DDT 19 - Opportunistic infections associated with AIDS patients Flashcards
the elements of AIDS
has a confirmed positive HIV test
Immuno-compromised (low T cell count)
Presence of either an opportunistic infection or AIDS related cancer
opportunistic infection definition
Infections that develop as a result of damage to the immune system
They take advantage of the opportunity provided by weakened immune system
T cell subsets
Cytotoxic T-lymphocytes
Helper T-lymphocytes
Suppressor T-lymphocytes
Memory cells
Cytotoxic T-lymphocytes function
recognise and destroy cells w/ foreign antigen and infected cells from the body e.g. viruses, bacteria, fungi and cancer
Helper T lymphocytes function
enhance immune response by releasing interleukin
T helper 1 -interleukin 2 stimulates other T cell
T helper 2 - interleukin 4 - stimulate proliferation of B cells
Suppressor T cell function
said to suppress immune response when there are fewer antigens - release suppressor cytokines
Memory cells
remain in lymphatic tissue long after infection as died for secondary immune response
CD4 cell
a glycoprotein found on the surface of immune
cells such as T helper cells, monocytes, macrophages, and dendritic cells
what type of cell is CD4
white blood cell - fights infection aka T helper cells
where are CD4 cells made
are made in the spleen, lymph nodes, and
thymus gland
purpose of CD4 counr
- indicates the stage of your HIV disease,
- guides treatment, and predicts how your disease may progress.
how are CD4 counts reported
cubic millimeter of blood
normal CD4 count
500 - 1,500 per cubic millimeter of blood
how is CD4 count affected in HIV
HIV disease is progressing if the CD4 count is going down.
This means the immune system is getting weaker and you are more likely to get sick.
In some people, CD4 counts can drop dramatically, even going down to zero.
Stage I of HIV symptoms and CD4 count
No symtoms
Persistent Generalized Lymphadenopathy
>500
Stage II of HIV symptoms and CD4
Cutaneous Manifestation Folliculitis
Dermatomal Herpes Zoster
500 - 350
Stage III of HIV symptoms and CD4 count
Oral Candidiasis,
Oral Hairy Leukoplakia,
Pulmonary Tuberculosis
350-200
Stage IV of HIV symptoms and CD4 count
Kaposi’s Sarcoma (KS), Oral KS MAC, Severe Chronic Herpes Ulcers, Toxoplasmosis, Cryptococcus <200
name the smallest free living organism
mycoplasma species (150-259nm)
describe mycoplasma pneumoniae
no cell wall
does not need host cell for replication
prokaryote
where do we find mycoplasma pneumoniae
mucosal surfaces
exteracellulary in respiratory and urogenital tracts
how if mycoplasma pneumoniae transmitted
M. pneumoniae is transmitted from person-to-person by infected
respiratory droplets during close contact.
incubation period of mycoplasma pneumoniae
3 weeks
when does infection frequently occur
during the fall and winter but may
develop whole-year round.
how does mycoplasma pneumoniae disrupt function of immune system
M. pneumoniae is a superantigen
- activate macrophages and lymphocytes
stimulate cytokine activation.
- can attract inflammatory cells and induce cytokine secretion
streptococcus pneumoniae
gram-positive, oval/lancet-shaped cocci are often arranged in pairs, known
as a diplococcus, or can be present in short chains .
who is most likely to get streptococcus pneumoniae
people under 2 years and people over 60 or inflicted by alcoholism, diabetes mellitus, chronic renal disease or asplenia
how many infant deaths are caused by streptococcus pneumoniae
Globally, it causes approximately 1.2 million infant deaths annually, and its prevalence is especially high in regions of widespread HIV-1 infection.
host range of streptococcus pneumoniae
Humans, mice, rats, guinea pigs, chimpanzees, rhesus monkeys,
and mammals that live in association with humans
mode of transmission of streptococcus pneumoniae
Infectious cells can be disseminated via microaerosol
droplets created by coughing or sneezing, or person-person oral contact.
Transmission is common, but infection is infrequent as healthy individuals carry
S. pneumoniae in the nasopharyngeal region without any presence of infection.
incubation period of streptococcus pneumoniae
1-3 days
another name for treponema pallidum
syphilis
shape of treponema pallidum
Treponemes are helically coiled, corkscrew-shaped cells, 6 to 15 μm long and 0.1 to 0.2 μm wide – a spirochaete
describe membrane of treponema pallidum
• They have an outer membrane which surrounds the periplasmic
flagella, a peptidoglycan-cytoplasmic membrane complex, and a
protoplasmic cylinder
how does treponema pallidum multiply
transverse binary fission
describe weaknesses of treponema pallidum
• a very frail organism that cannot thrive outside
the body and is crippled by simple physical and
chemical elements such as heat, soap, and
water
how do treponema pallidum infect the cells
• Treponemes are highly invasive pathogens which often disseminate relatively soon after inoculation
what causes evasion of host immune response from treponema pallidum
• Evasion of host immune responses appears to be, at least in part, due to the unique structure of the treponemal outer membrane
what feature does treponema pallidum have
Although treponemes lack classical lipopolysaccharide (endotoxin) they possess abundant lipoproteins which induce inflammatory processes
primary syphilis
the infection is usually seen as individual sores in adults around the genitals.
secondary syphilis
the infection presents itself as a general rash all over the body (mostly on the hands and feet).
latent syphilis
‘hidden syphilis’; the disease shows no symptoms but the
organism continues to reproduce
what systems can tertiary syphilis cause damage to?
the disease causes major destruction to the skeletal system, circulatory system, and nervous system (along with other vital organs); eventually results in death.
