Frequent Exposure to Many Hunting Dogs Significantly Increases Tick Exposure

Biodiversity, prevalence, and risk factors associated with tick infestation of Indigenous Nigerian breed of hunting dogs in Kwara State, Nigeria

Ticks are hematophagous arthropods that cause paralysis, toxicosis, and more importantly, they harbor and transmit different pathogens affecting humans and animals. This study was aimed to investigate the species composition, richness, diversity indices, prevalence, and risk factors associated with tick infestation of indigenous Nigerian breed of hunting dogs in Kwara State, Nigeria. The study was conducted on 240 hunting dogs from six local government areas in Kwara State. The dogs were subjected to integumentary examinations and the collected ticks were collected in 70% ethanol and transported to the Laboratory where they were morphologically identified using standard entomological keys. Of the 240 hunting dogs sampled, 157 were infested with ticks representing 65.4% with a 95% CI of 59.2-71.2. A total of 1206 ticks were collected belonging to Amblyomma variegatum, Haemaphysalis leachi, Hyalomma rufipes, Rhipicephalus decoloratus, Rhipicephalus microplus, and Rhipicephalus linnaei (Audouin, 1826), with Rhipicephalus linnaei being the most prevalent. The biodiversity and species richness indices, the prevalence of the infestation patterns, cumulative counts and mean load, species of ticks based on their developmental stages and sexes, as well as the degree of tick infestation were determined. Age was the only risk index significantly associated with the infestation of ticks among hunting dogs in the study. These findings underscore the importance of implementing tick control programs for hunting dogs, which may serve as reservoirs of ticks and tick-borne pathogens for domestic and pet dogs and humans.

The epidemiology of tick infestation in dog breeds in the UK

OBJECTIVES

The purpose of this study is to report the prevalence and risk factors for tick infestation in dogs in the UK based on anonymised electronic patient records.

MATERIALS AND METHODS

Clinical records of dogs under veterinary care in 2016 at clinics participating in the VetCompass Programme were followed over a 5-year period to identify cases of tick infestation. Risk factor analysis used multivariable logistic regression modelling.

RESULTS

The study included 905,553 dogs. From a random sample, 1903 tick infestation cases were identified. The estimated 5-year (2014 to 2018) period prevalence was 2.03% (95% confidence interval: 2.00 to 2.06). Sixteen breeds showed increased odds compared with non-designer-crossbreed dogs. Breeds with the highest odds included Cairn terrier (odds ratio 2.86, 95% confidence interval 1.64 to 4.98), standard poodle (odds ratio 2.80, 95% confidence interval 1.25 to 6.29) and Goldendoodle (odds ratio 2.63, 95% confidence interval 1.17 to 5.91). Six breeds showed reduced odds, with lowest odds shown by Staffordshire bull terrier (odds ratio 0.35, 95% confidence interval 0.25 to 0.50), Rottweiler (odds ratio 0.35, 95% confidence interval 0.15 to 0.85) and Chihuahua (odds ratio 0.38, 95% confidence interval 0.26 to 0.55). Males had 1.24 (95% confidence interval 1.13 to 1.36) times the odds of females. Compared with non-designer-crossbred dogs, designer-crossbreed dogs had increased odds (odds ratio 1.81, 95% confidence interval 1.52 to 2.15). Compared with breeds with short coats, breeds with medium length coats (odds ratio 2.20, 95% confidence interval 1.96 to 2.48) showed increased odds. Breeds with V-shaped drop and pendulous ear carriage had higher odds compared with breeds with erect ear carriage.

CLINICAL SIGNIFICANCE

These findings provide an evidence base for veterinary professionals to raise awareness of tick infestation as a preventable disorder in dogs in the UK and to support more effective prevention and therapeutic protocols based on targeted approaches.

