(50) HIV and STIs Flashcards
(180 cards)
1
Q
What is an STI?
A
Infections which are transmitted person-person by sexual contact - may be asymptomatic (men and women)
2
Q
What is an STD?
A
STI but with evidence of disease (signs and symptoms)
3
Q
Are gentile infectious diseases always sexually transmitted?
A
No, not all are acquired by sexual transmission (act may precipitate)
- normal vaginal commensal flora
- gasto-intestinal flora
4
Q
What are the common bacteria causing STIs in the UK?
A
- N. gonorrhoea
- C. trachomatis
- ureaplasma
- mycoplasma
- (G. vaginalis)
- (anaerobes)
() = not STIs per se
5
Q
What are the uncommon bacteria causing STIs in the UK?
A
- T. pallidum
- H. ducreyi
- K. granulomatis
- C. trachomatic (LGV)
6
Q
What are the common viruses causing STIs in the UK?
A
- herpes simplex virus (HSV)
- human papilloma virus (HPV)
- pox virus (molluscum)
7
Q
What are the uncommon viruses causing STIs in the UK?
A
- HIV
- Hepatitis B
8
Q
Name a protozoa causing STIs in the UK?
A
- trichomonas vaginalis
9
Q
Name a fungus causing STIs in UK?
A
(-candida albicans)
10
Q
Name an ectoparasite causing STIs in UK?
A
- phthirus pubis (crabs)
- sarcoptes scabiei
11
Q
Name 5 common STIs diagnosed at GUM clinics in England and Wales?
A
- chlamydia (44%)
- warts (35%)
- gonorrhoea (11%)
- herpes (9%)
- syphilis (1%)
12
Q
Who are most at risk of being diagnosed with an STI?
A
Age group 16-24
13
Q
How are STIs transmitted?
A
Mucous membrane contact/exchange of bodily fluids
14
Q
STI organisms are often fastidious. What does this mean?
A
A fastidious organism is any organism that has a complex nutritional requirement - in this cases, don’t survive well out in the environment
15
Q
In which infections are the sites of infection/disease predominantly local?
A
- T. vaginalis
- Chlamydia trachomatis
- HSV
- HPV
- Neisseria Gonorrhoea
16
Q
In which infections are the sites of infection/disease mixed?
A
- syphilis (treponema pallidum)
17
Q
In which infections are the sites of infection/disease not local?
A
- HIV
- HBV
18
Q
Give the 2 way which STIs can spread
A
- sexual contact
- vertical transmission = mother to baby
19
Q
How can STIs spread through sexual contact?
A
- male-female genitalia
- oro-genital
- male-male
- female-female
20
Q
How can STIs spread vertically from mother to baby?
A
- in utero = transplacental
- peri-natal = passage through infected birth canal
- eye mucous membrane - conjunctivitis/keratitis
- present in breast milk
21
Q
Give through common concepts concerning STIs/STDS
A
- risk of transmission/acquisition related to number of sexual partners (increased risk with use of non-barrier or no contraception)
- patients with one STD likely to have other STIs/STDs
- contract tracing very important (may be asymptomatic)
22
Q
What is the cause of gonorrhoea (the clap)?
A
Neisseria gonorrhoeae
23
Q
Why type of organism is neisseria gonorrhoeae?
A
Gram negative coccus - diploccocus - in pairs (resemble coffee beans)
24
Q
What are the other Neisseria species?
A
- N. meningitidis
- non-pathogenic neisseria species (normal commensal flora in throat and genital tract)
25
Neisseria gonorrhoea have pili on cell surface. Why?
Piliated cells more virulent
- increased ability to attach to mucosal epithelial cells
- primarily infect junction between columnar and cuboidal epithelium
(intracellular, phagocytosis, intracellular-multiplication)
26
Describe the structure of the neisseria gonorrhoea cell envelope
Has 3 layers like all gram negative bacteria
- inner cytoplasmic membrane
- thin peptidoglycan wall
- outer cytoplasmic membrane (lipo-oligosaccharides)
27
Where do gonorrhoea affect?
- GU tract
- rectum
- oropharynx
28
What is the incubation period of gonorrhoea?
2-5 days (short)
29
How often is gonorrhoea asymptomatic?
60% of women asymptomatic
30
What is a symptom of gonorrhoea?
- urethral discharge
| - dysuria (stinging on passing urine)
31
What are the local complications of gonorrhoea?
