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

Macrorhabdosis is a debilitating syndrome in budgerigars (Melopsittacus undulatus) due to the ascomycetous yeast Macrorhabdus ornithogaster. In the present study, occurrences of acute macrorhabdosis resulting in severe mortality in budgerigar fledglings and the effect of different treatment regimens for the control of the disease were investigated. The budgerigar (Melopsittacus undulates) flock consisted of over five hundred breeding adults. The morbidity of chicks reached 90% with more than 50% mortality. The significant clinical and pathological findings included distended abdomen, diarrhoea, ingluvitis, proventriculitis, and mild enteritis. Severe M. ornithogaster infection was diagnosed based on cytologic and histologic investigations. Three weeks of nystatin medication in the feed and vinegar administration in the drinking water led to moderate improvement of the flock mortality. After the initial treatment, 500 mg/Lsodium benzoate was administered in the drinking water for four weeks. The second treatment regimen was promisingly 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 samples became negative for the presence of M. ornithogaster. Based on these preliminary findings, sodium benzoate can be an efficient and inexpensive alternative to the previous labour intensive and expensive treatment using amphotericin B.