IntroductionOne of the most common terrestrial carnivores in the world, the domestic dog (Canis familiaris ) is found on every continent that humans have settled (Gompper 2014). More than 70% of the global dog population (estimated at > 700 million to ~1 billion) comprises of free-ranging dogs (FRD) (Hughes and Macdonald 2013; Gompper 2014). In many developing countries, FRD are associated with the transmission of zoonotic diseases such as rabies, zoonotic visceral leishmaniasis, canine echinococcosis, and soil-borne helminths (Jaleta et al. 2017; Deplazes et al. 2011; Ashford et al. 1998; Quinnell and Courtenay 2009; Carmena and Guillermo 2013). Rabies alone is responsible for an estimated 60,000 human deaths per year worldwide, with a majority of these deaths occurring in Asia and Africa (Hampson et al. 2015). India alone accounts for an estimated 20,000 human rabies deaths per annum (Sudarshan et al. 2007; Hampson et al. 2015).Apart from dog-mediated rabies deaths, dog attacks also result in direct human fatalities in India (e.g. https://www.nationalheraldindia.com/india/stray-dogs-terror-in-sitapur-six-children-killed-in-one-week accessed on 19/Jun/2020). An estimated 20 million people are bitten by dogs every year in India (Gongal and Wright 2011). In addition, dogs are an important and emerging threat for livestock (Home et al. 2017) as well as biodiversity (Vanak and Gompper 2009; Doherty et al. 2017; Belsare, Vanak, and Gompper 2014; Hughes and Macdonald 2013; Gompper 2014). Furthermore, FRD also suffer from poor health, high mortality, and abuse (Jackman and Rowan 2007). There is thus a strong and urgent need to control free-roaming dog populations in India.Efforts to control dog populations in India using a variety of lethal and non-lethal methods have been unsuccessful so far. Lethal methods were implemented haphazardly for many years, but without ancillary measures to restrict access to resources and restricting roaming behaviour, the dog populations rebounded. These methods were also criticized for being unnecessarily cruel and were subsequently outlawed in India. Since 2001, the only legal method of population control, involving capture-neuter-vaccinate-release (Animal Birth Control – ABC) was promulgated. As per the World Organisation for Animal Health (OIE), one of the main objectives of dog population control programmes like ABC is to reduce the abundance of FRD (OIE 2015). However, as several reports have shown, these measures were neither fully implemented nor evaluated (e.g. Totton et al., 2010; Uniyal & Vanak, 2016). Indeed, almost all ABC programs have only targeted urban centres. Even here, model simulations suggest that a sustained and well implemented ABC only program may result in a population reduction of ~70% over a 13-18 year period in the best case scenario of ~85% population coverage (Totton et al. 2010).Dog population management approaches such as the ABC program which mandates surgical sterilisation, requires considerable financial, infrastructural and personnel support. Operationalising any such program therefore requires careful thought and planning for successful implementation. Often however, there is a lack of understanding of the effort required to significantly and sustainably reduce dog populations. Indeed, the general perception is that a one-time or short burst of surgical interventions will result in permanent eradication or “stray dog free” cities (https://www.royalpatiala.in/mission-patiala-to-be-first-stray-dog-free-city-bhullar/ accessed on 22/Jun/2020). Government authorities and non-government organizations (NGOs) routinely report the number of surgeries performed as a measure of success, without any mention of the baseline population size. There is thus a strong need for setting the context and realistic targets, so that the success of the ABC program can be monitored.Population models that allow for simulation of various scenarios are often an effective planning and monitoring tool. If properly parameterised, these can be used to understand the scale of effort needed to achieve a set target reduction in population or to understand that challenges that emerge from improperly planned interventions. However, in India, such models are rarely, if ever, used by government agencies for scenario building and planning. There are several reasons behind this, including a lack of technical expertise, and the perception that such models are the domain of mathematical experts.We have developed an agent-based model that generates a realistic in silico dog population, and projects it over a desired number of years. Model-generated dog populations incorporate individual attributes and characteristics (like age, sex, reproductive status, accessibility, catchability, age-specific mortality) that underpin heterogeneity observed in the real-world free-ranging dog populations. Here we apply the model to evaluate the success as well as cost-effectiveness of dog population management interventions like ABC and also if it achieves the targets necessary for rabies control. Specifically, we examine the effect of ABC interventions on dog abundance, dog recruitment in the population and population-level anti-rabies coverage.
