The Effectiveness of Stray Dog Control and Zoonotic Disease Prevention in Global Health: An One Health Approach from Grenada

Keywords

Global Health; Zoonotic Diseases; Rabies; One Health; Stray Dogs.

Introduction

Global health is described as health concerns that transcend national boundaries and governments in addition to call for actions on global forces that determine the health of people [1]. There are several diseases, which transcend national boundaries impacting both animals and humans. Over the past decades, emerging diseases have had a global presence negatively impacting humans. These emerging diseases include HIV/AIDS, Ebola, influenza, hepatitis C, Lyme disease, hantavirus pulmonary syndrome, Severe Acute Respiratory Syndrome (SARS), rabies and Leptospirosis [2]. The burden placed on society by these diseases is so detrimental that the World Health Organization (WHO) has determined a list of pathogens that represent those most likely to cause the greatest impact. The main purpose of this prioritization is to ensure preparedness for the likely development of these diseases and will be reviewed yearly or when necessary [3]. Emerging diseases significantly impacts quality of life and in extreme, fatality. In addition to the negative impacts related to quality of life, the economic burden for the patient and society is also a concern. Lastly, due to the growing incidence of emerging diseases, the resistance to antibiotics and vaccinations to treat the diseases can be a challenge.

Zoonotic diseases are another area within global health that needs public attention. Zoonotic diseases negatively impact human populations via transmission from animals. The most commonly neglected zoonotic diseases are Anthrax, Bovine tuberculosis,Leptospirosis, Brucellosis, Cysticercosis and neurocysticercosis, cystic echinococcosis and rabies [4, 5]. Rabies is the most common zoonotic disease [4]. “Rabies is caused by a virus, which enters through the body through a bite or skin lesion and eventually enters the brain [4].” Approximately, 30-50% of human rabies cases occur among children under 15 years. More than 99% of human deaths as a result of rabies are in developing countries. Post exposure treatment ranges from USD $40-49 in areas where the average daily income is less that USD $2 [6].

Rabies can only be contracted through animal contact via broken skin. Dog bites account for over 10 million injures annually with children having the highest risk. In general, rabies is a concern with dog, cat and monkey bites [7]. Virus transmission via infected dog bites account for approximately 95% of rabies induced human fatalities [8]. In the U.S.dogs bite approximately 4.5 million people each year, approximately 885,00 seek medical care, 30,000 have reconstructive procedures; 3-18% develop infections and 10- 20 fatalities occur [7].

To assist in reducing the incidence of zoonotic diseases experienced by stray dogs, a one health approach to increase awareness and establish control and prevention programs are essential initiatives of the Centers for Disease Control and Prevention (CDC) and WHO. A specific goal of the WHO is for the, “elimination of rabies as a public health problem, defined as zero human rabies deaths [8].” Although there has been an increasing amount of resources and publications regarding the one health concept, it has not been significantly embraced in developing countries where its implementation may result in the greatest impact [9]. While these programs are progressive and promising, the cost prohibits their full implementation in countries of all income levels. An effective dog rabies control program is costly on public health resources among several countries [10]. The estimated annual expenditure for rabies prevention in the U.S. is 300 million, with majority of the funding being spent on dog vaccinations [10]. While zoonotic diseases associated with stray canines transcend national boundaries, stray dog population in Grenada will be emphasized.

Grenada is a small island located in Eastern Caribbean and is home to a significant population of stray dogs. Stray dogs pose a serious public health risk, as they are associated with an increased prevalence of zoonotic disease. Rabies virus causes fatalities in both dogs and humans and has the potential to enter Grenada’s stray dog population, as it is enzootic on the main island due to the presence of the reservoir host, the mongoose Herpestes auropunctatus [11, 12]. Leptospirosis is another disease of public health significance in Grenada, and evidence suggests dogs can serve as a reservoir host for the Leptospira serovar canicola [13]. In a 2010 study performed in Grenada, antibodies to American trypanosomiasis were found in 4.3% of the study population of dogs, which act as a reservoir for the disease. [14] In another study performed in Grenada in 2014, the seroprevalence for this parasite increased to 10.5%, with 76.2% of these positive results coming from stray dogs and the remainder from owned dogs [15]. This pathogen may be spread to humans via the Triatome bug and cause the development of Chagas disease [16]. Grenada is a popular tourist location, which makes the spread of zoonotic diseases to humans a global health concern.

