First report of dog ticks and tick-borne pathogens they are carrying in Malawi

Ticks are vectors for transmitting tick-borne pathogens (TBPs) in animals and humans. Therefore, tick identification is necessary to understand the distribution of tick species and the pathogens they carry. Unfortunately, data on dog ticks and the TBPs they harbor in Malawi are incomplete. This study aimed to identify dog ticks and the TBPs they transmit in Malawi. One hundred thirty-two ticks were collected from 87 apparently healthy but infested domestic dogs in four districts of Malawi, which were pooled into 128 tick samples. The ticks were morphologically identified under a stereomicroscope using identification keys, and species identification was authenticated by polymerase chain reaction (PCR) through the amplification and sequencing of 12S rRNA and cytochrome c oxidase subunit I (CO1) genes. The tick species identified were Rhipicephalus sanguineus sensu lato (58.3%), Haemaphysalis elliptica (32.6%), and Hyalomma truncatum (9.1%). Screening for TBPs using species-specific PCR assays revealed that 48.4% of the ticks were infected with at least one TBP. The TBP detection rates were 13.3% for Anaplasma platys, 10.2% for Babesia rossi, 8.6% for B. vogeli, 6.3% for Ehrlichia canis, 3.9% for A. phagocytophilum, 3.1% for B. gibsoni, 2.3% for B. canis and 0.8% for Hepatozoon canis. Co-infections of up to three pathogens were observed in 48.4% of the positive samples. This is the first study to identify dog ticks and the TBPs they harbor in Malawi. These findings provide the basis for understanding dog tick distribution and pathogens they carry in Malawi. This study necessitates the examination of ticks from more study locations to have a better picture of tick challenge, and the development of ticks and tick-borne disease control methods in Malawi.

Mapping the Potential Distribution of Ticks in the Western Kanto Region, Japan: Predictions Based on Land-Use, Climate, and Wildlife

Simple Summary

Recently, the risk of tick-borne diseases (TBD) has drawn increasing attention from a public health perspective. Information about where ticks are distributed is important for the prevention of TBDs. In this study, we used the MaxEnt model to predict the potential distribution of six major tick species out of 16 tick species collected in the Kanto region, the central part of Japan, based on land-use, climate, and wildlife distribution, and to investigate the factors that contribute to each distribution of ticks. The distribution of raccoons contributed to the distribution of five tick species, and forest connectivity was a strong contributor to the distribution of all species.

Abstract

Background: Tick distributions have changed rapidly with changes in human activity, land-use patterns, climate, and wildlife distributions over the last few decades. Methods: To estimate potential distributions of ticks, we conducted a tick survey at 134 locations in western Kanto, Japan. We estimated the potential distributions of six tick species (Amblyomma testudinarium Koch, 1844; Haemaphysalis flava Neumann, 1897; Haemaphysalis kitaokai Hoogstraal, 1969; Haemaphysalis longicornis Neumann, 1901; Haemaphysalis megaspinosa Saito, 1969; and Ixodes ovatus Neumann, 1899) using MaxEnt modeling based on climate patterns, land-use patterns, and the distributions of five common wildlife species: sika deer (Cervus nippon Temminck, 1838), wild boar (Sus scrofa Linnaeus, 1758), raccoon (Procyon lotor Linnaeus, 1758), Japanese raccoon dog (Nyctereutes procyonoides Gray, 1834), and masked palm civet (Paguma larvata C.E.H. Smith, 1827)). Results: We collected 24,546 individuals of four genera and 16 tick species. Our models indicated that forest connectivity contributed to the distributions of six tick species and that raccoon distribution contributed to five tick species. Other than that, sika deer distribution contributed to H. kitaokai, and wild boar distribution, bamboo forest, and warm winter climate contributed specifically to A. testudinarium. Conclusions: Based on these results, the dispersal of some tick species toward residential areas and expanded distributions can be explained by the distribution of raccoons and by forest connectivity.

Identification, Distribution, and Habitat Suitability Models of Ixodid Tick Species in Cattle in Eastern Bhutan

Tick infestation is the most reported parasitological problem in cattle in Bhutan. In May and June 2019, we collected ticks from 240 cattle in two districts of Eastern Bhutan. Tick presence, diversity, and infestation prevalence were examined by morphological identification of 3600 live adult ticks. The relationships between cattle, geographic factors, and infestation prevalence were assessed using logistic regression analyses. Habitat suitability for the tick species identified was determined using MaxEnt. Four genera and six species of ticks were found. These were Rhipicephalus microplus (Canestrini) (70.2% (95% confidence interval (CI): 68.7-71.7)), Rhipicephalus haemaphysaloides Supino (18.8% (95% CI: 17.5-20.1)), Haemaphysalis bispinosa Neumann (8.2% (95% CI: 7.3-9.1)), Haemaphysalis spinigera Neumann (2.5% (95% CI: 2-3)), Amblyomma testudinarium Koch (0.19% (95% CI: 0.07-0.4)), and a single unidentified Ixodes sp. Logistic regression indicated that the variables associated with infestation were: longitude and cattle age for R. microplus; latitude for R. haemaphysaloides; and altitude and cattle breed for H. bispinosa and H. spinigera. MaxEnt models showed land cover to be an important predictor for the occurrence of all tick species examined. These findings provide information that can be used to initiate and plan enhanced tick surveillance and subsequent prevention and control programs for ticks and tick-borne diseases in cattle in Bhutan.

