Enabling countries to manage outbreaks: statistical, operational, and contextual analysis of the early warning and response system (EWARS-csd) for dengue outbreaks.

Introduction: Dengue is currently the fastest-spreading mosquito-borne viral illness in the world, with over half of the world's population living in areas at risk of dengue. As dengue continues to spread and become more of a health burden, it is essential to have tools that can predict when and where outbreaks might occur to better prepare vector control operations and communities' responses. One such predictive tool, the Early Warning and Response System for climate-sensitive diseases (EWARS-csd), primarily uses climatic data to alert health systems of outbreaks weeks before they occur. EWARS-csd uses the robust Distribution Lag Non-linear Model in combination with the INLA Bayesian regression framework to predict outbreaks, utilizing historical data. This study seeks to validate the tool's performance in two states of Colombia, evaluating how well the tool performed in 11 municipalities of varying dengue endemicity levels. Methods: The validation study used retrospective data with alarm indicators (mean temperature and rain sum) and an outbreak indicator (weekly hospitalizations) from 11 municipalities spanning two states in Colombia from 2015 to 2020. Calibrations of different variables were performed to find the optimal sensitivity and positive predictive value for each municipality. Results: The study demonstrated that the tool produced overall reliable early outbreak alarms. The median of the most optimal calibration for each municipality was very high: sensitivity (97%), specificity (94%), positive predictive value (75%), and negative predictive value (99%; 95% CI). Discussion: The tool worked well across all population sizes and all endemicity levels but had slightly poorer results in the highly endemic municipality at predicting non-outbreak weeks. Migration and/or socioeconomic status are factors that might impact predictive performance and should be further evaluated. Overall EWARS-csd performed very well, providing evidence that it should continue to be implemented in Colombia and other countries for outbreak prediction.

Epidemiological, Serological, and Entomological Investigation of New Visceral Leishmaniasis Foci in Nepal.

The aim of this study was to explore epidemiological, serological, entomological, and social aspects of visceral leishmaniasis (VL) in new foci in Nepal. The study was conducted in 11 villages of five districts that had been previously free of VL but that reported new cases between 2019 and 2021. We screened 1,288 inhabitants using rK39 tests and investigated the epidemiological and clinical characteristics of 12 recent VL cases. A total of 182 community members were interviewed about knowledge, attitude, and practices regarding VL. They then underwent an awareness training; 40 of them had a second interview at 6 months to assess the training impact. Vector surveys were conducted in six houses per village to assess sandfly density and infection rates. The prevalence of VL infection was 0.5% and 3.2% among screened populations in Dolpa and Kavre districts, respectively, while the other districts had no rK39-positive cases. No association between travel history and VL infection was found. Phlebotomus argentipes sandflies were collected in three districts at high altitudes (from 1,084 to 4,450 m). None of the sandflies captured had Leishmania donovani DNA. People in new foci were not aware of VL symptoms, vectors, or preventive measures. The training significantly improved their knowledge and practice in seeking medical care in case of illness. The epidemiological, serological, and entomological investigations suggest indigenous focal transmission of VL. An integrated package of strategic interventions should be implemented by the national VL elimination program in districts with new VL foci.

Assessment of the impact of implementation research on the Visceral Leishmaniasis (VL) elimination efforts in Nepal.

Nepal, Bangladesh, and India signed a Memorandum of Understanding (MoU) in 2005 to eliminate visceral leishmaniasis (VL) as a public health problem from the Indian subcontinent by 2015. By 2021, the number of reported VL cases in these countries had declined by over 95% compared to 2007. This dramatic success was achieved through an elimination programme that implemented early case detection and effective treatment, vector control, disease surveillance, community participation, and operational research that underpinned these strategies. The experience offered an opportunity to assess the contribution of implementation research (IR) to VL elimination in Nepal. Desk review and a stakeholder workshop was conducted to analyse the relationship between key research outputs, major strategic decisions in the national VL elimination programme, and annual number of reported new cases over time between 2005 and 2023. The results indicated that the key decisions across the strategic elements, throughout the course of the elimination programme (such as on the most appropriate tools for diganostics and treatment, and on best strategies for case finding and vector management), were IR informed. IR itself responded dynamically to changes that resulted from interventions, addressing new questions that emerged from the field. Close collaboration between researchers, programme managers, and implementers in priority setting, design, conduct, and review of studies facilitated uptake of evidence into policy and programmatic activities. VL case numbers in Nepal are now reduced by 90% compared to 2005. Although direct attribution of disease decline to research outputs is difficult to establish, the Nepal experience demonstrates that IR can be a critical enabler for disease elimination. The lessons can potentially inform IR strategies in other countries with diseases targeted for elimination.

