New report of Haemaphysalis longicornis (Ixodida: Ixodidae) in Mecklenburg County, Virginia from field collections.

Haemaphysalis longicornis (Neumann) was first established in New Jersey and has rapidly spread across most of the eastern United States. This tick has the potential to infest a wide variety of hosts and can reproduce quickly via parthenogenesis, presenting a new threat to animal health. Here we report the first record of a single H. longicornis tick in Mecklenburg County, Virginia, from incidental field collections of ticks. In addition to H. longicornis, we collected 787 Amblyomma americanum, 25 Dermacentor variabilis, 6 Ixodes affinis, 1 Haemaphysalis leporispalustris, and 1 Amblyomma maculatum using standard dragging and flagging techniques. The expansion of H. longicornis will have economic consequences for livestock producers in south-central Virginia, who must now manage this species. Enhanced surveillance is needed to fully understand its growing geographic distribution in the United States and the subsequent consequences of its spread.

Don't go chasing waterfalls: the phenology of Amblyomma americanum and increased collection of medically relevant ticks further away from hiking trails in the Piedmont of North Carolina, USA.

Hiking is a popular recreational activity in North Carolina that may expose people to ticks and tick-borne pathogens. However, there is a lack of knowledge on how ticks are distributed on and near trails. Our study tested the hypothesis that ticks are more likely to be encountered when moving further away from trails by measuring differences in relative abundance at various distances. We tested 4 distances (middle of trail, edge of trail, 5 m, 20 m), as well as an on-trail and off-trail grouping. We collected significantly more ticks and ticks were more likely to be collected at our 20 m and 5 m sampling distances rather than directly on or adjacent to trails, and significantly more were collected during off-trail collections than on-trails. When looking only at Amblyomma americanum, post hoc comparisons revealed that significantly more juvenile stages were collected at 5 m and 20 m distances, but not for adults. Our monthly sampling also allowed us to describe the phenology of A. americanum in North Carolina, which is consistent with the phenology of this species in the southeastern United States with adults peaking May-Jun, nymphs Jun-Jul, and larvae in Jul-Aug. These results generally demonstrate the importance of utilizing established trails when hiking to decrease tick-borne disease risk and should be communicated to the public as a recommendation for reducing tick-encounter risk.

Plasmodium relictum infection in Culex quinquefasciatus (Culicidae) decreases diel flight activity but increases peak dusk flight activity.

BACKGROUND: Parasites are recognized for their ability to modify host physiology and behaviours in ways that increase parasite fitness. Protozoan parasites of the genus Plasmodium are a group of widespread vector-borne parasites of vertebrates, causing disease to a wide range of hosts, but most notably to human and avian hosts. METHODS: The hypothesis that infection with the avian malaria, Plasmodium relictum (GRW4 lineage) impacts flight activity in one of their natural vectors, Culex quinquefasciatus, was tested using both parasites and mosquitoes colonized from local populations in East-Central Texas, USA. Groups of Cx. quinquefasciatus were allowed to feed directly on canaries with active P. relictum infections and control canaries with no P. relictum exposure history. Additionally, how P. relictum sporozoite invasion of mosquito salivary glands impacts mosquito flight activity behaviour was tested using a Locomotor Activity Monitor for both control and infected females. Generalized linear mixed models were used to evaluate the influence of infection status on the response variables of flight activity (continuous) and probability of flight occurring (binomial). RESULTS: Infection status was a significant predictor of flight activity and flight probability and interactions between infection status and experimental period of infection as well as infection status and dusk were statistically significant predictors of flight activity. Plasmodium relictum infected mosquitoes had a mean flight activity of 3.10 and control mosquitoes had an overall mean flight activity of 3.13. DISCUSSION: Based on these results, avian malaria parasites increase the flight activity of these mosquitoes at hours known for peak host-seeking behaviour but decrease overall diel activity. CONCLUSION: Although the ramifications of this behavioural change for P. relictum transmission are unclear, these results provide additional empirical evidence suggesting that avian malaria can influence mosquito behaviour and modulate transmission potential.

Culex quinquefasciatus (Diptera: Culicidae) survivorship following the ingestion of bird blood infected with Haemoproteus sp. parasites.

Arthropod vectors are frequently exposed to a diverse assemblage of parasites, but the consequence of these infections on their biology and behavior are poorly understood. We experimentally evaluated whether the ingestion of a common protozoan parasite of avian hosts (Haemoproteus spp.; Haemosporida: Haemoproteidae) impacted the survivorship of Culex quinquefasciatus (Say) (Diptera: Culicidae). Blood was collected from wild northern cardinals (Cardinalis cardinalis) in College Station, Texas, and screened for the presence of Haemoproteus spp. parasites using microscopic and molecular methods. Experimental groups of Cx. quinquefasciatus mosquitoes were offered Haemoproteus-positive cardinal blood through an artificial feeding apparatus, while control groups received Haemoproteus-negative cardinal blood or domestic canary (Serinus canaria domestica) blood. Culex quinquefasciatus mosquitoes exposed to Haemoproteus infected cardinal blood survived significantly fewer days than mosquitoes that ingested Haemoproteus-negative cardinal blood. The survival of mosquitoes fed on positive cardinal blood had a median survival time of 18 days post-exposure and the survival of mosquitoes fed on negative cardinal blood exceeded 50% across the 30 day observation period. Additionally, mosquitoes that fed on canary controls survived significantly fewer days than cardinal negative controls, with canary control mosquitoes having a median survival time of 17 days. This study further supports prior observations that Haemoproteus parasites can be pathogenic to bird-biting mosquitoes, and suggests that Haemoproteus parasites may indirectly suppress the transmission of co-circulating vector-borne pathogens by modulating vector survivorship. Our results also suggest that even in the absence of parasite infection, bloodmeals from different bird species can influence mosquito survivorship.

The effect of anticoagulants in artificial blood meals on the mortality, fecundity, and fertility of Culex quinquefasciatus and Aedes aegypti (Culicidae).

Blood sources used for insect colonies and their effects on fecundity and fertility have been studied in multiple mosquito species, but the effect of anticoagulants that prevent clotting of blood has received minimal attention. Here, we identify the effect two anticoagulants have on the mortality, fecundity, and fertility of Culex quinquefasciatus (Sebring and BCS strains) and Aedes aegypti Liverpool. Each mosquito species was provided with one of three treatments: direct feeding on live chicken (LC), blood from freshly exsanguinated chicken treated with heparin (EXS) or commercially purchased chicken blood treated with Alsever's solution (ART). No significant effect of treatment on mortality was observed. Both Cx. quinquefasciatus Sebring and BCS strains demonstrated a significant effect of treatment type on fecundity with the number of eggs laid for LC being 1.40-fold higher than EXS and 2.14-fold higher than ART for Sebring. For BCS strain mosquitoes, LC was 1.55-fold higher than ART, and EXS was 1.57-fold higher than ART, but there was no significant difference between LC and EXS. For Ae. aegypti mosquitoes, only a significant difference in mean egg counts was observed between LC and ART treatments, with LC laying 1.46-fold more eggs. No significant effect on fertility was observed among any mosquitoes for any treatment. These results demonstrate the negative effect of anticoagulants on the fecundity for multiple mosquito taxa. This may affect the ability of labs to produce large numbers of mosquitoes or colonize wild mosquito populations and should be taken into account when considering colony maintenance or vector biology research.