A zoonosis is an infectious disease transmitted to humans from non-human animals. Zoonotic pathogens can be bacteria, viruses or parasites, as well as non-traditional pathogens that can be transmitted to humans through direct contact or through food, water or the environment. Given our close ties to farmed, domestic and wild animals, zoonotic diseases represent a major health problem worldwide. They may also disrupt the production of animal products for human consumption and other uses and the trade in such products.
Zoonoses account for a significant proportion of all newly identified and many existing infectious diseases. Some diseases, such as HIV infection, begin as a zoonosis, but later strains mutate and only affect humans. Other zoonoses can cause periodic disease outbreaks, such as Ebola virus disease and salmonellosis. Others, such as the novel coronavirus that causes COVID-19, have the potential to lead to global pandemics.
Unpleasant surprises from nature
Many of us truly love animals. We perceive our pets as family members, often not really thinking about our own safety. But the idyll can be destroyed if minimal precautions are not taken. It is naive to believe that the tailed inhabitants of our apartments are one hundred percent protected from all kinds of diseases. They are by no means isolated from the environment. Even after an ordinary walk, they can bring some kind of “sore” into the house, which can cause a lot of trouble not only for the pet, but also for you and your household. And if you are going out of town, remember that only vaccinated animals can be taken out into the wild, otherwise, when faced with their wild counterparts, our pets can become a source of disease for us.
Speckled skin
Microsporia or ringworm is one of the most common skin diseases of animals. When people become infected from them, people also get sick: small spots appear on the skin, covered with gray scales; there can be from two to a hundred of them on the human body. The causative agent of microsporia also affects the hair, so sometimes during treatment the head has to be shaved, which is very unpleasant for the patient. If you notice even a slight redness in the shape of a circle or ring, do not be lazy - go to a dermatologist. If time is lost, curing the disease will be much more difficult.
Salvation is a vaccine
Of course, sanitary measures and personal hygiene play a huge role in the prevention of brucellosis. But this is not enough when there is a real threat of contact with a sick animal and infection. In such cases, vaccination is needed.
“For immunization against brucellosis caused by the most common type of Brucella - goat-sheep - live (attenuated) vaccines are used. They contain artificially weakened brucellae, which cannot provoke the disease, but cause an immune response. – explains Microgen expert Alexander Sergeev. – A person is vaccinated once: the solution is injected subcutaneously with a syringe or dripped onto the skin, scarifying it with a special instrument - a scarifier. If necessary, revaccination is carried out a year later - a smaller dose is used for it.”
The vaccine against brucellosis is produced at the branch of NPO Microgen in Omsk - the enterprise fully supplies the country with the drug. Although brucellosis is a rare disease, it is important for everyone to know about it, especially those who are at high risk of contracting the causative agent of this disease.
"Dogs can be biting..."
The main “reservoir” of the rabies virus is dogs, cats, wild animals, especially foxes. A sick animal behaves unusually: a domestic pet can become aggressive and refuse water and food, and vice versa, a wild animal is not afraid of people and comes out to them. To prevent rabies, pets must be vaccinated. Infection of a person occurs when a sick animal bites or its saliva gets on the mucous membranes and damaged skin, so if you are bitten by a dog or any other animal, the first thing you need to do is wash the wound with plenty of soap and water. There is no need to bandage or clamp the wound - the flowing blood will wash it away from the animal's saliva. But if a large blood vessel is bitten, this method is not applicable. And most importantly, if you are bitten by an animal, immediately consult a doctor at the emergency room at your place of residence! You can forget about the painful forty injections in the stomach - the new generation vaccines are injected into the shoulder and only six times. It should be remembered that rabies is a fatal disease, but timely vaccination actually prevents its development.
Three out of four
The main and most dangerous carriers of zoonoses, according to the international organization EcoHealth Alliance, are bats, primates and rodents. Pets can also be a source of infection, especially if they are not vaccinated. Transmission to humans occurs in the same ways as among animals: through the air, by eating the meat of infected individuals, through an insect bite.