As seen, if left untreated, syphilis affects the bones, heart, brain, nervous system and other organs of the body
how is congenital syphilis contracted
however, the disease is spread through infection of the
mother to the child through the blood supply to the womb (most common when the mother is in the secondary to latent stages of the disease).
tertiary stage syphilis causes damage to what organs
Tertiary stage syphilis can see damage to the brain, heart, eyes, liver, bones, and joints.
This damage may be serious enough to cause death.
what disease is the fungal pathogen candida albicans responsible for
candidiasis
where does candida albicans reside in the body
as harmless commensals in the gastrointestinal
and genitourinary tract;
who are usually victim to disease when infected with candida albicans
immunocompromised individuals, such as HIV infected victims, transplant recipients, chemotherapy patients, and low birth-weight babies.
3 main forms of disease from candida albicans
oropharyngeal candidiasis,(“thrush“) ;
vulvovaginal candidiasis (yeast infection)
invasive candidiasis.
what organs can the invasive candidiasis infect
a serious infection that can affect the blood, heart, brain, eyes, bones, and other parts of the body.
how common is candida albican in immunocompromised people
top source of fungal
infections in immunocompromised people
transmission of candida albicans
from mother to infant through childbirth, and remains as part of a normal human’s microflora.
The overgrowth of C. albicans leads to symptoms of disease, and it occurs when there are imbalances for example, changes in the normal acidity of the vagina.
rarely through childbirth
how is candida albicans transmitted from people if they are not mother and child
People-to-people acquired infections mostly happen in hospital settings where immunocompromised patients acquire the yeast from healthcare workers
who first described kaposi sarcoma
Dr. Moritz. kaposi in 1872
what virus induces kaposi sarcoma tumour
is caused by the human herpesvirus 8 (HHV-8), an infection more likely to occur in people with compromised immunity, such as people with HIV or taking immunosuppressant drugs for an organ transplant.
describe kaposi sarcoma (KS) tumour
a vascular tumour (it involves blood vessels) that affects soft tissue in multiple areas of the body (it is “multicentric”). It originates from endothelial cells which line blood vessels, and there are four main types of Kaposi sarcoma (KS):
classic KS
also known as Mediterranean Kaposi sarcoma, a rare tumor that more often affects older males
epidemic KS
the most common form of KS, also known as
AIDS-associated Kaposi sarcoma
Endemic KS
also known as African Kaposi sarcoma, this
form is relatively common in equatorial Africa and can affect children and adults independently of HIV infection
latrogenic KS
also known as immunosuppressive
treatment-related Kaposi sarcoma, immunosuppressive Kaposi
sarcoma or transplant-related Kaposi sarcoma.
how is Kaposi sarcoma more likely to be transmitted to compromised immunity people
tumour is caused by human herpesvirus infection which can be spread both sexually and non-sexually
symptoms of kaposi sarcoma
cutaneous lesions, marks on the skin that are;
brown, purple, pink, red macules
merge into plaques and nodules - lead to blue-violet to black
sometimes show edema
people who are at a risk of human herpes virus 8 and thus getting kaposi sarcoma
people with HIV and have a CD4 cell count of less than 200 are high risk of kaposi sarcoma
what type of people are prone to get human herpes 8 and then kaposi sarcoma
- organ transplant recipients taking immunosuppressant drugs to suppress rejection of the organ, for example
2nd most common cancer in women worldwide
cervical cancer
what virus must be acquired before the development of cervical cancer occurs
human papillomavirus DNA
HPV
types of epithelial cells HPV will infect
skin
anogenital mucosa
oropharyngeal mucosa
describe HPV
• HPV is a heterogeneous group of viruses that contain closed circular double-stranded DNA.
Studies have shown a higher prevalence of 1.___ in HIV- 2.____ women than in 3.____ women, and
the 4.___ prevalence was directly proportional to the
severity of 5.___ as measured by 6.___
- HPV
- Seropositive
- seronegative
4, HPV - immunosuppression
- CD4 count
what is said to enhance latent or subclinical HPV activity
Impaired lymphocyte function has been postulated to enhance latent or subclinical HPV activity, resulting in a higher rate of persistent infection.
what part of the body does non-hodgkins lymphoma originate
lymphatic system and develop from lymphocytes B crlls
causes of non-hodgkins lymphoma
body produces too many abnormal lymphocytes
lymphpocytes don’t die and get replaced by new ones they continue to grow and divide - leads to crowding and swelling
how does non hodgkins lymphoma arise in Bcells
. Most non-Hodgkin’s lymphoma arises from B cells.
Subtypes of non-Hodgkin’s lymphoma that involve B cells include diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma and Burkitt lymphoma.
name the 2 types of non-hodgkins lymphoma that begin in T cels and often does it occur
Non-Hodgkin’s lymphoma occurs less often in T cells.
Subtypes of non-Hodgkin’s lymphoma that involve T cells include peripheral T-cell lymphoma and cutaneous T-cell lymphoma
factors that can increase risk of non-hodgkins lymphoma
medications that suppress immune e.g. for organ transplant
infection of certain viruses and bacteria e.g. HIV and Epstein-Barr virus
chemicals e.g. used to kill insects and weeds
older age (60s and older)
non-hodgkins lymphoma symptoms
Painless, swollen lymph nodes in your neck, armpits or groin.
• Abdominal pain or swelling.
• Chest pain, coughing or trouble breathing.
• Fatigue.
• Fever.
• Night sweats.
• Weight loss.
