Pulmonary Parasites Flashcards
Provide an overview of the taxonomy off Dictyocaulidae
Phylum:
Nemathelminths
Class:
Nematoda
Sub-Class:
Secernentea
Order:
Strongyloides
Super Family:
Trichostrongyloidea
Outline the three types of Dictyocaulus species
D. Viviparus
D. Filaria
D Arnfeldi
Outline the life cycle of D. Viviparus
Eggs laid by females hatch in the airways and first stage larvae (L1) pass in the faeces
Develope into third stage larvae (L3) whilst in the environment
Infection occurs when cattle consume L3
Larvae migrate in the vasculature to the lungs, leave the branches of the pulmonary artery and migrate through the lung parenchyma to the airways, where they remain as adults
Outline the pathology of D. Viviparus
Usually seen in cattle on permanent pastures used for seasonal grazing in the UK and Europe, but widespread throughout world
Cattle exposed to D. viviparus develop rapid immunity
Hypobiosis (dormancy) of larval stage has been demonstrated in adult cattle
L3 larvae may overwinter on pasture in enough numbers to cause disease the following spring but conditions need to be favourable
List the clinical signs of D. Viviparus
Coughing
Respiratory rate
Lung auscultation
Other signs such as Respiratory distress (dyspnoea), gasping for air with head and neck outstretched. Salivation, loss of appetite, fever in severe infection
Outline the diagnosis process for D. Viviparus
Baermann apparatus is used to detect L1 larvae in faeces
ELISA test (antibodies)
Post mortem -adults in lungs
Outline what treatments are available for D. Viviparus
Anthelmintic treatment
Albendazole
Doramectin
Ivermectin
Moxidectin
Levamisole
Huskvac Vaccine
- Irradiated L3 larvae (2 oral doses given to calves in winter before turn out)
- Protective response against L4 (therefore response protects against the
development of adults which produce eggs)
What is Husk?
Parasites which live in the trachea and bronchi
Outline the life cycle of D. Arnfeldi
Larvated eggs, and very rarely first-stage larvae, pass in the feces.
In the environment, the eggs hatch and the larvae released undergo two moults to the infective third stage.
Infection of the donkey is by ingestion of the infective larvae.
Larval migration in donkeys follows the same route a D. viviparus in cattle.
The pre-patent period of D. arnfieldi in donkeys is approximately 12 to 14 weeks. In horses, the infection very rarely becomes patent.
List the clinical signs of D. Arnfieldi
In donkeys, D. arnfieldi is sometimes associated with clinical signs, although heavy infections may lead to coughing and respiratory distress. In horses, the pre-adult larvae, particularly if present in large numbers, can result in a range of respiratory symptoms, including coughing.
Outline the diagnostic process for D. Arnifieldi
Bronchoalveolar/tracheal wash may reveal worms and large number of eosinophils
Outline the treatments available for D. Arnfieldi
Ivermectin (eqvalan)
Fenbendazole (panacur)
Moxidectin has also been used
Outline the taxonomy of lungworm in companion animals
Phylum:
Nemathelminths
Class:
Nematoda
Sub-Class:
Secernentea
Order:
Strongyloides
Super Family:
Metastrongyloidea
List the common types of lungworm species and which animals they infect
Angiostrongylus vasorum - Dog
Aelurostrongylus abstrusus - Cat
Muellerius Capillaries
Protostrongylus
- Sheep and Goats
Metastrongylus - Swine
Outline the life cycle of Angiostrongylus vasorum
Undergoes an indirect life cycle with gastropod (terrestrial snails/slugs) intermediate hosts.
Adult parasites live in the right ventricle and pulmonary arteries of the definitive host (canid).
They produce eggs which develop into first stage larvae which are coughed up, swallowed, and passed in faeces of the canid definitive host.
First-stage larvae from faeces enter gastropod intermediate hosts where they develop to infective third-stage larvae (L3).
Canid definitive hosts become infected when they consume a gastropod containing infective L3, or L3 that have emerged spontaneously from the gastropods.
Frogs and birds may serve as paratenic hosts, but their role in transmission is not clear.
The pre-patent period from ingestion of an L3 to production of L1 in faeces is 6-8 weeks.