COVID-19-Associated Deaths After SARS-CoV-2 Infection During Pregnancy - Mississippi, March 1, 2020-October 6, 2021.

Pregnant and recently pregnant women are at increased risk for severe illness and death from COVID-19 compared with women who are not pregnant or were not recently pregnant (1,2). CDC recommends COVID-19 vaccination for women who are pregnant, recently pregnant, trying to become pregnant, or might become pregnant in the future.*,† This report describes 15 COVID-19-associated deaths after infection with SARS-CoV-2 (the virus that causes COVID-19) during pregnancy in Mississippi during March 1, 2020-October 6, 2021.

Symptom Level Associations Between Attention-Deficit Hyperactivity Disorder and School Performance.

Attention-deficit hyperactivity disorder (ADHD) is associated with reduced school performance. To determine which ADHD symptoms and subtypes have the strongest association, we used type and frequency of symptoms on the 2014 National Survey of the Diagnosis and Treatment of ADHD and Tourette Syndrome (NS-DATA) to create symptom scores for inattention and hyperactivity-impulsivity and define subtypes (ADHD-Inattentive [ADHD-I], ADHD-Hyperactive-Impulsive, ADHD-Combined [ADHD-C]). Regression methods were used to examine associations between symptoms and subtype and a composite measure of school performance. Children with ADHD-C and ADHD-I had higher adjusted odds of having reduced overall school performance (ADHD-C = 5.8, 95% confidence interval [CI] = 3.1-10.9; ADHD-I = 5.5, 95% CI = 3.1-10.1) compared with children without ADHD. All inattentive symptoms were significantly related to reduced school performance in reading, writing, and handwriting, while 6 of 9 symptoms were significantly associated in mathematics. Children with ADHD-I were significantly more likely than children with other ADHD subtypes to receive a school-based Individualized Education Program or 504 Plan. ADHD-I symptoms may be broadly linked to reduced school performance.

Standardization of State Definitions for Neonatal Abstinence Syndrome Surveillance and the Opioid Crisis.

Rates of neonatal abstinence syndrome (NAS) have increased fivefold in the past decade. To address this expanding and complex issue, state public health agencies have addressed the opioid crisis affecting newborns in diverse ways, leading to a variety of methods to quantify the burden of NAS.In an effort to understand this variability, we summarized clinical case and surveillance definitions used across jurisdictions in the United States. We confirmed that the rapid progression of the nation's opioid crisis resulted in heterogeneous processes for identifying NAS. Current clinical case definitions use different combinations of clinician-observed signs of withdrawal and evidence of perinatal substance exposure. Similarly, there is discordance in diagnosis codes used in surveillance definitions. This variability makes it difficult to produce comparable estimates across jurisdictions, which are needed to effectively guide public health strategies and interventions.Although standardization is complicated, consistent NAS definitions would increase comparability of NAS estimates across the nation and would better guide prevention and treatment efforts for women and their infants.

Relationship of Adverse Family Experiences to Resilience and School Engagement Among Vermont Youth.

INTRODUCTION: Adverse childhood experiences (ACEs) are associated with a range of health outcomes and risk behaviors. In 2011-2012, the National Survey of Children's Health (NSCH) included questions about adverse family experiences (AFEs). AFE survey questions are similar to ACE questions, except there are no questions about emotional/physical/sexual trauma, and questions are asked of parents rather than children. Although the relationship between ACEs and work/school absenteeism has been studied, the relationships between AFEs of school-aged children, school performance, and buffering behaviors have not been explored in depth. METHODS: We examined AFEs and measures of resilience and school engagement among 1330 Vermont children (6-17 years) included in the NSCH, using descriptive, bivariate, and multivariable analyses. RESULTS: The most prevalent AFEs were divorce/separation of parents; family income hardship; substance use problems; and mental illness, suicidality, or severe depression. Adjusting for sex, age, special health care needs, poverty level, and maternal physical/mental-emotional health status, children who had three or more AFEs had lower odds of completing all required homework [adjusted odds ratio (AOR) 3.3, 95% confidence interval (CI) 1.7-6.3] and higher odds of failing to exhibit resilience (AOR 2.1, 95% CI 1.2-3.8), compared to children having no AFEs. DISCUSSION: Children with three or more AFEs had difficulty engaging in school and completing homework, though poor outcomes were buffered when children showed resilience. Parents, school-based mental health professionals, and teachers could help identify children who may be less resilient and have difficulties completing homework assignments. Preventive approaches to children's emotional problems (e.g., promoting family health, using family-based approaches to treat emotional/behavioral problems) could be applied in schools and communities to foster resilience and improve school engagement of children.

