Frenkel J K, Hassanein K M, Hassanein R S, Brown E, Thulliez P, Quintero-Nunez R
Department of Pathology and Oncology, University of Kansas Medical Center, Kansas City, USA.
Am J Trop Med Hyg. 1995 Nov;53(5):458-68. doi: 10.4269/ajtmh.1995.53.458.
A cohort of more than 500 children from Panama City, Panama was studied prospectively over five years for acquisition of antibody to Toxoplasma gondii. The direct agglutination test showed that 72 of 571 children seroconverted between one and six years of age, for a cumulative incidence of 12.6%. Children were examined by pediatricians quarterly, and illnesses that had occurred in the interval and their activities were noted on questionnaires. Thirty-eight variables were examined for their role as risk factors for seroconversion. There was a higher correlation between children's seroconversion and contact with dogs than with cats. Combinations of significant predictors without dogs explained only 67% of the seroconversions, but the same factors with dogs explained 90%. On the other hand, ingestion of raw or rare meat or eggs appeared to play no role in transmission. Cats were examined and 110 (45.6%) of 241 had Toxoplasma antibody on the first bleeding. Only two (0.5%) of 383 cat fecal specimens, when tested in mice, resulted in seroconversion. Ten (1.1%) of 924 soil samples resulted in seroconversion in mice that had been injected. Antibody to Toxoplasma was found in 52 (23.3%) of 226 rats (Rattus norvegicus) and two (0.035%) of 571 mice (Mus musculus). Two hundred sixteen birds of 16 different species were bled. Antibody to Toxoplasma was found in 13.4% of these birds, mostly in grackles, blue-gray tanagers, and doves. The rate of isolation of Toxoplasma was low: one of 23 in rats and three of 201 in birds. High relative risks (RRs) of transmission to children were predicted by contact histories with nursing dogs (RR = 5.8), weaned dogs (RR = 4.7), many flies (RR = 3.6), 6-12-month-old dogs (RR = 3.4), weaned cats (RR = 3.0), 6-12-month-old cats (RR = 2.7), nursing cats (RR = 2.5), much garbage (RR = 2.4), and many roaches (RR = 2.2). The high statistical correlation of dog contact with seroconversion in children suggests the possibility that dogs, by eating and rolling in cat feces, are instrumental in mechanically transmitting Toxoplasma infection. In addition, flies, and to a lesser extent, cockroaches, may have practically important roles in transmission.
对来自巴拿马巴拿马城的500多名儿童进行了一项前瞻性研究，为期五年，以观察弓形虫抗体的获得情况。直接凝集试验显示，571名儿童中有72名在1至6岁之间血清学转换，累积发病率为12.6%。儿科医生每季度对儿童进行检查，并通过问卷记录在此期间发生的疾病及其活动情况。对38个变量作为血清学转换危险因素的作用进行了研究。儿童血清学转换与接触狗之间的相关性高于与猫的接触。没有狗的情况下，显著预测因素的组合只能解释67%的血清学转换情况，但有狗时相同因素能解释90%。另一方面，摄入生肉或未煮熟的肉或鸡蛋似乎在传播中不起作用。对猫进行了检查，241只猫中有110只（45.6%）在首次采血时有弓形虫抗体。在383份猫粪便标本中，只有两份（0.5%）在小鼠试验中导致血清学转换。924份土壤样本中有10份（1.1%）在注射小鼠后导致血清学转换。在226只褐家鼠中有52只（23.3%）检测到弓形虫抗体，在571只小家鼠中有两只（0.035%）检测到。对16种不同鸟类的216只进行了采血。在这些鸟类中有13.4%检测到弓形虫抗体，主要是鹩哥、蓝灰唐纳雀和鸽子。弓形虫的分离率很低：大鼠中23只里有1只，鸟类中201只里有3只。与哺乳犬接触（相对危险度RR = 5.8）、断奶犬（RR = 4.7）、大量苍蝇（RR = 3.6）、6至12月龄犬（RR = 3.4）、断奶猫（RR = 3.0）、6至12月龄猫（RR = 2.7）、哺乳猫（RR = 2.5）、大量垃圾（RR = 2.4）和大量蟑螂（RR = 2.2），预测了儿童感染弓形虫的高相对危险度。儿童血清学转换与接触狗之间的高统计学相关性表明，狗通过食用和在猫粪便中打滚，可能在机械传播弓形虫感染中起作用。此外，苍蝇以及在较小程度上蟑螂，可能在传播中发挥重要作用。
