Conspecific hyperparasitism in the Hyalomma excavatum tick and considerations on the biological and epidemiological implications of this phenomenon

Conspecific hyperparasitism in two Ornithodoros species (Ixodida: Argasidae) endemic to Brazil, and interspecific hyperparasitism between Amblyomma sculptum and Rhipicephalus microplus (Ixodida: Ixodidae)

Hyperparasitism has been observed in soft and hard tick species around the world. In Brazil, the phenomenon of hyperparasitism has only been observed conspecifically in hard ticks of the genus Amblyomma. In the present study, we report unprecedented cases of hyperparasitism in soft and hard ticks. Conspecific hyperparasitism is reported for Ornithodoros fonsecai and Ornithodoros tabajara, while interspecific hyperparasitism is reported for Amblyomma sculptum on Rhipicephalus microplus.

First description of conspecific hyperparasitism in Amblyomma sculptum

The present study reports a case of conspecific hyperparasitism for Amblyomma sculptum. Two partially engorged females were collected from two naturally infested dairy cows and placed in a single petri dish to be transported to the laboratory, where they were held in a biological oxygen demand (BOD) incubator chamber under controlled conditions of 27 ± 1 °C and 85 ± 5% RH. After one day, it was observed that the smaller female (female 1) was attached to the dorsal surface of the larger female (female 2). The hypostome and chelicerae of the female 1 were entirely inserted into the cuticle of the female 2, characterizing tick attachment. Pictures were taken to illustrate the finding. After a few hours, the female 1 detached spontaneously and showed no visible signs of additional enlargement (engorgement). The females did not lay eggs and the survival period was not recorded. To our knowledge this is the first report of hyperparasitism for A. sculptum and the fourth for the genus Amblyomma.

The Potential Role of Migratory Birds in the Rapid Spread of Ticks and Tick-Borne Pathogens in the Changing Climatic and Environmental Conditions in Europe

This opinion piece highlights the role of migratory birds in the spread of ticks and their role in the circulation and dissemination of pathogens in Europe. Birds with different lifestyles, i.e., non-migrants residing in a specific area, or short-, medium-, and long-distance migrants, migrating within one or several distant geographical regions are carriers of a number of ticks and tick-borne pathogens. During seasonal migrations, birds that cover long distances over a short time and stay temporarily in different habitats can introduce tick and pathogen species in areas where they have never occurred. An increase in the geographical range of ticks as well as the global climate changes affecting the pathogens, vectors, and their hosts increase the incidence and the spread of emerging tick-borne diseases worldwide. Tick infestations of birds varied between regions depends on the rhythms of tick seasonal activity and the bird migration rhythms determined by for example, climatic and environmental factors. In areas north of latitude ca. 58°N, immature Ixodes ricinus ticks are collected from birds most frequently, whereas ticks from the Hyalomma marginatum group dominate in areas below 42°N. We concluded that the prognosis of hazards posed by tick-borne pathogens should take into account changes in the migration of birds, hosts of many epidemiologically important tick species.