Influenza Causative Agent Orthomyxovirus Influenza A virus Infulenza B virus SS RNA virus 8 linear segments Enveloped with spikes H spike N spikes

Signs and symptoms Acute symptoms decline within a week Sudden high fever, pharyngitis, congestion, dry cough, headache and myalgia Acute symptoms decline within a week Cough, fatigue and generalized weakness may persist

Acquired through respiratory droplets Attaches via hemagglutinin spikes Induces phagocytosis and replicates inside cell

Mature viruses bud from host cell Infected cells die and slough off Destroys muco-ciliary escalator Host immunity quickly controls viral spread

New strains due to hemagglutinin and neuraminidase mutations Antigenic drift and antigenic shift Avian flu (H5N1) Swine flu (H1N1)

Epidemiology Outbreaks occur every year About 200,000 cases with up to 40,000 deaths Pandemics have higher than normal morbidity 1918-19 infected ½ the world population with 40 million deaths

Critical Swine Flu prevention tip: Don't DO this!

Prevention Treatment Vaccine New vaccine required every year Antiviral medications amantidine and rimantidine resistance common Inhaled zanamivir mist or oral oseltamivir must be taken with in 48 hours No aspirin for children!

Respiratory Syncytial Virus Infection Most common childhood respiratory disease Leading respiratory killer of infants Pathogen Respiratory syncytial virus (RSV) Enveloped, -ssRNA Paramyxovirus

Signs and symptoms Fever, runny nose, and coughing Wheezing and difficulty breathing may occur Dusky skin tone Leading cause of bronchiolitis in children under one Some children develop croup May lead to pneumonia if alveoli become involved

Epidemiology Transmission occurs via respiratory droplet Highly contagious Syncytia help viruses evade immune system Great risk of secondary infection

Prevention Treatment No vaccine Aseptic technique Isolation of infected individuals Treatment Typically only supportive care Ribavirin in extreme cases No Aspirin!

Pneumocystis Pneumonia (PCP) Causative Agent Pneumocystis jiroveci Opportunistic fungus Obligate parasite Normal respiratory flora for many

Signs and Symptoms: Difficulty breathing; mild anemia; hypoxia; and fever Non-productive cough in some cases In rare cases, extra pulmonary lesions develop in lymph nodes, spleen, liver and bone marrow

Acquired through respiratory droplets In healthy individuals usually no symptoms Life long immunity is conferred Some may remain carriers for life Fungus multiplies rapidly in immunocompromised patients and extensively colonizes lungs Causes substantial damage

Epidemiology Worldwide distribution 75% of healthy children exposed by age five Based on presence of antibodies Disease limited to immunocompromised individuals One of the diagnostic diseases of AIDS

Prevention Treatment Virtually impossible due to ubiquitous nature oral or IV TMP-SMX (combination of trimethoprim and sulfamethoxazole)