Follow-up assessment of visceral leishmaniasis treated patients and the impact of COVID-19 on control services in Nepal.

BACKGROUND: Follow-up assessment of visceral leishmaniasis (VL) treated cases is important to monitor the long term effectiveness of treatment regimens. The main objective of this study was to identify the gaps and challenges in the follow-up of treated VL cases, to monitor treatment outcome and to assess the impact of COVID-19 on VL elimination services and activities. METHODS: Clinicians treating VL patients, district focal persons for VL, and patients treated for VL in seven high endemic districts in Nepal during 2019-2022 were interviewed to collect data on challenges in the follow-up of VL treated patients as per national strategy. RESULTS: Follow up status was poor in two districts with the largest number of reported cases. The majority of cases were children under 10 years of age (44.2%). Among 104 VL treated cases interviewed, 60.6% mentioned that clinicians had called them for follow-up but only 37.5% had complied. Among 112 VL treated cases followed up, 8 (7.14%) had relapse and 2 (1.8%) had PKDL. Among 66 cases who had VL during the COVID-19 lock down period, 32 (48.5%) were diagnosed within 1 week; however, 10 (15.1%) were diagnosed only after 4 weeks or more. During the COVID-19 pandemic, there was no active search for VL because of budget constraints and lack of diagnostic tests, and no insecticide spraying was done. CONCLUSION: Relapses and PKDL are challenges for VL elimination and a matter of concern. Successful implementation of the national strategy for follow up of treated VL cases requires addressing elements related to patients (awareness, transport, communication) clinicians (compliance) and organization of service delivery (local health worker training and deployment). COVID-19 did not have much impact on VL diagnosis and treatment; however, public health programmes including active case detection and insecticide spraying for vector control were severely reduced.

Epidemiological, serological, and entomological aspects of visceral leishmaniasis (VL) in suspected new VL foci in Bangladesh.

The study aimed to explore epidemiological, serological, and entomological aspects of visceral leishmaniasis (VL) in suspected new VL foci and assess the knowledge, attitude, and practices of the community living in the alleged new VL foci. The study investigated new visceral leishmaniasis (VL) cases reported between 2019 and 2020 in four sub-districts (Dharmapasha, Hakimpur, Islampur and Savar) where we tested 560 members using the rK39 rapid test and conducted vector collections in six neighbouring houses of the index cases to assess sandfly density and distribution, examined sandflies' infection, and determined the spatial relationship with VL infection. Furthermore, we highlighted the importance of early detection, and community awareness in controlling the spread of the disease. The study screened 1078 people from 231 households in the four sub-districts for fever, history of visceral leishmaniasis (VL), and PKDL-like skin lesions. Among sub-districts, positivity rate for rK39 rapid test was highest (3.5 %) in Savar. Sandflies were present across all areas except in Dharmapasha, but all 21 collected female P. argentipes sandflies were negative for Leishmania parasite DNA. We found one person from Islampur with a history of VL, and one from Islampur and another one from Savar had PKDL. After the awareness intervention, more people became familiar with VL infection (91.2 %), and their knowledge concerning sandflies being the vector of the disease and the risk of having VL increased significantly (30.1 %). The study found no active case in the suspected new foci, but some asymptomatic individuals were present. As sandfly vectors exist in these areas, the National Kala-azar Elimination Programme (NKEP) should consider these areas as kala-azar endemic and initiate control activities as per national guidelines.

Long-Term Efficacy of Insecticidal Wall Painting for Controlling Visceral Leishmaniasis Vectors in Bangladesh.

