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Flashcards in 1. Tropical Medicine- Parasitic Infections Goldsmid Deck (33):
1

Infectious agents are characterised into what categories?


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

2

What are the properties of a virus?

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

3

What viruses commonly cause respiratory infection?

Influenza
Rotavirus
Adenovirus
Coronavirus
Rhinovirus
SARS virus

4

What viruses commonly cause GIT infection?

Rota viruses
Norovirus
Reoviruses

5

What viruses cause liver infection?

Hep A
Hep B
Hep C
Deltavirus
Hep E virus

6

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

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

7

There are haemorrhagic Viruses

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

8

Common Miscellaneous Viruses

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

9

What are the properties of bacteria?

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

10

Name common GRAM POSITIVE rods

• Anthrax
• Clostridium
• Corynebacterium listeria
• Mycobacterium

11

Name common GRAM POSITIVE cocci

Staph
Strep

12

Name common GRAM NEGATIVE rods (bacilli)

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

13

Name common GRAM NEGATIVE cocci

• Meningococci
• Gonococci
• Spirochaetes

14

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

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

15

How do we classify FUNGI?

Filamentous::: Dermatophytes – Aspergillus

Yeasts – Candida, Cryptococcus

Dimorphic: Blastomycosis

16

What are PARASITES?

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

17

How do we classify PARASITES?

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

18

What are the types of life cycle for a PARASITE?

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

19

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

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.

20

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

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!


21

what kinds of infections can protozoa cause?

Intestinal
Blood Bourne
Tissue Infections
Atrial infections

22

Protozoan infections- intestinal

Amoebiasis
Blastocytosis
Balanidiasis
Isosporiasis

23

Protozoan infections: blood borne

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

24

Protozoan infections: tissue infections

Toxoplasmosis
Cutaneous leishmaniasis

25

Protozoan infections: atrial infections

Trichomoniasis

26

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

.

27

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

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

28

What is a trematode?

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)

29

What is a cestode?

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

30

What are nematodes?

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

31

What are the properties of insects?

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

32

What are arachnadia?

• Have a body in 2 parts.

The cephalothorax & the abdomen
Have 8 legs
Include the following arthropods: Acarina, spiders, scorpians

33

Lists some acarina

(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