Successful treatment of macrorhabdosis in budgerigars (Melopsittacus undulatus) using sodium benzoate

Macrorhabdosis is a debilitating syndrome in budgerigars (Melopsittacus undulatus) due to theascomycetous yeast Macrorhabdus ornithogaster. In the present study, occurrences of acutemacrorhabdosis resulting in severe mortality in budgerigar fledglings and the effect of differenttreatment regimens for the control of the disease were investigated. The budgerigar (Melopsittacusundulates) flock consisted of over five hundred breeding adults. The morbidity of chicks reached90% with more than 50% mortality. The significant clinical and pathological findings includeddistended abdomen, diarrhoea, ingluvitis, proventriculitis, and mild enteritis. Severe M.ornithogaster infection was diagnosed based on cytologic and histologic investigations. Threeweeks of nystatin medication in the feed and vinegar administration in the drinking water led tomoderate improvement of the flock mortality. After the initial treatment, 500 mg/Lsodium benzoatewas administered in the drinking water for four weeks. The second treatment regimen waspromisingly effective in reducing mortality. However, some sick and retarded birds with M.ornithogaster with positive proventricular smears at necropsy were found in the flock.Consequently, a higher dosage of 1 gr/Lin drinking water for another four weeks was recommended.After the eight weeks of treatment, no new cases were found in the flock and all dropping samplesbecame negative for the presence of M. ornithogaster. Based on these preliminary findings, sodiumbenzoate can be an efficient and inexpensive alternative to the previous labour intensive andexpensive treatment using amphotericin B.