Progress Towards the Eradication of Amblyomma variegatum from the Caribbean

Abstract

Progress in the Caribbean Amblyomma Program (CAP) is reviewed since its inception in 1995 when regional eradication activities for Amblyomma variegatum ticks were initiated using Bayticol pour-on. Technical achievements in the various islands were slow initially, and showed a wide diversity in attaining eradication targets. St. Kitts, considered as a model program. eliminated the tropical Bont tick (TBT) from most of the island in less than 3 years. However, the elimination of very low numbers of residual adult TBT that persisted in three 'hot-spots' took another 3 years. A similar problem was faced in St. Lucia, although the approach there was to cull the wild cattle in the last remaining hot-spot. Both islands were certified as 'Provisionally free from TBT' in November 2001. In 2002, Anguilla and Montserrat attained the same status, and Barbados and Dominica also qualify for certification. Certification is based on strict, three-monthly, surveillance criteria: essentially, two successive TBT-free surveillance rounds on a statistically acceptable sample of the livestock population. Within the responsibility of the CAP, three islands remain TBT-infested, Antigua, Nevis, and St. Martin/St. Maarten. Nevis is of concern because it has been operational since late 1995, and appears unable to resolve the problem of treating stray small ruminants. Current funding should be adequate to complete eradication on Nevis and in St. Martin/St. Maarten. The major outstanding challenge is Antigua. In comparison to other islands they have the largest number of livestock, and have much larger populations than originally reported: sheep and goats are 4-5-fold higher, and cattle are 1.35-fold higher. The cost for Bayticol is, therefore, almost double and an additional US dollars 1.5 million is required for that commodity alone.

The effect of host vicariance and parasite life history on the dispersal of the multi‐host ectoparasite, Hyalomma truncatum

“…In contrast, all life stages of A. variegatum can feed on large-bodied ruminants, and as such, the presence of smaller wildlife species is not a requirement (Barr e et al, 1995). In addition, the immature stages can also adapt to the availability of hosts in an area as they are also often found on birds, even when mammals are present (Barr e & Garris, 1990;Pegram & Eddy, 2002). Accordingly, it seems reasonable to argue that the higher level of genetic population differentiation found in H. truncatum, when compared to the published data on A. variegatum (Beati et al, 2012), is due to a higher level of host specificity in the former species coupled to the lower mobility of hosts for the immature stages (small mammals).…”

Will climate change affect ectoparasite species ranges?

“…Our maps of current habitat suitability suggest a high likelihood of several specific invasions that in fact have already occurred. For example, the African tick A. variegatum, an important and widespread vector species in Africa, invaded a number of Caribbean islands including Puerto Rico, St Croix, Guadeloupe, Martinique, St Kitts and St Lucia (Uilenberg et al, 1984;Walker & Olwage, 1987;Pegram & Eddy, 2002). With assistance from the United States Department of Agriculture (USDA), the tick has since been eradicated from many of these areas at great expense (Pegram & Eddy, 2002).…”

“…For example, the African tick A. variegatum, an important and widespread vector species in Africa, invaded a number of Caribbean islands including Puerto Rico, St Croix, Guadeloupe, Martinique, St Kitts and St Lucia (Uilenberg et al, 1984;Walker & Olwage, 1987;Pegram & Eddy, 2002). With assistance from the United States Department of Agriculture (USDA), the tick has since been eradicated from many of these areas at great expense (Pegram & Eddy, 2002). Eradication of A. variegatum from the small island of Antigua was expected to cost over US$1.5 million for pesticides alone (Pegram & Eddy, 2002).…”

“…With assistance from the United States Department of Agriculture (USDA), the tick has since been eradicated from many of these areas at great expense (Pegram & Eddy, 2002). Eradication of A. variegatum from the small island of Antigua was expected to cost over US$1.5 million for pesticides alone (Pegram & Eddy, 2002). The increasing susceptibility of many island nations to invasion by African ticks is of high concern, given the apparently high vulnerability of island faunas to exotic diseases and parasites (Wikelski et al, 2004), and the many rare and endemic species that islands harbour.…”

Eradication and control of livestock ticks: biological, economic and social perspectives

“…Culling the feral hosts was impossible and treating the ovine hosts was inefficient, so emphasis was placed on the favoured status of cattle as the maintenance host for A. variegatum . Unfortunately, some cattle were almost impossible to treat, even with pour-on acaricide, due to the meagre resources for managing the cattle (Pegram and Eddy, 2002; Pegram, 2010).…”