Determination of acaricide resistance in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) field populations of Argentina, South Africa, and Australia with the Larval Tarsal Test.

Infestations with ticks have an important economic impact on the cattle industry worldwide and resistance to acaricides has become a widespread phenomenon. To optimize their treatment strategy, farmers need to know if and against which classes potential acaricide-resistance does occur. Bioassays are used to assess the resistance level and pattern of Rhipicephalus (Boophilus) microplus populations. The objective of the current study was to assess the susceptibility of field populations originating from Argentina (8), South Africa (3), and Australia (2) using the Larval Tarsal Test. Nine acaricidal compounds from five major classes were tested: organosphosphates, synthetic pyrethroids (SP), macrocyclic lactones, phenylpyrazols, and amidines. The resistance ratios at concentrations inducing 50 and 90% mortality were used to detect established and emerging resistance. This study confirmed the newly reported presence of amitraz resistance in populations from Argentina In addition, resistance to SP appeared to be widespread (88%) in the Argentinean farms, which had been selected based on the observation of lack of treatment efficacy by farmers. In South Africa one of the three populations was found to be resistant to SP and to a phenylpyrazol compound (pyriprol). Furthermore, resistance to organosphosphates and SP was observed in Australia. Finally, the Larval Tarsal Test proved to be a suitable test to evaluate the susceptibility of R. microplus field populations to the most relevant acaricidal classes.

Ipsilateral limbal translocation for treatment of partial limbal deficiency secondary to ocular alkali burn.

BACKGROUND/AIM: Chemical ocular burn, especially by alkali, may result in damage to the limbal stem cells, fundamental in maintaining the integrity of ocular surface. Clinically, patients manifest abnormal conjunctival-corneal healing with peripheral neovessels, chronic epithelial defect, severe stromal inflammation, and conjunctivalisation of the corneal, which is characteristic of limbal deficiency. Penetrating keratoplasty has a poor prognosis in these cases. Available therapeutic options included limbal autograft and allograft transplantation associated or not with human amniotic membrane transplant. The authors propose an alternative treatment with ipsilateral autologous limbal transplantation, transferring the healthy portion of the limbus from the partially burned eye to the deficient area in patients with partial limbal deficiency secondary to alkali burn. METHODS: Ipsilateral limbal autografts were performed in five patients with partial limbal deficiency secondary to alkali burn, transferring the healthy portion of the limbus to the burned area of the same eye, without intervening in the contralateral eye. RESULTS: All cases had regression of the limbal deficiency with improvement of visual acuity to a minimum of 20/60-20/20 (partial), without complications during the follow up period (range 7-11 months). CONCLUSION: Ipsilateral autologous limbal autograft is a therapeutic option for partial limbal deficient eyes.