PubMed Health⌕ Search

Biomedical subjects

G I Garris

Publications and source records attributed to G I Garris.

At least 19 recordsLinked to original sources
PubMed1997

Field sampling of the tick Amblyomma variegatum (Acari: Ixodidae) on pastures in Guadeloupe; attraction of CO2 and/or tick pheromones and conditions of use.

Field experiments were conducted in Guadeloupe to evaluate the attraction of different chemicals on a Guadeloupean strain of Amblyomma variegatum. Such tick sampling techniques may help to assess the size of the tick population on pastures before, during and after an attempted tick eradication campaign. CO2 was absolutely necessary to activate ticks, including the larvae. In addition to activation, our data suggested that CO2 itself is attractive for ticks. The reactivity of the ticks varied greatly with the period of the year, the adults being insensitive to CO2 alone or combined with pheromones for a period extending from December to June. For the whole period, the total captures were equal for the males and females, but the males were relatively more sensitive at the beginning of the season of activity (June-July), while the females dominated, but not significantly, for the rest of the period. There was also a gradient of reactivity depending on the distance from the trap; 28% of the ticks were captured at 0.5 m from the CO2 traps and 1.2% at a distance of 6 m. The ticks arrived rapidly at the trap. After 1 h of trapping, 55, 68 and 81% of the active nymphs, males and females, respectively, had reached the trap. Synthetic pheromones (methyl salicylate, o-nitrophenol and nonanoic acid in the proportions 1:2:8) or freshly detached males added to CO2, greatly increased the efficacy of the CO2 traps. Depending on the concentration of the pheromones, the attraction was four to 70 times higher than with CO2 alone. The effect depended on the sex of the ticks, males being attracted in a greater proportion by small amounts of pheromones, while the females were activated by higher doses. From a practical point of view, sampling should be conducted from June to December, with CO2 and high concentrations of pheromones, the traps being in operation for approximately 1 h at least, the area concerned by effluents being located downwind and covering an area of approximately 36 m2.

Age Factors↗
PubMed1996

Potential impact of wildlife on the tropical bont tick eradication program in the Caribbean.

Wildlife are hosts for A. variegatum throughout its range in Africa, and have been demonstrated to serve as hosts for larvae and nymphs on several islands in the Caribbean. Studies conducted in the Caribbean have indicated that most larvae and nymphs and all adults of the tick feed on livestock; therefore, eradication can be approached through the treatment of livestock. However, since small numbers of animals such as the mongoose are infested with larvae and nymphs, these animals may represent a short-term alternative host system. Such infestations potentially could result in a presence of small numbers of ticks for up to 46 months after the onset of a treatment program and could serve as a source to reinfest livestock during the eradication process. Wildlife surveys have been conducted in St. Croix, Puerto Rico, Guadeloupe, and Antigua; but the host status of species present on other islands such as the white-tailed deer on St. Kitts has not been evaluated. As part of the eradication program, the species of wildlife present on each island and the association of these species with infested pastures should be determined. Surveys of wildlife can be used during the eradication to determine if wildlife are serving as an alternative host system. Cattle egrets may serve to disseminate the tick among islands in the region, and to areas outside the region. Cattle egrets have been shown to serve as hosts for the tick, and to move throughout the eastern Caribbean and to North America. The potential for interisland dissemination of ticks by cattle egrets, as well as by other means, substantiates the need for a region-wide eradication program.

Animals↗
PubMed1996

Development of a computer model of the population dynamics of Amblyomma variegatum and simulations of eradication strategies for use in the Caribbean.

Control or eradication efforts should cover wide areas because of long-range migration potential of immature ticks attached to birds, such as cattle egrets. Careful follow-up inspections are also imperative. Simulation 1 shows how rapidly the population numbers may expand from small numbers, either introduced or missed. Simulation 4 indicates extending the treatment cycle beyond the residual effectiveness of the acaricide to save labor or funds would be false economy. The result could be to maintain the tick population indefinitely, with an accompanying increase in long-term control costs. Simulations 2 and 3 indicate that eradication is possible if response is prompt and the treatment cycle is less than the period of residual effectiveness of the acaricide used.

