Phenology of five tick species in the central Great Plains

The states of Kansas and Oklahoma, in the central Great Plains, lie at the western periphery of the geographic distributions of several tick species. As the focus of most research on ticks and tick-borne diseases has been on Lyme disease which commonly occurs in areas to the north and east, the ticks of this region have seen little research attention. Here, we report on the phenology and activity patterns shown by tick species observed at 10 sites across the two states and explore factors associated with abundance of all and life specific individuals of the dominant species. Ticks were collected in 2020-2022 using dragging, flagging and carbon-dioxide trapping techniques, designed to detect questing ticks. The dominant species was A. americanum (24098, 97%) followed by Dermacentor variabilis (370, 2%), D. albipictus (271, 1%), Ixodes scapularis (91, <1%) and A. maculatum (38, <1%). Amblyomma americanum, A. maculatum and D. variabilis were active in Spring and Summer, while D. albipictus and I. scapularis were active in Fall and Winter. Factors associated with numbers of individuals of A. americanum included day of year, habitat, and latitude. Similar associations were observed when abundance was examined by life-stage. Overall, the picture is one of broadly distributed tick species that shows seasonal limitations in the timing of their questing activity.

Multiple species of canine Rhipicephalus complex detected in Canada

Multiple species of brown dog ticks have been described in the United States and the Caribbean: Rhipicephalus sanguineus sensu stricto (s.s.), also referred to as temperate lineage; R. linnaei (=tropical lineage); and R. rutilus (=southeastern Europe lineage) However, Rhipicephalus spp. are rarely recovered from dogs in Canada. To identify canine Rhipicephalus spp. in Canada and determine the influence of travel history on infestation, ticks morphologically identified as brown dog ticks (n = 93) collected from dogs (n = 13) in British Columbia, Ontario, and Québec, Canada were submitted with information regarding each dog's geographic location and travel history. Nucleic acid was extracted from available individual ticks (n = 86) and PCR was used to amplify sequences of a 12S rRNA mitochondrial gene fragment. Sequences were compared to published reference sequences of known species and a phylogenetic tree constructed. Twenty-three ticks (26.7%) consistent with R. linnaei were identified on seven dogs, including dogs from British Columbia and Ontario, with a median infestation intensity of 2 ticks/dog (mean = 3.3 ticks/dog). Sixty-one ticks (70.9%) consistent with R. sanguineus s.s. were found on two dogs from Québec and Ontario (median = 30.5 ticks/dog; mean = 30.5 ticks/dog). One dog from Ontario was infested with R. rutilus (n = 2) (2.3%). Species could not be determined for ticks from three dogs from Ontario and Québec. Most infested dogs (10/13; 76.9%) had a recent (< 1 month) international travel history. These data confirm that multiple species of canine Rhipicephalus are occasionally found in Canada and suggest introduction following travel is likely responsible for these infestations. Further analysis will allow for greater understanding of the range and diversity of canine Rhipicephalus spp. in North America and may reveal risk factors for infestation.

Diagnosis of canine intestinal parasites: Improved detection of Dipylidium caninum infection through coproantigen testing

Intestinal parasites, including cestodes like Dipylidium caninum, are common in dogs in the United States of America (USA), but fecal flotation consistently, and, at times, dramatically, fails to identify many of these infections. To determine the extent to which including coproantigen testing for D. caninum would improve the identification of dogs infected with this cestode, we evaluated fecal samples from 877 dogs (589 pet and 288 from municipal shelters) from six USA states using zinc sulfate (specific gravity 1.24) fecal flotation with centrifugation along with coproantigen detection for Giardia sp., hookworms, ascarids, and Trichuris vulpis. For D. caninum, PCR of perianal swabs was included. Intestinal parasite infections were identified, using centrifugal fecal flotation or coproantigen, in 265 dogs (13.2 % pet, 64.9 % shelter). Dipylidium caninum infection was detected in 5.6 % of dogs with the combination of coproantigen and centrifugal fecal flotation, and 7.3 % of dogs when perianal swab results were included; prevalence varied by diagnostic method, population, and geographic region. In pet dogs, D. caninum infection was identified by fecal flotation (0), coproantigen (2.2 %), or perianal swabs (1.2 %). The same methods revealed infection in 0.3 %, 12.5 %, and 11.1 % of shelter dogs, respectively. Frequent use of praziquantel in shelter dogs (116/288; 40.3 %) may have reduced prevalence. Positive and negative agreement of D. caninum coproantigen with perianal swab PCR in pet dogs was 85.7 % and 98.8 %, respectively. Multiple logistic regression analysis accounting for region, population, and age found D. caninum infection to be more common in shelter dogs relative to pet (adjusted OR 4.91 [2.48, 10.24]) and in the Southcentral and Southeast regions relative to North (adjusted OR 9.59 [1.92, 174.13] and 17.69 [3.67, 318.09] respectively). Coproantigen testing also enhanced the detection of other intestinal parasites over fecal flotation alone, including Giardia sp. (14.7 % vs 3.3 %), hookworms (13.8 % vs 8.4 %), ascarids (2.9 % vs 2.2 %), and T. vulpis (2.9 % vs 1.4 %). Together, these data indicate that the coproantigen assay employed increases detection of D. caninum infections several fold, supporting the use of this test in clinical practice, and add to a growing body of research documenting enhanced diagnosis through implementation of multiple laboratory-based methods.

Expression of the nuclear transport protein importin ß-1 and its association with the neurokinin 3 receptor in the rat hypothalamus following acute hyperosmotic challenge

The tachykinin NK3 receptor (NK3R) is a G-protein coupled receptor that is activated, internalized, and trafficked to the nuclei of magnocellular neurons in the paraventricular nucleus of the hypothalamus (PVN) in response to acute hyperosmolarity. The lack of information on the nuclear import pathway raises concerns about the physiological role of nuclear NK3R. NK3R contains a nuclear localizing sequence (NLS) and this raises the possibility that importins are involved in transport of NK3R through the nuclear pore complex. The following experiments utilized: (1) co-immunoprecipitation to determine if NK3R is associated with importin ß-1 following activation in response to acute hyperosmolarity in vivo, and (2) immuno-neutralization of importin ß-1 in vitro to determine if nuclear transport of NK3R was blocked. Rats were given an i.v. injection of hypertonic saline (2 M) and 10 min after the infusion, the PVN was removed and homogenized. Importin ß-1 co-immunoprecipitated with the NK3R following treatment with 2 M NaCl, but not following isotonic saline treatment. Immuno-neutralization of importin ß-1 decreased the transport of NK3R into the nuclei in a time dependent fashion. The results indicate that in response to acute hyperosmotic challenge, NK3R associates with importin ß-1 which enables the nuclear transport of NK3R. This is the first in vivo study linking importin ß-1 and the nuclear transport of a G protein coupled receptor, the NK3R, in brain.