In addition to zoonotic disease, stray dogs in Grenada also cause damage to livestock, are a considerable public nuisance due to noise and fecal pollution, and can be a cause of and traffic accidents due to their presence on roadways. In a tourism-driven economy such as Grenada’s, the negative impact that the latter factors may have should also be considered. In 2002, the “Dogs (Registration and Control)” Act was passed by the Parliament of Grenada in order to reduce the spread of zoonotic disease. This legislation serves as the foundation for Grenada’s Stray Dog Control Program (SDCP), which was launched by the Ministry of Health in 2007.

This justifies the need for ongoing prevention and control investigation and protocol development globally surrounding stray dog management. Inadequate literacy among populations regarding zoonotic diseases, importance of dog vaccination and registration, emphasizes the need for an interprofessional approach among medical and veterinary providers to educate the public. The purpose of this study is to evaluate Grenada’s stray dog control practices and obtain the knowledge level of stakeholders involved with SDCP. The operational hypothesis is, limitations in the SDCP compromised the effectiveness to decrease stray dog numbers, promote overall dog health, and prevent dog-associated disease in humans.

Materials and Methods

This qualitative study consisted of reviewing and collecting the following data in Grenada: regulatory and legislative documents, quantitative analysis of documented dog registration and vaccinations and interviews from key stakeholders associated with SDCP.

Legislative and regulatory documents were analyzed and pertinent similarities and differences summarized in a table consisting of three parallel columns. The first document was the World Organization for Animal Health’s (OIE) “Guidelines on stray dog population control,” obtained from the OIE website5. The second set of documents was the “Dogs (Registration and Control)” Act 24 found in Laws of Grenada 2002. The third column noted which parts of Act 24 are currently being enforced, as described by the Senior Environmental Health Officer in charge of SDCP activities (Table 1).

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Table 1:

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Table 1. Review of Stray Dog Policy

Quantitative data analysis on registration/vaccination rates, number of dog complaints filed, number of dogs captured and outcome of dog captures for the years 2008-2012 was performed. Totals and trends were identified and described.

Lastly, interviews with key stakeholders (n=14) from three groups directly involved with dog population control; The Grenada Society for Prevention of Cruelty to Animals; St. George’s University Small Animal Clinic; and SDCP’s Dog Control Unit. The stakeholders were recruited through a snowball sampling process where persons were identified based on a referral process as one stakeholder participant recommended another to be interviewed. Community members who have made use of the SDCP’s services were also interviewed (n=5). Interview recordings were transcribed and analyzed to identify emerging themes. These themes were ranked according to the frequency with which they appeared, and main concepts identified by linking related themes.

Results

Results demonstrated that Act 24 of 2002 provided adequate framework for stray dog control. However, limitations in resources, due primarily to mandatory fiscal reductions in government public services in the aftermath of Hurricane Ivan in 2004, have to date resulted in only partial implementation of legislative provisions. Registration of dogs has been ongoing during the program, yet there has been an annual reduction in the number of dogs registered/vaccinated by the SDCP. Dog complaints and captures have increased during the same time period. There was a decrease in the number of dogs registered/vaccinated, (5751 dogs in 2008), (3721 in 2009), (3435 in 2010), (2781 in 2011) and (1971 in 2012). Meanwhile there was a steady increase in both dogs captured and dog related complaints (Figure 1). The majority of dogs captured by the SDCP control officers were euthanized, while a small number were adopted out from the SDCP facility or from the GSPCA kennel, some were returned to the owner, and a small number died while held in the SDCP facility (Figure 2).

