Public Health - Respiratory Tract Transmitted Infection Lecture Notes PDF

Public Health Respiratory Tract Transmitted Infection Prof. Mona I. Shaaban (Faculty of Pharmacy, Mansoura University) Lecture 3  Airborne transmitted Disease...

Public Health Respiratory Tract Transmitted Infection Prof. Mona I. Shaaban (Faculty of Pharmacy, Mansoura University) Lecture 3  Airborne transmitted Diseases  An airborne disorder is any disease that is caused by a microorganism that is transmitted through the air.  Airborne diseases are caused by a variety of pathogens, including bacteria, viruses, and fungi. Methods of transmission  Coughing, Sneezing or talking  Through close personal contact  Fine mist, dust, or liquids.  Droplets  Aerosols, the infectious agents are suspended in air over long distance and time  Symptoms common cold or the typical flu. Symptoms would include:  Coughing  Sneezing  Sinus congestion  Sore throat and fatigue. Airborne precautions:  Use of appropriate personal protective equipment, such as particulate filter respirators (PFRs), N95.  Patient placement (e.g. use of negative pressure rooms).  Minimizing patient movement. particulate filter respirators PFR According National Institute for Occupational Safety and Health, (NIOSH) - N95 Respirator N” means Not resistant to oil. filtering efficacy non-oily particles (such as acid, dust, microorganism, etc.) is attains 95 % of particles sized 0.1–0.3 μm -KN95 Respirator 80%–95 % efficient of particles < 0.3 μm , china - R-type (Resistant to oil) - P-type (Strongly Resistant to oil/Oil Proof) R99, Their filtering power is at least 99 % of particles sized 0.1–0.3 μm R100, Their filtering power is at least 99.7 % of particles sized 0.1–0.3 μm P99, Their filtering power is at least 99 % of particles sized 0.1–0.3 μm P100. Their filtering power is at least 99.7 % of particles sized 0.1–0.3 μm Viral airborne pathogens Bacterial airborne pathogens  Measles  Tuberculosis  Mumps  Diphtheria  Chickenpox  Pertussis  Smallpox  Streptococcal Diseases  Influenza  Streptococcus pneumonia  Avian Influenza  Anthrax  Swine Flu  SARS  COVID-19 1-Measles (Rebeula) Causative agent: Measles virus , -ve strand enveloped RNA virus Reservoir: Man Mode of infection:  1. Direct droplet infection (sneeze- or cough)  2. Indirect droplet through contaminated article. Symptoms  Fever, cough, runny nose, and conjunctivitis.  Otitis media and Pneumonia  Diarrhea  Koplik spots (blue-white spots with a red halo) in the mouth and throat.  Generalized macular rash (non pruritic small red or pink spots), beginning at head and spread to lower extremities. Blue-white spots with a red halo Subacute sclerosing panencephalitis (SSPE) It is a rare chronic measles infection of children that appears 2 to 10 years after measles infection and produces neurologic disease characterized by an insidious onset of personality change, progressive intellectual deterioration, and both motor and autonomic nervous system dysfunctions  Diagnosis  Clinical manifestations; Koplik spots  ELISA assay for measles antibodies (Ig-M)  RT-PCR  Treatment  Antipyretic such as paracetamol  Antibiotic to manage 2nd bacterial infection, such as Amoxicillin/clavulanic acid OR Ceftriaxone and Cloxacillin (sever pneumonia).  Vitamin A, retinol to prevent vit A depilation and prevent Xerophthalmia and blindness.  ORS oral rehydrating solutions for diarrhea  Nystatin for secondary fungal infection  Prevention  A live, attenuated measles vaccine, MR: measles and rubella MMR: measles, mumps and rubella; MMRV: measles, mumps, rubella and varicella.  MMR, two doses, the first at 12 to 18 months , the second at 4 to 6 years (MMRV).  Post exposure prevention  Immunoglobulin (IG) within six days of exposure.  2-Mumps Causative agent: Mumps virus,- ve strand RNA virus Reservoir: man Transmission  Respiratory droplets and saliva Clinical significance  Swelling and tenderness of salivary glands, (parotid glands).  Low fever  Complications; deafness, meningitis, encephalitis, and inflammation of the epididymis and testes (orchitis) leading to sterility Laboratory diagnosis Serologic tests detect antiviral antibody in the blood., IgM, RT-PCR Treatment and prevention  No antiviral drugs are available for mumps  MMR vaccine (LAV of measles, mumps and rubella given at 12/18 months).  