The success of the visceral leishmaniasis (VL) elimination program largely depends on cost-effective vector control measures. Our goal was to investigate the longevity of the efficacy of insecticidal wall painting (IWP), a new vector control tool, compared with a routine indoor residual spraying (IRS) program for reducing the VL vector density in Bangladesh. This study is the extension of our recent IWP study for VL vector management in Bangladesh, which was undertaken in seven highly VL endemic villages of the Mymensingh district with a 12-month follow-up. In this 24-months follow-up study, we collected sand flies additionally at 15, 18, 21, and 24 months since the interventions from the IWP and control (where the program did routine IRS) clusters to examine the longevity of the efficacy of IWP on sand fly density reduction and mortality. The difference-in-differences regression models were used to estimate the effect of IWP on sand fly reduction against Program IRS. The IWP showed excellent performance in reducing sand fly density and increasing sand fly mortality compared with Program IRS. The effect of IWP for controlling sand flies was statistically significant for up to at least 24 months. The mean female Phlebotomus argentipes density reduction ranged from -56% to -83%, and the P. argentipes sand fly mortality ranged from 81% to 99.5% during the 24-month follow-up period. Considering the duration of the efficacy of IWP for controlling VL vectors, Bangladesh National Kala-azar Elimination Program may consider IWP as the best alternative to IRS for the subsequent phases of the program.

Early warning and response system for dengue outbreaks: Moving from research to operational implementation in Mexico.

Dengue disease epidemics have increased in time and space due to climatic and non-climatic factors such as urbanization. In the absence of an effective vaccine, preventing dengue outbreak relies on vector control activities. Employing computerized tools to predict outbreaks and respond in advance has great potential for improving dengue disease control. Evidence of integrating or implementing such applications into control programs and their impact are scarce, and endemic countries demand for experience sharing and know-how transfer. Mexico has extensive experience of pre-validated EWARS (Early Warning And Response System), a tool that was developed in 2012 as part of a collaboration with the Special Program for Research and Training in Tropical Diseases Unit (TDR) at the World Health Organization and used at national level. The advancement of EWARS since 2014 and its stepwise integration into the national surveillance system has increased the appreciation of the need for integrated surveillance (including disease, vector and climate surveillance), and for linking inter-institutional and trans-sectoral information for holistic epidemiological intelligence. The integration of the EWARS software into the national surveillance platform in Mexico was a remarkable milestone and a successful experience. This manuscript describes the implementation process of EWARS in Mexico, which started in 2012 and further demonstrates benefits, threats, and opportunities of integrating EWARS into existing national surveillance programs.

Assessment of treatment outcomes of visceral leishmaniasis (VL) treated cases and impact of COVID-19 on VL management and control services in Bangladesh.

BACKGROUND: COVID-19 has largely impacted the management of Visceral leishmaniasis (VL), like several other Neglected Tropical Diseases. The impact was particularly evident in Lower and Middle-Income countries where the already inadequate healthcare resources were diverted to managing the COVID-19 pandemic. Bangladesh achieved the elimination target for VL in 2016. To sustain this success, early diagnosis and treatment, effective vector control, and periodic surveillance are paramount. However, the specific control measures for VL in Bangladesh that were hampered during COVID-19 and their extent are unknown. METHODS: This study aimed at identifying the gaps and challenges in the follow-up of treated VL patients by interviewing both the treated VL cases and their health service providers. We followed VL cases treated between 2019 and 2020 in five VL endemic subdistricts (upazilas) both retrospectively and prospectively to monitor clinical improvement, relapse, or other consequences. Moreover, interviews were conducted with the health service providers to assess the impact of COVID-19 on VL case detection, treatment, reporting, vector control operations, and logistic supply chain management. RESULTS: There was no added delay for VL diagnosis; however, VL treatment initiation and reporting time increased almost two-fold due to COVID-19. Indoor Residual Spraying activity was significantly hampered due to a shortage of insecticides. Out of 44 enrolled and treated VL patients, two relapsed (4.5 %), two developed Para Kala-Azar Dermal Leishmaniasis (4.5 %), and three (6.8 %) Post Kala-Azar Dermal Leishmaniasis (PKDL). The health service providers highlighted patients` unwillingness to visit the hospital, financial constraints, and distance from the hospitals as the main reasons for missed follow-up visits (20.5 %). Building good communication in the community, awareness schemes, and incentive-based approaches were suggested as possible solutions to mitigate these problems. CONCLUSION: Long-term follow-up is required for the early detection and management of VL relapse and PKDL cases. Effective vector control measures, capacity development, and identification of new VL hotspots are pivotal in the VL endemic regions to sustain the elimination goal.

