| 1. |
- Ashmore, Polly, et al.
(författare)
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Spatiotemporal and Socioeconomic Risk Factors for Dengue at the Province Level in Vietnam, 2013-2015 : Clustering Analysis and Regression Model
- 2020
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI. - 2414-6366. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Dengue is a serious infectious disease threat in Vietnam, but its spatiotemporal and socioeconomic risk factors are not currently well understood at the province level across the country and on a multiannual scale. We explore spatial trends, clusters and outliers in dengue case counts at the province level from 2011-2015 and use this to extract spatiotemporal variables for regression analysis of the association between dengue case counts and selected spatiotemporal and socioeconomic variables from 2013-2015. Dengue in Vietnam follows anticipated spatial trends, with a potential two-year cycle of high-high clusters in some southern provinces. Small but significant associations are observed between dengue case counts and mobility, population density, a province's dengue rates the previous year, and average dengue rates two years previous in first and second order contiguous neighbours. Significant associations were not found between dengue case counts and housing pressure, access to electricity, clinician density, province-adjusted poverty rate, percentage of children below one vaccinated, or percentage of population in urban settings. These findings challenge assumptions about socioeconomic and spatiotemporal risk factors for dengue, and support national prevention targeting in Vietnam at the province level. They may also be of wider relevance for the study of other arboviruses, including Japanese encephalitis, Zika, and Chikungunya.
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| 2. |
- Chapot, Lorraine, et al.
(författare)
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A Mixed-Methods Approach to Understanding Knowledge of Mosquito-Borne Infections and Barriers for Protection in Hanoi, Vietnam
- 2020
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI. - 2414-6366. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Dengue is a growing problem in Hanoi, with cyclical epidemics of increasing frequency and magnitude. In June 2019, we conducted a cross-sectional survey using mixed methods to investigate how inhabitants of Hanoi perceive and respond to the risk of mosquito-borne diseases (MBD). A total of 117 participants recruited using a stratified random sampling method were interviewed in three districts of Hanoi. Knowledge and practices (KP) regarding MBDs were assessed using a pre-tested questionnaire. Inferential statistics were used to identify factors associated with KP scores and describe the relationship between variables. Additionally, a "risk-mapping" exercise was conducted in a subsample through semi-structured interviews and analyzed qualitatively and quantitatively using the System Effects platform. Factors significantly associated with knowledge scores were education and family history of MBDs. While knowledge and practice scores were found to be positively correlated in the statistical analysis, this was not corroborated by our observations on the field. The results also revealed gaps in knowledge about MBDs and vectors and highlighted a general feeling of powerlessness which prevented the adoption of protective behaviors. Therefore, educational interventions which provide concrete tools to empower communities should have a positive impact on improving vector control.
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| 3. |
- du Cros, P, et al.
(författare)
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Special Issue "Innovation and Evidence for Achieving TB Elimination in the Asia-Pacific Region"
- 2021
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Ingår i: Tropical medicine and infectious disease. - : MDPI AG. - 2414-6366. ; 6:3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The World Health Organization’s (WHO) END-TB strategy has set the world on course to climb the highest of medical mountains by 2035, with a targeted peak of reductions in TB deaths by 95%, TB cases by 90%, and no burden of catastrophic expenses on families due to TB [...]
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| 4. |
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| 5. |
- Gurung, SC, et al.
(författare)
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Comparative Yield of Tuberculosis during Active Case Finding Using GeneXpert or Smear Microscopy for Diagnostic Testing in Nepal: A Cross-Sectional Study
- 2021
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Ingår i: Tropical medicine and infectious disease. - : MDPI AG. - 2414-6366. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- This study compared the yield of tuberculosis (TB) active case finding (ACF) interventions applied under TB REACH funding. Between June 2017 to November 2018, Birat Nepal Medical Trust identified presumptive cases using simple verbal screening from three interventions: door-to-door screening of social contacts of known index cases, TB camps in remote areas, and screening for hospital out-patient department (OPD) attendees. Symptomatic individuals were then tested using smear microscopy or GeneXpert MTB/RIF as first diagnostic test. Yield rates were compared for each intervention and diagnostic method. We evaluated additional cases notified from ACF interventions by comparing case notifications of the intervention and control districts using standard TB REACH methodology. The project identified 1092 TB cases. The highest yield was obtained from OPD screening at hospitals (n = 566/1092; 52%). The proportion of positive tests using GeneXpert (5.5%, n = 859/15,637) was significantly higher than from microscopy testing 2% (n = 120/6309). (OR = 1.4; 95%CI = 1.12–1.72; p = 0.0026). The project achieved 29% additionality in case notifications in the intervention districts demonstrating that GeneXpert achieved substantially higher case-finding yields. Therefore, to increase national case notification for TB, Nepal should integrate OPD screening using GeneXpert testing in every district hospital and scale up of community-based ACF of TB patient contacts nationally.