3-Chickenpox Causative agent: Chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus (VZV ). Transmission:  Spread through coughing or sneezing  Through direct contact with secretions from the rash.  Incubation period 10 to 21 days Symptoms: – Fever – Lesions on the chest, back, head and ears, and proximal extremities. Involvement of mucous membranes – Skin lesions are pruritic (itchy), fluid-filled vesicles and then crust over. Diagnosis – LFA of (IgM) – Previous infection and subsequent immunity (IgG) Treatment - There is no specific treatment. - Acyclovir; In immunocompromised patients, and sever cases - Symptomatic treatment - Acetaminophen for fever, NOT Aspirin (it causes Reye syndrome; an acute encephalopathy accompanied by fatty liver). - Calamine lotion to relieve itching. - Antihistamines such as diphenhydramine for itching Prevention: 1) Hygiene measures – Isolating affected individuals, – The chickenpox virus (VZV) is susceptible to disinfectants, chlorine – VZV is sensitive to heat and detergents. 2) Varicella vaccine Varivax®  Contains only chickenpox vaccine.  It is use in people 12 months of age or older.  Two doses of chickenpox vaccine at 12-15 months old and age 4-6 years.  People 13 years of age and older who have never had chickenpox or received chickenpox vaccine should get two doses, 28 days apart ProQuad®  Contains a combination of measles, mumps, rubella, and varicella (chickenpox) vaccines, which is also called MMRV.  Is licensed for use in children 12 months through 12 years. Recurrent infection (herpes zoster, or shingles):  The reactivation, multiplication and spread of virus among the ganglion. Symptoms - The pre-eruptive phase, preherpetic neuralgia stage, dermatomes, Headache, tiredness, sensitivity to light, and fever. - The acute eruptive phase (2-4 weeks) with appear of lesions, macules and develop into clusters of fluid-filled blisters and crust over. With Itchy, Pain, burning, numbness or tingling  Rash develops wraps around one side of torso, one eye or the neck or face.  Ramzy Hunt Syndrome a vesicular rash on the ear, in the oral mucosa accompanied by acute peripheral facial nerve paralysis, and Other cranial nerves are involved  Complications  long-term nerve pain called post herpetic neuralgia, ( PHN) which persist after relief of blisters.  Reactivation increases with Age (most common above 50 years) weakened immune system Emotional stress Diagnosis -Direct fluorescent antibody (DFA) testing of vesicular fluid or a corneal lesion -PCR  Treatment -Most cases are self-limiting within 2 to 3 weeks. - sever cases; Oral acyclovir, Valacyclovir. - Analgesics, Corticosteroids, Adjuvant analgesics: gabapentin or pregabalin -Symptomatic treatment, applying calamine lotion - Varicella-zoster immune globulin (VZIG)  Post-herpetic neuralgia  Topical lidocaine patch 5%, gabapentin, pregabalin, opioids, tricyclic antidepressants (TCAs), tramadol and topical capsaicin cream and patch.  Prevention  Recombinant zoster vaccine (RZV, Shingrix), for older adults, two doses  Varivax for children  4-Small pox Contagious infectious disease Causative agent: Variola virus Reservoir: human Mode of transmission: 1. Direct droplet 2. Prolonged contact with infected person Contact with infected body fluids or contaminated objects Clinical picture: Severe, very high fever and large rash (Not temporary) Prevention: Due to the effective vaccination live attenuated vaccinia virus (cowpox virus), no cases smallpox have recorded since 1977  5-Influenza  Cause; influenza virus, with 8 RNA segments.  