What You Need To Know About Zoonosis

Zoonosis is the general name given to infections or diseases that are transmissible between animals and humans.

How careful have you been guarding your life just to stay healthy? Do you know you could be more careful? You probably may not have known that the length of your lifespan is at risk if you ignorantly/carelessly deal with animals (either wild, domesticated, or livestock) you often have contacts with (directly or indirectly)?

We are surrounded by various animals, and most times, a non-veterinary individual may be ignorant of numerous diseases that he/she is predisposed to contract form these animals. However, since we cannot do well without animals, we need to equip our consciousness to avoid as many as possible zoonotic diseases.

This article, therefore, aims at opening your eyes to some life-threatening zoonotic diseases;

Rabies

Rabies virus is the causative pathogen of this zoonotic disease, which is highly transmissible between animals and humans. It is known to be present in almost all countries and territories of all continents except Antarctica. According to some research studies, about 60,000 people die of rabies every year, mostly in Africa and Asia.

The rabies virus attacks domestic and wild animals and may spread to people through close contact with infected animals’ saliva either through bites or scratches. The typical route of rabies transmission to humans is the bite from rabid dogs.

Since rabies disease can be prevented through vaccines, safe and effective vaccines for human and veterinary use should be considered essential. The most effective way of preventing rabies in people is by fighting dogs’ rabies through vaccination.

Vaccination in humans is highly necessary for anyone at frequent and increased risk of exposure to the rabies virus either; due to their occupation or residence, and for travelers with high extensive outdoor exposure and for children living in or visiting rural endemic areas.

Most importantly, the proliferation of clinical rabies in humans may be prevented through the local treatment of wounds and a primary immunization even after exposure to the virus, an intervention called PEP (post-exposure prophylaxis). Most human deaths are due to the absence of this PEP, particularly in timid areas of endemic countries where human and animal vaccines [and immunoglobulin] are not readily available or easily accessible.

Anthrax

Anthrax is a zoonotic disease that could be transferred from animals to humans. It is caused by a spore-producing bacterium, Bacillus Anthracis. Reservoirs are herb-eating animals, and the residual spores of the bacterium can survive in an environment for several years. Anthrax disease is ever-present (endemic) in several regions of the Globe, as well as southern and eastern Europe.

Humans may contract the infection after exposure to spores, and symptoms appear one to seven days (up to 60 days) after inoculation. Clinical effects result in lung anthrax, skin anthrax (with 75% death rate), and gastrointestinal forms (which may progress to blood infection and death).

An administration of antibiotics is effective against human anthrax if given at an early stage. Control measures

• Appropriate disposal of dead animals (mainly through burning).
• Decontamination of the environment.
• Disinfection of contaminated materials.
• Workers must put on protective wears.

Vaccination of exposed animals and humans is highly recommended. Anthrax-related bioterrorist threats have been severally reported in Europe. The agent was not confirmed, but a preparedness and response program for biological and chemical agent attacks (BICHAT) was developed in 2002 by the European Commission.

Avian Influenza or Bird Flu

Human infections are mainly acquired through direct contact with infected animals (birds) or polluted environments. These viruses have not developed the ability of prolonged transmission among humans.

Avian, swine and other zoonotic influenza virus infections in humans may lead to diseases ranging from mild upper respiratory tract infection (fever & cough), early sputum production, and rapid increase to severe pneumonia, acute respiratory distress syndrome, sepsis with shock, and even death. Conjunctivitis, inflammation of the bowel (enteritis), encephalitis, and encephalopathy have also been reported to vary in degrees depending on subtype.

Brucellosis

Brucellosis is a strong bacterial infection that spreads from animals to people. Prominent abortion-causing brucella bacteria, Brucella abortus, affects mainly ruminant animals alongside swine (pigs). Any careless human (male or female) infected by the bacterial spores may remain sterile for life. People may get infected if they eat raw or unpasteurized dairy products (e.g., milk, cheese). Sometimes, the bacteria that cause brucellosis may spread through the air (airborne) or direct contact with infected animals. The infection can always be treated with antibiotics. However, treatment may take several weeks to months, and the infection may recur.

Brucellosis affects thousands of animals and people globally. Avoiding unprocessed dairy products and taking precautions when working with vulnerable animals or in a laboratory would go a long way in preventing brucellosis.

