Electoral Incentives to Combat Mosquito-Borne Illnesses: Experimental Evidence from Brazil


Mosquito-borne illnesses present significant health challenges to the developing world. If citizens are informed about their government’s efforts to combat these diseases, will they reward incumbents who have performed well and punish those who have done poorly at this task? Electoral sanctioning requires that combatting disease be a sufficiently salient concern, which, in turn, is likely to depend upon subjective perceptions of the risks posed by particular illnesses. Epidemics typically prompt stronger risk perceptions than endemic diseases, but where both types circulate jointly, the more familiar endemic disease may determine public reactions. The salience of health threats also varies among individuals; those with a self-interest in prevention or a personal connection to the effects of mosquito-borne illnesses may react more strongly.

This study presents the results of a face-to-face survey experiment in Pernambuco, Brazil, informing subjects about their mayor’s use of federal funds to combat mosquito-borne illnesses such as dengue (an endemic disease) and Zika and chikungunya (both epidemics). We examine the effect of this information on intended vote for the mayor’s reelection. For the full sample, the treatment has no significant effect. However, we find a large and significant punishment effect among voters who know someone affected by microcephaly or the Zika virus. Drawing on survey and focus group evidence, we argue that most voters fail to act upon our treatment information because mosquito control is a low-salience concern primarily associated with endemic rather than epidemic diseases.

Our study constitutes the first experimental evidence as to whether informing citizens about government public health efforts affects voting behavior. Our results suggests that, where similar epidemic and endemic diseases circulate together, informational campaigns aiming to induce electoral accountability should also seek to boost the salience of the information by educating the public about the difference between familiar and newer threats.

World Development