Pasteurization of human milk to prevent transmission of Chagas disease

Abstract

SUMMARYAlthough admittedly transmission of Trypanosoma cruzi infection through breastfeeding is a rare event, it involves serious risks. To test the effectiveness of pasteurization in preventing this mode of infection, three sets of samples of human milk were tested: acontaminated with T. cruzi and pasteurized; b -contaminated with T. cruzi and non-pasteurized; c -non-contaminated and pasteurized. Samples from all sets were orally and intraperitoneally administered to 90 BALB/c mice. The animals inoculated with contaminated, non-pasteurized samples, got the infection. Controls and the animals inoculated with contaminated and pasteurized milk were not infected. The hypothesis was accepted that pasteurization inactivates T. cruzi trypomastigotes. KEYWORDS:Trypanosoma cruzi; Pasteurization of human milk; Milk banks.Control of populations of Trypanosoma cruzi vectors, to a large extent achieved in Brazil, was followed by a marked reduction in the frequency of new cases of Chagas disease. Alternative modes of transmission, breastfeeding among them, were thus put to the foreground. MAZZA et al 6 . reported in 1936 the first finding of T. cruzi in human milk, namely from a patient in the acute phase of Chagas disease. DISKO & KRAMPITZ 5 (1971) observed numerous T. cruzi trypomastigotes in the milk of experimentally infected mice and pointed out that this was not due to contamination of milk with blood from ruptured vessels. However, they were unable to demonstrate the infection of suckling mice via contaminated milk. Likewise, CAMPOS et al. 4 found that experimentally infected female mice failed to infect their litters through suckling. MILES 9 (1972) detected T. cruzi trypomastigotes and anti-T. cruzi antibodies in the milk of mice in the acute phase of the infection. MEDINA-LOPES 7,8 reported in 1983 and 1988, respectively, two cases of infants, born of infected mothers, who developed acute Chagas disease while being breastfed, which was attributed to the ingestion of blood from papillary fissures. BITTENCOURT et al. 3 (1988) and AMATO NETO et al. 2 (1992) could not demonstrate the presence of T. cruzi in the milk of infected mothers. AMATO NETO et al. 1 (1999) evaluated experimentally the penetration, through the digestive tract, of T. cruzi trypomastigotes suspended in liquid foods. Although admittedly it is a rare event, human to human transmission of T. cruzi through breastfeeding must be prevented whenever possible. Accordingly, infected women reaching fertile age should be regarded as a potential health hazard to their offspring. One should not underestimate the risk of transmission from infected nursing mothers who, possibly unaware of their condition, are also milk bank donors. This risk obviously increases when the mothers involved are in the acute phase of the infection. Pasteurization inactivates the causative agents of many diseases (including HIV)10 , in which case it will not be necessary to deprive infants of their mother's milk. To evaluate the effectiveness of pasteurization in inactivating...

Chronic Chagas disease: from basics to laboratory medicine

“…Trypanosoma cruzi transmission by infected mother ' s milk or by milk contaminated with blood from papillary fissures has been described as cited in [21] but these appear to be rare events. The potential risk of T. cruzi transmission by transplantation of infected organs should be not neglected [22] .…”

Recomendações quanto à amamentação na vigência de infecção materna

“…Rats orally and intraperitoneally inoculated with human milk containing the parasite were infected; however, the control group with animals inoculated with pasteurized milk was not infected. 43,44 Animal experiments using human milk heated to 63 o C in a household microwave oven (7 minutes, 45% power) proved efficient in reducing the transmission of Trypanossoma cruzi. 45 …”

Recommendations for breastfeeding during maternal infections

“…Ratos inoculados por via oral e intraperitonial com leite humano contendo o parasita foram contaminados, porém o grupo controle com animais inoculados com leite pasteurizado não foi infectado 43,44 . Estudos realizados com animais de laboratório utilizando-se leite humano aquecido à temperatura de 63 o C em forno de microondas doméstico (7 minutos, 45% potência) mostrou ser eficaz na redução da transmissão do Trypanosoma cruzi 45 .…”