Detection of Endosymbiont Candidatus Midichloria mitochondrii and Tickborne Pathogens in Humans Exposed to Tick Bites, Italy

During 2021, we collected blood and serum samples from 135 persons exposed to tick bites in southern Italy. We serologically and molecularly screened for zoonotic tickborne pathogens and only molecularly screened for Candidatus Midichloria mitochondrii. Overall, 62 (45.9%) persons tested positive for tickborne pathogens. Coxiella burnetii was detected most frequently (27.4%), along with Rickettsia spp. (21.5%) and Borrelia spp. (10.4%). We detected Candidatus M. mitochondrii DNA in 46 (34.1%) participants who had statistically significant associations to tickborne pathogens (p<0.0001). Phylogenetic analysis of Candidatus M. mitochondrii sequences revealed 5 clades and 8 human sequence types that correlated with vertebrates, Ixodes spp. ticks, and countries in Europe. These data demonstrated a high circulation of tickborne pathogens and Candidatus M. mitochondrii DNA in persons participating in outdoor activities in southern Italy. Our study shows how coordinated surveillance among patients, clinicians, and veterinarians could inform a One Health approach for monitoring and controlling the circulation of tickborne pathogens.

Vector-borne pathogens of zoonotic concern in hunting dogs of southern Italy

Dogs are commonly exposed to vector-borne pathogens (VBPs), yet few data are available on hunting dogs, which are often at high risk of infection due to their involvement in field activities. To investigate the occurrence of VBPs and evaluate the relative performance of different diagnostic tools, blood and serum samples were collected from hunting dogs (n = 1,433) in rural areas of southern Italy. All samples were tested by Knott's technique for filarioids, serologically (SNAP® 4Dx® Plus) for Anaplasma spp., Borrelia burgdorferi sensu lato, Dirofilaria immitis and Ehrlichia spp. and molecularly (qPCR) for all except B. burgdorferi of the above pathogens plus Babesia spp. and Leishmania infantum. Logistic regression was run to evaluate the statistical associations between the risk of VBP infection and independent variables (such as geographic area of provenience, age class and sex) and K-Cohen formula for assessing the concordance among diagnostic tests. Overall, out of 321 dogs (22.4%) positive to at least one VBP, 28 (1.9%) were infected by filarial species at the Knott's technique. In particular, Acanthocheilonema reconditum was the most prevalent (1.6%), followed by D. immitis (0.2%) and Dirofilaria repens (0.1%). One hundred forty (9.8%) and 231 (16.1%) dogs scored positive to VBPs by serological and molecular methods, respectively. The most prevalent pathogens detected were Ehrlichia spp. (7.3%) with SNAP® 4Dx® Plus, and A. reconditum (7.7%) by qPCR. Statistics revealed a significant association (p < 0.001) between A. reconditum infestation and both Ehrlichia spp. seropositivity and geographical origin of dogs. An agreement of 99.9%, 94.0% and 95.7% for Knott - SNAP® 4Dx® Plus, Knott - qPCR and SNAP® 4Dx® Plus - qPCR for D. immitis was found, respectively. Data demonstrate a high prevalence of VBPs in hunting dogs, indicating that this group of animals is largely exposed to several arthropod vector species and suggesting the transmission risk of pathogens to humans in rural areas of southern Italy. A multi-diagnostic approach and a deeper cooperation among healthcare and stakeholders are required to prevent VBP infections to animals and humans.

Occupational Lyme Disease: A Systematic Review and Meta-Analysis

Lyme disease (LD) can have significant consequences for the health of workers. The frequency of infection can be estimated by using prevalence and incidence data on antibodies against Borrelia Burgdoferi (BB). A systematic search of studies published in English between 2002 and 2021 and a meta-analysis were conducted in PubMed/Medline, Web of Science, Scopus, and Google Scholar databases. Out of a total of 1125 studies retrieved, 35 articles were included in the systematic review. Overall, in these studies, outdoor workers showed a 20.5% BB seroprevalence rate. Meta-analysis, performed on 15 studies (3932 subjects), revealed a significantly increased risk in outdoor activities (OR 1.93 95%CI 1.15–3.23), with medium-level heterogeneity (I² = 69.2%), and non-significant publication bias. The estimated OR in forestry and agricultural workers was 2.36 (CI95% 1.28; 4.34) in comparison with the controls, while a non-significant increase in risk (OR = 1.05, CI95% 0.28; 3.88) was found in the remaining categories of workers (veterinarians, animal breeders, soldiers). The estimated pooled risk was significantly higher in the studies published until 2010 (OR 3.03 95%CI 1.39–6.61), while in more recent studies the odds became non-significant (OR 1.08 95% CI 0.63–1.85). The promotion of awareness campaigns targeting outdoor workers in endemic areas, and the implementation of local programs aimed at controlling range expansion of vectors, are key strategies for protecting workers.

Use of Cervid Serosurveys to Monitor Eastern Equine Encephalitis Virus Activity in Northern New England, United States, 2009-2017

Vertebrate surveillance for eastern equine encephalitis virus (EEEV) activity usually focuses on three types of vertebrates: horses, passerine birds, and sentinel chicken flocks. However, there is a variety of wild vertebrates that are exposed to EEEV infections and can be used to track EEEV activity. In 2009, we initiated a pilot study in northern New England, United States, to evaluate the effectiveness of using wild cervids (free-ranging white-tailed deer and moose) as spatial sentinels for EEEV activity. In Maine, New Hampshire, and Vermont during 2009-2017, we collected blood samples from hunter-harvested cervids at tagging stations and obtained harvest location information from hunters. U.S. Centers for Disease Control and Prevention processed the samples for EEEV antibodies using plaque reduction neutralization tests (PRNTs). We detected EEEV antibodies in 6 to 17% of cervid samples in the different states and mapped cervid EEEV seropositivity in northern New England. EEEV antibody-positive cervids were the first detections of EEEV activity in the state of Vermont, in northern Maine, and northern New Hampshire. Our key result was the detection of the antibodies in areas far outside the extent of documented wild bird, mosquito, human case, or veterinary case reports of EEEV activity in Maine, New Hampshire, and Vermont. These findings showed that cervid (deer and moose) serosurveys can be used to characterize the geographic extent of EEEV activity, especially in areas with low EEEV activity or with little or no EEEV surveillance. Cervid EEEV serosurveys can be a useful tool for mapping EEEV activity in areas of North America in addition to northern New England.

The Impact of Deforestation, Urbanization, and Changing Land Use Patterns on the Ecology of Mosquito and Tick-Borne Diseases in Central America

Central America is a unique geographical region that connects North and South America, enclosed by the Caribbean Sea to the East, and the Pacific Ocean to the West. This region, encompassing Belize, Costa Rica, Guatemala, El Salvador, Honduras, Panama, and Nicaragua, is highly vulnerable to the emergence or resurgence of mosquito-borne and tick-borne diseases due to a combination of key ecological and socioeconomic determinants acting together, often in a synergistic fashion. Of particular interest are the effects of land use changes, such as deforestation-driven urbanization and forest degradation, on the incidence and prevalence of these diseases, which are not well understood. In recent years, parts of Central America have experienced social and economic improvements; however, the region still faces major challenges in developing effective strategies and significant investments in public health infrastructure to prevent and control these diseases. In this article, we review the current knowledge and potential impacts of deforestation, urbanization, and other land use changes on mosquito-borne and tick-borne disease transmission in Central America and how these anthropogenic drivers could affect the risk for disease emergence and resurgence in the region. These issues are addressed in the context of other interconnected environmental and social challenges.

