The document discusses key concepts related to host-pathogen relationships and the occurrence and spread of infectious diseases. It defines important terms like infection, disease, colonization, and defines the roles of the host and pathogen. It describes the chain of infection and factors that influence a host's resistance or susceptibility to disease. It also outlines common routes of entry for pathogens, signs and symptoms for different types of infections, and ways that pathogens can spread within the body and between hosts through different modes of transmission.
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community.
The most common cooperative interactions seen in microbial systems are mutually beneficial. The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.
Microbial interactions are ubiquitous, diverse, critically important in the function of any biological community.
The most common cooperative interactions seen in microbial systems are mutually beneficial. The interactions between the two populations are classified according to whether both populations and one of them benefit from the associations, or one or both populations are negatively affected.
INTRODUCTION:
The first plant virus shown to have a DNA genome and the first shown to replicate by reverse transcription.
Worldwide but only causes significantly losses locally.
It is transmitted by aphids .
Type member of the Caulimovirus genus, contains 11 species and 6 possible members.
significantly impact on plant virology and plant molecular biology.
The virus is an important source of gene regulatory elements, used exclusively in the genetic manipulation of plants.
STRUCTURE:Icosachedral with a diameter of 52Â nm built from 420 capsid protein subunits.
It contains a circular double-stranded DNA molecule of about 8.0 kB .
Dna is interrupted by sitespecific discontinuties resulting from its replication by reverse transcription.
After entering the host, the single stranded nicks in the viral DNA are repaired, forming a supercoiled molecule that binds to histones.
DNA is transcriped into a full length .
Replication
Risk Factors:The Cauliflower mosaic virus promoter (CaMV 35S) is used in most transgenic crops to activate foreign genes which have been artificially inserted into the host plant. It is inserted into transgenic plants in a form which is different from that found when it is present in its natural Brassica plant hosts. This enables it to operate in a wide range of host-organism environments which would otherwise not be possible.
Culture Collection Center National and International RinuRolly
Culture collection , Purpose of culture collection center and some famous International Culture Collection Center and National Culture Collection Centers of India .
Viruses are small, acellular particles that can replicate only in a host cell. They are obligatory intracellular parasites.They
consist of a nucleic acid genome enclosed in a protective protein shell or capsidBacteriophage is the virus that infect bacteria.Bacteriophages were discovered by Frederick Twort(1915)and Felix d'Herelle(1917).
0.1 What are viruses?
1. Origin of viruses
1.1 introduction
1.2 Theories
RNA molecules that existed before cells
cell components
micro-organisms.
1.3 Conclusion: How did viruses originate?
INTRODUCTION:
The first plant virus shown to have a DNA genome and the first shown to replicate by reverse transcription.
Worldwide but only causes significantly losses locally.
It is transmitted by aphids .
Type member of the Caulimovirus genus, contains 11 species and 6 possible members.
significantly impact on plant virology and plant molecular biology.
The virus is an important source of gene regulatory elements, used exclusively in the genetic manipulation of plants.
STRUCTURE:Icosachedral with a diameter of 52Â nm built from 420 capsid protein subunits.
It contains a circular double-stranded DNA molecule of about 8.0 kB .
Dna is interrupted by sitespecific discontinuties resulting from its replication by reverse transcription.
After entering the host, the single stranded nicks in the viral DNA are repaired, forming a supercoiled molecule that binds to histones.
DNA is transcriped into a full length .
Replication
Risk Factors:The Cauliflower mosaic virus promoter (CaMV 35S) is used in most transgenic crops to activate foreign genes which have been artificially inserted into the host plant. It is inserted into transgenic plants in a form which is different from that found when it is present in its natural Brassica plant hosts. This enables it to operate in a wide range of host-organism environments which would otherwise not be possible.
Culture Collection Center National and International RinuRolly
Culture collection , Purpose of culture collection center and some famous International Culture Collection Center and National Culture Collection Centers of India .
