What Are Zoonotic Infections?
Animals and humans stay in close contact with each other and interact with them daily. Animals provide food, livelihood, fiber, and companionship to human beings. However, due to the interaction, these animals may pass on harmful germs to humans that cause disease. These diseases are known as zoonotic diseases or zoonoses. The causative organisms for zoonotic disease are viruses, bacteria, parasites, and fungi. The World Health Organization refers to zoonosis as any disease or infection naturally transmitted from a vertebrate animal to human beings or from human beings to animals. According to research, almost 61 % of animal pathogens are zoonotic in nature. The diseases caused by animals in humans can range from mild to severe and even lead to death. Usually, the animals appear healthy while they are infected and carrying germs.
What Is the Pathogenesis of Zoonosis?
Pathogenesis is the entry, replication, spread, and infestation establishment in the organs. Replication of the pathogens depends on cell-specific and organ-specific receptors, immunity of the hosts, tissue injury, and the body's defense mechanism. After entering the host, the pathogens either die and the infection stops or enter latency and incubation periods and remain dormant and inactive. The host may also transmit these pathogens to other hosts. Zoonotic agents and diseases are rarely transmitted sexually.
How Do Zoonotic Infections Spread?
Since animals and humans live in close contact, it is vital to know how humans can get infected with the pathogens that cause zoonotic infections. The various modes of zoonotic disease spread are:
- Direct Contact - When humans come in contact with saliva, blood, urine, mucosa, feces, or other body fluids, it's called direct contact. Alternatively, it can be passed through touching or petting the animals or through scratches or bites from the animals.
- Indirect Contact - Indirect contact occurs when humans come in contact with the surfaces infected by the animal or live within the areas where the animals either reside or roam. Examples of indirect contact are food and water containers of the pets, pet habitats, and chicken coops.
- Vector-Borne - It occurs when an insect, tick, or mosquito bites a person.
- Food-Borne - Eating contaminated and spoiled food is the main source of infection. Unpasteurized milk should be avoided as it is a leading source of infection. Undercooked meat and eggs should also be avoided for the same reason. Raw fruits and vegetables should always be washed and eaten as they may be contaminated with animal feces.
- Waterborne - Waterborne infections occur when the drinking or potable water has been polluted with the feces of an infected animal.
What Measures Can Be Taken at Home to Prevent the Spread of Zoonotic Infections?
Human contact with animals is an inevitable situation. We come in contact with animals and insects in our daily lives. Following certain preventive measures at home can prevent zoonotic infections from spreading.
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Hands should be washed properly with soap and water after touching or even being around animals. This prevents germs from spreading.
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If soap and water are unavailable, alcohol-based sanitizers should be used to clean the hands. This emergency aid should only be used when soap and water are unavailable, as cleaning with sanitizers does not eliminate all types of germs.
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Mosquito bites should be avoided by taking proper measures like using mosquito nets, using repellants, and wearing full-sleeve clothes.
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Houses should be regularly checked for mites and tick infestations.
How Can Zoonosis Be Prevented?
Zoonosis is a serious health threat and, if not controlled, can lead to a global epidemic. Zoonosis is the interlinkage between people, animals, and the environment and hence needs a multi-sectoral approach for effective disease control. Tight scrutiny and monitoring are needed to prevent and control the spread of zoonotic disease. Monitoring helps in the early detection of the infection, the affected animals and humans, vectors, endemic areas (areas where the disease is localized upon its outbreak), and hotspots (the area threatened with destruction due to infection). It helps formulate plans to control emerging and re-emerging diseases with the least effect on human health. It helps to lessen the cases of morbidity and mortality in humans and animals. Zoonotic infections spread rapidly and impact globally. Hence, local, regional, and international surveillance is needed for its control. Surveillance centers should be adequately equipped with labs and other diagnostic facilities.
The different types of surveillance or monitoring for controlling zoonoses and pathogen spread are:
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Pathogenic Surveillance: It helps detect pathogens like bacteria, fungi, parasites, and viruses.
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Serological Surveillance: It helps detect pathogens in the blood and saliva of humans and animals by monitoring their immune responses.
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Syndrome Surveillance: It helps to determine the disease tendency based on symptoms. However, it does not help in the detection of pathogens.
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Risk Surveillance: It helps detect risk factors that cause disease transmission; however, it does not identify the clinical features of the disease.
Zoonotic infections can be prevented by providing correct treatment, vaccination, stopping animal movement from one region to another, and conducting tests. In addition, infected materials should be disinfected and decontaminated to reduce the risk of transmission and acquiring new diseases.
Personal hygiene should also be maintained to avoid the risk of getting infected. Epidemiological surveillance is required to prevent vector-borne disease transmissions like dengue and malaria. It includes studying vector biology, its virulence, distribution, and socioeconomic status of the area. Mass pest and vector control should be undertaken to regulate the spread of a few bacterial and parasitic zoonotic infections.
Conclusion
The majority of zoonotic infections are a threat to public health but can be prevented. Young children, older people, pregnant women, and people with weak immune systems are more prone to infections. Veterinary doctors, medical doctors, public health workers, and environmental officers must be involved in planning to prevent and control zoonotic infections. Laws and regulations should be incorporated and implemented for proper isolation and quarantine. An effective and impactful disease-reporting system should be in place for public reporting. Mass media and social networking help in the spread of public awareness. Mass vaccination drives and public awareness are important in preventing zoonotic infections.