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| 6. |
- Holmgren, Jan, 1944
(författare)
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An Update on Cholera Immunity and Current and Future Cholera Vaccines
- 2021
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI AG. - 2414-6366. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- Individual resistance to cholera infection and disease depends on both innate host factors and adaptive immunity acquired by a previous infection or vaccination. Locally produced, intestinal-mucosal secretory IgA (SIgA) antibodies against bacterial surface lipopolysaccharide (LPS) O antigens and/or secreted cholera toxins are responsible for the protective adaptive immunity, in conjunction with an effective mucosal immunologic memory that can elicit a rapid anamnestic SIgA antibody response upon re-exposure to the antigen/pathogen even many years later. Oral cholera vaccines (OCVs), based on inactivated Vibrio cholerae whole-cell components, either together with the cholera toxin B subunit (Dukoral (TM)) or administered alone (Shanchol (TM)/Euvichol-Plus (TM)) were shown to be consistently safe and effective in large field trials in all settings. These OCVs are recommended by the World Health Organisation (WHO) for the control of both endemic cholera and epidemic cholera outbreaks. OCVs are now a cornerstone in WHO's global strategy found in "Ending Cholera: A Global Roadmap to 2030." However, the forecasted global demands for OCV, estimated by the Global Alliance for Vaccines and Immunization (GAVI) to 1.5 billion doses for the period 2020-2029, markedly exceed the existing manufacturing capacity. This calls for an increased production capacity of existing OCVs, as well as the rapid introduction of additional and improved vaccines under development.
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| 7. |
- Katak, Ricardo M., et al.
(författare)
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Larvicidal Activities against Aedes aegypti of Supernatant and Pellet Fractions from Cultured Bacillus spp. Isolated from Amazonian Microenvironments
- 2021
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI. - 2414-6366. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- The Aedes aegypti mosquito is the primary vector of Dengue, Chikungunya and Zika causing major problems for public health, which requires new strategies for its control, like the use of entomopathogenic microorganisms. In this study, bacteria from various Amazonian environments were isolated and tested for their pathogenicity to A. aegypti larvae. Following thermal shock to select sporulated Bacillus spp., 77 bacterial strains were isolated. Molecular identification per 16S RNA sequences revealed that the assembled strains contained several species of the genus Bacillus and one species each of Brevibacillus, Klebsiella, Serratia, Achromobacter and Brevundimonas. Among the isolated Bacillus sp. strains, 19 showed larvicidal activity against A. aegypti. Two strains of Brevibacillus halotolerans also displayed larvicidal activity. For the first time, larvicidal activity against A. aegypti was identified for a strain of Brevibacillus halotolerans. Supernatant and pellet fractions of bacterial cultures were tested separately for larvicidal activities. Eight strains contained isolated fractions resulting in at least 50% mortality when tested at a concentration of 5 mg/mL. Further studies are needed to characterize the active larvicidal metabolites produced by these microorganisms and define their mechanisms of action.
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| 8. |
- Li, Wengui, et al.
(författare)
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Participatory and Transdisciplinary Studies of Brucella Infection in Humans and Animals in Yunnan Province, China-Lessons Learned
- 2021
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI. - 2414-6366. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- Brucellosis is an important zoonosis occurring globally. In addition to the risk for disease in humans, the disease causes production losses, since the disease in livestock is characterized by abortion and other reproductive failures. The disease is a public health concern in China, but no information is available on knowledge, perception and awareness of potential risk groups such as farmers, butchers and animal health workers; yet successful control requires compliance of those affected groups to be effective. Following the principles of the Ecohealth approach, emphasis was given to participation of all relevant stakeholders, use of qualitative and quantitative tools, and cross-sectorial collaboration. Data collection included on-farm questionnaires (N = 192) and collection of bulk milk samples of goat (N = 40), cattle (N = 45) and buffalo (N = 41) from farms, as well as serum samples (N = 228) from humans. Milk samples were tested with an ELISA for presence of antibodies, while a serum agglutination test was used for human samples. Qualitative work included 17 focus group discussion (FGD) with villagers and 47 in-depth interviews (IDI) with village animal health workers, doctors, and butchers, focused on knowledge, perception and awareness on zoonoses including brucellosis. Results from questionnaires indicate that abortions are a common problem; cattle with abortion history are kept for further insemination and the milk still consumed or sold. Antibodies against Brucella were detected in cows' (5/45) and goats' (1/40) milk samples, and in human samples (5/126) in Yiliang, while in Mangshi, all buffalo (N = 41) and humans (N = 102) were negative. FGD and IDI results showed an alarmingly low knowledge and awareness on zoonoses; particularly, low awareness about brucellosis was noted, even among the professional groups. Collaboration between village animal health workers and doctors was uncommon. No confirmed brucellosis cases were found in retrospective investigation of hospital and veterinary stations. This study demonstrates the presence of brucellosis in livestock and humans in Yunnan, indicating a non-negligible risk for humans. It is also made apparent that there is a need for increased awareness among both farmers and professionals in order to reduce the risk of zoonotic transmissions.
