Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.
Sub-Department of Animal Health and Production (SDAHP), Cao Lanh, Vietnam.
Zoonoses Public Health. 2021 Aug;68(5):483-492. doi: 10.1111/zph.12839. Epub 2021 May 2.
Antimicrobials are extensively used both prophylactically and therapeutically in poultry production. Despite this, there are little data on the effect of antimicrobial use (AMU) on disease incidence rate and per cent mortality. We investigated the relationships between AMU and disease and between AMU and mortality using data from a large (n = 322 flocks) cohort of small-scale chicken flocks in the Mekong Delta, Vietnam, that were followed longitudinally from day old to slaughter (5,566 observation weeks). We developed a parameterized algorithm to emulate a randomized control trial from observational data by categorizing the observation weeks into 'non-AMU', 'prophylactic AMU' and 'therapeutic AMU'. To evaluate the prophylactic AMU effect, we compared the frequencies of clinical signs in 'non-AMU' and 'prophylactic AMU' periods. To analyse therapeutic AMU, we compared weekly per cent mortality between the weeks of disease episodes before and after AMU. Analyses were stratified by clinical signs (4) and antimicrobial classes (13). Prophylactic AMU never reduced the probability of disease, and some antimicrobial classes such as lincosamides, amphenicols and penicillins increased the risk. The risk of diarrhoea consistently increased with prophylactic AMU. Therapeutic AMU often had an effect on mortality, but the pattern was inconsistent across the combinations of antimicrobial classes and clinical signs with 14/29 decreasing and 11/29 increasing the per cent weekly mortality. Lincosamides, methenamines and cephalosporins were the only three antimicrobial classes that always decreased the mortality when used therapeutically. Results were robust respective to the parameters values of the weeks categorization algorithm. This information should help support policy efforts and interventions aiming at reducing AMU in animal production.
抗微生物药物在禽类生产中被广泛用于预防和治疗。尽管如此，关于抗微生物药物使用（AMU）对疾病发病率和死亡率的影响的数据却很少。我们使用来自越南湄公河三角洲一个大型（n=322 个鸡群）小规模鸡群的队列数据，对 AMU 与疾病之间以及 AMU 与死亡率之间的关系进行了研究，这些鸡群从雏鸡日龄到屠宰（5566 个观察周）进行了纵向跟踪。我们开发了一种参数化算法，通过将观察周分为“非 AMU”、“预防性 AMU”和“治疗性 AMU”，从观察数据中模拟随机对照试验。为了评估预防性 AMU 的效果，我们比较了“非 AMU”和“预防性 AMU”期间临床症状的频率。为了分析治疗性 AMU，我们比较了 AMU 前后疾病发作期间每周的死亡率。分析按临床症状（4 种）和抗微生物类别（13 种）进行分层。预防性 AMU 从未降低疾病的概率，而某些抗微生物类别，如林可酰胺类、酰胺醇类和青霉素类，增加了风险。预防性 AMU 始终会增加腹泻的风险。治疗性 AMU 通常对死亡率有影响，但在抗微生物类别和临床症状的组合之间模式不一致，有 14/29 种情况降低了每周死亡率，11/29 种情况增加了每周死亡率。林可酰胺类、甲硝哒唑类和头孢菌素类是仅有的三种在治疗时总是降低死亡率的抗微生物类别。结果相对于周分类算法的参数值是稳健的。这些信息应该有助于支持旨在减少动物生产中 AMU 的政策努力和干预措施。
