Uniting mathematics and biology for control of visceral leishmaniasis

The neglected tropical disease (NTD) visceral leishmaniasis (VL) has been targeted by the WHO for elimination as a public health problem on the Indian subcontinent by 2017 or earlier. To date there is a surprising scarcity of mathematical models capable of capturing VL disease dynamics, which are widely considered central to planning and assessing the efficacy of interventions. The few models that have been developed are examined, highlighting the necessity for better data to parameterise and fit these and future models. In particular, the characterisation and infectiousness of the different disease stages will be crucial to elimination. Modelling can then assist in establishing whether, when, and how the WHO VL elimination targets can be met

Sécurité et traitement des données personnelles

La menace du terrorisme conduit fréquemment les gouvernements et leurs agences de renseignement à avoir recours à un éventail de techniques d’enquête spéciales, telle que la collecte d’informations à grande échelle, qui concernent particulièrement les personnes soupçonnées d’activités criminelles comme le terrorisme. En plus des répercussions importantes qu’elles entraînent sur la population en général, ces entreprises d’identification touchent en particulier les demandeurs d’asile et les réfugiés. En effet, ces personnes ont besoin de la protection d’Etats autres que celui dont ils sont ressortissants, et leur sécurité dépend de leur capacité à circuler et à voyager. La vulnérabilité des demandeurs d’asile et des réfugiés est d’autant plus marquée qu’ils dépendent de procédures imposées et qu’ils ont généralement un accès limité au contrôle et aux recours judiciaires. Cet article entend surtout attirer l’attention sur la manière dont ces évolutions risquent d’entraîner des effets négatifs sur les demandeurs d’asile et les réfugiés.The threat of terrorism frequently drives governments and their intelligence agencies to rely on a broad spectrum of special investigation techniques, such as the large-scale collection of information, particularly for persons suspected of criminal activities such as terrorism. Besides the important impact that they have on the general population, these techniques of identification have a particular effect on asylum applicants and refugees. Indeed, these persons seek the protection of states others that the one of which they are nationals, and their security depends on their capacity to move around and travel. The vulnerability of asylum sekers and refugees is all the more important as they depend on mandatory procedures and they generally have a limited access to control mechanisms and effective remedies. This article especially intends to draw attention on the way in which these evolutions can bring about negative effect for asylum seekers and refugees

Visceral Leishmaniasis : Potential for Control and Elimination

Over the past years there has been a steep increase in awareness of visceral leishmaniasis (VL); many large-scale interventions are being implemented and targets for control and elimination have been set. In this thesis the potential of reaching these targets will be explored. To achieve this, the following research questions will be addressed: 1) What is the global health impact when achieving WHOs’ targets for disease elimination and control of 9 neglected tropical diseases, and in particular visceral leishmaniasis? 2) Are veterinarians in the endemic regions of Spain and France aware of the spread of zoonotic VL in Europe and do they implement the guidelines to control the disease? 3) What insights can transmission models provide regarding the feasibility of achieving VL elimination targets on the Indian subcontinent

Awareness and control of canine leishmaniosis: A survey among Spanish and French veterinarians

Zoonotic visceral leishmaniasis (ZVL) is a parasitic disease affecting dogs and humans, which is transmitted by female sandflies. Over the last decade, disease prevalence has increased fivefold in parts of southern Europe, where an estimated 2.5 million dogs are infected. This increase is mainly due to an expansion in sandfly distribution due to climate change and to the greater numbers of dogs travelling among European countries. To combat the spread of ZVL in Europe, international guidelines have been drawn up that describe strategies to prevent, control and monitor the disease. To investigate whether these strategies are being implemented in the field, we conducted an online survey among veterinarians in Spain (endemic for ZVL) and France (south: emerging; north: non-endemic). Of the 889 respondents, 459 veterinarians completed all questions. Although 60% of all veterinarians were aware of the current ZVL increase in Europe, 70% were not familiar with any guidelines for controlling the disease. Most of their preventive and treatment actions were, however, in line with intervention strategies recommended by the guidelines. From the veterinarians in this survey, 76% had received no reports regarding confirmed cases of canine leishmaniosis (CanL) or human visceral leishmaniasis in their region or country. The fact that 88% of confirmed cases of clinical CanL were not reported suggests inadequate disease monitoring and evaluation. We therefore recommend that an easy-to-use and accessible international online network be developed, where both veterinarians and physicians can report confirmed cases of leishmaniosis in dogs and humans. This is crucial for monitoring, controlling and preventing the further spread of ZVL in Europe at regional, national and international level

