Coinfection
Encyclopedia
In parasitology
, coinfection is the term used to describe the simultaneous infection
of a host
by multiple pathogen species
. In virology
, coinfection can also refer to the simultaneous infection of a single cell
by two or more virus
particles. An example is the coinfection of liver
cells with Hepatitis B virus
and Hepatitis D virus, which can arise incrementally by initial infection followed by superinfection
.
Global prevalence
figures for coinfections among human hosts are not available, but coinfection is thought to be commonplace, sometimes more common than single infection. Coinfections involving helminths affect around 800 million people worldwide.
Coinfection is of particular human health importance because pathogen species can interact
within the host. The net effect of coinfection on human health is thought to be negative. Interactions can have either positive
or negative effects on each of the coinfecting parasite species. Under positive parasite interactions, disease transmission
and progression are enhanced and this is also known as syndemism
. Negative parasite interactions include microbial interference when one bacterial species suppresses the virulence
or colonisation
of other bacteria, such as Pseudomonas aeruginosa
suppressing pathogenic Staphylococcus aureus
colony
formation. However, the general patterns of ecological interactions being parasite species are unknown, even among common coinfections such as those between sexually transmitted infections
.
A globally common coinfection involves both tuberculosis
and HIV
. In some countries, up to 80% of tuberculosis patients are also HIV-positive. The potential for dynamics of these two infectious diseases to be interlinked has been known for decades. Other common examples of coinfections are AIDS
or polymicrobial infections like Lyme Disease
.
Examples:
Parasitology
Parasitology is the study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question, but by their way of life...
, coinfection is the term used to describe the simultaneous infection
Infection
An 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...
of a host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
by multiple pathogen species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. In virology
Virology
Virology is the study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit cells for virus reproduction, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy...
, coinfection can also refer to the simultaneous infection of a single cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
by two or more virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
particles. An example is the coinfection of liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
cells with Hepatitis B virus
Hepatitis B virus
Hepatitis B is an infectious illness caused by hepatitis B virus which infects the liver of hominoidea, including humans, and causes an inflammation called hepatitis. Originally known as "serum hepatitis", the disease has caused epidemics in parts of Asia and Africa, and it is endemic in China...
and Hepatitis D virus, which can arise incrementally by initial infection followed by superinfection
Superinfection
In virology, superinfection is the process by which a cell, that has previously been infected by one virus, gets coinfected with a different strain of the virus, or another virus at a later point in time. Viral superinfections of serious conditions can lead to resistant strains of the virus, which...
.
Global prevalence
Prevalence
In epidemiology, the prevalence of a health-related state in a statistical population is defined as the total number of cases of the risk factor in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population...
figures for coinfections among human hosts are not available, but coinfection is thought to be commonplace, sometimes more common than single infection. Coinfections involving helminths affect around 800 million people worldwide.
Coinfection is of particular human health importance because pathogen species can interact
Biological interaction
Biological interactions are the effects organisms in a community have on one another. In the natural world no organism exists in absolute isolation, and thus every organism must interact with the environment and other organisms...
within the host. The net effect of coinfection on human health is thought to be negative. Interactions can have either positive
Ecological facilitation
Facilitation describes species interactions that benefit at least one of the participants and cause harm to neither. Facilitations can be categorized as mutualisms, in which both species benefit, or commensalisms, in which one species benefits and the other is unaffected...
or negative effects on each of the coinfecting parasite species. Under positive parasite interactions, disease transmission
Transmission (medicine)
In medicine and biology, transmission is the passing of a communicable disease from an infected host individual or group to a conspecific individual or group, regardless of whether the other individual was previously infected...
and progression are enhanced and this is also known as syndemism
Syndemic
Syndemic refers to the aggregation of two or more diseases in a population in which there is some level of positive biological interaction that exacerbates the negative health effects of any or all of the diseases...
. Negative parasite interactions include microbial interference when one bacterial species suppresses the virulence
Virulence
Virulence is by MeSH definition the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its...
or colonisation
Colonisation (biology)
Colonisation is the process in biology by which a species spreads into new areas, regions, and continents. It is sometimes also referred to as immigration, but colonisation often refers to successful immigration with integration to a community, having resisted initial local extinction.One classic...
of other bacteria, such as Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas 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...
suppressing pathogenic Staphylococcus aureus
Staphylococcus aureus
Staphylococcus 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...
colony
Colony
In politics and history, a colony is a territory under the immediate political control of a state. For colonies in antiquity, city-states would often found their own colonies. Some colonies were historically countries, while others were territories without definite statehood from their inception....
formation. However, the general patterns of ecological interactions being parasite species are unknown, even among common coinfections such as those between sexually transmitted infections
Sexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...
.
A globally common coinfection involves both tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
and HIV
HIV
Human 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...
. In some countries, up to 80% of tuberculosis patients are also HIV-positive. The potential for dynamics of these two infectious diseases to be interlinked has been known for decades. Other common examples of coinfections are AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
or polymicrobial infections like Lyme Disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
.
See also
- SyndemicSyndemicSyndemic refers to the aggregation of two or more diseases in a population in which there is some level of positive biological interaction that exacerbates the negative health effects of any or all of the diseases...
- SuperinfectionSuperinfectionIn virology, superinfection is the process by which a cell, that has previously been infected by one virus, gets coinfected with a different strain of the virus, or another virus at a later point in time. Viral superinfections of serious conditions can lead to resistant strains of the virus, which...
- Infectious diseaseInfectious diseaseInfectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...
Examples:
- Hepatitis DHepatitis DHepatitis D, also referred to as hepatitis D virus and classified as Hepatitis delta virus, is a disease caused by a small circular enveloped RNA virus. It is one of five known hepatitis viruses: A, B, C, D, and E. HDV is considered to be a subviral satellite because it can propagate only in the...
- HCV-HIV coinfection
- Hookworm-malaria coinfection