Communicable Diseases (Chapter 7) - PDF

Chapter 7 Communicable Dieseases INTERNATIONAL MEDICAL SCHOOL  Table of contents 01 02 AIDS & HIV Dengue Fever and Hemorrhagic Dengue Fever 03 04 01...

Chapter 7 Communicable Dieseases INTERNATIONAL MEDICAL SCHOOL  Table of contents 01 02 AIDS & HIV Dengue Fever and Hemorrhagic Dengue Fever 03 04 01 05 Tuberculosis Malaria Candidiasis  DEFINITION Any of many diseases or illness : ○ Cause by pathogenic organisms. ○ Bacteria, viruses, fungi or protozoa ○ Also known as communicable disease ○ Can be transfer or transmitted from person to person or from organism to organism. MODES OF TRANSMISSION skin Contact Direct Direct physical contact Contact Indirect Touches surface containing pathogen Droplet Via coughing or Sneezing From particle in the air (dust) Air-borne Food - borne – from food source Non-contact Vehicle Water - borne – from water source Vector-borne By insect or animals vector  BASIC TERMINOLOGY Unexpected increase in the Disease outbreak that is When disease’s growth is number of disease cases in consistently present but exponential. spread all a specific geographical limited to a particular around the world area.Usually temporarily. region. Ex : Covid 19, HIV Ex : Yellow fever, smallpox, Ex : Malaria measles, and polio in american region Epidemic Endemic Pandemic  Vaccine  It is a biological preparation in which to trigger immune response to fight with the disease.  Main goal : To stimulate production of antibody to naturally fight with the disease.  However, the mechanism of action (MoA) of vaccines are different depending on types of vaccine https://www.infosihat.gov.my/images/media_sihat/lain_lain/vaksin/mobile/index.html https://vaccine-safety-training.org/types-of-vaccine.html  Whole Pathogen Vaccine Viral Subunit Vectored vaccine Vaccine types Nucleic acid Toxoid vaccine vaccine  01 ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)  ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS) -AIDS Late stage of HIV infection that occurs when the body’s immune system is badly CCD4) damaged because of the virus. T Caused by HIV virus (commonly HIV -1 virus) cytotoxic Someone is considered to have AIDS if : 2 &y of Lymphocytes (T, B) ○ The number of their CD4 cells falls below 200 cells/ml3 of blood. (In someone with a healthy immune system, CD4 counts are between 500 and 1,600 cells/ml3) ○ They develop one or more opportunistic infections regardless of their CD4 count. ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS) - HIV Please take note, AIDS is definitely caused by HIV. However, HIV infection doesn’t mean that person will get AIDS. Statistics: 37.6 million people are living with HIV infection (End of 2020) - WHO 670,000 died in 2020 HIV causative agent: retrovirus. Consist of 2 types : HIV - type 1 - most common in sub-Saharan Africa and throughout the world HIV - type 2 - most often found in West Central Africa, parts of Europe and India. No wad to drow it ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)- HIV * Life Cycle of HIV HIV binds to a specific type of CD4 receptor on the surface of the CD4 cell. HIV fuse with the host cell (CD4) and release its genetic material into the cell. An enzyme, reverse transcriptase changes the genetic material of the virus to DNA, so it can be integrated into the host DNA. The virus new genetic material enters the nucleus of the CD4 cell and uses an enzyme, integrase to integrate itself into its own genetic material, where it now ‘hides’ and stays inactive for several years. Now HIV DNA is known as provirus. Transcription translation DNARNA > - Protein + (Hir) ↑ so they mix  Hir so ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)- HIV When the host cell becomes activated, the virus uses host’s own enzymes to create more of its genetic-which allows it to make longer proteins. A special enzyme, protease cuts the long HIV proteins into individual proteins. When these come together with the virus’s genetic material, a new