Disseminated Fungal Infection. Aspergillus and Aspergillosis

Disseminated Fungal Infection Aspergillus and Aspergillosis What is Aspergillus? • It is a genus of around 200 fungi (moulds) found worldwide. • Fungi are identified in the lab by their structure and appearance. They may appear as round single cells like yeast, or made of chains of cells called hyphae. • Aspergillus is a filamentous fungus as opposed to yeast which is single celled. • Fungi reproduce by forming tiny spores which can easily be airborne. Conidial head or fruiting body of Aspergillus - producing spores Aspergillus • *Aspergillus is a widely distrisbuted genus, most are saprophytes on dead organic materials(fruits,jams ,leather, wood,……..) on orange, aspergillus form blue mould. • On otherhand some species are parasites. • *A.flavus,A.fumigtus and A.niger cause diseases to human and animals known asperilloses also they may cause disease for human ear called otomycosis. • A.flavus produce mycotoxins. • A. fumigatus give fumes which may contaminate the environment and cause respiratory tract infections of human. • A.niger is very important for industry it produce about (1819)enzymes including: cellulases, xylanases amaylases ,pectinases,… Sources of Infection? Aspergillus species are found in : – – – – – – – – – Soil Air; spores may be inhaled Water / storage tanks in hospitals etc Food Compost and decaying vegetation Fire proofing materials Bedding, pillows Ventilation and air conditioning systems Computer fans Aspergillus spores Aspergillus , Aspergillus fumigatus spore forming head (Electron micrograph) Why is Aspergillus important? . • Some Aspergillus species cause serious disease in humans and animals – it is pathogenic. • Some Aspergillus species produce enzymes which have important industrial applications. • Aspergillus can produce mycotoxins – these are often found in contaminated foodstuff and are hazardous to the consumer. Aspergillus Mycotoxins • Mycotoxins are chemical products of fungi that have the capacity to damage animal health and contaminate crops. • Repeated aflatoxin ingestion in man has been linked to liver cancer. • Mycotoxins (aflatoxins) produced by Aspergillus parasiticus and A. flavus are commonly found to contaminate corn, peanuts, and other crops used for animal feedstuff. High temperature and humidity increase chances of contamination. Where is Aspergillus found? • Its natural habitat is in hay and compost. • Aspergillus spores are easily airborne and we normally breathe in 100-200 spores daily. • Some species withstand heat eg; Aspergillus fumigatus (pathogenic type, 15°C to 53°C). • these are commonly found in compost. The spores of A. fumigatus are produced on specialized conidiophores ranging from 1.0 to 3.0 micrometer in diameter and deposited in the lower respiratory tract. The hyphae of A. fumigatus are 3 to 5 micrometer in diameter, septate, and often branch typically at a 45° angle. The life cycle of Aspergillus Spores inhaled Germination Mass of hyphae (plateau phase) Hyphal elongation and branching Which species of Aspergillus are pathogens? • The most common causing invasive disease are Aspergillus fumigatus and Aspergillus flavus. • The most common causing allergic disease are Aspergillus fumigatus and Aspergillus clavatus. Aspergillus fumigatus causes all manifestations of aspergillosis which is why it is one of the most important from a disease point of view. Aspergillus flavus causes invasive disease (particularly sinusitis and plant disease) and produces aflatoxin. Aspergillus clavatus is common in hay barns and causes allergy - probably because it does not grow well at 37°C, it does not cause invasive disease. Aspergillus as a pathogen in manAspergillosis is a group of diseases caused by Aspergillus. The symptoms – fever, a cough, chest pain or breathlessness occur in many other illnesses so diagnosis can be hard. Usually only patients with already weakened immune systems or who suffer other lung conditions are susceptible. In man the major forms of disease are: 1. 2. 3. Allergic aspergillosis (affects asthma, cystic fibrosis and sinusitis patients). Acute invasive aspergillosis (risk increases if patient has weakened immunity such as some cancer patients and those on chemotherapy,Netropenia). Disseminated invasive aspergillosis (widespread through body). People with fully functional immune systems are very unlikely to suffer severe fungal disease. Patients with impaired immune system are very susceptible to invasive fungal infection like Aspergillosis White blood cells are important for attacking fungal infections. Antibodies however are not useful in fighting most fungal infections. Clinical Manifestation of Aspergillosis • • • • 1.Invasive Aspergillosis(IA) 2.Acute,Chronic invasive Sinusitis 3.Endophtalmitis 4.Endocarditis(Prosthetic Valve of Endocarditis or pacemarker) • 5.Aspergilloma(Fungus Ball in lung and Hemptesia) • 6.Allergic Bronchopulmonary Aspergillosis(ABPA) • 7.Cutaneous Aspergillosis(in burn Patients, withA.niger) Corticosteriod therapy, Chemotrapy,Radiotrapy Clinical Sign of IA • • • • High Fever, Cough Secretion of Mucoid and bloody sputum Patients need to oxygen in advanced stage With developing of disease,large percent of lung tissue impaired(Necrosis,ischaemia) and fill with haphae of Aspergillus. • With developing of diseases and un response to Antifungal drugs lead to death of cases. • Survival rate of patients almost is low(0-50%) Aspergillomas are formed when the fungus grows in a clump in a lung cavity. The cavity is often created by a previous condition. Cavities in the lung may be caused by diseases such as: Tuberculosis Lung Cancer Lung Abscess Sarcoidosis Cystic fibrosis The most common species of fungus that causes disease in humans is Aspergillus fumigatus. Chest graphy of fungus ball in left Relative risk of Aspergillus infection Patients whose immune system is already weakened are most susceptible. Those most at risk include some cancer and leukaemia patients, those on chemotherapy and transplant patients. Frequency of aspergillosis Allergic aspergillosis Allergic sinusitis Aspergilloma Immune malfunction Normal immune function Immune hyper-reactivity Frequency of aspergillosis Acute invasive aspergillosis Laboratory Methods for Aspergillosis • 1.Direct examination of sputum,BAL by KOH • 2.Culture on SDA Medium incubation 37days • 3.Detection of Galactomannan Antigen in fluids (BAL,Serum),GM test by ELISA • 4.Histopatology evaluation • 5.X-ray and CT-Scan of tissue • 6.Molecular Methods(Real-time PCR) Symptoms & Diagnosis Symptoms The first noticeable symptoms of ABPA are usually progressive worsening of your asthma symptoms such as wheezing and shortness of breath. Other symptoms of ABPA include: • Cough with brownish flecks or bloody mucous • Fever • General weakness or malaise Diagnosis Diagnosis for ABPA is determined by health history, x-rays or CT scans, allergy skin testing and/or blood tests.Increase Ig E level in serum of patients Asthma medications such as oral corticosteroids open the airways and make it easier to cough and clear out the fungus. The use of this medication depends upon the individual and the severity of ABPA In addition, an oral anti-fungal such as itraconazole may be recommended, although it is somewhat controversial regarding its effectiveness.