Zoonoses, infectious diseases from animals that transmit to humans

The number of new diseases transmitted from animals also continues to increase every year. The coronavirus that causes the COVID-19 pandemic is one of the many viruses that are thought to have originated from wildlife, such as snakes and bats. Apart from coronavirus, what other types of zoonotic virus infections need to be watched out for?

Definition of zoonoses

Zoonoses are infectious diseases that are transmitted from animals to humans. Infection can be caused by disease-causing microorganisms (pathogens), such as bacteria, viruses, or parasites.

Pathogens originating from animals can move and develop in the human body after going through a series of genetic mutations. This allows these organisms to infect and cause infectious diseases among humans.

Environmental changes that are influenced by human activities, such as industrial plantations, deforestation, hunting, and animal husbandry, are getting closer to the interaction of wild animals with humans.

This could increase the potential for the spread of disease-causing organisms from animals to humans.

Some zoonotic disease transmission only occurs from animals to humans. However, the virus that causes HIV / AIDS, which was originally transmitted through chimpanzees, has now mutated into a virus that can spread directly between humans without an intermediate animal.

Zoonotic transmission

According to WHO, most of the zoonotic diseases that have emerged today are spread through direct contact with animals and consumption of meat, eggs and milk, fruits that contain pathogens.

Livestock and meat markets are the main entry points for zoonotic diseases from wildlife. In addition, dense and slum settlements are also at risk of spreading infectious diseases from rats and insects.

The following are ways of zoonotic transmission from animals to humans that you need to be aware of:

Animal bites that cause wounds on the skin.
Insect bites such as mosquitoes and fleas.
Eating meat of infected animals.
Inhale droplet (slime splash) containing pathogens.
Direct skin-to-skin contact with infected animals.
Making contact, either directly or indirectly, with feces or urine that contains disease-causing organisms.

On Encyclopedia of Microbiology explained that zoonoses can be transmitted directly from animals to humans, as can rabies.

Another possibility is that transmission could involve more than two intermediate animals, such as from tick bites that live on mice infected with the bacterium Borrelia, which causes Lyme disease.

Types of zoonoses

Infection with zoonotic-causing pathogens does not always cause disease in animals. This usually occurs in animals such as bats because they have strong immunity.

However, zoonoses often have harmful health effects on both animals and humans, such as rabies.

The types of zoonotic diseases also vary and can attack various organs and tissues of the body. The symptoms it shows can be acute and mild or the symptoms get worse slowly.

The types of zoonotic diseases that most commonly infect in Indonesia are:

1. Zoonoses transmitted from mosquito bites

Mosquito species in the tropics are intermediate insects that carry the microbes that cause dengue fever, chikungunya and malaria.

Mosquito Aedes aegypti and Aedes albopictus become an intermediary host for the dengue virus which causes dengue fever and the chikungunya virus.

A person infected with dengue fever and chikungunya can experience a high fever (more than 39 ℃) for days, blood pressure drops dramatically, and pain in strong joints.

Meanwhile, Anopheles mosquito bites carry parasites Plasmodium is a major cause of malaria. This zoonotic disease causes sufferers to experience a cycle of high fever for 6-24 hours accompanied by chills and sweating.

These three diseases need to be handled through intensive medical care in the hospital. In severe cases, this mosquito bite disease can cause blood clots and life-threatening shock.

2. Bird Flu

Bird flu was originally a viral infection disease that attacks poultry on farms. However, the virus then mutates and can infect other animals, such as pigs and dogs.

The genetic evolution of the virus eventually caused the H5N1 and H7N9 avian influenza viruses to spread among humans.

Even so, the spread of bird flu from one person to another is not as fast as the spread of influenza.

When infecting humans, this zoonotic disease can cause a flu disease that can develop rapidly causing serious respiratory problems. The fatality or death rate of bird flu occurs in 1 in 3 infected people.

