Fascioliasis in Llama, Lama glama, in Andean Endemic Areas: Experimental Transmission Capacity by the High Altitude Snail Vector Galba truncatula and Epidemiological Analysis of Its Reservoir Role

South American camelids are definitive hosts of Fasciola hepatica. However, their capacity to participate in the transmission and epidemiology of fascioliasis has never been appropriately studied. Therefore, an F. hepatica isolate from Argentine llama is for the first time analyzed using Galba truncatula lymnaeids from Bolivia. Experimental follow-up studies included egg embryogenesis, miracidial infection of lymnaeid snails, intramolluscan larval development, cercarial production, chronobiology of cercarial shedding, vector survival to infection, and metacercarial infectivity of mammal host. Shorter prepatent and patent periods were leading to markedly lower cercarial production, shorter cercarial shedding, and a higher negative impact on snail survival. The usually low liver fluke prevalences and intensities and low daily fecal outputs indicate that llamas do not substantially contribute to fascioliasis transmission. The defecating behavior in dung piles far from freshwater collections prevents lymnaeid infection by eggs shed by this camelid. All results suggest the reservoir role of the llama to be negligible and, therefore, no priority within control measures in endemic areas. However, llamas may play a disease-spreading role if used as pack animals in rural areas. In the Northern Bolivian Altiplano human hyperendemic area, neither llamas nor alpacas should be considered for control measures within a One Health action.EEA SaltaFil: Mas-Coma, Santiago. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Cafrune Wierna, Marí­a Mercedes. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Funatsu, Ilra Renata. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina.Fil: Angles, Rene. Universidad Mayor de San Andrés. Facultad de Medicina. Cátedra de Parasitología; BoliviaFil: Buchon, Paola. Universidad Mayor de San Andrés. Instituto de Ecología. Unidad de Limnología; BoliviaFil: Fantozzi, Maria Cecilia. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Artigas, Patricio. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Valero, Maria Adela. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Bargues, Maria Dolores. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; Españ

El Uso de Insecticidas para el Control de Haematobia Irritans (L.) (Diptera: Muscidae) en la Argentina

Se efectuaron 806 encuestas en 11 provincias para conocer los insecticidas ylas técnicas de aplicación que se utilizan para el control de la Haematobia irritansen los sistemas productivos de bovinos para leche, carne, cría o ciclo completo enla Argentina. Se observó un uso generalizado de piretroides aplicados en formatópica aunque con ciertas particularidades manifestadas en tres agrupamientos:el primero para Corrientes (ganadería de cría mayoritariamente en la zona infestadacon la garrapata común del vacuno) con propensión a la ausencia de tratamientos;un segundo agrupamiento que caracteriza al resto de la ganadería de cría también en el área infestada con garrapatas, donde es más común el uso depiretroides asociado con avermectinas pero también el uso de avermectinas comoúnico insecticida, con tendencia hacia la aplicación tópica combinada con inyeccióny el empleo de baños de inmersión. El tercer agrupamiento abarca a la regiónlibre de garrapatas con sistemas productivos para leche, invernada y ciclocompleto en la llanura pampeana y Entre Ríos; donde es relativamente común eluso de piretroides asociado con organo-fosforados y el uso de organo-fosforadoscomo único insecticida; la aplicación tópica de biocidas combinado con aspersióno caravanas junto con el uso único de caravanas o aspersión es más notorio eneste agrupamiento.Fil: Suarez, Víctor Humberto. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Castellino, Marta Elena. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Aguirre, Héctor David. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Alcaraz, Eliana Sabrina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Cetrá, B.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Fader, O. W.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Luciani, C. A.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Medus, P. D.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; ArgentinaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias; Argentin

First mitochondrial and nuclear DNA sequences of Lamanema chavezi (Nematoda: Molineidae): Novel findings to improve its identification in feces from South American camelids