Application of a Mixed Methods Approach to Identify Community-Level Solutions to Decrease Racial Disparities in Infant Mortality.

Objectives: This study aimed to identify community-level actions to decrease racial disparities in infant mortality (IM). Design: Six urban multidisciplinary teams generated ideas for decreasing racial disparities in IM using a mixed methods concept mapping approach. Participants rated each idea as to its necessity and action potential and grouped ideas by theme. A cluster analysis produced a series of visual representations, showing relationships between the identified actions and the clustering of actions into themes. Multidimensional scaling techniques were used to produce analyses describing the necessity of and action potential for implementing the proposed ideas. Participants identified actions communities could take to decrease racial disparities in IM and suggested applications of the knowledge gained from the mapping process. Results: Participants produced a total of 128 actions, within 11 thematic clusters, for decreasing racial disparities in IM. The thematic clusters contained a range of elements designed to promote knowledge and understanding of the relationship between health and racism; improve educational systems and community opportunities; facilitate community-driven health promotion, marketing, and research; improve health services for women; address physical and social environments that impact community health; prioritize resource allocation of community-based services; institutionalize strategies that promote equity across all systems; and create and support legislation and policies that address social determinants of health. Correlation coefficients of the clusters ranged from 0.17 to 0.90. Average necessity ratings ranged from 2.17 to 3.73; average action potential ratings ranged from 1.64 to 3.61. Conclusion: Findings suggest that thematic clusters with high action potential usually represented ongoing community activities or actions communities could easily initiate. Community size, existing programs, partnerships, policies, and influential advocates were among the factors cited affecting feasibility of implementation. Clusters with lower action potential require broader, longer term, policy, institutional or system-wide changes, and significant resources. High necessity clusters often contained actions perceived as essential for change, but sometimes outside of a community's control. Participants identified a number of practical actions that were considered to hold potential for individual, community, and institutional changes which could result in decreasing racial disparities in IM.

Associations between neighborhood characteristics and physical activity among youth within rural-urban commuting areas in the US.

The association among rural-urban communities, neighborhood characteristics, and youth physical activity is inconsistent in the literature. We used data from the 2007 National Survey of Children's Health, for youth aged 10-17 years (n = 45,392), to examine the association between physical activity and neighborhood characteristics, after adjusting for known confounders. We also examined the association between physical activity and neighborhood characteristics within seven levels of Rural-Urban Commuting Areas (RUCAs) that depict a continuum from isolated rural to dense urban communities. Attainment of a minimum physical activity level differed by RUCA (P = 0.0004). In adjusted, RUCA-specific models, the presence of parks was associated with attaining a minimum physical activity level in only one of the seven RUCAs (adjusted odds ratio: 3.49; 95 % confidence interval: 1.55, 7.84). This analysis identified no association between youths' minimum physical activity attainment and neighborhood characteristics in unstratified models; and, RUCA-specific models showed little heterogeneity by rural-urban community type. Although this analysis found little association between youth physical activity and neighborhood characteristics, the findings could reflect the crude categorization of the neighborhood amenities (sidewalks, parks, recreation centers) and detracting elements (litter, dilapidated housing, vandalism) and suggests that simple measurement of the presence of an amenity or detracting element is insufficient for determining potential associations with reaching minimum levels of physical activity. By exploring neighborhood characteristics and features of neighborhood amenities within the context of well-defined community types, like RUCAs, we can better understand how and why these factors contribute to different levels of youth physical activity.

Building leadership skills and promoting workforce development: evaluation data collected from public health professionals in the field of maternal and child health.

