[Infectiology] Protozoa

Taxonomy 

• Protozoa

Singular: protozoan . Plural: protozoans.

 

Classification  

Domain : Eukaryota  

Kingdom : Protozoa

• Phylum : Diplomonadida

• Phylum : Parabasalidea

• Phylum : Sarcomastigophora

[Infectiology] Basic taxonomy

Infectiology

Taxonomy is the science of defining and naming groups of biological organisms on the basis of shared characteristics.

This is a highly complex academic field, which considers enormous amounts of information. Taxonomic consensus changes continously, as more research is completed and more evidence is gathered.

 

Etymology

From Ancient Greek τάξις (táxis) = order, arrangement
From Ancient Greek νόμος (nómos) = law, custom

Taxonomy = the science of arrangement

 

Non-cellular 'life'

These are obligate infectious agents which cannot replicate independently of living organisms.

• Virus
• Prion 

 

The three domains

All living organisms can be categorised into three groups called domains: eukaryota, bacteria and archaea. This system was proposed in 1990.

• Eukaryota 

Eukaryotes are unicellular or multicellular organisms. The cells contain a nucleus enclosed within membranes.

• Prokaryota
• Bacteria
• Archaea 

Prokaryotes are unicellular or multicellular organisms. The cells which lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelle.

 

The seven kingdoms

All living organisms can be grouped into kingdoms.
This is a relatively simplistic taxonomic system, which is bothersome to taxonomists, but it is relatively accessible and popular. The 2015 system of 7 kingdoms, proposed by Ruggiero et al. follows below:

• Bacteria
• Archaea
• Protozoa
• Chromista
• Plantae
• Fungi
• Animalia

The kingdoms Chromista and Protozoa include organisms which have been called 'protists' (kingdom: Protoctista). Many sources still (inaccurately) refer to chromists as 'protozoa', 'fungi' or 'animals'. 

Sarcomastigophora

Sarcomastigophora is a phylum of protozoa.  

 

Classification  

Domain : Eukaryota  

Kingdom : Protozoa  

Phylum : Sarcomastigophora 

 

Class : Lobosa 

Order : Schizopyrenida  

Family : Entamoebidae

• Entamoeba gingivalis : Gum disease
• Entamoeba histolytica : Amoebiasis (amoebic dysentry), amoebic liver abscess, cutaneous amoebiasis, amoebic brain abscess

 

Class : Lobosa 

Order : Schizopyrenida 

Family : Vahlkampfiidae  

• Naegleria fowleri : Primary amoebic meningoencephalitis (very rare, about 300 reported cases)

 

Class : Zoomastigophorea  

Order : Kinetoplastida 

Family : Trypanosomatidae  

• Leishmania species : Leishmaniasis 
• Trypanosoma brucei species : African sleeping sickness (Trypanosomiasis)
• Trypanosoma cruzi species : Chagas disease (Trypanosomiasis) 

Eukaryota

Taxonomy 

• Eukaryota

Eukaryota is a domain of organisms.

 

Classification

Domain : Eukaryota

• Kingdom : Animalia

• Kingdom : Chromista

• Kingdom : Fungi

• Kingdom : Plantae

• Kingdom : Protozoa

Diplomonadida

Diplomonadida is a phylum of protozoa.  

 

Classification  

Domain : Eukaryota  

Kingdom : Protozoa  

Phylum : Diplomonadida 

Class : Diplomonadida

Order : Diplomonadida

Family : Hexamitidae

• Giardia lamblia : Giardiasis

 

Read more

• CDC profile on Giardiasis

Parabasalidea

Parabasalidea is a phylum of protozoa.  

 

Classification  

Domain : Eukaryota  

Kingdom : Protozoa  

Phylum : Parabasalidea 

 

Class : Trichomonada 

Order : Trichomonadida 

Family : Monocercomonadidae

• Dientamoeba fragilis : Dientamoebiasis 

 

Class : Trichomonada 

Order : Trichomonadida

Family : Trichomonadidae

• Trichomonas vaginalis : Trichomoniasis