Modelling the impact of COVID-19-related programme interruptions on visceral leishmaniasis in India

BACKGROUND: In March 2020, India declared a nationwide lockdown to control the spread of coronavirus disease 2019. As a result, control efforts against visceral leishmaniasis (VL) were interrupted. METHODS: Using an established age-structured deterministic VL transmission model, we predicted the impact of a 6- to 24-month programme interruption on the timeline towards achieving the VL elimination target as well as on the increase of VL cases. We also explored the potential impact of a mitigation strategy after the interruption. RESULTS: Delays towards the elimination target are estimated to range between 0 and 9 y. Highly endemic settings where control efforts have been ongoing for 5-8 y are most affected by an interruption, for which we identified a mitigation strategy to be most relevant. However, more importantly, all settings can expect an increase in the number of VL cases. This increase is substantial even for settings with a limited expected delay in achieving the elimination target. CONCLUSIONS: Besides implementing mitigation strategies, it is of great importance to try and keep the duration of the interruption as short as possible to prevent new individuals from becoming infected with VL and continue the efforts towards VL elimination as a public health problem in India

The potential impact of human visceral leishmaniasis vaccines on population incidence

Human visceral leishmaniasis (VL) vaccines are currently under development and there is a need to understand their potential impact on population wide VL incidence. We implement four characteristics from different human VL vaccine candidates into two published VL transmission model variants to estimate the potential impact of these vaccine characteristics on population-wide anthroponotic VL incidence on the Indian subcontinent (ISC). The vaccines that are simulated in this study 1) reduce the infectiousness of infected individuals towards sand flies, 2) reduce risk of developing symptoms after infection, 3) reduce the risk of developing post-kala-azar dermal leishmaniasis (PKDL), or 4) lead to the development of transient immunity. We also compare and combine a vaccine strategy with current interventions to identify their potential role in elimination of VL as a public health problem. We show that the first two simulated vaccine characteristics can greatly reduce VL incidence. For these vaccines, an approximate 60% vaccine efficacy would lead to achieving the ISC elimination target (<1 VL case per 10,000 population per year) within 10 years’ time in a moderately endemic setting when vaccinating 100% of the population. Vaccinating VL cases to prevent the development of PKDL is a promising tool to sustain the low incidence elimination target after regular interventions are halted. Vaccines triggering the development of transient immunity protecting against infection lead to the biggest reduction in VL incidence, but booster doses are required to achieve perduring impact. Even though vaccines are not yet available for implementation, their development should be pursued as their potential impact on transmission can be substantial, both in decreasing incidence at the population level as well as in sustaining the ISC elimination target when other interventions are halted

Variations in visceral leishmaniasis burden, mortality and the pathway to care within Bihar, India

BACKGROUND: Visceral leishmaniasis (VL) has been targeted by the WHO for elimination as a public health problem (< 1 case/10,000 people/year) in the Indian sub-continent (ISC) by 2020. Bihar State in India, which accounts for the majority of cases in the ISC, remains a major target for this elimination effort. However, there is considerable spatial, temporal and sub-population variation in occurrence of the disease and the pathway to care, which is largely unexplored and a threat to achieving the target. METHODS: Data from 6081 suspected VL patients who reported being clinically diagnosed during 2012-2013 across eight districts in Bihar were analysed. Graphical comparisons and Chi-square tests were used to determine differences in the burden of identified cases by season, district, age and sex. Log-linear regression models were fitted to onset (of symptoms)-to-diagnosis and onset-to-treatment waiting times to estimate their associations with age, sex, district and various socio-economic factors (SEFs). Logistic regression models were used to identify factors associated with mortality. RESULTS: Comparisons of VL caseloads suggested an annual cycle peaking in January-March. A 17-fold variation in the burden of identified cases across districts and under-representation of young children (0-5 years) relative to age-specific populations in Bihar were observed. Women accounted for a significantly lower proportion of the reported cases than men (41 vs 59%, P < 0.0001). Age, district of residence, house wall materials, caste, treatment cost, travelling for diagnosis and the number of treatments for symptoms before diagnosis were identified as correlates of waiting times. Mortality was associated with age, district of residence, onset-to-treatment waiting time, treatment duration, cattle ownership and cost of diagnosis. CONCLUSIONS: The distribution of VL in Bihar is highly heterogeneous, and reported caseloads and associated mortality vary significantly across different districts, posing different challenges to the elimination campaign. Socio-economic factors are important correlates of these differences, suggesting that elimination will require tailoring to population and sub-population circumstances

