1. Tropical Medicine- Parasitic Infections Goldsmid

Question 1

Infectious agents are characterised into what categories?

Answer 1

Viruses
Rickettsiae and chlamydia
Bacteria
Fungi
Parasites: PROTOZOA, HELMINTHES, ARTHROPODS

Question 2

What are the properties of a virus?

Answer 2

No cell wall/cell body
DNA or RNA
No metabolic enzymes
Classify the viral infections by organs involved*

Question 3

What viruses commonly cause respiratory infection?

Answer 3

Influenza
Rotavirus
Adenovirus
Coronavirus
Rhinovirus
SARS virus

Question 4

What viruses commonly cause GIT infection?

Answer 4

Rota viruses
Norovirus
Reoviruses

Question 5

What viruses cause liver infection?

Answer 5

Hep A
Hep B
Hep C
Deltavirus
Hep E virus

Question 6

Arborviruses (arthropod bourne viruses- eg mosquitoes mainly) cause distinctive pathologies- name some viruses and what they cause

Answer 6

Dengue Viruses- Mosquitoes
Ross River Virus - Mosquitoes
Yello Fever Virus - Mosquitoes
Japanese encephalitis - mosquitoes
Tick-borne encephalitis virus – Ixodid ticks (Tics are widespread in tropical areas – important)
Sandfly fever virus – Phlebotomus sandflies

Question 7

There are haemorrhagic Viruses

Answer 7

Many newly recognised/emerged types:
o	Marburg virus
o	Ebola virus
o	Hendra virus
o	Hanta virus

Question 8

Common Miscellaneous Viruses

Answer 8

• HIV virus
• Epstein Barr virus
• CMV
• Rabies/Lyssa virus
• Papilloma viruses
• Orf virus
• Smallpox virus
• Rubella
• Chickenpox

Question 9

What are the properties of bacteria?

Answer 9

Prokaryotes (no nuclear membrane, no organelles in the cytoplasm except ribosomes)
No discrete nucleus
Mucopeptide Cell wall (muramic acid- target site for abx)
Metabolic Enzyme systems

Question 10

Name common GRAM POSITIVE rods

Answer 10

• Anthrax
• Clostridium
• Corynebacterium listeria
• Mycobacterium

Question 11

Name common GRAM POSITIVE cocci

Answer 11

Staph

Strep

Question 12

Name common GRAM NEGATIVE rods (bacilli)

Answer 12

= peptidoglycan wall, mainly GIT organisms
E coli
Shigella
Salmonella
Proteus
Pseudomonas
Klebsiella
Yersinia
Burkholderia
Vibrios
Haemophilus
Brucella

Question 13

Name common GRAM NEGATIVE cocci

Answer 13

• Meningococci
• Gonococci
• Spirochaetes

Question 14

3 common bacteria cannot be classified via this system, what are they?

Answer 14

• Rickettsia spp ((Cell wall deficiency or they have no cell wall))
• Chlamydia spp
• Mycoplasma sp

Question 15

How do we classify FUNGI?

Answer 15

Filamentous::: Dermatophytes – Aspergillus

Yeasts – Candida, Cryptococcus

Dimorphic: Blastomycosis

Question 16

What are PARASITES?

Answer 16

Animal organisms – eukaryote cell structure

Can be single celled (protozoa) or multicellular (helminths, arthropods)

Because they are similar to us, it is difficult to treat

Question 17

How do we classify PARASITES?

Answer 17

1. Protozoa
2. Metazoa (multicellular)
   - Helminths
   - Arthropods

Question 18

What are the types of life cycle for a PARASITE?

Answer 18

With parasitic infections, a knowledge of the life cycle is essential to understand the epidemiology, clinical course of the infection & to plan control measures.
TYPES:
- Direct – host A carries infection & passes it onto host A
- Indirect – goes from host A to host B (ie human to mosquito!), back to host A

Question 19

What are the STAGES of a life cycle of a parasite?

Answer 19

In the life cycle: you can identify the definitive host, the intermediate host and/or vector (carrier), the infective stage (infects humans) & the diagnostic stage/s of the parasite.