- epididymitis
- prostatitis
- barthonilitis
- salpingitis
- PID
- peritonitis
- Fitz-Hugh-Curtis syndrome (perihepatitis)
32
If a gonorrhoea patients has perihepatitis, they are usually co-infected with what?
C. trachomatis
33
What is barthonilitis?
Inflammation of one or both of the two Bartholin's glands, which are located one on either side of the opening of the vagina
34
What is salpingitis?
Inflammation of the fallopian tubes
35
What is DGI?
Disseminated gonococcal infection - more widespread metastatic disease caused by gonorrhoea
36
How often does DGI occur?
0.5-3% of untreated cases - increased with certain strains
Up to 13% of DGI is due to complement deficiency
37
What are the complications of disseminated gonococcal infection?
- bacteraemia
- arthritis
- dermatitis
- (meningitis)
38
What can gonorrhoea in pregnancy cause?
- spontaneous abortion
| - premature labour
39
What can gonorrhoea cause in the neonate?
- ophthalmia neonatorum
- acute purulent conjunctivitis less than 5 days post-delivery
- can cause blindness if not treated appropriately
40
Name 3 methods of gonorrhoea diagnosis
- microscopy
- culture
- nucleic acid amplification test (NAAT) eg. PCR
41
How is gonorrhoea diagnosed by microscopy?
- urethral swab (male)
- GNID = gram-negative intracellular diplococci
- high sensitivity/specificity
42
How is gonorrhoea diagnosed by culture?
- selective plates (because fastidious) for 48 hours
- endocervical (columnar epithelial cells) (not high vaginal) - sens = 80-90%
- OR urethral swab, sens over 95% in men
- high specificity (confirm no n. meningitidis/other spp)
- antibiotic sensitivity testing (typing)
43
How is NAAT e.g. PCR used in gonorrhoea diagnosing?
- multiplexed with C. trachomatis
- urine/vaginal swab
- specificity over 99%
- positive predictive value over 95% if prevalence 0.5%
44
What is multiplex PCR?
A modification of polymerase chain reaction in order to rapidly detect deletions or duplications in a large gene. This process amplifies genomic DNA samples using multiple primers and a temperature-mediated DNA polymerase in a thermal cycler
45
Give 3 antibiotic types used in the treatment of gonorrhoea
- B-lactams
- cephalosporins
- fluoroquinolones
46
Give examples of B-lactams used in the treatment of gonorrhoea
- benzylpenicillin
| - amoxicillin
47
How did gonorrhoea develop resistance to B-lactams in the 1970s?
- B-lactamase
| - PBP change (penicillin-binding proteins)
48
Name 2 cephalosporins used in the treatment of gonorrhoea
- cefixime (oral)
| - ceftriaxone (IV or IM route)
49
Name a fluoroquinolone used in the treatment of gonorrhoea
- ciprofloxacin (but increased resistance)
50
Name 3 other antibiotics used in the treatment of gonorrhoea (other than B-lactams, cephalosporins, fluoroquinolones)
- spectinomycin
- azithromycin
- tetracycline (but widespread resistance)
51
Name 2 antibiotics used in the treatment of gonorrhoea, that as of 2007 had 0% total resistance
- ceftriaxone
| - spectinomycin
52
What is the recommend treatment of gonorrhoea according to BASHH 2011?
- Std: ceftriaxone 0.5mg IM
- and azithromycin 1g PO
- and all cases "test of cure"
53
What is a problem with cefixime/ceftriaxone?
Decreased susceptibility. High level of resistant strains in some areas recently, eg. Japan, France 2011
54
What is NGU?
Non-gonococcal urethritis
55
What organisms can cause non-gonococcal urethritis?
- mostly chlamydia trachomatis types D-K
- ureaplasma urealyticum (mycoplasma genitalium)
- trichomonas vaginalis
etc.
56
What is the incubation period in NGU?
1-2 weeks
57
How is NGU diagnosed?
- currently NAAT for chlamydia
| formerly enzyme immunoassay:EIA/ELISA
58
How is NGU treated?
- doxycycline
| - macrolides eg. erythromycin, azithromycin
59
Describe the chlamydia trachomatis bacteria
- obligate intracellular pathogen
- gram-negative
- ovoid in shape and non-motile
60
Chlamydia trachomatis has a unique lifestyle that includes which 2 stages?
- extracellular infectious form = elementary body
| - intracellular replicative form = reticulate body
61
What are the target cells for chlamydia trachomatis?
