The global burden of neglected zoonotic diseases: Current state of evidence

A framework for quantifying the multisectoral burden of animal disease to support decision making

Animal diseases have wide-ranging impacts in multiple societal arenas, including agriculture, public health and the environment. These diseases cause significant economic losses for farmers, disrupt food security and present zoonotic risks to human populations. Additionally, they contribute to antimicrobial resistance and a range of environmental issues such as greenhouse gas emissions. The societal and ecological costs of livestock diseases are frequently underrepresented or unaddressed in policy decisions and resource allocations. Social cost-benefit analysis (SCBA) offers a comprehensive framework to evaluate the broad impacts of animal diseases across different sectors. This approach aligns with the One Health concept, which seeks to integrate and optimize the health of humans, animals and the environment. Traditional economic evaluations often focus narrowly on profit maximization within the livestock sector, neglecting wider externalities such as public health and environmental impacts. In contrast, SCBA takes a multi-sectoral whole-system view, considering multiple factors to guide public and private sector investments toward maximizing societal benefits. This paper discusses three separate sector specific (Animal health, Human health, Environmental health) methodologies for quantifying the burden of animal diseases. It then discusses how these estimates can be combined to generate multisectoral estimates of the impacts of animal diseases on human societies and the environment using monetary values. Finally this paper explores how this framework can support the evaluation of interventions from a One Health perspective though SCBA. This integrated assessment framework supports informed decision-making and resource allocation, ultimately contributing to improved public health outcomes, enhanced animal welfare, and greater environmental sustainability.

Health and economic impacts of Lassa vaccination campaigns in West Africa

Lassa fever is a zoonotic disease identified by the World Health Organization (WHO) as having pandemic potential. This study estimates the health-economic burden of Lassa fever throughout West Africa and projects impacts of a series of vaccination campaigns. We also model the emergence of 'Lassa-X'-a hypothetical pandemic Lassa virus variant-and project impacts of achieving 100 Days Mission vaccination targets. Our model predicted 2.7 million (95% uncertainty interval: 2.1-3.4 million) Lassa virus infections annually, resulting over 10 years in 2.0 million (793,800-3.9 million) disability-adjusted life years (DALYs). The most effective vaccination strategy was a population-wide preventive campaign primarily targeting WHO-classified 'endemic' districts. Under conservative vaccine efficacy assumptions, this campaign averted $20.1 million ($8.2-$39.0 million) in lost DALY value and $128.2 million ($67.2-$231.9 million) in societal costs (2021 international dollars ($)). Reactive vaccination in response to local outbreaks averted just one-tenth the health-economic burden of preventive campaigns. In the event of Lassa-X emerging, spreading throughout West Africa and causing approximately 1.2 million DALYs within 2 years, 100 Days Mission vaccination averted 22% of DALYs given a vaccine 70% effective against disease and 74% of DALYs given a vaccine 70% effective against both infection and disease. These findings suggest how vaccination could alleviate Lassa fever's burden and assist in pandemic preparedness.

One health intervention for the control and elimination of scrub typhus, anthrax, and brucellosis in Southeast Asia: a systematic review

The "One Health" (OH) approach, introduced in 2004, integrates human, animal, and environmental health to address emerging and re-emerging diseases. This study evaluates OH strategies used by southeast Asian countries for brucellosis, anthrax, and scrub typhus. We systematically searched Medline, EMBASE, ProQuest, and EBSCO-CINHL up to May 11, 2023, screened 711 articles, and included ten studies (five on brucellosis, four on anthrax, and two on scrub typhus). Key strategies identified included intersectoral collaboration, vaccination initiatives, and comprehensive surveillance systems for both humans and animals. Additional efforts were noted in improving health infrastructure and implementing preventive measures. The review underscores that although some progress has been made, a more integrated OH approach is crucial for effective prevention and management of zoonotic diseases in southeast Asia, highlighting the need for enhanced collaboration and coordinated efforts across sectors.