Professional development, including training and leadership skill building, is important for maternal and child health (MCH) epidemiologists. Current workforce development and training opportunities vary, but lack an emphasis on linking leadership competencies with MCH epidemiology. This paper describes efforts at the annual MCH Epidemiology Conference (the "Conference") to promote leadership activities and workforce development, and recommendations to enhance professional development. An evaluation of attendee opinions on Conference workforce development activities was conducted during the 2009 and 2010 Conferences (70 and 66 % response rates, respectively). Frequencies and percentages were calculated overall and by attendee profession. Qualitative responses to questions regarding workforce and professional development were classified by theme in 2009, and a categorical question was developed for the 2010 evaluation. A combined 38 % of Conference attendees in 2009 and 2010 were MCH epidemiologists and 62 % were other MCH professionals. Attendees recommended more support and access to training, mentoring, and resources including job opportunities. Continuing education (41 %), special knowledge and skills-building training (51 %), and development of online resources for training (57 %) were highly recommended by attendees. Career (47 %) and leadership (49 %) mentoring by senior-level professionals in the field were also highly recommended. Promotion of leadership can be achieved by integrating the concept of leadership into the Conference itself; by publishing and disseminating MCH epidemiologic research in scientific, program, and policy settings; and by communicating the importance of epidemiologic findings to stakeholders and other non-scientific audiences.

Association of residential mobility with child health: an analysis of the 2007 National Survey of Children's Health.

To describe the association of residential mobility with child health. We conducted descriptive, bivariate, and multivariable analyses of data from 63,131 children, 6-17 years, from the 2007 National Survey of Children's Health. Logistic regression was used to explore the association of residential mobility with child health and measures of well-being. Analyses were carried out using SAS-callable SUDAAN to appropriately weight estimates and adjust for the complex sampling design. After adjusting for age, race/ethnicity, presence of a special health care need, family structure, parental education, poverty level, and health insurance status, children who moved ≥ 3 times were more likely to have poorer reported overall physical (AOR 1.21 [95 %CI: 1.01-1.46]) and oral health status (AOR 1.31 [95 % CI: 1.15-1.49]), and ≥ 1 moderate/severe chronic conditions (AOR 1.40 [95 % CI: 1.19-1.65]) than children who had no lifetime moves. When compared to children who had never moved, children who moved ≥ 3 times were more likely to be uninsured/have periods of no coverage (AOR 1.35; 95 % CI: 0.98-1.87) and lack a medical home (AOR 1.16, 95 % CI: 1.04-1.31). None of the outcomes were statistically significant for children who moved fewer than 3 times. Clinicians need to be aware that children who move frequently may lack stable medical homes and consistent coverage increasing their risk of poor health outcomes and aggravation of mild or underlying chronic conditions. Public health systems could provide the necessary link between parents and clinicians to ensure that continuous, coordinated care is established for children who move frequently.

Integrated approaches to improve birth outcomes: perinatal periods of risk, infant mortality review, and the Los Angeles Mommy and Baby Project.

