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Also known as: '''''French Heartworm  

<p>Do not confuse with: Heartworm caused by ''[[Dirofilaria immitis]]''</p>

| Also known as:

==Introduction==

| French Heartworm<br>

| Do not confuse with:

| [[Heartworm - Dog|'''Heartworm''']] caused by ''[[Dirofilaria immitis]]''

 

==Description==

Angiostrongylosis is a clinical syndrome of dogs caused by infection with ''[[Angiostrongylus vasorum]]'', the 'French heartworm' or 'lungworm'.  The adult worms accumulate in the pulmonary arterial vessels and right heart chambers and release eggs and larvae into the pulmonary circulation.  The adult worms obstruct blood flow through the pulmonary vasculature and lead to the development of pulmonary undercirculation, right ventricular hypertrophy and [[Cor Pulmonale|cor pulmonale]].  The adults also cause local pulmonary arteritis and [[Thrombosis|thrombi]] are able to form against the inflamed vessel wall.   

Angiostrongylosis is a clinical syndrome of dogs caused by infection with ''[[Angiostrongylus vasorum]]'', the 'French heartworm' or 'lungworm'.  The adult worms accumulate in the pulmonary arterial vessels and right heart chambers and release eggs and larvae into the pulmonary circulation.  The adult worms obstruct blood flow through the pulmonary vasculature and lead to the development of pulmonary undercirculation, right ventricular hypertrophy and [[Cor Pulmonale|cor pulmonale]].  The adults also cause local pulmonary arteritis and [[Thrombosis|thrombi]] are able to form against the inflamed vessel wall.   

The eggs lodge in the small pulmonary capillaries and the L1 larvae hatch at this location.  These larvae penetrate the capillaries and enter the pulmonary parenchyma to cause an interstitial [[Pneumonia|pneumonia]].  This pneumonia is the major cause of the respiratory signs observed in infested animals but, in severely affected animals, [[Lungs Circulatory - Pathology#Pulmonary oedema|pulmonary oedema]] may also develop.  By an unknown mechanism, the presence of infection reduces the blood concentrations of factors V and VIII and causes thrombocytopathia and thrombocytopaenia.  Affected animals therefore often suffer from some form of coagulopathy.

The eggs lodge in the small pulmonary capillaries and the L1 larvae hatch at this location.  These larvae penetrate the capillaries and enter the pulmonary parenchyma to cause an [[Interstitial Pneumonia|interstitial pneumonia]].  This pneumonia is the major cause of the respiratory signs observed in infested animals but, in severely affected animals, [[Pulmonary Oedema|pulmonary oedema]] may also develop.  By an unknown mechanism, the presence of infection reduces the blood concentrations of [[Normal_Mechanisms_of_Haemostatic_Control#Coagulation_physiology|factors V and VIII]] and causes [[Thrombocytopaenia#Thrombocytopathia|thrombocytopathia]] and [[Thrombocytopaenia#Thrombocytopaenia|thrombocytopaenia]].  Affected animals therefore often suffer from some form of coagulopathy.

==Signalment==

==Signalment==

The lungworm is acquired when dogs eat slugs and snails infected the the L3 larvae. It is therefore crucial to establish whether the dog does eat slugs or snails.  As foxes are also able to act as definitive hosts, areas with a dense population of '''foxes''' are likely to have a high lungworm prevalence.  ''A. vasorum'' was traditionally considered to be a disease acquired by animals that had travelled to Europe but it is now being diagnosed in untravelled animals as far north in the UK as Scotland<ref>Helm J, Gilleard JS, Jackson M, Redman E, Bell R. '''A case of canine Angiostrongylus vasorum in Scotland confirmed by PCR and sequence analysis.''' ''J Small Anim Pract. 2009 May;50(5):255-9.''</ref>.

The lungworm is acquired when dogs eat slugs and snails infected with the L3 larvae. It is therefore crucial to establish whether the dog does eat slugs or snails.  As foxes are also able to act as definitive hosts, areas with a dense population of '''foxes''' are likely to have a high lungworm prevalence.  ''A. vasorum'' was traditionally considered to be a disease acquired by animals that had travelled to Europe but it is now being diagnosed in untravelled animals as far north in the UK as Scotland<ref>Helm J, Gilleard JS, Jackson M, Redman E, Bell R. '''A case of canine Angiostrongylus vasorum in Scotland confirmed by PCR and sequence analysis.''' ''J Small Anim Pract. 2009 May;50(5):255-9.''</ref>.