Viruses are small, acellular particles that can replicate only in a host cell. They are obligatory intracellular parasites.They
consist of a nucleic acid genome enclosed in a protective protein shell or capsidBacteriophage is the virus that infect bacteria.Bacteriophages were discovered by Frederick Twort(1915)and Felix d'Herelle(1917).
0.1 What are viruses?
1. Origin of viruses
1.1 introduction
1.2 Theories
RNA molecules that existed before cells
cell components
micro-organisms.
1.3 Conclusion: How did viruses originate?
Signal transduction in plant defence responsesrkravikirankt
Plant respond to the attack of diseases by triggering various bio-molecules insider their system to combat the infection and establishment of the pathogens. these response operate in specified pathways mediated by many enzymes starting from the infection site to the nucleus which together constitute the signal transduction pathway.
plant pathogen interaction
different types of pathogens
gene for gene hypothesis
direct receptor model
Elicitor receptor model
suppersor repressor model
gaurd hypothesis
Plant - Pathogen Interaction and Disease DevelopmentKK CHANDEL
Plant diseases are the result of infection by any living organisms that adversely affect the growth, development, physiological functioning and productivity of a plant, manifesting outwardly as visible symptoms.
Host pathogen interactions - This presentation is about the Host pathogen interaction played between bacteria virus and the human body and it also explains about the different protein and enzymes secreted by pathogens to cause infection and diseases in human like the release of endotoxin and exotoxin.
A communicable disease is an illness due to a specific infectious (biological)agent or it's toxic products capable of being directly or indirectly transmitted from man to man,from animal to man,from animal to animal,from the environment (through air,water,food etc)to man.
Lec 1. introduction to infectious diseaseAyub Abdi
Introduction to the infectious disease, how they transmitt and the stratigies used for the management of infectious disease because it's more in tropical and subtropicals
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
2. Terms "infection" and "disease" are not
synonymous
Infection results when a pathogen invades and begins
growing within a host.
Disease results when, as a consequence of invasion and
growth of a pathogen, tissue function is impaired.
•Our bodies have defense mechanisms to prevent infection
and, should those mechanisms fail, to prevent disease after
infection occurs.
4. Host Infection and Pathogens
Occurrence and Spread of Infection:
• Infection occurs when micro-organismsm (pathogen) invade sterile
body tissues
• infectious disease occurs when infection is associated with
clinically manifested tissue damage
• Colonization- presence of organisms on a body surface or in a
lumen, but not producing disease
• All persons have bacteria (and some fungi) on skin surfaces or in the
oral cavity
• Invasion of tissues (avoids immune system) organisms have
moved into tissues to cause disease
• Toxin production (endotoxin or exotoxin) toxins can be produced in
body or ingested
5. Host
• A person (or animal) who permits lodgment of an
infectious disease agent under natural conditions.
• Once an agent infects the host, the degree & severity of the
infection will depend on the host’s ability to fight off the infectious
agent.
6. Defense mechanisms present in host:
• Resistance: ability of the host to prevent infection from
occurring & infectious disease from developing
• Resistance is normally aided by:
• Barriers to infection: intact, functional epithelial surfaces
(respiratory tract, gastric acid, antibacterial action of bladder
secretions and saliva of oral cavity)
• Immune system
• Nonspecific
• Examples: skin, mucosal surfaces, tears, saliva, gastric juices, &
the immune system.
• Nonspecific defense mechanisms such as immunity may decrease
as we age.
• Disease-specific
• Immunity (resistance) against a particular agent.
7. 7
Resistance
• Resistance diminished by:
• Debilitation from malnutrition (poor diet, alcoholism)
• Cancer
• Poorly functioning immune system (congenital or acquired)
• Drug therapy – corticosteroids, antibiotics
• Previously damaged or abnormal anatomical structure
Black (2008)
8. Environment: Source &
Reservoir
• Source: immediate site from
which pathogen transferred to
host. Can be human, animal,
inanimate (water, soil, food)
• Reservoir: where infectious
organisms live & multiply;
• humans often reservoir and host.