Ticks and Tick-Borne Diseases of Livestock in the Middle East and North Africa: A Review

Ticks are important vectors of an array of viral, bacterial and protozoan pathogens resulting in a wide range of animal and human diseases. There is limited information in the literature about tick species in the Middle East and North Africa (MENA) countries, even though they have suitable climate and vegetation for ticks and their hosts. We reviewed the occurrence of tick species and the pathogens they transmit from the MENA on published papers from 1901-2020. We found taxonomic records of 55 tick species infesting livestock representing the following eight genera: Ornithodoros, Otobius, Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, and Rhipicephalus. In addition, 15 pathogens were recorded causing diseases of significance, with Crimean-Congo hemorrhagic fever, theileriosis, babesiosis and anaplasmosis being widely distributed diseases in the region. In recent decades, there has been increasing trends in disease occurrence and movement associated with global movement of humans and global trade of animals. We suggest that disease control and prevention could be achieved effectively through good integration between public health, veterinary medicine and animal management, and ecological approaches. We recommend further research in the areas of tick ecology and tick born-disease transmission. Furthermore, we suggest evaluation and improvement of disease control policies in the region.

Density of Dermacentor reticulatus Ticks in Eastern Poland

Dermacentor reticulatus, the ornate cow tick, is second only to Ixodes ricinus as the most important reservoir and vector of infectious diseases in Europe. In recent years, the distribution of D. reticulatus ticks has expanded into new territories, including increased population densities in areas of their previous occurrence. Our investigations around this consisted of two stages. In the first stage, we monitored the seasonal activity of D. reticulatus ticks in Polesie National Park in 2014-2019. The second stage, which was carried out in 2019 at the peak of the spring (March) and autumn (October) activity of this species, included assessment of the density of D. reticulatus ticks in the entire province. To this end, the study area was divided into 101 equal plots that were surveyed for ticks. The seasonal activity of D. reticulatus in Polesie National Park showed peaks of activity in autumn in 2014-2018 and in spring in 2019. A total of 19,559 adult D. reticulatus specimens were collected, with a mean of 96.8 specimens/100 m² in Lublin Province. The area of Lublin Province is characterized by a high density of the ornate cow tick. An increase in the surface area of meadows and fallow land has contributed to a rise in the number of local populations of D. reticulatus ticks.

Vectors of Babesiosis

Babesiosis, caused by piroplasmid protozoans in the genus Babesia, is arguably the most important vector-borne disease of livestock and companion animals and is growing in importance as a zoonosis. Ixodid ticks were identified as vectors more than a hundred years ago, but the particular tick species transmitting some significant pathogens are still unknown. Moreover, it is only recently that the complexity of the pathogen-tick relationship has been revealed as a result of studies enabled by gene expression and RNA interference methodology. In this article, we provide details of demonstrated and incriminated vectors, maps of the current knowledge of vector distribution, a summary of established features of the pathogen life cycle in the vector, and an outline of molecular research on pathogen-tick relationships. The article concludes with a discussion of vector ecology and disease epidemiology in a global-change context and with suggestions for future research.

Multi-Scale Clustering of Lyme Disease Risk at the Expanding Leading Edge of the Range of Ixodes scapularis in Canada

Since its detection in Canada in the early 1990s, Ixodes scapularis, the primary tick vector of Lyme disease in eastern North America, has continued to expand northward. Estimates of the tick's broad-scale distribution are useful for tracking the extent of the Lyme disease risk zone; however, tick distribution may vary widely within this zone. Here, we investigated I. scapularis nymph distribution at three spatial scales across the Lyme disease emergence zone in southern Quebec, Canada. We collected ticks and compared the nymph densities among different woodlands and different plots and transects within the same woodland. Hot spot analysis highlighted significant nymph clustering at each spatial scale. In regression models, nymph abundance was associated with litter depth, humidity, and elevation, which contribute to a suitable habitat for ticks, but also with the distance from the trail and the type of trail, which could be linked to host distribution and human disturbance. Accounting for this heterogeneous nymph distribution at a fine spatial scale could help improve Lyme disease management strategies but also help people to understand the risk variation around them and to adopt appropriate behaviors, such as staying on the trail in infested parks to limit their exposure to the vector and associated pathogens.

