Powassan virus (POWV) belongs to the group of flaviviruses, and is a rare but possibly fatal cause of tick-borne encephalitis (TBE) in the Northeastern United States (New York, Minnesota, Wisconsin, Michigan, Maine, Vermont, Connecticut, Massachusetts, and Pennsylvania), Canada (Ontario, Quebec, and New Brunswick provinces), and certain parts of Russia [1] [2] [3] [4]. The virus possesses two distinct lineages, both being transmitted from a stable animal reservoir consisting of rodents (eg. white-footed mice) and medium-sized mammals (eg. woodchucks, red squirrels groundhogs, skunks) onto the Ixodes ticks, one of the most important tick species related to human diseases [3] [5] [6]. Reports have shown that only 15 minutes are sufficient for the tick to transmit the virus to the host once it attaches to the skin [1] [4]. Wide-scale epidemiologic studies have established that many patients (due to undisclosed reasons) have an asymptomatic form of POWV infection, but in some patients, infection of the central nervous system (CNS), known as Powassan encephalitis, can develop [2] [4]. The period between the tick bite and the appearance of symptoms (known as the incubation period) typically lasts between 1-5 weeks and a prodromal period of 1-2 days, comprised of nonspecific respiratory and constitutional complaints (fever, malaise, headaches), is common [1] [2] [4]. Soon after, severe deterioration characterized by ataxia, weakness, hemiplegia, ophthalmoplegia, confusion, somnolence and a severely altered level of consciousness, as well as seizures and other focal neurological deficits, are observed in the case of Powassan encephalitis [1] [4] [6]. In addition, gastrointestinal irritation and skin rash may be seen [4]. The mortality rates of Powassan encephalitis range from 10-15% and residual neurological impairment (hemiplegia, paresis of the lower extremities, and deficits in memory and other cognitive skills) is noted in up to 50% of patients who survive the infection [2] [4] [6].

• Fever

  Abstract This article discusses two tick-borne illnesses: Powassan encephalitis, a rare cause of central nervous system infection caused by the Powassan virus, and Colorado tick fever, an acute febrile illness caused by the Colorado tick fever virus common [ncbi.nlm.nih.gov]

  This article discusses two tick-borne illnesses: Powassan encephalitis, a rare cause of central nervous system infection caused by the Powassan virus, and Colorado tick fever, an acute febrile illness caused by the Colorado tick fever virus common to [nebraska.pure.elsevier.com]

  Symptoms manifest within 7 10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. [medicine.academic.ru]

  Flaviviruses (Yellow Fever, Dengue, Dengue Hemorrhagic Fever, Japanese Encephalitis, West Nile Encephalitis, St. Louis Encephalitis, Tick-Borne Encephalitis). In: Mandell GL, Bennett JE, Dolin R, eds. [upmc-cbn.org]

  MalaCards based summary : Powassan Encephalitis, also known as powassan encephalitis virus infection, is related to encephalitis and lyme disease, and has symptoms including seizures, fever and vomiting. [malacards.org]

• Weakness

  All but one patient developed encephalitis with acute onset of profound muscle weakness, confusion, and other severe neurologic signs. [ncbi.nlm.nih.gov]

  Our fourth patient had the least of the manifestations of POWV encephalitis having mainly headaches and non-focal weakness. He has almost fully recovered except for minor residual weakness of the quadriceps muscles. [bmcresnotes.biomedcentral.com]

  Here's more from the DPH news release: Signs and symptoms include fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties and seizures....There is no specific treatment once infection with Powassan virus has occurred. [wbur.org]

  Signs and symptoms of POWV disease include but are not limited to fever, headaches, vomiting, weakness, confusion, loss of coordination, speech difficulties, and memory loss. Infection with POWV disease has been fatal in many reported cases. [dhhr.wv.gov]

• Swelling

  Signs and symptoms may include: Fever Headache Vomiting Weakness Confusion Seizures Memory loss Encephalitis (swelling of the brain) Meningitis (swelling of the membranes that surround the brain and spinal cord). [coloradoticks.org]

