Difference between revisions of "Stephanofilaria stilesi"

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<big><center>[[Filarioidea|'''BACK TO FILARIOIDEA''']]</center></big>
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{{Taxobox
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|name              =''Stephanofilaira stilesi
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|kingdom            =
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|phylum            =
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|class              = [[Nematodes|Nematoda]]
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|sub-class          =
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|order              =
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|super-family      = [[Filarioidea]]
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|family            =
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|sub-family        =
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|genus              =
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==Stephanofilaira stilesi==
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==Hosts==
*Dermall lesions of cattle in USA
 
  
===Lifecycle===
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'''Intermediate hosts''':  The horn fly, ''[[Haematobia irritans]]''
*The infective larvae develop in the horn fly - Haematobia irritans
 
**Flies ingest microfilaria as they feed on cutaneous lesions. 
 
**Microfilaria develop into L3 larvae in the hornfly over 18-21 days. 
 
**Infective L3 larva are deposited into the skin when the fly bites again, where they grow into adult worms.
 
  
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'''Definitive hosts''':  Cattle
  
===Gross pathology===
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==Identification==
*Lesions begin as small circular patches on the ventral midline with serous exudate.
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These small [[Nematodes|nematodes]] are between 3-6mm in length. The eggs have thin shells, and are around 65μm in length. The microfilaria are 50μm long and enclosed in a spherical, vitelline membrane.
*These enlarge and coalesce producing lesions 25cm or more in diameter.
 
*Hemorrhage develops along the periphery while the older, central areas develop scabs or dry crusts. 
 
*Healing lesions are alopecic, lichenified plaques.
 
*Lesions may also occur on the flank, udder, teats, face and neck.
 
  
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==Lifecycle==
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Horn flies feed on lesions found on the host skin, and ingest microfilariae, as they feed on cutaneous lesions. They later develop into L3 in around 18-21 days.  The definitive host is infected when the fly leaves the L3 on the host.
  
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Causes [[Stephanofilariasis]].
  
===Histopathology===
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{{Learning
*Adult parasites occur within cystic diverticula of hair follicles or free within the adjacent dermis.
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|literature search = [http://www.cabdirect.org/search.html?q=title:(%22Stephanofilaria+stilesi%22) ''Stephanofilaria stilesi'' publications]
**Parasites may have lateral cords and lateral cuticular projections.
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}}
**The thick intestine is distinctive.  
 
**Microfilariae within uteri is the key feature. 
 
***Microfilariae also occur free within the dermis, in dermal lymphatics, or in the surface exudate. 
 
*There is little dermal reaction to adults in cystic hair follicles, but their presence within the dermis elicits eosinophilic and mononuclear inflammation.
 
  
===Differential diagnosis===
 
# Pelodera strongyloides: 
 
#*Rhabditid parasite, adults 1-1.5mm long, found in follicles
 
#*uteri contain eggs, not microfilaria.
 
# Dermatophytosis (Trichophyton verrucosum is most common)
 
# Mange (Chorioptes bovis)
 
# Fly bite dermatitis
 
# Contact dermatitis
 
# Zn-responsive dermatitis
 
# Other subcutaneous filarid parasites: 
 
#*Parafilaria bovicola (adult worms 30-70mm long, found coiled in nodules in subcutaneous and intramuscular connective tissues; not seen in US)
 
#*Onchocerca gutterosa (adult worms 60mm long, found in nuchal ligament and subcutaneous connective tissues).
 
  
==Stephanofilaria assamensis==
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{{OpenPages}}
*'Humpsore'
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*''Bos indicus'' in India
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[[Category:Filarioidea]]
*
 

Latest revision as of 18:35, 18 July 2012


Stephanofilaira stilesi
Class Nematoda
Super-family Filarioidea

Hosts

Intermediate hosts: The horn fly, Haematobia irritans

Definitive hosts: Cattle

Identification

These small nematodes are between 3-6mm in length. The eggs have thin shells, and are around 65μm in length. The microfilaria are 50μm long and enclosed in a spherical, vitelline membrane.

Lifecycle

Horn flies feed on lesions found on the host skin, and ingest microfilariae, as they feed on cutaneous lesions. They later develop into L3 in around 18-21 days. The definitive host is infected when the fly leaves the L3 on the host.

Causes Stephanofilariasis.


Stephanofilaria stilesi Learning Resources
CABICABI logo.jpg
Literature Search
Search for recent publications via CAB Abstract
(CABI log in required)
Stephanofilaria stilesi publications




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