Risk of dengue, Zika, and chikungunya transmission in the metropolitan area of Cucuta, Colombia: cross-sectional analysis, baseline for a cluster-randomised controlled trial of a novel vector tool for water containers.

BACKGROUND: Arbovirus diseases such as dengue, Zika, and chikungunya are a public health threat in tropical and subtropical areas. In the absence of a vaccine or specific treatment, vector management (in this case the control of the primary vector Aedes aegypti) is the best practice to prevent the three diseases. A good understanding of vector behaviour, ecology, human mobility and water use can help design effective vector control programmes. This study collected baseline information on these factors for identifying the arbovirus transmission risk and assessed the requirements for a large intervention trial in Colombia. METHODS: Baseline surveys were conducted in 5,997 households, randomly selected from 24 clusters (neighbourhoods with on average 2000 houses and 250 households inspected) in the metropolitan area of Cucuta, Colombia. The study established population characteristics including water management and mobility as well as larval-pupal indices which were estimated and compared in all clusters. Additionally, the study estimated disease incidence from two sources: self-reported dengue cases in the household survey and cases notified by the national surveillance system. RESULTS: In all 24 study clusters similar social and demographic characteristics were found but the entomological indicators and estimated disease incidence rates varied. The entomological indicators showed a high vector infestation: House Index = 25.1%, Container Index = 12.3% and Breteau Index = 29.6. Pupae per person Index (PPI) as an indicator of the transmission risk showed a large range from 0.22 to 2.04 indicating a high transmission risk in most clusters. The concrete ground tanks for laundry -mostly outdoors and uncovered- were the containers with the highest production of Ae. aegypti as 86.3% of all 17,613 pupae were identified in these containers. Also, the annual incidence of dengue was high: 841.6 self-reported cases per 100,000 inhabitants and the dengue incidence notified by the National surveillance system was 1,013.4 cases per 100,000 in 2019. Only 2.2% of the households used container water for drinking. 40.3% of the study population travelled during the day (when Aedes mosquitoes bite) outside their clusters. CONCLUSIONS: The production of Ae. aegypti mosquitoes occurred almost exclusively in concrete ground tanks for laundry (lavadero), the primary intervention target. The baseline study provides necessary evidence for the design and implementation of a cluster randomized intervention trial in Colombia.

Dengue and zika seropositivity, burden, endemicity, and cocirculation antibodies in Nigeria.

INTRODUCTION: Mosquito-borne infections are of global health concern because of their rapid spread and upsurge, which creates a risk for coinfections. DENV and ZIKV are transmitted by Aedes aegypti and A. albopictus and are prevalent in Nigeria and neighbouring countries. However, their seroprevalence, burden, hidden endemicity and possible cocirculation are poorly understood in Nigeria. METHODS: We conducted a cross-sectional study of 871 participants from three regions of Nigeria. All serum samples were analysed using malaria RDT and the immunoblot molecular diagnostic assay recomLine Tropical Fever for the presence of arboviral antibody serological marker IgG (Mikrogen Diagnostik, Neuried, Germany) with DENV and ZIKV Nonstructural protein 1 (NS 1), DENV and ZIKV Equad (variant of the envelope protein with designated mutations to increase specificity), according to the manufacturer's instructions. RESULTS: The overall IgG antibody seropositivity against DENV-flavivirus was 44.7% (389/871); 95% CI (41.41-47.99), while ZIKV-flavivirus was 19.2% (167/871); 95% CI (0.16-0.21), and DENV-ZIKV-flavivirus cocirculation antibody seropositivity was 6.2%5 (54/871); 95% CI (0.6-0.7) in the three study regions of Nigeria. The study cohort presented similar clinical signs and symptoms of flaviviruses (DENV and ZIKV) in all three study regions. CONCLUSION: This study highlighted an unexpectedly high antibody seropositivity, burden, hidden endemicity, and regional spread of mono- and co-circulating flaviviruses (DENV and ZIKV) in Nigeria.Key messagesDengue flavivirus sero-cross-reactivity drives antibody-dependent enhancement of ZIKV infection.Both viruses share common hosts (humans) and vectors (primarily Aedes aegypti), and are thus influenced by similar biological, ecological, and economic factors, resulting in epidemiological synergy.Additionally, the actual burden in epidemic and interepidemic periods is grossly or chronically unknown and underreported. Despite this trend and the potential public health threat, there are no reliable data, and little is known about these arboviral co-circulation infections.