Anthrax in Humans, Animals, and the Environment and the One Health Strategies for Anthrax Control

Anthrax is a notorious disease of public health importance caused by Bacillus anthracis. The causative agent can also be used as a biological weapon. Spores of these bacteria can sustain extreme environmental conditions and remain viable in soil for decades. Domestic and wild ruminants are highly susceptible to this pathogen, which usually presents as a peracute to acute disease. In humans, cutaneous anthrax is frequent but pulmonary and enteric anthrax are more serious. Humans, animals, and the environment are all involved, making anthrax a perfect target for a One Health approach. The environment plays a key role in disease transmission. At a time when the One Health concept is not mere slogans, collaborative efforts of medical professionals, veterinarians, and environmental scientists will be valuable for the prevention and control of this disease. In this review, we discussed the transmission dynamics of anthrax in the environment, animals, and humans, as well as One Health strategies to control and prevent anthrax.

Health and economic impacts of Lassa vaccination campaigns in West Africa

Lassa fever is a zoonotic disease identified by the World Health Organization (WHO) as having pandemic potential. This study estimates the health-economic burden of Lassa fever throughout West Africa and projects impacts of a series of vaccination campaigns. We also model the emergence of "Lassa-X" - a hypothetical pandemic Lassa virus variant - and project impacts of achieving 100 Days Mission vaccination targets. Our model predicted 2.7M (95% uncertainty interval: 2.1M-3.4M) Lassa virus infections annually, resulting over ten years in 2.0M (793.8K-3.9M) disability-adjusted life years (DALYs). The most effective vaccination strategy was a population-wide preventive campaign primarily targeting WHO-classified "endemic" districts. Under conservative vaccine efficacy assumptions, this campaign averted $20.1M ($8.2M-$39.0M) in lost DALY value and $128.2M ($67.2M-$231.9M) in societal costs (International dollars 2021). Reactive vaccination in response to local outbreaks averted just one-tenth the health-economic burden of preventive campaigns. In the event of Lassa-X emerging, spreading throughout West Africa and causing approximately 1.2M DALYs within two years, 100 Days Mission vaccination averted 22% of DALYs given a vaccine 70% effective against disease, and 74% of DALYs given a vaccine 70% effective against both infection and disease. These findings suggest how vaccination could alleviate Lassa fever's burden and assist in pandemic preparedness.

Control of companion animal parasites and impact on One Health

The last decades have witnessed an increase in the global population and movements of companion animals, contributing to changes in density and distribution of pet parasites. Control of companion animal parasites (CAPs) becomes increasingly relevant because of the intensifying human-animal bond. Parasites impact on the health of humans and their pets, but also of wildlife and the environment. We conducted a qualitative review on the current advancements, gaps and priorities for the monitoring and treatment of CAPs with a focus on securing public health. There is a need to raise awareness, coordinate global surveillance schemes and better quantify the impact of companion animal parasites on One Health.

Quantifying the neglected: Initial estimation of the global burden and economic impact of human toxocariasis

Toxocariasis is a parasitic zoonotic infection caused by Toxocara spp., ascarid nematodes of companion animals (dogs and cats) affecting people in both high-income and low/middle-income countries. Toxocariasis can manifest as several distinct syndromes. The most frequent, often termed common toxocariasis, is a self-limiting and mild febrile illness. Ocular and visceral larva migrans are severe disease manifestations affecting the eye and other internal organs, respectively, but their reported occurrence is rare. The vast majority of symptomatic cases are thought due to common toxocariasis, which has also been associated with cognitive impairment in children. Few studies to date have sought to quantity the health burden of toxocariasis in humans. In this study we provide a preliminary estimation using the Disability-Adjusted Life Year (DALY) approach. We estimate a total of 23,084 DALYs are lost annually in 28 selected countries due to common toxocariasis. Extrapolating based on a global average seroprevalence rate of 19%, we estimate 91,714 DALYs per year are lost across all countries due to toxocariasis, of which 40,912 are attributable to less severe forms, i.e. common toxocariasis, and 50,731 to cognitive impairment in children. Clinically diagnosed and reported ocular and visceral larva migrans represent a small proportion of estimated total health burden. We also found a positive correlation at national level between prevalence in cats or dogs and seroprevalence in humans, but no correlation between estimated soil contamination and seroprevalence in humans. Finally, we estimate the potential economic impact of toxocariasis in selected countries at 2.5 billion USD per annum, from costs of medical treatment and lost income. These preliminary estimates should serve as a call to action for further research and evidence-based measures to tackle toxocariasis.