Classified as types A, B, C, and D depending on the antigenicity of their inner proteins (Influenza A and B cause seasonal epidemics in human). - Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). - There are 18 different hemagglutinin subtypes H and 11 different neuraminidase subtypes N). - Influenza showed variation in the antigenic characters due to: antigenic drift and antigenic shift - Genetic Drifts— Small changes in genetic material called point-mutations and still recognized by antibodies (cross protection) - If the mutation affect the HA to a degree NOT recognized by AB (antigenic drift) - This is the cause of the repeated influenza infection - This is Also the cause of the annual flu vaccine. - Genetic Shifts result from reassortment of genetic material between different strains of influenza viruses. This can involve the creation of new H and N proteins on the virus coat. with limited immune recognition by humans. reassortment may also result in a very virulent new strain (causing Pandemic flu). Methods of transmission  Respiratory droplets (Coughing, Sneezing, Droplets on objects) Symptoms  Nonproductive Cough and congestion, Fever, Headache, Sore throat  Body Aches, General malaise Complications;  Superinfection. can lead to bacterial pneumonia  Direct rapid progression. Less commonly, progression of the viral infection can lead to viral pneumonia with asphyxia.  Neurological (eg encephalitis), cardiac (eg myocarditis, pericarditis), muscle (eg rhadomyolysis) or multi-organ failure Diagnosis  Rapid test, detection viral antigens in respiratory tract secretions  Detection of viral RNA by reverse transcription polymerase chain reaction Treatment Symptomatic treatment  First-generation antiviral agents; amantadine and rimantadine. inhibit viral uncoating and effective against influenza A  Second-generation antiviral agents zanamivir, oseltamivir , baloxavir and peramivir inhibit viral neuraminidase and inhibit viral release and effective against influenza A and B. Adjunctive therapies, macrolides passive immune therapy  Targeted individuals for vaccination Protection  Vaccination; - Flu shot, inactivated or killed viral vaccine. - Influenza virus vaccine trivalent (2 influenza A and 1 influenza B) Influenza virus vaccine quadrivalent (2 influenza A strains and 2 influenza B strains) - FluMist, life attenuated, nasal spray  Administered yearly (contains the specific subtypes of influenza)  Risk groups; >50 years old, Diabetic, Live or work in a nursing home Immunocompromised, Chronic heart, lung, or kidney disease, >3 months pregnant during flu season).  Use proper care measurements in contact with patients having flu  Disinfect surfaces  Keep healthy during the flu season  Avian Influenza Influenza virus can infect birds and humans. It is Type A influenza Three Type A viruses and each have 9 subtypes  H5: can be high or low pathogenic; can cause severe illness or death.  H7: can be high or low pathogenic; infections are rare, and symptoms are mild.  H9: low pathogenic; very rare in humans. Incidents of Avian Influenza - In 1997, human infections with A(H5N1) viruses were reported during an outbreak in poultry in Hong Kong SAR, China. - In 2013, human infections with A(H7N9) viruses were reported for the first time in , China. - Since 2014, sporadic human infections with avian influenza A(H5N6) viruses have been reported almost exclusively from China.  Transmission  Contact with infected poultry or contaminated surfaces.  No documented cases of sustained human to human transmission.  Symptoms  Same as typical flu-like symptoms  Conjunctivitis  Pneumonia  Severe respiratory distress  Death; systemic dissemination, alveolar flooding, Na+ channel blockage, and cytokine storm  Prevention - Avoid the contact with the live or dead birds - Hand hygiene - Good food handling  Swine flu -The World Health Organization (WHO) declared the H1N1 flu to be a pandemic in 2009, The scientific name for the swine flu virus is A/H1N1pdm09 - In August 2010, WHO declared the pandemic over. -It causes flu in swine and transmitted to human -It can spread from person to person -Morbidity rate 1-4% Symptoms of novel H1N1 flu in people are similar to those associated with seasonal flu.  Fever, Cough, Sore throat  Runny or stuffy nose  Body aches  Headache  Chills  Fatigue  In addition, vomiting (25%) and diarrhea (25%) have been reported. (Higher rate than for seasonal flu.)  Sever cases; Pneumonia, ARDS, sepsis, and death  Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury that allows fluid to leak into the lungs. Breathing becomes difficult and oxygen cannot get into the body.  Treatment Adamantanes are not active against influenza B strains and there is widespread resistance among influenza A strains.  