Immunologically the most significant surface proteins

Immunologically, the most
significant surface
proteins include
hemagglutinin (H) and
neuraminidase (N).
Hemagglutinin and
neuraminidase are critical
for virulence, and they
are major targets for the
neutralizing antibodies of
acquired immunity to
influenza. Hemagglutinin
binds to respiratory
epithelial cells, allowing
cellular infection.
Neuraminidase cleaves
the bond that holds newly
replicated virions to the
cell surface, permitting
the infection to spread.
Uncomplicated influenza illness
typically resolves after 3—7
days for the majority of persons,
although cough and malaise can
persist for >2 weeks. However,
influenza virus infections can
cause primary influenza viral
pneumonia; exacerbate
underlying medical conditions
(e.g., pulmonary or cardiac
disease), lead to secondary
bacterial pneumonia, sinusitis,
or otitis media; or contribute to
coinfections with other viral or
bacterial pathogens. Influenza
virus infection also has been
uncommonly associated with
encephalopathy, transverse
myelitis, myositis, myocarditis,
pericarditis, and Reye syndrome
Measles Prodrome of fever
(as high as 105),
malaise, cough,
coryza, and
conjunctivitis (the
three c’s), a
pathognomic
exanthema (koplik
spots), followed by a
The cause of measles is
the measles virus, a
single-stranded, negative-
sense enveloped RNA
virus of the genus
Morbillivirus within the
family Paramyxoviridae.
Patient is contagious from 4
days before the rash appears
until 4 days after the rash
appears. Some
immunocompromised patients
do not develop the rash. Acute
encephalitis can occur. Otitis
media, bronchopneumonia,
laryngotracheobronchitis, and

maculopapular rash,
Rash appears about
14 days after
exposure. The rash
spreads from the
head to the trunk t
the lower extremities.
diarrhea.

One out of every 1,000
measles cases will
develop acute
encephalitis, which often
results in permanent
brain damage.

One or two out of every
1,000 children who
become infected with
measles will die from
respiratory and
neurologic complications.
Subacute sclerosing
panencephalitis (SSPE) is a
rare, but fatal degenerative
disease of the central nervous
system characterized by
behavioral and intellectual
deterioration and seizures that
generally develop 7 to 10 years
after measles infection.
c. Analyze the HIV viral structure, the process by which it infects the CD4 cells and viral
replication and describe:
HIV belongs to a group of retroviruses called lentiviruses. The genome of retroviruses is made
of RNA (ribonucleic acid), and each virus has two single chains of RNA; for replication, the
virus needs a host cell, and the RNA must first be transcribed into DNA (deoxyribonucleic acid),
which is done with the enzyme reverse transcriptase. HIV infects mainly the CD4+ lymphocytes
(T cells), but also to a lesser degree monocytes, macrophages, and dendritic cells (these cells
are also CD4+ cells). Once infected, the cell turns into an HIV-replicating cell and loses its
function in the human immune system. Like other viruses, HIV does not have a cell wall or a
nucleus. The basic structure of the virus is as follows: