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Camponotus is a hyper-diverse ant genus that is associated with the obligate endosymbiont Blochmannia, and often also with Wolbachia, but morphological studies on the location of these bacteria in the queen's ovaries during oogenesis remain limited. In the present study, we used the Neotropical weaver ant Camponotus textor to characterize the ovary using histology (HE) techniques, and to document the location of Blochmannia and Wolbachia during oogenesis through fluorescence in situ hybridization (FISH). This is the first morphological report of these two bacteria in the same host with polytrophic meroistic ovaries and reveals that Blochmannia is found inside late-stage oocytes and Wolbachia is associated with the nuclei of the nurse cells. Our results provide insights into the developmental sequence of when these bacteria reach the egg, with Blochmannia establishing itself in the egg first, and Wolbachia only reaching the egg shortly before completing egg development. Studies such as this provide understanding about the mechanisms and timing of the establishment of these endosymbionts in the host.

In the present work features of tick-bite lesions were evaluated in capybaras naturally infested with Amblyomma cajennense and Amblyomma dubitatum ticks. Gross appearance of tick bite site was characterized by a mild swelling and erythema. Microscopic examination revealed the cement cone, a tube-like homogenous eosinophilic mass penetrating deep into the dermis. This structure was surrounded in the dermis by a cellular infiltrate and free eosinophilic granules and was associated to edema of variable intensity. Necrosis was a common feature deep in the dermis particularly at the far end of the eosinophilic tube. Hyperplasia, cellular edema and occasionally necrosis of keratinocytes could be seen at both sides of the ruptured epidermis. Cellular infiltrate was constituted overwhelmingly by polymorphonuclear leukocytes with eosinophilic granules. In capybaras cells with such features can be either eosinophils or heterophils (pseudoeosinophils), the latter being the equivalent of neutrophils of other mammals. Ultrastructural analysis of the cellular infiltrate revealed the predominance of heterophils over eosinophils. Mononuclear cells and mast cells and, in lesser numbers, basophils were also seen at skin attachment sites. The presence of heterophils in the reaction of capybaras against Amblyomma ticks is an outstanding feature but its role in the reaction to the tick is not known. It is however speculated that capybara heterophils might be associated with a more permissive environment for tick feeding and pathogen transmission as already shown for the equivalent cell type, the neutrophil, in the reaction of the dog against the Rhipicephalus sanguineus tick.

A study of ticks associated with wild animals was carried out from September 1996 to April 1998 at the Fazenda Alegria (21,000 ha), in the Nhecolândia Pantanal, State of Mato Grosso do Sul, Brazil, a sunken plain bordering the upper Paraguay river, located 19 × 08′S; 56 × 46′W. A total of 81 wild animals (13 species, 6 orders) were captured with the aid of nets, and ticks were found on 63 (78%). Tick species identified included Boophilus microplus (Canestrini), Amblyomma cajennense (F.), A. parvum (Aragão), A. pseudoconcolor (Aragão), A. scalpturatum (Neumann), A. nodosum (Neumann), A. ovale (Koch), and A. tigrinum (Koch). Dragging from grasslands (campos) yielded negative results compared to the high concentration of ticks, mainly nymphs, that were collected from leaves in the forests (capão). Predominance of immature instars (Amblyomma genera) was observed in the end of winter (August‐September). Ticks were associated mainly with coatis, deer (Mazama gouazoubira) and anteater, and these animals may play a role in the epidemiology of tick‐transmitted pathogens in the Pantanal if one considers their co‐existence with local domestic animals.

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Ticks are ectoparasites of medical and veterinary importance, which transmit many infectious agents, causing significant damage to the hosts. The "dog tick" Rhipicephalus sanguineus is responsible for transmitting several pathogens to dogs, motivating researchers to investigate efficient and sustainable control methods. Currently, chemical acaricides currently in use target the central nervous system (synganglion), which is responsible for controlling all the systemic functions of the ticks. Here, the neurotoxic potential of deltamethrin on the synganglion of unfed R. sanguineus female ticks was investigated. The results showed that the synganglion of the females belonging to the control group presented intact morphological characteristics; however, the ones from the treatment group (exposed to 1.5, 3.12 and 6.25 ppm of deltamethrin) displayed alterations, which were increasingly intense as the concentration increased. Observed alterations were mainly in the cortex region and in the neuropile, indicating that the deltamethrin is neurotoxic.

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