Dengue severity by serotype in 19 years of pediatric clinical studies in Nicaragua.

Background: Dengue virus, a major global health threat, consists of four serotypes (DENV1-4) that cause a range of clinical manifestations from mild to severe and potentially fatal disease. Methods: This study, based on 19 years of data from the Pediatric Dengue Cohort Study and Pediatric Dengue Hospital-based Study in Managua, Nicaragua, investigates the influence of serotype and immune status on dengue severity. Study participants 6 months to 17 years old were followed during their hospital stay or as ambulatory patients, with dengue cases confirmed by molecular, serological, and/or virological methods. Results: We enrolled a total of 14071 participants, of whom 2954 (21%) were positive for DENV infection. Of 2425 cases with serotype result by RT-PCR, 541 corresponded to DENV1, 996 to DENV2, 718 to DENV3 and 170 to DENV4. Severe disease was more prevalent among secondary DENV2 and DENV4 cases, while similar disease severity was observed in both primary and secondary DENV1 and DENV3 cases. According to the 1997 World Health Organization (WHO) severity classification, both DENV2 and DENV3 had a higher proportion of severe disease compared to other serotypes, whereas DENV3 had the greatest percentage of severity under the WHO-2009 classification. DENV2 was associated with pleural effusion and low platelet count, while DENV3 correlated with both hypotensive and compensated shock. Conclusions: These findings emphasize the critical need for a dengue vaccine with balanced efficacy against all four serotypes, particularly as existing vaccines show variable efficacy by serotype and immune status, posing challenges for comprehensive protection, particularly in dengue-naïve individuals.

Incorporating an intersectional gender approach to improve access to maternal and child health screening services.

BACKGROUND: In the Americas, the Pan American Health Organization (PAHO) has promoted initiatives that aim at the elimination of mother-to-child transmitted diseases for over two decades. Although Guatemala has assumed the commitment to improve access and coverage of reproductive and perinatal services, the goals have not yet been reached. Often, the implementation of these efforts is hampered by complexities rooted in social, cultural, and environmental intersections. The objective of this work is to share our experience applying gender intersectionality as a methodological and analytical tool in a participatory research project that aims to improve access to maternal and child health screening services. The study shows the novel strategy that incorporates intersectionality contributing to evidence on how it can be applied to strengthen public health efforts around the implementation of the EMTCT Plus (Elimination of mother-to-child transmission of HIV, Syphilis, Hepatitis B, and Chagas disease) framework, in the mostly rural municipality of Comapa, in Guatemala. METHODS: We applied a participatory methodology, integrating theoretical and methodological frameworks to have an intersectional understanding of health services delivered by both, midwives, and the public health institution, for the prevention, diagnosis, treatment, and follow-up of HIV, Syphilis, Hepatitis B, and Chagas. The data was collected by conducting interviews, focus groups, workshops, and reviewing laboratory databases, guided by five strategies from a cultural appropriateness framework. RESULTS: The intersectional analysis shed light on the synergies and gaps of the current efforts and protocols implemented by both the midwives and the Ministry of Health. The services offered for the four diseases were often delivered independently from each other, and a comprehensive educational and communication material strategy was absent. However, our findings will be used to inform consistent, locally relevant, and culturally appropriate educational content for the local population, also following the national policy guidelines. CONCLUSIONS: Using intersectionality as a method and as an analytical tool allowed us to understand the (1) interrelation of diverse social, cultural, and environmental determinants which influence the delivery of health services, as well as (2) the dynamics between the traditional and institutional health systems. (3) Community engagement and the participation of different stakeholders in a consultative process have been fundamental for the conceptual and methodological tenets of this research. (4) Finally, giving a more prominent role to midwives can strengthen sustainability and cultural appropriateness, which is complementary to the delivery of institutional health services.