==Diagnosis==

==Diagnosis==

===Clinical Signs===

===Clinical Signs===

Clinical signs are mainly related to coagulopathies and the presence of worms, eggs and larvae in the pulmonary vasculature and parenchyma.  They include:

Clinical signs are mainly related to coagulopathies and the presence of worms, eggs and larvae in the pulmonary vasculature and parenchyma.  They include:

The results of a recent study indicate that the most common clinical signs observed in infected dogs are '''cough''' (65%), '''dyspnoea''' (43%), '''coagulopathy''' (35%) and '''collapse''' (26%)<ref>Chapman PS, Boag AK, Guitian J, Boswood A. '''Angiostrongylus vasorum infection in 23 dogs (1999-2002).''' ''J Small Anim Pract. 2004 Sep;45(9):435-40.''</ref>.  

 

 

 

 

The results of a recent study indicate that the most common clinical signs observed in infected dogs are '''cough''' (65%), '''dyspnoea''' (43%), '''coagulopathy''' (35%) and '''collapse''' (26%)<ref>Chapman PS, Boag AK, Guitian J, Boswood A. '''Angiostrongylus vasorum infection in 23 dogs (1999-2002).''' ''J Small Anim Pract. 2004 Sep;45(9):435-40.''</ref>.

 

===Laboratory Tests===

===Laboratory Tests===

Blood '''eosinophilia''' and '''basophilia''' may or may not be present.  In one study, eosinophilia was detected in 21% of naturally infected dogs<ref name="one">Willesen JL, Jensen AL, Kristensen AT, Koch J. '''Haematological and biochemical changes in dogs naturally infected with Angiostrongylus vasorum before and after treatment.''' ''Vet J. 2009 Apr;180(1):106-11. Epub 2007 Dec 20.''</ref>  Animals may or may not be '''thrombocytopaenic''' and '''[[Anaemia|anaemic]]''' and a case of concurrent immune-mediated thrombocytopaenia with ''A. vasorum'' infection has been reported<ref>Gould SM, McInnes EL. '''Immune-mediated thrombocytopenia associated with Angiostrongylus vasorum infection in a dog.''' ''J Small Anim Pract. 1999 May;40(5):227-32.''</ref>.  

Blood '''eosinophilia''' and '''basophilia''' may or may not be present.  In one study, eosinophilia was detected in 21% of naturally infected dogs<ref name="one">Willesen JL, Jensen AL, Kristensen AT, Koch J. '''Haematological and biochemical changes in dogs naturally infected with Angiostrongylus vasorum before and after treatment.''' ''Vet J. 2009 Apr;180(1):106-11. Epub 2007 Dec 20.''</ref>  Animals may or may not be '''thrombocytopaenic''' and '''anaemic''' and a case of concurrent immune-mediated thrombocytopaenia with ''A. vasorum'' infection has been reported<ref>Gould SM, McInnes EL. '''Immune-mediated thrombocytopenia associated with Angiostrongylus vasorum infection in a dog.''' ''J Small Anim Pract. 1999 May;40(5):227-32.''</ref>.  

'''Fructosamine''' concentration may be low in cases of ''A. vasorum'' infection and this finding may prompt examination of a faecal sample<ref name="one">nothing</ref><ref>Willesen JL, Jensen AL, Kristensen AT, Kjelgaard-Hansen M, Jessen R, Koch J. '''Serum fructosamine concentrations in 59 dogs naturally Infected with Angiostrongylus vasorum.''' ''J Vet Med A Physiol Pathol Clin Med. 2006 Jun;53(5):266-9.''</ref>.

'''Fructosamine''' concentration may be low in cases of ''A. vasorum'' infection and this finding may prompt examination of a faecal sample<ref name="one">nothing</ref><ref>Willesen JL, Jensen AL, Kristensen AT, Kjelgaard-Hansen M, Jessen R, Koch J. '''Serum fructosamine concentrations in 59 dogs naturally Infected with Angiostrongylus vasorum.''' ''J Vet Med A Physiol Pathol Clin Med. 2006 Jun;53(5):266-9.''</ref>.

'''Coagulation times''' may be prolonged due to the consumptive coagulopathy.

[[Coagulation Tests|'''Coagulation times''']] may be prolonged due to the consumptive coagulopathy.

 

===Diagnostic Imaging===

===Diagnostic Imaging===

'''Plain radiographs of the chest''' may show enlargement of the right heart chambers and truncation of pulmonary arterial vessels.  There may be an alveolar lung pattern due to pulmonary haemorrhage or pneumonia.