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| 9. |
- Lindahl, Johanna, et al.
(författare)
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Risk Factors for Brucella Seroprevalence in Peri-Urban Dairy Farms in Five Indian Cities
- 2019
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI AG. - 2414-6366. ; 4:2
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Tidskriftsartikel (refereegranskat)abstract
- Brucellosis is endemic among dairy animals in India, contributing to production losses and posing a health risk to people, especially farmers and others in close contact with dairy animals or their products. Growing urban populations demand increased milk supplies, resulting in intensifying dairy production at the peri-urban fringe. Peri-urban dairying is under-studied but has implications for disease transmission, both positive and negative. In this cross-sectional study, five Indian cities were selected to represent different geographies and urbanization extent. Around each, we randomly selected 34 peri-urban villages, and in each village three smallholder dairy farms (defined as having a maximum of 10 dairy animals) were randomly selected. The farmers were interviewed, and milk samples were taken from up to three animals. These were tested using a commercial ELISA for antibodies against Brucella abortus, and factors associated with herd seroprevalence were identified. In all, 164 out of 1163 cows (14.1%, 95% CI 12.2-16.2%) were seropositive for Brucella. In total, 91 out of 510 farms (17.8%, 95% CI 14.6-21.4%) had at least one positive animal, and out of these, just seven farmers stated that they had vaccinated against brucellosis. In four cities, the farm-level seroprevalence ranged between 1.4-5.2%, while the fifth city had a seroprevalence of 72.5%. This city had larger, zero-grazing herds, used artificial insemination to a much higher degree, replaced their animals by purchasing from their neighbors, were less likely to contact a veterinarian in case of sick animals, and were also judged to be less clean. Within the high-prevalence city, farms were at higher risk of being infected if they had a young owner and if they were judged less clean. In the low-prevalence cities, no risk factors could be identified. In conclusion, this study has identified that a city can have a high burden of infected animals in the peri-urban areas, but that seroprevalence is strongly influenced by the husbandry system. Increased intensification can be associated with increased risk, and thus the practices associated with this, such as artificial insemination, are also associated with increased risk. These results may be important to identify high-risk areas for prioritizing interventions and for policy decisions influencing the structure and development of the dairy industry.
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| 10. |
- Luan, NQV, et al.
(författare)
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Enhanced Private Sector Engagement for Tuberculosis Diagnosis and Reporting through an Intermediary Agency in Ho Chi Minh City, Viet Nam
- 2020
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Ingår i: Tropical medicine and infectious disease. - : MDPI AG. - 2414-6366. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Under-detection and -reporting in the private sector constitute a major barrier in Viet Nam’s fight to end tuberculosis (TB). Effective private-sector engagement requires innovative approaches. We established an intermediary agency that incentivized private providers in two districts of Ho Chi Minh City to refer persons with presumptive TB and share data of unreported TB treatment from July 2017 to March 2019. We subsidized chest x-ray screening and Xpert MTB/RIF testing, and supported test logistics, recording, and reporting. Among 393 participating private providers, 32.1% (126/393) referred at least one symptomatic person, and 3.6% (14/393) reported TB patients treated in their practice. In total, the study identified 1203 people with TB through private provider engagement. Of these, 7.6% (91/1203) were referred for treatment in government facilities. The referrals led to a post-intervention increase of +8.5% in All Forms TB notifications in the intervention districts. The remaining 92.4% (1112/1203) of identified people with TB elected private-sector treatment and were not notified to the NTP. Had this private TB treatment been included in official notifications, the increase in All Forms TB notifications would have been +68.3%. Our evaluation showed that an intermediary agency model can potentially engage private providers in Viet Nam to notify many people with TB who are not being captured by the current system. This could have a substantial impact on transparency into disease burden and contribute significantly to the progress towards ending TB.
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