Genetic structure and demographic history of new world screwworm across its current geographic range.

The phylogeographical history of the pest fly screwworm, Cochliomyia hominivorax (Coquerel), was studied using partial mitochondrial DNA sequences of the control region, Cytochrome c oxidase (CO) subunit I and CO subunit II from 361 individuals collected across its current geographic range. Analyses showed marked genetic differentiation on a macrogeographic scale. The genetic diversity in the species is structured into four main "regional groups," corresponding to Cuba, the Dominican Republic, and the North and South Amazon region. Results indicated that the distribution of screwworm genetic diversity was mainly shaped by historical events, i.e., colonization of Caribbean islands, vicariance in the Amazon region and population expansion. Demographic history analyses revealed that the population expansion started approximately 20-25,000 yr ago and recently increased exponentially. We hypothesized that the initial period of expansion was probably associated with environmental amelioration in the late Pleistocene and the exponential increase with resource availability in recent times. The population expansion is probably responsible for the low divergence and the lack of genetic and geographic correlation in the South Amazon region but did not erase the genetic structure pattern on a continental scale. The screwworm is one of the most damaging livestock pests in South and Central America, and the pattern of genetic variability distribution reported here suggests that the Caribbean area and the North and South Amazon regions could be considered as independent units for future pest control programs.

Serological prevalence of Babesia caballi and Theileria equi in horses of Lara State, Venezuela.

The main objective of this study was to demonstrate the occurrence of equine piroplasmosis (EP) in horses of Lara State, Venezuela, and to correlate it with the factors host's sex and age in order to know the epidemiology of this disease at the Venezuelan Centroccidental Region. Antibody levels to Babesia caballi and Theileria equi were assessed in 360 equine serum samples, collected from 9 municipalities of Lara State, using an ELISA technique with recombinant antigens and monoclonal antibodies (Mabs). Antibodies to B. caballi were found in 254 horses (70.6%), whereas 181 animals (50.3%) were detected as seropositives to T. equi. In addition, 128 samples (35.56%) were seropositives to both hemoparasites. There were no significant differences between the seropositivity to B. caballi and T. equi with the factors sex and age of the horses. These results show that Lara State is an enzootic area for equine piroplasmosis, and are a contribution to a partial knowledge of the dynamic of this disease in Venezuela.

Distribution and abundance of natural parasitoid (Hymenoptera: Pteromalidae) populations of house flies and stable flies (Diptera: Muscidae) at the University of Florida Dairy Research Unit.

From September 2001 through September 2002, house fly and stable fly pupae were collected weekly from three fly habitats at the University of Florida Research dairy in northcentral Florida and evaluated for parasitism. Varying parasitism percentages were observed throughout the study but they were not affected by temperature, precipitation or fly abundance. Of the 6,222 house fly pupae and 1,660 stable fly pupae that produced either a host fly or a parasitoid, 26.9% and 26.7% were parasitized, respectively. Ten parasitoid species were recovered, with the genus Spalangia accounting for 85.7% of the total; the most common parasitoids attacking house fly and stable fly pupae were Spalangia endius Walker (33.9% and 27.3%), S. cameroni Perkins (27.9% and 40.6%), and S. nigroaenea Curtis (21.0% and 24.8%), respectively. Other parasitoids included one specimen of S. erythromera Förster and four specimens of Phygadeuon fumator Gravenhörst (Ichneumonidae). The percentage parasitism of pupae collected from bunker silos was higher than that of pupae from calf pens and open pastures. Spalangia cameroni was consistently recovered through the entire year. Spalangia nigroaenea was predominant in July, August, and September. Spalangia endius was most active from October to May with a peak of relative abundance in January.

In vitro efficacy of amitraz and cypermethrin on Boophilus microplus from dairy farms in Lara State, Venezuela.