Animals↗
PubMed1994

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.

Acari↗
PubMed1993

Potential role of cattle egrets, Bubulcus ibis (Ciconiformes: Ardeidae), in the dissemination of Amblyomma variegatum (Acari: Ixodidae) in the eastern Caribbean.

The potential role of cattle egrets, Bubulcus ibis (L.), in the dissemination of Amblyomma variegatum (F.) in the eastern Caribbean was evaluated. The status of cattle egrets as hosts for A. variegatum in Antigua was determined during seven survey periods between September 1988 and May 1991. The mean prevalences of infestation by larvae and nymphs were 2.3 and 0.5%, respectively. The mean intensity and relative density of infestation by larvae were 8.8 (SD = 9.80) and 0.2 (SD = 0.28), respectively. Cattle egrets examined in Guadeloupe during February-March 1991 were not infested but 5.9% were infested by larvae during June-July 1991. Interisland movement of cattle egrets was evaluated relative to emigration of birds captured and marked in Antigua and Guadeloupe. During this aspect of the study, 1,129 cattle egrets were captured, marked, and released. Of 195 sighting reports received, 56 were determined to be independent sightings. Emigration of cattle egrets included movement of birds marked in Antigua or Guadeloupe to 14 Caribbean islands and the Florida Keys. Interisland movement occurred in each of the discrete observation periods during the 3-yr study period. The rate of emigration per period ranged from 1.2 to 12.9%. That cattle egrets served as hosts for immature A. variegatum in the eastern Caribbean and moved between islands in the region demonstrates that these birds could serve as disseminators of the tick. Estimates of the numbers of infested cattle egrets emigrating from Antigua and Guadeloupe ranged from 0 to 0.24% of the current populations.

Animals↗
PubMed1993

Progress towards a program for the eradication of Amblyomma variegatum from the Caribbean.

Amblyomma variegatum (Fabricius), the tropical bont tick, is now widely distributed in the Caribbean. Eighteen islands countries are now or were recently infested with the tick. To stop the spread of this tick to other non-infested islands and to the mainland areas of South, Central and North America, a regional eradication program has been proposed and endorsed by the respective governments on each of the Amblyomma variegatum infested islands, including the French government and CARICOM member and associate member countries. The Food and Agriculture Organization of the United Nations (FAO) was requested by CARICOM, on behalf of member and associate member governments to: develop eradication proposals; assist CARICOM member countries to maintain existing Amblyomma tick control programs; advise and assist with the drafting of legislation required for implementation of an eradication program; assist in the identification of funds to implement the eradication program and, if funding was obtained, coordinate the eradication campaign against this tick on all infested islands. The current distribution of the tick and the status of the proposed eradication program in the Caribbean are discussed.

Animals↗
PubMed1991

Predators of the tick Amblyomma variegatum (Acari: Ixodidae) in Guadeloupe, French West Indies.

Some vertebrate species in Guadeloupe are predators of free or parasitic stages of Amblyomma variegatum (Fabricius). Among birds, 1.9% of the 421 identified animals found in the stomachs of grackles (Quiscalus lugubris), 1.6% of the 364 animals found in the stomachs of free-ranging chickens, and 0.3% of the 4642 animals found in the stomach of cattle egrets (Bubulcus ibis) were A. variegatum ticks. The most efficient predator of ticks was the tropical fire ant, Solenopsis geminata, which was observed to only attack engorged stages of ticks. An average of 8% of the 564 individual ticks or batch of ticks released on the ground, mainly in a grass environment, were attacked by this ant species. Mice (Mus musculus) and mongooses (Herpestes auropunctatus) feed on engorged nymphs and female ticks. None of the 15 strains of entomophagous nematodes, genera Steinernema and Heterorhabditis, experimentally put in contact with engorged larvae and nymphs were able to parasitize them. In the laboratory, the insects Megaselia scalaris (Diptera) and Tineola sp. (Lepidoptera) were occasionally found to feed on engorged and unfed ticks, respectively.