Symptoms

Symptoms of brucellosis may surface anytime from a few days to a few months after the infection’s inoculation. Signs and symptoms of brucellosis are similar to those of the bird flu and include Chills, Loss of appetite, fever, fatigue, joint weakness, muscle and back pain, and headache.

Brucellosis symptoms may seize for weeks or months and then return. Some people with chronic brucellosis may experience symptoms for up to a year, even after treatment. Long-term signs and symptoms of brucellosis may include fatigue, inflammation of the heart (endocarditis), recurrent high fevers, arthritis, and spondylitis (inflammatory arthritis affecting the spine and nearby joints).

Leprosy

Mycobacterium leprae can cause leprosy, a chronic disease described by lesions on the skin and nerve damage in humans. The condition is treatable if noticed early using multidrug therapy (MDT). However, if left untreated, the disease may permanently damage the skin, eyes, nerves, and limbs.

Leprosy has been discovered to be transmitted zoonotically though armadillos (the only shell-wearing mammal).

Zoonotic Influenza

Zoonotic influenza disease is caused by influenza viruses of animal origin; the pathogen can cross over to infect humans.

Although the viral pathogen affects a good number of animal species, it could lead to a severe pandemic if it acquires the capacity to spread sustainably from one person to another.

When animal influenza viruses infect their target animal host, they are named for that host, as in avian influenza viruses, equine influenza viruses, swine influenza viruses, etc. As such, the term “swine flu” refers to swine influenza viruses of pigs (swine).

Ebola

Ebola virus disease (EVD) or Ebola hemorrhagic fever is widely known to be an emerging zoonotic disease. Ebola virus disease is a remarkably contagious disease that may infect either human and/or non-human primates. It is transmissible to humans through contact with infected body excretions and fluids (blood, saliva, and urea), consumption of infected tissue, and also from an infected human. The causative agent is scientifically classified in the genus Ebolavirus of the Filoviridae family.

Tuberculosis

Mycobacterium Bovis is the leading pathogenic causal agent of bovine (cow family) tuberculosis that could also cause zoonotic tuberculosis in humans. The common ways of transmitting the agent to humans are airborne transmission, unpasteurized milk intake, direct contact with infected animals, or septic animal products. Usually, treatment is not yet established in animals, but vaccination is carried out in some countries as a preventive measure. Due to the deadly consequences of M. Bovis infection on human and animal health, it is pertinent to introduce accurate control measures to reduce the disease’s risk in human or animal populations. Ensure proper food hygiene practices, slaughter the affected animals, and separate the suspected animals, along with a strong association between medical professions and the veterinary, are all pivotal for controlling the disease.

Prevention of Zoonotic Disease

Some factors need to be considered while we embark on our prevention plans. The three general conditions include; your hygiene, health management of the animals, and the environmental maintenance.

Optimum Personal Hygiene

1. Wash your hands before and after animal handling.
2. Inform your doctor of your animal-related activities.
3. Do not eat or drink around animal housing areas.
4. Wear coveralls, laboratory coats, or farm-specific clothing when handling animals.
5. DO NOT approach any of the agricultural animal facilities should you be ill.  You are more vulnerable to other infective agents, and you may as well transmit pathogens to the animals!
6. Always put on gloves before handling sick animals or animals with lesions.
7. Put on a mask if you are allergic to animal hair or dander or if feed or bedding dust is present.
8. Endeavor to always wear gloves when cleaning the animal area.
9. Note the pattern of any illness and report illnesses to your supervisor.

Environmental Maintenance

1. Always keep animal housing areas well clean and organized.
2. Avoid urea and fecal build-up.
3. Feed animals with clean feed and ensure clean and dry bedding from floors.  Litter attracts vermin, which may invite a zoonotic disease into the facility.
4. Clean rooms have a lower likelihood of zoonotic transfer.
5. Proper ventilation protects the animal and workers around the environment.

Herd/Flock Maintenance

1. Observe animals and take note of their health conditions daily.
2. Report any sick or dead animals.
3. Take note of health problems such as diarrhea, dyspnea (difficulty in breathing), depressed, immobile.
4. Take adequate caution when cleaning the areas around ill animals and do not spread possible pathogens.
5. Isolate affected animals away from the herd.
6. Keep records of the history and symptoms of the diseases to aid further treatment.