used only one cue, and 92 parents (90%) emphasized fever.

CONCLUSIONS

Parents focus on fever when they evaluate febrile illness and decide whether or not to give paracetamol. Educating parents to focus on their child's level of appetite or activity may improve management, especially when judgement is based on only one or two cues.

Early diagnosis of SARS: lessons from the Toronto SARS outbreak

The clinical presentation of SARS is nonspecific and diagnostic tests do not provide accurate results early in the disease course. Initial diagnosis remains reliant on clinical assessment. To identify features of the clinical assessment that are useful in SARS diagnosis, the exposure status and the prevalence and timing of symptoms, signs, laboratory and radiographic findings were determined for all adult patients admitted with suspected SARS during the Toronto SARS outbreak. Findings were compared between patients with laboratory-confirmed SARS and those in whom SARS was excluded by laboratory or public health investigation. Of 364 cases, 273 (75%) had confirmed SARS, 30 (8%) were excluded, and 61 (17%) remained indeterminate. Among confirmed cases, exposure occurred in the healthcare environment (80%) or in the households of affected patients (17%); community or travel-related cases were rare (<3%). Fever occurred in 97% of patients by the time of admission. Respiratory findings including cough, dyspnea and pulmonary infiltrates evolved later and were present in only 59, 37 and 68% of patients, respectively, at admission. Direct exposure, fever on the first day of illness, and elevated temperature, pulmonary infiltrates, lymphopenia and thrombocytopenia at admission were associated with confirmed cases. Rhinorrhea, sore throat, and an elevated neutrophil count at admission were associated with excluded cases. In the absence of fever or significant exposure, SARS is unlikely. Other clinical, laboratory and radiographic findings further raise or lower the likelihood of SARS and provide a rational basis for estimating the likelihood of SARS and directing initial management.

Accuracy of healthcare worker recall and medical record review for identifying infectious exposures to hospitalized patients

OBJECTIVE

To determine the validity of using healthcare worker (HCW) recall of patient interactions and medical record review for contact tracing in a critical care setting.

DESIGN

Trained observers recorded the interactions of nurses, respiratory therapists, and service assistants with study patients in a medical-surgical intensive care unit. These observers' records were used as the reference standard to test the criterion validity of using HCW recall data or medical record review data to identify exposure characteristics. We assessed the effects of previous quarantine of the HCW (because of possible exposure) and the availability of patients' medical records for use as memory aids on the accuracy of HCW recall.

SETTING

A 10-bed medical-surgical intensive care unit at Mount Sinai Hospital in Toronto, Ontario.

PATIENTS

Thirty-six HCWs observed caring for 16 patients, for a total of 55 healthcare worker shifts.

RESULTS

Recall accuracy was better among HCWs who were provided with patient medical records as memory aids (P<.01). However, HCWs tended to overestimate exposures when they used patient medical records as memory aids. For 6 of 26 procedures or care activities, this tendency to overestimate was statistically significant (P<.05). Most HCWs with true exposures were identified by means of this technique, despite the overestimations. Documentation of the activities of the 4 service assistants could not be found in any of the patients' medical records. Similarly, the interactions between 6 (19%) of 32 other patient-HCW pairs were not recorded in patients' medical records.

CONCLUSIONS

Data collected from follow-up interviews with HCWs in which they are provided with patient medical records as memory aids should be adequate for contact tracing and for determining exposure histories. Neither follow-up interviews nor medical record review alone provide sufficient data for these purposes.

[Treatment of asthma--an analysis of clinical judgment among general practitioners]

BACKGROUND

The asthma patient's symptoms, use of drugs, and peak expiratory flow rates dictate treatment of asthma according to the guidelines. Our aim was to examine which information influenced the decisions of general practitioners.

MATERIAL AND METHODS

Out of 100 general practitioners attending a course on asthma management, 75 responded to several constructed patient cases on asthma treatment. They decided whether or not to give oral steroids in case of an acute exacerbation and judged the quality of pharmacological treatment. Age, symptoms, body temperature, peak expiratory flow measurement and the dose of beta-2 agonists and inhaled steroids varied from patient to patient. Their attitudes to the use of oral steroids and to the usefulness of measuring peak expiratory flow were evaluated.

RESULTS

Among the doctors, 52% evaluated only one characteristic of the patients when deciding upon treatment with oral steroids. The use of drugs was evaluated by one quarter of the doctors when they judged the quality of treatment. Respectively, 81% and 73% were influenced by objective measurements in these decisions. The majority of doctors applied oral steroids and measured peak expiratory flow in asthmatics.

INTERPRETATION

This study indicates that general practitioners focus mainly on measured peak expiratory flow rate. The patient's symptoms ought to be given more consideration in the treatment of asthma. The patient's use of anti-asthmatics is emphasised in guidelines, but was of only limited importance to the doctors in this study.

Small diameter melanoma: a follow-up of the Norwegian Melanoma Project

BACKGROUND

Melanoma prognosis is dependent upon early recognition and treatment. There is a need for good clinical guidelines that focus on the early signs of melanoma. The ABCD (asymmetry, border, colour and diameter) rule states that most melanomas are more than 6 mm in diameter. Critics crave a modification, arguing that small diameter melanomas are not infrequent.

OBJECTIVES

The aim of the present study was to describe the frequency and prognosis of melanomas less than 7 mm in a clinical setting.

METHODS

The Norwegian Melanoma Project was conducted as a multicentre, prospective study with inclusion criteria. Patients were recruited from five dermatological departments in Norway from 1990 to 1993.

RESULTS

The frequency of small melanomas was 11.4% (18/158). One-third was in situ melanoma, the rest invasive with a median thickness of 0.8 mm. Four small melanomas were T2 lesions, with a Breslow thickness of more than 1 mm. One nodular T2 melanoma recurred locally 2 years after diagnosis and the patient died of distant metastasis only months later.

CONCLUSIONS

The ABCD rule remains a practical guide for early recognition of melanoma. Clinicians must be aware of its limitations.

Is there a specific relationship between childhood sexual and physical abuse and repeated suicidal behavior?

OBJECTIVE

Studies show that childhood sexual and physical abuse predict repeated suicide attempts and self-mutilation. Little is known about the importance of sexual and physical abuse when compared to other severe childhood adversities with respect to chronic suicidal behavior.

METHOD

Seventy-four subjects, 65% of whom were women, consecutively admitted to a general hospital after having made a suicide attempt, were interviewed as part of the intake interview about prior suicide attempts and self-mutilation and received DSM-IV diagnoses. Sexual abuse, physical abuse, neglect, antipathy from parents, loss of parents, and severe discord in the family before the age of 18, were covered by the Childhood Experience of Care and Abuse (CECA) interview schedule.

RESULTS

The prevalence of severe sexual abuse was 35%, severe physical abuse 18%, neglect 27%, antipathy 34%, loss of caregiver 37% and exposure to family violence 31%. Physical and sexual abuse were independently associated with repeated suicide attempts when controlling for the effects of the other childhood adverse factors. No other childhood adversity was related to chronic suicidal behavior. The odds ratio of exposure to sexual or physical abuse was highest among those who both repeated suicide attempts and self-mutilated.

CONCLUSION

Physical and sexual abuse are significantly and independently associated with repeated suicidal behavior.

Suicidal ideation and attempts in Norwegian police

Studies on suicide among police show inconsistent results, thereby contributing to considerable speculation regarding why police officers commit suicide. The present paper is the first nationwide study on suicidal ideation and attempts among police. 3,272 Norwegian police completed Paykel's Suicidal Feelings in the General Population questionnaire. Lifetime prevalence of specific questionnaire items ranged from 24% for the feeling that life was not worth living, 6.4% for having seriously considered suicide, and 0.7% for attempted suicide. Independent predictors of serious suicidal ideation were marital status, subjective health complaints, reality weakness, anxiety, and depression. Serious suicidal ideation was mainly attributed to personal and family problems.

Molecular epidemiology of invasive Salmonella typhi in southeast Turkey

The objective of this study was to determine the molecular epidemiology of Salmonella typhi isolates from patients with typhoid fever in southeast Turkey and to determine the relationship between the clinical strains and environmental subtypes. Both demographic and clinical data were obtained by chart review and compared to the molecular subtyping results.

Predictors of outcome in patients with tuberculous meningitis

OBJECTIVE

To assess predictors of mortality and neurological sequelae in patients with tuberculous meningitis (TBM).

METHODS

Patients with TBM treated at 12 university hospitals in Turkey between 1985 and 1997 were evaluated using a standardised protocol applied retrospectively. Variables associated with hospital mortality as well as with the presence of neurological sequelae at 6 months were determined using logistic regression models.

RESULTS

Four hundred and thirty-four patients between the ages of 13 and 83 years (mean 33 years) were evaluated. Sixty-eight per cent of these patients presented with Medical Research Council Stage II or III. One hundred and one patients (23.3%) died and 67 (27%) of evaluable survivors had neurological sequelae. In multi-variable analysis, convulsion (OR 3.3, 95%CI 1.2-9.0, P = 0.02), comatose mental status (OR 6.0, 95%CI 3.6-10.2, P = 0.01), and delayed or interrupted treatment (OR 5.1, 95%CI 2.4-11.2, P = 0.01) were shown to be predictors for mortality. The presence of extra-meningeal tuberculosis (OR 2.1, 95%CI 1.1-4.2, P = 0.035), cranial nerve palsy (OR 2.6, 95%CI 1.4-4.2, P = 0.01), hemiparesia/focal weakness (OR 9.3, 95%CI 3.8-22.6, P = 0.01), hemiplegia/multiple neurological deficit (OR 7.1, 95%CI 2.14-23.38, P = 0.01) and drowsiness (OR 4.2, 95%CI 2.04-8.82, P = 0.01) were independent predictors of neurological sequelae at 6 months following hospital discharge.

