Fascioliasis in buffaloes: A 5-year forecast analysis of the disease based on a 15-year survey in Brazil

Abstract In South America, fascioliasis caused by the trematode Fasciola hepatica is an anthropozoonosis disease associated with significant economic losses and poor animal welfare. The objective of this study was to determine the prevalence of F. hepatica in the liver of buffaloes slaughtered from 2003 to 2017 in Brazil, and to perform a forecast analysis of the disease for the next five years using the Autoregressive Integrated Moving Average (ARIMA) model. Data analysis revealed an incidence of 7,187 cases out of 226,561 individuals. The disease presented a considerable interannual variation (p<0.005). Fasciola hepatica was more prevalent in the southern states of Brazil; Paraná, Rio Grande do Sul, and Santa Catarina, presenting 11.9, 7.7, and 3.2% of infected livers, respectively. The high frequency of liver condemnation in Paraná was influenced by weather conditions. The ARIMA models calculated a constant trend of the disease, depicting an average of its future prevalence. The models also described a worse-case and a positive-case scenario, calculating the effects of intervention measurements. In reality, there is an urgent need for regular diagnostic in the animals (fecal and immune diagnose) and in the environment (intermediate host), in order to avoid the high rates of infection.

摘要：在南美洲，由片形吸虫（Fasciola hepatica）引发的片形吸虫病是一种人兽共患病，与严重经济损失及动物福利水平低下密切相关。本研究旨在明确2003年至2017年间巴西屠宰水牛肝脏感染肝片形吸虫（F. hepatica）的流行情况，并采用自回归积分滑动平均模型（Autoregressive Integrated Moving Average, ARIMA）对该疾病未来五年的流行态势开展预测分析。数据分析显示，在226561头受试水牛中，共检出7187例感染病例；该疾病年际间流行差异显著（p<0.005）。肝片形吸虫感染在巴西南部各州更为高发：巴拉那州、南里奥格兰德州与圣卡塔琳娜州的肝脏感染率分别为11.9%、7.7%与3.2%。巴拉那州肝脏废弃率较高的现象受当地气候条件影响。ARIMA模型显示该疾病流行态势趋于平稳，可预测其未来流行率的平均水平；该模型同时构建了最差情景与最优情景，量化评估了各类干预措施的实施效果。实际上，为遏制高感染率态势，亟需针对动物（粪便与免疫诊断）及环境（中间宿主）开展常态化监测工作。