| Adenovirus infection | |
|---|---|
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| Specialty | Infectious diseases[1] |
| Symptoms | Cough,runny nose,sore throat,pink eye,abdominal pain,muscle ache,fever,diarrhea,vomiting,fatigue |
| Complications | Adenoviral keratoconjunctivitis,pneumonia,acute respiratory distress syndrome,bronchiolitis,acute bronchitis,meningoencephalitis,myocarditis,cardiomyopathy,pericarditis,hepatitis,nephritis[2] |
| Usual onset | 2–14 days after exposure |
| Causes | Adenoviruses[3] |
| Risk factors | Endemic,hematopoietic stem cell transplantation[4] |
| Diagnostic method | Signs and symptoms,PCR test[5] |
| Differential diagnosis | Whooping cough,influenza,parainfluenza,respiratory syncytial virus[6] |
| Prevention | Hand washing,social distancing, avoid touching eyes, nose, and mouth[7] |
| Treatment | Symptomatic and supportive[7] |
| Prognosis | Usually recover without treatment[7] |
| Frequency | Common, all ages,[8] typically children under 5 years[2] |
Adenovirus infection is a contagiousviral disease, caused byadenoviruses, commonly resulting in arespiratory tract infection.[1][9] Typical symptoms range from those of acommon cold, such asnasal congestion,rhinitis, andcough, todifficulty breathing as inpneumonia.[9] Other general symptoms includefever,fatigue,muscle aches,headache,abdominal pain andswollen neck glands.[6] Onset is usually two to fourteen daysafter exposure to the virus.[10] A mildeye infection may occur on its own, combined with asore throat and fever, or as a more severeadenoviral keratoconjunctivitis with a painfulred eye,intolerance to light and discharge.[2] Very young children may just have anearache.[6] Adenovirus infection can present as agastroenteritis withvomiting,diarrhea, and abdominal pain, with or without respiratory symptoms.[2] However, some people have no symptoms.[5]
Adenovirus infection in humans are generally caused byAdenoviruses types B, C, E and F.[11]Spread occurs mainly when an infected person is in close contact with another person.[3] This may occur by eitherfecal–oral route,airborne transmission orsmall droplets containing the virus.[3] Less commonly, the virus may spread viacontaminated surfaces.[3] Other respiratory complications includeacute bronchitis,bronchiolitis andacute respiratory distress syndrome.[2] It may causemyocarditis,meningoencephalitis orhepatitis in people withweak immune systems.[2]
Diagnosis is by signs and symptoms, and a laboratory test is not usually required.[5] In some circumstances, aPCR test on blood or respiratory secretions may detect adenovirus DNA.[5][4] Other conditions that appear similar includewhooping cough,influenza,parainfluenza, andrespiratory syncytial virus.[6] Adenovirus gastroenteritis appears similar to diarrhoeal diseases caused by other infections.[12] Infection by adenovirus may be prevented bywashing hands, avoiding touching own eyes, mouth and nose with unwashed hands, andavoiding being near sick people.[7]A live vaccine to protect against types 4 and 7 adenoviruses has been used successfully in some military personnel.[7] Management is generallysymptomatic andsupportive.[7] Most adenovirus infections get better without any treatment.[7] Medicines to ease pain and reduce fever can be bought over the counter.[7]
Adenovirus infections affect all ages.[8] They occur sporadically throughout the year, and outbreaks can occur particularly in winter and spring, when they may spread more quickly in closed populations such as in hospitals, nurseries, long-term care facilities, schools, and swimming pools.[10] Severe disease is rare in people who are otherwise healthy.[10] Adenovirus infection accounts for up to 10% of respiratory infections in children.[10] Most cases are mild and by the age of 10-years, most children have had at least one adenovirus infection.[2] 75% of conjunctivitis cases are due to adenovirus infection.[13] In 2016, theGlobal Burden of Disease Study estimated that globally, around 75 million episodes of diarrhea among children under the age of five-years, were attributable to adenovirus infection.[12] The first adenoviral strains were isolated in 1953 by Rowe et al.[14]
Symptoms are variable, ranging from mild symptoms to severe illness.[2] They depend on the type of adenovirus, where it enters into the body, and on the age and well-being of the person.[6] Recognised patterns of clinical features include respiratory, eye, gastrointestinal, genitourinary and central nervous system.[6] There is also a widespread type that occurs in immunocompromised people.[6] Typical symptoms are of a mildcold or resembling theflu;fever,nasal congestion,coryza,cough, andpinky-red eyes.[15] Infants may also have symptoms of anear infection.[6] Onset is usually two to fourteen daysafter exposure to the virus.[10] There may betiredness,chills,muscle aches, orheadache.[6] However, some people have no symptoms.[5] Generally, a day or two after developing asore throat with large tonsils,glands can be felt in the neck.[16] Illness is more likely to be severe in people withweakened immune systems, particularly children who have had ahematopoietic stem cell transplantation.[4] Sometimes there is a skin rash.[2]
