Asian Longhorned Tick

The Asian longhorned tick (Haemophysalis longicorns Neumann; alternative names include Asian longhorned tick, Asian tick, bush tick, New Zealand cattle tick) is a species of hard tick in the family Ixodidae. It is native to eastern China, Japan, the Russian Far East and Korea. It has also established in Australia, New Zealand and several Pacific islands, where it is considered a severe exotic pest of livestock. In late 2017, the United States Department of Agriculture’s National Veterinary Services Laboratories (NVSL) confirmed the presence of the Asian longhorned tick in the United States. These ticks were first identified in New Jersey, but have since been found in archival samples from West Virginia as far back as 2010. The origin of the tick in the US remains unknown. Some possible routes of entry include entering on domestic pets, horses, livestock or humans. The real impact of the introduction of this tick into the US is not clear at this time, but animal health officials are concerned about potential detrimental impacts on livestock and wildlife

Habitat and Vegetation Variables Are Not Enough When Predicting Tick Populations in the Southeastern United States

La Crosse encephalitis (LAC) is the leading arboviral disease among children, and was previously limited to the upper Midwest. In 2012 nine pediatric cases of LAC occurred in eastern Tennessee, including one fatal case. In an attempt to identify sites near an active LACv infection and describe the abundance and distribution of potential LACv vectors near a fatal LAC case in the Appalachian region, we initiated an end of season study using a combination of questing and oviposition mosquito traps placed at forty-nine sites consisting of cemeteries and houses within 16 radial kilometers of two pediatric infections. LACv was isolated from three Aedes triseriatus pools collected from cemeteries and spatial clustering analysis identified clusters of Ae. triseriatus and Ae. albopictus populations that overlapped in the same area as the 2012 LACv cases. Results indicate cemeteries are effective sites for monitoring LACv. The role of cemeteries and specific environmental features will be the focus of future investigations

Cemeteries Are Effective Sites For Monitoring La Crosse Virus (LACv) and these Environments May Play a Role in LACv Infection

La Crosse encephalitis (LAC) is the leading arboviral disease among children, and was previously limited to the upper Midwest. In 2012 nine pediatric cases of LAC occurred in eastern Tennessee, including one fatal case. In an attempt to identify sites near an active LACv infection and describe the abundance and distribution of potential LACv vectors near a fatal LAC case in the Appalachian region, we initiated an end of season study using a combination of questing and oviposition mosquito traps placed at forty-nine sites consisting of cemeteries and houses within 16 radial kilometers of two pediatric infections. LACv was isolated from threeAedes triseriatus pools collected from cemeteries and spatial clustering analysis identified clusters of Ae. triseriatus and Ae. albopictus populations that overlapped in the same area as the 2012 LACv cases. Results indicate cemeteries are effective sites for monitoring LACv. The role of cemeteries and specific environmental features will be the focus of future investigations

Cow-Calf Producers’ Willingness to Pay for Bulls Resistant to Horn Flies (Diptera: Muscidae)

Horn flies (Haematobia irritans (L.)) have long posed animal health and welfare concerns. Economic losses to the cattle and dairy industries from their blood-feeding behavior include decreased weight gain, loss in milk productivity, and transmission of bacteria causing mastitis in cattle. Horn fly management strategies are labor intensive and can become ineffective due to the horn fly’s ability to develop insecticide resistance. Research indicates that for some cattle herds, genetically similar animals consistently have fewer flies suggesting those animals are horn fly resistant (HFR) and that the trait is heritable; however, it is currently unknown if cattle producers value this trait. Tennessee and Texas cow-calf producers were surveyed to estimate their willingness to pay for HFR bulls and to identify the factors affecting their decision to adopt a HFR bull in their herds. Results indicate that Tennessee and Texas cow-calf producers were willing to pay a premium of 51% and 59% above the base price, respectively, for a HFR bull with the intent to control horn flies within their herd. Producer perceptions of horn fly intensities and the HFR trait, along with their pest management practices, were factors that affected Tennessee and Texas producer willingness to adopt a HFR bull. In Texas, demographics of the producers and their farms also had a role. Knowing producers are willing to pay a premium for the HFR bull indicates that producers value the HFR trait and warrants additional research on the development, implementation, and assessment of the trait

Identifying avian malaria vectors: sampling methods influence outcomes

Background The role of vectors in the transmission of avian malaria parasites is currently understudied. Many studies that investigate parasite-vector relationships use limited trapping techniques and/or identify potential competent vectors in the field in such ways that cannot distinguish between an infected or infectious vector. Without the use of multiple trapping techniques that address the specific biology of diverse mosquito species, and without looking at the infection status of individual mosquitoes, it is not possible to make dependable conclusions on the role of mosquitoes in the transmission of avian malaria parasites. Methods We conducted two years of mosquito collections at a riparian preserve in California where a wide diversity of species were collected with multiple trap types. We hypothesized that competent mosquito species can influence the distribution and diversity of avian malaria parasites by acting as a compatibility filter for specific Plasmodium species. To determine the infection status of all individual mosquitoes for Plasmodium species/lineages, amplification within the cytochrome b gene was carried out on over 3000 individual mosquito thoraxes, and for those that tested positive we then repeated the same process for abdomens and salivary glands. Results Our data show heterogeneity in the transmissibility of Plasmodium among ornithophillic mosquito species. More specifically, Culex stigmatosoma appears to not be a vector of Plasmodium homopolare, a parasite that is prevalent in the avian population, but is a vector of multiple other Plasmodium species/lineages. Conclusions Our results suggest that conclusions made on the role of vectors from studies that do not use different mosquito trapping methods should be re-evaluated with caution, as we documented the potential for trapping biases, which may cause studies to miss important roles of specific mosquito species in the transmission of avian malaria. Moreover, we document heterogeneity in the transmission of Plasmodium spp. by mosquitoes can influence Plasmodium diversity and prevalence in specific locations to Plasmodium-vector incompatibilities