Lamanema chavezi (Family Molineidae) is a parasitic nematode of South American camelids (SACs). A few studies have reported this parasite in SACs, mainly in domestic camelid species (llama and alpaca). Parasite identification by means of copro-parasitological methods is non-invasive and allows performing epidemiological studies. However, egg misidentification and difficulty to culture third-stage larvae do not allow identifying nematodes to species level. In contrast, molecular tools allow identifying eggs of gastrointestinal nematodes more accurately. However, the little genomic information available in databases for some species prevents an accurate diagnosis. In the present work, L. chavezi females present in feces of llamas from northwestern Argentina were molecularly characterized to obtain genomic information and improve parasitological diagnosis of L. chavezi-like eggs present in guanaco feces from southeastern Argentina. An 833-bp fragment of nuclear ribosomal DNA (rDNA) and a 434-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene from both L. chavezi females and eggs were amplified and sequenced. Comparison between sequences from females and eggs showed 99–99.6% identity to rDNA and 99.5–96.1% to the cox1 gene fragments, confirming egg morphological assignment. A higher divergence between sequences was observed in the cox1 fragment, with a maximum variation of 3.9%. The examination of eggs found in guanaco feces from southeastern Argentina and their specific molecular identification represent the first record for this host in Argentine Patagonia and contribute to improving the diagnosis of gastrointestinal nematodes in SACs, mainly in wild camelids.Fil: Petrigh, Romina Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Investigación Animal del Chaco Semiárido; ArgentinaFil: Fugassa, Martín Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; Argentin

Experimental infestation of llamas (Lama glama) with Boophilus microplus (Acari: Ixodidae)

Two llamas (Lama glama) were infested with approximately 20,000 Boophilus microplus larvae each and maintained under controlled conditions to collect the detached adult ticks. A total of 72 engorged and semi-engorged females were recovered with a mean weight of 163.0 ± 70.6 mg. Sixty-three (87.5%) of these ticks oviposited and 60 (95.2%) of the egg masses produced larvae. Six of the heaviest females laid 18,838 eggs from which 16,545 (87.8%) hatched. These results show that llamas are able to maintain a population of B. microplus under experimental conditions. Further studies are required to determine the role of llamas as alternative hosts for B. microplus under field conditions.Fil: Aguirre, Héctor David. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Guglielmone, Alberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentin

Amblyomma tigrinum (Acari: Ixodidae): New data on hosts and biology of immature stages and on DNA composition

Biological data of immature stages of Amblyomma tigrinum were obtained from larvae and nymphs both fed on rats and rabbits. Data from nymphs recovered from a wild rodent (Galea musteloides) are also reported. Additional results in DNA composition of males moulted from nymphs fed on laboratory and wild hosts are presented. The ticks were maintained in darkness at 27 1 8C and 83?86% RH. The mean recovery rates were 49.1% and 43.6% with a moulting success of 96.2% and 90.8% in larvae fed on rats and rabbits, respectively. The engorgement weights were almost identical in larvae recovered from both hosts. The mean recovery rates of nymphs were 37.3% and 69.9% in specimens fed on rats and rabbits, respectively. The moulting success was 94.5%, 100% and 98.1% in nymphs fed on rats, rabbits and G. musteloides, respectively. Nymphs from all hosts moulting to females were significantly heavier (P < 0.01) than those moulting to males despite their range of engorgement weight showed overlap. A higher proportion (61.5%) of nymphs from all hosts moulted to females. Present results suggest that members of Rodentia and Lagomorpha are suitable hosts for the immature stages of A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.Amblyomma tigrinum were obtained from larvae and nymphs both fed on rats and rabbits. Data from nymphs recovered from a wild rodent (Galea musteloides) are also reported. Additional results in DNA composition of males moulted from nymphs fed on laboratory and wild hosts are presented. The ticks were maintained in darkness at 27 1 8C and 83?86% RH. The mean recovery rates were 49.1% and 43.6% with a moulting success of 96.2% and 90.8% in larvae fed on rats and rabbits, respectively. The engorgement weights were almost identical in larvae recovered from both hosts. The mean recovery rates of nymphs were 37.3% and 69.9% in specimens fed on rats and rabbits, respectively. The moulting success was 94.5%, 100% and 98.1% in nymphs fed on rats, rabbits and G. musteloides, respectively. Nymphs from all hosts moulting to females were significantly heavier (P < 0.01) than those moulting to males despite their range of engorgement weight showed overlap. A higher proportion (61.5%) of nymphs from all hosts moulted to females. Present results suggest that members of Rodentia and Lagomorpha are suitable hosts for the immature stages of A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.Galea musteloides) are also reported. Additional results in DNA composition of males moulted from nymphs fed on laboratory and wild hosts are presented. The ticks were maintained in darkness at 27 1 8C and 83?86% RH. The mean recovery rates were 49.1% and 43.6% with a moulting success of 96.2% and 90.8% in larvae fed on rats and rabbits, respectively. The engorgement weights were almost identical in larvae recovered from both hosts. The mean recovery rates of nymphs were 37.3% and 69.9% in specimens fed on rats and rabbits, respectively. The moulting success was 94.5%, 100% and 98.1% in nymphs fed on rats, rabbits and G. musteloides, respectively. Nymphs from all hosts moulting to females were significantly heavier (P < 0.01) than those moulting to males despite their range of engorgement weight showed overlap. A higher proportion (61.5%) of nymphs from all hosts moulted to females. Present results suggest that members of Rodentia and Lagomorpha are suitable hosts for the immature stages of A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum. 1 8C and 83?86% RH. The mean recovery rates were 49.1% and 43.6% with a moulting success of 96.2% and 90.8% in larvae fed on rats and rabbits, respectively. The engorgement weights were almost identical in larvae recovered from both hosts. The mean recovery rates of nymphs were 37.3% and 69.9% in specimens fed on rats and rabbits, respectively. The moulting success was 94.5%, 100% and 98.1% in nymphs fed on rats, rabbits and G. musteloides, respectively. Nymphs from all hosts moulting to females were significantly heavier (P < 0.01) than those moulting to males despite their range of engorgement weight showed overlap. A higher proportion (61.5%) of nymphs from all hosts moulted to females. Present results suggest that members of Rodentia and Lagomorpha are suitable hosts for the immature stages of A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.G. musteloides, respectively. Nymphs from all hosts moulting to females were significantly heavier (P < 0.01) than those moulting to males despite their range of engorgement weight showed overlap. A higher proportion (61.5%) of nymphs from all hosts moulted to females. Present results suggest that members of Rodentia and Lagomorpha are suitable hosts for the immature stages of A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.P < 0.01) than those moulting to males despite their range of engorgement weight showed overlap. A higher proportion (61.5%) of nymphs from all hosts moulted to females. Present results suggest that members of Rodentia and Lagomorpha are suitable hosts for the immature stages of A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.A. tigrinum, contrasting with previous results from Brazilian colonies of this tick. The DNA sequence from ticks fed on G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.G. musteloides showed 99.7% identity with that from ticks fed on rabbits and also with the DNA sequence already available (GenBank AY498562) for A. tigrinum.AY498562) for A. tigrinum.Fil: Aguirre, Héctor David. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Guglielmone, Alberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentin

