Cytomegalovirus pneumonia is an inflammation of the lung tissue caused by primary or secondary infection by the cytomegalovirus, which belongs to the Herpesviridae group of viruses. It mostly affects immunocompromised individuals.
Presentation
Cytomegalovirus (CMV) pneumonia can occur regardless of host immune status, however, the infection is latent in immunocompetent individuals. Reactivation of the virus is possible, and this leads to secondary infection.
In the context of a normally functioning immune system, infection is largely asymptomatic and full blown pneumonia is rare, even if infiltrates are visible radiologically. Fever, lymphadenopathy and flu-like symptoms, in what is termed CMV mononucleosis, with or without the presence of a cough, is the most frequently described clinical presentation. In the event that severe pneumonia is contracted, full recovery following initiation of antiviral treatment is typical.
In practice, most documented cases of cytomegalovirus pneumonia are confined to immunosuppressed individuals, and the disease is often severe and fatal. This includes those who have undergone chemotherapy, radiotherapy, long-term steroid therapy, organ and bone marrow transplant recipients and those suffering from acquired immunodeficiency syndrome (AIDS). The latter are at the highest risk when serum concentrations of T helper cells fall below 50 cells per cubic millimeter. Among those who receive organ transplants, the probability of CMV pneumonia differs; for instance those who receive cells or organs originating from another donor have up to a 30% risk, whereas those receiving their own harvested cells have a much lower risk (1%- 6%) [1]. Furthermore, bone marrow transplant recipients are the most susceptible to disease, with untreated case fatality rates of over 80%, and 15-75% with appropriate treatment [1]. Symptoms experienced include
Symptoms of CMV pneumonia include cough, fever, night sweats, respiratory distress, hypoxia, myalgia, arthralgia, and fatigue. Radiological evidence of disease can sometimes precede outward signs of infection. The infection may affect other organ systems simultaneously, thus provoking a wider symptom profile. As it is a life-threatening illness, immunosuppressed patients are habitually initiated on CMV prophylaxis [2] [3] [4].
Importantly, neonates can also suffer from cytomegalovirus pneumonia when they acquire the infection from infected mothers through the placenta, birth canal, or during and breastfeeding.
Entire Body System
- Fever
Fever and dyspnea were the most frequent symptoms. The most frequent radiological signs were bilateral pulmonary infiltrates. Six cases were complicated by hemophagocytic lymphohistiocytosis. [ncbi.nlm.nih.gov]
Gancyclovir resolved the pancytopenia, pneumonia, and fever. There have been only 3 reported cases of CMV-related HPS in collagen disease. [jstage.jst.go.jp]
Hypoxia, if extreme, may be fatal. cytomegalovirus pneumonia Pulmonology A viral pneumonia characterized by fever, non-productive cough, SOB and association with PCP, especially in AIDS; hypoxia, if extreme, may be fatal. [medical-dictionary.thefreedictionary.com]
- Malaise
Symptoms Cough Fatigue Fever General discomfort, uneasiness, or ill feeling (malaise) Loss of appetite Muscle aches or joint pains Shortness of breath Shortness of breath on exertion Sweating, excessive (night sweats) Low oxygen levels in the blood (hypoxemia [dxline.info]
In immunocompetent patients > 90%: asymptomatic course < 10% : CMV mononucleosis Fever, malaise, myalgia / arthralgia, fatigue, headache Less common: sore throat, cervical lymphadenopathy, hepatomegaly, splenomegaly Differential diagnosis: infectious [amboss.com]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) The goal of treatment is to use antiviral drugs to [medlineplus.gov]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) Exams and Tests The doctor or nurse will perform a [m.ufhealth.org]
[…] class I and II molecules, which helps it elude host immune responses Clinical features In immunocompetent patients, cough with interstitial infiltrates on chest xray Immunosuppressed patients present with cough, fever, fatigue, shortness of breath, malaise [pathologyoutlines.com]