RESUMEN: ANTECEDENTES: La Organización Panamericana de la Salud (OPS) ha impulsado iniciativas que buscan la eliminación de las enfermedades de transmisión materno infantil en las Américas desde hace más de dos décadas. Si bien Guatemala ha asumido el compromiso de mejorar el acceso y la cobertura de los servicios reproductivos y perinatales, las metas aún no se han alcanzado. Muchas veces, la implementación de estos esfuerzos se ve obstaculizada por complejidades arraigadas en intersecciones sociales, culturales y ambientales. Este estudio muestra una estrategia novedosa que incorpora la interseccionalidad como un componente metodológico y analítico. Esto contribuye a evidenciar la manera en que la interseccionalidad y la participación comunitaria pueden ser aplicadas para fortalecer los esfuerzos de salud pública en torno a la implementación de la estrategia ETMI Plus (Eliminación de la transmisión materno infantil del VIH, sífilis, hepatitis B y enfermedad de Chagas), en el municipio de Comapa, en Guatemala, el cual es mayoritariamente rural. MéTODOS: Implementamos una metodología participativa, integrando marcos teóricos y metodológicos para comprender la prestación de servicios de salud, tanto por parte de comadronas como de la institución de salud pública, desde una perspectiva interseccional para la prevención, diagnóstico, tratamiento y seguimiento de VIH, sífilis, hepatitis B y Chagas. Los datos fueron recolectados a través de entrevistas, grupos focales, talleres y tras la revisión de bases de datos de laboratorio, y nos guiamos por cinco estrategias propuestas en un marco para pertinencia cultural. RESULTADOS: El análisis interseccional permitió entender las sinergias y brechas de los esfuerzos y los protocolos que se implementan actualmente, tanto por parte de las comadronas como por el Ministerio de Salud. Encontramos que los servicios que actualmente se prestan para las cuatro enfermedades son en su mayoría independientes entre sí, y no se contaba con una estrategia integral de material educativo y de comunicación. Sin embargo, nuestros resultados se utilizarán como base para una estrategia de comunicación que sea coherente, localmente relevante y culturalmente apropiada para la población local, y también siga las regulaciones de las políticas nacionales. CONCLUSIONES: El uso de la interseccionalidad como método y como herramienta analítica nos permitió comprender (1) la interrelación de diversos determinantes sociales, culturales y ambientales que influyen en la prestación de servicios de salud, así como (2) la dinámica entre los sistemas de salud tradicional e institucional. (3) El compromiso de la comunidad y la participación de las diferentes partes interesadas en un proceso consultivo han sido fundamentales para los principios conceptuales y metodológicos de esta investigación. (4) Por último, otorgar un papel más destacado a las matronas puede reforzar la sostenibilidad y la adecuación cultural, que es complementaria a la prestación de servicios de salud institucionales.

Evaluation of the durability of long-lasting insecticidal nets in Guatemala.

BACKGROUND: Insecticide-treated bed nets (ITNs) are widely used for the prevention and control of malaria. In Guatemala, since 2006, ITNs have been distributed free of charge in the highest risk malaria-endemic areas and constitute one of the primary vector control measures in the country. Despite relying on ITNs for almost 15 years, there is a lack of data to inform the timely replacement of ITNs whose effectiveness becomes diminished by routine use. METHODS: The survivorship, physical integrity, insecticide content and bio-efficacy of ITNs were assessed through cross-sectional surveys conducted at 18, 24 and 32 months after a 2012 distribution of PermaNet® 2.0 in a malaria focus in Guatemala. A working definition of 'LLIN providing adequate protection' was developed based on the combination of the previous parameters and usage of the net. A total of 988 ITNs were analysed (290 at 18 months, 349 at 24 months and 349 at 32 months). RESULTS: The functional survivorship of bed nets decreased over time, from 92% at 18 months, to 81% at 24 months and 69% at 32 months. Independent of the time of the survey, less than 80% of the bed nets that were still present in the household were reported to have been used the night before. The proportion of bed nets categorized as "in good condition" per World Health Organization (WHO) guidelines of the total hole surface area, diminished from 77% to 18 months to 58% at 32 months. The portion of ITNs with deltamethrin concentration less than 10 mg/m2 increased over time. Among the bed nets for which bioassays were conducted, the percentage that met WHO criteria for efficacy dropped from 90% to 18 months to 52% at 32 months. The proportion of long-lasting insecticidal nets (LLINs) providing adequate protection was 38% at 24 months and 21% at 32 months. CONCLUSIONS: At 32 months, only one in five of the LLINs distributed in the campaign provided adequate protection in terms of survivorship, physical integrity, bio-efficacy and usage. Efforts to encourage the community to retain, use, and properly care for the LLINs may improve their impact. Durability assessments should be included in future campaigns.