Tick exposure and risk of tick-borne pathogens infection in hunters and hunting dogs: a citizen science approach

Citizen science may be described as a research involving communities and individuals, other than scientists. Following this approach, along with the evidence of a high prevalence of Rickettsia spp. in Dermacentor marginatus from wild boars in hunting areas of southern Italy, this study aimed to assess the occurrence of tick‐borne pathogens (TBPs) in ticks collected from hunters and their hunting dogs. From October 2020 to May 2021, ticks were collected from wild boar hunters (n = 347) and their dogs (n = 422) in regions of southern Italy (i.e., Apulia, Basilicata, Calabria, Campania and Sicily). All ticks were morphologically identified, classified according to gender, feeding status, host, geographic origin, and molecularly screened for zoonotic bacteria. Adult ticks (n = 411) were collected from hunters (i.e., n = 29; 8.4%; mean of 1.6 ticks for person) and dogs (i.e., n = 200; 47.4%; mean of 1.8 ticks for animal) and identified at species level as D. marginatus (n = 240, 58.4%), Rhipicephalus sanguineus sensu lato (n = 135, 32.8%), Rhipicephalus turanicus (n = 27, 6.6%) and Ixodes ricinus (n = 9, 2.2%). Overall, 45 ticks (i.e., 10.9%, 95% CI: 8.3‐14.3) tested positive for at least one tick‐borne agent, being Rickettsia slovaca the most frequent species (n = 37, 9.0%), followed by Rickettsia raoultii, Rickettsia aeschlimannii, Rickettsia monacensis, Coxiella burnetii, Borrelia lusitaniae and Candidatus Midichloria mitochondrii (n = 2, 0.5% each). Data herein presented demonstrate a relevant risk of exposure to TBPs for hunters and hunting dogs during the hunting activities. Therefore, the role of hunters to monitor the circulation of ticks in rural areas may be considered an effective example of the citizen science approach, supporting the cooperation toward private and public health stakeholders.

Hunting Dogs

Herding and hunting dogs are intense, high-drive dogs that work, and often live, outdoors and in constant or repeated close contact with domestic and wild animals. These dogs are at increased risk for injury and exposure to infectious diseases, toxic substances, and environmental threats. The common practice of feeding or allowing access to raw meat from farm or game animals enhances disease transmission risk. These dogs can be affected by infectious diseases and injurious agents that are rarely encountered in other groups of dogs. In addition, their extreme work ethic may lead to delays in diagnosis.

Predominant risk factors for tick-borne co-infections in hunting dogs from the USA

BACKGROUND

Both incidence and geographical range of tick-borne disease has increased across the USA. Similar to people, dogs are hosts for Anaplasma spp., Babesia spp., Ehrlichia spp. and Borrelia burgdorferi. Dogs also share our homes and beds, making them both a sentinel for the ticks in our backyards but also increasing our exposure to ticks. Measures to better track, prevent, and/or treat tick-borne diseases in companion animals can lead to better control and prevention of human tick-borne disease. This study identifies demographic and co-infection risk factors for canine seropositivity to tick-borne infections in a cohort of hunting dogs across the USA.

RESULTS

Human patterns of tick-borne disease co-infection in the USA have been predominantly driven by the geographical distribution of the tick vector. Dogs who tested seropositive for Anaplasma spp. were 1.40 times more likely (P = 0.0242) to also test seropositive for Babesia spp. and vice versa (1.60 times more likely, P = 0.0014). Dogs living in the West had 5% lower risk (P = 0.0001) for Ehrlichia spp. seropositivity compared to other regions. Controlling for age and Anaplasma spp. seroprevalence, dogs in all three other regions were 2.30 times more likely (P = 0.0216) to test seropositive for B. burgdorferi than dogs in the West. Dogs seropositive for B. burgdorferi were 1.60 times more likely (P = 0.0473) to be seropositive for Anaplasma spp.

CONCLUSIONS

Tick geographical distributions have a prominent impact on the regional distribution of hunting dog exposure to tick-borne diseases. Education concerning regional tick prevalence and disease risk is important for everyone, but particularly dog owners, regarding ticks in their region and protection from infection and co-infection of tick-borne pathogens as they travel or move with their dogs. Dogs are sentinel species for human exposure to ticks, and as such surveillance of canine tick-borne infections and understanding the probability that these infections might be seen together as co-infections helps predict emerging areas where people are more likely to be exposed as well.