Preschool children with adenovirus colds tend to present with anasal congestion, runny nose and abdominal pain.[2] There may be a harsh barking cough.[2] It is frequently associated with a fever and a sore throat.[2] Up to one in five infants withbronchiolitis will have adenovirus infection, which can be severe.[2]Bronchiolitis obliterans is uncommon, but can occur if adenovirus causes pneumonia with prolonged fever, and can result indifficulty breathing.[2] It presents with a hyperinflated chest, expiratory wheeze and low oxygen.[2] Severe pneumonia is most common in very young children age three to 18 months and presents with sudden illness, ongoing cough, high fever, shortness of breath and afast rate of breathing.[2] There are frequentlywheezes andcrackles onbreathing in andout.[2]
Adenoviruseye infection may present as a pinkish-red eye.[2] Six to nine days following exposure to adenovirus, one or both eyes, typically in children, may be affected in association with fever,pharyngitis andlymphadenopathy (pharyngoconjunctival fever (PCF)).[6] The onset is usually sudden, and there is oftenrhinitis.[2] Adenovirus infection can also causeadenoviral keratoconjunctivitis.[2] Typically one eye is affected after an incubation period of up to a week.[2] The eye becomes itchy, painful, burning and reddish andlymphadenopathy may be felt by the ear nearest the affected eye.[2] The symptoms may last around 10 days to three weeks.[2] It may be is associated withblurred vision,photophobia and swelling of theconjunctiva.[2][13] A sore throat and nasal congestion may or may not be present.[2] This tends to occur in epidemics, affecting predominantly adults.[2] In very young children, it may be associated with high fever, sore throat,otitis media, diarrhoea, and vomiting.[2]
Adenovirus infection can cause agastroenteritis when it may present withdiarrhea,vomiting, and abdominal pain, with or without respiratory or general symptoms.[2] Children under the age of one-year appear particularly vulnerable.[12] However, it usually resolves within three-days.[2] It appears similar to diarrhoea diseases caused by other infections.[12]
Uncommonly the bladder may be affected, presenting with a sudden onset ofburning on passing urine and increased frequency of passing urine, followed by seeingblood in the urine a day or two later.[2]Meningism may occur in adenovirus associatedmeningoencephalitis, which may occur in people with weakened immune systems such as withAIDS orlymphoma.[2] Adenovirus infection may result in symptoms ofmyocarditis,dilated cardiomyopathy, andpericarditis.[2] Other signs and symptoms depend on other complications such asdark urine,itching andjaundice inhepatitis, generally in people who have aweakened immune system.[2] Adenovirus is a rare cause ofurethritis in men, when it may present with burning on passing urine associated with red eyes and feeling unwell.[17]
Adenovirus infection in humans are generally caused byAdenoviruses types B, C, E and F.[11]
Althoughepidemiologic characteristics of the adenoviruses vary by type, all are transmitted by direct contact,fecal-oral transmission, and occasionallywaterborne transmission. Some types are capable of establishing persistent asymptomatic infections in tonsils,adenoids, and intestines of infected hosts, and shedding can occur for months or years. Some adenoviruses (e.g., serotypes 1, 2, 5, and 6) have been shown to be endemic in parts of the world where they have been studied, and infection is usually acquired during childhood. Other types cause sporadic infection and occasional outbreaks; for example, epidemickeratoconjunctivitis is associated with adenovirus serotypes 8, 19, and 37. Epidemics of febrile disease with conjunctivitis are associated with waterborne transmission of some adenovirus types, often centering on inadequately chlorinated swimming pools and small lakes. ARD is most often associated with adenovirus types 4 and 7 in the United States. Enteric adenoviruses 40 and41 cause gastroenteritis, usually in children. For some adenovirus serotypes, the clinical spectrum of disease associated with infection varies depending on the site of infection; for example, infection with adenovirus 7 acquired by inhalation is associated with severe lower respiratory tract disease, whereas oral transmission of the virus typically causes no or mild disease. Outbreaks of adenovirus-associated respiratory disease have been more common in the late winter, spring, and early summer; however, adenovirus infections can occur throughout the year.[18]
