Infectious disease and infection control Flashcards
What is an infection?
Infection is a process of tissue invasion by microorganisms, characterized by multiplication of these microorganisms in the body of the host to produce disease.
What is cross-infection?
Cross infection implies transmission of infection between patients as well as patients and health care professionals.
what is community acquired infections?
That may be present at the time of admission or a visit to a hospital or incubating at that time.
what is a Health-Care-Associated Infections?
That could be induced from a source outside the patient’s body (exogenous) or from within the patient’s own body (autogenous) after a visit or admission to a hospital or health care centre.
how is Herpes simplex type 1 contracted?
Herpes simplex type 1 spread by infected saliva
what is the incubation period for Herpes simplex type 1?
2-12 days
what is the clinical features of herpes simplex type 1?
- Orolabialis infection
- sore throat
- fever
- vesicles on pharynx
- buccal mucosa, gingiva & tongue which spreads to lips and face
- lymphadenopathy
- recurrence
how is herpes simplex types 2?
Herpes simplex type 2 spread by sexual contact.
how does herpes simplex affect the skin?
- hsv-1 or hsv-2
- herpetic whitlow
- primary infections
how does herpes simplex affect the eye?
- usually hsv-1
- corneal involvement is serious since it may cause blindness
what is complications of herpes simplex?
- encephalitis - affects temporal lobes
- neonatal - serious since mortality is 60 % due to transfer of HSV-2 during parturition
- indication for a caesarian section
- erythema multiforme
- eczema herpeticum
what is the treatment for herpes simplex?
Acyclovir, Valacylcovir
what is the clinical features of varicella zoster virus?
- preceded by radicular pain and hyperaesthesia of overlying skin
- rash - unilateral, dermatomal
- intense erythema which rapidly become vesicles whichcrust
- oral, palatal or pharyngeal involvement if Trigeminal nerve affected
- ocular involvement causes keratitis or uveitis which may result in blindness
- Ramsay-Hunt Syndrome – reactivation of VZV in the geniculate ganglion of the VII cranial nerve
what is the complication of herpes zoster?
- post-herpetic neuralgia
- neurological e.g. Meningitis
what is the treatment for herpes zoster?
Acyclovir - reduces pain / accelerates healing (no effect on post-herpetic neuralgia)
what is the incubation period Epstein-Barr virus?
4-14 days
what is clinical features of Epstein-Barr virus?
- anorexia, malaise, fever
- sore throat
- cervical lymphadenopathy
- macular rash n.b. Ampicillin
- tonsillitis with white exudate
- palatal petechiae
- palpable spleen
- jaundice (10%)
- Infectious mononucleosis
what is the complication of Epstein-Barr virus?
- hepatitis
- respiratory obstruction
- ruptured spleen (rare - told to avoid contact sports)
what is the diagnosis for Epstein-Barr virus?
Monospot test
what is the incubation period of Varicella zoster virus?
14-16 days
what are the clinical features of Varicella zoster virus?
- rash - appears in crops and progresses from macule to papule to vesicle
- starts on trunk or scalp
- spreads to limbs and face
- vesicles dry and crust
- pruritis
- shallow ulcers on mm’s
what are the complications Varicella zoster virus?
- cellulitis or impetigo
- pneumonia
- neurological e.g. Acute cerebellar ataxia, Reye’s syndrome
- congenital abnormalities
what are the treatments for varicella zoster virus?
- Antihistamines
- Acyclovir (severe cases/complications)
What is the incubation period for mumps?
16-21 day
how is mumps spreaded?
Spread by droplets from saliva and nasopharyngeal secretions
what is the clinical features of mumps?
- asymptomatic in 40%
- fever, malaise, “angle pain”
- enlargement of one or both parotids
- earache and displacement of earlobe
- parotid papillae inflamed
- difficulty in swallowing
- submandibular glands may be affected
what are the complications of mumps?
- neurological - aseptic meningitis, encephalitis
- orchitis - 20-25% in post pubertal
- non-parotid mumps - ovaries, thyroid, pancreas, breasts
what are the treatment for mumps?
- good oral hygiene
- scrotal support
- bed rest in meningitis
what is the incubation period for measles?
10 days
what is the clinical features of measles?
- conjunctivitis (res eyes),
- lymphadenopathy
- Koplik’s spots on buccal mucosa
- florid maculopapular rash which begins behind the ears and spreads to the face and trunk – brownish discolouration remains after
what is the complications of measles?
gingivostomatitis
what is the treatment of measles?
Treatment is supportive while any complications are treated as appropriate
what is the incubation period for rubella?
14-21 days
what is the clinical features of rubella?
