Berentsen Are R, Sugihara Robert T, Payne Cynthia G, Leinbach Israel, Volker Steven F, Vos Ad, Ortmann Steffen, Gilbert Amy T
US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center;
US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center.
J Vis Exp. 2019 May 31(147). doi: 10.3791/59373.
The small Indian mongoose (Herpestes auropunctatus) is a reservoir of rabies virus (RABV) in Puerto Rico and comprises over 70% of animal rabies cases reported annually. The control of RABV circulation in wildlife reservoirs is typically accomplished by a strategy of oral rabies vaccination (ORV). Currently no wildlife ORV program exists in Puerto Rico. Research into oral rabies vaccines and various bait types for mongooses has been conducted with promising results. Monitoring the success of ORV relies on estimating bait uptake by target species, which typically involves evaluating a change in RABV neutralizing antibodies (RVNA) post vaccination. This strategy may be difficult to interpret in areas with an active wildlife ORV program or in areas where RABV is enzootic and background levels of RVNA are present in reservoir species. In such situations, a biomarker incorporated with the vaccine or the bait matrix may be useful. We offered 16 captive mongooses placebo ORV baits containing ethyl-iophenoxic acid (et-IPA) in concentrations of 0.4% and 1% inside the bait and 0.14% in the external bait matrix. We also offered 12 captive mongooses ORV baits containing methyl-iophenoxic acid (me-IPA) in concentrations of 0.035%, 0.07% and 0.14% in the external bait matrix. We collected a serum sample prior to bait offering and then weekly for up to eight weeks post offering. We extracted Iophenoxic acids from sera into acetonitrile and quantified using liquid chromatography/mass spectrometry. We analyzed sera for et-IPA or me-IPA by liquid chromatography-mass spectrometry. We found adequate marking ability for at least eight and four weeks for et- and me-IPA, respectively. Both IPA derivatives could be suitable for field evaluation of ORV bait uptake in mongooses. Due to the longevity of the marker in mongoose sera, care must be taken to not confound results by using the same IPA derivative during consecutive evaluations.
印度小獴（食蟹獴）是波多黎各狂犬病病毒（RABV）的储存宿主，占每年报告的动物狂犬病病例的70%以上。控制野生动物储存宿主中狂犬病病毒的传播通常通过口服狂犬病疫苗（ORV）策略来实现。目前波多黎各没有野生动物ORV项目。已对用于獴的口服狂犬病疫苗和各种诱饵类型进行了研究，取得了有希望的结果。监测ORV的成功依赖于估计目标物种对诱饵的摄取情况，这通常涉及评估接种疫苗后狂犬病病毒中和抗体（RVNA）的变化。在有活跃的野生动物ORV项目的地区或狂犬病地方流行且储存宿主物种中存在RVNA背景水平的地区，这种策略可能难以解释。在这种情况下，与疫苗或诱饵基质结合的生物标志物可能会有用。我们给16只圈养的獴投喂了含有乙碘苯氧酸（et-IPA）的安慰剂ORV诱饵，诱饵内部浓度为0.4%和1%，外部诱饵基质中浓度为0.14%。我们还给12只圈养的獴投喂了外部诱饵基质中含有浓度为0.035%、0.07%和0.14%的甲碘苯氧酸（me-IPA）的ORV诱饵。在投喂诱饵前采集血清样本，然后在投喂后每周采集一次，持续长达八周。我们将血清中的碘苯氧酸提取到乙腈中，并使用液相色谱/质谱法进行定量。我们通过液相色谱-质谱法分析血清中的et-IPA或me-IPA。我们发现et-IPA和me-IPA分别至少在八周和四周内具有足够的标记能力。两种IPA衍生物都可能适用于獴对ORV诱饵摄取情况的现场评估。由于标记物在獴血清中的持久性，在连续评估期间使用相同的IPA衍生物时必须小心，以免混淆结果。
