Heme Oxygenase-1 Induction by Blood-Feeding Arthropods Controls Skin Inflammation and Promotes Disease Tolerance.

Hematophagous vectors lacerate host skin and capillaries to acquire a blood meal, resulting in leakage of red blood cells (RBCs) and inflammation. Here, we show that heme oxygenase-1 (HO-1), a pleiotropic cytoprotective isoenzyme that mitigates heme-mediated tissue damage, is induced after bites of sand flies, mosquitoes, and ticks. Further, we demonstrate that erythrophagocytosis by macrophages, including a skin-residing CD163+CD91+ professional iron-recycling subpopulation, produces HO-1 after bites. Importantly, we establish that global deletion or transient inhibition of HO-1 in mice increases inflammation and pathology following Leishmania-infected sand fly bites without affecting parasite number, whereas CO, an end product of the HO-1 enzymatic reaction, suppresses skin inflammation. This indicates that HO-1 induction by blood-feeding sand flies promotes tolerance to Leishmania infection. Collectively, our data demonstrate that HO-1 induction through erythrophagocytosis is a universal mechanism that regulates skin inflammation following blood feeding by arthropods, thus promoting early-stage disease tolerance to vector-borne pathogens.

Understanding risk communication for prevention and control of vector-borne diseases: A mixed-method study in Curaçao.

BACKGROUND: Risk communication (RC) is an essential tool for the prevention and control of diseases as it impacts risk perception, increases awareness and might change behaviour. It is the interactive exchange of information about risks among experts and people. Effective RC can minimize the impact that diseases such as dengue, chikungunya and Zika have on populations. This study aimed to understand RC regarding vector-borne diseases in its social context and from the viewpoint of the audience to strengthen RC strategies in Curaçao. METHODS: In 2015, a cross-sectional mixed-method study applying focus group discussions (n = 7), in-depth interviews (n = 20) and a structured survey questionnaire (n = 339) was done in Curaçao. The study was designed based on the Health Belief Model and the Theory of Planned Behaviour. In addition, the Social Amplification of Risk Framework and the theory of cultural schemas were applied to understand RC in the social context. RESULTS: Television, radio and newspapers were the most important channels of information regarding dengue and chikungunya. Moreover, individuals also reported receiving information via social media, the internet and family/friends. Interestingly, the use of internet to obtain information diminished with age, while females were more likely to use internet compared to men. These key findings were statistically significant. An important outcome was that the risk perception towards chikungunya at the beginning of the outbreak was attenuated. This might be due to the (perceived) lack of RC before the epidemic. This same risk perception was amplified later during the outbreak by the increased exposure to information. Lastly, we show how cultural schemas influence people's perception regarding preventive measures and treatment of chikungunya and dengue. CONCLUSIONS: Data obtained emphasise the importance of understanding the user of media platforms and sharing information in a timely fashion through a transparent process with the content that convinces people of the seriousness of the matter.