7. Poorly or Non Gram staining
Acid Fast
Obligate
intracellular
Poorly
gram
staining
No
Peptidoglycan
Mycobacteria •Rickettsia
•Chlamydia
Legionella Mycoplasma
9. Virology:
It is the study of viruses regarding their
structure and diseases caused by them.
Viruses are classified as
1. DNA viruses
a. Hepadnaviruses e.g. Hepatitis B virus.
b. Herpesviruses. e.g. Herpes simplex, zoster.
c. Poxviruses. e.g. Smallpox virus
2. RNA viruses
a. Picornaviruses. e.g. Polio virus, Hepatitis A
virus.
b. Caliciviruses. e.g. hepatitis E virus
10. c. Flaviviruses e.g. Hepatitis C virus.
d. Retroviruses. e.g HIV virus.
e. Paramyxoviruses. e.g. measles, mumps
f. Rhabdoviruses
g. Deltavirus. e.g. HDV
h. Filoviruses. e.g. Ebola virus
11. Parasitology:
It is the study of structure of parasites
and diseases caused by parasites.
Parasites occur in two distinct forms:
single-celled protozoa and multicellular
metazoa called helminths or worms.
12. Host:
A host is an organism that harbors a
microorganism.
A host can be
1. Primary host
2. Secondary host.
A primary host or definitive host is a host in
which the parasite reaches maturity and, if
possible, reproduces sexually.
13. A secondary host or intermediate
host is a host that harbors the parasite
only for a short transition period,
during which (usually) some
developmental stage is completed.
A reservoir host or reservoir can
harbour a pathogen indefinitely with no
ill effects.
A single reservoir host may be
reinfected several times.