CONCLUSION

The results of this study emphasise the importance of prompt and uninterrupted anti-tuberculosis therapy for tuberculous meningitis. The presence of seizures or coma on admission to hospital are important predictors for mortality, while the presence of focal neurological signs is a predictor for persistent neurological sequelae in survivors.

Adherence to antibiotic guidelines for pneumonia in chronic-care facilities in Ontario

OBJECTIVES

To evaluate adherence to antibiotic recommendations for the treatment of pneumonia in patients who receive long-term care and to assess outcomes associated with these recommendations.

DESIGN

A prospective cohort study.

SETTING

Twenty-two facilities that provide long-term care in southern Ontario.

PARTICIPANTS

Older adults treated with antibiotics for a presumptive diagnosis of pneumonia and those with radiologically confirmed pneumonia

METHODS

Over a 12-month period, older patients who were treated with antibiotics for presumptive pneumonia were prospectively identified. A random sample of these antibiotic courses (646 courses in 638 patients) was reviewed using a standardized data collection form, and demographic and clinical data were collected. Antibiotic courses were classified according to Canadian and American Thoracic Society antibiotic recommendations for pneumonia. In patients with radiologically confirmed pneumonia, the effect of adherence to these recommendations on mortality and persistence of symptoms was assessed.

RESULTS

Only 27.6% (178 of 646) of antibiotic prescriptions evaluated met antibiotic recommendations for nursing-home-acquired pneumonia, and the proportion meeting these varied greatly by facility, ranging from 0% to 53% (median 31%). For patients with radiologically confirmed pneumonia, age (adjusted odds ratio [OR] 1.6, 95% confidence interval [CI] 1.0-2.4, per increase in 10 yr, p = 0.02), sex (adjusted OR 3.0, 95% CI 1.1-8.0, p = 0.03), and adherence to recommended antibiotics (OR 3.0, 95% CI 1.3-7.2, p = 0.01) were associated with death. Adherence to the recommended antibiotics was also associated with adverse reactions, which occurred in 10% of prescriptions meeting the recommendations (OR 2.4, 95% CI 1.3-4.6, p = 0.01).

CONCLUSIONS

Adherence to recommended guidelines for antibiotic treatment was low and highly variable among study facilities. Use of recommended antibiotic regimens was associated with increased adverse events and worse outcomes in patients with radiologically confirmed pneumonia.

Quinolone use as a risk factor for nosocomial Clostridium difficile-associated diarrhea

OBJECTIVE

To determine modifiable risk factors for nosocomial Clostridium difficile-associated diarrhea (CDAD).

DESIGN

Case-control study.

SETTING

300-bed tertiary-care hospital.

PARTICIPANTS

Hospital inpatients present during the 3-month study period.

METHODS

Case-patients identified with nosocomial CDAD over the study period were compared to two sets of control patients: inpatients matched by age, gender, and date of admission; and inpatients matched by duration of hospital stay. Variables including demographic data, comorbid illnesses, antibiotic exposure, and use of gastrointestinal medications were assessed for case- and control-patients. Conditional logistic regression was performed to identify risk factors for nosocomial CDAD.

RESULTS

27 case-patients were identified and were compared to the two sets of controls (1:1 match for each comparison set). For the first set of controls, use of ciprofloxacin (odds ratio [OR], 5.5; 95% confidence interval [CI 95], 1.2-24.8; P=.03) was the only variable that remained significant in the multivariable model. For the second set of controls, prior exposure to cephalosporins (OR, 6.7; CI 95, 1.3-33.7; P=.02) and to ciprofloxacin (OR, 9.5; CI 95, 1.01-88.4; P=.05) were kept in the final model.

CONCLUSIONS

Along with cephalosporins, prior quinolone use predisposed hospitalized patients to nosocomial CDAD. Quinolones should be used judiciously in acute-care hospitals, particularly in those where CDAD is endemic.

The role of stem cells in midgut growth and regeneration

The Manduca sexta (L.) [Lepidoptera: Sphingidae] and Heliothis virescens (F.) [Lepidoptera: Noctuidae] midguts consist of a pseudostratified epithelium surrounded by striated muscle and tracheae. This epithelium contains goblet, columnar, and basal stem cells. The stem cells are critically important in that they are capable of massive proliferation and differentiation. This growth results in a fourfold enlargement of the midgut at each larval molt. The stem cells are also responsible for limited cell replacement during repair. While the characteristics of the stem cell population vary over the course of an instar, stem cells collected early in an instar and those collected late can start in vitro cultures. Cultures of larval stem, goblet, and columnar cells survive in vitro for several mo through proliferation and differentiation of the stem cells. One of the two polypeptide differentiation factors which have been identified and characterized from the culture medium has now been shown to be present in midgut in vivo. Thus the ability to examine lepidopteran midgut stem cell growth in vitro and in vivo is proving to be effective in determining the basic features of stem cell action and regulation.