- squamo-columnar epithelial cells of endocervix/upper genital tract in females
- conjunctiva, urethra and rectum in males and females
- also respiratory tract cells in infants
62
Which age groups have highest rates of chlamydia?
- women = 16-19
| - men = 20-24
63
What is the prevalence of chlamydia in the UK?
- 16-44yr olds: 1.5% of sexually experiences females, 1.1% males
- 16-24yr olds: 3.1% of females, 2.3% males
64
Who is screened (ie. asymptomatic) for chlamydia in the National Chlamydia Screening Programme?
All sexually active under 25 year olds, annually, or on change of partner
65
What happens if somebody tests positive for chlamydia?
They are treated and then re-tested 3 months post-treatment (10-15% will be positive due to new/re-acquisition or very rarely, treatment failure)
66
What else is important in positive chlamydia tests?
Partner notification
67
What are the symptoms of chlamydia?
- often asymptomatic (female more than male)
- urethritis (but less purulent discharge than gonococcal)
- cervicitis (mucopurulent)
- dysuria/frequency (a cause of "acute urethral syndrome" - sterile pyuria on standard urinalysis)
68
What do you see at the cervix in chlamydia cervicitis?
- cervical friability (easily irritated and inflamed and can bleed)
- oedema
- ectopy
69
What are the complications associated with chlamydial infection?
- pelvic inflammatory disease (PID)
- epididymitis (2%)
- complications in neonate/infant
- conjunctivitis
- Reiter's syndrome
70
How often does PID occur in chlamydia?
Over 9.5% within one year, without treatment
71
When PID occurs in chlamydia, what other complications can it be related to?
- perihepatitis (spread of infection from PID)
- tubal infertility (10.6% of PID)
- ectopic pregnancy
- chronic pain
72
What problems in the neonate/infant can chlamydia cause?
- conjunctivitis (later onset than with N. gonorrhoeae - 5-12 days)
- infant pneumonia (usually present at 4-11 weeks)
73
Chlamydia can cause Reiter's syndrome. What is this characterised by?
- arthritis
- conjunctivitis
- urethritis
- skin lesions
74
How is chlamydia diagnosed?
- histology: inclusion bodes (elementary bodies)
- cell culture
- NAAT (superseded EIA)
- serology (limited value in most oculogenital infections)
75
What is the sensitivity and specificity in NAAT for chlamydia?
Sensitivity: - cervix = 81-100%
- urine female = 80-96%
- urine male = 90-96%
Specificity = 99.7%
76
How is chlamydia usually treated?
- azithromycin 1g PO single dose
OR
- doxycycline 100mg BD for 7 days
77
How is paediatric chlamydia treated?
Conjunctivitis/pneumonia: erythromycin for 14 days
Treat parents as well
78
What is pelvic inflammatory disease (PID)?
An infection of the female upper genital tract, including the uterus, fallopian tubes and ovaries
79
How does PID affect fertility?
1st, 2nd and 3rd episodes associated with 10%, 30% and 50% risk of infertility
80
What is used in PID diagnosis?
- diagnostic difficulties
| - laparascopy
81
Name 2 most common infective agents causing pelvic inflammatory disease
- N. gonorrhoeae (30% of patients also have chlamydia)
| - C. trachomatis
82
There are over 100 HPV types. How many 'high-risk' types are there?
Around 12
83
The 12 high-risk HPV types are causally associated with what?
Cervical cancer - causing 1000 death in UK each year
84
What are the low-risk HPV types associated with?
Not associated with cancer but cause warts (genital and other)
85
Name 2 low-risk HPV types and what they cause
HPV 6, HPV 11 - 90% genital warts
86
Name 2 high-risk HPV types and what they cause
HPV 16, HPV 18 - 70% cervical carcinomas (also some oesophageal cancers)
87
What does cervarix (GSK) vaccinate against?
Bivalent vaccine (HPV 16 and 18)
88
What does gardasil (MSD) vaccinate against?
Quadrivalent vaccine (HPV 6, 11, 16, 18)
89
What is condylomata accuminata?
An epidermal manifestation attributed to HPV eg. warts
90
How are genital warts treated?
- burning, freezing or cutting
- imiquimod cream
- podophyllin
- salicylic acid
- trichloracetic acid
- liquid nitrogen
91
What causes genital herpes?
