Emerging and Re-emerging Infectious Diseases PDF

Emerging and Re-emerging Infectious Diseases By Raghda Elsayed Farag Prof. Tropical Medicine Learning outcomes To define emerging and re-emerging infectious disease To know factors influencing emerging and re-emerging infections To take an overview on examples...

Emerging and Re-emerging Infectious Diseases By Raghda Elsayed Farag Prof. Tropical Medicine Learning outcomes To define emerging and re-emerging infectious disease To know factors influencing emerging and re-emerging infections To take an overview on examples of some emerging diseases e.g. Avian Swine Seasonal flu Zica virus Monkey pox Case Scenario Sally, a 24-year old female with 36 ws duration of pregnancy, presents to the primary care clinic with complaints of fever, cough, and difficulty breathing for the past five days. She reports long contact with a dead chicken infected with bird flu Review of history taking General The patient reports fever, fatigue, and malaise. Respiratory The patient experiences a dry cough that is persistent and worsens over time. She complains of shortness of breath, especially with exertion. Constitutional The patient reports fatigue, body aches, and headache. Gastrointestinal The patient mentions a loss of appetite and occasional nausea. Musculoskeletal The patient reports generalized body aches. Investigation history - WBCs 5.000, Lymphocytes 11% -platletes 80.000 Lab. - Liver enzymes: AST 60/38, ALT, 120/40 - Inflammatory markers (C-reactive protein: 48, ferritin: 890) Physical Examination 1. Blood pressure: 120/80 mmHg 2. Heart rate: 90 beats per minute Vital Signs 3. Respiratory rate: 26 breaths per minute 4. Temperature: 38.9°C (102°F) 5. Po2 94% The patient demonstrates tachypnea. Respiratory Auscultation reveals decreased breath sounds in the lower lung fields and occasional crackles. Regular rate and rhythm, with no murmurs or abnormal Cardiovascular heart sounds. Gastrointestinal No significant findings upon abdominal examination. The patient is alert and oriented, with no focal Neurological neurological deficits. Bilateral ground glass consolidation at peripheral lung Radiological zones  Emerging infections: Infectious diseases that have newly appeared in a population or have existed but are rapidly increasing in incidence or geographic range (COVID-19, Avian flue, Swine flue, Zika virus, HIV) Re-emerging infections: The reappearance of a previously known infection after a period of disappearance or decline in incidence (TB, Cholera,polio, malaria). Factors affecting emerging infections Host factors: Human behavior Human susceptibility to infection (immunosuppression) International travel & commerce Pathogen factors: High frequency of mutations Co-evolution and pathogenicity Development of resistance to drugs Environmental factors: Changing climate and eco-systems Technology and Industry N1H1 Flue (Seasonal Flu) It is typically refers to influenza A virus. Transmitted through direct or indirect contact with infected person. In 1918, Spanish Influenza Flu was the first File:1918 flu outbreak2.jpg known pandemic and estimated to cause from 60 to 80 Million Deaths Worldwide. First Wave (March 1918) Mild Seasonal Flu Virus Second Deadly Wave ( Summer/Fall of 1918) Virus Mutated to a More Deadly Strain So majority of the fatalities was In the Second Wave Clinical Presentation - Common symptoms of the flu include a fever, aching muscles, chills and headache. - Other symptoms include: Headache. Dry, persistent cough. Shortness of breath. Tiredness and weakness. Runny or stuffy nose (much less than common cold). Sore throat. Retro-orbital pain. Vomiting and diarrhea are more common in children than in adults. Clinical course Days 1–3: Sudden onset of fever, headache, muscle pain and weakness, dry cough, sore throat and sometimes a stuffy nose. Day 4: Fever and muscle aches decrease. Hoarse, dry or sore throat, cough and possible mild chest discomfort. Days 5-7: Flu symptoms begin to decrease.... Day 8 and Beyond: Symptoms are continuing to improve and resolve. How can you differentiate flu from common cold The flu less likely to present with a runny nose, sneezing and sore throat. Colds usually start slowly. But the flu tends to come on quickly. Flu usually is much worse. Prevention Seasonal influenza vaccine every year is the best way. Treatment Drink plenty of liquids. to prevent dehydration. Rest. Consider pain relievers. Use acetaminophen or ibuprofen In severe infection or are at higher risk of complications, an antiviral medicine may be needed. Oseltamivir (Tamiflu) for five days AVIAN (BIRD) FLU H5N1. MICROBIOLOGY Avian influenza typically refers to influenza A virus. Most well-known HPAI (highly pathogenic avian influenza) strain is H5N1. EPIDEMIOLOGY Human infections first reported in 1997 in Hong Kong. Since 2003, more than 700 human cases have been reported to the WHO. Viruses are easily transmissible and fetal among birds. Rarely cause seasonal flue infection to human. TRANSMISSION 1. Direct or indirect contact with infected live or dead poultry. 