- Pathologist
Special stains can be performed on the lung specimen, such as immunostains, in difficult cases by the pathologists Arterial blood gas analysis will reveal the quantity of oxygen and carbon-dioxide in blood. [dovemed.com]
[…] commonly included in vectors used in genetic engineering work conducted in mammalian cells, as it is a strong promoter and drives constitutive expression of genes under its control. [11] History [ edit ] Cytomegalovirus was first observed by German pathologist [en.wikipedia.org]
However, this method is invasive and has a limited sensitivity that depends on the sampling site and pathologist’s skills. [annalsofintensivecare.springeropen.com]
(Garbe) Staff Pathologist, Service d'Anatomo-Pathologie. (Zandotti) Staff Virologist, Laboratoire de Virologie. (Thomas) Staff Surgeon, Service de Chirurgie Thoracique. (Gouin) Professor, Departement d'Anesthesie-Reanimation. [anesthesiology.pubs.asahq.org]
- Recurrent Infection
Most people will have had a CMV infection by the time they are adults. It isn’t generally serious. But the virus can remain inactive in your body for many years and cause recurrent infections. [cancerresearchuk.org]
Once a person becomes infected, the virus remains alive, but usually dormant within that person’s body for life. There are two different types of infection: primary CMV and recurrent CMV infection. [americanpregnancy.org]
After treatment doses have been administered, an additional 1-3 months of appropriate prophylaxis should be considered to minimise the risk of recurrent infection. [patient.info]
Adult cytomegalovirus infection in the immunocompromised host CMV infection in transplant recipients may be primary or recurrent. [emedicine.medscape.com]
Recurrent infection could be due to reactivation (if the detected strain is the same as the primary infecting strain) which is the most common mechanism of acquiring the disease in adulthood, especially in immunocompromized population (seropositivity [annalsofintensivecare.springeropen.com]
- Chills
She had fevers, chills, a red rash, muscle pain, and joint pains. She works in a daycare center, and some of her colleagues had similar symptoms. This resolved in 1 week. Today, there are no significant findings on physical exam. [medbullets.com]
If you are a healthy adult, call your doctor if you have severe abdominal pain, vomiting or fevers that last longer than 48 hours or if you have significant fatigue, sweats, chills or are losing weight. [drugs.com]
In some people, the virus causes mild symptoms that mimic the flu or infectious mononucleosis, such as fever, chills, body aches, headache, swollen lymph nodes *, sore throat, and fatigue. [humanillnesses.com]
Respiratoric
- Cough
Hypoxia, if extreme, may be fatal. cytomegalovirus pneumonia Pulmonology A viral pneumonia characterized by fever, non-productive cough, SOB and association with PCP, especially in AIDS; hypoxia, if extreme, may be fatal. [medical-dictionary.thefreedictionary.com]
A 24-year-old male was admitted to the hospital with complaints of cough, fever and dyspnoea. He was receiving immunosuppressive therapy for polyarteritis nodosa. [ncbi.nlm.nih.gov]
Fever, lymphadenopathy and flu-like symptoms, in what is termed CMV mononucleosis, with or without the presence of a cough, is the most frequently described clinical presentation. [symptoma.com]
All patients of CMV pneumonia had dyspnea, 90% had fever and 71% had cough. [erj.ersjournals.com]
- Dyspnea
Fever and dyspnea were the most frequent symptoms. The most frequent radiological signs were bilateral pulmonary infiltrates. Six cases were complicated by hemophagocytic lymphohistiocytosis. [ncbi.nlm.nih.gov]
All patients of CMV pneumonia had dyspnea, 90% had fever and 71% had cough. [erj.ersjournals.com]
A 29 year-old female with a history of systemic lupus erythematosus presented with a seven-day history of fever, dyspnea and a non-productive cough. [swjpcc.com]