The most dangerous infections of a zoonotic nature are considered to be the Zika and Ebola viruses, bird and swine flu, and others. Avian and swine influenza viruses arose through reassortment with human influenza virus strains and have caused pandemics in the past. The most notorious and deadly of them was the Spanish Flu of 1918-1920, which, according to various estimates, claimed from 50 to 100 million lives. The recent 2009 pandemic was also caused by gene exchange between human, swine and avian influenza virus strains. The current deadly coronavirus has been declared an international emergency by the WHO.
Scientists are unanimous in their opinion: outbreaks of new diseases not yet known to man will come to us in a similar way. Their causative agents will be viruses and bacteria that are initially found in animals. Unfortunately, epidemiological statistics leave no other options: three out of four new infections turn out to be zoonotic.
Bats are among the main carriers of zoonotic diseases / ©www.blackpantera.ru
The good news, however, is that today a significant number of zoonoses we know have been brought under control. Disease outbreaks that have caused deadly pandemics in the recent past have been stopped thanks to vaccination. Humanity has learned to fight back against germs by studying the principles of how the immune system works. Currently, there are scientific centers around the world to identify new infections in animals that may threaten human health. Programs are also being implemented to prepare for the prevention of possible outbreaks of diseases, where immunoprophylaxis plays a significant role.
Dangerous water
Leptospirosis is an acute infectious disease that affects both people and animals. Outbreaks of leptospirosis occur mainly in the summer. The main way leptospirosis spreads is through water. When traveling out of town, try to avoid staying near livestock farms or pastures. The cause of the disease can be the consumption of water from open sources, since animals that carry leptospirosis can introduce leptospira into the water along with saliva and urine. Small forest lakes and ponds with stagnant water, which are often natural foci of leptospirosis, are not suitable for washing and swimming. The causative agent of the disease can enter the human body through damaged skin and mucous membranes. The digestive tract can also be the “gate of entry” for infection. If, despite all precautions, you have chills, a sharp rise in temperature, headaches and muscle pain, or inflamed eyes, you should immediately consult a doctor.
Difficult to find and defeat
Brucellosis is considered a particularly dangerous infection, and that says it all. It is easy to become infected, treatment is long, there is a risk of serious complications, including those leading to disability, and in some cases death is possible. First, Brucella penetrates the lymph nodes, then spreads through the blood throughout the body and affects various organs. The immune system responds violently to the invasion of strangers, which is why brucellosis is considered an infectious-allergic disease. It usually takes 1–6 weeks (incubation period) before the first symptoms appear. The disease usually occurs in one of three forms: acute, subacute (recurrent) or chronic.
In the acute form, the temperature rises significantly - up to 39 degrees, chills, sweating occur, pain in muscles and bones occurs, general health worsens, and appetite disappears. With subacute brucellosis, periods of fever and deterioration of health alternate with periods of improvement. In chronic cases, the temperature is slightly elevated, the patient feels relatively well, and other symptoms depend on which organs are most affected.
The risk of getting sick is highest among rural residents / ©mtdata.ru
Moreover, the lesions are diverse and affect almost all human organ systems. With the advent of antibiotics, doctors began to fight brucellosis quite successfully, however, even today there is a possibility of fatal complications. If a person has been diagnosed with brucellosis, he will have to suffer for a long time. In the acute form, recovery will most likely be possible only after 2–6 months. Chronic disease can last for years; there are isolated cases where the disease could not be defeated for 25 years.
To effectively treat brucellosis, it must be diagnosed in time. And there are problems here. Due to nonspecific symptoms, not every doctor will immediately make the correct diagnosis. And people don’t always go to doctors, in the hope that “it will go away on its own.” As a result, not all cases of the disease are detected, and no one can say with absolute certainty how often it occurs: official statistics show underestimated figures. For Russia this is 400–500 cases per year. The diagnosis is confirmed by serological tests (test for bacterial antigens) and an allergic skin test.
Caution – toxoplasmosis!
Humans can be infected with toxoplasmosis by dogs, cats, rabbits, as well as ornamental, singing and farm birds. In animals, the pathogen is excreted in feces and urine, and mucus from the nose. People become infected mainly through contaminated foods. Once in the human body, the pathogen spreads through the bloodstream, affecting the brain, eyes, spleen, liver, and lymph nodes. Acute toxoplasmosis is usually accompanied by fever, headache and muscle pain. Chronic can last for years and is expressed in low-grade fever, irritability, decreased visual acuity, memory and performance. Prevention of the disease consists of identifying and treating sick animals, which must be periodically examined. The most important measure is washing hands after contact with animals, as well as heat treatment of meat and dairy products.