Herpes simplex types 2 and 1
- double-stranded DNA viruses
- HSV-2 more common in women than men
92
What are the symptoms of genital herpes?
- pain
- itching
- dysuria
- vaginal/urethral discharge
- bilateral vesicles/ulcers - viral shedding
- accompanied by constitutional symptoms
93
What can cause reactivation of latent HSV infection?
- local trauma
- menstruation
- stress
94
How is genital herpes diagnosed?
- clinical
- PCR (HSV 1 or 2)
- histology
95
How is genital herpes treated?
- acyclovir
| - consider suppression if frequent recurrence
96
What are the complications associated with genital herpes?
- dissemination
- meningitis
- encephalitis
- sacral nerve parasthesiae
- urinary retention
97
Where does HSV reside when latent?
- sensory neurone cells - sacral nerve ganglia
98
Which organism causes syphilis?
Treponema pallidum (a spirochaete - helically coiled, thin)
99
Describe treponema pallidum (cause of syphilis)
Slender, helical, tightly coiled cells
- too thin for light microscopy
- cannot be readily culture in vivo
100
How does treponema palladium penetrate?
Through intact mucous membranes of via abraded skin
101
How does treponema palladium disseminate?
Disseminated within days via lymphatics/bloodstream - causing subsequent clinical symptoms and signs
102
What is the characteristic sign of syphilis on histology?
Obliterative endarteritis - severe proliferating inflammation of intima causing occlusion of lumen
- concentric endothelial/fibroblastic proliferation
- microscopic vascular compromise
103
What is obliterative endarteritis caused be?
Radiation poisoning, TB meningitis or a syphilis infection
104
What is the incubation period for syphilis?
Median 21 days
105
What is usually the first sign/symptom of syphilis?
A chancre - a painless indurated lesion that occurs at the site of inoculation - heals spontaneously within 3-6 weeks
106
What is the secondary phase of syphilis?
Most florid phase - 2-8 weeks post onset of chancre
107
What are the skin symptoms in syphilis?
- rash
- condylomata lata
- mucous patches
108
Describe the rash in syphilis
- macular/maculopapular
| - on the trunk, limbs - palms and soles
109
Describe condylomata lata in syphilis
Wart-like lesions - tend to occur in warm body areas
- erythematous plaques
- highly infectious
110
What are "mucous patches" that occur in the secondary phase of syphilis?
Silvery-grey erosions on mucous membranes
111
What are the constitutional symptoms that occur in syphilis?
- fever
- malaise
- weight loss
112
Other than skin manifestations and constitutional symptoms, what are the other symptoms of the secondary phase of syphilis?
- generalised lymphadenopathy (may include epitrochlear)
| - CNS involvement (40%) - headache and meningismus
113
What is meningism?
Triad of:
- nuchal rigidity
- photophobia
- headache
114
What happens after the secondary phase of syphilis?
- spontaneous resolution after 3-12 weeks
- latent = no clinical manifestation but positive serology
- without treatment, 30% will develop tertiary syphilis (late syphilis)
115
Tertiary (late) syphilis may present as neurosyphilis which includes what symptoms?
- meningovascular (hemiplegia, seizures)
| - parenchymatous: general paresis (cortex) and tabes dorsalis (spinal cord)
116
What does general paresis in tertiary syphilis cause?
- personality changes
| - Argyll Robertson pupils: accomodate to near vision by reducing in size, but don't react to light (don't constrict)
117
What is tabes dorsalis? (happens in tertiary/late syphilis)
Demyelinsation of the posterior column, dorsal roots, dorsal root ganglia. Therefore loss of sense in proprioception, vibration and discriminative touch
- ataxic wide-based gait
- lightening pains in legs
118
What are the cardiovascular manifestations of tertiary/late syphilis?
- aortitis
- aortic regurgitation
- saccular aneurysm
119
What is a gumma?
Soft, non-cancerous growth resulting from the tertiary stage of syphilis. It is a form of granuloma (late benign syphilis)
- non-specific granulomatous reaction
120
Where do gummas affect?
Any organ eg. liver. Most commonly bone/skin/soft tissue
121
What is congenital syphilis caused by?
In-utero transmission
122
What is the greatest risk congenital of syphilis?
Spirochaetaemia of early syphilis
123
What are the early signs of congenital syphilis?
- snuffles
- rash
- hepatosplenomegaly
124
What are the late signs of congenital syphilis?