This article provides an example of how Perinatal Periods of Risk (PPOR) can provide a framework and offer analytic methods that move communities to productive action to address infant mortality. Between 1999 and 2002, the infant mortality rate in the Antelope Valley region of Los Angeles County increased from 5.0 to 10.6 per 1,000 live births. Of particular concern, infant mortality among African Americans in the Antelope Valley rose from 11.0 per 1,000 live births (7 cases) in 1999 to 32.7 per 1,000 live births (27 cases) in 2002. In response, the Los Angeles County Department of Public Health, Maternal, Child, and Adolescent Health Programs partnered with a community task force to develop an action plan to address the issue. Three stages of the PPOR approach were used: (1) Assuring Readiness; (2) Data and Assessment, which included: (a) Using 2002 vital records to identify areas with the highest excess rates of feto-infant mortality (Phase 1 PPOR), and (b) Implementing Infant Mortality Review (IMR) and the Los Angeles Mommy and Baby (LAMB) Project, a population-based study to identify potential factors associated with adverse birth outcomes. (Phase 2 PPOR); and (3) Strategy and Planning, to develop strategic actions for targeted prevention. A description of stakeholders' commitments to improve birth outcomes and monitor infant mortality is also given. The Antelope Valley community was engaged and ready to investigate the local rise in infant mortality. Phase 1 PPOR analysis identified Maternal Health/Prematurity and Infant Health as the most important periods of risk for further investigation and potential intervention. During the Phase 2 PPOR analyses, IMR found a significant proportion of mothers with previous fetal loss (45%) or low birth weight/preterm (LBW/PT) birth, late prenatal care (39%), maternal infections (47%), and infant safety issues (21%). After adjusting for potential confounders (maternal age, race, education level, and marital status), the LAMB case-control study (279 controls, 87 cases) identified additional factors associated with LBW births: high blood pressure before and during pregnancy, pregnancy weight gain falling outside of the recommended range, smoking during pregnancy, and feeling unhappy during pregnancy. PT birth was significantly associated with having a previous LBW/PT birth, not taking multivitamins before pregnancy, and feeling unhappy during pregnancy. In response to these findings, community stakeholders gathered to develop strategic actions for targeted prevention to address infant mortality. Subsequently, key funders infused resources into the community, resulting in expanded case management of high-risk women, increased family planning services and local resources, better training for nurses, and public health initiatives to increase awareness of infant safety. Community readiness, mobilization, and alignment in addressing a public health concern in Los Angeles County enabled the integration of PPOR analytic methods into the established IMR structure and [the design and implementation of a population-based l study (LAMB)] to monitor the factors associated with adverse birth outcomes. PPOR proved an effective approach for identifying risk and social factors of greatest concern, the magnitude of the problem, and mobilizing community action to improve infant mortality in the Antelope Valley.

Mapping the prevalence of malaria in rural Papua New Guinea using a geographic information system.

The application of geographic information systems (GIS) technology to malaria surveillance presents an opportunity for focusing intervention and prevention activities in the areas most affected. We used GIS technology to map the prevalence of malaria in the Wosera Health and Demographic Surveillance Site, East Sepik Province, Papua New Guinea (PNG). Malaria, demographic and GIS data collected between 2001 and 2003 were aggregated and analysed. This was achieved by geo-coding or linking the prevalence and demographic data to the village location. All GIS manipulation and cartographic displays were performed in MapInfo. The results suggest that malaria is endemic with high prevalence as observed across the 3 surveyed years. The optimized implementation of GIS can be of tremendous benefit in the fight against malaria and other public health challenges in PNG.

What factors are associated with state performance on provision of transition services to CSHCN?

OBJECTIVE: To examine whether individual, condition-related, and system-related characteristics are associated with state performance (high, medium, low) on the provision of transition services to children with special health care needs (CSHCN). METHODS: We conducted descriptive, bivariate, and multivariable analyses of 16876 children aged 12 to 17 years by using data from the 2005-2006 National Survey of Children With Special Health Care Needs. Polytomous logistic regression was used to compare the characteristics of CSHCN residing within high-, medium-, and low-performance states, with low-performance states serving as the reference group. RESULTS: Compared with non-Hispanic white CSHCN, Hispanic (adjusted odds ratio [aOR]: 0.25 [95% confidence interval (CI): 0.17-0.37]) and non-Hispanic black (aOR: 0.44 [95% CI: 0.30-0.62]) CSHCN were less likely to reside in a high-performance than in a low-performance state. Compared with CSHCN who had a medical home or adequate insurance coverage, CSHCN who did not have a medical home or adequate insurance coverage were less likely to reside in a high-performance than in a low-performance state (aOR: 0.73 [95% CI: 0.57-0.95]; aOR: 0.73 [95% CI: 0.58-0.93], respectively). CONCLUSIONS: Key factors found to be important in a state's performance on provision of transition services to CSHCN were race/ethnicity and having a medical home and adequate insurance coverage. Efforts to support the Maternal and Child Health Bureau's integration of system-level factors in quality-improvement activities, particularly establishing a medical home and attaining and maintaining adequate insurance, are likely to help states improve their performance on provision of transition services.

Does rural residence affect access to prenatal care in Oregon?

