Zoonosis: Causes, Symptoms & Treatment

Infections that can be transmitted from animals to humans are more common than thought. This problem is most common in Africa and India. However, there are also cases of disease called zoonosis in Europe.

What is a zoonosis?

Under the term zoonosis, all infectious diseases are summarized, in which a transmission between animals and humans occurs. Here, animals form the pathogen reservoir, while in most cases humans are the final link in this chain of infection. The most widespread zoonoses in Central Europe include salmonella enteritis, anthrax, brucellosis, leptospirosis, Q fever, yersiniosis and listeriosis. More than 200 zoonotic diseases are known worldwide. In particular, factory farming, which is common in technologically advanced countries, has promoted the spread of many zoonoses.

Causes

A zoonosis can be caused by viruses (avian influenza, rabies), bacteria (salmonellosis, Lyme disease), fungi (trichophytosis), protozoa (toxoplasmosis, leishmaniasis), or worms (diphyllobothriasis, dirofilariasis). The possible modes of transmission are diverse. For example, zoonosis can occur through direct contact with infected animals, through animal foods such as milk, meat, or eggs, and through pathogens known as vectors. These vectors do not cause or contract the disease themselves. A commonly known example of such vectors are, for example, ticks that transmit early summer meningoencephalitis (TBE). When the tick bites a human, the TBE viruses are transmitted to the human. However, the bite itself is not the cause of the disease. This is also the reason that not everyone who is bitten by a tick gets FMSE.

Symptoms, complaints, and signs

Zoonotic disease can affect anyone. Often, people with a previous illness are afflicted with severe symptoms. An illness can lead to life-threatening complications in them. Meningitis and others are possible. The signs are not clear depending on the manifestation. Mostly the skin is affected or there are symptoms reminiscent of flu. Skin redness is widespread. These occur alone or are associated with headache and fatigue. Nausea and diarrhea also present. The most common zoonosis is toxoplasmosis. It causes illness for several weeks before subsequent recovery without any medical help. It is characterized by febrile conditions and swollen lymph nodes. The internal organs are also sometimes attacked in zoonosis. If transmission via food occurs, the gastrointestinal tract is affected. Sick people complain of fever, abdominal pain and diarrhea. Many people are familiar with the infection via salmonella. It causes a classic intestinal disease. In some cases, such as Lyme disease, joint and limb pain also occur. In severe cases, there are problems with the heart, liver and spleen. Sometimes symptoms can be made out on the nervous system.

Diagnosis and course

A detailed discussion of the course of the disease to date is crucial to the diagnosis of zoonotic disease. This conversation is followed by a physical examination and possibly a blood test. The use of other diagnostic tools depends on the type of zoonosis suspected. Depending on the symptoms, blood cultures, stool samples, bone marrow, samples from abscesses, and lymph nodes, for example, are used to detect the pathogen responsible for the zoonosis.

Complications

The complications of zoonotic disease depend on the type of infection, the course of the disease, and other factors. Basically, viral diseases are associated with general symptoms such as fever, which can be life-threatening if not treated. For example, untreated avian influenza often leads to severe pneumonia, while rabies can cause meningitis. Zoonotic disease is almost always associated with skin redness and accompanying symptoms such as itching or bleeding. Blood poisoning can also occur in the course of disease transmission from animal to human. The exact symptoms depend on how severe the infection is and how quickly it is treated.Early treatment can usually prevent serious complications, but in the case of rabies or avian influenza, secondary symptoms and sometimes late effects are always to be expected. In zoonotic therapy, the risks come mainly from the prescribed drugs. Antibiotics occasionally cause headaches, muscle and joint pain, gastrointestinal complaints or skin irritations, and permanent damage to internal organs is also possible with prolonged use. With symptomatic treatment, complications depend on the particular drug prescribed.

When should you see a doctor?

In the event of a deterioration in general health, a doctor should always be consulted. In particular, people with pre-existing conditions or a weakened immune system should seek the support and assistance of medical care as soon as they perceive any impairment of their well-being. In particular, they should act as quickly as possible when changes occur. A diffuse feeling of illness, faintness or fatigue are already among the complaints that should be investigated. Nausea, vomiting or diarrhea are also cause for concern. Disturbances of sleep, increased body temperature and abdominal pain should be presented to a physician. If these irregularities persist for several days or increase in intensity and magnitude, a physician should be consulted immediately. Swelling of the lymph nodes, irregularities of the gastrointestinal tract, or disturbances of the heart rhythm require medical attention. In the event of a severe course of the disease, zoonosis may cause the premature death of the affected person. Therefore, high-risk patients in particular are encouraged to discuss changes in their health with a physician. If headaches, inner restlessness or joint pains become apparent, there is a need for action. Cognitive changes and behavioral abnormalities should also be presented to a physician. Lack of appetite or a loss of body weight are among the complaints for which medical care is necessary. Failure to do so may result in malnutrition of the organism and secondary diseases.

