Quantification of vertical and horizontal transmission of Neospora caninum infection in Dutch dairy herds
Quantification of vertical and horizontal transmission of Neospora caninum infection in Dutch dairy herds
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DOI：
10.1016/j.vetpar.2007.06.004
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发表时间：
2007-09-01
影响因子：
2.6
通讯作者：
Stegeman, Arjan
中科院分区：
文献类型：
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作者：
Bartels, Cbxis J. M.;Huinink, Irene;Stegeman, Arjan
96的108个随机选择的荷兰奶牛群有一个或多个奶牛的阳性血清状态为N.犬。在这96个牛群中。我们通过结合4091对母鼠-子代的血清学状态和系谱数据，量化了犬奈瑟氏菌感染的垂直传播（VT）和水平传播（HT）的概率。妊娠期间垂直传播感染动物的概率（Prob（VT））计算为血清阳性母鼠的女儿中血清阳性女儿的比例。水平传播感染动物的概率（Prob（HT））是血清阴性母鼠的子代中血清阳性子代的比例。在对观察到的母鼠-子代组合的频率进行校正后，计算了这些概率：（1）不完善的测试特征，（2）在血清阴性母鼠在其女儿出生后水平感染的情况下低估了水平传播，以及（3）在血清阴性母鼠出生的血清阴性女儿水平感染的情况下高估了垂直传播。根据Prob（HT）和牛群平均年龄计算水平传播发病率，母-子血清学分析，Prob（VT）为61.8%（95% CI：57.5-66.0%），Prob（HT）为3.3%（95% CI：2.7-3.917%）。在调整观察到的频率不完美的测试特征，水平传输的低估和垂直传输的高估，概率（VT）下降到44.9%（95% CI：40.0-49.9%），而概率（HT）增加到4.5%（95% CI：3.9-5.2%）。概率（HT）对应水平传播的发生率为1.4（95%CI：1.2-1.7）感染/100牛耳的风险。当分层牛群的农场狗的存在，概率（FIT）较高（5.5%（95% CI：4.6-6.4%）），而在无农场犬的牛群中（2.3%（95% CI：1.5-3.4%））。当对畜群内血清阳性率进行分层时，与畜群内血清阳性率低（< 10%）的畜群（2.0%（95% CI：1.5-2.6%））相比，畜群内血清阳性率高（>= 10%）的畜群的Prob（HT）较高（10.3%（95% CI：8.6- 12.2%））。尽管Prob（HT）和畜群内血清阳性率之间存在这种关系（粗ORPREV = 5.7（95% CI：4.0-7.9）），但在没有农场犬的畜群中，这种关系不再具有统计学显著性（ORPREVIDOG = 1-9（95% CI：0.7-5.5））。提示Prob（HT）与血清阳性率的相关性在很大程度上依赖于家犬的存在。当寻找血清阳性率明显高于畜群其他动物的特定年龄组时，有7个畜群在特定年龄组中存在两只或两只以上水平感染的动物。这表明最近曾接触过犬新诺菌的点源。
Ninety-six of 108 randomly selected Dutch dairy herds had one or more cows with a positive serostatus for N.canintan. In these 96 herds. we have quantified the probabilities of vertical transmission (VT) and horizontal transmission (HT) of N.caninum infection by combining serostatus and pedigree data in 4091 dam-daughter pairs. The probability of animals infected by vertical transmission during pregnancy (Prob(VT)) was calculated as the proportion of seropositive daughters among daughters of seropositive dams. The probability of animals infected by horizontal transmission (Prob(HT)) was the proportion of seropositive daughters among daughters of seronegative dams. These probabilities were calculated after the frequencies of observed dam-daughter combinations were corrected for (1) imperfect test-characteristics, (2) underestimation of horizontal transmission in situations that seronegafive dams were horizontally infected after the birth of their daughters and (3) overestimation of vertical transmission in situations that seronegative daughters born from seropositive dams were horizontally infected. The incidence rate for horizontal transmission was calculated based on Prob(HT) and the average age of the animals in these herds.Based on the analysis of dam-daughter serology, Prob(VT) was 61.8% (95% CI: 57.5-66.0%) and Prob(HT) was 3.3% (95% CI: 2.7-3.917%). After adjusting the observed frequencies for imperfect test-characteristics, underestimation of horizontal transmission and overestimation of vertical transmission, Prob(VT) decreased to 44.9% (95% CI: 40.0-49.9%) while Prob(HT) increased to 4.5% (95% CI: 3.9-5.2%). Prob(HT) corresponded with an incidence rate for horizontal transmission of 1.4 (95% CI: 1.2-1.7) infections per 100 cow-ears at risk.When stratifying herds for the presence of farm dogs, Prob(FIT) was higher (5.5% (95% CI: 4.6-6.4%)) in herds with farm dogs than in herds without farm dogs (2.3% (95% CI: 1.5-3.4%)). When stratifying for within-herd seroprevalence, Prob(HT) was higher (10.3% (95% CI: 8.6-12.2%)) in herds with high (>= 10%) within-herd seroprevalence compared with herds with low (< 10%) within-herd seroprevalence (2.0% (95% CI: 1.5-2.6%)). Although there was this relation between Prob(HT) and within-herd seroprevalence (crude ORPREV = 5.7 (95% CI: 4.0-7.9)), in herds without farm dogs, this relationship was no longer statistical significant (ORPREVIDOG = 1-9 (95% CI: 0.7-5.5)). It indicated that the association between seroprevalence and Prob(HT) depended largely on the presence of farm dogs.In addition. when looking for the presence of specific age-groups with significantly higher seroprevalence compared with the rest of the herd, there were 7 herds in which two or more horizontally-infected animals were present in specific age-groups. This was an indication of a recent point-source exposure to N.caninum.