CONTEXT: Identifying how maternal residential location affects late initiation of prenatal care is important for policy planning and allocation of resources for intervention. PURPOSE: To determine how rural residence and other social and demographic characteristics affect late initiation of prenatal care, and how residence status is associated with self-reported barriers to accessing early prenatal care. METHODS: This observational study used data from the 2003 Oregon Pregnancy Risk Assessment Monitoring System (PRAMS) (N = 1,508), with late initiation of prenatal care (after the first trimester) as the primary outcome. We used Rural-Urban Commuting Area (RUCA) codes to categorize maternal residence as urban, large rural, or small/isolated rural. Multivariate logistic regression was used to evaluate whether category of residence was associated with late initiation of prenatal care after adjusting for other maternal factors. Association between categories of barriers to prenatal care and maternal category of residence were determined using the Cochran-Mantel-Haenszel test of association. FINDINGS: We found no significant association between residence category and late initiation of prenatal care, or residence category and barriers to prenatal care initiation. Urban women tended to be over age 34 or nonwhite. Women from large rural areas were more likely to be younger than 18 years, unmarried, and have an unintended pregnancy. Women from small rural areas were more likely to use tobacco during pregnancy. CONCLUSIONS: Maternal residence category is not associated with late initiation of prenatal care or with barriers to initiation of prenatal care. Differences in maternal risk profiles by location suggest possible new foci for programs, such as tobacco education in small rural areas.

Impact of hospital policies on breastfeeding outcomes.

OBJECTIVE: The objective of this study was to explore the association between the Ten Steps of the Baby Friendly Hospital Initiative (BFHI) of the World Health Organization (Geneva, Switzerland) and breastfeeding at 2 days and 2 weeks. METHODS: A 65-question institutional survey assessing compliance with the Ten Steps was used to determine an overall breastfeeding Support Score for each of Oregon's 57 birthing hospitals. Hospital breastfeeding outcomes were obtained from the newborn metabolic screening forms. RESULTS: Hospitals' overall breastfeeding Support Scores ranged from 49.4 to 98.2 out of a possible total score of 100. Hospital compliance with individual Steps ranged from 5.3% for Step 2 (staff training) to 93% for Step 4 (helping with breastfeeding initiation) and Step 8 (encouraging feeding on demand). After controlling for institutional differences (by multivariate linear regression) we found that increases in overall hospital breastfeeding Support Scores were associated with increases in breastfeeding percentage at 2 days (p = 0.021) and at 2 weeks postpartum (p = 0.011). In analyzing each Step individually, however, only the presence of a written hospital policy was independently associated with breastfeeding percent (p = 0.028). CONCLUSIONS: This institutional-level evaluation corroborates previous findings demonstrating that increased implementation of the Ten Steps is associated with increased breastfeeding. Further, it suggests that hospitals with comprehensive breastfeeding policies are likely to have better breastfeeding support services and better breastfeeding outcomes. Hospitals may consider using these results to prioritize breastfeeding support services through development of hospital breastfeeding policies and to utilize institutional surveys as a component of breastfeeding quality improvement initiatives.

Marketing infant formula through hospitals: the impact of commercial hospital discharge packs on breastfeeding.

OBJECTIVES: Commercial hospital discharge packs are commonly given to new mothers at the time of newborn hospital discharge. We evaluated the relationship between exclusive breastfeeding and the receipt of commercial hospital discharge packs in a population-based sample of Oregon women who initiated breastfeeding before newborn hospital discharge. METHODS: We analyzed data from the 2000 and 2001 Oregon Pregnancy Risk Assessment Monitoring System (PRAMS), a population-based survey of postpartum women (n=3895; unweighted response rate=71.6%). RESULTS: Among women who had initiated breastfeeding, 66.8% reported having received commercial hospital discharge packs. We found that women who received these packs were more likely to exclusively breastfeed for fewer than 10 weeks than were women who had not received the packs (multivariate adjusted odds ratio=1.39; 95% confidence interval=1.05, 1.84). CONCLUSIONS: Commercial hospital discharge packs are one of several factors that influence breastfeeding duration and exclusivity. The distribution of these packs to new mothers at hospitals is part of a longstanding marketing campaign by infant formula manufacturers and implies hospital and staff endorsement of infant formula. Commercial hospital discharge pack distribution should be reconsidered in light of its negative impact on exclusive breastfeeding.