- frontal bosses
- saddle nose
- sabre shins
- Hutchinson's incisors
125
How is syphilis diagnosed?
Direct detection:
- dark field microscopy
- PCR (more sensitive than microscopy)
Indirect tests: serology
126
What is dark field microscopy? (used in the diagnosis of syphilis)
Excludes the unscattered beam from the image. As a result, the field around the specimen (i.e., where there is no specimen to scatter the beam) is generally dark
127
What are the 2 groups of serology tests used in syphilis diagnosis?
- specific
| - non-specific
128
Describe the specific serology test for syphilis
- anti-treponemal antibodies (EIA, TPHA, FTA)
- sensitive and specific
- but won't zero-convert post treatment
129
Describe the non-specific serology test for syphilis
- reaginic antibodies versus lipoidal antigens
- VDRL, RPR (rapid plasma reagin) tests
- false positives, but usually sero-convert post successful treatment - can monitor with titres
130
How is syphilis treated?
Penicillin-based antibiotics
| - length and route (IM/IV) depends on stage and site
131
What is the Jarish-Herxheimer reaction? (classical in penicillin treatment of syphilis)
A reaction to endotoxin-like products released by the death of harmful microorganisms within the body during antibiotic treatment - commonest in secondary stage syphilis
- release of heat-stable protein
132
What are the symptoms of the Jarish-Herxheimer reaction?
- fever
- chills
- myalgia
Usually self-limiting
133
What are the alternative antibiotics that can be used in syphilis treatment?
- amoxicillin
- ceftriaxone
- doxycycline
134
What is trichomoniasis caused by?
Trichomonas vaginalis
135
What type of organism is trichomonas vaginalis?
Anaerobic, flagellated protozoan parasite
| - lacks mitochondria (has hydrogenosome)
136
How is trichomonas vaginalis transmitted?
Trophozoite transmitted, no known cyst
Humans are the only natural host
137
What are the symptoms of trichomoniasis?
Profuse greenish frothy vaginal discharge and mucosal inflammation
138
How is trichomoniasis diagnosed?
Microscopy/culture (high vaginal swab)
139
What is used to treat trichomoniasis?
Metronidazole
140
Can males get trichomoniasis?
Yes but usually asymptomatic, but may have urethritis, and may be a source of re-infection
141
What is BV?
Bacterial (anaerobic) vaginosis
142
In what way is the balance of bacteria inside the vagina disrupted in bacterial vaginosis?
- reduced vaginal lactobacilli
| - increased gardnerella vaginalis and anaerobes
143
What are the signs and symptoms of bacterial vaginosis?
- watery discharge
- positive KOH test (10% KOH - fishy odour)
- clue cells on microscopy
144
What are clue cells?
Epithelial cells of the vagina that get their distinctive stippled appearance by being covered with bacteria - seen in bacterial vaginosis
145
How is bacterial vaginosis treated?
- metronidazole
- amoxicillin
- topical clindamycin
146
What is candidiasis? eg. thrush, balanitis
A fungal infection due to any type of candida (a type of yeast)
147
What factors can cause candidiasis?
- oral contraceptives
- poorly controlled diabetes-
- antibiotics (inhibition of normal flora)
- bowel source
- sexual transmission
148
What are the signs and symptoms of candidiasis? (thrush/balanitis)
- vulval, vaginal and penile erythema - itching and irritation
- thick/adherent discharge, white plaques
- maculopapular and fissuring lesions
149
How is candidiasis diagnosed?
- clinical
| - microscopy (10% KOH) and/or culture
150
Which candida causes 80-90% of cases of candidiasis?
Candida albicans
151
How is uncomplicated candidiasis treated? (C. albicans, not recurrent, not severe)
- topical agents eg. clo-trimazole (Canesten)
| - fluconazole: single 150mg oral dose
152
How is complicated candidiasis treated?
- treatment for 10-14 days (topical or oral)
- obtain in vitro sensitivities
- consider treatment of partner(s)
- long-term suppressive treatment if frequent recurrence
153
AIDS was first recognised in the US how and in what year?
1981
- unexplained opportunistic infections, including pneumocystis jirovecii pneumonia (PcP) and Kaposi's syndrome in homosexual men
- loss of CD4 lymphocytes/immunosuppression
154
HIV is what type of virus?
Retrovirus - possesses reverse transcriptase
155
What is the role of RNA dependent DNA polymerase in HIV?