Diversity of Planthoppers (Hemiptera: Delphacidae) on Maize Crops and Edge Grasses in Mexico.

Delphacid planthoppers (Hemiptera: Delphacidae) are a group of economically important sap-feeding insects that vector plant pathogens and are pests of crops, such as maize, wheat, and rice. This study was conducted to evaluate planthopper diversity, abundance, and the presence of potential vectors on maize crops and associated edge grass habitats. In Jalisco, west-central Mexico, delphacids were sampled using a sweep net in two different habitats (with and without irrigation) during the dry and rainy seasons of 2013 and 2014. A total of 5,621 specimens were collected and nine species were identified: Metadelphax propinqua (Fieber), Delphacodes koebelei Muir and Giffard, Delphacodes arcuata Beamer, Sogatella kolophon (Kirkaldy), Syndelphax fulvidorsum (Metcalf), Chionomus balboae (Muir & Giffard), Toya idonea (Beamer), Syndelphax humilis (Van Duzee), and Tagosodes cubanus (Crawford) (Hemiptera: Delphacidae), all belonging to the tribe Delphacini (Delphacinae). A high diversity of delphacids was found in the edge grasses during the dry season and rainy season. Planthopper abundance was higher in the edge grasses than in the maize fields during the rainy season. The most abundant species was M. propinqua representing 67.5% of the specimens collected. Populations of M. propinqua in edge grasses peaked during the dry season in December and January. Metadelphax propinqua, S. kolophon, and T. cubanus are known to be potential plant pathogen vectors.

Associations between household environmental factors and immature mosquito abundance in Quetzaltenango, Guatemala.

BACKGROUND: Aedes aegypti-borne diseases are becoming major public health problems in tropical and sub-tropical regions. While socioeconomic status has been associated with larval mosquito abundance, the drivers or possible factors mediating this association, such as environmental factors, are yet to be identified. We examined possible associations between proximity to houses and roads and immature mosquito abundance, and assessed whether these factors and mosquito prevention measures mediated any association between household environmental factors and immature mosquito abundance. METHODS: We conducted two cross-sectional household container surveys in February-March and November-December, 2017, in urban and rural areas of Quetzaltenango, Guatemala. We used principal components analysis to identify factors from 12 variables to represent the household environment. One factor which included number of rooms in house, electricity, running water, garbage service, cable, television, telephone, latrine, well, and sewer system, was termed "environmental capital." Environmental capital scores ranged from 0 to 5.5. Risk factors analyzed included environmental capital, and distance from nearest house/structure, paved road, and highway. We used Poisson regression to determine associations between distance to nearest house/structure, roads, and highways, and measures of immature mosquito abundance (total larvae, total pupae, and positive containers). Using cubic spline generalized additive models, we assessed non-linear associations between environmental capital and immature mosquito abundance. We then examined whether fumigation, cleaning containers, and distance from the nearest house, road, and highway mediated the relationship between environmental capital and larvae and pupae abundance. RESULTS: We completed 508 household surveys in February-March, and we revisited 469 households in November-December. Proximity to paved roads and other houses/structures was positively associated with larvae and pupae abundance and mediated the associations between environmental capital and total numbers of larvae/pupae (p ≤ 0.01). Distance to highways was not associated with larval/pupal abundance (p ≥ 0.48). Households with the lowest and highest environmental capital had fewer larvae/pupae than households in the middle range (p < 0.01). CONCLUSIONS: We found evidence that proximity to other houses and paved roads was associated with greater abundance of larvae and pupae. Understanding risk factors such as these can allow for improved targeting of surveillance and vector control measures in areas considered at higher risk for arbovirus transmission.