A novel push-pull central-lever mechanism reduces peak forces and energy-cost compared to hand-rim wheelchair propulsion during a controlled lab-based experiment

BACKGROUND: Hand-rim wheelchair propulsion is straining and mechanically inefficient, often leading to upper limb complaints. Previous push–pull lever propulsion mechanisms have shown to perform better or equal in efficiency and physiological strain. Propulsion biomechanics have not been evaluated thus far. A novel push–pull central-lever propulsion mechanism is compared to conventional hand-rim wheelchair propulsion, using both physiological and biomechanical outcomes under low-intensity steady-state conditions on a motor driven treadmill. METHODS: In this 5 day (distributed over a maximum of 21 days) between-group experiment, 30 able-bodied novices performed 60 min (5 × 3 × 4 min) of practice in either the push–pull central lever wheelchair (n = 15) or the hand-rim wheelchair (n = 15). At the first and final sessions cardiopulmonary strain, propulsion kinematics and force production were determined in both instrumented propulsion mechanisms. Repeated measures ANOVA evaluated between (propulsion mechanism type), within (over practice) and interaction effects. RESULTS: Over practice, both groups significantly improved on all outcome measures. After practice the peak forces during the push and pull phase of lever propulsion were considerably lower compared to those in the handrim push phase (42 ± 10 & 46 ± 10 vs 63 ± 21N). Concomitantly, energy expenditure was found to be lower as well (263 ± 45 vs 298 ± 59W), on the other hand gross mechanical efficiency (6.4 ± 1.5 vs 5.9 ± 1.3%), heart-rate (97 ± 10 vs 98 ± 10 bpm) and perceived exertion (9 ± 2 vs 10 ± 1) were not significantly different between modes. CONCLUSION: The current study shows the potential benefits of the newly designed push–pull central-lever propulsion mechanism over regular hand rim wheelchair propulsion. The much lower forces and energy expenditure might help to reduce the strain on the upper extremities and thus prevent the development of overuse injury. This proof of concept in a controlled laboratory experiment warrants continued experimental research in wheelchair-users during daily life

Buitenlui: een aanzienlijke groep potentiële landschapsbeheerders

De daling van het aantal agrarische bedrijven roept de vraag op, wie het cultuurlandschap in de toekomst zal beheren. Want ruim tachtig procent van de vrijkomende agrarische bebouwing verandert van boerderij in woonhuis. In de praktijk vernadert daarmee ook het uiterlijk van het gebouw, van het erf en het landschap. De twaalf provinciale organisaties Landschapsbeheer willen deze nieuwe buitenlui gaan inforemeren en van advies dienen. Met financiële steun van LNV is een project opgestart om de nieuwe doelgroep te leren kennen. Dit artikel geeft gegevens vanuit het Kadaster, gebruik makend van het gegeven: de oppervlakte ligt tussen 0,5 en 5 ha in, erf en huiskavel liggen buiten de bebouwde kom; de percelen zijn in eigendom van particuliere

Post-Kala-Azar Dermal Leishmaniasis as a Reservoir for Visceral Leishmaniasis Transmission

Post-kala-azar dermal leishmaniasis (PKDL) is a parasitic skin infection which can occur after visceral leishmaniasis (VL). Recent xenodiagnosis studies (Mondal et al., Clin. Infect. Dis., 2018) have uncovered the infectiousness of PKDL. When including this in a transmission model, PKDL cases appear as an important reservoir of infection, likely frustrating the VL elimination efforts on the Indian subcontinent