Uncertainty in times of medical emergency: Knowledge gaps and structural ignorance during the Brazilian Zika crisis
Kelly, Ann H. ; Lezaun, Javier ; Löwy, Ilana ; Matta, Gustavo Corrêa ; Oliveira Nogueira, Carolina de; Rabello, Elaine Teixeira - \ 2020
Social Science and Medicine 246 (2020). - ISSN 0277-9536
Brazil - Emergency research - Public health emergency - Uncertainty - Zika
Uncertainty was a defining feature of the Brazilian Zika crisis of 2015–2016. The cluster of cases of neonatal microcephaly detected in the country's northeast in the second half of 2015, and the possibility that a new virus transmitted by Aedes mosquitoes was responsible for this new syndrome, created a deep sense of shock and confusion in Brazil and around the world. When in February 2016 the WHO declared a Public Health Emergency of International Concern (PHEIC), it noted that it did so on the basis of what was not known about the virus and its pathogenic potential. To better understand the role that non-knowledge played in the unfolding of the Brazilian Zika crisis we differentiate between three different kinds of uncertainty: global health uncertainty, public health uncertainty, and clinical uncertainty. While these three forms of uncertainty were difficult to disentangle in the early weeks of the crisis, very soon each one began to trace a distinct trajectory. Global health uncertainty centered on the question of the causative link between Zika virus infection and congenital malformations, and was declared resolved by the time the PHEIC was lifted in November 2016. Public health and clinical uncertainty, in contrast, persisted over a longer period of time and did, in some important ways, become entrenched. This taxonomy of uncertainties allows us to explore the systematic nonproduction of knowledge in times of medical emergency, and suggests structural limitations in the framework of “emergency research” that global health institutions have developed to deal with unexpected threats.
Predicting the spatial dynamics of Wolbachia infections in Aedes aegypti arbovirus vector populations in heterogeneous landscapes
Hancock, Penelope A. ; Ritchie, Scott A. ; Koenraadt, Constantianus J.M. ; Scott, Thomas W. ; Hoffmann, Ary A. ; Godfray, Charles - \ 2019
Journal of Applied Ecology 56 (2019)7. - ISSN 0021-8901 - p. 1674 - 1686.
arbovirus - dengue - gene drive - spatial spread - wAlbB - wMel - wMelPop - Zika
A promising strategy for reducing the transmission of dengue and other arboviral human diseases by Aedes aegypti mosquito vector populations involves field introductions of the endosymbiotic bacteria Wolbachia. Wolbachia infections inhibit viral transmission by the mosquito, and can spread between mosquito hosts to reach high frequencies in the vector population. Wolbachia spreads by maternal transmission, and spread dynamics can be variable and highly dependent on natural mosquito population dynamics, population structure and fitness components. We develop a mathematical model of an A. aegypti metapopulation that incorporates empirically validated relationships describing density-dependent mosquito fitness components. We assume that density dependent relationships differ across subpopulations, and construct heterogeneous landscapes for which model-predicted patterns of variation in mosquito abundance and demography approximate those observed in field populations. We then simulate Wolbachia release strategies similar to that used in field trials. We show that our model can produce rates of spatial spread of Wolbachia similar to those observed following field releases. We then investigate how different types of spatio-temporal variation in mosquito habitat, as well as different fitness costs incurred by Wolbachia on the mosquito host, influence predicted spread rates. We find that fitness costs reduce spread rates more strongly when the habitat landscape varies temporally due to stochastic and seasonal processes. Synthesis and applications: Our empirically based modelling approach represents effects of environmental heterogeneity on the spatial spread of Wolbachia. The models can assist in interpreting observed spread patterns following field releases and in designing suitable release strategies for targeting spatially heterogeneous vector populations.
Chikungunya and zika virus Vaccines
Metz, Stefan W. ; Pijlman, Gorben P. - \ 2018
In: Chikungunya and Zika Viruses / Higgs, S., Vanlandingham, D.L., Powers, A.M., Elsevier - ISBN 9780128118665 - p. 347 - 365.
Animal models - Arbovirus - Chikungunya - Clinical trials - Immunity - Mosquito - Vaccines - Zika
The spread of chikungunya and Zika viruses can be controlled by vaccination of human populations. Classical inactivated virus formulations and live attenuated viruses have demonstrated different rates of success. The molecular toolbox is now advanced enough to explore the potential of novel vaccine modalities that are in different stages of development and (pre)clinical testing. Here, we describe the state of the art of classical and next-generation vaccine platforms including viral vectored and chimeric vaccines, virus-like particles (VLPs), and nucleic acid (DNA, RNA), and subunit vaccines. We review their development, characterization, immunogenicity, and safety and we provide a future outlook for these vaccines to alleviate the burden of disease in areas where mosquitoes continue to spread these pathogens. Finally, we indicate particular challenges for chikungunya and Zika vaccines to proceed though clinical trials and become commercially available.
An analysis of community perceptions of mosquito-borne disease control and prevention in Sint Eustatius, Caribbean Netherlands
Leslie, Teresa E. ; Carson, Marianne ; Coeverden, Els van; Klein, Kirsten De; Braks, Marieta ; Krumeich, Anja - \ 2017
Global Health Action 10 (2017)1. - ISSN 1654-9880
Chikungunya - community participation - Dengue - prevention - Zika
BACKGROUND: In the Caribbean, mosquito-borne diseases are a public health threat. In Sint Eustatius, dengue, Chikungunya and Zika are now endemic. To control and prevent mosquito-borne diseases, the Sint Eustatius Public Health Department relies on the community to assist with the control of Aedes aegypti mosquito. Unfortunately, community based interventions are not always simple, as community perceptions and responses shape actions and influence behavioural responses Objective: The aim of this study was to determine how the Sint Eustatius population perceives the Aedes aegypti mosquito, mosquito-borne diseases and prevention and control measures and hypothesized that increased knowledge of the virus, vector, control and prevention should result in a lower AQ1 prevalence and incidence of mosquito-borne diseases.
METHODS: This study was conducted in Sint Eustatius island in the Eastern Caribbean. We combined qualitative and quantitative designs. We conducted interviews and focus groups discussions among community member and health professional in 2013 and 2015. We also conducted cross-sectional survey to assess local knowledge on the vector, virus, and control and prevention.
RESULTS: The population is knowledgeable;
DISCUSSION: In the context of Sint Eustatius, when controlling the Aedes population it may be a strategic option to focus on the household level rather than the community and build collaborations with households by supporting them when they actively practice mosquito 25 control. To further increase the level of knowledge on the significance of mosquito-borne diseases, it may also be an option to contextualize the issue of the virus, vector, prevention and control into a broader context.
CONCLUSION: As evidenced by the increasing number of mosquito-borne diseases on the island, it appears that knowledge amongst the lay community may not be transferred into 30 action. This may be attributed to the perception of the Sint Eustatius populations that mosquitoes and the viruses they carry are not a high priority in comparison to other health concerns.