Abstract Vector-borne diseases (VBDs) continue to pose a challenge to the efforts of public health agencies by increasing their impact on the health of the affected communities. The common feature of VBDs is that the only way of preventing them is by avoid ing the contact between vectors and humans. There are no vaccines, and they will not be available shortly as tools for prevention and control in Argentina. Although dengue outbreaks attracted the attention of mass media from 2009, other VBDs have been affecting public health in Argentina for many decades, as Chagas disease and leishmaniasis. Over these, and others that could potentially settle in the national territory (West Nile, Lyme, etc.), there are repeated mass media claims and political declarations justifying their increase because of climate changes. The argument asserts that the “tropicalization” of the climate in temperate regions promotes the instal lation of VBDs in areas previously unfavorable for them. Although much evidence exists showing that the climate is changing, there is very little evidence that the climate is the main factor promoting the increase of VBDs. In this article, the influence of the so-called climate change on the situation of disease vectors in Argentina (with emphasis on triatomines) and vector control activities implemented by governmental public health agencies are discussed.

Resumen Las enfermedades transmitidas por vectores (ETVs) continúan siendo un desafío para los esfuerzos de agencias de salud pública, ya que mantienen o están aumentando su impacto sobre la salud de las comunidades afectadas. La característica común de las ETVs es que la única manera de prevenir exito samente nuevas infecciones es evitar el contacto entre vectores y humanos. No existen vacunas y no existirán en un futuro previsible para las principales ETVs que afectan la salud pública en Argentina. Aunque las epide mias de dengue desde 2009 atrajeron la atención mediática, otras ETVs, tales como Chagas o leishmaniasis, afectan la salud pública en Argentina desde hace décadas. Sobre ellas, y otras que potencialmente podrían instalarse en el territorio nacional (West Nile, Lyme, etc) hay repetidas referencias mediáticas que explican su recrudecimiento por el cambio climático. El argumento se basa en que la “tropicalización” del clima en regiones templadas promueve la instalación de ETVs en áreas previamente no favorables para ellas. Aunque existen muchas evidencias de que el clima está cambiando, son pocas las evidencias de que sea el clima el principal factor que promueve el recrudecimiento de las ETVs en Argentina. En este artículo, se discute la situación de los vectores de enfermedades en Argentina (con énfasis en triatominos), su vinculación con el llamado cambio climático y las actividades de control de vectores implementados por agencias gubernamentales de salud pública.

This is a description of experimental field studies that evaluated the efficacy of Telenomus fariai as a biological control agent of Triatoma infestans, the main vector of Trypanosoma cruzi (the aetiological agent of Chagas disease) in the Southern Cone countries of Latin America. The objective of this note is to report the inefficacy of T fariai to regulate the population abundance of T infestans under field conditions in a narrative way, as the original data have long been lost and unpublished because "negative” results were not published at the time (1980s). The aim is to correct that selective reporting and inform interested colleagues about efforts made on an idea that was (and probably still is) very appealing at the time the work was made.

Esta es una descripción de estudios experimentales hechos en campo para evaluar la eficacia de Telenomus fariai como agente de control biológico de Triatoma infestans, el principal vector de Trypanosoma cruzi (agente etiológico de la enfermedad de Chagas) en países del Cono Sur de Sud América. El objetivo de esta nota es informar la ineficacia de T fariai para regular la abundancia poblacional de T infestans bajo condiciones de campo en forma narrativa, ya que desafortunadamente los datos originales se perdieron hace tiempo, no publicados debido a que los resultados "negativos” no eran usualmente publicados al momento de los estudios (década de 1980). La finalidad de la nota es corregir el reporte selectivo e informar a colegas interesados acerca de los esfuerzos hechos sobre una idea que era (y probablemente aún es) muy atractiva al momento de realizar el trabajo.

