Ticks and Tick-Borne Pathogens of the Caribbean: Current Understanding and Future Directions for More Comprehensive Surveillance.

Ticks are obligate hematophagous arthropods of significant importance to human and veterinary medicine. They transmit a vast array of pathogens, including bacteria, viruses, protozoa, and helminths. Most epidemiological data on ticks and tick-borne pathogens (TBPs) in the West Indies are limited to common livestock pathogens such as Ehrlichia ruminantium, Babesia spp. (i.e., B. bovis and B. bigemina), and Anaplasma marginale, and less information is available on companion animal pathogens. Of note, human tick-borne diseases (TBDs) remain almost completely uncharacterized in the West Indies. Information on TBP presence in wildlife is also missing. Herein, we provide a comprehensive review of the ticks and TBPs affecting human and animal health in the Caribbean, and introduce the challenges associated with understanding TBD epidemiology and implementing successful TBD management in this region. In particular, we stress the need for innovative and versatile surveillance tools using high-throughput pathogen detection (e.g., high-throughput real-time microfluidic PCR). The use of such tools in large epidemiological surveys will likely improve TBD prevention and control programs in the Caribbean.

Nucleic acid probes as a diagnostic method for tick-borne hemoparasites of veterinary importance.

An increased number of articles on the use of nucleic acid-based hybridization techniques for diagnostic purposes have been recently published. This article reviews nucleic acid-based hybridization as an assay to detect hemoparasite infections of economic relevance in veterinary medicine. By using recombinant DNA techniques, selected clones containing inserts of Anaplasma, Babesia, Cowdria or Theileria genomic DNA sequences have been obtained, and they are now available to be utilized as specific, highly sensitive DNA or RNA probes to detect the presence of the hemoparasite DNA in an infected animal. Either in an isotopic or non-isotopic detection system, probes have allowed scientists to test for--originally in samples collected from experimentally infected animals and later in samples collected in the field--the presence of hemoparasites during the prepatent, patent, convalescent, and chronic periods of the infection in the host. Nucleic acid probes have given researchers the opportunity to carry out genomic analysis of parasite DNA to differentiate hemoparasite species and to identify genetically distinct populations among and within isolates, strains and clonal populations. Prevalence of parasite infection in the tick vector can now be accomplished more specifically with the nucleic acid probes. Lately, with the advent of the polymerase chain reaction technique, small numbers of hemoparasites can be positively identified in the vertebrate host and tick vector. These techniques can be used to assess the veterinary epidemiological situation in a particular geographical region for the planning of control measures.

Effect of acaricide treatment of cattle on Amblyomma variegatum (Acari: Ixodidae) infestation of mongooses (Carnivora: Viverridae: Herpestes auropunctatus) in Guadeloupe, French West Indies.

The effect of acaricide treatment of cattle on the infestation of the small Indian mongoose (Herpestes auropunctatus Hodgson) by Amblyomma variegatum (F.) was determined during a field evaluation of selected acaricides in Guadeloupe, French West Indies. From April 1990 to April 1991, cattle at one site were treated every 14 d with pour-on formulations of deltamethrin, flumethrin, or permethrin; and cattle at a second site were treated as per a local standard treatment using a spray formulation of coumaphos every 30 d. The protocol was then reversed, and from April to July 1991 cattle at the original standard treatment site were treated using the pour-on treatment. Mongooses were examined for ticks during February-March and July 1990 and 1991. The mean prevalence of infestation of mongooses by A. variegatum larvae was reduced from 41 to 27% during the February-March to July periods at the pour-on treatment sites but increased from 29 to 43% during the same periods at the standard treatment sites. The mean relative density of infestation by larvae decreased from 2.15 to 0.65 at the pour-on treatment sites and increased from 0.7 to 1.95 at the standard treatment sites during the same periods. Data on nymphal infestations were inconclusive, and mongooses were not infested by adult ticks. The infestation of mongooses by A. variegatum may be of importance as a short-term alternative host system for immature stages of this tick during an eradication program.