  “Currently the best ways to treat POWV illnesses include: medications to reduce brain swelling, respiratory support and intravenous fluids. 10% of the POWV encephalitis cases are fatal and half of the survivors have permanent symptoms that affect their [naturalsociety.com]

  It can cause swelling in the brain (doctors call this encephalitis ) and in the membranes around the brain and spinal cord (you may hear this called meningitis ). Only about 75 cases were reported in the U.S. over the last 10 years. [webmd.com]

  After hospital officials realized he did not need Narcan, they did a spinal tap and ran scans that showed swelling in his brain, he said. [capecodtimes.com]

• Falling

  Most cases in the United States occur in the northeast and Great Lakes regions primarily in the late spring, early summer, and mid-fall when ticks are most active. There are no vaccines to prevent or medicines to treat Powassan virus infection. [cdc.gov]

  Rich collaborated with Dapsis on the spring inquiry and a smaller examination of the virus conducted last fall on Cape Cod. Powassan is transmitted by the bite of a black-legged tick, also known as a deer tick. [bostonglobe.com]

  "The enhanced surveillance will continue in the fall with collection of adult ticks from many of these same sites, as well as collection and testing of blood from hunter-killed deer, for previous exposure to Powassan," Zucker said. [poughkeepsiejournal.com]

• Fatigue

  Symptoms include headache, fever, muscle aches, and fatigue. More severe symptoms, like severe headaches and altered consciousness, require immediate medical attention. [medicaldaily.com]

  The 17-year-old had not been feeling well for two weeks with a minor cough, fatigue and a headache. He had been tested for Lyme disease and strep throat by his doctor, but tests came back negative. [nydailynews.com]

  Symptoms can last up to 8 days and include fever, headache, fatigue, muscle pain, nausea, and loss of appetite. [iamat.org]

  Symptoms Fever, headache, fatigue, and malaise tend to occur and last for about five days. Following a short period of symptom-free time, more severe manifestations may develop including meningitis, encephalitis, myelitis, and cranial neuritis. [columbia-lyme.org]

  Lyme disease symptoms typically start with a rash and flu-like symptoms, such as fatigue, headaches, muscle and joint pain. [draxe.com]

• Vomiting

  MalaCards based summary : Powassan Encephalitis, also known as powassan encephalitis virus infection, is related to encephalitis and lyme disease, and has symptoms including seizures, fever and vomiting. [malacards.org]

  Serum IgM + PRNT 1:320 Steroids, IVIG Improved Patient 4 67 M DLBCL, in remission September 2014 Outdoors Y Y Vomiting, diarrhea Serum IgM + PRNT 1:160 None Improved Patient 5 65 F Migraine headache June 2014 Tick bites Y N Vomiting Serum IgM + PRNT [academic.oup.com]

  Symptoms, including fever, headache, vomiting and memory loss, can start anytime from a week to a month after the tick bite. [necn.com]

  Symptoms include headache, fever, nausea, vomiting, stiff neck, and sleepiness, breathing distress, confusion, tremors, seizures, paralysis, and possible coma. Encephalitis and meningitis can occur – 10% of encephalitis cases result in death. [lymediseaseassociation.org]

  Here's more from the DPH news release: Signs and symptoms include fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties and seizures....There is no specific treatment once infection with Powassan virus has occurred. [wbur.org]

• Nausea

  Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death. [en.wikipedia.org]

  Symptoms manifest within 7 10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. [medicine.academic.ru]

  The virus is antigenically related to the Far Eastern tick-borne encephalitis viruses. [4] Presentation Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. [ipfs.io]

  Symptoms include headache, fever, nausea, vomiting, stiff neck, and sleepiness, breathing distress, confusion, tremors, seizures, paralysis, and possible coma. Encephalitis and meningitis can occur – 10% of encephalitis cases result in death. [lymediseaseassociation.org]