[…] may be present: CMV mononucleosis CMV pneumonia : interstitial pneumonitis Etiology: immunocompromised patients (e.g., following bone marrow transplant or in HIV / AIDS patients with CD4 ≤ 50 cells/mm 3 ) Clinical findings: fever, nonproductive cough, dyspnea [amboss.com]
- Dry Cough
cough If you're HIV-positive, your chance of becoming sick with CMV is greatest when your CD4 count is below 100. [webmd.com]
The signs and symptoms of CMV Pneumonia are: Fever, dry cough, and shortness of breath, are the most common symptoms. [dovemed.com]
- Tachypnea
CONCLUSIONS: CMV pneumonia should always be suspected in IBD patients who present with fever and tachypnea, especially if the latter is worsening and/or is associated with dyspnea. Treatment must be early and specific. [ncbi.nlm.nih.gov]
Conclusion We report an acute CMV infection case, which presented with fever, cough, sputum and tachypnea. The latter deteriorated rapidly and is associated with respiratory failure. [aclr.com.es]
Gastrointestinal
- Diarrhea
Fever, abdominal pain, diarrhea, rash, and dyspnea occurred after HSCT. The young man developed severe CMV infection with CMV detected in the bronchoalveolar lavage fluid and gastrointestinal tract. [ncbi.nlm.nih.gov]
Hepatitis-like symptoms and signs may include appetite loss, yellow eyes, nausea, and diarrhea. [medicinenet.com]
[…] retinal vessels resembling cotton-wool spots, retinal detachment ) Differential diagnoses: HIV retinopathy, herpes simplex retinitis, varicella zoster retinitis, toxoplasmosis CMV esophagitis : and/or CMV colitis : odynophagia, abdominal pain, bloody diarrhea [amboss.com]
Symptoms can include painful and difficult swallowing, nausea, vomiting, abdominal pain, yellow skin and watery or bloody diarrhea. [drugs.com]
You could have: Blind spots or moving black spots, called "floaters," in your eyesight Blurred vision Blindness Diarrhea Belly pain Painful or difficult swallowing Pain, weakness, or numbness at the base of your spine that makes walking a struggle In [webmd.com]
- Loss of Appetite
Symptoms Cough Fatigue Fever General discomfort, uneasiness, or ill feeling (malaise) Loss of appetite Muscle aches or joint pains Shortness of breath Shortness of breath on exertion Sweating, excessive (night sweats) Low oxygen levels in the blood (hypoxemia [dxline.info]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) The goal of treatment is to use antiviral drugs to [medlineplus.gov]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) Exams and Tests The doctor or nurse will perform a [m.ufhealth.org]
Examination reveals crackles in the lungs and low oxygenation Loss of appetite, discomfort, general malaise or tiredness Muscular ache, fatigue, excessive sweating (at nights) Coughing blood with severe pneumonia Co-existing infections in the lung, such [dovemed.com]
Cardiovascular
- Hypertension
His earlier medical history included hypertension, diabetes, and gout. His previous family history was unremarkable. His vital signs were as follows: body temperature: 36.5 (97.7 ), heart rate: 98 beat per minute (BPM), blood pressure: 98/61 mmHg. [aclr.com.es]
Musculoskeletal
- Arthritis
Cytomegalovirus pneumonia in a patient with rheumatoid arthritis treated with low dose methotrexate and prednisone. [ard.bmj.com]
[…] who have undergone bone marrow transplant or organ transplant, those on chemotherapy for cancer treatment, those who have been treated with high dose steroids or other immune-suppressing medications for diseases, such as Crohn’s disease, rheumatoid arthritis [dovemed.com]
Secundary HPS to inflammatory/autoimmune disorders, including systemic lupus erythematosus, rheumatoid arthritis and Still´s disease, or due anticonvulsants such as phenytoin and carbamazepine [ 34, 45, 46 ]. [intechopen.com]
Human Parvovirus B19 and arthritis. Behring Inst Mitt. 1990; 85 :64–68. [ PubMed ] [ Google Scholar ] 50. Dembinski J, Eis-Hübinger AM, Maar J, Schild R, Bartmann P. Long term follow up of serostatus after maternofetal parvovirus B19 infection. [ncbi.nlm.nih.gov]
Skin
- Sweating