Treatment and therapy

The therapy of a zoonosis also depends on its type. In bacterial zoonoses, treatment is usually by administration of appropriate antibiotics. Usually, this is prescribed for several weeks, or even longer in the case of affected organs. As a rule, an effective antibiotic is determined by laboratory tests. In the case of most infections affecting the digestive tract, treatment is exclusively symptomatic by compensating for fluid and salt losses. In these cases, antibiotics are not appropriate, with some exceptions (meningitis, septicemia, permanent excretions, babies), because they shorten the course of the disease but prolong the excretion of germs.

Prevention

Because zoonotic disease can have many underlying causes, there are no generally applicable measures for prevention. Good hygiene is generally an important protection against infectious diseases of any form. Even regular and thorough hand washing with hot water and soap can prevent many infections. Hygienic storage and preparation of food are also important preventive measures. Heating or freezing food helps to prevent some zoonoses, such as tick-borne encephalitis or toxoplasmosis. However, prions, which cause the new form of Creutzfeldt-Jakob disease, for example, are very resistant and cannot be killed by such means. Some zoonotic pathogens can be tackled by disinfection. These include influenza viruses, for example. In most cases, infection with a zoonosis occurs via food. However, caution should also be exercised when a zoonosis is detected in a pet. In this case, it is best to clarify with the veterinarian in which form a transmission of the pathogen can occur and how long the animal is contagious. Thorough hand washing is essential after contact with a zoonotic infected animal. Cages, litter boxes, etc. must be cleaned daily when an animal is infected with a zoonotic disease. In general, when handling pets as well as farm animals, care must be taken to ensure that they are kept hygienically and in a manner appropriate to their species. Lice, ticks and mites should be removed as soon as possible and worm-prone animals should be dewormed regularly. In addition, some zoonotic infections can be prevented by appropriate vaccination. Many people become infected with a zoonosis while traveling.Therefore, it is advisable to obtain accurate information about the destination in advance and take appropriate protective measures in the form of vaccinations or emergency medication.

Aftercare

Depending on how severe the symptoms were, the body is very weakened by a zoonosis suffered through. Therefore, everything that helps the patient recover is recommended in aftercare. First and foremost, this includes a healthy lifestyle. Especially during the aftercare period, long walks in the fresh air and other physical activities are indicated. They get the patient’s circulation going, but without overtaxing it at the same time. Of course, the patient should also not put unnecessary strain on his immune system. Long disco evenings, smoking or excessive alcohol consumption are therefore not advisable. Instead, a regulated sleep and wake rhythm with fixed rest and rise times is recommended. A healthy diet is also part of aftercare. Eating food that is too fatty and too high in calories puts unnecessary strain on the body. Light, freshly cooked meals from organically grown foods are advised. The diet should contain many vitamins, minerals and fiber. In addition, two liters of water daily are recommended to relieve the patient’s liver and kidneys and flush out possible toxins. If the patient has taken an antibiotic to treat his zoonosis, this may have caused damage to the intestinal flora. Because a large proportion of human immune cells are located in the intestine, in this case administration of probiotics is therefore indicated. A naturopathic doctor or alternative practitioner can recommend appropriate products.

What you can do yourself

In any case, the treatment of a zoonosis belongs in medical hands. Depending on the type of zoonosis the patient is suffering from, the therapy may be long and difficult. Good compliance is now important: especially if antibiotics have been prescribed, it is essential that the patient adheres to the advised dose and duration of treatment. At the same time, the patient can also watch out for possible undesirable side effects of antibiotic therapy, such as fungal infections on the skin. The sooner they are detected, the sooner they can be treated and eliminated. Zoonosis and its treatment can be very debilitating to the body. Therefore, during the period of illness and convalescence, patients should take care to actively support the healing process by, on the one hand, not additionally burdening the body with toxins (alcohol, nicotine, exhaust fumes, drugs, etc.) and, on the other hand, allowing themselves sufficient rest periods. A healthy diet also has a positive influence on recovery. Plenty of exercise in the fresh air additionally activates the immune system. Future sources of infection for a zoonosis should be eliminated as far as possible. This includes the hygienic preparation of impeccable food as well as regular deworming of one’s own pets and protection against ticks outdoors. Especially when walking in the woods, long legwear and the use of a repellent to protect against ticks are advisable, especially in Germany’s TBE risk areas.