In Venezuela, the acaricides, amitraz and cypermethrin, are widely used to control tick infestations in cattle infested with Boophilus microplus. This work aims to determine the in vitro efficacy of amitraz and cypermethrin through the adult immersion test. A sample of 480 engorged females was collected from four dairy farms (180 ticks/farm) and divided in groups of 10 ticks averaging 220 mg/tick. Commercial preparation of amitraz and cypermethrin were used to prepare the working concentration of amitraz (52, 104, 208, 416 and 832 ppm), and cypermethrin (37.5, 75, 150, 300, 600 ppm). The control groups were submerged only in water. Ticks were placed in a glass lamina at 27 degrees C and 85% relative humidity (RH) and incubated for 18 days. The eggs masses were collected, weighed, separated in vials, and allowed to hatch at 85% RH and 27 degrees C for 21 days. Both the emerged larvae and eggs were quantified in each tube in order to determine the efficacy percentage and the resistance factor. The efficacy average to amitraz was 30.89%, 50.75%, 50.62%, 59.72%, and 60.53% at concentrations of 52, 104, 208, 416, and 832 ppm, respectively. The efficacy of cypermethrin was 14.3%, 11.82%, 17.25%, 20.23%, and 43.23% at concentrations of 37.5, 75, 150, 300, and 600 ppm, respectively. The amitraz resistance factor to each farm was 3.14, 1.19, 1.88, and 1.89, whereas with cypermethrin it was 8.89, 6.03, 7.12, and 18.45. Statistically significant differences between the effectiveness of different concentrations of amitraz or cypermethrin were not observed. Higher concentrations do not increase the efficacy of the products.

Distribution and abundance of natural parasitoid (Hymenoptera: Pteromalidae) populations of house flies and stable flies (Diptera: Muscidae) at the University of Florida Dairy Research Unit

From September 2001 through September 2002, house fly and stable fly pupae were collected weekly from three fly habitats at the University of Florida Research dairy in northcentral Florida and evaluated for parasitism. Varying parasitism percentages were observed throughout the study but they were not affected by temperature, precipitation or fly abundance. Of the 6,222 house fly pupae and 1,660 stable fly pupae that produced either a host fly or a parasitoid, 26.9 percent and 26.7 percent were parasitized, respectively. Ten parasitoid species were recovered, with the genus Spalangia accounting for 85.7 percent of the total; the most common parasitoids attacking house fly and stable fly pupae were Spalangia endius Walker (33.9 percent and 27.3 percent), S. cameroni Perkins (27.9 percent and 40.6 percent), and S. nigroaenea Curtis (21.0 percent and 24.8 percent), respectively. Other parasitoids included one specimen of S. erythromera Fõrster and four specimens of Phygadeuon fumator Gravenhõrst (Ichneumonidae). The percentage parasitism of pupae collected from bunker silos was higher than that of pupae from calf pens and open pastures. Spalangia cameroni was consistently recovered through the entire year. Spalangia nigroaenea was predominant in July, August, and September. Spalangia endius was most active from October to May with a peak of relative abundance in January.

[Prevalence of Anaplasma marginale and specific antibodies in new born calves]. / Prevalencia de Anaplasma marginale y anticuerpos específicos en becerros neonatos.

Anaplasma marginale is an intraerythrocytic rickettsia that affects the cattle and constitute a constraint for its production. The transplacental transmission of A. marginale could be of importance under field conditions, but until now no data is available to interpret its relevance in Venezuela. The goal of this work was to evaluate both the presence of A. marginale and the antibody response against the rickettsia in new born calves. Fourteen calves, one week old, were simultaneously bled for parasitological tests, packed cell volume measurement and to obtain sera for immunoenzymatic assays. All the animals showed parasitemia between seventeen and thirty days old. The antibody IgM and IgG response at this time was low. Probably, these calves acquired A. marginale infection through transplacental route and a very low level of immunity by the colostrum.

Especies de Amblyomma (acari: ixodidae) parasitando perros (canis familiaris) en áreas rurales de los estados Lara, Yaracuy, Carabobo y Falcón Venezuela / Species of Amblyomma (acari: ixodidae) parasitizing dogs (canis familiaris) from rural areas of Lara, Yaracuy, Carabobo y Falcón Venezuela