A Survey of Tick Species in a Recently Reintroduced Elk ( Cervus canadensis) Population in Southeastern Kentucky, USA, with Potential Implications for Interstate Translocation of Zoonotic Disease Vectors

In the late 20th century, elk ( Cervus canadensis) were reintroduced into southeastern Kentucky, US. This population has since been used as a stock population for additional elk reintroductions in other eastern states. Although reintroduction and translocation practices are effective, they can disseminate vectors and pathogens. Therefore, we surveyed tick species residing on elk hosts a decade after elk reintroduction in Kentucky by examining 263 captured individuals (female=86; male=177) from 2011 to 2013. A total of 1,617 ticks were collected from 255 elk. We found five tick species: American dog ( Dermacentor variabilis), Gulf Coast ( Amblyomma maculatum), winter ( Dermacentor albipictus), deer ( Ixodes scapularis), and Lone Star ( Amblyomma americanum). The most prevalent ticks were winter tick (52.3%) and American dog tick (42.1%). We found no difference between female and male elk in mean intensity of American dog tick (mean=2.6, 95% confidence limits: -2.6, 2.7; P=0.701) or winter tick (mean=3.28, 95% confidence limits: -2.21, 2.07; P=0.274). Our findings demonstrated that the elk population acts as host to a diversity of tick species, suggested a broader distribution of tick species than previously reported in Kentucky, and highlighted the potential for inadvertent spread of ticks through translocation and reintroduction efforts, even on a local scale.

Distribution and Habitat of Ixodes pacificus (Acari: Ixodidae) and Prevalence of Borrelia burgdorferi in Utah

Knowledge about the distribution and abundance of the western black-legged tick, Ixodes pacificus Cooley and Kohls, in Utah is limited. Recent concerns over tick-borne diseases in Utah, primarily Lyme disease, have reinvigorated the need to understand the distribution and habitats favored by this tick species. We surveyed 157 sites throughout Utah to examine the distribution, abundance, and habitat of I. pacificus. In total, 343 adult ticks were collected from 2011 to 2013. Specifically, 119 I. pacificus, 217 Dermacentor andersoni Stiles, six D. albipictus Packard, and one D. hunteri Bishopp were collected. Overall, tick abundance was relatively low in the areas evaluated in Utah. I. pacificus collections were limited to sites above 1700 m. Ninety-two percent of I. pacificus were captured in the Sheeprock Mountains in Tooele County. I. pacificus positive collection sites were characterized by Gambel oak (Quercus gambelii Nuttall), juniper (Juniperus spp. L.), big sagebrush (Artemisia tridentata Nuttall) and black sagebrush (A. nova Nelson), and mixed grass habitat. All I. pacificus ticks were tested for the presence of Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt, and Brenner, sensu stricto) using real-time PCR. All ticks tested negative for B. burgdorferi. The likelihood of encountering I. pacificus and acquiring Lyme disease in the areas evaluated in Utah is considerably low due to low tick abundance and limited distribution, as well as low prevalence (or absence) of B. burgdorferi in Utah.

Rhipicephalus rossicus, a neglected tick at the margin of Europe: a review of its distribution, ecology and medical importance

Rhipicephalus rossicus (Ixodida: Ixodidae) is a three-host tick with a broad host spectrum that includes wild animals, pets, livestock and humans. Despite its local abundance in certain areas, most of the available information on R. rossicus was published decades ago, mainly by former soviet authors. Its distribution largely overlaps the Eurasian steppe. However, its range may be more extensive than is currently known because this species may have been misidentified as Rhipicephalus sanguineus, principally in areas where the latter species is present. Although R. rossicus has been occasionally reported to feed on people, little attention has been given to its medical importance. It has been shown to have a vectorial role in the transmission of Francisella tularensis, Crimean-Congo haemorrhagic fever virus and West Nile virus. However, the vectorial importance of R. rossicus may be significantly greater, mainly as the closely related species R. sanguineus s.l. is known to transmit a very wide spectrum of pathogens. The probably underestimated vectorial role of R. rossicus may represent a hidden public health threat.

Amblyomma triste (Acari: Ixodidae): new North American collection records, including the first from the United States

New distribution records for the Neotropical tick, Amblyomma triste Koch, are identified from 27 specimens in 18 separate collections. These collections originated from six now recognized geographical foci in two states in the United States (Cochise and Santa Cruz Counties, Arizona, and Brewster and Jeff Davis Counties, Texas) and from import cattle, Bos taurus L., presented for entry at the United States border and originating in three Mexican states (Coahuila, Durango, and Sonora). For at least 67 yr, A. triste has existed in some areas of the United States as a cryptic species, and specimens there have been confused with and identified as Gulf Coast ticks, Amblyomma maculatum Koch, even by noted tick specialists. Most of the records reported in this study were from reidentified, archived specimens of putative A. maculatum.

Amblyomma triste (Acari: Ixodidae): new North American collection records, including the first from the United States

New distribution records for the Neotropical tick, Amblyomma triste Koch, are identified from 27 specimens in 18 separate collections. These collections originated from six now recognized geographical foci in two states in the United States (Cochise and Santa Cruz Counties, Arizona, and Brewster and Jeff Davis Counties, Texas) and from import cattle, Bos taurus L., presented for entry at the United States border and originating in three Mexican states (Coahuila, Durango, and Sonora). For at least 67 yr, A. triste has existed in some areas of the United States as a cryptic species, and specimens there have been confused with and identified as Gulf Coast ticks, Amblyomma maculatum Koch, even by noted tick specialists. Most of the records reported in this study were from reidentified, archived specimens of putative A. maculatum.