Horn Fly (Diptera: Muscidae) - Biology, Management, and Future Research Directions

The horn fly, Haematobia irritans irritans (L.), is one of the most important external parasites of cattle in North America and elsewhere. Horn fly adults have an intimate association with cattle, their primary host. With their often-high numbers and by feeding up to 38 times per day per fly, horn flies stress cattle. The resulting productivity loss is valued at more than 2.3 billion USD in the United States. Insecticides are commonly used to mitigate direct injury from feeding and indirect injury from disease transmission. This paper discusses horn fly biology, distribution, and management. Emphasis is on promising new approaches in novel insecticides, repellents, biological control, vaccines, animal genetics, and sterile insect technology that will lead to effective preventative tactics and the integration of smart technologies with horn fly management. We conclude with a discussion of research needs necessary to shift horn fly integrated pest management to an emphasis on preventative tactics and the precision use of reactive techniques

Species Distribution Models and Ecological Suitability Analysis for Potential Tick Vectors of Lyme Disease in Mexico

Species distribution models were constructed for ten Ixodes species and Amblyomma cajennense for a region including Mexico and Texas. The model was based on a maximum entropy algorithm that used environmental layers to predict the relative probability of presence for each taxon. For Mexico, species geographic ranges were predicted by restricting the models to cells which have a higher probability than the lowest probability of the cells in which a presence record was located. There was spatial nonconcordance between the distributions of Amblyomma cajennense and the Ixodes group with the former restricted to lowlands and mainly the eastern coast of Mexico and the latter to montane regions with lower temperature. The risk of Lyme disease is, therefore, mainly present in the highlands where some Ixodes species are known vectors; if Amblyomma cajennense turns out to be a competent vector, the area of risk also extends to the lowlands and the east coast

Molecular detection of tick-borne pathogen diversities in ticks from livestock and reptiles along the shores and adjacent islands of lake Victoria and lake Baringo, Kenya

Tick-borne pathogens (TBPs) are responsible for some of the most serious emerging infectious diseases facing sub-Saharan Africa (SSA) and the rest of the world today (1, 2). In Kenya, TBPs (including viral diseases—arboviruses) like Crimean Congo hemorrhagic fever (CCHF), Dugbe, Kupe, and Hazara, as well as hemoparasites that cause babesiosis, theileriosis, and rickettsiosis, are major impediments to livestock productivity and public health

Differential Plasmodium falciparum infection of Anopheles gambiae s.s. molecular and chromosomal forms in Mali

BACKGROUND: Anopheles gambiae sensu stricto (s.s.) is a primary vector of Plasmodium falciparum in sub-Saharan Africa. Although some physiological differences among molecular and chromosomal forms of this species have been demonstrated, the relative susceptibility to malaria parasite infection among them has not been unequivocally shown. The objective of this study was to investigate P. falciparum circumsporozoite protein infection (CSP) positivity among An. gambiae s.s. chromosomal and molecular forms. METHODS: Wild An. gambiae from two sites Kela (n = 464) and Sidarebougou (n = 266) in Mali were screened for the presence of P. falciparum CSP using an enzyme-linked immunosorbent assay (ELISA). Samples were then identified to molecular form using multiple PCR diagnostics (n = 713) and chromosomal form using chromosomal karyotyping (n = 419). RESULTS: Of 730 An. gambiae sensu lato (s.l.) mosquitoes, 89 (12.2%) were CSP ELISA positive. The percentage of positive mosquitoes varied by site: 52 (11.2%) in Kela and 37 (13.9%) in Sidarebougou. Eighty-seven of the positive mosquitoes were identified to molecular form and they consisted of nine Anopheles arabiensis (21.4%), 46 S (10.9%), 31 M (12.8%), and one MS hybrid (14.3%). Sixty of the positive mosquitoes were identified to chromosomal form and they consisted of five An. arabiensis (20.0%), 21 Savanna (15.1%), 21 Mopti (30.4%), 11 Bamako (9.2%), and two hybrids (20.0%). DISCUSSION: In this collection, the prevalence of P. falciparum infection in the M form was equivalent to infection in the S form (no molecular form differential infection). There was a significant differential infection by chromosomal form such that, P. falciparum infection was more prevalent in the Mopti chromosomal forms than in the Bamako or Savanna forms; the Mopti form was also the most underrepresented in the collection. Continued research on the differential P. falciparum infection of An. gambiae s.s. chromosomal and molecular forms may suggest that Plasmodium – An. gambiae interactions play a role in malaria transmission