WHO activities
WHO works with national governments, academic institutions, nongovernmental and philanthropic organizations, and regional and international partners to prevent and respond to zoonotic disease threats and their health, social and economic impacts. These efforts include strengthening collaboration at the human-animal-environment interface between various relevant sectors at the regional, national and international levels. WHO also works to build capacity and promote evidence-based and cost-effective practical tools and mechanisms for the prevention, surveillance and detection of zoonotic diseases through reporting, epidemiological and laboratory research, risk assessment and control, and assist countries in their implementation.
As part of the One Health approach, the World Health Organization is collaborating with the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (OIE) to develop the Global Early Warning System for Major Animal Diseases (GEDS). This joint system builds on the added value of integrating and coordinating the alert mechanisms of the three agencies to facilitate early warning of, prevention and response to animal disease threats, including zoonoses, through data sharing and risk assessment.
Disease on bird rights
Indoor birds (budgies, canaries and other small songbirds) can be a source of infection with psittacosis (pneumochlamydia). People who usually have constant contact with birds get it. When infected at home, family outbreaks can occur. Infection occurs by airborne droplets - when particles of bird feces are inhaled with dust while cleaning cages. The disease usually occurs 5–10 days after an infected bird appears in the house. If your feathered pet has been living with you for several months, then most likely it is healthy and infection is unlikely (if during this time there has been no contact with other birds). A sick person develops chills, headache and muscle pain, an increase in body temperature to 38-40 degrees, a dry cough and sore throat. On the fifth to seventh day, chest pain, shortness of breath, cough with bloody mucous sputum, and signs of pneumonia appear. A person suffers from insomnia and dizziness. If you do not consult a doctor in time, subsequent relapses and the disease may become chronic. The danger of the disease should not be underestimated, therefore, when the first signs of illness appear, you should immediately see a doctor.
First, vaccinations...
If you notice any of the signs described above, do not rush to make a diagnosis yourself: even doctors never make a final verdict without the results of laboratory tests. It is better to immediately contact specialists, since it is always easier to get rid of any disease in the early stages. However, you need to be prepared for the fact that treatment can last from several weeks to months. In severe cases, hospitalization cannot be avoided. The best infection prevention is knowledge. Knowing that four-legged friends can be sources of very unpleasant diseases, it is wiser to prevent infection. If you pick up a dog or cat on the street, be sure to take it to the vet. He examines the animal for diseases, “illuminates” it with a fluorescent lamp to find out if there is microsporia, and gives the necessary vaccinations. Only then can you fearlessly introduce the foundling to your household. If the animal is sick, try to cure it; if the case is severe, it is better to euthanize - it will be more humane. But under no circumstances throw you out onto the street! After all, it becomes a source of infection for other people. And please practice good personal hygiene.
Who needs vaccination
“In Russia, measures to combat and prevent zoonoses are enshrined in law. In particular, immunization is carried out against tularemia, brucellosis, rabies, and Q fever. Such vaccinations are indicated for residents of areas recognized as disadvantaged by the epidemiological situation, specialists who, due to the nature of their work, face a high risk of infection, as well as those traveling to countries where there is a risk of infection,” says Doctor of Medical Sciences, Professor, Deputy Director of the Center for Development and Implementation NPO "Microgen" Alexander Sergeev.
Since zoonotic diseases most often affect residents of zones endemic for these diseases, large-scale vaccination of the population is not provided for within the framework of the National Preventive Vaccination Calendar. For this reason, not everyone knows about the need for prevention. Many people are either completely unaware of these infections or mistakenly believe that vaccinations are only given to animals. Meanwhile, technologies for the production of vaccines against many zoonotic infections were created by scientists back in the Soviet Union. Most of these drugs are today produced by NPO Microgen (part of the Nacimbio holding of the Rostec State Corporation).
“The company develops and produces original preventive drugs that have protected the health of citizens for more than a hundred years. Today we are a key player in the vaccine market and a center of competence in the creation of modern immunobiological drugs. Just last year we registered two new vaccines,” adds Alexander Sergeev.
