Population dynamics of the cattle tick Rhipicephalus (Boophilus) microplus in a subtropical subhumid region of Argentina for use in the design of control strategies

Abstract

The population dynamics of Rhipicephalus microplus (Ixodida: Ixodidae) in northwest Argentina was analysed to support the design of strategic methods for its control. Both parasitic and non-parasitic phases were studied. The seasonal activity of R. microplus in its parasitic phase was characterized by three peaks in abundance: the first in mid-late spring; the second in summer, and the third in autumn. The non-parasitic phase of R. microplus was characterized by a long total non-parasitic period observed after exposures of females from mid-summer to early autumn, a short total non-parasitic period observed after exposures of females from late winter to late spring, a short period of larval longevity in early and mid-summer, and no hatch of the eggs produced by females exposed in mid- and late autumn and winter. Treatments of cattle administered during the period from late winter to late spring will act on small cohorts of R. microplus, preventing the emergence of larger generations in summer and autumn. A 17-week spelling period starting in late spring and early summer will be necessary to achieve optimal control of R. microplus free-living larvae. If spelling begins in mid- or late summer or in autumn, the required period will be 26-27 weeks.

Prevalence and genetic characterization of Giardia spp. and Cryptosporidium spp. in dogs in Iqaluit, Nunavut, Canada

“…In this study, DNA was amplified by PCR for one of the parasites even if the preceding parasitological tests were negative for that parasite. Other researchers have concluded that discordance among testing modalities is common (Decock, Cadiergues, Larcher, Vermot, & Franc, 2003;Dryden, Payne, & Smith, 2006;Geurden, Berkvens, Casaert, Vercruysse, & Claerebout, 2008;Leonhard, Pfister, Beelitz, Wielinga, & Thompson, 2007;McDowall et al, 2011;Olson et al, 2010), and that identifying and genotyping G. intestinalis can be challenging (Lebbad et al, 2010;Leonhard et al, 2007;McDowall et al, 2011), all of which may indicate that our prevalence estimates are likely underestimates. Our study highlights some of the realistic challenges that exist with collecting faecal samples in a remote Arctic locale, maintaining correct sample storage conditions and facilitating rapid analysis at a centralized southern laboratory.…”

“…The faecal immunoassays would be expected to detect a Giardia spp. infection despite the lack of shedding of intact parasites (Olson, Leonard, & Strout, 2010). Finally, there were numerical differences among parasitological tests and discordance between parasitological test results and PCR results.…”

“…The diagnosis of Giardia spp. using faecal flotation can be difficult as cysts are small and similar in appearance to many pseudoparasites such as yeast, which can result in an underestimation or overestimation of prevalence (Olson et al, 2010). For the rapid immunoassays, both manufacturers report high sensitivities and specificities: the IDEXX SNAP ® Giardia test boasts 89.2% sensitivity and 100% specificity, whereas the Xpect™ Giardia/Cryptosporidium test has 95.8%-96.4% sensitivity and 98.5% specificity (IDEXX Veterinary Diagnostics, Westbrook, 2016;Thermofisher Scientific, 2016).…”

Quantitative models of Rhipicephalus (Boophilus) ticks: historical review and synthesis

“…The reinstatement of R. australis as a sibling species of R. microplus , Guglielmone et al 2014) has spurred new ecological studies of R. microplus in South America (Canevari et al 2016). It may also spur reconsideration of past model predictions and revision of existing models, especially those that used data from one species to represent the other species, or those developed by merging data from both species together.…”

Brotes de babesiosis y anaplasmosis bovina diagnosticados en el INTA Salta, Argentina: período 2006-2016

“…Acorde con nuestros datos este autor registró al trimestre agosto-octubre como el de menor cantidad de brotes de TPB. Este bache en la casuística se explicaría al menos para las babesiosis-por la nula eclosión de huevos de R. microplus durante el invierno, señalada recientemente para distintos sitios del NOA (Canevari et al, 2016;Mastropaolo et al, 2017). A su vez, el predominio de A. marginale y B. bovis aquí mencionado coincide también con lo descripto por Sarmiento y Zimmer (2010) para brotes ocurridos en la provincia de Corrientes durante un breve lapso (2009)(2010).…”