RNA Viruses- overview, HIV, HTLV 1 and 2

to refer to bacteria we often use the

genus and species names

to refer to viruses we refer to the

family and species names

retroviridae encodes for ____

reverse transcriptase enzyme

Aids was identified in

1981

HIV 1 identified in

1983

HIV2 identified in

1986

HIV epidemics resulted from

simian-to-human transmission

retroviridae receptor sites

CD4 receptors

CCR5 and CXCR4 coreceptors
CD4 positive cells

Stages of HIV replication/ pathology

1. Binding

2. Fusion

3. Reverse Transcription

4. Integration

5. Replication

6. Assembly

7. Budding

Step one of HIV replication and pathology

Fusion of HIV to the host cell surface

step 2 of hiv replication and pathology

hiv rna reverse transcriptase, integrase and other viral proteins enter the host cell

step 3 of hiv replication and pathology

viral dna is formed by reverse transcription

step 4 of hiv replication and pathology

viral dna is transported across the nucleus and integrates into the host dna

step 5 of hiv replication and pathology

new viral rna is used as genomic rna and to make viral proteins

step 6 of hiv replication and pathology

new viral rna and proteins move to the cell surface and a new immature hiv forms

step 7 of hiv replication and pathology

virus is released- viral protease cleaves new polyproteins to create mature infectious virus.

clinical stages of hiv 1 and 2

acute infection

clinical latency

acquired immunodeficiency disease (AIDS)

acute infection of hiv characteristics

2-4 weeks after infection

flu like symptoms that usually subside

patients are unaware of the severity of the disease

antibody tests are negative for hiv

clinical latency stage of hiv characteristics

asymptomatic

reproduction of the virus is low

length of stage is dependent on age/ health of patient

acquired immunodeficiency disease stage of hiv characteristics

severe

CD4+ cell count decreased below 200 cells/ mm

immunocompromised and cannot fight infections if any arise

HIV infection has __ stages

5

stage 0 of hiv infection

negative test within 6 months of first positive test

stages 1-2 of hiv infection are determined by

CD4 count

stage 3 of hiv infection is defined by

defined by opportunistic illness diagnosis and a CD4 count below <200 cells/ uL in adults.

CD4 count of stage 1 hiv positive adults

more or equal to 500 cells/uL

CD4 count of stage 2 hiv positive adults

200-499

drug treatments for hiv

inhibiting viral enzymes

inhibiting fusion

inhibiting viral translation

anti-retroviral therapy

prevention of hiv

behavior modification

PrEP

Human T-cell Leukemia Virus 1 (HTLV1)

15-20 million infections worldwide

endemic to Japan, Caribbean, sub-Saharan Africa, Center & South America, Middle East

Associated with T cell Leukemia

HTLV-1 associated myelopathy/tropical spastic paraparesis

HTLV1 associated t cell leukemia

severe malignant lymphoproliferative disease of CD4+ cells

CD3, CD4, CD25, and lymphocytes have cleaved nuclei

HAM/TSP

muscle weakness in legs, sensory disturbances (impacts nervous system), urinary impotence, back pain/spasms

derived from spinal cord damage

HLTV2

endemic to pygmy tribes in central america

no malignancies resembling HAM/TSP

95% of infections are asymptomatic but there is an increase in associated bacterial infections

HTLV1 and 2

transmitted sexually, vertically, through IV drug use, transfusions

no vaccines available

few drug options available