Avian influenza viruses A(H5N1) are susceptible to M2 blockers NAIs  Tamiflu (oseltamivir) 75 mg twice daily for 5-10 days according to the severity of infection (Avian influenza A(H5N1) and A(H7N9)  Alpivab (peramivir)  Relenza (zanamivir) Zanamivir (intravenous formulation)  Methods of transmission  Primarily through respiratory droplets o Coughing, Sneezing o Touching respiratory droplets on yourself, another person, or an object, then touching mucus membranes (e.g., mouth, nose, eyes) without washing hands.  Treatment by Antivirals- Oseltamivir  Treatment is 75 mg twice a day for 5 days.  Prophylaxis is 75 mg once a day for 7 days after last exposure.   6- Corona Cause; Corona viruses are positive-strand RNA viruses named for the crown like spikes on their surface. There are four main subtypes of coronaviruses: alpha, beta, gamma, and delta. Coronavirus - A large family of viruses that cause illness ranging from the common cold to more severe diseases such as 1-Middle East Respiratory Syndrome (MERS-CoV) 2- Severe Acute Respiratory Syndrome (SARS-CoV). 3-A novel coronavirus (COVID-19) Symptoms Common signs of infection include: o Respiratory symptoms o Fever o Cough o Shortness of breath and breathing difficulties In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, renal failure and even death.  SARS: Severe Acute Respiratory Syndrome - SARS-CoV was first recognized in China in 2002, where it infected 8,098 people; it killed 774 worldwide in about a year. - Since 2004 there have been no known cases of SARS-CoV. - Amino acid substitution within the receptor-binding domain of the SARS membrane spike protein was the reason for reduced virulence of SARS-CoV infections in 2004 Transmission Close contact with respiratory secretions (person to person) Symptoms of SARS Fever, Cough, Pneumonia, Respiratory distress, Chills and shaking Cough, usually starts 2 to 7 days after other symptoms Headache, Muscle aches, Tiredness Less common symptoms include:Diarrhea, Nausea and vomiting Complications include: Respiratory failure  Treatment Liver failure  Lopinavir-ritonavir Heart failure  Remdesivir Kidney problems  Middle East respiratory syndrome (MERS) Cause; beta coronavirus MERS-CoV. Epidemiology; It was first reported in Saudi Arabia in 2012 In 2015, an individual traveling from the Middle East sparked an outbreak in South Korea that eventually resulted in about 35 deaths Transmission - Transmitted from person to person, - MERS is also zoonotic, being transmitted to humans from dromedary camels. Symptoms - Most people infected with MERS-CoV develop severe acute respiratory illness, including fever, cough, and shortness of breath 4 to 5 days after exposure. - Many of the infected also develop diarrhea - Severe cases are associated with pneumonia and renal failure - MERS has a 30 to 40% mortality rate. Diagnosis: RT-PCR and serology Prevention - Respiratory protection - Hand hygiene  COVID-2019 virus COVID-19 Epidemiologic Patterns Epidemiology - Age distribution: 78% of cases aged 30-69 - Sex distribution: 51.4% male, 48.6% female - Case severity:  Mild: 81%  Severe 14%  Critical: 5% Mortality highest amongst individuals >80 years of age Modes of Transmission  Close contact (e.g. in a household workplace, or health care centers).  Hand-to-mucus-membrane contact  Respiratory droplets ( coughs or talks ).  Airborne –intubation  T-zone: eyes, nose, mouth vulnerable  Viable for 3 days on solids (plastics, porcelain, steel); ~24 hours cardboard, dependent also on temperature/humidity; 3 hours if aerosolized  Symptoms  Incubation period 1-27 days  -Week 1: Fever (77-98%) (intermittent or persistent), Fatigue/Malaise (11- 52%), Dry cough (46-82%), dyspnea (3-31%); Less common: Sputum, Myalgia, Headache, Sore throat, Diarrhea, Nausea/Vomiting, Nasal congestion (4%), Hemoptysis (1%)  - Week 2; 15-20% develop severe dyspnea due to viral pneumonia  - Hospitalization, supportive care, oxygen  - Week 2-3: Of hospitalized patients, 1/3 ultimately need ICU care, needing intubation (i.e. ~5% of total diagnosed cases need ICU), hypoxia to frank ARDS, Cytokine Storm, dysfunction of air exchange, organ damage, pneumonia, cardiac injury, thromboembolism, edema and Multi-organ failure  Late stage sudden cardiomyopathy/viral myocarditis, cardiac shock Standard recommendations to reduce