Opportunistic infection
Encyclopedia
An opportunistic infection is an infection caused by pathogen
s, particularly opportunistic pathogens
—those that take advantage of certain situations—such as bacterial, viral, fungal or protozoan infections that usually do not cause disease in a healthy host, one with a healthy immune system. A compromised immune system
, however, presents an "opportunity" for the pathogen to infect.
can be caused by:
s.
and Feline immunodeficiency virus
retroviral infections can be treated with Lymphocyte T-Cell Immune Modulator
.
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s, particularly opportunistic pathogens
Opportunism
-General definition:Opportunism is the conscious policy and practice of taking selfish advantage of circumstances, with little regard for principles. Opportunist actions are expedient actions guided primarily by self-interested motives. The term can be applied to individuals, groups,...
—those that take advantage of certain situations—such as bacterial, viral, fungal or protozoan infections that usually do not cause disease in a healthy host, one with a healthy immune system. A compromised immune system
Immunodeficiency
Immunodeficiency is a state in which the immune system's ability to fight infectious disease is compromised or entirely absent. Immunodeficiency may also decrease cancer immunosurveillance. Most cases of immunodeficiency are acquired but some people are born with defects in their immune system,...
, however, presents an "opportunity" for the pathogen to infect.
Causes
Immunodeficiency or immunosuppressionImmunosuppression
Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
can be caused by:
- MalnutritionMalnutritionMalnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
- Recurrent infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s - Immunosuppressing agentsImmunosuppressive drugImmunosuppressive drugs or immunosuppressive agents are drugs that inhibit or prevent activity of the immune system. They are used in immunosuppressive therapy to:...
for organ transplantOrgan transplantOrgan transplantation is the moving of an organ from one body to another or from a donor site on the patient's own body, for the purpose of replacing the recipient's damaged or absent organ. The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be...
recipients - Advanced HIVHIVHuman immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
infection - ChemotherapyChemotherapyChemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
for cancerCancerCancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the... - GeneticGeneticsGenetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
predisposition - SkinSkin-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
damage - AntibioticAntibioticAn antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
treatment - Medical procedures
- Pregnancy
Types of infections
These infections include:- Acinetobacter baumanni
- AspergillusAspergillusAspergillus is a genus consisting of several hundred mold species found in various climates worldwide. Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli...
sp. - Candida albicansCandida albicansCandida albicans is a diploid fungus that grows both as yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections including those by C...
- Clostridium difficileClostridium difficileClostridium difficile , also known as "CDF/cdf", or "C...
- Cryptococcus neoformansCryptococcus neoformansCryptococcus neoformans is an encapsulated yeast that can live in both plants and animals. Its teleomorph is Filobasidiella neoformans, a filamentous fungus belonging to the class Tremellomycetes. It is often found in pigeon excrement....
- CryptosporidiumCryptosporidiumCryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhea in humans.Cryptosporidium is the organism most commonly isolated in HIV positive patients presenting with diarrhea...
- CytomegalovirusCytomegalovirusCytomegalovirus is a viral genus of the viral group known as Herpesviridae or herpesviruses. It is typically abbreviated as CMV: The species that infects humans is commonly known as human CMV or human herpesvirus-5 , and is the most studied of all cytomegaloviruses...
- Geomyces destructansGeomyces destructansGeomyces destructans is a psychrophilic fungus that is associated with White nose syndrome , a fatal disease that has decimated bat populations in parts of the US. Unlike other species of Geomyces, Geomyces destructans forms asymmetrically curved conidia...
- Histoplasma capsulatum
- Isospora belliIsospora belliIsospora belli is a species of internal parasites classified under Coccidia. It is responsible for the condition isosporiasis. Autofluorescence aids detection....
- Polyomavirus JC polyomavirusJC virusThe JC virus or John Cunningham virus is a type of human polyomavirus and is genetically similar to BK virus and SV40. It was discovered in 1971 and named using the two initials of a patient with progressive multifocal leukoencephalopathy...
, the virus that causes Progressive multifocal leukoencephalopathyProgressive multifocal leukoencephalopathyProgressive multifocal leukoencephalopathy , also known as progressive multifocal leukoencephalitis, is a rare and usually fatal viral disease that is characterized by progressive damage or inflammation of the white matter of the brain at multiple locations .It occurs almost exclusively in...
. - Kaposi's SarcomaKaposi's sarcomaKaposi's sarcoma is a tumor caused by Human herpesvirus 8 , also known as Kaposi's sarcoma-associated herpesvirus . It was originally described by Moritz Kaposi , a Hungarian dermatologist practicing at the University of Vienna in 1872. It became more widely known as one of the AIDS defining...
caused by Human herpesvirus 8 (HHV8), also called Kaposi's sarcoma-associated herpesvirus (KSHV) - Legionnaires' Disease (Legionella pneumophila)LegionellosisLegionellosis is a potentially fatal infectious disease caused by gram negative, aerobic bacteria belonging to the genus Legionella. Over 90% of legionellosis cases are caused by Legionella pneumophila, a ubiquitous aquatic organism that thrives in temperatures between , with an optimum temperature...
- Microsporidium
- Mycobacterium avium complex (MAC) (Nontuberculosis Mycobacterium)
- Pneumocystis jiroveciiPneumocystis pneumoniaPneumocystis pneumonia or pneumocystosis is a form of pneumonia, caused by the yeast-like fungus Pneumocystis jirovecii...
, previously known as Pneumocystis carinii f. hominisHominis-Biology:* Sarcoptes scabiei var. hominis, a mite subspecies-Religion:*Redemptor Hominis, the first encyclical written by Pope John Paul II... - Pseudomonas aeruginosaPseudomonas aeruginosaPseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many...
- Staphylococcus aureusStaphylococcus aureusStaphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
- Streptococcus pyogenesStreptococcus pyogenesStreptococcus pyogenes is a spherical, Gram-positive bacterium that is the cause of group A streptococcal infections. S. pyogenes displays streptococcal group A antigen on its cell wall. S...
- Toxoplasma gondiiToxoplasma gondiiToxoplasma gondii is a species of parasitic protozoa in the genus Toxoplasma. The definitive host of T. gondii is the cat, but the parasite can be carried by many warm-blooded animals . Toxoplasmosis, the disease of which T...
Treatment
Treatment depends on the type of opportunistic infection, but usually involves different antibioticAntibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s.
Veterinary treatment
Opportunistic infections caused by Feline Leukemia VirusFeline leukemia virus
Feline leukemia virus is a retrovirus that infects cats. FeLV can be transmitted between infected cats when the transfer of saliva or nasal secretions is involved. If not defeated by the animal’s immune system, the virus can be lethal...
and Feline immunodeficiency virus
Feline immunodeficiency virus
Feline immunodeficiency virus is a lentivirus that affects domesticated housecats worldwide and is the causative agent of feline AIDS. From 2.5% up to 4.4% of cats worldwide are infected with FIV...
retroviral infections can be treated with Lymphocyte T-Cell Immune Modulator
Lymphocyte T-Cell Immune Modulator
Lymphocyte T-Cell Immune Modulator is an immune regulating polypeptide manufactured by T-Cyte Therapeutics and distributed by . Lymphocyte T-Cell Immune Modulator is a potent regulator of CD-4 lymphocyte production and function. It has been shown to increase lymphocyte numbers and Interleukin-2 ...
.