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Background: Estimates of tick abundance and distribution are used to determine the risk of tick-host contact. Tick surveys provide estimates of distributions and relative abundance for species that remain stationary and wait for passing hosts (i.e. questing), but measures of tick populations may be less reliable for species that actively move in search of a host, such as Amblyomma americanum, the lone star tick (LST). Risk estimates for contact with adult LST require knowledge of the tick's spatial and temporal activity. Understanding the movement and the temporal patterns of host-seeking behavior will enhance risk assessment for LST. Methods: Using CO2-baited traps over a 2-year period, we collected wild adult LST in Oklahoma. We used mark-recapture techniques to determine the distance ticks will travel, the proportion of the tick population that is detectable over time, and the relationship between tick abundance and the number of ticks detected in the field. Using video tracking software, we measured the distance traveled and activity time in the laboratory. Results: In 24 h, LST travel up to 9 (mean = 3.2, SD = 3.6) m in the field and 36 (mean = 70.4, SD = 81.0) m in the laboratory. Marked LST were detectable in the environment for up to 14 days after release. We found that the number of recaptured ticks significantly increased with the relative abundance of ticks released, and at a minimum abundance (N = 1 tick released) LST were detectable 33.3% of the time. Across all experiments, fewer than half of marked ticks were recovered and at most 28.4% of ticks were detected with CO2-baited traps at any given time. Conclusions: Our results show that LST actively move through the environment and pose a risk for host contact at distances of tens of meters. Ticks are detectable for several weeks, but only a fraction of them are detectable at any time. Larger numbers of ticks are detected as their population size increases, but even at very low numbers, LST are recovered with CO2 baiting. These spatial and temporal aspects of LST behavior should be considered when building predictive risk models of LST-host contact. [ABSTRACT FROM AUTHOR]

BackgroundCytauxzoonosis is a disease of felids in North America caused by the tick-transmitted apicomplexan parasite Cytauxzoon felis. Cytauxzoonosis is particularly virulent for domestic cats, but no vaccine currently exists. The parasite cannot be cultivated in vitro, presenting a significant limitation for vaccine development.MethodsRecent sequencing of the C. felis genome has identified over 4300 putative protein-encoding genes. From this pool we constructed a protein microarray containing 673 putative C. felis proteins. This microarray was probed with sera from C. felis-infected and naïve cats to identify differentially reactive antigens which were incorporated into two expression library vaccines, one polyvalent and one monovalent. We assessed the efficacy of these vaccines to prevent of infection and/or disease in a tick-challenge model.ResultsProbing of the protein microarray resulted in identification of 30 differentially reactive C. felis antigens that were incorporated into the two expression library vaccines. However, expression library immunization failed to prevent infection or disease in cats challenged with C. felis.ConclusionsProtein microarray facilitated high-throughput identification of novel antigens, substantially increasing the pool of characterized C. felis antigens. These antigens should be considered for development of C. felis vaccines, diagnostics, and therapeutics.

Case series summary: This case series describes six cases involving seven cats naturally infected with Cytauxzoon felis in Indiana, USA. Medical records were retrospectively reviewed and all available information on signalment, history, clinical and diagnostic findings, treatment, outcome and pathology was reported. Cats infected with C felis were domestic shorthairs, were aged between 2 and 9 years and all but one of the cats were male. The seven infected cats originated from five counties in southwestern Indiana. Six of seven cats were found to have acute cytauxzoonosis based on clinical signs, gross pathologic lesions, observation of C felis in tissues and/or detection of C felis DNA. One cat was identified as a subclinical survivor cat with no known clinical history of cytauxzoonosis. Relevance and novel information: The reported cases are the first confirmed reports of acute and chronic cytauxzoonosis in cats from Indiana and document an expansion in the range of C felis. Veterinary practitioners in Indiana should consider infection with C felis as a differential diagnosis for cats that present with fever, inappetence, lethargy, depression, dehydration, dyspnea, hemolytic crisis, anorexia or icterus. Administration of approved acaricides to cats currently offers the best protection and control against C felis infection. [ABSTRACT FROM AUTHOR]

Cytauxzoonosis is a fatal tick-borne disease in domestic cats caused by infection with the apicomplexan Cytauxzoon felis. Bobcats are the natural wild-vertebrate reservoirs for C. felis, and infections are typically subclinical and chronic in this species. The present study was done to determine the prevalence and geographic distribution of C. felis infection in wild bobcats from Oklahoma and the occurrence in northwestern Texas. Tongue samples from 360 bobcats were collected from 53 counties in Oklahoma and 13 samples from three counties in Texas. For DNA extracted from each tongue sample, a probe-based droplet digital PCR assay was performed targeting the C. felis mitochondrial gene cytochrome c oxidase subunit III (cox3). Prevalence of C. felis infection was calculated for each county sampled, and data from individual counties were combined according to geographic regions and compared using chi-square tests. Overall prevalence of C. felis in bobcats from Oklahoma was 80.0% (95% confidence interval [CI], 75.6–83.8). The prevalence of infection was >90% for bobcats from central, northeastern, south-central, and southeastern regions of Oklahoma, but <68% for bobcats from northwestern and southwestern regions. Bobcats from central counties in Oklahoma were 25.693 times more likely to be infected with C. felis compared to all other bobcats sampled from the state. Higher prevalence estimates of C. felis in bobcats appeared to be in counties where known tick vectors are most common. Occurrence of C. felis in bobcats from northwestern Texas was 30.8% (95% CI, 12.4%–58.0%) based on 13 samples. Results of this study support the utilization of bobcats as sentinel animals to identify geographic areas with risk of C. felis infection to domestic cats. [ABSTRACT FROM AUTHOR]