Symptoms experienced include Symptoms of CMV pneumonia include cough, fever, night sweats, respiratory distress, hypoxia, myalgia, arthralgia, and fatigue. Radiological evidence of disease can sometimes precede outward signs of infection. [symptoma.com]
Symptoms Cough Fatigue Fever General discomfort, uneasiness, or ill feeling (malaise) Loss of appetite Muscle aches or joint pains Shortness of breath Shortness of breath on exertion Sweating, excessive (night sweats) Low oxygen levels in the blood (hypoxemia [dxline.info]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) The goal of treatment is to use antiviral drugs to [medlineplus.gov]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) Exams and Tests The doctor or nurse will perform a [m.ufhealth.org]
If you are a healthy adult, call your doctor if you have severe abdominal pain, vomiting or fevers that last longer than 48 hours or if you have significant fatigue, sweats, chills or are losing weight. [drugs.com]
- Night Sweats
Symptoms experienced include Symptoms of CMV pneumonia include cough, fever, night sweats, respiratory distress, hypoxia, myalgia, arthralgia, and fatigue. Radiological evidence of disease can sometimes precede outward signs of infection. [symptoma.com]
Symptoms Cough Fatigue Fever General discomfort, uneasiness, or ill feeling (malaise) Loss of appetite Muscle aches or joint pains Shortness of breath Shortness of breath on exertion Sweating, excessive (night sweats) Low oxygen levels in the blood (hypoxemia [dxline.info]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) The goal of treatment is to use antiviral drugs to [medlineplus.gov]
Symptoms may include: Cough Fatigue Fever General discomfort, uneasiness, or ill feeling ( malaise ) Loss of appetite Muscle aches or joint pains Shortness of breath Sweating, excessive (night sweats) Exams and Tests The doctor or nurse will perform a [m.ufhealth.org]
sweats, muscle and joint pain Note : positive culture, serology or PCR may not represent evidence of illness Diagnosis is based on identification of viral inclusions in biopsy material Acute CMV infection leads to transient but severe immunosupression [pathologyoutlines.com]
Workup
The diagnosis of CMV pneumonia combines both clinical observation and medical imaging. Chest X-ray and computerized tomography (CT) scan are the relevant imaging techniques. They may show ground glass or patchy opacities across both lung fields [5] [6]. Despite this, possible X-ray and CT findings are variable.
Laboratory tests involve collecting tissue samples from the blood, urine or alveoli through bronchoalveolar lavage. These samples are used for serology through the means of immunological assays, viral culture, and DNA polymerase chain reaction (PCR). Caution should be exercised when interpreting results, as they can be misleading. Histopathologic diagnosis, for which a lung biopsy is needed, is more accurate but may prove hazardous for bedridden patients [7].
X-Ray
- Pulmonary Infiltrate
A 61-year-old woman who had undergone an operation for thymoma 17 years previously suddenly became dyspneic and showed bilateral pulmonary infiltrates on a chest radiograph. [ncbi.nlm.nih.gov]
There are few studies reported the correlation of clinical, and pulmonary infiltration with histopathological evidence of CMV pneumonia. [erj.ersjournals.com]
In our previously reported study, patients were also classified as having probable CMV pneumonia, defined by an interstitial pulmonary infiltrate, lung dysfunction, evidence of CMV disease or infection elsewhere, and no other explanation for the infiltrate [journals.lww.com]
The only morbidity occurred in two patients who had fever and a pulmonary infiltrate in the lung segments subjected to lavage within 24 hours after the procedure. [nejm.org]
- Pulmonary Infiltrates
A 61-year-old woman who had undergone an operation for thymoma 17 years previously suddenly became dyspneic and showed bilateral pulmonary infiltrates on a chest radiograph. [ncbi.nlm.nih.gov]
There are few studies reported the correlation of clinical, and pulmonary infiltration with histopathological evidence of CMV pneumonia. [erj.ersjournals.com]
