A microorganism that does not cause disease, may be part of the normal microbiota
An agent capable of causing disease only when the hosts resistance is impaired (immunocompromised patient)
A microorganism capable of causing disease
Pathogens ability to evade and overwhelm the host defense mechanisms and cause disease
Portal of Entry?
Route by which a pathogenic microorganism infects the host
Protein toxins that activate the immune system by binding to major histocompatibility complex (MHC) molecules and T cells receptors (TCR) Stimulate large numbers of T cells to produce massive quantities of cytokines
The ability of a microorganism to produce a toxin that contributes to the development of disease
Localization of a virus or disease to specific cells or tissues, generally determined by cellular receptors
Concentration of viral particle
Is the degree of pathogenicity of an organism; the quantitative ability of an agent to cause disease. Virulent agents cause disease whrn introduced into the host in small numbers. Virulence involves adherence, persistence, invasion, and toxigenicity
What are the stages of infection?
-Transmission, horizontal, vertical, vector borne or not - Colonization: Adherence and Tropism - Invasion - Multiplication - Spread
What is horizontal, vertical and vector borne transmission?
Horizontal- Get it from someone else Vertical- Transmission from Mom to fetus - Vector borne- Need another animal to deliver the infection (Mosquito)
Transmission can be human to human and there are 4 what are they?
- Respiratory or salivary (flu) - Fecal-oral- (Rotavirus) - Congenital- Mother fetus - Blood or blood products HIV
What is the other type of transmission?
Vector-Vector-vertebrate, insect bites, dengue yellow fever - Vertebrate reservoir- Dog bites, rabbies
The most often portal of entry for infection is?
Mucosal membrane, of respiratory, Gi, and genitourinary tracts
What are the factors that influence the severity of an infection?
- MOA - Infectivity - Pathogenicity - Virulence - Immunogenicity - Toxigenicity - Portal of Entry
Shedding is significant in what disease? And what does it mean exactly
In HIV, When the patient is infected but doesn't show any symptoms to make you think you have it.
What are the four stages of infection and what other stage can happen?
-Incubation - Prodromal Stage - Invasion Period -Symptoms - Convalesence - getting better - Latency and reactivation can occur meaning the disease can come back like chicken pox --> Shingles
What is an acute infection?
Its often a primary infection - Viral replication starts then followed by a strong immune response and decrease in viral titers (concentration)
What is a Latent Infection?
It is not recognized by the immune response by maintaining silent, the genome remains untranscribed Then it reactivates occasionally (HSV)
What is a persistent infection?
Its persists at high titers in the tissue. Associated with immune tolerance due to deletion and exhaustion of antigen specific T Lymphocytes (HBV)
What are the two types of Viral Spreading?
- Pathogen confined to site of entry - Pathogen causing generalized infection by spreading through
Pathogen causing generalization by spreading through what? Systemic spreading
Septicemia- (Bateria from one infection spreading to blood) Sepsis- When the body responds to an infection and starts to injure its own tissues?
What are the pathogen defense mechanisms?
- Has a surface coat that can inhibit phagocytosis, surface receptors to bind host cells and toxins - Antigenic Variation + Mutation, Antigenic Drift - Recombination Antigenic shift - Gene Switching - Bacterial communication
Pathogenic Adaptations Include?
- Suppression of immune response - Antigenic Changes - Development of resistance
Acute primary infection for AIDS occurs whem?
Within weeks of infection , virus infects mucosal T vell, High levels of Viremia (Spread through blood) Spread to lymphoid organs 3-6 weeks without immune response
During Latency of AIDs what happens?
The initial immune response occurs. Staying silent
AIDs occurs when? CD4 levels
Number of CD4+ fall below 200 cells/microliter
Primary infection is diagnosed by?
HIV-RNA, HIV-1 by ELISA
HIV most importantly causes?
Opportunistic pathogens and Cancers
M-tropism attacking macrophages ---->
T-tropism which attack CD4+ T cells especially ones that are anti HIV specific.
Explain the precess of HIV infections and when its most apparent that it is HIV
TB occurs with what very often?
Microbacterium Avium is a ____ infection
Protozoal oppotunistic infection
Cryptosporidiosis, GI Toxoplamosis of brain
Viral infections like _____ are oportunistic viral infections that cause disease and are originally in out bodies when infected by AIDs
CMV- specific for HIV EBV- oral hairy leukoplakia KSV, Sarcoma- most common AIDs related malignancy
Hep B and __ are ____ infections when diagnosing aids
and C are coinfections
AIDs defining list?
1) Viral- Kaposi sarcoma caused by Herpesvirus type 8 (HHV-8) - Oral hairy Leukiplakia by EBV - CMV infections (other than liver, spleen or nodes) 2) Bacterial- Mycobactrium avium complex (MAC) Disseminated 3) Fungal - Pneumocyctis pneumonia - Cryprococcal infections in CNS - Candidiasis in esophagus Protozoan: Toxoplasmosis
Advanced stage of AIDs - Poor absoprtion of nutrients - Chronic weakness makes the body more susceptible - Diarrhea - Cytokine production
CNS symptoms in HIV?
-Neuropathy -Myopathy - CNS neoplams opportunistic infections
Stages of AIDs
-Appearance of infections that are otherwise easy to treat - Cannot recover - Progressive worsening of opportunistic infections -Weakness, neuropathy, pain, Cognitive impairment - Death
Cell number and AIDs defining illnesses
Cancers in HIV
Almost always infectious related cancers
RNA virus that replicates itself through DNA intermediate
cp120 and cp41
bind to CD4-
HIV virus has to___ What are these called and do all use both?
Through itself via Chemokine receptors CXCR4 (X4) and CCR5 (R5) Some only use CCR5 and some only CXCR4 Yes they can use both
Once HIV bind to CD4 receptor and CXCR4 or CCR5 receptor what happens?
Begins to fuse and RNA begins to float inside cell - Reverse transcriptase polymerase form RNA on virus- Goes RNA-->DNA copy - DNA copy then improrted into the nucleus and goes into the genome (random spot) - Once inside genome there is now a DNA copy of the virus - Then positive strand RNA is formed to make more virus and also transcribe proteins --->translated These are targets for drugs
In order to effectively block HIV you need to do what? Pertaining to drugs
You need to use more than one drug because these viruses make so many errors you have to have multiple classes
High mutation rate from HIV does what?
The immune system will not recognize the changing proteins
Slow replications from HIV? The biggest thing that HIv does is what?
The immunes system recognition. HIV gets into immunepriviledged sites which make it hard for the immune system to get into certain areas that HIV is present in.
Highly active antiretroviral therapy - Combination therapy - Biggest thing clinical trial done 3 years ago, antiretroviral therapy is not jsut for active disease- it can be used profilactically treating a person that is a HIV negative. this decrease transmission like crazy. Its can help prevention of transmission adn start to isolate very similar to what happens with vaccine
HIV entry inhibitor that stops binding with CCR5 receptor - Can interfere with immune response, not effective at all with CXCR4 because CCR5 isnt used
gp120 binds to CD4 and allows for fusion and Gp41 folds the envelope what stops this?
Enfuvirtide T-20 Blocking the virus from getting into the cell fusion inhibitor
Raltegravir, prevent virus DNA from integrating into host genome