Cattle Fever Tick Detection by Near Infra-Red Spectroscopy (NIRS) Analysis of Bovine Feces
Obtain daily fecal samples from up to 16 head of cattle; place preconditioned animals tested for internal parasites and testing negative for Babesia species on commercial ration. Collect fecal samples from each animal for 14 days, at which time 8 animals will be infested with Rhipicephalus (Boophilus) microplus. Monitor and record phases of infestation and daily counts of engorged female ticks per animal. Collect fecal samples from each animal (8 infested and 8 non-infested) from day 15 to 45 (tick infestation period), and from day 46 to 60 (recovery phase). Freeze and ship fecal samples to collaborator. Thaw, dry, and mil to 2-mm particle size a portion of the samples, before subjecting to NIRS on a Foss 6500 scanning monochrometer in the 1100-2498 nm range. (Obj. 1) Group Spectra by animal, treatment, and experimental period by date associated with tick feeding phase and yield of engorged ticks and assess differences in magnitude response (Pre-infestation, acute vs chronic phase infestation, and recovery). Organize Spectral data to assess whether a time-lag effect of 1-, 2-, 3-, or 4-days by tick feeding phase improves model fit. Analyze Spectral data using The Unscrambler(R)-X Version 10.3, a chemometric system designed for advanced multivariate analysis of spectral data. Conduct Spectral analysis in collaboration with Range Extension Specialist from the University of Arizona. Benchmark the earliest NIRS detection of tick infestation (Obj. 2) using cluster analysis of NIRS spectra at 3-day intervals beginning with the first-to-third day of infestation and progressing in a stepwise progression through day 60 to determine how soon statistically significant separation between infested and non-infested animals can be detected, and how far into the recovery phase the separation disappears. Assess impact of fecal sample age on NIRS spectral analysis (Obj. 3) by sequentially sampling from approximately 9 kg (20 lbs) of feces collected from tick-infested and non-infested animals on a single day in each of the pre-infestation, acute tick phase, chronic tick phase, and recovery phase. Freeze and ship bulk fecal samples to collaborator. Thaw and Homogenize samples by treatment group and phase, make into 10 "pies" (2" thick x 8" diameter), set in an outdoor environment protected from flies and other insects, and record temperature and humidity on Hobo environmental data loggers. Sample each "pie" daily (1/12 wedge/day) for 12 days. Prepare each sample wedge as above and optically scan and analyze to determine whether there is deterioration in sample quality. Use data to establish viability of NIRS data from aged fecal samples and design standard protocols for collections from paddocks, pastures, trucks or trailers, as may be applied to their forensic interpretations in tick surveillance. Include findings from this project in meta-analyses of more than 16 other data sets that include fNIRS data analyses for infestations of 5 other tick species under laboratory and field conditions to assess the detection of tick-infested cattle and its application in regulatory and IPM programs.