Un total de 50 caninos de áreas rurales de los estados Lara, Yaracuy, Carabobo y Falcón, Venezuela, fueron examinados visualmente y mediante palpación cutánea con el fin de detectar la presencia de garrapatas. Ninguno de los animales se encontró parasitado por Rhipicephalus sanguineus, la garrapata común del perro. Se colectaron 139 especimenes adultos del género Amblyomma Koch, 1844: 72 hembras y 65 machos de la especie Amblyomma ovale Koch, 1844, y dos hembras de la especie Amblyomma triste Koch, 1844. La identificación de los especimenes se realizó mediante observación en lupa estereoscópica y con la ayuda de claves taxonómicas. Los Estados donde se colectó el mayor número de ixódidos fueron Falcón con 52 especimenes y Lara con 49, representando 38 y 36%, respectivamente. A. ovale ha sido reportada como vector natural de Hepatozoon canis en áreas rurales. La especie A. triste fue colectada sólo en un canino del estado Yaracuy. Esta especie ha sido incriminada como el vector biológico de varios agentes rickettsiales patógenos, tanto para humanos como para animales domésticos y salvajes, por lo que se resalta la importancia del género Amblyomma en la transmisión de enfermedades zoonóticas.

Fifty dogs from the rural areas of Lara, Yaracuy, Carabobo and Falcón States of Venezuela were sampled through the visual and touch techniques in search of the presence of ticks. All the dogs were free of the brown dog tick Rhipicephalus sanguineus. A total of 139 adult ticks of the genus Amblyomma Koch, 1844 were collected: of them, 65 males and 72 females were identified as Amblyomma ovale Koch, 1844, whereas two females belonged to the species Amblyomma triste Koch, 1844. The observation through stereomicroscope, as well as the use of taxonomic keys, were employed in the identification of the collected specimens. Most of the ticks were collected in Falcón and Lara States, totalling 52 (38%) and 49 (36%), respectively. The species A. ovale has been reported as a natural vector of the protozoan Hepatozoon canis in rural areas. A. triste was collected only in one dog in Yaracuy State. This species has been incriminated as a biological vector of several rickettsial agents to the men and animals. The actual role of the genus Amblyomma as vector of zoonotic disease agents is highlighted.

Eficacia de diferentes acaricidas en el control de rhhipicephalus sangineus (acarina: ixodidae) / Efficacy of differets acaricides in the control of rhipicephalus sangiuneus (acaina: ixodicides)

Taleoginas de rhipicephalus sanguineus fueron sometidas al test de inmersión de adultos utilizando tres acaricidas comerciales en tres diluciones diferentes (0,5x; 1x y 2x) de acuerdo a las dosis recomendadaspor los fabricantes. el porcentaje de control parasitario varió entre 11,3 y 66,6 por ciento con el uso de coumafos, evidenciando un efecto dosis- respuesta y una falla terapéutica. La flumetrina y el amitraz exhibieron 100 por ciento de control de todas las diluciones probadas. El uso intensivo de amatraz contra otros ectoparásitos como sarcoptes scabie y demodex canis podría ser un factor importante en la selección de poblaciones de R. sanguineus resistentes a ese acaricida

Prevalencia de Anaplasma marginale y anticuerpos específicos en becerros neonatos / Prevalence of Anaplasma marginale and specific antibodies in new born calves

Anaplasma marginale is an intraerythrocytic rickettsia that affects the cattle and constitute a constraint for its production. The transplacental transmission of A. marginale could be of importance under field conditions, but until now no data is available to interpret its relevance in Venezuela. The goal of this work was to evaluate both the presence of A. marginale and the antibody response against the rickettsia in new born calves. Fourteen calves, one week old, were simultaneously bled for parasitological tests, packed cell volume measurement and to obtain sera for immunoenzymatic assays. All the animals showed parasitemia between seventeen and thirty days old. The antibody IgM and IgG response at this time was low. Probably, these calves acquired A. marginale infection through transplacental route and a very low level of immunity by the colostrum.

