Infectious Diseases

Sexually Transmitted Infections 

Why has there been an increase in the number of reported STI’s in recent years? 

Increasing: antibiotic resistance, new pathogens, change in sexual mores/attitudes 

   Gonorrhea 

Which pathogen causes it? Neisseria gonorrhoeae, gram-negative diplococcus 

There’s often a co-infection with what pathogen? Which causes which disease? Chlamydia trachomatyis 

What are the symptoms in men? 

symptoms; painful urination, discharge 

What are the complications in women? 

can lead to systemic infections 

What is opthalmia neonatorum? 

Severe eye infection in newborns caused by exposure 

Why did the incidence increase in the 60s/70s? Sexual revolution, chanign norms/less protection 

Why did the incidence decrease in the 80s? Public health campaigns and increase protection due to AIDS 

Chlamydia 

What does polymicrobic mean? Refers to infections involving multiple microoganisms 

Which pathogen causes it? Chlamydia trachomatyis 

What makes this pathogen virulent? Ability to invade host cell 

What is an obligate intracellular parasite? Pathogen that can only replicate and survive in host cell depends on it 

What it trachoma? Is it an STI? Eye infection, NOT STI, contaminated objects 

Syphilis 

Which pathogen causes it? Treponema pallidum- spiral shaped 

What are the sign/symptoms at each stage: primary, secondary, latent, tertiary 

Primary- chancre at site of infection, Secondary-skin and mucosal rashes, Latent- none, Tertiary stage- Gummas on organs 

What is a chancre? What is a gumma? Chancre= ulcer at infection site at prim stage and usually heals Gumma- soft growth caused by inflammation (tumor like lesions) 

What are the effects of congenital syphillis? 

Passed from mother to fetus during pregnancy, stillbirth, abnormalities, blindness, deafness, and systemic infections. 

What are the leading 3 infectious disease causes of death globally? 

TB, HIV/AIDS, Malaria 

HIV/AIDS 

What animal was the original host for the virus? Chimpanzees 

What are the steps in HIV replication? ATTACHMENT- HIV binds to CD4 receptors, ENTRY-virus fuses with cell membrane release RNA, REVERSE  Transcription – reverse transcriptase converts viral RNA to DNA, INTERGRATION- Integrase incorporates DNA into host, REPLICATION- produces viral proteins, ASSEMBLY- viral proteins and RNA assemble into new virus, BUDDING- new leave, maturing with protease 

Which cells are the target? (which receptors does HIV attach to)? CD4+ T cells 

What do reverse transcriptase, integrase, and protease do? Reverse Transcriptase- converts viral RNA to DNA, Integrase- incorporates viral DNA into host genome, Protease- processes viral proteins for assembly of new viruses 

What happens to CD4 levels, antibody levels, and viral levels as the disease progresses? CD4 levels decrease, antibody levels rise but becomes ineffective, viral levels spike early then stabilize and rise again when CD4 cells are depleted. 

What conditions have to be met for an AIDS diagnosis? CD4 count less than 200 cells or presence of AIDS illness 

What bodily fluids can transmit HIV? Which one can’t? Blood, Semen, Vaginal fluids, rectal fluids, breast milk can, saliva, sweat, tears, urine cannot 

What is meant by Universal Precautions? 

Handwashing, PrEp- medicine that people at risk take 

Malaria 

What mosquito species carries malaria? Anopheles mosquitoes (females) 

How is malaria prevented? Insect repellents, antimalarial drugs (doxycycline), Environmental control, Vaccines RTS 

Where in the US has malaria been a problem?  

Usually Southeastern US 

Tuberculosis 

What percentage of the world’s population is infected with Mycobacterium tuberculosis? 33%  

What is the origin of the name “tuberculosis”?  tuberculum Latin word meaning small swelling 

Rabies 

Which pathogen causes it? Caused by rabies virus (Lyssavirus genus) 

What is furious rabies? Paralytic rabies? Furious Rabies: restless then highly excitable. Paralytic Rabies -seem unaware of surroundings 

What is the pathology of rabies? (which cells/systems are affected and in which order) 

Virus enters tissue from saliva of biting animal; Virus replicates in muscle near bite; Virus moves up peripheral nervous system to CNS; Virus ascends spinal cord; Virus reaches brain and causes fatal encephalitis; Virus enters salivary gland and other organs of victim. 

What is hydrophobia? Fear of water due to painful throat spasms by swallowing common in furious rabies 

What is the most common rabies reservoir in this part of the US? Wildlife- bats, foxes, skunks, cattle 

In the US you are most likely to be bitten by a what type of rabid animal? Raccoons 

What is the treatment for someone who has been bitten by a rabid animal? Vaccine plus rabies immune globulin (RIG) 

What is the mortality rate of rabies? All death without treatment 

In the US, how is most of the population protected from rabies? Active domestic animal vaccination (HDCV)