RESUMO
BACKGROUND: Thailand aimed to eliminate malaria by 2024, and as such is planning for future prevention of re-establishment in malaria free provinces. Understanding the receptivity of local areas to malaria allows the appropriate targeting of interventions. Current approaches to assessing receptivity involve collecting entomological data. Forest coverage is known to be associated with malaria risk, as an environment conducive to both vector breeding and high-risk human behaviours. METHODS: Geolocated, anonymized, individual-level surveillance data from 2011 to 2021 from the Thai Division of Vector-Borne Disease (DVBD) was used to calculate incidence and estimated Rc at village level. Forest cover was calculated using raster maps of tree crown cover density and year of forest loss from the publicly available Hansen dataset. Incidence and forest cover were compared graphically and using Spearman's rho. The current foci classification system was applied to data from the last 5 years (2017-2021) and forest cover for 2021 compared between the classifications. A simple risk score was developed to identify villages with high receptivity. RESULTS: There was a non-linear decrease in annual cases by 96.6% (1061 to 36) across the two provinces from 2011 to 2021. Indigenous Annual Parasite Index (API) and approximated Rc were higher in villages in highly forested subdistricts, and with higher forest cover within 5 km. Forest cover was also higher in malaria foci which consistently reported malaria cases each year than those which did not. An Rc > 1 was only reported in villages in subdistricts with > 25% forest cover. When applying a simple risk score using forest cover and recent case history, the classifications were comparable to those of the risk stratification system currently used by the DVBD. CONCLUSIONS: There was a positive association between forest coverage around a village and indigenous malaria cases. Most local transmission was observed in the heavily forested subdistricts on the international borders with Laos and Cambodia, which are where the most receptive villages are located. These areas are at greater risk of importation of malaria due to population mobility and forest-going activities. Combining forest cover and recent case surveillance data with measures of vulnerability may be useful for prediction of malaria recurrence risk.
Assuntos
Florestas , Malária , Tailândia/epidemiologia , Malária/epidemiologia , Malária/transmissão , Humanos , Incidência , Mosquitos Vetores/fisiologia , Animais , Monitoramento Epidemiológico , Erradicação de Doenças/estatística & dados numéricosRESUMO
BACKGROUND: Thailand is approaching local elimination of malaria in the eastern provinces. It has successfully reduced the number of cases over the past decade, but there are persistent transmission hot spots in and around forests. This study aimed to use data from the malaria surveillance system to describe the spatiotemporal trends of malaria in Northeast Thailand and fine-scale patterns in locally transmitted cases between 2011 and 2021. METHODS: Case data was stratified based on likely location of infection and parasite species. Annual Parasite Index per 1000 population (API) was calculated for different categories. Time series decomposition was performed to identify trends and seasonal patterns. Statistically significant clusters of high (hot spots) and low (cold spots) API were identified using the Getis-Ord Gi* statistic. The stability of those hot spots and the absolute change in the proportion of API density from baseline were compared by case type. RESULTS: The total number of confirmed cases experienced a non-linear decline by 96.6%, from 1061 in 2011 to 36 in 2021. There has been a decline in both Plasmodium vivax and Plasmodium falciparum case numbers, with only four confirmed P. falciparum cases over the last two years-a 98.89% drop from 180 in 2011. API was generally higher in Si Sa Ket province, which had peaks every 2-3 years. There was a large outbreak in Ubon Ratchathani in 2014-2016 which had a high proportion of P. falciparum reported. The proportion of cases classified increased over the study period, and the proportion of cases classed as indigenous to the village of residence increased from 0.2% to 33.3%. There were stable hot spots of indigenous and imported cases in the south of Si Sa Ket and southeast of Ubon Ratchathani. Plasmodium vivax hot spots were observed into recent years, while those of P. falciparum decreased to zero in Ubon in 2020 and emerged in the eastern part in 2021, the same year that P. falciparum hot spots in Si Sa Ket reached zero. CONCLUSIONS: There has been a large, non-linear decline in the number of malaria cases reported and an increasing proportion of cases are classed as indigenous to the patient's village of residence. Stable hot spots of ongoing transmission in the forested border areas were identified, with transmission likely persisting because of remote location and high-risk forest-going behaviours. Future efforts should include cross-border collaboration and continued targeting of high-risk behaviours to reduce the risk of imported cases seeding local transmission.
Assuntos
Malária Falciparum , Malária Vivax , Plasmodium falciparum , Tailândia/epidemiologia , Malária Vivax/epidemiologia , Malária Vivax/transmissão , Malária Vivax/prevenção & controle , Malária Falciparum/epidemiologia , Malária Falciparum/transmissão , Malária Falciparum/prevenção & controle , Humanos , Plasmodium vivax/fisiologia , Análise Espaço-Temporal , Erradicação de Doenças/estatística & dados numéricos , Estações do Ano , Hotspot de DoençaRESUMO
BACKGROUND: Magnetic resonance imaging (MRI) allows detailed study of structural and functional changes in the brain in patients with cerebral malaria. METHODS: In a prospective observational study in adult Bangladeshi patients with severe falciparum malaria, MRI findings in the brain were correlated with clinical and laboratory parameters, retinal photography and optic nerve sheath diameter (ONSD) ultrasound (a marker of intracranial pressure). RESULTS: Of 43 enrolled patients, 31 (72%) had coma and 12 (28%) died. MRI abnormalities were present in 79% overall with mostly mild changes in a wide range of anatomical sites. There were no differences in MRI findings between patients with cerebral and non-cerebral or fatal and non-fatal disease. Subtle diffuse cerebral swelling was common (n = 22/43), but mostly without vasogenic oedema or raised intracranial pressure (ONSD). Also seen were focal extracellular oedema (n = 11/43), cytotoxic oedema (n = 8/23) and mildly raised brain lactate on magnetic resonance spectroscopy (n = 5/14). Abnormalities were much less prominent than previously described in Malawian children. Retinal whitening was present in 36/43 (84%) patients and was more common and severe in patients with coma. CONCLUSION: Cerebral swelling is mild and not specific to coma or death in adult severe falciparum malaria. This differs markedly from African children. Retinal whitening, reflecting heterogeneous obstruction of the central nervous system microcirculation by sequestered parasites resulting in small patches of ischemia, is associated with coma and this process is likely important in the pathogenesis.
Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Imageamento por Ressonância Magnética , Malária Cerebral/patologia , Adolescente , Adulto , Idoso , Bangladesh , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nervo Óptico/diagnóstico por imagem , Nervo Óptico/patologia , Estudos Prospectivos , Radiografia , Retina/patologia , Ultrassonografia , Adulto JovemRESUMO
INTRODUCTION: In hospital settings, awareness of, and responsiveness to, COVID-19 are crucial to reducing the risk of transmission among healthcare workers and protecting them from infection. Healthcare professionals can offer insights into the practicalities of infection prevention and control (IPC) measures and on how the guideline aimed to ensure adherence to IPC, including use of personal protective equipment (PPE), could best be delivered during the pandemic. To inform future development of such guideline, this study examined the perspectives of healthcare professionals working in a large hospital during the pandemic regarding their infection risks, the barriers or facilitators to implementing their tasks and the IPC measures to protect their safety and health and of their patients. METHOD: In-depth interviews were conducted with 23 hospital staff coming into contact with possible or confirmed cases of COVID-19, or were at potential risk of contracting the disease, including medical doctors, nurses, virology laboratory staff, and non-medical workers. This qualitative study was carried out as part of a knowledge, attitudes and practice survey to prevent COVID-19 transmission at Ramathibodi Hospital in Thailand. We used content analysis to categorize and code transcribed interview data. Existing IPC guideline and evidence synthesis of organisational, environmental, and individual factors to IPC adherence among healthcare workers were used to guide the development of the interview questions and analysis. FINDING: Factors identified as influencing the use of, and adherence to, prevention measures among healthcare workers included knowledge, perceived risk and concerns about the infection. The extent to which these factors were influential varied based on the medical procedures, among other features, that individuals were assigned to perform in the hospital setting. Beyond availability of PPE and physical safety, ease of and readiness to utilize the equipment and implement IPC measures were crucial to motivate hospital staff to follow the practice guideline. Having a ventilated outdoor space for screening and testing, and interaction through mobile technology, facilitated the performance of healthcare workers while reducing the transmission risk for staff and patients. Adequate training, demonstration of guided practices, and streamlined communications are crucial organisational and management support factors to encourage appropriate use of, and adherence to, implementation of infection prevention and control measures among healthcare workers. CONCLUSION: This finding could help inform the development of recommendations to optimise compliance with appropriate use of these measures, and to improve guidance to reduce HCW's risk of disease in hospital settings. Further study should explore the perceptions and experiences of health professionals in smaller health facilities and community-based workers during the pandemic, particularly in resource-limited settings.
Assuntos
COVID-19 , Médicos , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Tailândia/epidemiologia , Pessoal de Saúde , Hospitais , Recursos Humanos em Hospital , Controle de InfecçõesRESUMO
BACKGROUND: Epidemiological data on malaria in Bangladesh are sparse, particularly on severe and fatal malaria. This hampers the allocation of healthcare provision in this resource-poor setting. Over 85% of the estimated 150,000-250,000 annual malaria cases in Bangladesh occur in Chittagong Division with 80% in the Chittagong Hill Tracts (CHT). Chittagong Medical College Hospital (CMCH) is the major tertiary referral hospital for severe malaria in Chittagong Division. METHODS: Malaria screening data from 22,785 inpatients in CMCH from 1999-2011 were analysed to investigate the patterns of referral, temporal trends and geographical distribution of severe malaria in Chittagong Division, Bangladesh. RESULTS: From 1999 till 2011, 2,394 malaria cases were admitted, of which 96% harboured Plasmodium falciparum and 4% Plasmodium vivax. Infection was commonest in males (67%) between 15 and 34 years of age. Seasonality of malaria incidence was marked with a single peak in P. falciparum transmission from June to August coinciding with peak rainfall, whereas P. vivax showed an additional peak in February-March possibly representing relapse infections. Since 2007 there has been a substantial decrease in the absolute number of admitted malaria cases. Case fatality in severe malaria was 18% from 2008-2011, remaining steady during this period.A travel history obtained in 226 malaria patients revealed only 33% had been to the CHT in the preceding three weeks. Of all admitted malaria patients, only 9% lived in the CHT, and none in the more remote malaria endemic regions near the Indian border. CONCLUSIONS: The overall decline in admitted malaria cases to CMCH suggests recent control measures are successful. However, there are no reliable data on the incidence of severe malaria in the CHT, the most endemic area of Bangladesh, and most of these patients do not reach tertiary health facilities. Improvement of early treatment and simple supportive care for severe malaria in remote areas and implementation of a referral system for cases requiring additional supportive care could be important contributors to further reducing malaria-attributable disease and death in Bangladesh.