ABSTRACT: I qualified as a veterinary nurse in 2009 on the degree course run by the Royal Veterinary College, Middlesex University and the College of Animal Welfare. The dissertation in my final year gave me the opportunity to review the subject of lungworm and this article deals with aspects of – and shortcomings in – the diagnosis and treatment of canine lungworm and how veterinary nurses could be instrumental in future developments.

A number of experiences with infected patients increased my interest in lungworm and one particular case awakened the need for further understanding. This case involved a healthy young Labrador retriever admitted for neutering and microchipping. Whilst under anaesthetic and when the microchip needle was being removed, the dog haemorrhaged profusely from the insertion site and surgery was not performed owing to patient risk. No coagulopathy problems had been detected and no other signs presented.

A month later, after being wormed and recording a negative Baermann’s test, the dog was castrated. This situation could have been fatal if neutering had been carried out first.

Background

The lungworm, Angiostrongylus vasorum, was first recorded by Baillet (1966) in France and has since increased its distribution globally (Figure 1). It was reported as imported to Britain by an infected greyhound from Ireland in 1975, having been noted in Ireland in 1968. Recently it has extended from existing endemic areas,2 and appears to be spreading northwards in Great Britain.

Figure 1: Angiostrongylus vasorum. (Image courtesy of E. R. Morgan)

This increase in population in the UK requires greater awareness and understanding.

Lungworm is a nematode transmitted to canids that ingest infected molluscs, such as slugs and snails. The cycle continues, infecting the environment and increasing the chance of spread (Figure 2).

Figure 2: Lungworm life cycle. (Image courtesy of Bayer Animal Healthcare)

Clinical signs are associated with cardio-respiratory damage and coagulation abnormalities (Table 1).

Signs result from larval migration around the body and the consequent effects on the body. Confusion of diagnosis often arises because of inconsistent signs, which emphasises the necessity for awareness of all possible presenting signs.

Diagnosis and treatment

Several diagnostic methods are suggested, including blood tests, radiography and faecal sampling. Boag et al., (2004) studied radiographs of infected dogs, highlighting that it is difficult, if not impossible, to diagnose lungworm relying solely on radiographic evidence, as there appeared to be no common pathological signs.

Traversa and Guglielmini (2008) remind us of the importance of using the ‘gold standard’ Baermann’s test, which when correctly applied, is a reliable diagnostic method.5 As veterinary nurses are the practice staff usually involved in carrying out such laboratory tests, it is vital they are confident and competent in the appropriate method.

A paper by Willesen et al., (2007) researched efficacy and safety when using imidacloprid/moxidectin and fenbendazole.2 Both were similar in success rates, being safe for the animals with minimal side effects. Importantly, it demonstrated how larvae decrease in numbers slowly and thus continue to shed into the environment, even after the dog has been suitably treated.

Knowledge of such therapeutic agents enables veterinary nurses, alongside veterinary surgeons, to be able to explain, advise and implement preventive routine treatments with full client co-operation and an understanding of the treatment required for infected patients.It should be noted, however, that fenbendazole is not currently licensed in the UK for the treatment of Angiostrongylus vasorum.

Literature review

A critical review of primary sources showed the strengths and limitations of available literature. A main media interest is the possibility that the geographic location of this lungworm is extending northwards and expanding from existing endemic foci. With new endemic areas arising, it is important that nurses are aware of conditions that may be present in different regions.

Morgan et al., (2008) studied Great Britain’s fox population showing a greater abundance of lungworm in the South East than was originally thought. It emphasises that here lungworm has a large population that could be transferred into the domestic dog population.

Taubert et al., (2009) studied faecal samples of dogs drawing attention to a seasonal pattern of infected patients. Although there were positive samples throughout the year, the number increased during winter and spring. This may result from the intermediate host’s survival depending on the climate; and is supported by Willis (2006) who studied the effect of the climate on slugs and Morgan et al., (2008) who suggest this increase may be caused by foxes’ dietary change in these seasons.

