RESUMEN
An extended duration formulation of lambda-cyhalothrin (Icon CS) applied as either an ultra-low volume (ULV) or thermal fog spray from a new hand-held sprayer (Twin-Fog) or as a low-volume spray (LV) from a backpack mist blower against Aedes aegypti was evaluated in Costa Rica. Spray applications were made at the front door for 1 min or to each room for 15 sec for the ULV and LV, and thermal fog applications were made to houses in separate blocks for each treatment. The efficacy and duration of effectiveness of the spray was determined from sentinel caged mosquito mortality and mosquito collections from within houses using hand-held, battery-powered aspirators. Sentinel caged mosquito mortality in both open and sequestered locations was 97-100% for the ULV and thermal fog spray treatments, with control mortality less than 2%. Both ULV applications (front door and each room) provided 3 wk of significant control (P < 0.05) based on adult Ae. aegypti house collections.
Asunto(s)
Aedes , Insecticidas/administración & dosificación , Control de Mosquitos/métodos , Piretrinas/administración & dosificación , Aerosoles , Animales , Costa Rica , Urgencias Médicas , Vivienda , NitrilosRESUMEN
Neutralizing antibodies for dengue virus serotypes 1 and 2 and serotypes 2 and 3 were detected in 1998 in 12 of 53 (22.6%) and 3 of 10 (30.0%) bats sampled in Costa Rica and Ecuador, respectively. Dengue is a consistent health problem in the two Costa Rican communities in which bats were sampled. The high percentage of bats with neutralizing antibodies to dengue virus in these two Costa Rican communities suggests that bats may become infected with dengue virus. This appears to be the case in Costa Rica and Ecuador.
Asunto(s)
Anticuerpos Antivirales/sangre , Quirópteros/virología , Virus del Dengue/aislamiento & purificación , Dengue/veterinaria , Animales , Quirópteros/sangre , Costa Rica/epidemiología , Dengue/epidemiología , Dengue/virología , Virus del Dengue/inmunología , Ecuador/epidemiología , Pruebas de NeutralizaciónRESUMEN
The indirect fluorescent antibody test (IFAT) as used in Africa for detecting bovine trypanosomiasis was adapted for use in South America and evaluated. Antigen consisted of Trypanosoma vivax laden bovine blood fixed in a 60 : 40 : : acetone : methanol solution. The test detected initial titres of 1 : 50 and 1 : 100 at an average of 13.1 and 15.9 days post parasitaemia (PP). Maximum titres as high as 1 : 400 developed in eight calves at an average of 23.4 days PP. In another calf, 109 days PP were required. Efficacy in detecting sero-positive calves throughout the course of infection was 81.1 and 96.4 per cent at serum dilutions of 1 : 100 and 1 : 50 respectively. No false positive reactions occurred when sera from 36 haemoparasite-free calves were tested. Cross reactivity did not occur when sera from calves singularly infected with Trypanosoma theileri, T evansi, Anaplasma marginale, Babesia argentina, B bigemina and Eperythrozoon spp were similarly tested in the IFAT. No significant differences were found in IFAT results of surveys in which both conventional serum samples and sera eluted from dried blood samples on filter paper from the same calf were used.