• Common ones: feces, food,
water
Source and Reservoir: example:
Yellow fever in jungle areas:
• reservoir = monkeys
• source = mosquitoes (vector)
carrying virus from infected
individuals
9. Why do pathogens cause disease and
some don't?
• Virulence! the ability of an organism to cause infectious
disease
• Some infectious agents are easily transmitted (very contagious),
but they are not very likely to cause disease (not very virulent).
• Ex: polio virus : probably infects most people who contact it, but only
about 5 - 10 % of those infected actually develop clinical disease.
• Other infectious agents are very virulent, but not terribly
contagious.
• Ex; Ebola hemorrhagic fever virus virulence very high (50 - 90 % fatality rate
among those infected); however, virus not transmitted easily by casual
contact.
11. The Movement of Pathogens Out of
Hosts: Portals of Exit to Portals of Entry
• Pathogens leave host through portals of exit
• Many portals of exit are the same as portals of entry
• Pathogens often leave hosts in materials the body
secretes or excretes
12. 12
Sites of Entry / Cause / S/S
• Ingestion into gastrointestinal tract;
• microorganisms contaminating food or water
• Salmonella, Vibrio cholera
• S/S abdominal pain, nausea, vomiting, diarrhea
• Inhalation into respiratory tract;
• microorganisms in air
• S/S cough, chest pain, shortness of breath, coughing blood
• Ascension into urinary tract;
• microorganisms that enter bladder through urethra or catheter
• S/S painful urination, blood in urine, pelvic pain, flank pain
• Ascension into biliary tree
Black
• microorganisms entering common bile duct from GI tract (2008)
• S/S abdominal pain, jaundice
13. 13
Sites of Entry / Cause / S/S
• Crossing of mucosal surfaces
• microorganisms that penetrate oral, anal, genital, or conjunctival
linings
• S/S Human papillomavirus, HIV, herpes simplex virus, Neisseria
gonorrhea
• Experience local irritation, ulceration, pain, redness
• Entrance through wound sites
• Direct inoculation of micro-organisms leads to direct spread
Black (2008)
14. Three groups of transmission
• Contact transmission
• Vehicle/ fomite transmission
• Vector transmission
• Biological or mechanical
Fomites: inanimate objects that transmit disease
Vector: insect or small animal carrier of disease
15. Contact transmission
• Direct: (person-to-person): through direct physical contact
(skin-to-skin or body fluids) eg.., STDs, cold sores
• Indirect: pathogens or agents transferred via intermediate
item, organism etc. to susceptible hosts.
16. Vehicle/ fomite transmission
Airborne: pathogen suspended in
droplets or dust; can remain in air for
hours to days
e.g., cold virus travels in droplets
when person sneezes, talks
Vehicle-borne: pathogen transmitted
from source to susceptible individual via
intermediate object (fomite)
e.g., contaminated medical
equipment
17. Vehicle/ fomite transmission
Food or Waterborne: Pathogen transmitted to susceptible
individual via or food water.
• intoxication: Chemical or toxin causes body malfunction.
• e.g., lead, botulism
• infection: Ingestion of pathogenic organism that grows in GI tract.
• e.g., V. cholera transmitted in water sources; E. coli in hamburger
18. Vector borne transmission
Pathogen transmitted to
susceptible individual via
animal or insect.
