Introduction to virus structure, classification, replication, and hosts
Avindra Nath, Joseph R. Berger in Clinical Neurovirology, 2020
Several terms are used to describe the various types of viral infections that can occur in people. The more common type of infection that a virus can cause is an acute infection, which is characterized by a rapid onset, visible symptoms, and short duration (e.g., influenza virus). A chronic or persistent infection, unlike acute infections, which can end in weeks, can last from years to indefinitely. In such cases, the virus often reproduces at a much slower rate and can even result in an infected individual being apparently symptom-free (e.g., herpesviruses and hepatitis B virus). A latent virus infection refers to viruses that stop reproducing as they enter a state of dormancy, only to become active again at a later time point (e.g., herpesviruses). Like patients with chronic infections, the patient with a latent virus infection may not exhibit any symptoms until the virus becomes activated.
Ticks
Gail Miriam Moraru, Jerome Goddard in The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
In ticks, tularemia infection occurs in both the gut and body tissues and hemolymph fluid (tick blood). Infection is known to persist for many months and even years in some species. Tularemia organisms may be passed from tick stage to tick stage and to the offspring of infected female ticks. The three major North American ticks involved in transmission of tularemia organisms are the lone star tick, Amblyomma americanum; the Rocky Mountain wood tick, Dermacentor andersoni; and the American dog tick, D. variabilis.75 Both the lone star tick and the American dog tick occur over much of the eastern United States; the Rocky Mountain wood tick occurs in the West. All three tick species are avid human biters. In Central and Western Europe, Ixodes ricinus is probably a vector. Dermacentor nuttalli may be a vector in Russia. D. dagestanicus (= niveus) and Rhipicephalus pumilio may be vectors in Kazakhstan.
Recurrent respiratory papillomatosis
Declan Costello, Guri Sandhu in Practical Laryngology, 2015
The fundamental question is why is there so much HPV yet so little RRP? The reality is that the majority of humans have probably had at least a transient HPV infection. In some, the virus is cleared, in others it remains as a dormant commensal, and in a small proportion it results in a persistent infection with wart/papilloma formation. Persistent infection may be related to (as yet unspecified) differences in host immunity and this may in turn be due to the host’s genetic make-up. Alternatively, there may be viral factors. Indeed there are 19 variants of HPV-6 and 10 variants of HPV-11. The variants have been shown to differ in their activity (at least in vitro) and this may explain why some have more aggressive disease than others for the same HPV type.3 Furthermore, it is clear that in cervical disease there is a worse prognosis if there are multiple different HPV types present.4 It is reasonable to assume this to be the same for RRP, as up to seven different types of HPV have been identified in papillomas from RRP patients.5
Registered clinical trials investigating treatment of long COVID: a scoping review and recommendations for research
Published in Infectious Diseases, 2022
Felicia Ceban, Alexia Leber, Muhammad Youshay Jawad, Mathew Yu, Leanna M. W. Lui, Mehala Subramaniapillai, Joshua D. Di Vincenzo, Hartej Gill, Nelson B. Rodrigues, Bing Cao, Yena Lee, Kangguang Lin, Rodrigo B. Mansur, Roger Ho, Matthew J. Burke, Joshua D. Rosenblat, Roger S. McIntyre
Persistent symptoms are not uncommon following infection with viral or bacterial agents. For example, outbreaks of fatigue syndrome (including general malaise and neurological abnormalities) were documented following the Spanish influenza of 1918 [20] and the 2002–2004 severe acute respiratory syndrome (SARS) epidemic [21,22]. Previous psychoneuroimmunological research has established links between pro-inflammatory cytokines and neuropsychiatric symptoms including depression and cognitive impairment [23–25]. However, despite their long history, treatments with robust efficacy for post-viral syndromes and related conditions, such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), have not been developed. Chronic ‘unexplained’ (± post-infectious) symptoms remain a controversial and poorly understood topic in medicine. A spectrum of sub-populations may exist, and some patients’ symptoms may root from complex brain network dysfunction seen in functional neurological disorders and/or somatic symptom disorders [26]. The pervasiveness of COVID-19 provides the exigency to advance our understanding of post-infectious syndromes and related conditions.
Intravenous vs intravenous plus aerosolized colistin for treatment of ventilator-associated pneumonia – a matched case–control study in neonates
Published in Expert Opinion on Drug Safety, 2020
Kashif Hussain, Muhammad Sohail Salat, Gul Ambreen, Ambreen Mughal, Sidra Idrees, Mehreen Sohail, Javaid Iqbal
At the completion of colistin therapy clinical outcomes were classified on the basis of change in presenting signs and symptoms of infection: (a) clinical cure = complete resolution, (b) clinical failure = worsening or persistence, (c) clinical improvement = incomplete resolution, (d) infection recurrence, i.e. a new infection event at ≥72 hours after complete resolution of a previous event. Clinical improvement or cure was defined as a clinical success [31]. The microbiological outcome was assessed at the end of colistin treatment and classified into (a) eradication of the causative organism – i.e. no growth of the pathogen in the final culture of specimens during the entire hospitalization, (b) persistence of the causative organism – i.e. persistent growth of the responsible pathogen regardless of the clinical outcome of the infection, (c) regrowth of the causative organism – i.e. reisolation of the same pathogen regardless of the clinical outcome of the infection, or (d) colonization – i.e. persistence or regrowth of the pathogen without symptoms and signs of infection [31]. Neonatal death during colistin therapy with persistent signs of pneumonia was defined as VAP-related mortality.
Eosinopenia and increased markers of endothelial damage are characteristic of COVID-19 infection at time of hospital admission
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2022
Marouscha P. de Vries, Nieky Mohammadnia, Suat Simsek, Marianne Schoorl
After recovery, there have been reports of persistent fatigue, independent on the severity of the infection. Together with muscle pain and dry syndrome, it is associated with a systemic autoimmune disease, which can be developed during an infection and persist after its control [3]. There are also some cases of autoimmune disease reported after a COVID-19 infection in which autoantibodies against smooth muscles (SMA) were produced. These autoantibodies are usually found in patients with hepatitis or other liver diseases [4]. Although liver cells by itself seem not to be affected, because the lungs are the main target of infection, it is hypothesized that they play a role in the raise of a systemic disease [5]. Histopathological findings suggest that the intrahepatic blood vessel network is disturbed [5]. In addition to targeting the lung parenchyma, the virus may be able to induce changes in the cardiovascular system, coagulation cascade and endothelial layer of blood vessels. A correlation between the levels of vascular adhesion molecules and the severity of the infection is found. Up to now, it is not known whether these changes are directly related to the virus infection or whether SARS‐CoV‐2 triggers a series of reactions leading to striking vascular alterations. [6]
Related Knowledge Centers
- Adaptive Immune System
- Inflammation
- Innate Immune System
- Tissue
- Toxin
- Virus
- Immune System
- Pathogen
- Host
- Pathogenic Bacteria