Unintended childbearing and knowledge of emergency contraception in a population-based survey of postpartum women.

OBJECTIVES: We examined the relationship between unintended childbearing and knowledge of emergency contraception. METHODS: The Oregon Pregnancy Risk Assessment Monitoring System (PRAMS) is a population-based survey of postpartum women. We analyzed data from the 2001 PRAMS survey using logistic regression to assess the relationship between unintended childbearing and emergency contraception while controlling for maternal characteristics such as age, race/ethnicity, education, marital status, family income, and insurance coverage before pregnancy. RESULTS: In 2001, 1,795 women completed the PRAMS survey (78.1% weighted response proportion). Of the women who completed the survey, 38.2% reported that their birth was unintended and 25.3% reported that they did not know about emergency contraception before pregnancy. Unintended childbearing was associated with a lack of knowledge of emergency contraception (OR 1.43, 95% CI 1.00, 2.05) after controlling for marital status and age. CONCLUSIONS: Women in Oregon who were not aware of emergency contraception before pregnancy were more likely to have had an unintended birth when their marital status and age were taken into account. Unintended birth was more likely among women who were young, unmarried, lower income, and uninsured. Given that emergency contraception is now available over-the-counter in the US to women who are 18 years of age or older, age- and culturally-appropriate public health messages should be developed to expand women's awareness of, dispel myths around, and encourage appropriate use of emergency contraception as a tool to help prevent unintended pregnancy and birth.

Reduced Plasmodium vivax erythrocyte infection in PNG Duffy-negative heterozygotes.

BACKGROUND: Erythrocyte Duffy blood group negativity reaches fixation in African populations where Plasmodium vivax (Pv) is uncommon. While it is known that Duffy-negative individuals are highly resistant to Pv erythrocyte infection, little is known regarding Pv susceptibility among heterozygous carriers of a Duffy-negative allele (+/-). Our limited knowledge of the selective advantages or disadvantages associated with this genotype constrains our understanding of the effect that interventions against Pv may have on the health of people living in malaria-endemic regions. METHODS AND FINDINGS: We conducted cross-sectional malaria prevalence surveys in Papua New Guinea (PNG), where we have previously identified a new Duffy-negative allele among individuals living in a region endemic for all four human malaria parasite species. We evaluated infection status by conventional blood smear light microscopy and semi-quantitative PCR-based strategies. Analysis of a longitudinal cohort constructed from our surveys showed that Duffy heterozygous (+/-) individuals were protected from Pv erythrocyte infection compared to those homozygous for wild-type alleles (+/+) (log-rank tests: LM, p = 0.049; PCR, p = 0.065). Evaluation of Pv parasitemia, determined by semi-quantitative PCR-based methods, was significantly lower in Duffy +/- vs. +/+ individuals (Mann-Whitney U: p = 0.023). Overall, we observed no association between susceptibility to P. falciparum erythrocyte infection and Duffy genotype. CONCLUSIONS: Our findings provide the first evidence that Duffy-negative heterozygosity reduces erythrocyte susceptibility to Pv infection. As this reduction was not associated with greater susceptibility to Pf malaria, our in vivo observations provide evidence that Pv-targeted control measures can be developed safely.

Changing patterns of Plasmodium blood-stage infections in the Wosera region of Papua New Guinea monitored by light microscopy and high throughput PCR diagnosis.