Antibody seropositivity and endemicity of chikungunya and Zika viruses in Nigeria.

Mosquito-borne infections are of global health concern because of their rapid spread and upsurge, which creates a risk for coinfections. chikungunya virus (CHIKV), an arbovirus disease transmitted by Aedes aegypti or A. albopictus, and malaria, a parasitic disease transmitted by Anopheles gambiae, are prevalent in Nigeria and neighbouring countries, but their burden and possible coinfections are poorly understood. In this study, we investigated the antibody seropositivity and endemicity of chikungunya and Zika viruses (ZIKV) in three regions of Nigeria. A cross-sectional sero-survey was conducted on 871 participants. Samples were collected from outpatients by simple random sampling. Analyses of the samples were performed using recomLine Tropical Fever for the presence of antibody serological marker IgG immunoblot with CHIKV VLP (virus like particle), ZIKV NS1 and ZIKV Equad according to manufacturers' instructions and malaria RDT for malaria parasite. There was a significantly higher antibody seropositivity against CHIKV in the central region than in the northern and southern regions (69.5%, 291/419), while ZIKV-seropositivity (22.4%, 34/152) and CHIKV-ZIKV co-circulating antibody seropositivity (17.8%, 27/152) were notably higher in the southern region than in the central and northern regions. This investigation revealed an unexpectedly high antibody seropositivity and concealed endemicity of CHIKV and ZIKV in three Nigerian regions. The seropositivity of detectable antibodies differed among the three geographical locations. Supplementary Information: The online version contains supplementary material available at 10.1186/s44149-023-00070-2.

Zika, Flavivirus and Malaria Antibody Cocirculation in Nigeria.

Introduction. Arboviruses and malaria pose a growing threat to public health, affecting not only the general population but also immunocompromised individuals and pregnant women. Individuals in vulnerable groups are at a higher risk of severe complications from the co-circulation and transmission of ZIKV, malaria, and FLAVI fever. In sub-Saharan countries, such as Nigeria, these mosquito-borne infections have clinical presentations that overlap with other diseases (dengue, West Nile virus, and Japanese encephalitis, chikungunya, and O'nyong o'nyong virus), making them a diagnostic challenge for clinicians in regions where they co-circulate. Vertical transmission can have a devastating impact on maternal health and fetal outcomes, including an increased risk of fetal loss and premature birth. Despite the global recognition of the burden of malaria and arboviruses, particularly ZIKV and other flaviviruses, there is limited data on their prevalence in Nigeria. In urban settings, where these diseases are endemic and share common biological, ecological, and economic factors, they may impact treatment outcomes and lead to epidemiological synergy. Hence, it is imperative to conduct sero-epidemiological and clinical studies to better understand the disease burden and hidden endemicity, thereby enabling improved prevention and clinical management. Method. Serum samples collected from outpatients between December 2020 and November 2021 in three regions of Nigeria were tested for the presence of IgG antibody seropositivity against ZIKV and FLAVI using immunoblot serological assay. Results. The overall cohort co-circulation antibody seropositivity of ZIKV, FLAVI and malaria was 24.0% (209/871). A total of 19.2% (167/871) of the study participants had ZIKV-seropositive antibodies and 6.2% (54/871) were FLAVI-seropositive, while 40.0% (348/871) of the subjects had malaria parasite antigens. Regional analysis revealed that participants from the southern region had the highest antibody seropositivity against ZIKV (21.7% (33/152)) and FLAVI (8.6% (13/152)), whereas those from the central region had a higher malaria parasite antigen (68.5% (287/419)). Conclusions. This study represents the largest comparative cross-sectional descriptive sero-epidemiological investigation of ZIKV-FLAVI and malaria cocirculation in Nigeria. The findings of this study revealed increased antibody seropositivity, hidden endemicity, and the burden of ZIKV, FLAVI, and malaria co-circulating in Nigeria.

