First Report of Haemaphysalis longicornis (Neumann) in Oklahoma, USA

Abstract

Haemaphysalis longicornis (Neumann), the Asian longhorned tick, is a species native to East Asia, but invasive to Australia, New Zealand, and most recently, the United States. It has spread rapidly across the eastern United States after being established in New Jersey in 2017. Aiding this rapid expansion is the ability of this tick to reproduce parthenogenically and feed on diverse host species. In cattle, this tick can cause heavy burdens and act as a vector for the pathogenic hemoprotozoan parasite Theileria orientalis, genotype Ikeda, creating economic losses that impact the cattle industry. Here, we report Asian longhorned ticks, collected from cattle, a dog, and pastures and morphologically identified at the Oklahoma Animal Disease Diagnostic Laboratory as H. longicornis before molecular confirmation through PCR amplification of the cox1 gene. Blood samples from infested cattle were collected and assessed molecularly for the presence of T. orientalis, with no pathogenic DNA detected. This report describes the first record of H. longicornis in Oklahoma and the farthest westward detection of this tick in the United States to date.

Keywords: Haemaphysalis longicornis; Oklahoma; Theileria orientalis; cattle; invasive species; range expansion.

Figure 1

Dorsal (A) view and ventral (B) view of an engorged female H. longicornis identified after collection from Oklahoma cattle. The ticks pictured measure approximately 5 mm in width by 8 mm in length. The characteristic lateral projection on palpal segment 2 (black arrowheads) and a dorsal spur on palpal segment 3 can be seen.

Figure 2

Multiple engorged female H. longicornis identified after collection from cattle residing in Oklahoma.

Figure 3

Neighbor-Joining phylogenetic tree depicting the relationship between cox1 sequences of haplotypes previously documented in the United States (H1, H2, H3) and ticks collected for the present report (shown in bold), out-grouped to Haemaphysalis bispinosa. Ticks from this study are designated with OK3–OK6.

Figure 4

Map of Oklahoma depicting counties with recently established populations of Asian longhorned ticks. Established is defined as the identification of at least six individual ticks, or at least two of three host-seeking life stages within one calendar year. Reported is defined as the identification of less than six individual ticks of a single life stage within one calendar year [31].