In Papua New Guinea (PNG), complex patterns of malaria commonly include single and mixed infections of Plasmodium falciparum, P. vivax, P. malariae, and P. ovale. Here, we assess recent epidemiologic characteristics of Plasmodium blood-stage infections in the Wosera region through four cross-sectional surveys (August 2001 to June 2003). Whereas previous studies performed here have relied on blood smear/light microscopy (LM) for diagnosing Plasmodium species infections, we introduce a newly developed, post-polymerase chain reaction (PCR), semi-quantitative, ligase detection reaction-fluorescent microsphere assay (LDR-FMA). A direct comparison of the two methods for > 1,100 samples showed that diagnosis was concordant for > 80% of the analyses performed for P. falciparum (PF), P. vivax (PV), and P. malariae (PM). Greater sensitivity of the LDR-FMA accounted for 75% of the discordance between diagnoses. Based on LM, the prevalence of blood-stage PF, PV, and PM infections was found to be markedly reduced compared with an early 1990s survey. In addition, there were significant shifts in age distribution of infections, with PV becoming the most common parasite in children < 4 years of age. Consistent with previous studies, prevalence of all Plasmodium species infections increased significantly in samples analyzed by the PCR-based LDR-FMA. This increase was most pronounced for PM, PO, and mixed infections and in adolescent (10-19 years) and adult age groups, suggesting that LM may lead to under-reported prevalence of less common Plasmodium species, infection complexity, and a skewed distribution of infections towards younger age groups. This study shows that the application of LDR-FMA diagnosis in large epidemiologic studies or malaria control interventions is feasible and may contribute novel insights regarding the epidemiology of malaria.

Diagnosing infection levels of four human malaria parasite species by a polymerase chain reaction/ligase detection reaction fluorescent microsphere-based assay.

Improving strategies for diagnosing infection by the four human Plasmodium species parasites is important as field-based epidemiologic and clinical studies focused on malaria become more ambitious. Expectations for malaria diagnostic assays include rapid processing with minimal expertise, very high specificity and sensitivity, and quantitative evaluation of parasitemia to be delivered at a very low cost. Toward fulfilling many of these expectations, we have developed a post-polymerase chain reaction (PCR)/ligase detection reaction-fluorescent microsphere assay (LDR-FMA). This assay, which uses Luminex FlexMAP microspheres, provides simultaneous, semi-quantitative detection of infection by all four human malaria parasite species at a sensitivity and specificity equal to other PCR-based assays. In blinded studies using P. falciparum-infected blood from in vitro cultures, we identified infected and uninfected samples with 100% concordance. Additionally, in analyses of P. falciparum in vitro cultures and P. vivax-infected monkeys, comparisons between parasitemia and LDR-FMA signal intensity showed very strong positive correlations (r > 0.95). Application of this multiplex Plasmodium species LDR-FMA diagnostic assay will increase the speed, accuracy, and reliability of diagnosing human Plasmodium species infections in epidemiologic studies of complex malaria-endemic settings.

Why do we need to know more about mixed Plasmodium species infections in humans?

Four Plasmodium species cause malaria in humans. Most malaria-endemic regions feature mixed infections involving two or more of these species. Factors contributing to heterogeneous parasite species and disease distribution include differences in genetic polymorphisms underlying parasite drug resistance and host susceptibility, mosquito vector ecology and transmission seasonality. It is suggested that unknown factors limit mixed Plasmodium species infections, and that mixed-species infections protect against severe Plasmodium falciparum malaria. Careful examination of methods used to detect these parasites and interpretation of individual- and population-based data are necessary to understand the influence of mixed Plasmodium species infections on malarial disease. This should ensure that deployment of future antimalarial vaccines and drugs will be conducted in a safe and timely manner.

Development of a multiplex PCR-ligase detection reaction assay for diagnosis of infection by the four parasite species causing malaria in humans.

The diagnosis of infections caused by Plasmodium species is critical for understanding the nature of malarial disease, treatment efficacy, malaria control, and public health. The demands of field-based epidemiological studies of malaria will require faster and more sensitive diagnostic methods as new antimalarial drugs and vaccines are explored. We have developed a multiplex PCR-ligase detection reaction (LDR) assay that allows the simultaneous diagnosis of infection by all four parasite species causing malaria in humans. This assay exhibits sensitivity and specificity equal to those of other PCR-based assays, identifying all four human malaria parasite species at levels of parasitemias equal to 1 parasitized erythrocyte/microl of blood. The multiplex PCR-LDR assay goes beyond other PCR-based assays by reducing technical procedures and by detecting intraindividual differences in species-specific levels of parasitemia. Application of the multiplex PCR-LDR assay will provide the sensitivity and specificity expected of PCR-based diagnostic assays and will contribute new insight regarding relationships between the human malaria parasite species and the human host in future epidemiological studies.