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Figure 1:

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Figure 1: Total annual counts of dogs Registered/vaccinated, dogs captured,and dog related complaints for the years 2008-2012.

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Figure 2:

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Figure 2: Outcome of dog captures for all dogs captured between 2008-2012

Saturation of data was achieved in interviews with both Stakeholders and Program Users. Themes that emerged from interviews were prioritized in accordance with the frequency with which they appeared, in interview transcripts (Tables 2 and 3). The following themes were most frequently mentioned in the interviews: community education (52 times), dog ownership (50 times), non-governmental involvement (35 times) and SDCP responsibility (30 times).

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Table 2:

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Table 2. Themes Ranked by Frequency Mentioned

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Table 3:

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Table 3. Emerging themes with description and representation interview questions

Discussion

Zoonotic diseases are obstacles to developing countries where resources for managing animal illnesses are a challenge. As a result, humans suffer from the transmission of diseases between these two distinct populations. As with any concern related to human health, an inter professional approach is needed between medical and veterinary providers. Developing community health systems as a whole is an essential aspect of the one health mentality and Developing community health systems as a whole is an essential aspect of the one health mentality and embodies this inter professional approach. To appreciate the possible positive effects of the one health approach, it must be coupled with a one world approach. Devastating diseases do not obey international boundaries and this must be recognized to properly prevent future outbreaks [9]. When zoonotic diseases affect humans, an overall impact to society occurs. In order to minimize this problem a control and prevention protocol for animals globally must be established and followed by all stakeholders.

In order to increase population awareness of zoonotic diseases and provide governmental support to countries, FAO, OIE and WHO are international organizations that have proposed fiveyear action items for countries to follow. The overall five-year target is to “Adopt measured behaviors, policies and/or practices that minimize the spillover of zoonotic diseases from animals to human populations [17].” Some of the five-year action items include:

“Emphasize One Health approaches across all relevant sectors of government with the goal of detecting and controlling zoonotic threats while they are still in animal populations.

Implement joint IHR and PVS training programs for human and animal health service

Increase the compatibility of existing animal and human diagnostics and surveillance data fields, avoiding the creation of new data systems wherever possible

Introduce and advice national multi-sectoral policies and regulatory guidelines promoting poultry and livestock production and marketing practices that minimize the risk of zoonotic disease emergence, including food safety policies and guidelines as well as legislation reinforcing veterinary supervision of the use of antibiotics in animals

Support the implementation of national architecture for real-time bio-surveillance, spanning animal and human populations to support disease monitoring, reporting and analysis via bio-surveillance of high-risk wildlife groups (i.e., birds, bats, etc.)

Actively address the proposal of core competencies and systems requirements (e.g., laboratory methods, surveillance data fields) for implementation of the surveillance system.

Enhance, link, and increase analytic capability within disease reporting systems (WHO, WAHIS), to ensure that WHO, FAO, and OIE receive pertinent information.

Introduce an operational framework that supports multi-sectoral notification for outbreaks of suspected zoonotic origin in the early stage of emergence (prior to efficient human-to-human transmission).

Introduce systems that promote complementary research, for public health purposes, and analysis within and across countries for enhanced prevention, detection and response activities for emerging zoonotic diseases [17].”

In Grenada, expansion of SDCP services is needed to reduce free-roaming dogs in public places and disease risk to humans. A positive response from program users suggested that the SDCP is well-received by the community. Interview data recommended that integration among stakeholders and increased access to the program's services in rural communities is needed. Community education on stray dog control regulations associated zoonotic diseases risks and prevention and responsible pet ownership were identified as key areas for continued program development. These findings have implication for further policy development to reduce global health risks associated with zoonotic diseases found in stray dogs.

Acknowledgement & Declarations

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