1. Virology
Dr Sadia Ikram

2. Differences Between Viruses & Bacteria
Property
Viruses
Cells
Type of nucleic acid
DNA or RNA but not both
DNA and RNA
Proteins
Few
Many
Lipoprotein membrane
Envelope present in some viruses
Cell membrane present in all cells
Ribosomes
Absent
Present
Mitochondria
Present in eukaryotic cells
Enzymes
None or few
Multiplication by binary fission or mitosis No
Yes

3. Viruses must reproduce within cells.
Cannot generate energy or synthesize proteins.
Reproduce only within cells (obligate intracellular parasites).
Bacteria: obligate intracellular parasites chlamydiae and rickettsiae.
Cannot synthesize sufficient energy to replicate independently.

5. DNA Viruses

6. RNA Viruses

7. Viral replication

8. Pathogenesis Four main effects of virus infection on cell: (1) death.
(2) Fusion of cells to form multinucleated cells.
(3) Malignant transformation.
(4) No apparent morphologic or functional change.

9. Stages of a typical viral infection:
Incubation period: Patient asymptomatic.
Prodromal period: Nonspecific symptoms:
Specific-illness period: Characteristic symptoms and signs occur.
Recovery period: Illness wanes &patient regains good health.
In some patients, the infection persists and a chronic carrier state or a latent infection occur.

10. Laboratory Diagnosis Five approaches to diagnosis of viral diseases:
(1) identification of the virus in cell culture.
(2) microscopic identification directly in the specimen.
(3) serologic procedures to detect a rise in antibody titer or the presence of IgM antibody.
(4) detection of viral antigens in blood or body fluids.
(5) detection of viral nucleic acids in blood or patient's cells.

11. Microscopic Identification
Inclusion bodies.
Multinucleated giant cells.
Serologic Procedures
Presence of IgM: Diagnose current infection.
Presence of IgG: Diagnose chronic infection

12. Major Viral Pathogens Structure Viruses DNA enveloped viruses
Herpesviruses (herpes simplex virus types 1 and 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human herpesvirus 8), hepatitis B virus, smallpox virus
DNA nucleocapsid viruses
Adenovirus, papillomaviruses, parvovirus B19
RNA enveloped viruses
Influenza virus, parainfluenza virus, respiratory syncytial virus, measles virus, mumps virus, rubella virus, rabies virus, human T-cell lymphotropic virus, human immunodeficiency virus, hepatitis C virus
RNA nucleocapsid viruses
Enteroviruses (poliovirus, coxsackievirus, echovirus, hepatitis A virus), rhinovirus, rotavirus, Norwalk virus, hepatitis E virus

13. Hepatitis Viruses
Five medically important viruses "hepatitis viruses" because their main site of infection is liver.
Hepatitis A virus (HAV). ( Infectious hepatitis)
Hepatitis B virus (HBV).
Hepatitis C virus (HCV).
Hepatitis D virus (HDV, delta virus).
Hepatitis E virus (HEV).
Epstein-Barr virus (the cause of infectious mononucleosis), cytomegalovirus, and yellow fever virus, infect liver and other sites in body and therefore not exclusively hepatitis viruses.

14. Hepatitis Viruses Virus Mode of Transmission Laboratory Diagnosis
Vaccine
Hepatitis A Virus
Fecal-oral
IgM HAV
Yes
Hepatitis B Virus
Blood, sexual, at birth
HBsAg, HBsAb, IgM.
Hepatitis C Virus
Blood, sexual
HCV Ab No
Hepatitis D Virus
Ab to delta Ag
Hepatitis E Virus
None

15. Human Tumour viruses:
Human T-cell lymphotropic virus: causing leukemias and lymphomas.
Human papillomavirus: causing papillomas and squamous cell carcinomas.
Epstein-Barr Virus: causing nasopharyngeal carcinoma.
Hepatitis C Virus: causing hepatocellular carcinoma.

16. PARASITOLOGY
Dr. SADIA IKRAM

17. What is Parasite and Parasitism
A parasite is an organism that in lives and infects other living thing (host) and obtain shelter and nourishment from it.
PARASITISM
A form of symbiosis in which one organism (called parasite) benefits at the expense of another organism usually of different species(called host).

18. Definitions
Host: “the organism in, or on, which the parasite lives and causes harm”
Definitive host: “the organism in which the adult or sexually mature stage of the parasite lives.”
Intermediate host: “the organism in which the parasite lives during a period of its development only. i.e. Asexual, immature form of parasite.”
Zoonosis: “a parasitic disease in which an animal is normally the host - and the parasite also infects man”
Vector: “a living carrier (e.g. an arthropod) that transports a pathogenic organism from an infected to a non-infected host”. A typical example is the female Anopheles mosquito that transmits malaria.

19. INTRODUCTION TO BASIC PARASITOLOGY
Parasites are Eukaryotes.
Two major groups:
Protozoa (unicellular)
Metozoa/Helminth (Multicellular) or worms

20. Important Groups of Human Parasites
Protozoa
Amoeba
Flagellate
Sporozoa
Ciliate
Helminthes
Platyheminthes
Trematodes
Cestodes
Nematodes
Arthropoda
Mosquito
Fly
Tick
Mite
Bug
Flea
Lice

21. CLASSIFICATION of HELMINTHS
Platyhelminthes
Flatworms are flattened, hermaphroditic, with a few exceptions
Subdivided in to Two classes:
Cestoda (tapeworms) &Trematoda (flukes).
Cestodes, or tapeworms
Taenia solium, Echinococcus granulosus.
II. Trematoda (flukes)
Fasciola hepatica, Clonorchis sinensis, Schistosoma spp.
Fascioloa hepatica
Taenia saginata

22. CLASSIFICATION of HELMINTHS
b. Nematoda (roundworms)
Elongated , round and un-segmented.
Most human infections-ingestion of egg or larva.
Examples Ascaris lumbricoides, Ankylostoma duodenale, Enterobius vermiculoaris etc

23. Clinical Classification of Protozoa
Intestinal
Entamoeba histolytica (Amoebiasis)
Giardia lamblia (Giardiasis)
Balantidium coli (Opportunistic infections)
Isospora belli
Cryptosporidium
Vaginal
Trichomonas vaginalis (Viginal infections)
Blood –
Plasmodium (Malaria)
Leishmania (Kala Azar)
Trypanosoma (Sleeping sickness)
Tissue
Toxoplasma gondii (Toxoplasmosis)

24. Direct Life Cycle Direct Life cycle Only humans are host
Infective stage like ovum, cyst, larva passed out of body that infect healthy person.
Example E histolytica, Giardia, Ascaris lumbricoides.

25. Indirect Life Cycle Indirect Life cycle
Multiple hosts or involvement of vector.
Definitive host, Intermediate host.
Example Taenia saginata spp, Schistosoma spp etc
Life cycle of Taenia saginata

26. Infective and Diagnostic stage
Forms or stages of a parasite:
Diagnostic Stage:
Trophozoite: (active feeding, vegetative stage of a protozoal parasite).
Infective Stage:
Cyst/ oocyst: (inactive, dormant with protective thick wall, infective form).

27. Laboratory Diagnosis & Treatment
Stool Examination
Serology
ELISA
PCR
Albendazole & Mebendazole.