National Veterinary Institute, 751 89 Uppsala, Sweden.
BMC Vet Res. 2012 Jan 26;8:9. doi: 10.1186/1746-6148-8-9.
Within the genera Chlamydia, the development of refined diagnostic techniques has allowed the identification of four species that are capable of infecting pigs. The epidemiology, clinical, and zoonotic impacts of these species are however largely unknown. The study aimed to investigate the presence of Chlamydia spp. in the intestines of growing pigs and in conjunctival swabs from finisher pigs, and relate the findings to clinical signs.
By histology, 20 of 48 pigs had intestinal lesions that may be consistent with chlamydial infection. By PCR, forty-six of the pigs were positive whereas two samples were inhibited. Sequencing of 19 DNA extracts identified these as Chlamydia suis. By immunohistochemistry, 32 of 44 samples were positive and a significant relationship was detected between macroscopically visible intestinal lesions and a high degree of infection. By real-time PCR, a significant difference was detected between pigs with and without conjunctivitis when a Ct value of 36 was employed but not when a Ct value of 38 was employed.
Chlamydia suis was demonstrated in most samples and overall, no correlation to clinical signs was detected. However, a correlation was noted between samples with a high degree of infection and the presence of clinical signs. It is possible, that the intensive pig production systems studied might predispose for the transmission and maintenance of the infection thus increasing the infectious load and the risk for disease in the pig.
在衣原体属中，精细诊断技术的发展已经能够鉴定出四种能够感染猪的物种。然而，这些物种的流行病学、临床和人畜共患病的影响在很大程度上还不得而知。本研究旨在调查生长猪肠道和育肥猪眼结膜拭子中是否存在衣原体属，并将调查结果与临床症状联系起来。
通过组织学，48 头猪中有 20 头具有可能与衣原体感染一致的肠道病变。通过 PCR，46 头猪呈阳性，而两个样本受到抑制。对 19 个 DNA 提取物的测序将这些鉴定为猪衣原体。通过免疫组织化学，44 个样本中有 32 个呈阳性，并且在肉眼可见的肠道病变和高度感染之间检测到显著的相关性。通过实时 PCR，当使用 Ct 值 36 时，在有和没有结膜炎的猪之间检测到显著差异，但当使用 Ct 值 38 时则没有检测到。
在大多数样本中均检测到猪衣原体，并且总体上未检测到与临床症状相关。然而，在高度感染的样本中观察到与临床症状存在相关性。在研究的集约化养猪系统中，感染的传播和维持可能更容易发生，从而增加猪的感染负荷和患病风险。
