How are viruses different from bacteria and protists

As physicians, we evaluate to determine the best tests and treatments for each infection. Fayyaz Sutterwala , director of Infectious Diseases at Cedars-Sinai , says infections are sometimes difficult to diagnose.

Though certain microbes can cause very specific disease, many others can infect any organ and cause similar symptoms and immune response. A virus is the simplest of germs—it is nothing but genetic material encased in protein. Researchers debate whether a virus is even "alive.

By itself, a virus can accomplish nothing—it needs to enter a living thing to perform its only function, which is to replicate. When a virus gets inside a human body, it can hijack a person's cellular machinery to produce clones of itself, overtaking more cells and continuing to reproduce. When the virus reproduces faster than the immune system can control it, it begins to destroy cells and harm the body.

Viruses are also the smallest germ, making them generally the easiest to contract—they're so tiny they can spread through the air in a cough or a sneeze. Some viruses also are spread by mosquitoes or through bodily fluid. Since each virus is very different, no one drug exists to attack whichever virus is in your body.

Vaccines give preemptive protection from certain viruses by training the body's immune system to recognize and attack a specific virus. Common forms: Bacteria cause food poisoning, strep throat and urinary tract infections , as well as infections such as tuberculosis.

Spherical round bacteria include streptococcus, the cause of strep throat. Rod-shaped bacillus bacteria include anthrax and tetanus. Spiral bacteria have long bodies with a twist that form a spiral pattern when they are connected together; this group includes cholera. Bacteria reproduce most commonly by binary fission where a single parent bacterium divides to form two independent bacteria.

This type of reproduction is called asexual because there is no exchange or combination of nuclear material between two organisms. Fission occurs rapidly in as little as 20 minutes. Under perfect conditions a single bacterium could grow into over one billion bacteria in only 10 hours!

A large group of bacteria is called a colony, which you can often see without magnification. Different colonies can be identified by their shape, texture, and color. Some bacteria can also reproduce asexually by forming thick-walled endospores that are very resistant to conditions of extended heat, cold, or dryness.

An endospore is formed within the cell body of a bacterium. Usually a bacterium forms only one endospore and that endospore will produce only a single bacterium. Endospores are difficult to kill except by strong chemicals or high heat.

All the species in the Bacillus genus of bacteria produce endospores. Even the simple determination that a bacteria specimen is gram-positive or gram-negative can direct a doctor in diagnosis, as different bacteria cause different diseases. For example, the bacteria that causes scarlet fever is gram-positive, while that which causes typhoid or cholera is gram-negative. In addition, this classification process can help a doctor determine proper treatment, as some gram-negative bacteria are able to resist many common antibiotics.

So, how does it work? The stain will wash from a gram-negative cell because its cell wall contains more lipids fatty substances than a gram-positive cell. The washing solvent dissolves the lipid layer in gram-negative bacteria, allowing the color to be drawn from the cell. In contrast, the solvent causes the gram-positive cell wall to dehydrate, closing the pores and trapping the stain inside the cell.

Keywords: enterovirus; grazing; microbial inactivation; microbial virus control; predation; virus predation; water treatment; waterborne pathogen; waterborne viruses. Abstract Human viruses are ubiquitous contaminants in surface waters, where they can persist over extended periods of time. Publication types Research Support, Non-U. The primary difference between them is their cellular organization. Bacteria are single-celled microbes and are prokaryotes, which means they're single-celled organisms lacking specialized organelles.

In contrast, protists are mostly single-celled eukaryotic organisms that are not plants, fungi, or animals. About 70 percent of the time, symptoms of acute bacterial sinus infections go away within two weeks without antibiotics.

When sinusitis symptoms last seven to 10 days or more, it's a good idea to see a doctor to discuss treatment options. Acute bronchitis is normally caused by viruses , typically those that also cause colds and flu. It can also be caused by bacterial infection and exposure to substances that irritate the lungs, such as tobacco smoke, dust, fumes, vapors, and air pollution. They are similar to obligate intracellular parasites as they lack the means for self-reproduction outside a host cell, but unlike parasites, viruses are generally not considered to be true living organisms.

They are mainly broad-spectrum antibiotics that can be used for a wide variety of infections, such as respiratory tract infections, skin infections and urinary tract infections. Flucloxacillin is reserved for treating bacteria that are resistant to other penicillins. In some cases we become more concerned that the infection may be caused by a bacterial infection. Bacterial infections may be the result of "secondary infection" meaning that the virus initiated the process but a bacteria followed when the: Symptoms persist longer than the expected days a virus tends to last.

However, microbes that require other living cells to reproduce, called viruses , are acellular , meaning they contain no cells. Because of their prevalence, diversity, and importance to other organisms, viruses are considered alive by some scientists.

Pathogens are microorganisms - such as bacteria and viruses - that cause disease. Bacteria release toxins, and viruses damage our cells.