Environment

Antimicrobial Awareness Week 2021: Zoonoses as a driver for antimicrobial resistance

·         In recent years, the use, abuse and misuse of antimicrobials in both, the human and livestock sector, has resulted in large-scale antimicrobial resistance (AMR) among various pathogens and more so, in bacterial pathogens.

·         AMR occurs naturally over time, usually through genetic changes which is a part of natural evolution.

·         The resistant organisms are found in people, animals, foods, plants and the environment which can spread between and within the sectors.

·         AMR, particularly antibacterial resistance (ABR) is usually reportable at the interface of human, animal and atmosphere indicating the role of industry, farming, and veterinary practices in ABR additionally to human health practices.

·         Zoonosis A zoonosis is an infectious disease that has jumped from a non-human animal to humans.

·         Zoonotic pathogens could also be microorganism, viral or parasitic, or might involve unconventional agents and may unfold to humans through direct contact or through food, water or the atmosphere.

·         Zoonoses comprise a large percentage of all newly identified infectious diseases as well as many existing ones.

·         Researchers estimate 3/4ths of new, emerging diseases are zoonotic, with the vast majority coming from wildlife.

·         Some diseases, such as HIV, begin as a zoonosis but later mutate into human-only strains.

·         Other zoonoses can cause recurring disease outbreaks, such as Ebola virus disease and salmonellosis.

·         Still others, such as the novel coronavirus that causes COVID-19, have the potential to cause global pandemics.

·         Antimicrobial resistance is a complicating factor in the control and prevention of zoonoses.  

·         The use of antibiotics in animals raised for food is widespread and will increase the potential for drug-resistant strains of zoonotic pathogens capable of spreading quickly in animal and human populations.

·         World Zoonoses Day is celebrated on July sixth annually and commemorates the work of Louis Pasteur, who developed the first vaccinum.

·         59,000 people die each year from rabies, a leading zoonotic disease.

Classification of Zoonoses According to the etiological agents

·         Bacterial zoonoses :- e.g. anthrax, brucellosis, plague, zoonotic disease, salmonellosis, Lyme disease

·         Viral zoonoses :- e.g. rabies, arborvirus infections, KFD, yellow fever, influenza, CCHF

·         Rickettsialzoonoses :- e.g. murine typhus, tick typhus, scrub typhus,

·         Q-fever Protozoal zoonoses :- e.g. toxoplasmosis, trypanosomiasis, leishmaniasis

·         Helminthic zoonoses :- e.g. echinococcosis (hydatid disease), taeniasis, schistosomiasis, dracunculiasi.

 

·         Fungal zoonoses :- e.g. deep mycosis – histoplasmosis, cryptococcosis, superficial dermatophytes

·         Ectoparasites :- e.g. scabies, myiasis according to the mode of transmission

·         Direct zoonoses – These are transmitted from an infected vertebrate host to a vulnerable host (man) by direct contact, by contact with a physical object or by a mechanical vector.

·         The agent itself undergoes very little or no procreation or developmental changes throughout transmission, e.g. rabies, anthrax, brucellosis, zoonotic disease, toxoplasmosis.

·         Cyclozoonoses – These require more than one vertebrate host species, however no invertebrate host for the completion of the life cycle of the agent, e.g. echinococcosis, taeniasis

·         Meta zoonoses – These are transmitted biologically by invertebrate vectors, during which the agent multiplies and/or develops and theres continually an extrinsic  incubation (prepatent) amount before transmission to a different vertebrate host e.g., plague, arbovirus infections, schistosomiasis, leishmaniasis.

·         Saprozoonoses – These need a vertebrate host and a non-animal biological process site like soil, plant material, pigeon dropping etc. for the development of the infective agent e.g. aspergillosis, coccidiomycosis, cryptococosis, histoplasmosis, zygomycosis.