Eprinomectin pour-on for control of Boophilus microplus (Canestrini) ticks (Acari: Ixodidae) on cattle

The efficacy of a commercial pour-on formulation of eprinomectin, a macrocyclic lactone, against experimental infestations of Boophilus microplus (Canestrini) ticks was evaluated in two trials involving 27 Bos taurus calves. The first trial was designed to evaluate the effects of a single treatment at a dose of 0.5 mg/kg of body weight against standard size B. microplus females (4.5–8.0 mm long). A significant reduction in tick numbers (P 93% was obtained from Day 2 to Day 28 after treatment in calves treated twice at 0.5 mg/kg, and to the end of the trial (Day 35) in calves treated once with 1 mg/kg. The 1 mg/kg treatment provided >98% residual efficacy for at least 7 days. During the first part of the second trial the efficacy of eprinomectin resulted from a dramatic adverse effect on engorgement weight and fertility of female ticks, with 100% control on Day 5 (dosage of 1 mg/kg) and on Days 6 and 7 (two doses of 0.5 mg/kg). Following Day 7, most of the effect was due to reduction in the number of standard size female ticks.Fil: Aguirre, Héctor David. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Gaido, Analía Beatriz. No especifíca;Fil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Castelli, Maria Eugenia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Mangold, Atilio Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

Taxonomic key to nymphs of the genus Amblyomma (Acari: Ixodidae) in Argentina, with description and redescription of the nymphal stage of four Amblyomma species

In the present study, we provide morphological descriptions of the nymph of Amblyomma parvitarsum, A. tonelliae, and redescriptions of A. argentinae and A. sculptum. A taxonomic key, with relevant morphological characters illustrated by scanning electron micrographs, is provided for nymphs of the 24 species of the genus Amblyomma occurring in Argentina. Species included are A. argentinae, A. aureolatum, A. auricularium, A. boeroi, A. brasiliense, A. calcaratum, A. coelebs, A. dissimile, A. dubitatum, A. incisum, A. longirostre, A. neumanni, A. nodosum, A. ovale, A. parvitarsum, A. parvum, A. pseudoconcolor, A. pseudoparvum, A. rotundatum, A. sculptum, A. tigrinum, A. tonelliae, A. triste and A. varium. Principal morphological characters used for discrimination among species are presence/absence of auriculae, cornua and festoons with tubercles, size and shape of spurs of coxa I, margin and punctations of scutum, shape of basis capituli and length of cervical grooves. The geographical distribution of each tick species included in this work is presented and the importance of an accurate determination to species level of the Amblyomma nymphs to make epidemiological inferences is also discussed.Fil: Martins, Thiago F.. Universidade de Sao Paulo; BrasilFil: Labruna, Marcelo B.. Universidade de Sao Paulo; BrasilFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta - Jujuy; ArgentinaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

