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An Introduction to Parasitism
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
A related concept is an opportunistic parasite, which takes advantage of particular circumstances to initiate an infection in a host that it normally does not infect or in which it does not normally cause disease. A person with a compromised immune system, as might occur in people infected with the human immunodeficiency virus (HIV), may become susceptible to infections with organisms such as the yeast-like fungus Pneumocystis jirovecii, or the apicomplexan protozoa Cryptosporidum parvum or Toxoplasma gondii, all of which would normally be held in check by a person with an intact immune system. Opportunistic infections become ever more relevant in a world where many people have compromised immune systems owing to infections such as HIV or medical procedures such as organ transplants.
Mucormycosis
Published in Srijan Goswami, Chiranjeeb Dey, COVID-19 and SARS-CoV-2, 2022
Soumyajit Dutta, Srijan Goswami
Individuals with suppressed immune systems are more susceptible to opportunistic infections. The complications associated with COVID-19 occur due to the cytokine storm happening inside the patient's body. The cytokine storm comprising of interleukin-1, interleukin-6, interleukin-8, tumor necrosis factor-α, and various chemokines damage vital organs like the liver, heart, lungs, and kidneys, thus leading to a state of multisystem organ failure. In order to protect the patient from multisystem organ failure, immunosuppressive treatments are provided. These immunosuppressive treatments include steroids and associated immunosuppressive drugs, the dosage and duration of which far exceeded the safety recommendations of the World Health Organization. This treatment not only induces an immunosuppressive state but also leads to an increase in blood sugar levels, thus rendering the patient a higher susceptibility to COVID-associated mucormycosis. Also, individuals under conventional treatment for malignancies, burns, or traumatic injuries, or who have undergone organ or bone marrow transplantation, suffer from a drug-induced immunosuppressive state. These drugs maintain a systemic immunosuppressive state and thus make an individual more susceptible to opportunistic infections (CDC, 2021; ICMR, 2021; Pongas et al., 2009) (Figure 11.4).
Unexplained Fever In Hematologic Disorders Section 1. Benign Hematologic Disorders
Published in Benedict Isaac, Serge Kernbaum, Michael Burke, Unexplained Fever, 2019
The acquired immune deficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV) which affects the helper/inducer T-lymphocytes (T4). AIDS is characterized by general lymphadenopathy (cervical, axillary, and especially occipital), splenomegaly, atypical lymphocytosis, severe opportunistic infections, Kaposi’s sarcoma, and the presence of HIV antibodies. General symptoms like fever, skin rash, and diarrhea can be present, even in the absence of a superimposed opportunistic infection.4,5
Anti-cytomegalovirus preemptive therapy to prevent cytomegalovirus disease in HIV-infected patients: a systematic review
Published in Infectious Diseases, 2023
Prenali Dwisthi Sattwika, Yanri Wijayanti Subronto, Heni Retnowulan, Karina Ambar Sattwika, Detty Siti Nurdiati
Opportunistic infections in people with acquired immune deficiency syndrome (AIDS) due to infection of the human immunodeficiency virus (HIV) are important causes of morbidity and mortality. Administration of highly active antiretroviral therapy (HAART) for the first time in 1995 could reduce the incidence of opportunistic infections by 55% from 1992 to 1997 [1], however, preventive strategies remain crucial. Prophylactic regimen includes administration of anti-CMV therapy to immunosuppressed patients who are at risk of CMV infection. Meanwhile, preemptive regimen involves administration of anti-CMV therapy to the patient with evidence of asymptomatic CMV infection detected by CMV assay. A CD4+ cell count of <200 cells/μL is a condition under which prophylaxis can be considered. In the HAART period, HIV-infected patients with low CD4+ cell count and the presence of cytomegalovirus (CMV) dissemination in peripheral blood (detection of plasma CMV DNA and high pp65 antigenemia) are at risk of developing CMV disease [2].
Cytomegalovirus viremia and advanced HIV disease: is there an argument for anti-CMV treatment?
Published in Expert Review of Anti-infective Therapy, 2023
Caleb P. Skipper, Mark R. Schleiss
The concept of preventing disease from opportunistic infections in persons with advanced HIV disease until immune reconstitution occurs already has strong precedent. A high-impact example of this is the prophylactic use of trimethoprim/sulfamethoxazole in persons with CD4+ counts of <200 cells/mm3 to prevent pneumonia from Pneumocystis jirovecii, and to prevent cerebral Toxoplasma gondii infection in those with CD4+ counts of <100 cells/mm3. The demonstration of reduced morbidity/mortality from these opportunistic infections with chemoprophylaxis until a CD4+ recovery is observed has changed guidelines and standards of care [58–61]. A demonstrable survival benefit from anti-CMV therapy in high-risk persons could similarly lead to antiviral therapy being included in HIV package of care guidelines.
In vivo and in vitro evaluation of pulmonary administration of itraconazole nanostructured lipid carriers for pulmonary aspergillosis
Published in Drug Development and Industrial Pharmacy, 2023
Yanming Wang, Zhang Chenghao, Zhaoli Wu, Xinran Cui, Jinmei Ren, Jingling Tang
Pulmonary aspergillosis is an infectious or non-contagious disease caused by ubiquitous fungi of the genus Aspergillus [1]. It is a common fungal lung disease that leads to death in immunosuppressed individuals and critically ill patients. Organism and environmental factors are the major predisposing factors that lead to the development of opportunistic infections. These factors can be caused by the harsh environments that professionals and people who develop chronic lung disease, diabetes, and other illnesses experience [2]. Pulmonary aspergillosis clinically falls into three types: invasive pulmonary aspergillosis (IPA), Aspergillus species, and allergic bronchopulmonary aspergillosis (ABPA). IPA, which causes clinical signs including dry cough, chest pain, and respiratory failure, is the most common [3]. Antifungal drugs are usually used for treating pulmonary aspergillosis [4]. Fungal infections are frequently treated with four different types of antifungal medicines, including fluorinated pyrimidines, polyene macrolides, triazoles, and echinocandins [5]. Amphotericin B is commonly used to treat systemic fungal infections; however, it may cause significant toxicities such as nausea, fever, and chills with renal insufficiency when intravenously administrated. The toxicities above often lead to treatment discontinuation in severe cases [6]. Currently, triazole antifungal drugs can be used to replace amphotericin B, although their pharmacokinetic and activity profiles differ.