Prevalence of post kala-azar dermal leishmaniasis (PKDL) and treatment seeking behavior of PKDL patients in Nepal.

BACKGROUND: In Nepal, the burden of post kala-azar dermal leishmaniasis (PKDL) is not known since there is no active case detection of PKDL by the national programme. PKDL patients could pose a challenge to sustain visceral leishmaniasis (VL) elimination. The objective of this study was to determine the prevalence of PKDL and assess PKDL patients' knowledge on VL and PKDL, and stigma associated with PKDL. METHODOLOGY/PRINCIPAL FINDINGS: Household surveys were conducted in 98 VL endemic villages of five districts that reported the highest number of VL cases within 2018-2021. A total of 6,821 households with 40373 individuals were screened for PKDL. Cases with skin lesions were referred to hospitals and examined by dermatologists. Suspected PKDL cases were tested with rK39 and smear microscopy from skin lesions. An integrated diagnostic approach was implemented in two hospitals with a focus on management of leprosy cases where cases with non-leprosy skin lesions were tested for PKDL with rK39. Confirmed PKDL patients were interviewed to assess knowledge and stigma associated with PKDL, using explanatory model interview catalogue (EMIC) with maximum score of 36. Among 147 cases with skin lesions in the survey, 9 (6.12%) were confirmed as PKDL by dermatologists at the hospital. The prevalence of PKDL was 2.23 per 10,000 population. Among these 9 PKDL cases, 5 had a past history of VL and 4 did not. PKDL cases without a past history of VL were detected among the "new foci", Surkhet but none in Palpa. None of the cases negative for leprosy were positive for PKDL. There was very limited knowledge of PKDL and VL among PKDL cases. PKDL patients suffered to some degree from social and psychological stigma (mean ± s.d. score = 17.89 ± 12.84). CONCLUSIONS/SIGNIFICANCE: Strengthening the programme in PKDL case detection and management would probably contribute to sustenance of VL elimination. Awareness raising activities to promote knowledge and reduce social stigma should be conducted in VL endemic areas.

Applicability of the Mexican ovitrap system for Aedes vector surveillance in Colombia.

Ovitraps can detect Aedes vectors at an early stage and can serve as an alarm indicator for outbreak prediction. This study aimed to summarize the available literature about the ovitrap system and to determine its feasibility, required resources and costs when installing and maintaining this vector surveillance system in the municipality of Los Patios, Colombia. A scoping review to assess the role of ovitraps as a tool for Aedes vector surveillance was conducted. The subsequent fieldwork consisted of mapping the municipality, manufacturing, and installing 40 ovitraps in 10 blocks, revising them weekly for 4 weeks by two half-time employed vector control technicians, and carrying out a cost analysis. A total of 38 studies were included in this review showing that ovitraps had a better performance than other entomological surveillance methods and a positive correlation with other entomological and disease variables. From the field results over 4 weeks, a high proportion of positive ovitraps (80%, 90%, 75%, 97.5%) and positive blocks (100%) as well as a good acceptance by house owners (76.9%), were identified. Operational indicators such as average installation time of the ovitraps (10h15 m), weekly reading and reinstallation (on average 7h27 m) and the cost of the intervention (COL$1,142,304.47/US$297) were calculated. Literature shows that ovitraps are sensitive to detect the presence of Aedes mosquitoes, providing data efficiently and timely for outbreak prediction. The field testing showed it is an affordable and feasible method in the context of a Colombian municipality and similar endemic areas.

Visceral leishmaniasis in new foci areas of Nepal: Sources and extent of infection.

Background & objectives: The successful elimination program of visceral leishmaniasis (VL) in Nepal decreased the incidence to less than 1 per 10,000 population leading to the consolidation phase. However, new VL cases have been recorded from new districts, threatening the elimination goal. This study monitors the geographical spread of VL and identifies potential risk factors. Methods: VL data of 2017-2020 were obtained from the Epidemiology and Disease Control Division (EDCD) of Nepal and mapped. Telephonic interviews with 13 VL patients were conducted. Results: The incidence maps indicate that VL is spreading to new areas. The target incidence exceeded four times in hilly and twice in mountainous districts. VL cases occurred in 64 of 77 districts in all three regions (mountainous, hilly and Terai). Interviews showed a correlation between travel history (private, commercial and for studies) and the spread of VL cases to new foci. Interpretation & conclusion: One major challenge of VL elimination in the maintenance phase is the spread of infection through travelers to new foci areas, which needs to be under continuous surveillance accompanied by vector control activities. This should be confirmed by a large-scale analytical study.

