Department of Bioinformatics, Epidemiology and Animal Models, Wageningen Bioveterinary Research, Lelystad, the Netherlands.
Department of Bacteriology, Host-Pathogen Interactions and Diagnostic Development, Wageningen Bioveterinary Research, Lelystad, the Netherlands.
Microbiol Spectr. 2023 Jun 15;11(3):e0255322. doi: 10.1128/spectrum.02553-22. Epub 2023 May 24.
The susceptibility of domestic cats to infection with SARS-CoV-2 has been demonstrated by several experimental studies and field observations. We performed an extensive study to further characterize the transmission of SARS-CoV-2 between cats, through both direct and indirect contact. To that end, we estimated the transmission rate parameter and the decay parameter for infectivity in the environment. Using four groups of pair-transmission experiment, all donor (inoculated) cats became infected, shed virus, and seroconverted, while three out of four direct contact cats got infected, shed virus, and two of those seroconverted. One out of eight cats exposed to a SARS-CoV-2-contaminated environment became infected but did not seroconvert. Statistical analysis of the transmission data gives a reproduction number of 2.18 (95% CI = 0.92 to 4.08), a transmission rate parameter β of 0.23 day (95% CI = 0.06 to 0.54), and a virus decay rate parameter μ of 2.73 day (95% CI = 0.77 to 15.82). These data indicate that transmission between cats is efficient and can be sustained ( > 1), however, the infectiousness of a contaminated environment decays rapidly (mean duration of infectiousness 1/2.73 days). Despite this, infections of cats via exposure to a SARS-CoV-2-contaminated environment cannot be discounted if cats are exposed shortly after contamination. This article provides additional insight into the risk of infection that could arise from cats infected with SARS-CoV-2 by using epidemiological models to determine transmission parameters. Considering that transmission parameters are not always provided in the literature describing transmission experiments in animals, we demonstrate that mathematical analysis of experimental data is crucial to estimate the likelihood of transmission. This article is also relevant to animal health professionals and authorities involved in risk assessments for zoonotic spill-overs of SARS-CoV-2. Last but not least, the mathematical models to calculate transmission parameters are applicable to analyze the experimental transmission of other pathogens between animals.
家猫感染 SARS-CoV-2 的易感性已被多项实验研究和现场观察所证实。我们进行了广泛的研究，以进一步描述 SARS-CoV-2 在猫之间通过直接和间接接触的传播。为此，我们估计了感染率参数和环境中传染性的衰减参数。通过四组成对传播实验，所有供体（接种）猫均感染、排毒并血清转换，而四只有直接接触的猫中有三只感染、排毒，其中两只血清转换。八只暴露于 SARS-CoV-2 污染环境的猫中只有一只感染但未血清转换。对传播数据的统计分析给出了繁殖数 2.18（95%置信区间=0.92 至 4.08），传播率参数β为 0.23 天（95%置信区间=0.06 至 0.54），病毒衰减率参数μ为 2.73 天（95%置信区间=0.77 至 15.82）。这些数据表明，猫之间的传播是有效的并且可以持续（>1），然而，污染环境的传染性迅速衰减（传染性半衰期为 1/2.73 天）。尽管如此，如果猫在污染后不久暴露于 SARS-CoV-2 污染的环境中，仍不能排除猫通过暴露于 SARS-CoV-2 污染的环境而感染的可能性。本文通过使用流行病学模型来确定传播参数，为感染 SARS-CoV-2 的猫可能带来的感染风险提供了更多的见解。考虑到描述动物传播实验的文献中并非总是提供传播参数，我们证明了对实验数据进行数学分析对于估计传播的可能性至关重要。本文对于涉及 SARS-CoV-2 动物溢出风险评估的动物卫生专业人员和当局也具有重要意义。最后但同样重要的是，用于计算传播参数的数学模型可适用于分析其他病原体在动物之间的实验传播。