These seasonal changes could play a significant role in the implementation of preventive measures as, through discussion with the veterinary surgeon and client, the veterinary nurse can alter the treatment accordingly.

Much of the literature presents individual cases and, although they cannot be generalised, these show the various ways in which one condition can present itself. Such associated conditions include haemothorax, severe dyspnoea5, acute collapse, swelling and seizures.

Many articles stress possible severity of the condition with some patients presenting too late to treat10, even in 2008 dogs were still dying from this condition.

VN responsibilities and CPD requirements

With amendments to the Regulation of Veterinary Nurses coming into force in late 2010, it is vital that veterinary nurses are competent and aware of their actions.11

Adhering to continued professional development requirements and selfeducation through research ensures veterinary nurses are up-to-date with their knowledge and skills. This includes working with the veterinary surgeon’s support to give relevant advice to owners, implementing efficient practice protocols and using appropriate diagnostic testing methods, correctly.

Since the non-statutory register for veterinary nurses came into action in September 2007, CPD is required for all registered veterinary nurses at a minimum of 45 hours over three years. This ensures nurses are up to date, competent and capable in their actions and knowledge. It will facilitate refresher courses on testing technique to ensure accurate results. CPD on lungworm can be used to ensure veterinary nurses have adequate knowledge regarding its prevalence, control and spread (Table 2).

Keeping current with training provides the opportunity for nurses to pass on their knowledge and to fulfil their professional role as defined by the Royal College of Veterinary Surgeons.12 This can be reflected in practice.

Nurse clinics should be used to advantage to advise owners on lungworm and educate the community to reduce the spread of lungworm. Setting up practice protocols can prevent infection and disease, thereby complying with best practice. Updating their knowledge allows client education and protocols to be altered as research improves. Participation in research and further education fulfils the true role of the veterinary nurse regarding patients’ care and prevention of disease, as described in the Guide to Professional Conduct for Veterinary Nurses. 

There is great need for further research so that veterinary professionals become more successful in the diagnosis of lungworm infection, its treatment and the minimisation of its population spread.5&6 Further reliable research regarding how lungworms cause clinical signs and detail on the intermediate host’s involvement would provide veterinary professionals with knowledge that would be of benefit to their patients.

Research-based learning allows greater understanding and comprehension of Angiostrongylus vasorum, its pathological effects and related aspects. Veterinary surgeons should ensure all patients undergoing surgery are suitably wormed and tested prior to surgery to check that they are not infected with lungworm, thus reducing the chance of unexpected haemorrhage on the operating table. Possible prevention protocols and treatments should be considered for all patients.

Summary

This literature review has emphasised that valuable information on Angiostrongylus vasorum is available but not used to its full potential. The role of the veterinary nurse should be aimed at client education and participation in research to develop knowledge and improve nursing care by the use of protocols and advice.

This can be reflected in practice where seminars, together with leaflets and displays, can be used to educate clients. Professional practice must be maintained by wide reading and research as evidence is constantly changing.

Author

Harriet Oakley BSc(Hons) RVN

Harriet graduated from the Royal Veterinary College in London in 2009 after carrying out several placements in the Surrey area. Since then she has gone on to start the BVM&S degree at The Royal (Dick) School of Veterinary Studies in Edinburgh.

References

1.   JACOBS, D. and PROLE, J. (1975) Angiostrongylus vasorum and other nematodes in British greyhounds. Veterinary Record. 96: 180

2.   WILLESEN, J. L., KRISTENSEN, A. T., JENSEN, A. L., HEINE, J. and KOCH, J. (2007) Efficacy and safety of imidacloprid/moxidectin spot-on solution anc fenbendazole in the treatment of dogs naturally infected with Angiostrongylus vasorum (Baillet 1866). Veterinary Parasitology. 147: 258-264.

