Collins J B, Choo Rachel, Shaver Amanda O, Schaye Etta S, Volpe Tom, Nunn Lenny, Lighty Megan E, Niel Kayla R, Frye Emily M, Zamanian Mostafa, Andersen Erik C
Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America.
Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America.
bioRxiv. 2025 Aug 13:2025.08.12.669876. doi: 10.1101/2025.08.12.669876.
Ascarid parasites, such as and , are nearly ubiquitous in poultry and can cause serious production losses. is of particular concern because of its role as a vector for the protozoan , the cause of blackhead disease. Currently, only the benzimidazole anthelmintic, fenbendazole (FBZ), is approved for use in poultry, and recently, FBZ resistance has been discovered and validated in populations of the turkey ascarid and in ascarid of gallinaceous birds . Here, we further explore the prevalence of resistance in poultry ascarids by testing FBZ efficacy against thirteen isolates of and eight isolates of . Isolates were used to infect day-old naive chickens. Four weeks after infection, animals to be treated received the label-recommended dosage of FBZ (SafeGuard Aquasol) for five days, per the manufacturer's directions. One week after the fifth day of treatment, animals were euthanized and parasite burdens were counted to determine treatment efficacy between the untreated and treated groups. Resistance was identified and validated in a single isolate of , marking the first confirmed case in the species. All isolates of were found to be resistant. The emergence of resistance in and the high prevalence of resistance in highlight the growing concern of resistance in parasites of poultry. Without approved alternative treatments, the detrimental effects of infections cannot be mitigated in resistant populations, significantly impacting profit margins. Diagnostics that enable broader surveys are necessary to understand the full scope of the problem. However, we show that resistance is present across production species and should act as an impetus for the discovery of new treatments and the adoption of new management strategies.
蛔虫寄生虫，如鸡蛔虫和火鸡蛔虫，在家禽中几乎无处不在，会导致严重的生产损失。火鸡蛔虫尤其值得关注，因为它是原生动物黑头病病原体——黑头组织滴虫的传播媒介。目前，只有苯并咪唑驱虫药芬苯达唑（FBZ）被批准用于家禽，最近，已在火鸡蛔虫种群以及鸡形目鸟类蛔虫中发现并证实了对FBZ的抗性。在此，我们通过测试FBZ对13株鸡蛔虫分离株和8株火鸡蛔虫分离株的疗效，进一步探究家禽蛔虫的抗性流行情况。分离株用于感染1日龄的雏鸡。感染四周后，按照制造商的说明，待治疗的动物接受标签推荐剂量的FBZ（SafeGuard Aquasol），持续五天。治疗第五天之后一周，对动物实施安乐死并计算寄生虫负荷，以确定未治疗组和治疗组之间的治疗效果。在一株鸡蛔虫中鉴定并证实了抗性，这是该物种中首例确诊病例。所有火鸡蛔虫分离株均被发现具有抗性。鸡蛔虫中抗性的出现以及火鸡蛔虫中高抗性流行率凸显了对家禽寄生虫抗性日益增长的担忧。由于没有批准的替代治疗方法，抗性种群中感染的有害影响无法减轻，这将显著影响利润率。需要能够进行更广泛调查的诊断方法来全面了解问题的范围。然而，我们表明抗性存在于所有生产物种中，这应该成为发现新治疗方法和采用新管理策略的动力。