- fever, malaise, catarrhal
- lymphadenopathy
- rash - starts face → trunk/limbs
- pink maculopapular, non-confluent
- Conjunctivitis
what is the diagnosis for rubella?
essential in pregnant women
what is the complications of rubella?
congeniatial rubella
what is four catergories of transmission of Corona virus disease (covid-19)?
- symptomatic transmission (direct transmission from a COVID-19 patient)
- presymptomatic transmission (direct transmission from a SARS-CoV-2 positive person without symptoms yet)
- Asymptomatic transmission (direct transmission from a SARS-CoV-2 positive person who never developed symptoms)
- environmental transmission (indirect transmission which is not traceable to an index patient)
how did dentist treatment during covid 19?
Aerosols generated during dental health care treatment in these individuals can also contain SARS-CoV-2.
Aerosol dispersion should be minimised by adjusting dental treatment procedures, for example by using hand instruments instead of water cooled instruments or ultrasonic cleaning devices.
what are 4 types of active immunity?
Live attenuated vaccines
Inactivated organisms
Immunising components of organism
Toxoid
what are 2 types of passive immunity?
Natural transmission from mother to foetus
Artificial
what is the incubation period for Hepatitis B?
45 to 180 days.
what is the mode of transmission for Hepatitis B?
Direct contact with infected blood.
what is the prevention for Hepatitis B?
all members of dental team should be vaccinated against hepatitis B.
what kind virus is Hepatitis B?
- DNA virus.
what kind of virus is hepatitis C?
- It is a RNA virus.
what are the dental clinical features of hepatitis C?
Lichenoid reaction; Xerostomia
what are the dental clinical features of HIV?
- HIV seropositive periodontal conditions, candidiasis
- Clinical signs of viral infections as early indicators of conversion to AIDS
- Increased frequency of minor oral infections.
what Diseases strongly associated with HIV infection
Candidiasis
Hairy Leukoplakia
Kaposi’s Sarcoma
Non-Hodgkin’sLymphoma
what virus causes Erythema infectiosum?
Parvovirus B19
what are the clinical features of erythema infectiosum?
- constitutional symptoms uncommon
- rash - livid erythema of cheeks (slapped cheeks)
- then maculo-papular on extremities and trunk
- as second fades it assumes a lacy reticular appearance
Is there treatment for erythema infectiosum?
Diagnosis is made clinically and there is no specific treatment
what is scarlet fever caused by?
Group a beta-haemolytic streptococci which produces erythrogenic toxin.
what are the clinical features of scarlet fever?
- follows a pharyngeal infection
- rash - diffuse erythema which blanches on pressure
- skin folds are dark
- circumoral pallor
- strawberry tongue
how to treat scarlet fever?
Treatment is penicillin
what causes whooping cough?
Bordetella pertussis (gram negative bacillus)
what is the incubation period of the whopping cough?
Incubation period is 7 days and is followed by the “catarrhal” phase which lasts 1-2 weeks
Spasmodic phase occupies next 4-6 weeks & consists of :
* severe paroxysmal cough with an inspiratory “whoop“
* vomiting
* cyanosis or apnea
what are the complications of whooping cough.
- bronchopneumonia - secondary to inhalation of secretions during whoops
- convulsions
- pressure effects - subconjunctival haemorrhage
- facial petechiae during spasm
- cerebral haemorrhage
- prolapse of hernias
- laceration of lingual fraenum against the lower incisors
how is whooping cough investigated?
paranasal swabs and culture on bordet-gengou medium immunofluorescent antibody test.
is there treatment for a whopping cough?
Treatment is symptomatic.
What is tuberculosis caused by ?
Mycobacterium tuberculosis
How is tuberculosis prevented?
Immunization with BCG vaccine.
Gloves and mask should be worn.
Give an example of a fungal infection?
Oral candidiasis. Common opportunistic infection from yeast-like organism Candida albicans.
where are fungal infections typically seen in?
- elderly patients
- Infants
- Medically compromised individuals
what are the signs of fungal infections?
- Pseudomembranous
- Erythematous
- Hyperplastic
- Angular cheilitis
- Median rhomboid glossitis
what are the two types of parasitic infectious agents?
- Local infections
- Systemic infections with indirect effects
give an example of a Systemic parasitic infection.
Protozoan flagellate Leishmania can affect the oral cavity.
Disfigurations/mucocutaneous form of the infection, resulting in granulomatous growth involving the mouth and the nose.
Give an example of Local parasitic infections.
The two protozoa commonly in the oral cavity: T.tenax and E.gingivalis
Associated with poor oral hygiene.
What is the diagnosis of local parasitic infections?
needle aspiration; biopsy
What is the treatment of local parasitic infections?
Treatment:
* Metronidazole
* Leishmaniasis treatment complex: Antimonial, pentamidine and amphotericine B