virus has assembled. At this stage, the virus pushes itself out of the host cell, taking with it part of the membrane of the cell. This outer part covers the virus and contains all of the structures necessary to bind to a new CD4 cell and begin the process again. not detayled no need Kaposi’s Sarcoma Microplate ELISA for HIV antibody: coloured wells indicate reactivity HIV Rapid Test  ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS) Laboratory Diagnosis: Screening Tests: ○ ELISA/Rapid Assay to detect the antibodies– are the most frequently used screening assay. The sensitivity and specificity approaches 100%, but false positive and negative reactions may occur. Confirmatory Test: ○ Western Blot Test.- Gold standard for serological diagnosis to detect the antibodies. However, its sensitivity is lower than screening ELISA Other tests: ○ Absolute CD4 lymphocyte count ○ HIV viral Load  ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS) Treatment and prevention: Anti-retroviral drugs (ART) are used to suppress/slow down the replication of the virus. NOT cure. Prevention includes: ○ Wearing Condom (Practicing safe sex) ○ Elimination of mother-to-child transmission of HIV. ○ Avoid sharing needle/equipment’s ○ Blood transfusion - Make sure blood is safe  02 DENGUE FEVER  DENGUE FEVER Mosquito-borne viral infection, found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas. Caused by a virus called Dengue Virus (DENV), which belongs to genus (flavivirus) and family (flaviviridae). Have 4 serotypes: 1-4. Incubation period: 4-10 days Transmitted by mosquito ( Aedes aegypti or Aedes albopictus) Also a vector for Zika virus, chikugunya, yellow fever (flavivirus) Types of Dengue Fever Dengue Classical Dengue Shock dengue Hemorrhagic syndrome fever fever (DHF) (DSS) DENGUE FEVER- LABORATORY DIAGNOSIS Serology Molecular diagnosis Culture antigen (NS1) (NAAT (RT-PCR) antibody (ELISA) (Gold standard)  DENGUE FEVER- MEDICATION/ PREVENTION There are no specific medications to treat a dengue infection. Prevention the most important step, and prevention means avoiding mosquito bites. If a clinical diagnosis is made early, a health care provider can effectively treat DHF using fluid replacement therapy. To alleviate the signs and symptoms. Vaccine is available  03 TUBERCULOSIS  TUBERCULOSIS Causative agents Micro M. tuberculosis complex: M. bovis M. africanum (A significant cause of tuberculosis in parts of Africa) M. microti M. caprae M. pinnipedii M. canetti and M. mungi  TUBERCULOSIS - TRANSMISSION blood orgin Pulmonary TB (Inhalation), GIT (Ingestion), Other organs (Hematogenous/). Airborne, infectious aerosol droplets 0.5 to 5 µm in diameter. A single sneeze can release up to 40,000 droplets. Each one of these droplets may transmit the disease, since the infectious dose of tuberculosis is very low (Inhaling < 10 bacteria may cause an infection).  TUBERCULOSIS – SYMPTOMS AND SIGNS Majority of infections (about 90%) involves the lungs (Pulmonary TB). The symptoms include fever, chills, prolonged cough producing sputum, haemoptysis, night sweats, appetite loss, weight loss, and fatigue. Finger clubbing may also occur.  TUBERCULOSIS – LABORATORY DIAGNOSIS Tuberculin skin test (Mantoux test) Nucleic analysis – PCR and hybridization ○ RNA, DNA Culture media (often requires more than 8 weeks because of 22-hour ○ Lowenstein-Jensen ○ Middlebrook 7H10 ○ Ogawa M. tuberculosis in a sputum sample M. tuberculosis on Lowenstein-Jensen  TUBERCULOSIS – TREATMENT Anti-TB drugs ( First line drugs): ○ Isoniazid ○ Ethambutol ○ Rifampicin ○ Pyrazinamide ○ Streptomycin (previously) Treatment regimens vary between countries, but a 9-month course of isoniazid and Rifampicin has been used with good success. Multiple-Drug-Resistant M. tuberculosis (MDR) - resistant at least to isoniazid & Rifampicin. Proceed with second line drugs ( Fluoroquinolones)  TUBERCULOSIS – VACCINE Bacillus Calmette-Guérin (or Bacille Calmette-Guérin, BCG) Prepared from a strain of the attenuated (weakened) live Mycobacterium bovis (Bovine mycobacterium), that has lost its virulence in humans by being specially subcultured (230 passages) in an artificial medium for 13 years.  