Knowledge, attitudes and practices regarding zoonotic diseases among cat and dog owners in Bangladesh

The close relationship between human and companion animals like cats and dogs raises public health concerns regarding the potential transmission of zoonotic diseases in Bangladesh. The study aimed to evaluate the cat and dog owners' knowledge, attitudes, practices, and risk perception concerning zoonotic diseases for designing effective interventions and reducing disease transmission. A cross-sectional survey was conducted among 480 pet owners in various region of Bangladesh. For data collection, a structured, closed-ended questions were implemented. The data collection was anonymous and individuals were chosen through a random selection method. Responses were classified to evaluate comprehensive knowledge, using a threshold value of ≥65%. Quantitative score was created to measure Knowledge, Attitudes, and Practices, and these scores were divided into categories of good and poor knowledge, positive and negative attitudes, as well as correct and incorrect practices. The analysis included the application of both descriptive statistics and logistic regression analysis. The findings showed that females made up more than half of the survey participants (55.2%), with the predominant pet owned being cats (73.1%). Overall, only a small portion (21.25%) of the survey respondents demonstrated good knowledge about the topic as measured by a dichotomous outcome. A larger proportion of participants (84.58%) exhibited a positive attitude towards zoonotic diseases. However, when it came to correct practices, about one-third (29.79%) of performed satisfactorily. It is noteworthy that 90.4% of the participants exhibited a high level of understanding regarding the transmission of rabies through dog bites. The knowledge and practices of owners were markedly impacted by their education, occupation, and geographic location. Furthermore, 48.1% identified 'social media' as their primary source of information, and 80.0% regarded vaccination as a preventive measure. The study reveals gaps in knowledge and practices of risks regarding zoonotic diseases among pet owners in Bangladesh. It is crucial to implement focused educational initiatives and preventative measures to effectively tackle gaps in knowledge concerning zoonotic diseases and to avert potential infections.

Modern technologies and solutions to enhance surveillance and response systems for emerging zoonotic diseases

Background

Zoonotic diseases originating in animals pose a significant threat to global public health. Recent outbreaks, such as coronavirus disease 2019 (COVID-19), have caused widespread illness, death, and socioeconomic disruptions worldwide. To cope with these diseases effectively, it is crucial to strengthen surveillance capabilities and establish rapid response systems.

Aim

The aim of this review to examine the modern technologies and solutions that have the potential to enhance zoonotic disease surveillance and outbreak responses and provide valuable insights into how cutting-edge innovations could be leveraged to prevent, detect, and control emerging zoonotic disease outbreaks. Herein, we discuss advanced tools including big data analytics, artificial intelligence, the Internet of Things, geographic information systems, remote sensing, molecular diagnostics, point-of-care testing, telemedicine, digital contact tracing, and early warning systems.

Results

These technologies enable real-time monitoring, the prediction of outbreak risks, early anomaly detection, rapid diagnosis, and targeted interventions during outbreaks. When integrated through collaborative partnerships, these strategies can significantly improve the speed and effectiveness of zoonotic disease control. However, several challenges persist, particularly in resource-limited settings, such as infrastructure limitations, costs, data integration and training requirements, and ethical implementation.

Conclusion

With strategic planning and coordinated efforts, modern technologies and solutions offer immense potential to bolster surveillance and outbreak responses, and serve as a critical resource against emerging zoonotic disease threats worldwide.