In our previously reported study, patients were also classified as having probable CMV pneumonia, defined by an interstitial pulmonary infiltrate, lung dysfunction, evidence of CMV disease or infection elsewhere, and no other explanation for the infiltrate [journals.lww.com]
The only morbidity occurred in two patients who had fever and a pulmonary infiltrate in the lung segments subjected to lavage within 24 hours after the procedure. [nejm.org]
- Bilateral Pulmonary Infiltrates
A 61-year-old woman who had undergone an operation for thymoma 17 years previously suddenly became dyspneic and showed bilateral pulmonary infiltrates on a chest radiograph. [ncbi.nlm.nih.gov]
Colonoscopy
- Colitis
Autopsy revealed CMV colitis based on UC, and CMV pneumonia with diffuse alveolar damage. [ncbi.nlm.nih.gov]
The patient was treated with mesalamine for suspected ulcerative colitis, with minimal effect. A positive faecal occult blood test result raised the suspicion of ischaemic colitis. [mja.com.au]
Autopsy revealed multisystemic Cytomegalovirus infection, including extensive bilateral interstitial pneumonia, gastritis, colitis, hepatitis, and encephalitis. [geocities.ws]
Convert to ICD-10-CM : 078.5 converts approximately to: 2015/16 ICD-10-CM B25.9 Cytomegaloviral disease, unspecified Approximate Synonyms Chorioretinitis due to cytomegalovirus (disorder) CMV chorioretinitis CMV colitis CMV enteritis CMV gastritis CMV [icd9data.com]
CMV colitis is rare in patients with Crohn´s disease or mild-moderate ulcerative colitis. [intechopen.com]
Other Pathologies
- Viral Inclusion Body
Some of the alveolar spaces were lined by large cells containing homogenous dark purple viral inclusion bodies, surrounded by a characteristic halo, suggestive of CMV infection [Figure 3]. [ijpmonline.org]
The pathologic hallmark of CMV infection is an enlarged cell with viral inclusion bodies. Cells that exhibit cytomegaly are also seen in infections caused by other Betaherpesvirinae. [emedicine.medscape.com]
Treatment
Antiviral treatment with ganciclovir or foscarnet was associated with improved outcome compared with no antiviral treatment. [ncbi.nlm.nih.gov]
Prognosis
Prognosis was poor in patients who were ventilator-dependent at initiation of therapy (median survival 17 days), with only 1 long-term survivor. [ncbi.nlm.nih.gov]
However, screening for congenital CMV infection is not currently recommended in the UK. [ 13 ] Prognosis The prognosis of patients with CMV hepatitis is generally good. Most patients recover completely. [patient.info]
Outlook (Prognosis) Antiviral medications stop the virus from copying itself, but do not destroy it. CMV itself suppresses the immune system, and may increase the risk of other infections due to the additional immunosuppression. [dxline.info]
[…] latent infection replication of host cells (including epithelial cells, macrophages, and neurons) results in viremia and symptoms from primary infection cellular immunity is crucial in clearing this virus Associated conditions congenital CMV infection Prognosis [medbullets.com]
Prognosis depends on how severe the CMV infection is and the person's underlying immune system. Giving antiviral medication in people who have a very weak immune system, such as bone marrow transplant recipients, improves prognosis. [medicinenet.com]
Etiology
Potential viral etiologies should therefore be considered in cancer patients with pneumonia receiving non-transplantation chemotherapy-regimens, particularly if steroids are a component of their therapy. [ncbi.nlm.nih.gov]
Pneumonia is inflammation of the lung, which includes infectious and non-infectious etiologies. It is a subset of the medical lung diseases. This article primarily deals with the infectious pneumonias. [librepathology.org]
Etiology Pathogen : cytomegalovirus ( CMV, human herpes virus 5, HHV-5 ) Transmission Blood transfusions Sexual transmission Droplet transmission Transplant-transmitted infection (e.g., bone marrow, lungs, kidneys) References: [1] [2] [3] Pathophysiology [amboss.com]
Epidemiology