04 MALARIA  MALARIA An acute febrile illness caused by Plasmodium parasites. Infection of red blood cells Transmission by bites of infected female Anopheles mosquitoes. Incubation period 10-14 days in average Learn only one P. falciparum Found worldwide Most prevalent on the African continent and responsible for the majority of malaria deaths P. vivax Found in Asia, Latin America and some part of Africa P. ovale Found mostly in Africa (West) P. malariae Found in South America, Asia and Africa P. knowlesi Parasites of monkeys in South-East Asia  MALARIA- LIFE CYCLE During a blood meal, an infected female Anopheles mosquito injects thousands of malarial sporozoites, which rapidly enter hepatocytes. Reproduction by asexual fission (tissue schizogony) takes place to form a pre-erythrocytic schizont. This part of the life-cycle produces no symptoms. After a period of time, thousands of merozoites are released into the blood stream to penetrate erythrocytes. The clinical symptoms begin after the rupture of the mature schizont-infected erythrocytes, releasing the merozoites and toxic products of the parasite’s metabolism into the blood - resulting in an increase in body temperature, sometimes resulting in periodicity of fever. Most merozoites undergo blood schizogony within erythrocytes to form trophozoites, which rupture to release new merozoites. Some merozoites mature within erythrocytes into sexual forms called gametocytes, which reproduce sexually if they are ingested by a mosquito. If left untreated, the parasite counts in a malaria patient keep increasing every 24, 48 or 72 hours, depending on the Plasmodium species.  MALARIA- SYMPTOMS Uncomplicated malaria Symptomatic malaria without signs of severity or evidence (clinical/ laboratory) of vital organ dysfunction. Fever pattern: Cold stage: sensation of cold and shivering Hot stage: fever, headaches, vomiting, seizure (in young children) Sweating stage: sweats, return to normal temperature, tiredness Severe and complicated malaria Coma (cerebral malaria), metabolic acidosis, severe anaemia, hypoglycaemia, acute renal failure or acute pulmonary oedema  MALARIA- LABORATORY DIAGNOSIS Blood film for malaria parasite (BFMP) Rapid diagnostic test Serology test ○ PCR ○ ELISA Blood test ○ Full blood count (FBC) ○ Blood urea serum electrolytes (BUSE) ○ C-reactive protein ○ Liver profile ○ Glucose MALARIA- LABORATORY DIAGNOSIS  MALARIA- TREATMENT Artemisinin Combination Therapy (ACT) ○ Arthemether (Riamet) ○ Artesunate + Mefloquine (ASMQ 25/55) Antipyeretics Antiemetics Anticonvulsants Supportive treatment for severe and complicated stage: ○ Fluid therapy ○ Blood transfusion ○ Antibiotics MALARIA- PREVENTION  05 CANDIDIASIS  CANDIDIASIS Candidiasis is a fungal infection caused by a fungus, Candida, a yeast. The most common is Candida is Candida albicans. Other types of Candida - Candida Glabrata, candida tropicalis etc Candida is normal flora of skin, mouth, throat, gut, and vagina. If this fungus overgrowth/ immunocsuppressed patient - lead to infection  CANDIDIASIS- SYMPTOMS AND SIGN White patches on the inner cheeks, tongue, roof of the mouth, and throat. Redness or soreness. Cotton-like feeling in the mouth. Loss of taste. Pain while eating or swallowing. Cracking and redness at the corners of the mouth. Whitish frothy vaginal discharge with itchiness. CANDIDIASIS- SYMPTOMS AND SIGN  CANDIDIASIS- LABORATORY DIAGNOSIS Microscopy Culture onto Sabouraud dextrose agar  CANDIDIASIS- TREATMENTS Treatment is only recommended for symptomatic individuals and depending on site of infection Drugs include : i. Fluconazole, ii. Itraconazole iii. Clotrimazole, iv. Miconazole, v. Nystatin Thank you CREDITS: This presentation template was created by Slidesgo, including icons by Flaticon and infographics & images by Freepik