Species composition and host preference of fleas (Insecta: Siphonaptera) on rodent and domestic animals in Tamil Nadu, India

The species composition and host preference of medically important fleas monitored in urban, semi-urban, and rural revealed 412(65%) and 222(35%) fleas. From urban and rural habitats 90 and 345 fleas were collected respectively. There was a significant difference between urban and rural habitats in flea abundance. From rodents and domestic animals 209 (33%) Xenopsylla cheopis, 203 (32%) X. astia and 222 (35%) Ctenocephalides felis fleas were recorded. Fleas were predominantly found on Rattus rattus 45(83.3%) and Canis familiaris 31(83.8%). Among the habitats, there was no significant difference in rodent flea positivity and dog/cat flea positivity.

Dogs' looking times and pupil dilation response reveal expectations about contact causality

Contact causality is one of the fundamental principles allowing us to make sense of our physical environment. From an early age, humans perceive spatio-temporally contiguous launching events as causal. Surprisingly little is known about causal perception in non-human animals, particularly outside the primate order. Violation-of-expectation paradigms in combination with eye-tracking and pupillometry have been used to study physical expectations in human infants. In the current study, we establish this approach for dogs ( Canis familiaris ). We presented dogs with realistic three-dimensional animations of launching events with contact (regular launching event) or without contact between the involved objects. In both conditions, the objects moved with the same timing and kinematic properties. The dogs tracked the object movements closely throughout the study but their pupils were larger in the no-contact condition and they looked longer at the object initiating the launch after the no-contact event compared to the contact event. We conclude that dogs have implicit expectations about contact causality.

Dogs (canis familiaris) underestimate the quantity of connected items: first demonstration of susceptibility to the connectedness illusion in non-human animals

In humans, numerical estimation is affected by perceptual biases, such as those originating from the spatial arrangement of elements. Different animal species can also make relative quantity judgements. This includes dogs, who have been proposed as a good model for comparative neuroscience. However, dogs do not show the same perceptual biases observed in humans. Thus, the exact perceptual/cognitive mechanisms underlying quantity estimations in dogs and their degree of similarity with humans are still a matter of debate. Here we explored whether dogs are susceptible to the connectedness illusion, an illusion based on the tendency to underestimate the quantity of interconnected items. Dogs were first trained to choose the larger of two food arrays. Then, they were presented with two arrays containing the same quantity of food, of which one had items interconnected by lines. Dogs significantly selected the array with unconnected items, suggesting that, like in humans, connectedness determines underestimation biases, possibly disrupting the perceptual system’s ability to segment the display into discrete objects. The similarity in dogs’ and humans’ susceptibility to the connectedness, but not to other numerical illusions, suggests that different mechanisms are involved in the estimation of quantity of stimuli with different characteristics.

Detección de Leishmania spp. (Trypanosomatidae) e identificación de ingestas sanguíneas en flebotomíneos de un nuevo foco de leishmaniasis en el Caribe colombiano.

Introducción: Aunque la leishmaniasis visceral (LV) es endémica en el Caribe colombiano, en los últimos años se ha observado un incremento en su área de distribución, con el registro de casos en nuevas localidades. Objetivos: En este estudio se caracterizaron los flebotomíneos, parásitos del género Leishmania y algunos vertebrados domésticos asociados al primer caso humano de LV en la vereda Toro, San Juan Nepomuceno, Bolívar, Colombia. Metodología: Los insectos fueron sometidos a extracción, amplificación y secuenciación de ADN para establecer si estaban infectados con Leishmania spp. e identificar sus ingestas sanguíneas. Adicionalmente, en los caninos se determinaron los títulos de anticuerpos anti-Leishmania mediante la técnica de inmunofluorescencia indirecta. Resultados: En total se recolectaron 2178 flebotomíneos, el 99,6% de los cuales fue identificado como Lutzomyia evansi. Los parásitos Leishmania infantum y Leishmania braziliensis fueron detectados en esta especie, con una frecuencia mínima de infección de 0,003% (3/1070) y 0,0009% (1/1070), respectivamente. El 16,73% de las hembras de Lu. evansi se encontraron alimentadas de Homo sapiens sapiens, el 16,32% de Capra hircus , el 12,45% de Sus scrofa domesticus, el 11,63 % de Bos indicus y el 9,79% de Canis familiaris. Uno de ocho caninos serológicamente evaluados fue positivo para leishmaniasis canina. Conclusión: El hallazgo en Lu. evansi de ingestas de sangre mixtas de humanos y caninos, evidencia el vínculo epidemiológico entre las Lutzomyia infectados con el parásito, los potenciales reservorios y la población humana, lo que explicaría la aparición del primer caso de LV en esta localidad del Caribe colombiano.

DOGS (CANIS FAMILIARIS) FROM YENISEYSK (17th-19th CENTURIES)

Статья посвящена описанию остеологической коллекции собак (103 экз.) из раскопок усадьбы Баландина XVIII-XIX вв. в г. Енисейске. Исследования показали, что это были собаки мелкого и среднего размера. Мелкая форма собак, по-видимому, происходит от каких-то привозных пород. Собаки средних размеров образовались от местных восточносибирских лаек. Продолжительность жизни собак небольшая -около 6 лет, что было обусловлено плохими условиями их содержания. The paper describes osteological selection of dogs (103 specimens) from the excavations of the Balandin's town mansion dating to the 18th-19th centuries in the city of Yeniseysk. According to the research, the dogs were small and of medium size. Small dogs were apparently brought into the city from some other places whereas the ancestors of the medium-size dogs were local East Siberian Laikas. These dogs did not live for a long time, in many cases, around six years, which was explained by poor animal welfare.