exposure to and transmission of a range of illnesses includes: o Washing hands with soap and water or using alcohol-based o Covering mouth and nose when coughing and sneezing, o Avoid touching eyes, nose and mouth : hands touch many surfaces which could be contaminated by the viruses that are discharged from an infected person and staying for a while on the surfaces. o Adopting safe food practices o Avoiding close contact, when possible, with anyone showing symptoms of respiratory illness such as coughing and sneezing. o Maintain social distancing: Maintain at least 1 meter (3 feet) distance between yourself and anyone who is coughing or sneezing. o Practice self-quarantine and seek early medical care: Stay home if you feel unwell. If you have a fever, cough and difficulty breathing, seek medical attention as early as possible. Follow the directions of your local health authority. Diagnosis CBC (leukopenia, 30-45%, and lymphocytopenia in 85%) Chest X rays CT scan (sensitivity 95%), Bilateral diffuse ground glass opacities, multifocal patchy consolidation, RT-PCR Rapid test Treatment & Protection 1-Antiviral drugs inhibits viral replication , such - Remdesivir (IV, 200 mg on day one and 100 mg on days two through 10 subsequently, Remdesivir inhibits viral replication by prematurely terminating RNA transcription through binding to the viral RNA-dependent RNA polymerase - Paxlovid Paxlovid is a 3CL protease inhibitor that works by blocking an enzyme required for viral protein synthesis - Molnupiravir, inserting mutations into the viral genome during replication 2-Anti-inflammatory drugs, for controlling inflammation and immune response caused by viral infection, such as - interleukin inhibitors, -lactoferrin, colchicine -Methylprednisolone (dexamethasone is recommended by the IDSA and NIH panels for patients with severe COVID-19 who required supplemental oxygen. The guidelines recommend against using glucocorticoids in non-hospitalized COVID-19 individuals who do not have hypoxemia and do not require extra oxygen), 3-Adjunct drugs, such as antibiotics, anticoagulants, and vitamins, for reducing the risk of viral complications Prevention  Adenoviruses Transmission:  Respiratory route  Fecal–oral route  Virus contaminated hands, ophthalmologic instruments, or swimming pools Clinical significance Common cold or flu-like symptoms, fever, sore throat Acute bronchitis (inflammation of the airways of the lungs, sometimes called a “chest cold”) Pneumonia (infection of the lungs) Acute gastroenteritis (causing diarrhea, vomiting, nausea and stomach pain) Conjunctivitis.  Less common symptoms of adenovirus infection include  bladder inflammation or infection  neurologic disease Treatment  No approved antiviral drug  Symptomatic treatment  Rhinoviruses (Common Cold)  Disease: Common cold.  Transmission: Aerosol droplet and hand to nose contact.  Pathogenesis: infection of mucosa of the upper respiratory tract and conjunctiva, it does not infect lower respiratory tract.  It causes sneezing, nasal discharge, sore throat, cough, headache and chills.  Prevention and treatment: No vaccination due to large number of serotypes.  Treatment: Symptomatic treatment.  Pharmacologic treatment  NSAIDs and antihistamines to relieves nasal obstruction.  Oral decongestants (pseudoephedrine) and topical decongestants (oxymetazoline and phenylephrine)  First-generation antihistamines, topical anticholinergics, and ipratropium bromide reduce rhinorrhea by 25-35%.  Second-generation or nonsedating antihistamines appear to have no effect on common cold symptoms.  Corticosteroids have no impact on cold symptoms and may increase viral replication.  In adults, oral zinc reduced duration of illness when high doses (at least 75 mg of elemental zinc per day) were used and when taken within 24 hours of onset of common cold symptoms  Zinc has been associated with faster resolution of nasal congestion, nasal drainage, and sore throat, as well as improvement of cough (in terms of cough score).  Respiratory Syncytial virus Transmission: respiratory droplets Clinical findings: Include runny nose, coughing, sneezing, fever, decreased appetite, and wheezing. and breathing difficulties -It is very common cause of bronchitis in infants