The Seroprevalence and Hidden Burden of Chikungunya Endemicity and Malaria Mono- and Coinfection in Nigeria.

Background: Mosquito-borne infections are of global health concern because of their rapid spread and upsurge, which creates a risk for coinfections. Chikungunya, an arbovirus disease transmitted by Aedes aegypti or A. albopictus, and malaria, a parasitic disease transmitted by Anopheles gambiae, are prevalent in Nigeria and neighbouring countries, but their burden and possible coinfections are poorly understood. In this study, we investigated the seroprevalence, hidden burden and endemicity of chikungunya and malaria in three regions in Nigeria. Methods: A cross-sectional sero-survey was conducted on 871 participants in three regions of Nigeria. The samples were collected from outpatients employing simple random sampling. All serum sample analyses were performed using CHIKV virus-like particle recomLine Tropical Fever for the presence of arboviral antibody serological marker IgG immunoblot for chikungunya and malaria RDT (Rapid Diagnostic Test) for malaria parasites. Results: The seroprevalences of chikungunya and malaria mono-infection were 64.9% and 27.7%, respectively, while the coinfection seroprevalence was 71.9%. The central (69.5%) and northern (67.0%) regions showed more significant seroprevalences than the southern region (48.0%). The seroprevalence and the hidden burden of chikungunya and malaria infections varied across the three geographical regions. Conclusions: This study highlighted an unexpectedly high seroprevalence and hidden endemicity of chikungunya and a less surprising high malaria endemicity in three regions of Nigeria.

Response to Visceral Leishmaniasis Cases through Active Case Detection and Vector Control in Low-Endemic Hilly Districts of Nepal.

The visceral leishmaniasis (VL) elimination program in Nepal has largely completed the attack phase and is moving toward consolidation and maintenance phases. New VL foci are, however, appearing in Nepal, and therefore new innovative community-centered strategies need to be developed and tested. We conducted early case detection by an index case-based approach and assessed the feasibility, efficacy, and cost of an intervention for sandfly control through indoor residual spraying (IRS) or insecticidal wall painting (IWP) in new and low-endemic districts Palpa and Surkhet. IRS was performed in 236 households and IWP in 178 households. We screened 1,239 and 596 persons in Palpa and Surkhet, respectively, resulting in the detection of one VL case in Palpa. Both IWP and IRS were well accepted, and the percentage reductions in sandfly density after 1, 9, and 12 months of intervention were 90%, 81%, and 75%, respectively, for IWP and 81%, 59%, and 63% respectively for IRS. The cost per household protected per year was USD 10.3 for IRS and 32.8 for IWP, although over a 2-year period, IWP was more cost-effective than IRS. Active case detection combined with sandfly control through IWP or IRS can support to VL elimination in the consolidation and maintenance phase.

The Early Warning and Response System (EWARS-TDR) for dengue outbreaks: can it also be applied to chikungunya and Zika outbreak warning?

