Schmunis G A
Regional Office of the World Health Organization, Pan American Health Organization, Washington, DC 20037-2895, USA.
Mem Inst Oswaldo Cruz. 1999;94 Suppl 1:93-101. doi: 10.1590/s0074-02761999000700010.
Trypanosoma cruzi is a protozoan infection widely spread in Latin America, from Mexico in the north to Argentina and Chile in the south. The second most important way of acquiring the infection is by blood transfusion. Even if most countries of Latin America have law/decree/norms, that make mandatory the screening of blood donors for infectious diseases, including T. cruzi (El Salvador and Nicaragua do not have laws on the subject), there is usually no enforcement or it is very lax. Analysis of published serologic surveys of T. cruzi antibodies in blood donors done in 1993, indicating the number of donors and screening coverage for T. cruzi in ten countries of Central and South America indicated that the probability of receiving a potentially infected transfusion unit in each country varied from 1,096 per 10,000 transfusions in Bolivia, the highest, to 13.02 or 13.86 per 10,000 transfusions in Honduras and Venezuela respectively, where screening coverage was 100%. On the other hand the probability of transmitting a T. cruzi infected unit was 219/10,000 in Bolivia, 24/10,000 in Colombia, 17/10,000 in El Salvador, and around 2-12/10,000 for the seven other countries. Infectivity risks defined as the likelihood of being infected when receiving an infected transfusion unit were assumed to be 20% for T. cruzi. Based on this, estimates of the absolute number of infections induced by transfusion indicated that they were 832, 236, and 875 in Bolivia, Chile and Colombia respectively. In all the other countries varied from seven in Honduras to 85 in El Salvador. Since 1993, the situation has improved. At that time only Honduras and Venezuela screened 100% of donors, while seven countries, Argentina, Colombia, El Salvador, Honduras, Paraguay, Uruguay and Venezuela, did the same in 1996. In Central America, without information from Guatemala, the screening of donors for T. cruzi prevented the transfusion of 1,481 infected units and the potential infection of 300 individuals in 1996. In the same year, in seven countries of South America, the screening prevented the transfusion of 36,017 infected units and 7, 201 potential cases of transfusional infection.
克氏锥虫是一种原生动物感染，在拉丁美洲广泛传播，北起墨西哥，南至阿根廷和智利。通过输血感染该病是第二重要的途径。即使拉丁美洲的大多数国家都有法律/法令/规范，规定对献血者进行包括克氏锥虫在内的传染病筛查（萨尔瓦多和尼加拉瓜没有关于这方面的法律），但通常没有执法或执法非常宽松。对1993年发表的中南美洲十个国家献血者克氏锥虫抗体血清学调查的分析表明，每个国家接受潜在感染输血单位的概率各不相同，在玻利维亚每10000次输血中为1096例，概率最高，在洪都拉斯和委内瑞拉分别为每10000次输血13.02例或13.86例，这两个国家的筛查覆盖率为100%。另一方面，在玻利维亚，每10000次输血中传播克氏锥虫感染单位的概率为219例，在哥伦比亚为24例，在萨尔瓦多为17例，其他七个国家约为每10000次输血2 - 12例。克氏锥虫的感染风险定义为接受受感染输血单位时被感染的可能性，假定为20%。基于此，输血导致感染的绝对数量估计表明，在玻利维亚、智利和哥伦比亚分别为832例、236例和875例。在所有其他国家，数量从洪都拉斯的7例到萨尔瓦多的85例不等。自1993年以来，情况有所改善。当时只有洪都拉斯和委内瑞拉对100%的献血者进行了筛查，而在1996年，阿根廷、哥伦比亚、萨尔瓦多、洪都拉斯、巴拉圭、乌拉圭和委内瑞拉这七个国家也做到了这一点。在中美洲，由于没有危地马拉的信息，1996年对献血者进行克氏锥虫筛查避免了1481个感染单位的输血以及300人被潜在感染。同年，在南美洲的七个国家，筛查避免了36017个感染单位的输血以及7201例潜在的输血感染病例。