Normatización de la técnica PCR-RFLP para el estudio de resistencia al albendazol en parásitos de importancia veterinaria en el Valle de Lerma, Salta

La producción ganadera es afectada por nematodos gastrointestinales que dañan la mucosa del abomaso e intestinos, afectando la absorción de nutrientes y la ganancia de peso. El albendazol (ABZ), se une a la beta-tubulina evitando la polimerización de dímeros de tubulina en microtúbulos conduciendo a la interrupción de funciones celulares y muerte de la larva. La resistencia a los antiparasitarios se define como la habilidad de una población de parásitos, para tolerar dosis de tóxicos que serían letales para la mayoría de individuos en una población normal (susceptible) de la misma especie. La resistencia de Haemonchus contortus hacia el ABZ está dada por una mutación puntual en el gen de la beta-tubulina, TTC a TAC en el codón 200 del gen. Dicha mutación introduce un sitio de restricción para la enzima TaaI. El objetivo del presente trabajo fue normatizar la técnica de PCR-RFLP para la determinación del genotipo del gen de la b-tubulina isotipo I de H. contortus asociado a la resistencia al ABZ en la región del Valle de Lerma, Salta. Se recolectaron larvas de H. contortus con sospecha de resistencia a ABZ provenientes de la localidad de Campo Quijano proporcionadas por el departamento de Sanidad Animal, INTA Salta. La extracción de ADN se realizó con fenol cloroformo. La técnica PCR-RFLP fue usada para detectar el SNP. Un pool de larvas (>25 larvas) de H. contortus fue utilizado para la estandarización de la técnica PCR RFLP, con el fin de luego realizarla sobre larvas individuales (LI) y determinar la frecuencia genotípica. Se Detectó el genotipo de resistencia al ABZ en el pool larvas, no así en LI, encontrándose dificultades para la extracción de ADN (28% PCR positivas en LI). Los resultados confirman que en la región está presente el gen de resistencia al ABZ en H. contortus. La PCR-RFLP es una herramienta valiosa para la detección de resistencia al ABZ en helmintos y podría ser implementada en los programas de control.Fil: Diaz, Juan Pablo. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Fleitas, Pedro Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Olmos, Leandro Hipolito. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Aguirre, Daniel H.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Nasser, Julio Rubén. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaFil: Cimino, Rubén Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta. Sede Regional Orán. Instituto de Investigación de Enfermedades Tropicales; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Escuela de Biología. Cátedra de Química Biológica; ArgentinaVIII Congreso de ParasitologíaCorrientesArgentinaAsociación Parasitológica Argentin

Susceptibility to two pyrethroids in Boophilus microplus (Acari: Ixodidae) populations of northwest Argentina Preliminary results

Cattle are treated 6-12 times yearly to control Boophilus microplus ticks in the east zone of the Argentinean infested region, while 1-4 treatments are applied for tick control in the west zone. In the 1970s resistance to organo-phosphate acaricides was found in the east zone, but not in the west zone. However, a shift to synthetic pyrethroids (SP) was made through all infested regions. Currently, indications of resistance to SP in the east zone, but not in the west zone, are provoking to a switch to formamidine acaricides. During 1998 a total of 147 B. microplus engorged females were collected from 20 beef cattle ranches from the west zone of the Argentinean infested region. Individual progenies of these ticks were tested ('larval packet test') with cypermethrin and deltamethrin, and their LC 50 and LC 90 were compared to those estimated for the Milagro susceptible strain. No evidence of resistance to these SP was found. Due to sampling restraints the results are presented as preliminary. Nevertheless, a shift away from use of SP for control of B. microplus in the west zone appears to be unjustified and should be independent of the resistance circumstances observed in the east zone of the Argentinean tick infested region. (C) 2000 Elsevier Science B.V.Fil: Aguirre, D. H.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Viñabal, A. E.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Salatin, A. O.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Cafrune, Maria Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Volpogni, M.M.. Universidad Nacional del Litoral. Facultad de Agronomia y Veterinaria; ArgentinaFil: Mangold, Atilio Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Guglielmone, Alberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Santa Fe. Estación Experimental Agropecuaria Rafaela; Argentin