'''Plain radiographs of the chest''' may show enlargement of the right heart chambers and truncation of pulmonary arterial vessels.  There may be an alveolar lung pattern due to pulmonary haemorrhage or pneumonia.

===Other Tests===

===Other Tests===

The gold standard test is considered to be identification of L1 larvae in faeces.  At least five faecal samples should be submitted for examination by the Baermann technique as excretion of the larvae is variable<ref>McGarry JW, Morgan ER. '''Identification of first-stage larvae of metastrongyles from dogs.''' ''Vet Rec. 2009 Aug 29;165(9):258-61.''</ref><ref>Humm K, Adamantos S. '''Is evaluation of a faecal smear a useful technique in the diagnosis of canine pulmonary angiostrongylosis?''' ''J Small Anim Pract. 2010 Apr;51(4):200-3. Epub 2010 Mar 1.''</ref>.

The '''gold standard test is considered to be identification of L1 larvae in faeces'''.  At least five faecal samples should be submitted for examination by the Baermann technique as excretion of the larvae is variable<ref>McGarry JW, Morgan ER. '''Identification of first-stage larvae of metastrongyles from dogs.''' ''Vet Rec. 2009 Aug 29;165(9):258-61.''</ref><ref>Humm K, Adamantos S. '''Is evaluation of a faecal smear a useful technique in the diagnosis of canine pulmonary angiostrongylosis?''' ''J Small Anim Pract. 2010 Apr;51(4):200-3. Epub 2010 Mar 1.''</ref>.

===Pathology===

===Pathology===

Infection with ''Angiostrongylus vasorum'' may be treated easily with suitable anthelmintics.  Ideally, four 5 day courses of a [[Benzimidazoles|benzimidazole]] should be administered at a high dose rate over 1-2 months.  '''Fenbendazole''' is widely available in the UK in a granule form and this is used most frequently in the treatment of ''A. vasorum''.  If infection is suspected but larvae cannot be detected in faeces, it may still be worth treating the animal.

Infection with ''Angiostrongylus vasorum'' may be treated easily with suitable anthelmintics.  Ideally, four 5 day courses of a [[Benzimidazoles|benzimidazole]] should be administered at a high dose rate over 1-2 months.  '''Fenbendazole''' is widely available in the UK in a granule form and this is used most frequently in the treatment of ''A. vasorum''.  If infection is suspected but larvae cannot be detected in faeces, it may still be worth treating the animal.

Alternatively, an '''imidacloprid/moxidectin''' spot-on can be used as a single application but this was found to have a lower efficacy than fenbendazole in the clearance of infection<ref>Willesen JL, Kristensen AT, Jensen AL, Heine J, Koch J '''Efficacy and safety of imidacloprid/moxidectin spot-on solution and fenbendazole in the treatment of dogs naturally infected with Angiostrongylus vasorum (Baillet, 1866).''' ''Vet Parasitol. 2007 Jul 20;147(3-4):258-64. Epub 2007 Jun 4.''</ref>.

Alternatively, an '''[[Ectoparasiticides|imidacloprid]]'''/'''[[Macrocyclic Lactones|moxidectin]]''' spot-on can be used as a single application but this was found to have a lower efficacy than fenbendazole in the clearance of infection<ref>Willesen JL, Kristensen AT, Jensen AL, Heine J, Koch J '''Efficacy and safety of imidacloprid/moxidectin spot-on solution and fenbendazole in the treatment of dogs naturally infected with Angiostrongylus vasorum (Baillet, 1866).''' ''Vet Parasitol. 2007 Jul 20;147(3-4):258-64. Epub 2007 Jun 4.''</ref>.

==Prevention==

==Prevention==

==Prognosis==

==Prognosis==

Animals affected by clinical disease may become severely ill but, if the infection is cleared, they usually suffer few sequelae.

Animals affected by clinical disease may become severely ill but, if the infection is cleared, they usually suffer few adverse consequences.

 

==References==

==References==

<references/>

<references/>

[[Category:Dog]][[Category:To_Do_-_James]][[Category:Cardiovascular_System_-_Vascular_Pathology]][[Category:Arterial_Pathology]][[Category:Respiratory_System_-_Inflammatory_Pathology]]

 

 

[[Category:Cardiovascular Diseases - Dog]][[Category:Lymphoreticular and Haematopoietic Diseases - Dog]][[Category:Cardiovascular_System_-_Vascular_Pathology]][[Category:Arterial_Pathology]]

[[Category:Expert_Review]]

[[Category:Cardiology Section]]