3. Coronavirus

There are several types of coronavirus. The first is the SARS-CoV virus that causes SARS, MERS-CoV which causes MERS, and SARS-CoV-2 or Covid-19 which is now endemic.

Coronavirus infection attacks the respiratory tract, causing serious problems in the lungs. Symptoms include fever, cough and shortness of breath.

This zoonotic disease is thought to be transmitted by eating meat from wild animals. SARS-CoV 1 and 2 originate from bats and snakes, while MERS-CoV is spread due to contact and consumption of camel and bat meat.

4. Rabies

Rabies is a disease that most of the cases are transmitted through the bite of animals, such as dogs and bats.

When bitten, the virus infection that causes rabies, namely Rhabdovirus, does not immediately cause symptoms. However, when symptoms appear, they almost always have fatal consequences.

Rabies infection attacks the nervous system, causing sufferers to be more aggressive and hyperactive, easily agitated to disorders such as seizures, hallucinations, hyperventilation, and coma.

However, the dangers of this disease can be prevented through early treatment by injecting the rabies vaccine immediately after infection.

5. Salmonella infection

Salmonella is a bacterium that is the most common cause of diarrhea, also known as salmonellosis. This zoonotic disease most often occurs in poor hygienic environments.

You can catch these bacteria when you eat chicken eggs or food from contaminated milk. In addition, a common mode of transmission is through contact with infected pets.

The symptoms of diarrhea caused by salmonella infection are mild and can recover within a few days. However, without proper treatment, this zoonotic disease can cause severe dehydration, especially in children, the elderly, and people with weak immune systems.

6.Tinea infection (ringworm)

Tinea infection is a fungal infection disease that can be transmitted through pets, such as kittens and dogs. The fungi that cause this infection include Trichophyton, Microsporum, and Epidermophyton.

This zoonotic disease causes skin disorders in the form of a red, peeling rash. The fungus infects the outer part of the skin, namely the epidermis and resides in the dead keratin cells.

The rash mainly appears on the nails, chest, stomach, feet and hands. However, tinea infections can also affect the scalp, causing hair loss.

7. Toxoplasma infection

Toxoplasma infection or toxoplasmosis is a zoonotic disease caused by a parasite, named Toxoplasma gondii.

This parasite lives in the body of cats and is transmitted to humans through exposure to contaminated feces. Humans are usually infected with Toxoplasma when cleaning cat litter.

Infection can cause serious health problems for people with weakened immune systems and pregnant women. Toxoplasmosis is known as a disease that causes miscarriage, birth defects, or premature birth because it can infect the fetus.

Infectious diseases from other animals

There are still many pathogenic infections from animals that can cause health problems in humans, including:

Ebola comes from African bats
Anthrax is a bacterial infection that is transmitted from livestock
Bacterial infection E. coli
Hantavirus infection due to rat bite
HIV comes from chimpanzee bites
Lyme disease comes from the bite of a rat flea

How to prevent disease transmission from animals

Zoonotic diseases can spread through various transmission routes ranging from food, droplet (splash of saliva), air, or indirectly from insect bites.

Therefore, various efforts are needed to prevent the transmission of diseases originating from these animals. Some of the ways are:

Wash hands with soap and running water after contact with animals.
Use gloves when cleaning cages or animal waste.
Apply insect and insect repellent lotion to avoid mosquito bites.
Always wear footwear when in an animal farm environment.
Avoid drinking water that comes from rivers around animal farms.
Avoid drinking water from neighborhoods or settlements where zoonotic disease outbreaks occur.
Cook the meat until it is completely cooked.
Avoid close contact with wild animals.
Carry out rabies vaccination, including in pets.
Vaccinating for plague when traveling.

It would be better if this way of preventing infectious diseases became part of your daily habits. That way, the risk of infection to yourself and others can be minimized.

It is important for you to know the types of zoonotic diseases and their sources. Likewise with the way the disease is transmitted so that it can prevent and treat this disease appropriately.