Several adenoviruses, including Ad5, Ad9, Ad31, Ad36, Ad37, and SMAM1, have at least some evidence of causation ofobesity in animals, adipogenesis in cells, or association with human obesity.[19]
Diagnosis is by signs and symptoms, and a laboratory test is not usually required.[5] In some circumstances such as severe disease, when a diagnosis needs to be confirmed, aPCR test on blood or respiratory secretions may detect adenovirus DNA.[5][4] Adenovirus can be isolated by growing in cell cultures in a laboratory.[8] Other conditions that appear similar includewhooping cough,influenza,parainfluenza, andrespiratory syncytial virus (RSV).[6] Since adenovirus can be excreted for prolonged periods, the presence of virus does not necessarily mean it is associated with disease.[20]
Infection by adenovirus may be prevented bywashing hands, avoiding touching own eyes, mouth and nose before washing hands andavoiding being near sick people.[7] Strict attention to good infection-control practices is effective for stopping transmission in hospitals of adenovirus-associated disease, such as epidemic keratoconjunctivitis.[18] Maintaining adequate levels of chlorination is necessary for preventing swimming pool-associated outbreaks of adenovirus conjunctivitis.[7]A live adenovirus vaccine to protect against types 4 and 7 adenoviruses has been used in some military personnel.[7] Rates of adenovirus disease fell among military recruits following the introduction a live oral vaccine against types 4 and 7.[6] Stocks of the vaccine ran out in 1999 and rates of disease increased until 2011 when the vaccine was re-introduced.[6]
Treatment is generallysymptomatic andsupportive.[7] Medicines to ease pain and reduce fever can be bought over the counter.[7] For adenoviral conjunctivitis, a cold compress and lubricants may provide some relief of discomfort.[16]Steroid eye drops may be required if thecornea is involved.[16] Most adenovirus infections get better without any treatment.[7]
After recovery from adenovirus infection, the virus can be carried for weeks or months.[10]
Adenovirus can cause severe necrotizingpneumonia in which all or part of a lung hasincreased translucency radiographically, which is calledSwyer-James Syndrome.[21] Severe adenovirus pneumonia also may result inbronchiolitis obliterans, a subacute inflammatory process in which thesmall airways are replaced byscar tissue, resulting in a reduction inlung volume andlung compliance.[21]
Adenovirus infections occur sporadically throughout the year, and outbreaks can occur particularly in winter and spring.[10] Epidemics may spread more quickly in closed populations such as in hospitals, nurseries, long-term care facilities, boarding schools, orphanages and swimming pools.[10] Severe disease is rare in people who are usually healthy.[10] Around 10% of respiratory infections in children are caused by adenoviruses.[10] Most are mild and by the age of 10-years, most children have had at least one adenovirus infection.[2]
Adenoviruses are the most common viruses causing aninflamed throat.[16] 75% of conjunctivitis cases are due to adenovirus infection.[13] Under two-year olds are particularly susceptible to adenovirus gastroenteritis by types 40 and41, with type 41 being more common than type 40.[12] Some large studies have revealed type 40/41 adenovirus as one of the second most common causes of diarrhea in children inlow and middle income countries; the most common beingrotavirus.[12] In 2016, theGlobal Burden of Disease Study estimated that globally, around 75 million episodes of diarrhea among children under the age of five-years, were attributable to adenovirus infection, with a mortality of near 12%.[12]
Research in adenovirus infection has generally been limited relative to other respiratory disease viruses.[12] The impact of type-40/41 adenovirus diarrhoea is possibly underestimated.[12]
The first adenoviral strains were isolated fromadenoids in 1953 by Rowe et al.[14] Later, during studies onrotavirus diarrhoea, the wider use ofelectron microscopy resulted in detecting previously unrecognized adenoviruses types 40 and 41, subsequently found to be important in causing gastrointestinal illness in children.[2]
The illness made headlines in Texas in September 2007, when a so-called "boot camp flu" sickened hundreds atLackland Air Force Base in San Antonio.[22] In 2018, outbreaks occurred in an adult nursing home in New Jersey, and a college campus in Maryland.[8] In 2020, as a result of infection control measures during theCOVID-19 pandemic, rates of adenovirus diarrhoea declined significantly in China.[23]
Dogs can be affected by adenovirus infection.[24]Severe liver damage is a classical infectious disease seen in unvaccinated dogs.[25]
This article incorporatespublic domain material fromRespiratory and Enteric Viruses Branch.Centers for Disease Control and Prevention. Archived fromthe original on July 3, 2007. Retrieved2007-07-03.