Triatoma infestans is the main vector of the parasite that causes the Chagas disease in South America. It is known that T. infestans has different reproductive and development patterns depending on whether they feed on birds or mammals. Using the head of adult insects as an estimator of the specimen development, we attempt to determine if there are any differences in the sexual size dimorphism associated with the availability of the food resource in T. infestansof natural habitats in the Llanos Riojanos region (Argentina). The nutritional status resulted higher in chicken coops and, in both habitats, it was higher for females in relation to males. The centroid size was larger in females than in males from chicken coops, but not in the specimens from goat corrals. Centroid sizes revealed smaller medians in goat insects in comparison to those coming from chicken coops. Sexual size dimorphism occurs associated with differences in the nutritional status only for triatomines from chicken coops in natural habitats. The heads shape was not infuenced by the nutritional status. The sexual morphophysiological differences found in T. infestanshelp us understand aspects of the behavior of the species in diverse environments and its implications in the vectorial transmission o f Trypanosoma cruzi.

Triatoma infestanses el principal vector del parásito que causa la enfermedad de Chagas en Sudamérica. Se sabe que T. infestanstiene diferentes patrones reproductivos y de desarrollo dependiendo de si se alimentan de aves o mamíferos. Utilizando la cabeza de insectos adultos como estimador del desarrollo, se intenta determinar si existen diferencias en el dimorfsmo de tamaño sexual asociado con la disponibilidad del recurso alimenticio e n T. infestans de hábitats naturales en la región de Llanos Riojanos (Argentina). El estado nutricional fue mayor en gallineros y, en ambos hábitats, fue mayor para las hembras en relación con los machos. El tamaño centroide fue mayor en las hembras que en los machos de gallineros, pero no en los especímenes de corrales de cabras. Los tamaños centroide revelaron medianas más pequeñas en insectos de cabra en comparación con los procedentes de gallineros. El dimorfsmo sexual del tamaño se asocia con diferencias en el estado nutricional solo para triatominos de gallineros de habitats naturales. La conformación de las cabezas no se vio infuenciada por el estado nutricional. Las diferencias morfofsiológicas encontradas en T. infestans ayudan a comprender aspectos del comportamiento de la especie en diversos ambientes y sus implicaciones en la transmisión vectorial d eTrypanosoma cruzi.

Triatoma infestans is the most important vector of Chagas disease in Argentina. We report for the first time the presence of T. infestans (Klug) (Hemiptera: Reduviidae) associated with burrowing parrot nests Cyanoliseus patagonus (Psittasiformes: Psittacidae) built on abandoned adobe houses. The possible implications of this finding are discussed, for entomological surveillance of the vector.

Triatoma infestans es el vector más importante de la enfermedad de Chagas de la Argentina. Se cita por primera vez la presencia de T. infestans (Klug) (Hemiptera: Reduviidae) asociado a nidos de loro barranquero Cyanoliseus patagonus (Psittasiformes: Psittacidae) construidos en viviendas de adobe abandonadas. Se discuten las posibles implicancias de este hallazgo para la vigilancia entomológica del vector.

O presente trabalho teve como objetivo avaliar a influência da temperatura e umidade relativa sobre o ciclo biológico, mortalidade e fecundidade de Triatoma rubrovaria. Formaram-se quatro coortes, cada uma de 60 ovos recentemente colocados. As coortes foram divididas em dois grupos: O grupo condições controlada foi mantido em estufa com temperatura e umidade constantes, e o grupo temperatura ambiental foi mantido em condições variáveis de temperatura e umidade. O tempo de incubação dos ovos foi de 15.6 condições controlada e de 19.1 dias temperatura ambiental. O período de desenvolvimento de ovo a adulto foi de dez meses em condições controlada e 4 meses mais extenso em temperatura ambiental. A taxa de eclosão foi 99.1% em condições controlada e 98.3% em temperatura ambiental. A fecundidade foi 817.6 condições controlada e 837.1 temperatura ambiental. O percentual de mortalidade ninfal foi 52.6% no grupo condições controlada e 51.8% no grupo temperatura ambiental. As variações de temperatura e umidade relativa exercem influência no ciclo biológico e em alguns padrões reprodutivos desta espécie, mas não em sua mortalidade.

