Differences between viruses, bacteria and parasites

Although viruses, bacteria and parasites are capable of causing illness, the way they spread the disease to people is very different.

Virus - the cause of a cold from Ebola

According to Business Insider, the virus existed for a long time . The virus first appeared and may be the oldest ancestor of humans. The virus helps build the genome of all species, including humans. Our genome contains up to 50% of the DNA from retroviruses (the virus containing genetic material is the RNA molecule. In addition, the virus can pave the way for the formation of many DNA replication enzymes, which play an essential role in the distribution of DNA. cell division and development.

Microscopic image of rabies virus (Rabdoviridae).(Photo: Sanofi Pasteur / Flickr).

Viruses are capable of causing infectious diseases to humans and animals, some of which are even able to spread disease from animals to humans and vice versa. Virus life cycle has two stages. When they are outside the cell, they are called infertile virions . When they enter the cell, they take advantage of the cell's machinery to replicate. Some scientists believe that viruses exist in the organic form when in cells.

Some viruses, such as cold viruses, can make us sick but leave no long-term consequences. Meanwhile, many other viruses carry deadly pathogens. For example, a pandemic strain can spread quickly in a short time. Around the world, about 201,200 people die from acute respiratory and 83,300 other cardiovascular deaths in the 2009 H1N1 flu pandemic.

Although we are exposed to everyday viral molecules, we do not always become infected, since the immune system can handle most of these viruses. We are only sick when first exposed to a new virus or exposed to a large number of viruses. That's why health agencies always encourage flu vaccinations every year. Common strains of influenza can change each year, and immunity from previous infections or vaccines cannot protect us in case of contact with a modified strain.

The ability to spread and reproduce quickly makes some viruses become terrifying pathogens , to the extent that they are considered weapons of mass destruction. In addition, some viruses kill slowly, typically rabies virus with a long incubation period (1-3 months). Although the disease can be prevented with the vaccine, when symptoms appear, the patient almost certainly dies.

Vaccines are the best way to prevent viruses . The vaccine activates the immune response, allowing the body to respond more effectively when infected. The vaccine also reduces the risk of many potentially deadly viruses such as measles, rubella, flu and smallpox. In addition, washing your hands and covering your nose when sneezing are ways to limit viral spread.

Bacteria - intruders carry toxins

Some bacteria are beneficial to us , providing protection against pathogens and helping with intestinal digestion. However, some types are not benign. The common bacteria causing common diseases are staphylococcus aureus, poisoning (Clostridium botulinum), gonorrhea (Neisseria gonorrhoeae), gastric ulcer (Helicobacter pylori), diphtheria (Corynebacterium diphtheriae) and plague lymph nodes (Yersinia pestis).

Immunological identification of Helicobacter disease tissue.(Photo: KGH / Wikimedia Commons).

The bacterial toxin will invade cells or blood vessels, or compete with the host for nutrients, thereby leading to the risk of disease. The treatments must depend on how the bacteria causes disease. For example, in the case of poisoning, people get sick when eating contaminated food or C. botulinum spores. When the patient absorbs toxins, symptoms will appear within 6 - 36 hours. If spores are swallowed, these symptoms only appear after a week.

Supportive care is the main treatment to prevent or reduce complications and maintain patient health. Antibiotics treat infections by killing bacteria, but for poisoning, bacteria that are killed can secrete more toxins that make them worse. Doctors treat toxins by taking antitoxin or vomiting. Today, due to abuse and misuse of antibiotics, drug-resistant bacteria are increasing. In 2013, about 480,000 cases of drug-resistant tuberculosis (MDR-TB).

Using alternate antibiotics can reduce the risk of drug resistance. Currently, researchers are developing a number of other methods, such as using phage antimicrobial virus (a virus that kills bacteria) or enzymes capable of destroying the genome of drug-resistant bacteria. In fact, antibacterial viruses are widely used in Eastern Europe.

Bacterial vaccines such as diphtheria, pertussis and tetanus vaccines are in common use. In addition, many simple solutions can help prevent pathogenic bacteria such as proper hand washing , surface disinfection of tools, use of clean water and cooking with the right temperature to remove bacteria.

Parasites - parasites of our bodies

The parasite, the third group of pathogens, is a common name for many diverse organisms, living in or on the host's body and eating on that host , including humans. Parasites include single-celled organisms such as protozoa, or larger organisms such as worms or ticks. Single-celled parasites have more in common with human cells than bacteria. Parasites are everywhere, playing an important and complex role in the ecosystem.

A Aedes aegypti mosquito on a laboratory technician's arm studied how to prevent the spread of Zika virus and other mosquito-borne diseases in Guatemala on 4 February 2016.(Photo: Thomson / Reuters).

Parasites can also cause many diseases , especially in developing countries. In many cases, parasitic infections are often accompanied by poor sanitation and poverty. Malaria every 30 seconds kills children and 90% of cases are concentrated in Africa. This is the most deadly parasitic disease, although there are many advances in preventing this epidemic. Other common parasitic diseases include Leishmaniasis, filariasis and elephantiasis.

Many parasites are transmitted through mosquitoes and insects. With climate change becoming more severe, many parasitic diseases are spreading to the northern areas.

Currently, researchers have not found a vaccine to prevent human parasitic disease, but many drugs are now able to fight parasites. For example, the 2015 Nobel Prize in Medicine was awarded to scientists who have developed anti-parasitic drugs (Ivermectin for worms and Artemisinin for malaria treatment).