Changes

Animals with right-sided congestive heart failure require stablisation with diuretics, ACE inhibitors and cage rest before treatment for heartworm disease is implemented. Animals with severe respiratory signs also require stabilisation with oxygen supplementation, anti-inflammatory doses of corticosteroid and anti-thrombotic drugs. The specific adulticidal treatment for ''Dirofilaria immitis'' is melarsomine dihydrochoride, a new generation arsenical compound. Melarsomine is administered

Animals with right-sided congestive heart failure require stablisation with diuretics, ACE inhibitors and cage rest before treatment for heartworm disease is implemented. Animals with severe respiratory signs also require stabilisation with oxygen supplementation, anti-inflammatory doses of corticosteroid and anti-thrombotic drugs. The specific adulticidal treatment for ''Dirofilaria immitis'' is melarsomine dihydrochoride, a new generation arsenical compound. Melarsomine is administered

intramuscularly into the epaxial, and pressure should be applied during and after needle withdrawal³. A "graded-kill" protocol is recommended: an initial injection is followed one month later with two injections at an interval of 24 hours, given on opposite sides^1-4. This spreads the killing effects over two treatments, with an aim to reducing the occurence of thromboembolism after parasite death. Cage rest and anti-inflammatory doses of corticosteroids in the week following melarsomine treatment can also reduce the likelihood of pulmonary thromboembolism. Adulticidal treatment may be declined by the owner, owing to the risk of thromboembolism. Alternatively, it may not be possible to implement adulticidal treatment if the patient is suffering renal or hepatic failure³. In these cases, monthly administration of prophylactic doses of ivermectin

intramuscularly into the epaxial, and pressure should be applied during and after needle withdrawal³. A "graded-kill" protocol is recommended: an initial injection is followed one month later with two injections at an interval of 24 hours, given on opposite sides^1-4. This spreads the killing effects over two treatments, with an aim to reducing the occurence of thromboembolism after parasite death. Cage rest and anti-inflammatory doses of corticosteroids in the week following melarsomine treatment can also reduce the likelihood of pulmonary thromboembolism. Antigen testing four months after adulticidal treatment will determine whether it is necessary to repeat the therapy³.

is a reasonable treatment option, as it prevents further infection and may kill some adult nematodes².

 

Adulticidal treatment may be declined by the owner, owing to the risk of thromboembolism. Alternatively, it may not be possible to implement adulticidal treatment if the patient is suffering renal or hepatic failure³. In these cases, monthly administration of prophylactic doses of ivermectin is a reasonable treatment option, as it prevents further infection and may kill some adult nematodes².

Even low grade infections in cats may result in pulmonary thromboembolism with adulticidal treatment. Because of this, symptomatic treatment of sick cats may be followed by surgical or catheter-based extraction of nematodes once the patient is stable³. Stablisation is similar to that for feline asthma, and can include cage rest, oxygen supplementation, bronchodilators (e.g. theophylline), tapering doses of prednisolone, and balanced fluid therapy if indicated³. Heartwoms have a much shorter life-span in cats, and spontaneous remission is seen in some cases. Regular monitoring may therefore be the best course of action in clinically well cats.

Even low grade infections in cats may result in pulmonary thromboembolism with adulticidal treatment. Because of this, symptomatic treatment of sick cats may be followed by surgical or catheter-based extraction of nematodes once the patient is stable³. Stablisation is similar to that for feline asthma, and can include cage rest, oxygen supplementation, bronchodilators (e.g. theophylline), tapering doses of prednisolone, and balanced fluid therapy if indicated³. Heartwoms have a much shorter life-span in cats, and spontaneous remission is seen in some cases. Regular monitoring may therefore be the best course of action in clinically well cats.

No drugs are specifically approved for microfilaricidal treatment of ''Dirofilaria immitis'', and successful elimination of adult worms should results in the demise of circulating microfilariae four to six weeks later². Single doses of ivermectin, milbemycin oxime, moxidection or selamectin are, however, effective at removing microfilariae from the circulation. The sudden death of large numbers of microfilariae may invoke an anaphylactic response, and oral prednisolone may be administered with microfilaricides to help prevent this.

No drugs are specifically approved for microfilaricidal treatment of ''Dirofilaria immitis'', and successful elimination of adult worms should results in the demise of circulating microfilariae four to six weeks later². Single doses of ivermectin, milbemycin oxime, moxidection or selamectin are, however, effective at removing microfilariae from the circulation. The sudden death of large numbers of microfilariae may invoke an anaphylactic response, and oral prednisolone may be administered with microfilaricides to help prevent this.

   

   

 

Heartworm prophylaxis should be implemented in all cats and dogs living in or visiting areas in which ''Dirofilaria immitis'' is endemic. Ivermectin or milbemycin oxime can be given ''per os'' on a monthly basis, and selemectin spot-on is effective when applied each month. If animals have already been exposed to ''Dirofilaria immitis' it may be wise to perform an antigen test before starting treatment. In endemic countries, routine antigen testing six months after the end of the previous heartworm season will detect infections that have slipped through the net, and enable treatment during the mild, early stages of disease³.

Heartworm prophylaxis should be implemented in all cats and dogs living in or visiting areas in which ''Dirofilaria immitis'' is endemic. In the UK, milbemycin oxime and selamectin are licensed for the prevention of heartworm disease and should be administered on a monthly basis as they are capable of killing migrating larvae up to week six post-infection. In the event of non-compliance or a missed dose, it may be necessary to test the animal for ''Dirofilaria immitis'' six months later if they are likely to have been exposed to infection during the time they were unprotected. Drugs that persist in the long term, such as injectable moxidectin, can help overcome this issue.

==Prognosis==

==Prognosis==