2. Contact with avian influenza A virus-contaminated environments. 3. Human-to-human transmission occurs ONLY with mutations. SYMPTOMS Incubation period (3-7 days) Malaise High grade fever >38C Headache Cough / sore throat Tiredness Runny / blocked nose Limb or joint pain Sneezing Diarrhea / vomiting / abdominal pain / chest pain / bleeding from nose and gum SWINE FLU Swine flu is caused by H1N1 influenza virus that infects the respiratory tract of pigs. H1N1 is one of several influenza virus strains that can cause seasonal flu in human. H1N1 appears to be mostly due to a combination of human influenza, swine and avian viruses 2009 swine flu pandemic is the third recent flu pandemic involving the H1N1 virus: (The first was the 1918–1920 Spanish flu pandemic; the second was the 1977 Russian flu) COMPLICATIONS Hypoxemia (dyspnea) Pneumonia Acute respiratory distress Respiratory failure Multiple organ dysfunction Secondary bacterial and fungal infections MODE OF TRANSMISSION Direct droplet transmission from cough or sneeze of an infected person. Indirectly through surfaces contaminated from an infected case. Improper handling and cooking of pork products from swine infected with H1N1 virus. SYMPTOMS COMPLICATIONS Same as avian flu Same as avian Flue Mention? Mention? DIAGNOSIS Sample 1. Nasopharyngeal aspirate / wash 2. Oropharyngeal / throat swab Tests Viral culture Reverse transcription polymerase chain reaction (RT-PCR) Rapid influenza diagnostic tests (RIDTs) TREATMENT 1. Hospitalization and isolation 2. General and supportive treatment: Monitor vital signs Maintain hydration, electrolytes, and nutrition Paracetamol for fever 3. Oseltamivir (Tamiflu) 75 mg twice daily for 5 days SEVERE ACUTE RESPIRATORY SYNDROME (SARS) DEFINITION: Severe acute respiratory syndrome (SARS) is a viral respiratory illness of zoonotic origin caused by SARS-associated coronavirus (SARS-CoV-1). Caused the 2002-2004 SARS outbreak No cases of SARS-CoV-1 have been reported worldwide since 2004 TRANSMISSION 1. Direct droplet transmission from cough or sneeze of an infected person. 2. Indirectly through surfaces contaminated from an infected case. SYMPTOMS COMPLICATION Fever, chills Dry cough Fatigue Pneumonia Headache Dyspnea Sore throat Hypoxia (fatal) Muscle pain 2ry bacterial infections Diarrhea (10-20% of patients) Multi-organ failure (GI, liver, kidney) DIAGNOSIS CT chest atyptical pneumonia or acute respiratory distress syndrome ELISA, immunuflourescence For SARS-CoV-specific antibodies PCR For virus identification TREATMENT 1. Hospital admission (isolation, close observation) 2. Treatment is supportive: Ventilator to deliver oxygen (assist breathing) Antibiotics (for pneumonia and secondary bacterial infections) High dose steroids (reduce swelling in lungs)  MIDDLE EAST RESPIRATORY SYNDROME (MERS) DEFINITION: Viral respiratory infection caused by Middle East respiratory syndrome coronavirus (MERS-CoV) belonging to the genus betacoronavirus which is distinct from SARS coronavirus and common-cold coronavirus EPIDEMIOLOGY The first case was identified in June 2012 in Jeddah, Saudi Arabia Larger outbreaks have occurred in: − South Korea in 2015 − Saudi Arabia in 2018 TRANSMISSION Humans are typically infected from camels, either during direct contact or indirectly. Human-to-human spread typically requires close contact with an infected person (healthcare or household setting), so risk to global population is considered low SYMPTOMS Range from asymptomatic disease to severe pneumonia leading to ARDS. Complications include: 1. Kidney failure 2. DIC 3. Pericarditis DIAGNOSIS 1. RT-PCR testing of blood and respiratory samples 2.  white blood cell count, especially  lymphocytes TREATMENT and PREVENTION same as SARS.  ZIKA FEVER Zika virus Zika virus is a member of virus family flaviviridae TRAMSMISSION 1. Spread by daytime-active Aedes aegypti mosquitoes 2. Sexual contact 3. Blood transfusion 4. Vertical (mother-to-child) transmission EPIDEMIOLOGY Since the 1950s, it occured sporadically from Africa to Asia. From 2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015-2016 Zika virus epidemic. SIGNS AND SYMPTOMS COMPLICATIONS Incubation period 3-14 days 1. Infection during pregnancy: Typically asymptomatic a. Pregnancy complications (fetal loss, stillbirth, and preterm birth) Mild symptoms usually last 2-7 days: b. Microcephaly + congenital 1. Low fever abnormalities in the developing fetus 2. Maculopapular rash and newborn 3. Conjunctivitis 2. Guillain-Barré syndrome 4. Muscle and joint pain 3. Neuropathy 5. Malaise / headache 4. Myelitis  Zika Rash & conjunctivitis Aedes Aegypti Anencephaly Diagnosis Molecular testing for presence of the virus: RT-PCR for ZIKV RNA Immunoassay for viral proteins Virus isolation for live virus Serological testing for presence of antibodies(ELISA) Not recommended since antibodies against Zika: − Persist for years − Cross-react with other similar viruses, including dengue A positive lab result often cannot definitively