Microbiology Hot topics from the tropics Flashcards Preview

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Flashcards in Microbiology Hot topics from the tropics Deck (42)
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1
Q

Parasites infecting man can be subdividided as follows:

A

o Single cell parasites – Protozoa e.g. malaria, giardia
o Multicellular parasites – Metazoa e.g. helminths
o Ectoparasites e.g. fleas and lice

2
Q

Malaria: A disease caused by

A

The malaria parasite – a protozoan

3
Q

Malaria: Incidence

A

> 300 million people infected with malaria per year

4
Q

Malaria: Mortality

A

> 1 million deaths from malaria per year – mainly affects children <5 years of age

5
Q

Malaria: Geographical locations

A

equator

6
Q

Malaria: Human forms of Malaria

A

There are 4 types of malaria that affect humans:
• Plasmodium vivax
• Plasmodium falciparum – severe malaria (cerebral/anaemia etc)
• Plasmodium ovale
• Plasmodium malariae

7
Q

Malaria: Onset

A

7-30 days after mosquito bite depending on the species (pre-patent period (life cycle takes awhile)

8
Q

Malaria: P. vivax incubation

A

May rarely take up to 1 year

9
Q

Malaria: P.vovax and P.ovale can also exist

A

As dormant forms (hyponozoites) that produce relapses months or years later

10
Q

Malaria: Life cycle (see more)

A
  1. Mosquito bites host (female for eggs to mature)
  2. Injects anticoagulant to prevent blood clotting + saliva (and if she is
  3. Sporozoytes (15-20 min) travel to liver
  4. Undergo life cycle (1 week) – infect RBC (multiplied by binary fission)
  5. Once RBC infected = brittle/ less malleable in capillaries + surface changes causing sticking to blood vessels.
  6. Burse and release exponential increase in infected RBC’s
11
Q

Malaria: Presenting Features/ Complication of Malaria

A
Flu-like symptoms
Respiratory symptoms
GI symptoms
CNS symptoms
Other
12
Q

Malaria:Flu-like symptoms

A
Fever
Rigors
Sweats
Malaise
Myalgia
13
Q

Malaria: Respiratory symptoms

A

Cough
Respiratory distress
Pulmonary oedema

14
Q

Malaria: GI symptoms

A
Nausea
Vomiting
Diarrhoea
Jaundice
Liver failure
15
Q

Malaria:CNS symptoms

A

Headaches
Confusion
Coma – cerebral malaria

16
Q

Malaria: Other

A
Shock
Acidosis
Renal impairment
“Blackwater fever”
Anaemia
DIC
Hypoglycaemia
Splenic rupture
17
Q

Malaria: Management of Malaria

A
  1. Antimalarials e.g. quinine*, doxycycline, fansidar, primaquine (See BNF, HTD)
  2. Supportive therapy – correct shock, anaemia, bleeding abnormality, treat or prevent convulsions, hypoglycaemia, (incurrent infections)
  3. Avoid over hydration
  4. Consider exchange transfusions
18
Q

Malaria: Methods of preventing Malaria

A
Protection against bites
•	Bed nets
•	Insect repellants
•	Clothing to avoid bites at dusk and dawn
•	Screens on doors and windowns
Protection against infections
•	Prophylaxis
•	Future role of immunisation
Prevent parasite life cycle:
•	Prompt effective treatment in endemic areas
•	Local measure e.g. pesticides, avoid pooling of water
Potential role for Altruistic vaccine
19
Q

Investigations

A
•	If you suspect VHF, do a malaria film only
•	Thick and thin malaria films
→ Thick – looking at structure of RBC’s
•	Malaria antigen test
•	FBC – decreased platelets
•	Clotting screen
•	U and Es, LFTs
•	Blood cultures
•	Serology – e.g. dengue fever
•	pH
•	Lactate
20
Q

Results

A

WCC – depressed in malaria
Clotting screen – disseminated vascular
Blood cultures – intercurrent infections
Serology – other

21
Q

Viral Haemorrhagic Fevers → Types

A

Lassa
Marburg
Ebola
CCHf

22
Q

Viral Haemorrhagic Fevers → Risk Factors

A
  • Travel to high risk area in the last 21 days
  • Contact with human or animal with suspected VHF (body fluids/tissues)
  • Injestion of bush meat
23
Q

Viral Haemorrhagic Fevers → Description

A

Febrile disease caused in a variety of ways

24
Q

Leishmaniasis

A

Several types of leishmaniasis broadly categorised info:
Visceral leishmaniasis
Cutaneous leishmaniasis

25
Q

Visceral leishmaniasis is characterised by

A

Hepatosplenomegaly

26
Q

Cutaneous leishmaniasis

A

Tropical sores

27
Q

Transmission

A

Sandflies

28
Q

Diagnosis

A

Biopsy

29
Q

Treatment

A

Antimonials
Pentamidine
Amphotericin

30
Q

Prevention

A

Impregnanted bed nets

Elimination of animal vector e.g. dog control

31
Q

Description (2 types)

A
Sleeping sickness (Africa)
Chagas disease (S. America)
32
Q

Transmission of Sleeping sickness

A

Tsetse fly transmit from wild animals to man

33
Q

Chagas disease transmission causes

A

Rejuvid blood transmits to man causing (if it gets to this stage its irreversible):

  1. megaoesophagus
  2. Megacolon
  3. Cardiomyopathy
34
Q

Treatment

A

Arsenicals

35
Q

Transmission of helminths:

A

ingestion

Inoculation

36
Q

ingestion

A
  • Of eggs ir larvae from the faeces of an infected host e.g. threadworm
  • Of soil or food contaminared by soil in which larvae have developed from eggs passed in the faeces have developed from eggs passed in the faeces of an infected host e.g. ascaris
  • Ingestino of larvae in the tissue of an intermediate host e.g. taenia so.
37
Q

Inoculation

A
  • By a blood sucking insect e..g. filariasis

* By active penetrationof the larvae e.g. schistosomias, hookworls

38
Q

Schistosomiasis (bilharzia) Description

A

A trematode that infects man

39
Q

Schistosomiasis (bilharzia) 3 forms

A

S. haematobium – bladder (haematuria)
S, mansonii (blood vessels around gut eggs released in faeces
S. japonisum

40
Q

Schistosomiasis (bilharzia) Presentation

A
  • None- “swam in lake malawi”
  • “swimmer’s itch”
  • “katayama fever” – a seroconversion illness characterised by fever, arthralgia, uticarial rash, death
  • Haematuria
  • Portal hypertension e.g. haematemesis
  • Malignancy
  • Paraparesis
41
Q

Schistosomiasis (bilharzia)Diagnosis

A
  • Ova in urine, stool or biopsy
  • Immunodiagnosis
  • Eosinophila
42
Q

Schistosomiasis (bilharzia) Treatment

A

Praziquantel

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