Zoonotic Diseases

Zoonoses are caused by different kinds of pathogens that can cause:

• Viral infections
• Bacterial infections
• Parasitic infections
• Fungal infections

Some of the common carriers of such pathogens are mosquitos, which are known to spread infections such as malaria, dengue fever and chikungunya.

There are several zoonotic diseases that have frequent outbreaks, as well as others that are rarer by comparison. However, such zoonotic diseases have made their presence felt all throughout human history. Some of the common zoonotic diseases are:

• Anthrax
• Bird flu (avian influenza)
• Capillariasis
• Chikungunya
• COVID-19
• Crimean-Congo hemorrhagic fever
• Dengue fever
• Ebola virus disease
• Hemorrhagic fevers such as Lassa fever, Marburg virus, etc.
• Hepatitis E
• Influenza A
• Japanese encephalitis
• Leprosy
• Lyme disease
• Malaria
• MERS (Middle-East respiratory syndrome)
• Nipah virus infection
• Plague
• Rabies
• Salmonella and E. Coli
• Swine Flu
• Tuberculosis
• West Nile Fever
• Zika fever

There are a few different ways that zoonoses infect and spread into a human population:

• Insect bites from mosquitos or ticks
• Eating contaminated meat or produce from infected animals
• Aerosol transmission, or through the air
• Through close contact with animals, such as in farms or poultry farms
• Touching an infected part of an animal, and catching the infection

The spread of diseases like swine flu and bird flu is said to have started through pig and poultry farms, where people came into contact with infected animals, who then passed the disease onto others through other modes of transmission.

Even families owning pets at home are at risk of contracting zoonotic disease through ticks and other insects.

Zoonotic diseases are caused by different pathogens—many of the symptoms are specific to the kind of pathogen that has infected the human body. As mentioned earlier, some diseases are more dangerous than others, and due precaution must be practised either while handling animals in a farm, zoo or similar environments, or at home, if you have pets.

Initial symptoms of zoonotic diseases, especially those caused by insect bites, can range from rashes on the skin, fever, headaches or dizziness, while in respiratory infections such as COVID-19, signs of breathing difficulty, chest pain, cough, fever, diarrhoea and several others can be seen in patients who may have come in contact with the pathogen either through an animal or by breathing in contaminated air.

Any of the above-mentioned signs developing should warrant a visit to the doctor to get it thoroughly investigated. Doctors usually take blood samples and perform other tests to arrive at the right diagnosis, and advise the next course of action.

Larger animal bites such as from dogs must be attended to immediately to avoid diseases such as rabies. Doctors usually give anti-rabies injections in such cases, or vaccines should be taken in advance to prevent such zoonotic diseases in the future as well.

Some individuals, however, are more at risk of contracting zoonotic diseases, either due to a weakened immune system, age (such as young children, people older than 60 years of age), life stage such as pregnancy, or those suffering from pre-existing conditions such as cancer, diabetes or HIV/AIDS.

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While emerging zoonotic diseases from unknown pathogens pose a serious risk to life for many people—COVID-19 has been a case in point—the risk posed by several zoonoses in the past have reduced due to the development of vaccines that can prevent such diseases from infecting an individual. Treatment options have also become available to cure patients of infections that may have claimed thousands of lives in the past.

Read more: Vaccine made out of mosquito spit out to stop next disease outbreak

The outbreak of mosquito-borne diseases such as malaria, dengue fever and chikungunya almost every year in various parts of India and other tropical regions means preventive measures must be followed to protect people and their families. The outbreak of other zoonoses caused by the practices of animal farming can also be avoided by enforcing the right safety regulations, which can prevent large numbers of people from getting infected.

Some daily practices that people can follow to prevent the onset of various zoonotic diseases are:

• Practising proper hand hygiene by washing hands with soap and water, or cleaning them with alcohol-based hand sanitizers when soap and water are not available.
• Using mosquito repellents in the form of ointments, sprays or patches in monsoon seasons. You could also use a mosquito net.
• De-infecting homes with sprays and getting indoor spaces cleaned through periodic pest control measures
• Buying fresh produce such as meats, animal products, fruits and vegetables, washing them properly before use and cooking them properly before consuming them. (Read more: How to wash fruits and vegetables during the COVID-19 pandemic)
• Be up to date on your pets' vaccinations and take them to the vet for their regular checkups.
• Look out for ticks in and around your house if you live with pets, and use the right sprays and pest control to keep your family safe.
• Avoid animal bites and frequent contact with animals other than your pets.
• Wear masks and gloves when working in an animal farm and handling sick animals, and avoid touching your face or any foods after handling them.
• Report to a doctor immediately in case an animal bites or scratches you—clean the wound properly.