Symptoms of infection depend very much on the type of disease. General symptoms of infection include fatigue, loss of appetite, weight loss, fevers, night sweats, chills, aches, and pains.
The classic symptoms of a bacterial infection are local redness, fever, swelling, and pain at the site of infection. In general, viral infections are systemic, involving many different parts of the body at the same time; i. Antibacterial, antimycotic, and antiviral drugs have been developed that generally function by blocking bacteria, fungi, and viruses from replicating and surviving.
Penicillin as an antibacterial, for instance, functions by inhibiting synthesis of bacterial cell walls. Examples of penicillin drugs include amoxicillin and ampicillin. Bacteria constantly try to rebuild their peptidoglycan cell wall. Penicillin blocks the formation of peptidoglycan cross-links in the cell wall. As a consequence, transpeptidase cannot catalyze formation of these cross-links.
The imbalance between cell wall production and degradation causes the bacteria cells to rapidly die. Streptomycin or streptomycin sulfate is an antibacterial; it is a ribosome protein synthesis inhibitor. It binds to the small ribosomal RNA rRNA , 30S component of the bacterial ribosome causing codon misreading, eventual inhibition of protein synthesis and bacterial replication, and ultimately death of bacterial cells. Humans have structurally very different ribosomes from bacteria, thereby allowing the selectivity of this antibiotic for bacteria.
Tetracycline is an antibacterial that also functions by binding the small, 30S, bacterial ribosome, and blocking codon reading and bacterial replication.
A third type of antibacterial is fluoroquinolones. These include drugs such as Cipro and Levaquin. These are synthetic, bactericidal antibacterial agents with broad-spectrum activity. They inhibit the enzyme topoisomerase II, a DNA gyrase that is necessary for the replication of the microorganism. So antiviral drugs work differently to antibiotics, by interfering with the viral enzymes instead.
Antiviral drugs are currently only effective against a few viral diseases, such as influenza, herpes, hepatitis B and C and HIV — but research is ongoing. A naturally occurring protein, called interferon which the body produces to help fight viral infections , can now be produced in the laboratory and is used to treat hepatitis C infections.
It is possible to vaccinate against many serious viral infections such as measles, mumps, hepatitis A and hepatitis B. An aggressive worldwide vaccination campaign, headed by the World Health Organization WHO , managed to wipe out smallpox. However, some viruses — such as those that cause the common cold — are capable of mutating from one person to the next.
This is how an infection with essentially the same virus can keep dodging the immune system. Vaccination for these kinds of viruses is difficult, because the viruses have already changed their format by the time vaccines are developed. This page has been produced in consultation with and approved by:. Anthrax is a rare but potentially fatal bacterial disease that occasionally infects humans.
The Western obsession with cleanliness may be partly responsible for the increase in allergic asthma and conditions such as rhinitis. Careful prescribing of antibiotics will minimise the emergence of antibiotic resistant strains of bacteria. Aspergillus is a fungus that commonly grows on rotting vegetation. It can cause asthma symptoms. The simplest form of prevention for lyssavirus is to avoid close contact with bats. Content on this website is provided for information purposes only.
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The State of Victoria and the Department of Health shall not bear any liability for reliance by any user on the materials contained on this website. Skip to main content. Home Infections. They are typically studied with an electron microscope. Their mode of infection is different. Because of their distinct biochemistry, it should come as no surprise that bacteria and viruses differ in how they cause infection. Viruses infect a host cell and then multiply by the thousands, leaving the host cell and infecting other cells of the body.
A viral infection will therefore be systemic , spreading throughout the body. Pathogenic bacteria have a more varied operation and will often infect when the right opportunity arises, so called opportunistic infection.
The infection caused by pathogenic bacteria is usually confined to a part of the body, described as a localized infection. These infections may be caused by the bacteria themselves or by toxins endotoxins they produce. Examples of bacterial disease include pneumonia , tuberculosis , tetanus , and food poisoning. Viruses can infect bacteria.
Bacteria are not immune to viral hijackers which are known as bacteriophages —viruses that infect bacteria. Image by Venngage Infographic Maker.
Jameson JL, et al. Approach to the patient with an infectious disease. In: Harrison's Principles of Internal Medicine. New York, N. Clean hands count for safe health care. Centers for Disease Control and Prevention. Kumar P, et al. Infectious diseases and tropical medicine. In: Kumar and Clark's Clinical Medicine.
Philadelphia, Pa. LaRocque R, et al. Causes of infectious diarrhea and other foodborne illnesses in resource-rich settings. Ryan KJ, ed. Infectious diseases: Syndromes and etiologies. In: Sherris Medical Microbiology. File TM, et al. Epidemiology, pathogenesis, and microbiology of community-acquired pneumonia in adults. Accessed May DeClerq E, et al. Approved antiviral drugs over the past 50 years. Clinical Microbiology Reviews.
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