tell you if you have a current or past infection or whether it is a Zika or dengue infection  Treatment No specific treatment for Zika virus infection Fluids to prevent dehydration. Paracetamol for joint pain and fever. Monkey Box Mpox  Monkey Pox (Mpox) - Mpox is an infectious disease that can cause a painful rash, enlarged lymph nodes, fever, headache, muscle ache, back pain and low energy. - Most people fully recover, but some get very sick. - Mpox is caused by the monkeypox virus (MPXV). It is an enveloped double-stranded DNA virus of the Orthopoxvirus genus in the Poxviridae family  Epidymiology It was discovered in Denmark (1958) in monkeys kept for research. Following the eradication of smallpox in 1980 and the end of smallpox vaccination worldwide, mpox steadily emerged in central, east and west Africa. Since 2005, thousands of cases are reported in the Democratic Republic of the Congo every year. In 2017, mpox re-emerged in Nigeria and continues to spread between people across the country and in travellers to other destinations. In 2022, outbreaks of mpox occurred in refugee camps in the Republic of the Sudan. Over 120 countries have reported mpox between Jan 2022 – Aug 2024, with over 100 000 laboratory- confirmed cases reported and over 220 deaths among confirmed cases.  Transmission Mpox spreads from person to person mainly through close contact, includes skin-to-skin. It can also include being face-to-face with case which can generate infectious respiratory particles. People with multiple sexual partners are at higher risk of acquiring mpox. People can also contract mpox from contaminated objects such as clothing or linen, or through needle injuries, or tattoo. Vertical transmission during pregnancy or birth. Aquiring mpox during pregnancy can lead to loss of the pregnancy, stillbirth, death of the newborn.  Signs and symptoms Sart 1–21 days after exposure. Symptoms typically last 2–4 weeks but may last longer in someone with a weakened immune system(HIV). Common symptoms of mpox are: rash fever sore throat headache muscle aches back pain low energy swollen lymph nodes.  Differential Diagnosis: chickenpox, measles, bacterial skin infections, scabies, herpes, syphilis, other sexually transmitted infections, and medication-associated allergies. patients with mpox may also have another sexually transmitted infection at the same time, such as syphilis, HIV or herpes.  Diagnosis The preferred laboratory test for mpox is detection of viral DNA by polymerase chain reaction (PCR). The best diagnostic specimens are taken directly from the rash – skin, fluid or crusts – collected by swabbing. In the absence of skin lesions, testing can be done using swabs of the throat or anus. Antibody detection methods may not be useful as they do not distinguish between different orthopoxviruses. HIV, syphilis, testing should be offered to patients with mpox.  Treatment and vaccination The goal of treating mpox is; to take care of the rash, manage pain and prevent complications. Getting an mpox vaccine can help prevent infection (pre-exposure prophylaxis). It is recommended for people at high-risk of getting mpox, especially during an outbreak. Groups that may be at high risk of mpox include: health and care workers at risk of exposure; people in the same household or close community as someone who has mpox, including children; people who have multiple sex partners, including men who have sex with men; and sex workers of any gender and their clients.  Do stay at home wash hands often with soap and water or hand sanitizer, especially before or after touching sores; wear a mask and cover lesions when around other people until rash heals; keep skin dry and uncovered when be alone avoid touching items in shared spaces and disinfect shared spaces frequently; use saltwater rinses for sores in the mouth; take warm baths with baking soda or Epsom salts for body sores; and take over-the-counter medications for pain like paracetamol (acetaminophen) or ibuprofen.  Do not pop blisters or scratch sores, which can slow healing, spread the rash to other parts of the body, and cause sores to become infected; or shave areas with sores until scabs have healed and you have new skin underneath (this can spread the rash to other parts of the body). Q1. The following drug can be used for ttt of both swine and avian flu: a. Oseltamivir b. Tenevofir c. Sofosbuvir d. Acyclovir e. Remidisvir Q3. Example of re-emerging infection is: a. Avian flu b. Swine flu c. Cholera d. Covid-19 virus e. Seasonal flu Any Questions??!  Back to our case What is the most probable diagnosis? According to severity classification is it mild, moderate or severe? What is the risk factor? Discuss suitable drug therapy?  References & recommended readings Handbooks: Davidson, R., Brent, A., Seale, R., & Seale, Anna. (2014).Oxford handbook of tropical medicine (4th ed., Oxford medical publications). Oxford: Oxford University Press (Textbook) Manson's Tropical Diseases. Edition: 23rd. Elsevier. http://www.dpd.cdc.gov/dpdx Thank You