Foot and Mouth Disease National Laboratory, Embakasi, Directorate of Veterinary Services, State Department of Livestock, Nairobi, Kenya.
Department of Veterinary Pathology, Microbiology and Parasitology, University of Nairobi, Nairobi, Kenya.
PLoS One. 2021 Aug 2;16(8):e0234286. doi: 10.1371/journal.pone.0234286. eCollection 2021.
Foot-and-mouth disease (FMD) is endemic in Kenya affecting cloven-hoofed ruminants. The epidemiology of the disease in small ruminants (SR) in Kenya is not documented. We carried out a cross-sectional study, the first in Kenya, to estimate the sero-prevalence of FMD in SR and the associated risk factors nationally. Selection of animals to be sampled used a multistage cluster sampling approach. Serum samples totaling 7564 were screened for FMD antibodies of non-structural-proteins using ID Screen® NSP Competition ELISA kit. To identify the risk factors, generalized linear mixed effects (GLMM) logistic regression analysis with county and villages as random effect variables was used. The country animal level sero-prevalence was 22.5% (95% CI: 22.3%-24.3%) while herd level sero-prevalence was 77.6% (95% CI: 73.9%-80.9%). The risk factor that was significantly positively associated with FMD sero-positivity in SR was multipurpose production type (OR = 1.307; p = 0.042). The risk factors that were significantly negatively associated with FMD sero-positivity were male sex (OR = 0.796; p = 0.007), young age (OR = 0.470; p = 0.010), and sedentary production zone (OR = 0.324; p<0.001). There were no statistically significant intra class correlations among the random effect variables but interactions between age and sex variables among the studied animals were statistically significant (p = 0.019). This study showed that there may be widespread undetected virus circulation in SR indicated by the near ubiquitous spatial distribution of significant FMD sero-positivity in the country. Strengthening of risk-based FMD surveillance in small ruminants is recommended. Adjustment of husbandry practices to control FMD in SR and in-contact species is suggested. Cross-transmission of FMD and more risk factors need to be researched.
口蹄疫（FMD）在肯尼亚流行，影响偶蹄目反刍动物。肯尼亚小反刍动物（SR）的疾病流行病学尚未记录。我们进行了横断面研究，这是肯尼亚首次进行的研究，以估计全国范围内 SR 中 FMD 的血清流行率和相关风险因素。动物抽样选择采用多阶段聚类抽样方法。使用 ID Screen®NSP 竞争 ELISA 试剂盒，对总计 7564 份血清样本进行非结构蛋白 FMD 抗体筛查。为了确定风险因素，我们使用广义线性混合效应（GLMM）逻辑回归分析，以县和村庄作为随机效应变量。该国动物血清流行率为 22.5%（95%CI：22.3%-24.3%），而畜群血清流行率为 77.6%（95%CI：73.9%-80.9%）。与 SR 中 FMD 血清阳性显著正相关的风险因素是多用途生产类型（OR = 1.307；p = 0.042）。与 FMD 血清阳性显著负相关的风险因素是雄性（OR = 0.796；p = 0.007）、年龄较小（OR = 0.470；p = 0.010）和静止生产区（OR = 0.324；p<0.001）。随机效应变量之间没有统计学上显著的类内相关，但研究动物的年龄和性别变量之间存在统计学显著的相互作用（p = 0.019）。本研究表明，SR 中可能存在广泛未检测到的病毒循环，该国普遍存在显著的 FMD 血清阳性表明了这一点。建议加强小反刍动物基于风险的 FMD 监测。建议调整畜牧业做法以控制 SR 和接触物种中的 FMD。需要研究 FMD 的跨传播和更多风险因素。