Evaluación de la anaplasmosis en becerros mestizos holstein naturalmente infectados y desafiados con aislados homólogos y heterólogos de anaplasma marginale / Evaluation of anaplasmosis in naturally infected crossbred-holstein calves challenged with homologous and heterologous isolates of anaplasma marginale

A pesar de la características endémica de la anaplasmosis en Venezuela, son pocos los estudios que refieren a la protección cruzada entre los diferentes aislados venezolanos de anaplasma marginale. El objetivo de este trabajo consistió en evaluar el desarrollo de la enfermedad de becerros mestizos Holstein infectados naturalmente con el aislado Lara y posteriormente desafiados con aislados homólogos y heterólogos de la rickettsia, en la búsqueda de protección cruzada. Para el logro de estos objetivos, se adquirieron becerros mestizos Holstein de un semana de nacidos en un finca del estado Lara, infectados de manera natural con A. marginale, y se dividieron en tres grupos de tres animales cada uno. A los seis meses de edad fueron reinfectados con un inóculo de 5 x 10 elevado a la 8 eritrocitos infectados con A. marginale del aislado homólogo Lara (grupo I), aislados heterólogos Táchira (grupo II) y Zulia (grupo III). Desde el comienzo de los experimentos se tomaron muestras de sangre completa para evaluar parasitemia y hematocrito y se evaluaron los signos clínicos. Los tres grupos fueron diferentes en relación al período pre-patente, porcentajes de disminución de hematocrito y niveles de parasistema después del desafío. Dos de los tres animales del grupo I resultaron protegidos contra el reto homólogo, al no manifestar características compatibles con la enfermedad, mientras que los animales de los grupos II y III presentaron evidencias clínicas de anaplasmosis. El grupo inoculado con el aislado de Zulia presentó mayor severidad clínica que el grupo desafiado con el aisldo Táchira

Grado de infección y mortalidad en la garrapata del caballo anocentor nitens (acari: ixodidae) naturalmente infectada por el protozoa babesia caballi (apicomplexa: babesiidae) / Infection degree and mortality in the horse tick anocentor nitens (acari: ixodidae) naturally infected by the protozoan babesia caballi (apicomplexa: babesiidae)

Con la finalidad de estudiar el porcentaje y grado de infección y la mortalidad de la garrapata Anocentor nitens infectada con Babesia caballi, fueron utilizadas 160 teleoginas de A. nitens provenientes de un equino con infección natural por B. caballi. Se conformaron 4 grupos de 40 teleoginas cada uno. Los grupos se evaluaron a los 5; 10; 15 y 20 días posteriores al desprendimiento del hospedador, contituyendo los grupos A, B, C, y D respectivamente. Se observó que un 49,62 por ciento de las teleoginas fueron positivas a esporoquinetos de B. caballi. El porcentaje de infección por esporoquinetos de B. caballi en la hemolinfa de las teleoginas fue de 67,5; 55; 55 y 20 por ciento para los grupos A, B, C y D respectivamente. Se evidenció una mortalidad del 85,1; 50; 59,1 y 25 por ciento para las teleoginas infectadas y de 7,7; 50; 77,8 y 65,6 por ciento para las teleoginas no infectadas de los grupos A, B, C y D respectivamente. El grado de infección en la hemolinfa disminuyó con el tiempo, lo cual puede estar relacionado con la migración de los esporoquinetos a otros órganos. La mortalidad en las teleoginas infectadas sugiere que A, nitens es susceptible al parasitismo por esporoquinetos de B. caballi, lo cual se traduce en un efecto adverso sobre la longevidad y el potencial reproductivo de esta especie

El benemérito cuerpo de bomberos voluntarios de Guatemala ante la protección civil y atención de desastres

El benemerito cuerpo de bomberos de voluntarios, fue creado el 16 de agosto de 1951 por iniciativa del Lic. Rodrígo González Allendes, Embajador de la República de Chile. Su propósito inicial la prevención, combate de incendios y rescate de victimas por diferentes emergencias. Para el 4 de febrero de 1976 se encontraban 33 estaciones de bomberos en funcionamiento con 1350 bomberos, 29 motobombas, 62 vehículos de rescate y ambulancias y 15 cisternas a nivel nacional con enexperiencia y desconocimiento del quehacer en caso de terremotos debidoa a la destrucción de edificaciones, corte de energía y comunicaciones, interrucción de vías de acceso, personas atrapadas e incendios. Actualmente la institución cuenta con 3649 bomberos, 98 estaciones, 61 motobombas, 201 vehículos de rescate y ambulancias, 84 cisternas, 2 vehículos especiales para rescate y 2 para transporte de personal (AU)