Towards Chagas disease elimination: Neonatal screening for congenital transmission in rural communities.

Chagas disease is a neglected tropical disease that continues to affect populations living in extreme poverty in Latin America. After successful vector control programs, congenital transmission remains as a challenge to disease elimination. We used the PRECEDE-PROCEED planning model to develop strategies for neonatal screening of congenital Chagas disease in rural communities of Guatemala. These communities have persistent high triatomine infestations and low access to healthcare. We used mixed methods with multiple stakeholders to identify and address maternal-infant health behaviors through semi-structured interviews, participatory group meetings, archival reviews and a cross-sectional survey in high risk communities. From December 2015 to April 2016, we jointly developed a strategy to illustratively advertise newborn screening at the Health Center. The strategy included socioculturally appropriate promotional and educational material, in collaboration with midwives, nurses and nongovernmental organizations. By March 2016, eight of 228 (3.9%) pregnant women had been diagnosed with T. cruzi at the Health Center. Up to this date, no neonatal screening had been performed. By August 2016, seven of eight newborns born to Chagas seropositive women had been parasitologically screened at the Health Center, according to international standards. Thus, we implemented a successful community-based neonatal screening strategy to promote congenital Chagas disease healthcare in a rural setting. The success of the health promotion strategies developed will depend on local access to maternal-infant services, integration with detection of other congenital diseases and reliance on community participation in problem and solution definition.

Optimization of mosquito egg production under mass rearing setting: effects of cage volume, blood meal source and adult population density for the malaria vector, Anopheles arabiensis.

BACKGROUND: Anopheles arabiensis is one of the major malaria vectors that put millions of people in endemic countries at risk. Mass-rearing of this mosquito is crucial for strategies that use sterile insect technique to suppress vector populations. The sterile insect technique (SIT) package for this mosquito species is being developed by the Insect Pest Control Subprogramme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. To improve mass-rearing outcomes for An. arabiensis, the question of whether the egg production by females would be affected by the size of the adult holding cages, the source of the blood meal and the total number of pupae that could be loaded into the cages was addressed and finally the impact of adding additional pupae to the cage daily to maintain adult numbers on egg productivity assessed. METHODS: Mass production cages of two different volumes, two different sources of blood meal (bovine and porcine) and two different population densities (cages originally loaded with either 15,000 or 20,000 pupae) were tested and evaluated on the basis of eggs produced/cage or per female. Males and females pupae with a ratio of 1:1 were added to the cages at day 1 and 2 of pupation. The emerging adults had constant access to 5% sugar solution and blood fed via the Hemotek membrane feeding system. Eggs were collected either twice a week or daily. A generalized linear model was used to identify factors which gave significantly higher egg production. RESULTS: Neither cage volume nor blood meal source affected egg production per cage or per female. However, increasing population density to 20,000 pupae had a negative effect on eggs produced per cage and per female. Although high density negatively impacted egg production, adding 1000 daily additional pupae compensating for daily mortality resulted in a substantial increase in egg production. Moreover, in all tests the first and the third egg batches collected were significantly higher than others eggs batches. With the equipment and protocols described here and routinely used at the Insect Pest Control Laboratory (IPCL), it was possible to produce up to 120,000 eggs/cage/day. CONCLUSION: These results demonstrated that 15,000 is the optimal number of pupae to be loaded into the Anopheles Mass production cages. Under this condition, an average of 40 eggs per female was obtained for five gonotrophic cycles. However, an improvement in egg production can be achieved by daily addition, to the original 15,000 pupae, of one thousand pupae a day. Interestingly, feeding females with bovine or porcine blood using both large and small versions of the mass production cage did not affect egg productivity.