Animals↗
PubMed1991

Acaricide susceptibility of Amblyomma variegatum (Acari:Ixodidae) from Puerto Rico and Guadeloupe.

Base-line data on acaricide susceptibility of larvae and of larvae and nymphs of the tropical bont tick, Amblyomma variegatum (Fabricius), from Puerto Rico and Guadeloupe were collected on 14 and six compounds, respectively. Nymphs 7-8 weeks old from Puerto Rico and Guadeloupe, and larvae 3-4 weeks old from Guadeloupe, were exposed for 24 or 48 h to residues of acetone dilutions of technical-grade or commercial formulations of acaricides on disposable glass pipettes. Effectiveness of the acaricides in killing nymphs (LC50) from Guadeloupe and Puerto Rico ranged from 0.0001% for deltamethrin2 to 0.269% for malathion. For Puerto Rico, the susceptibility to toxaphene and amitraz, but not to dioxathion, increased with increasing age of nymphs. Nymphs from Guadeloupe were 9.5 times more susceptible to chlorpyrifos than nymphs from Puerto Rico. The susceptibility of larvae from Guadeloupe to acaricides tested ranged from LC50 0.000012% for deltamethrin to 0.0141% for ethion. There was no evidence of development of acaricide resistance in ticks from Guadeloupe or Puerto Rico.

Animals↗
PubMed1991

Control of ticks.

A number of different acaricides provide highly effective control of tick populations on dogs and cats. These acaricides are formulated as sprays, dips, dusts, or shampoos for use on the animal. Further protection of the animal from reinfestation with ticks can be achieved with the use of acaricide-impregnated flea and tick collars. Some of these acaricides are registered with the EPA for indoor and outdoor use as controls for free-living populations of ticks. Caution should be used when applying these materials. The label directions for the application of the acaricide and disposal of the acaricide containers should always be followed. Removal of underbrush and leaf litter, thinning trees, and frequently mowing grasses help reduce the number of free-living ticks. Any reduction in the amount of wildlife food sources and cover areas potentially decreases populations of ticks and thus reduces the potential of these ticks parasitizing a dog or cat. Application of an acaricide for area-wide control of free-living ticks in the spring, summer, and autumn also reduces the number of ticks. New approaches to area-wide control of ticks by use of acaricides that are focused on controlling the ticks attached to small mammal hosts are discussed. Although research has shown that reductions in tick numbers can be achieved using these methods, acceptance of these methods by regulatory agencies and the public requires further research.

Animals↗
PubMed1991

Control of Psoroptes cuniculi in captive white-tailed deer with ivermectin-treated corn.

Psoroptes cuniculi, the ear mite of domestic rabbits, was collected from captive white-tailed deer (Odocoileus virginianus). This is the first report of rabbit ear mite infestations in white-tailed deer in Oklahoma or Texas (USA). In addition to moderate infestations in their ears, two 4-yr-old bucks, two 3-yr-old does, and seven 4-yr-old does showed patchy areas of alopecia along the sides and brisket. Both bucks also had patchy areas of alopecia around the base of antlers. Ear mites were eradicated from all deer except from one doe by providing ivermectin-treated corn to the deer at a rate of 1,000 g (equivalent to 200 mcg/kg of ivermectin)/day/deer for several days. The ear mite infestation in the one doe was eradicated by intramuscularly injection with ivermectin at 400 mcg/kg. After treatment with the ivermectin and eradication of the mites, the alopecia improved and eventually was eliminated. The ivermectin-treated corn also controlled all internal nematode parasites in the deer.

Administration, Oral↗
PubMed1989

Evaluation of the eradication program for Amblyomma variegatum (Acari:Ixodidae) on Puerto Rico.

A cooperative effort between the United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, the Agricultural Research Service, and the Department of Agriculture, Commonwealth Government of Puerto Rico has been successful in eradicating Amblyomma variegatum (Fabricius) from the islands of Puerto Rico and Vieques (an island municipality of Puerto Rico). Application of acaricides to livestock and dogs at 14-day intervals for an 18-month period eliminated foci of tick infestation on 188 farms in four different locations without additional aerial or ground treatment. Reasons for the success and some of the costs associated with the eradication program on Puerto Rico are presented.