BACKGROUND: In the Americas, endemic countries for Aedes-borne diseases such as dengue, chikungunya, and Zika face great challenges particularly since the recent outbreaks of CHIKV and ZIKV, all transmitted by the same insect vectors Aedes aegypti and Ae. albopictus. The Special Program for Research and Training in Tropical Diseases (TDR-WHO) has developed together with partners an Early Warning and Response System (EWARS) for dengue outbreaks based on a variety of alarm signals with a high sensitivity and positive predictive value (PPV). The question is if this tool can also be used for the prediction of Zika and chikungunya outbreaks. METHODOLOGY: We conducted in nine districts of Mexico and one large city in Colombia a retrospective analysis of epidemiological data (for the outbreak definition) and of climate and entomological data (as potential alarm indicators) produced by the national surveillance systems for dengue, chikungunya and Zika outbreak prediction covering the following outbreak years: for dengue 2012-2016, for Zika 2015-2017, for chikungunya 2014-2016. This period was divided into a "run in period" (to establish the "historical" pattern of the disease) and an "analysis period" (to identify sensitivity and PPV of outbreak prediction). RESULTS: In Mexico, the sensitivity of alarm signals for correctly predicting an outbreak was 100% for dengue, and 97% for Zika (chikungunya data could not be obtained in Mexico); the PPV was 83% for dengue and 100% for Zika. The time period between alarm and start of the outbreak (i.e. the time available for early response activities) was for Zika 4-5 weeks. In Colombia the sensitivity of the outbreak prediction was 92% for dengue, 93% for chikungunya and 100% for Zika; the PPV was 68% for dengue, 92% for chikungunya and 54% for Zika; the prediction distance was for dengue 3-5 weeks, for chikungunya 10-13 weeks and for Zika 6-10 weeks. CONCLUSION: EWARS demonstrated promising capability of timely disease outbreak prediction with an operational design likely to improve the coordination among stakeholders. However, the prediction validity varied substantially across different types of diseases and appeared less optimal in low endemic settings.

Mental health among displaced and non-displaced populations in Valledupar, Colombia: do inequalities continue?

During the long-lasting civil war in Colombia, thousands of people were displaced mainly from rural to urban areas, causing social disruption and prolonged poverty. This study aimed at analyzing the traumatic experience many years ago on the current psycho-emotional status of displaced families as well as the ongoing inequalities regarding displaced and non-displaced communities in one of the most affected areas by the armed conflict. An interview survey was conducted among 211 displaced families and 181 non-displaced families in 2 adjacent compounds in Valledupar, Colombia. The questionnaire used questions from the validated national survey and was revised and applied by staff members of the departmental secretary of health who conducted additional in-depth interviews. The study showed that the living conditions of the displaced community were precarious. The past traumatic events many years ago and the current difficult living conditions are associated with psychological problems being more frequent among the displaced people. The displaced people had experienced more violent acts and subsequently had a larger number of emotional symptoms (fright, headache, nervousness, depression, and sleeplessness). Other stress factors like economic problems, severe disease or death of family members and unemployment prevailed among displaced persons. The non-displaced lived in a more protected environment with less exposure to violence and stress, although belonging to a similarly low socio-economic stratum. It is recommended to take measures for a better protection of the displaced community, improve their access to the job market, offer different leisure activities and facilitate public transport.

Validation of the Early Warning and Response System (EWARS) for dengue outbreaks: Evidence from the national vector control program in Mexico.

BACKGROUND: During 2017, twenty health districts (locations) implemented a dengue outbreak Early Warning and Response System (EWARS) in Mexico, which processes epidemiological, meteorological and entomological alarm indicators to predict dengue outbreaks and triggers early response activities. Out of the 20 priority districts where more than one fifth of all national disease transmission in Mexico occur, eleven districts were purposely selected and analyzed. Nine districts presented outbreak alarms by EWARS but without subsequent outbreaks ("non-outbreak districts") and two presented alarms with subsequent dengue outbreaks ("outbreak districts"). This evaluation study assesses and compares the impact of alarm-informed response activities and the consequences of failing a timely and adequate response across the outbreak groups. METHODS: Five indicators of dengue outbreak response (larval control, entomological studies with water container interventions, focal spraying and indoor residual spraying) were quantitatively analyzed across two groups ("outbreak districts" and "non-outbreak districts"). However, for quality control purposes, only qualitative concluding remarks were derived from the fifth response indicator (fogging). RESULTS: The average coverage of vector control responses was significantly higher in non-outbreak districts and across all four indicators. In the "outbreak districts" the response activities started late and were of much lower intensity compared to "non-outbreak districts". Vector control teams at districts-level demonstrated diverse levels of compliance with local guidelines for 'initial', 'early' and 'late' responses to outbreak alarms, which could potentially explain the different outcomes observed following the outbreak alarms. CONCLUSION: Failing timely and adequate response of alarm signals generated by EWARS showed to negatively impact the disease outbreak control process. On the other hand, districts with adequate and timely response guided by alarm signals demonstrated successful records of outbreak prevention. This study presents important operational scenarios when failing or successding EWARS but warrants investigating the effectiveness and cost-effectiveness of EWARS using a more robust designs.