• mechanical transmission
(external): use a host for transport;
• e.g., fly landing on food at picnic
after it picked up some e.coli
• biologic transmission (internal)
carried inside vector; use vector for
part of life cycle
• e.g. malaria parasite Plasmodium in
blood ingested by Anopheles
mosquito after bite
19. 19
Spread of Infectious Agents In
Body via the bloodstream
• Travel
– Septicemia
• Travel via the lymphatic system
– Enlarged tender lymph nodes suggest possible infection at site
• Travel via the body cavity
– Can spread in cerebrospinal fluid, peritoneal fluid, joint space
• Crossing of the placenta to fetus
– Basis for congenital infection
Black (2008)
20. The Natural Course of Disease
sequence of events in infectious
disease
ncubation
interval
between
exposure &
1st
appearance
of disease
s/s
Prodromal
1st
disease s/s
Fastigium Defervescence Convalescence
disease
at its peak
.
disease s/s
decline
recovery
period
Defection
pathogen
killed off or
brought into
remission
21. Number of microorganisms or
intensity of signs or symptoms
FIGURE 14.10 THE STAGES OF INFECTIOUS DISEASES
Incubation Prodromal
period
period
(no signs or (vague,
symptoms) general
symptoms)
Illness
(most severe signs
and symptoms)
Time
Decline
Convalescence
(declining signs (no signs or
and symptoms) symptoms)
22. Barriers to Decreasing Disease
Transmission
• Increases in host susceptibility due to changes in
•
•
•
•
•
demographics and behavior
Microbial adaptation and change (eg. drug resistance)
Emergence of new diseases
Breakdown of public health measures
International travel and commerce
Changes in the environment, technology, and industry
Cohen, M. L. (2000). Changing patterns of infectious disease. Nature, 406(6797),
762-767. doi:10.1038/35021206)
22
23. Human Microbiome Project
(HMP)
aims to characterize the microbial communities found at
several different sites on the human body, including nasal
passages, oral cavities, skin, gastrointestinal tract, and
urogenital tract, and to analyze the role of these microbes
in human health and disease.
Human Microbiome Project: Analyzing microbes that play a
role in health and disease
http://www.youtube.com/watch?v=axB_8O4WHYg
3 min
Editor's Notes
In order to cause disease, pathogens must be able to enter the host body, adhere to specific host cells, invade and colonize host tissues, and inflict damage on those tissues. Entrance to the host typically occurs through natural orifices such as the mouth, eyes, or genital openings, or through wounds that breach the skin barrier to pathogens. Although some pathogens can grow at the initial entry site, most must invade areas of the body where they are not typically found. They do this by attaching to specific host cells. Some pathogens then multiply between host cells or within body fluids, while others such as viruses and some bacterial species enter the host cells and grow there. Although the growth of pathogens may be enough to cause tissue damage in some cases, damage is usually due to the production of toxins or destructive enzymes by the pathogen. For example, Corynebacterium diphtheriae, the bacteria that causes diphtheria, grows only on nasal and throat surfaces. However, the toxin it produces is distributed to other tissues by the circulatory system, damaging heart, liver, and nerve tissues. Streptococcus pyogenes, the infectious agent associated with several diseases including strepthroat and "flesh-eating disease," produces several enzymes that break down barriers between epithelial cells and remove fibrin clots, helping the bacteria invade tissues.
In order to cause disease, pathogens must be able to enter the host body, adhere to specific host cells, invade and colonize host tissues, and inflict damage on those tissues. Entrance to the host typically occurs through natural orifices such as the mouth, eyes, or genital openings, or through wounds that breach the skin barrier to pathogens. Although some pathogens can grow at the initial entry site, most must invade areas of the body where they are not typically found. They do this by attaching to specific host cells. Some pathogens then multiply between host cells or within body fluids, while others such as viruses and some bacterial species enter the host cells and grow there. Although the growth of pathogens may be enough to cause tissue damage in some cases, damage is usually due to the production of toxins or destructive enzymes by the pathogen. For example, Corynebacterium diphtheriae, the bacteria that causes diphtheria, grows only on nasal and throat surfaces. However, the toxin it produces is distributed to other tissues by the circulatory system, damaging heart, liver, and nerve tissues. Streptococcus pyogenes, the infectious agent associated with several diseases including strepthroat and "flesh-eating disease," produces several enzymes that break down barriers between epithelial cells and remove fibrin clots, helping the bacteria invade tissues.