Objectives The objectives of the present study were to determine the duration of infestation by Amblyomma americanum necessary for transmission of Cytauxzoon felis to domestic cats and to determine if ingestion of C felis-infected A americanum by cats is a route of transmission. Methods Forty-nine cats were assigned to one of seven groups, with seven cats per group. Cats were infested with A americanum adults, acquisition fed as nymphs on a cytauxzoonosis survivor cat, for 12 h (group 1), 18 h (group 2), 24 h (group 3), 36 h (group 4), 48 h (group 5) and to repletion (group 7; control). Cats in group 6 were fed C felis-infected ticks. Thumb counts were performed at the end of the duration of infestation for groups 1–5 and at 48 h for the control group. For group 6, 50 live C felis-infected adult A americanum were mixed with food and fed to each of the cats. Transmission of C felis was determined by examining blood of cats by DNA extraction followed by PCR. Results Of 50 ticks placed on each cat (groups 1–5 and 7), the arithmetic mean attachment ± SEM ranged from 46.9 ± 1.9 in group 3 to 49.3 ± 0.3 in group 1. In group 6, the average number ± SEM of ticks ingested was 46.5 ± 2.3. One cat in group 5 that had been infested for 48 h became infected with C felis. None of the cats in group 6 (ingestion) became infected with C felis. Six of 7 (85.7%) cats in group 7, the control group, became infected with C felis. Conclusions and relevance Our results indicate that transmission of C felis to domestic cats can happen as quickly as >36 h but ⩽48 h of exposure to A americanum infected with C felis and that ingestion of C felis-infected A americanum is not a likely route of transmission. [ABSTRACT FROM AUTHOR]

Objectives To determine whether pretreating diagnostic samples with heat increases the detection of Dirofilaria immitis antigen in adult cats, we evaluated feline serum and plasma samples collected in heartworm-endemic areas of the southern United States. Methods Commercial microtiter well assays for detection of D immitis antigen were used to evaluate serum or plasma samples from 385 shelter and free-roaming cats from the southcentral and southeastern United States before and after heat treatment; commercial antibody tests were performed on a subset of samples. Results Prior to sample heat treatment, 1/220 (0.5%) shelter cats and 4/165 (2.4%) free-roaming cats had detectable D immitis antigen. After heat pretreatment, the detection rate increased to 13/220 (5.9%) and 13/165 (7.9%), respectively. Antibody reactive to D immitis was significantly more common (P <0.001) in the serum of cats that were antigen positive after heat treatment (10/13; 76.9%) than serum from cats that remained antigen negative after heat treatment (22/163; 13.5%). Conclusions and relevance Heat pretreatment of feline samples increased antigen detection by commercial assays for D immitis and improved overall concordance of antigen and antibody test results in antigen-positive samples in this population. Although further work to investigate the specificity of D immitis antigen assays when using pre-treated samples is warranted, this approach may be useful in the diagnosis of heartworm infection in individual cats and may increase the accuracy of surveys based on antigen detection. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the efficacy of combined treatment with ivermectin and fenbendazole (IVM-FBZ) for treating captive olive baboons (Papio anubis) infected with Strongyloides fülleborni and Trichuris trichiura, 2 common nematode parasites of these NHP. Infected baboons were treated for a total of 9 wk with ivermectin (400 μg/kg IM twice weekly) and fenbendazole (50 mg/kg PO once daily for 3 d; 3 rounds of treatment, 21 d apart). Five baboons naturally infected with both S. fülleborni and T. trichiura (n = 4) or S. fülleborni alone (n = 1) received the combination therapy; an additional baboon infected with both parasites served as a nontreated control. The efficacy of IVM-FBZ was measured as the reduction in fecal egg counts of S. fülleborni and T. trichiura as determined by quantitative fecal flotation examination after treatment of baboons with IVM-FBZ. All baboons treated with IVM-FBZ stopped shedding S. fülleborni and T. trichiura eggs by 8 d after treatment and remained negative for at least 161 d. The nontreated control baboon shed S. fülleborni and T. trichiura eggs throughout the study period. Our results indicate that the IVM-FBZ regimen was efficacious for treating olive baboons infected with S. fülleborni and T. trichiura.

Case summary Cytauxzoonosis is a tick-borne disease of cats, and Oklahoma (OK), USA, is considered an enzootic state. To determine the prevalence of Cytauxzoon felis , blood was collected from free-roaming cats, as they are frequently exposed to tick vectors. Our objective was to determine the prevalence of C felis infection in free-roaming cats in north-central Oklahoma and central Iowa (IA). Infection with C felis was determined using DNA extracted from blood and PCR amplification. Blood was collected from 380 free-roaming cats between January and April in 2014 in OK. DNA from C felis was detected in 3/380 (0.8%; 95% confidential interval [CI] 0.22-2.3%). In IA, 292 blood samples were collected between 2012 and 2014. No C felis -infected cats were detected (0; 95% CI 0-0%). Relevance and novel information The prevalence of C felis (0.8%) in north-central OK reported herein was lower than the previously reported 3.4% in domestic cats in OK. Our study supports that the prevalence in a given enzootic area can vary by location and from the pool of cats sampled. None of 291 (0%) cats were infected with C felis in central IA. To date, only one case of cytauxzoonosis in a domestic cat has been reported in IA. It is important to monitor cats for C felis infections in northern US states, as geographic distribution of Amblyomma americanum expands northward. As free-roaming cats have more contact with the tick vectors of C felis , this population allows us to monitor the expansion of C felis distribution., Competing Interests: Conflict of interest: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.