Ticks collected from humans, domestic animals, and wildlife in Yucatan, Mexico

Highlights

• Knowledge gaps in epidemiology of TBD impede strategies to mitigate ticks in Mexico.

• Known tick vectors of zoonotic pathogens infest animals and human in Mexico.

• 15 tick species were identified and most of them can act as a vector of pathogens.

• The tick species identified stresses the need for an integrated tick management.

Abstract

Domestic animals and wildlife play important roles as reservoirs of zoonotic pathogens that are transmitted to humans by ticks. Besides their role as vectors of several classes of microorganisms of veterinary and public health relevance, ticks also burden human and animal populations through their obligate blood-feeding habit. It is estimated that in Mexico there are around 100 tick species belonging to the Ixodidae and Argasidae families. Information is lacking on tick species that affect humans, domestic animals, and wildlife through their life cycle. This study was conducted to bridge that knowledge gap by inventorying tick species that infest humans, domestic animals and wildlife in the State of Yucatan, Mexico. Amblyomma ticks were observed as euryxenous vertebrate parasites because they were found parasitizing 17 animal species and human. Amblyomma mixtum was the most eryxenous species found in 11 different animal species and humans. Both A. mixtum and A. parvum were found parasitizing humans. Ixodes near affinis was the second most abundant species parasitizing six animal species (dogs, cats, horses, white-nosed coati, white-tail deer and black vulture) and was found widely across the State of Yucatan. Ixodid tick populations may increase in the State of Yucatan with time due to animal production intensification, an increasing wildlife population near rural communities because of natural habitat reduction and fragmentation. The diversity of ticks across host taxa documented here highlights the relevance of ecological information to understand tick–host dynamics. This knowledge is critical to inform public health and veterinary programs for the sustainable control of ticks and tick-borne diseases.

Introduction

Wildlife and domestic animals play important roles as reservoirs of zoonotic pathogens that are transmitted to humans by ticks (Morse, 1995). Besides their role as vectors of several classes of microorganisms of veterinary and public health relevance (Morse, 1995, Jongejan and Uilenberg, 2004), ticks also burden human and animal populations through their obligate blood-feeding habit (Ostfeld et al., 2006). Tick feeding causes irritation, skin inflammation, pruritus, self-wounding, stress, and allergic responses (Wall and Shearer, 2001). The world’s tick fauna comprises around 900 species, which are grouped under three families, Ixodidae, Argasidae and Nuttalliellidae (Guglielmone et al., 2010) and are distributed worldwide as parasites of terrestrial vertebrates (Nava et al., 2009). It is estimated that in Mexico there are 100 tick species belonging to the Ixodidae and Argasidae families (Pérez et al., 2014).

Several emerging and re-emerging tick-borne diseases have a wildlife species as their reservoir (Daszak et al., 2001, Pérez de León et al., 2014b). The development of improved strategies to mitigate the burden of zoonotic tick-borne diseases requires a better understanding of the biology and ecology of ticks, including the role of wildlife species as tick hosts and the epidemiology of tick-borne pathogens (Estrada-Peña et al., 2013, Ogden et al., 2013, Esteve-Gassent et al., 2014). Scientific progress is advancing our understanding of tick host specificity. Some tick species are host generalists and can feed on different vertebrate species depending on their availability and abundance (Wilson et al., 1984, Anderson, 2002), whereas other species may be more specific and use a narrow host range (Guglielmone et al., 2014). Many ticks parasitize domestic animals but few ticks feed exclusively on them as most tick species may also parasitize wild animals. Wild and domestic cycles are often complementary. Immature tick stages that parasitize wild and peridomestic animals can feed later as adults on domestic animals (Ruiz-Fons and Gilbert, 2010). However, it has been proposed that a more ecological view of tick-host associations at the local scale is required to better understand the implications of tick-host-pathogen interactions for the epidemiology, and control of zoonotic tick-borne diseases (McCoy et al., 2013, Ogden et al., 2013).

Studies examining the diversity of ticks parasitizing human, domestic animals, and wildlife in Mexico are scarce. It is important to describe the tick fauna parasitizing domestic animals and wildlife because several of these tick species can also parasitize humans and are reservoirs of zoonotic pathogens. Enhanced knowledge of tick spatial and temporal distributions can translate into improved local and regional tick control programs. Records of tick species infesting human, domestic animals, and wildlife in Yucatan, Mexico are reported here. The veterinary public health implications of these findings are discussed.