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Oestrus ovis (view source)

Revision as of 13:43, 26 July 2010

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The adult fly is 13-15mm in length and grey in colour, with black spots along the abdomen.

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Mature larvae are around 30mm and are yellow in colour. They have distinct black bands along the dorsal body ~~segement~~.

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Mature larvae are around 30mm and are yellow in colour. They have distinct black bands along the dorsal body segment.

==Life cycle==

The female is viviparous and infects the host by squirting larvae into the nostrils of sheep in a jet of liquid.

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The larvae crawl caudally into the nasal cavity and feed on the nasal mucosa and mature, before returning to the nostrils. The ~~larve~~ move to the frontal sinuses, where they transform from L2 to L3. They only move to the frontal sinuses under warm conditions. If these conditions are not achieved, the larvae will stay in the nostrils for an extended period of time, until the warm conditions come about.

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The larvae crawl caudally into the nasal cavity and feed on the nasal mucosa and mature, before returning to the nostrils. The larvae move to the frontal sinuses, where they transform from L2 to L3. They only move to the frontal sinuses under warm conditions. If these conditions are not achieved, the larvae will stay in the nostrils for an extended period of time, until the warm conditions come about.

The larvae are then sneezed out into the ground, and pupate on the ground. The adults develop, and are active throughout the year. Adult flies only live for 2-3 weeks

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~~'''Pathogenesis'''~~

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*Adult flies cause annoyance

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**Interrupts feeding

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**Leads to a decreased weight gain

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*Larvae cause nasal irritation, nasal discharge and sneezing

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**Irritate the nasal mucosa with oral hooks and spines causing a viscous exudate to be produced from which they feed

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**Heavy infestations lead to erosion of the bones in the sinuses (turbinate bones)

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**Penetration of the brain leads to '''false gid''' (high stepping gait and incoordination)

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*[[Respiratory Parasitic Infections - Pathology#Oestrus ovis|Pathology in the nasal cavity]]

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~~'''Control'''~~

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*Systemic [[Ectoparasiticides|insecticides]] can be used in heavy infestations

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*In warmer countries, strategic prophylactic treatment can be used

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*Larvae in the [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|nasal cavity]] of sheep and goats = Nasal bots

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*Causes reaction in [[Paranasal Sinuses Inflammatory - Pathology#Sinusitis|sinuses]]

[[Media:Oestrus ovis.mp4]]

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[[Category:Oestridae]]

[[Category:To_Do_-_Max]]

[[Category:Respiratory Parasitic Infections]][[Category:Sheep]]

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