Prevalence and Genetic Diversity of Deer Tick Virus (Powassan Virus, Lineage II) in Ixodes scapularis Ticks in Five Habitats at a Nature Reserve in Southern Maine, United States.

Deer tick virus (DTV), also known as Powassan virus lineage II, is a rising health concern due to increased recognition as a cause of human encephalitis. Since European tick-borne encephalitis virus persists in nature in enzootic foci (i.e.

Features of Consistent Powassan Virus Lineage II Focus in Southern Maine, United States.

Powassan virus lineage II or deer tick virus (DTV) is a rare but increasingly reported human infection in the United States transmitted by Ixodes scapularis ticks. The virus is thought to be maintained in environmental foci that are optimal for tick and vertebrate reservoirs, but details on DTV ecology are poorly understood. We investigated DTV tick infection rates and reservoir host abundance in a focus of consistent DTV activity in Maine, USA.

Phylogeographic reconstruction of the emergence and spread of Powassan virus in the northeastern United States.

Powassan virus is an emerging tick-borne virus of concern for public health, but very little is known about its transmission patterns and ecology. Here, we expanded the genomic dataset by sequencing 279 Powassan viruses isolated from ticks from the northeastern United States. Our phylogeographic reconstructions revealed that Powassan virus lineage II was likely introduced or emerged from a relict population in the Northeast between 1940 and 1975.

Phylodynamics of deer tick virus in North America.

The burden of ticks and the pathogens they carry is increasing worldwide. Powassan virus (POWV; Flaviviridae: ), the only known North American tick-borne flavivirus, is of particular concern due to rising cases and the severe morbidity of POWV encephalitis. Here, we use a multifaceted approach to evaluate the emergence of the II POWV lineage, known as deer tick virus (DTV), in parts of North America where human cases occur.

Jamestown Canyon Virus in Collected Mosquitoes, Maine, United States, 2017-2019.

Jamestown Canyon virus (JCV) is a mosquito-borne arbovirus that circulates in North America. We detected JCV in 4 pools of mosquitoes collected from midcoastal Maine, USA, during 2017-2019. Phylogenetic analysis of a JCV sequence obtained from Aedes cantator mosquitoes clustered within clade A, which also circulates in Connecticut, USA.

Surge in Anaplasmosis Cases in Maine, USA, 2013-2017.

Incidence of human granulocytic anaplasmosis is rising in Maine, USA. This increase may be explained in part by adoption of tick panels as a frequent diagnostic test in persons with febrile illness and in part by range expansion of Ixodes scapularis ticks and zoonotic amplification of Anaplasma phagocytophilum.

Decoupling of Blacklegged Tick Abundance and Lyme Disease Incidence in Southern Maine, USA.

Lyme disease is caused by the bacterial spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt, and Brenner (Spirocheatales: Spirochaetaceae) which is transmitted through the bite of an infected blacklegged tick Ixodes scapularis Say (Ixodida: Ixodidae). Maine, USA, is a high Lyme disease incidence state, with rising incidence of Lyme disease and other tick-borne illnesses associated with increasing I. scapularis abundance and northward range expansion.

Sugar feeding improves survival of nondiapausing cold-stored Culex pipiens.

The continuous culture of mosquitoes is a costly endeavor for vector biology laboratories. In addition to the resources that must be committed to colony maintenance, biological costs, including genetic drift and accidental colony loss, also can occur. Although alternatives do exist, their application to mosquitoes is limited.

Cold storage of Culex pipiens in the absence of diapause.

A major expenditure in vector biology laboratories is the rearing of mosquitoes. Most mosquito colonies require substantial effort to maintain, including frequent bloodmeals for optimal performance. Successful cryopreservation of mosquitoes continues to be elusive.

Isolation of diapause-regulated genes from the flesh fly, Sarcophaga crassipalpis by suppressive subtractive hybridization.

Subtractive suppressive hybridization (SSH) was used to characterize the diapause transcriptome of the flesh fly Sarcophaga crassipalpis. Through these efforts, we isolated 97 unique clones which were used as probes in northern hybridization to assess their expression during diapause. Of these, 17 were confirmed to be diapause upregulated and 1 was diapause downregulated, while 12 were shown to be unaffected by diapause in this species.

Up-regulation of heat shock proteins is essential for cold survival during insect diapause.

Diapause, the dormancy common to overwintering insects, evokes a unique pattern of gene expression. In the flesh fly, most, but not all, of the fly's heat shock proteins (Hsps) are up-regulated. The diapause up-regulated Hsps include two members of the Hsp70 family, one member of the Hsp60 family (TCP-1), at least four members of the small Hsp family, and a small Hsp pseudogene.

Endemic eastern equine encephalitis in the Amazon region of Peru.

Eastern equine encephalitis virus (EEEV) causes severe neurologic disease in North America, but only two fatal human cases have been documented in South America. To test the hypothesis that alphavirus heterologous antibodies cross-protect, animals were vaccinated against other alphaviruses and challenged up to 3 months later with EEEV. Short-lived cross-protection was detected, even in the absence of cross-neutralizing antibodies.

Diapause-specific gene expression in the northern house mosquito, Culex pipiens L., identified by suppressive subtractive hybridization.

In this study we probe the molecular events underpinning diapause observed in overwintering females of Culex pipiens. Using suppressive subtractive hybridization (SSH) we have identified 40 genes that are either upregulated or downregulated during this seasonal period of dormancy. Northern blot hybridizations have confirmed the expression of 32 of our SSH clones, including six genes that are upregulated specifically in early diapause, 17 that are upregulated in late diapause, and two upregulated throughout diapause.

Upregulation of two actin genes and redistribution of actin during diapause and cold stress in the northern house mosquito, Culex pipiens.

Two actin genes cloned from Culex pipiens L. are upregulated during adult diapause. Though actins 1 and 2 were expressed throughout diapause, both genes were most highly expressed early in diapause.

Enhanced cold and desiccation tolerance in diapausing adults of Culex pipiens, and a role for Hsp70 in response to cold shock but not as a component of the diapause program.

Culex pipiens L. reared under diapause-inducing conditions (short daylength; 18 degrees C) were more cold tolerant and desiccation resistant than their nondiapausing counterparts (long daylength; 18 degrees C). Upon cold exposure (-5 degrees C), diapausing mosquitoes reared at 18 degrees C survived nearly twice as long as nondiapausing mosquitoes reared at 18 degrees C and 10 times longer than nondiapausing mosquitoes reared at 25 degrees C.

Meconial peritrophic matrix structure, formation, and meconial degeneration in mosquito pupae/pharate adults: histological and ultrastructural aspects.

The noncellular peritrophic matrix (PM) that forms around the food bolus in the midgut of many arthropod species may influence the fate of ingested microbes. In mosquitoes, PMs have been identified in the pupal as well as larval and adult stages. In pupae, the PMs surround the meconium, the sloughed larval midgut epithelium.

Diapause in the mosquito Culex pipiens evokes a metabolic switch from blood feeding to sugar gluttony.

A key characteristic of overwintering dormancy (diapause) in the mosquito Culex pipiens is the switch in females from blood feeding to sugar gluttony. We present evidence demonstrating that genes encoding enzymes needed to digest a blood meal (trypsin and a chymotrypsin-like protease) are down-regulated in diapause-destined females, and that concurrently, a gene associated with the accumulation of lipid reserves (fatty acid synthase) is highly up-regulated. As the females then enter diapause, fatty acid synthase is only sporadically expressed, and expression of trypsin and chymotrypsin-like remains undetectable.