Avaliaçäo da influência do formol e do hipoclorito de sódio na pesquisa de oocistos de Cryptosporidium nas fezes, através do método de heine / The evaluation of the effect of formol and sodium hypochlorite on the demonstration of Cryptosporidium oocysts in feces by Heine's method

Cryptosporidium oocysts were searched by Heine's method in stools of nine calves with cryptosporidiosis after stool treatment with two disinfectants, 10 per cent paraformaldehyde solution and 14.5 per cent sodium hypochlorite solution. After 30 minutes exposition to sodium hypochlorite solution oocysts became non refractile and acquired a reddish tinge, making their identification difficult. No morphological alterations occurred in oocysts after paraformaldehyde treatment. We recommend paraformaldehyde at 10 per cent concentration as means of human immunodeficiency virus (HIV) inactivation for routine use in stool examinations and therefore making safer those type of procedures for laboratory personnel, when using Heine's method