Question 20

What are PROTOZOA parasites, and how do we classify them?

Answer 20

Single celled eukaryotes, classified by LOCOMOTION

1. Flagellates- hair like flagellae used
2. Ciliates- small brush like structure
3. Sarcodonia (amoebae) - pseudopodia allow them to flow in that direction
4. Sporozoa- no organs of movement at all!

Question 21

what kinds of infections can protozoa cause?

Answer 21

Intestinal
Blood Bourne
Tissue Infections
Atrial infections

Question 22

Protozoan infections- intestinal

Answer 22

Amoebiasis
Blastocytosis
Balanidiasis
Isosporiasis

Question 23

Protozoan infections: blood borne

Answer 23

Malaria (Plasmodium spp)
African Sleeping Sickness
Chaga’s Disease (Trypanosoma cruzi)
Kala azar (black fever)

Question 24

Protozoan infections: tissue infections

Answer 24

Toxoplasmosis

Cutaneous leishmaniasis

Question 25

Protozoan infections: atrial infections

Answer 25

Trichomoniasis

Question 26

HELMINTHS(worms) are a type of METAZOA (parasite)

Answer 26

.

Question 27

Platyhelminths are a type of Metazoa, what do they cause?

Answer 27

``` Flat worms (dorsoventrally flattened) Includes the trematodes (flukes) & cestodes (tapeworms) ```

Question 28

What is a trematode?

Answer 28

Type of Platyhelminth (Metazoa parasite) which is unsegmented, mostly Dorsoventrally flattened No body gavity but do have a gut Mostly hermaphrodite All have a life cycle involving a snail intermediate host o Important species → : Liver fluke (Fasciola hepatica) – endemic in aus : Blood flukes (Schistosoma spp) o Other species of note include: • Chinese liver fluke (Clonorchis sinensis) • Intestinal fluke (Fasciola buski) • Lung fluke (Paragonimus spp)

Question 29

What is a cestode?

Answer 29

TAPEWORM, type of platyhelinth (metazoa parasite) Adult tapeworms are segmented with a scolex for attachment Have NO GUT Hermaphrodite NO body Cavity Form larvae cystercerci or hydatid cysts o Important tapeworms include → :Beef tapeworm – Taenia saginata (endemic in Aus) :Pork tapeworm – Taenia solium :Hydatid tapeworm - Echinococcus granulosus o Other species of note: • Dwarf tapeworm = rodentolepis nana (endemic in Australia

Question 30

What are nematodes?

Answer 30

ROUND tapeworm, platyhelinth (metazoan parasite) Round in transverse section Have both gut & body cavity Usually separate male & female worms Important species of intestinal nematodes (all endemic in Aus) include: ::Ascaris lumbricoides – Intestinal roundworm ::Trichuris trichiura – Whip worm ::Ancylostoma duodenale – Hookworm :: Necator americanus – Hookworm :: Enterobius vermicularis – Thread/Pin worm :: Strongyloides stercoralis • Other species of note: o Dog/cat hookworms - Cutaneous larva migrans o Dog/cat ascarids (Toxocara spp) – Visceral larva migrans o Trichina worms (Trichinella spp) – Trichinosis (endemic in Tas) o Filarial infections (esp Wuchereria bancrofti) - Lymphatic filariasis

Question 31

What are the properties of insects?

Answer 31

Adult insects have a head, thorax, abdomen and 6 legs. Important insects include: -Human lice - Myiasis - Jigger fleas Other species include mosquitoes & fleas which are important vectors of disease. Some insects may be of importance due to being poisonous or due to bites/stings Hymenoptera (one of the largest orders of insects) • Bees • Wasps • Ants

Question 32

What are arachnadia?

Answer 32

• Have a body in 2 parts. The cephalothorax & the abdomen Have 8 legs Include the following arthropods: Acarina, spiders, scorpians

Question 33

Lists some acarina

Answer 33

``` (mites and ticks) • Scabies mite (Sarcoptes scabiei) • Tcks as cause of disease – tick paralysis • Ticks as vectors of disease o Spotted fevers o Tick-borne encephalitis ```