Converts viral RNA into linear ds DNA
| - subsequently incorporated into host genome
156
Formation of DNA from RNA in HIV is error prone. What does this mean?
High rate of mutability
157
What do the different characteristics of the HIV virus allow it to do?
- RNA-based = survival advantage, great genetic diversity
- DNA intermediary = latency and can incorporate into host genome
- CD4/macrophage tropic = reduction of host immune response
158
What are the routes of HIV transmission?
- sexual-transmission at genital or colonic mucosa
- exposure to infected fluids (blood/blood products), including accidental occupational exposure
- mother to infant
159
Describe the process of HIV viral entry and incorporation into genome
- viral glycoprotein gp120 interacts with cellular receptor CD4 and chemokine receptor CCR5 for virion to gain host cell entry
- reverse transcription occurs in the cytoplasm
- dsDNA imported into nucleus = integration into cell genome, and latency/immune evasion
160
Which glycoprotein on HIV is important for viral entry into the host cell?
gp120
161
Which receptors on the host cell are important for HIV entry into the cell?
- CD4 cellular receptor
| - CCR5 chemokine receptor
162
dsDNA from HIV is imported into the host cell nucleus. What advantages does this have for the virus?
- integration into cell genome
| - latency and immune evasion
163
What is there a loss of in HIV infection?
CD4+ve T cells
164
What does the depletion of CD4+ve T cells in HIV allow?
Opportunistic infections = organisms not normally pathogenic in immune competent patients
- risk of different infections related to degree of immune suppression (CD4 count)
165
In HIV, there is rapid emergence of viral mutants. What does this result in?
- may promote immune evasion
| - drug resistance
166
What are the clinical effects of HIV infection?
Very wide range from asymptomatic carriage to life-threatening opportunistic infection
Either directly due to virus or indirectly due to opportunistic infection/malignancy
167
The WHO classification of HIV is based on what?
CD4 cell count
168
Describe the classification system for HIV
```
stage 1 = less than 500 cells/μL
stage 2 = 349-499
stage 3 = 200-349
stage 4 (AIDS) = less than 200
```
169
AIDS is defined as having a CD4+ T cells count of what?
Less than 200 cells/μL
170
What is acute retroviral syndrome?
```
Occurs in primary HIV infection
- fever
- pharyngitis
- lymphadenopathy
- rash
etc.
```
171
What are the early symptomatic signs of HIV?
- pulmonary TB
- persistent oral candidiasis
- unexplained chronic diarrhoea for more than 1 month
- unexplained persistent fever over 37.6 for more than one month
- severe bacterial infections eg. S pneumoniae bacteraemia
172
What should you do in all new TB cases?
Consider HIV test
173
What are some of the opportunistic infections/conditions that occur in AIDS?
- HIV wasting syndrome, HIV encephalopathy
- oesophageal candidiasis
- pneumocystis jirovecii penumonia
- CMV disease
- CNS toxoplasmosis
- progressive multifocal leukoencephalopathy (PML)
- extra-pulmonary cryptococcosis
- disseminated non-tuberculosis mycobacterial disease-
- extra-pulmonary tuberculosis
- chronic cryptosporidiosis; chronic isosporiasis
- Kaposi's sarcoma
- lymphoma (cerebral or non-Hodgkin's)
174
How do undiagnosed cases of HIV affect transmission?
- 25% of cases in UK undiagnosed
- account for approximately 70% of transmission
- new case rates doubled in past 10 years
175
When should you suspect HIV?
- in the case of risk factors
| - unusual/recurrent/recalcitrant infections
176
How is HIV diagnosed?
- antibody testing (sero-conversion) - confirm with second sample
- PCR
- CD4 cell count
177
Why is PCR used in diagnosing HIV?
- detects viral nucleic acid
- quantitative: viral copy numbers "viral loads" in blood and other fluids
- genotypic mutations conferring drug resistance
178
Which different drugs are used in HIV treatment? (that target critical steps in viral replication cycle)
- nucleoside/nucleotide reverse transcriptase inhibitors eg. zidovudine, lamivudine
- non-nuceloside reverse transcriptase inhibitors eg. efavirenz
- protease inhibitors eg. ritonavir, saquinavir
- viral entry inhibitors
- integrase strand transfer inhibitors
179
Why are combinations of drugs used in HIV?
- to prevent resistance mutations emerging
Be careful of drug interactions and side effects
180
What is HAART?
Highly active antiretroviral therapy