Animals↗
PubMed1989

Control of lone star ticks (Acari: Ixodidae) on Spanish goats and white-tailed deer with orally administered ivermectin.

Ivermectin administered orally to Spanish goats, Capra hircus (L.), or to white-tailed deer, Odocoileus virginianus (Zimmerman), was highly effective against lone star ticks, Amblyomma americanum (L.). For Spanish goats, daily oral doses of 20 micrograms/kg resulted in greater than or equal to 2 ppb ivermectin in the blood. This level was sufficient to cause greater than 95% reduction of estimated larvae from feeding ticks. A bioassay with horn flies, Haematobia irritans (L.), was developed to estimate oral intake of ivermectin. Probit analysis of dose-mortality data indicated that a 50% reduction in adult horn fly emergence can be expected when the manure from goats treated orally with ivermectin at 10, 20, 35, and 50 micrograms/kg/d was mixed with untreated cow manure at a rate of 0.345, 0.110, 0.100, and 0.092%, respectively. In studies with white-tailed deer, daily oral doses of 35 and 50 micrograms/kg/d provided 100% control of adult and about 90% control of nymphs that were placed on treated fawns. A single oral dose of 50 micrograms/kg gave greater than 90% control of adult and nymphal ticks attached to treated fawns at the time of drug administration and 70% control of ticks placed on treated deer three days thereafter. When ticks were placed on fawns treated with a single dose of ivermectin (50 micrograms/kg) the engorgement period was longer, ticks were lighter in weight, and females laid fewer eggs than ticks detaching from control fawns. A single oral dose of ivermectin at 20 micrograms/kg prevented about 60% of the adult and nymphal ticks attached at the time of drug administration from engorging, but did not affect other ticks placed on the animals after treatment.

Administration, Oral↗
PubMed1987

Use of Taylor's Power Law in examining the spatial distribution of free-living Boophilus microplus (Acari: Ixodidae) larvae in pastures in Puerto Rico.

Taylor's power law (y = amb) was used to analyze the spatial pattern of Boophilus microplus (Canestrini) larvae in tropical pastures. The index of aggregation b was 2.75 and showed that larvae were highly aggregated. The b-values differed significantly among certain pastures (LSD, P less than 0.05), and pasture type and use could have contributed to differences in b. The use of Taylor's power law to adjust for sampling inconsistencies that occur in tropical pastures where regimented sampling cannot always be followed is discussed.

Animals↗
PubMed1985

Survey for potential soft tick (Acari: Argasidae) vectors of African swine fever on the island of Hispaniola.

A survey of the occurrence of Ornithodoros ticks in animal burrows was conducted in Haiti and the Dominican Republic. Vacuum sampling techniques were used. Four of 8 sample sites in Haiti and 10 of 70 sample sites in the Dominican Republic were positive for O. puertoricensis Fox. Positive sample sites in Haiti were usually near swine. Sites in the Dominican Republic were in drier regions of the country and were not directly associated with previous swine locations. The determination that O. puertoricensis, a potential vector and reservoir of African swine fever (ASF), is present in this region may pose a serious problem for eradication of ASF from the island of Hispaniola.

African Swine Fever↗
PubMed1985

Ticks on livestock in St. Lucia.

Cattle, sheep, goats and horses were examined for ticks. Over 95% of Holstein cross-breeds, 28% of sheep (local mixed breeds) and 18% of goats (local mixed breeds) examined from 18 August to 4 September 1983 were infested with the southern cattle tick, Boophilus microplus Canestrini. About 90 and 17% of the horses examined were infested with the tropical horse tick, Anocentor nitens Neumann, and the tropical bont tick, Amblyomma variegatum Fabricius, respectively. The tropical bont tick was found infesting 10% of cattle in the Gros Islet area of St. Lucia. The tropical bont tick was also found associated with a severe skin disease, dermatophilosis, caused by the bacterium Dermatophilus congolensis, in 54% of the cattle infested by A. variegatum in the Gros Islet and Dauphin areas of St. Lucia.

Animals↗