Zoonoses and Geomedical Factors
Jul Låg in Geomedicine, 2017
Trypanomosiasis is any disease caused by a trypanosome. Many of these diseases are zoonoses. They are transmitted by different arthropods. According to Greenham,1 trypanosomiasis affected 10 million people, and has dogs, pigs, cattle, game animals, and many rodents as reservoir hosts. Chagas disease in South America is produced by a trypanosome whose target organ is the heart in man, while the different trypanosoma of the brucei group in Africa have as their main target organ the central nervous system of man. In Africa, the main transmitters of the diseases are different tse-tse flies (Glossina), horseflies, (Tabanidae), stomoxys, and some mosquitoes may to some extent be transmitters. In Africa, some large breeding places of the tse-tse fly have been cleared of bush and dusted with pesticides. But the fight has been hampered by the emergence of insecticide-resistant flies. At the same time, ecological problems have resulted from the use of insecticides. It is important to remove bushes and trees near the living places of man to keep the tse-tse flies away. In tropical America, trypanomiasis is mainly transmitted by assasin bugs (Triotoma infestans). The elimination of the Chagas is a matter of personal and public hygiene and housing. The economic and social improvement of common man is perhaps most important for a solution of the Chagas problem.
Inflection points
J. Michael Ryan in COVID-19, 2020
Zoonosis occurs when a virus leaps from a nonhuman animal to a human, successfully establishing itself as an infectious presence that can cause mild or severe symptoms, or even death. Outside the worlds of virologists, veterinarians, ecologists, and public health officials, zoonosis is largely an unfamiliar word. Bubonic plague is a zoonosis, so too were the 1918 influenza pandemic, all influenzas, the swine flu, HIV, Ebola, SARS, MERS, Lyme disease, Marburg, and rabies (Quammen 2012; CDC 2020a; NIAID 2020). Different from predators that eat their prey from the outside, viruses are small and eat their prey from within. Under ordinary conditions, it is a natural occurrence. But, as Quammen (2012) pointed out, conditions are not always ordinary. Aberrations occur, circumstances change, and with them, the needs and opportunities for pathogens change, too.
Responding to Uncertainty
Kevin Bardosh in One Health, 2016
Ghana’s public health priorities are oriented around known threats, like cholera, HIV/AIDS, meningitis, hepatitis, TB and malaria. The focus on these priorities crowds out an interdisciplinary approach to zoonoses. As stated by one medic, ‘zoonotic infections, we leave that to veterinarians’. Nonetheless, officials at 37 Military Hospital and Ghana Public Health Services recognized zoonotic disease as a potential area of concern: ‘Zoonosis is becoming increasingly more important in the world, you always wonder what the next infection will be, where the next outbreak will come from.’ Their framing focuses on human health as the most important variable, as articulated by one very senior military official: ‘Human heath should triumph in the preservation of bats versus humans.’ The primary public health zoonotic concerns reported in 2012 concerned influenzas, rabies, yellow fever and Lassa fever.
Zoonotic fungal diseases and animal ownership in Nigeria
Published in Alexandria Journal of Medicine, 2018
Adebowale I. Adebiyi, Daniel O. Oluwayelu
Zoonoses are diseases of animal origin, usually caused by viruses, bacteria, fungi and parasites which can be naturally transmitted to humans.1 They have been known for many centuries, and account for the majority of emerging and re-emerging infectious diseases, globally.2,3. It has been reported that 75% of all emerging infectious disease pathogens are zoonotic, originating principally from wildlife.2,4 Indeed, zoonotic infections have emerged as a burden for millions of people in recent years, due to re-emerging or novel pathogens often causing outbreaks in the developing world in the presence of inadequate public health infrastructure.5 The growing demands for food availability, development and industrialization have resulted in encroachment on wildlife habitats and increased contact between humans and animals, resulting in a dynamic upward trajectory of these diseases.6,7 Many zoonotic diseases have significant impact on human health as well as livestock productivity, thereby undermining livelihoods both by causing illness in the household and threatening its livestock and their output.8
Variant influenza: connecting the missing dots
Published in Expert Review of Anti-infective Therapy, 2022
Vivek Chavda, Rajashri Bezbaruah, Tutumoni Kalita, Anupam Sarma, Juti Rani Devi, Ratnali Bania, Vasso Apostolopoulos
The World Health Organization (WHO) recognized zoonosis as any infection or illness that could spontaneously be transmitted either from non-human vertebrates to humans or from the human population to animal species [1-3]. The word ‘zoonoses’ was derived using the Greek words ‘zoon,’ which denotes animal, and ‘nosos,’ which implies disease. Approximately 61% of the human pathogens are zoonotic [4,5]. Since all living beings, including both animals and humans as well as the environment, contribute to the pathogenesis and prevalence of the disease, it was reported that a significant percentage of infectious diseases that impact people are caused by animals [6]. In recent decades, human diseases of animal origin have evolved, and these diseases have been linked to animal origin diets. Some diseases, such as HIV infection, start out as zoonosis, but later the strains mutate and affect only humans. Zoonoses are a notable health concern as well as a direct human health risk that can cause death [7]. Additionally, the 13 most frequent zoonoses have had the greatest impact on poor livestock workers in economically developing countries, causing an estimated 2.4 billion infected cases of the disease and 2.7 million human deaths per year [8]. The majority of these diseases have a negative influence on animal health and reduce animal productivity considerably [4].
Modern vaccine strategies for emerging zoonotic viruses
Published in Expert Review of Vaccines, 2022
Atif Ahmed, Muhammad Safdar, Samran Sardar, Sahar Yousaf, Fiza Farooq, Ali Raza, Muhammad Shahid, Kausar Malik, Samia Afzal
The emergence of novel pathogens from the animal reservoir with enhanced capacity for dissemination is another potential threat to public health [1]. The occurrence of infectious diseases through zoonosis has significantly increased in number and severity over the last two decades [2]. Zoonotic pathogens are responsible for 65% of emerging infectious diseases in humans and are mostly related to viruses [3]. The cryptic transmission of zoonotic intracellular parasites is a unique property that promotes successful dissemination in the susceptible population until its proper diagnosis. These are mostly respiratory diseases and primarily spread in the human population through breathing; however, few viral particles follow alternate pathways of transmission, but their transmissibility is low. These infections originate from the spillover of pathogens from animal reservoirs that exhibit several new characteristics along with few previous features. Therefore, zoonotic viruses either reemerge in the same geographical regions with mutated genotypes or emerge in different geographical territories with similar gene sets. The emerging and reemerging viral diseases in different geographical locations through distinct animal reservoirs with unique transmission patterns are discussed in Table 1. However, the unpredictable nature, elevated case fatality rates, uncertainty in the determination of responsible animal reservoir, and unidentified modes of transmission are distinguished features of zoonotic organisms making it a global threat to human health [4].