3.   MORGAN, E., SHAW, S., BRENNAN, S., DE WAAL, T., JONES, B. and MULCAHY, G. (2005) Angiostrongylus vasorum: a real heartbreaker. Trends in Parasitology. 21(2): 49-51.

4.   BOAG, A. K., LAMB, C. R., CHAPMAN, P. S. and BOSWOOD, A. (2004) Radiographic findings in 16 dogs infected with Angiostrongylus vasorum. The Veterinary Record. 1 54 (2): 426-430.

5.   TRAVERSA, D. and GUGLIELMINI, C. (2008) Feline aelurostrongylosis and canine angiostrongylosis: A challenging diagnosis for two emerging verminous pneumonia infections. Veterinary Parasitology. 1 57: 163-1 74.

6.   MORGAN, E. R., TOMLINSON, A., HUNTER, S., NICHOLS, T., ROBERTS, E., FOX, M. T. and TAYLOR, M. A. (2008). Angiostrongylus vasorum and Eucoleus aerophius in foxes [Vulpes vulpes] in Great Britain. Veterinary Parasitology. 154: 48-57.

7.   TAUBERT, A., PANTCHEV, N., VRHOVEC, M. G., BAUER, C. and HERMOSILLA, C. (2009) Lungworm infections (Angiostrongylus vasorum Crenosoma vulpis, Aelurostrongylus abstrusus] in dogs and cats in Germany and Denmark in 2003-2007. Veterinary Parasitology. 159: 175-180.

8.   WILLIS, J., BOHAN, D., CHOI, Y., CONRAD, K. and SEMENOV, M. (2006) Use of an individual-based model to forecast the effect of climate change of the dynamics, abundance and geographical range of the pest slug, Deroceras retculatum ir the UK. Global Change Biology. 12: 1643-1657.

9.   YAMAKAWA, Y., MCGARRY, J. W., DENK, D., DUKES-MCEWAN, J., MACDONALD, N., MAS, A., MCCONNELL, F., TATTON, B., VALENTINE, E. G., WAYNE, J., WILLIAMS, J. M. and HETZEL, U. (2009) E merging canine angiostrongylosis m northern England: in fatal cases. The Veterinary Record 164: 149-1 52.

10.   CHAPMAN, P. S., BOAG, E. K., GUITAIN, J. and BOSWOOD, A. (2004) Angiostrongylus vasorum infection in 23 dogs. Journal of Small Animal Practice. 45: 435-440.

11.   Royal College of Veterinary Surgeons (2008). Guide to Professional Conduct for Veterinary Nurses. London: RCVS, [Accessed 6th April 2009] VN Register [Online] Available from http://www.rcvs.org.uk/Templates/Internal.asp7N odeID=96375&int1stParentNodeID=89646

12.   Royal College of Veterinary Surgeons (September 2008) Veterinary Surgeons Act (1966) – as amended. Reed Elsevier (UK) Limited trading as LexisNexis UK. Available from: http://www.rcvs.org.uk/templates/internal.asp7nc deid=89679

Further reading

SASANELLI, M., PARADIES, P., OTRANTO, D., LIA, R. and DE CAPRARIIS, D. (2008) Haemothorax associated with Angicstrcngylus vasorum infection m a dog. Journal of Small Animal Practice. 49: 417-420. TRAVERSA, D., TORBIDONE, A., MALATESTA, D. and GUGLIELMINI, C. (2007) Occurrence of fatal canine Anglcstrcngylus vasorum infection in Italy. Veterinary Parasitology. 1 52: 162-166.

WILLESEN, J. L., BJORNVAD, C. R. and KOCH, J. (2008) Acute ha emoabdomen associated with Anglcstrcngylus vasorum infection in a dog: a case report. Irish Veterinary Journal. 61(2): 591-593.

 

• VOL 25 • No8 • August 2010 • Veterinary Nursing Journal