Editors Charles Dela Cruz and Richard Wunderlink have assembled an expert team of authors on topics such as: Epidemiology of Viral Pneumonia; Diagnostic Testing for Viral and Atypical Infections;Lung Microbiome: Atypical Infections and Viruses; RSV Pneumonia [books.google.com]
Epidemiology Epidemiological data refers to the US, unless otherwise specified. [amboss.com]
Our research in immunocompromised patients takes a multifaceted approach to identifying epidemiologic risk factors for CMV infection, defining the viral kinetics, and improving prevention, diagnosis and treatment strategies. [research.fhcrc.org]
Congenital cytomegalovirus infection: review of the epidemiology and outcome. Obstet Gynecol Surv. 2002; 57 :245–256. [ PubMed ] [ Google Scholar ] 8. Fowler KB, Stagno S, Pass RF. [ncbi.nlm.nih.gov]
Introduction Classification cytomegalovirus (CMV) or human herpesvirus-5 (HHV-5) double-stranded DNA virus largest virus that causes human infections transmission via body fluids or vertical transmission Epidemiology incidence very common risk factors [medbullets.com]
Pathophysiology
Etiology Pathogen : cytomegalovirus ( CMV, human herpes virus 5, HHV-5 ) Transmission Blood transfusions Sexual transmission Droplet transmission Transplant-transmitted infection (e.g., bone marrow, lungs, kidneys) References: [1] [2] [3] Pathophysiology [amboss.com]
The role viremia plays in the pathophysiology of CMV disease is unknown. Life-threatening CMV pneumonia may develop in immunocompromised patients, with the incidence varying based on the type of transplant received. [emedicine.medscape.com]
Because BOOP represent way in which the lung may respond to an inflammatory stimulus, the key pathophysiological findings are related to the inflammatory pathway. [aclr.com.es]
Pathophysiology After the initial infection, CMV remains in a persistent state in the host. The cells of the myeloid lineage constitute an important reservoir. [ispub.com]
Pathophysiology Causal agent CMV or HHV-5 (type 5 of Human Herpes Virus) is a double-stranded DNA virus. It is the largest of the human herpes viruses with a 230 kb genome encoding 165 genes [ 11 ]. [omicsonline.org]
Prevention
In addition, the use of ganciclovir is becoming increasingly important as an early means of preventing serious disease. [ncbi.nlm.nih.gov]
Different preventative strategies: Prophylaxis treats patients continuously with an antiviral from the day of engraftment to 100 days post-transplant in order to prevent recurrence or reactivation of CMV infection. [ti.ubc.ca]
Prevention The following have been shown to help prevent CMV pneumonia in certain patients: Using organ transplant donors who don't have CMV Using CMV-negative blood products for transfusion Using CMV-immune globulin in certain patients Preventing AIDS [dxline.info]
A new study led by David Fidock, PhD, identifies a class of compounds found to be effective in preventing transmission of Plasmodium falciparum parasites from an infected host to mosquitoes. [cumc.columbia.edu]
References
- Kotloff RM, Ahya VN, Crawford SW. Pulmonary complications of solid organ and hematopoietic stem cell transplantation. Am J Respir Crit Care Med. 2004;170(1):22–48.
- Singh N, Dummer JS, Kusne S, et al. Infections with cytomegalovirus and other herpesviruses in 121 liver transplant recipients: transmission by donated organ and the effect of OKT3 antibodies. J Infect Dis. 1988;158(1):124–131.
- Vigil KJ, Adachi JA, Chemaly RF. Viral pneumonias in immunocompromised adult hosts. J Intensive Care Med. 2010;25(6):307–326.
- Boeckh M, Ljungman P. How we treat cytomegalovirus in hematopoietic cell transplant recipients. Blood. 2009;113(23):5711–5719.
- Moon JH, Kim EA, Lee KS, Kim TS, Jung KJ, Song JH. Cytomegalovirus pneumonia: high-resolution CT findings in ten non-AIDS immunocompromised patients. Korean J Radiol. 2000;1(2):73–78.
- Franquet T, Lee KS, Muller NL. Thin-section CT findings in 32 immunocompromised patients with cytomegalovirus pneumonia who do not have AIDS. AJR Am J Roentgenol. 2003;181(4):1059–1063.
- Zhao XS, Liu DH, Xu LP, et al. [Clinical features of cytomegalovirus pneumonia after allogeneic hematopoietic stem cell transplantation] Beijing Da Xue Xue Bao. 2009;41(5):548–553.