The aim of this study was to evaluate the temperature and relative humidity influence in the life cycle, mortality and fecundity patterns of Triatoma rubrovaria. Four cohorts with 60 recently laid eggs each were conformed. The cohorts were divided into two groups. In the controlled conditions group insects were maintained in a dark climatic chamber under constant temperature and humidity, whereas triatomines of the ambiental temperature group were maintained at room temperature. Average incubation time was 15.6 days in the controlled conditions group and 19.1 days in the ambiental temperature. In group controlled conditions the time from egg to adult development lasted 10 months while group ambiental temperature took four months longer. Egg eclosion rate was 99.1% and 98.3% in controlled conditions and ambiental temperature, respectively. Total nymphal mortality in controlled conditions was 52.6% whereas in ambiental temperature was 51.8%. Mean number of eggs/female was 817.6 controlled conditions and 837.1 ambiental temperature. Fluctuating temperature and humidity promoted changes in the life cycle duration and in the reproductive performance of this species, although not in the species mortality.

Aedes albifasciatus is an important common mosquito in Central Argentina. Its a confirmed vector of the Western Equine Encephalitis and is responsible for loss of milk production in dairy cattle during peak populations. This paper reports the flight activity pattern of Ae. albifasciatus for different seasons, in the southern coast of the Mar Chiquita Lake (Central Argentina). Data were collected by sampling two sites between 1992 and 1993 with CDC traps and human-bait captures. Adult mosquito population density, estimated by CDC trapping and human-bait, were highly correlated. However, when compared to other species, the proportion of Ae. albifasciatus was higher in human-bait collections. Adult female populations were active only when temperature were higher than 6§C. Two daily biting peaks were observed (dusk and dawn) during the spring, summer and autumn, and only one peak during winter (around 15:00 pm). Adult abundance was significantly correlated (R²= 0.71; p<0.01) with temperature and illumination.

Aedes albifasciatus is a flood water mosquito ocurring in the southern countries of South America. It is a competent vector of the Western Equine Encephalitis (WEE) and causes important losses on milk and beef production in central Argentina. Field work was carried out from December 1990 to March 1993, on a monthly basis during the dry season and biweekly during the rainy season. Larvae were collected using the 'dipping' technique and females with CDC traps baited with CO2. Field collected larvae were used to build laboratory cohorts, from which basic population parameters were estimated. Eggs survived up to six months on dry soil, although there was a linear decrease of viability with time. At 23ºC, larval development time was around nine days, and all adults emerged within one week. The estimation of larval development in the laboratory seems to be very near the development on the field, as larvae have been collected on average eight days after a rainfall. Egg to adult survival was 83%, with the highest mortality on fourth larval instar (6%). In the laboratory studies, sex proportion among the adults was 1:1, females lived longer than males (median 13 and five days, respectively), and adult survival pattern showed a constant number of individuals dying per unit time. Field collected females layed an average of 84 eggs per batch, and completing up to five gonotrophic cycles, suggesting an estimated survival of up to 35-50 days.

Because of the relative epidemiological significance of Triatoma sordida, T. guasayana and T. patagonica, and the need to resolve doubts about their taxonomic validity, we report here a detailed taxonomic comparison of the three species using multivariate analysis of morphometric measures combined with comparisons of their genitalia and antennal structures. From the 17 metric variables studied, the length of the second segment of the rostrum and the anteocular length provided a discrimination function able to separate without error T. sordida from T. guasayana and T. patagonica. The multivariate discriminant functions classified T. guasayana and T. patagonica with an error of 2.44%. Comparison of the male genitalia of T. guasayana and T. sordida showed that there are minor differences in the articulatory apparatus, the median process of the pygophore, the phallosome support and the vesica, with bigger differences in the endosomal process and the phallosome. However, the already described male genitalia of T. patagonica is very similar to that of T. sordida. Analysis of antennal structure by scanning electron microscope showed that sensilla distribution around the pedicel is slightly different in the three species and sensilla density is highest in T. sordida and lowest in T. patagonica. The study showed that the three species form a closely related group. The results confirm the earlier classification of sordida and guasayana as separate species, but they raise some doubts about the taxonomic status of T. patagonica.