  Symptoms can last up to 8 days and include fever, headache, fatigue, muscle pain, nausea, and loss of appetite. [iamat.org]

• Hypertension

  Design/Methods: A case report of a 35-year-old woman who presented with worsening headaches, vomiting, hypertension, confusion, and fever. [neurology.org]

  Vomiting Serum IgM + PRNT 1:160 None Improved Patient 6 52 M None May 2014 Tick bites Y N None Serum IgM/IgG + PRNT 1:160 b None Residual deficits Patient 7 49 M None May 2014 Tick bites Y N None Serum IgM + PRNT Negative c None Death Patient 8 44 M Hypertension [academic.oup.com]

  Case 2 A 60-year old male who enjoys outdoor activity, with a history of colon cancer (treated with hemicolectomy and chemotherapy), diabetes mellitus and hypertension, presented to the emergency department with fevers, headaches and dizziness. [bmcresnotes.biomedcentral.com]

• Diplopia

  Patient 8 A 44-year-old man from New Hampshire presented with 3 days of headache, fatigue, diplopia, and a diffuse rash over his trunk and extremities (Table 1 ). [academic.oup.com]

• Headache

  Survivors of POW: 50% have permanent neurologic problems – Headaches, muscle wasting, memory problems Supportive treatment is the only available treatment. [lymediseaseassociation.org]

  Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death. [en.wikipedia.org]

  Symptoms manifest within 7 10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. [medicine.academic.ru]

  If symptoms develop, they may include fever, headache, vomiting, weakness, confusion, loss of coordination, speech and memory problems, and seizures. [medicinenet.com]

  One could have no symptoms whatsoever, or they could develop a fever or a headache,” Gilmour said. “From there, you could move off to more severe symptoms.” Those serious symptoms include trouble speaking, confusion and lack of co-ordination. [ctvnews.ca]

• Seizure

  RESULTS: Case 1 was a 78 year old man who was presented with altered mental status and a 30 second generalized tonic-clonic seizure. He had no prior history of seizures. [neurology.org]

  MalaCards based summary : Powassan Encephalitis, also known as powassan encephalitis virus infection, is related to encephalitis and lyme disease, and has symptoms including seizures, fever and vomiting. [malacards.org]

  After the infant was treated for the seizures, he was released from the hospital, only to develop other complications 1 month later. [contagionlive.com]

  “Patients who develop seizures can be treated with anti-seizure medications, and physical and occupational therapy can help those with neurological complications,” Watkins says. [yahoo.com]

  If symptoms develop, they may include fever, headache, vomiting, weakness, confusion, loss of coordination, speech and memory problems, and seizures. [medicinenet.com]

• Confusion

  Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death. [en.wikipedia.org]

  Symptoms manifest within 7 10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. [medicine.academic.ru]

  All but one patient developed encephalitis with acute onset of profound muscle weakness, confusion, and other severe neurologic signs. [ncbi.nlm.nih.gov]

  The infection has symptom headache, has symptom fever, has symptom vomiting, has symptom stiff neck, has symptom sleepiness, has symptom breathing distress, has symptom tremors, has symptom confusion, has symptom seizures, has symptom paralysis, and has [malacards.org]

• Altered Mental Status

  RESULTS: Case 1 was a 78 year old man who was presented with altered mental status and a 30 second generalized tonic-clonic seizure. He had no prior history of seizures. [neurology.org]

  Symptomatic patients present 1 week to 1 month after infection with general symptoms of encephalitis, which include fever, headache, altered mental status, and seizures. [upmc-cbn.org]

  This manifests itself as a painful or stiff neck, altered mental status, confusion, seizures, aphasia (inability to speak), tingling and numbness, movement disorders, or cranial nerve palsies (paralysis of the muscles of the face and eyes). [pestworld.org]

  If not treated, symptoms could extend to meningoencephalitis, which may include: seizures, aphasia, cranial nerve palsies, paresis and altered mental status. [en.wikipedia.org]

• Dizziness

  POWV infection can lead to encephalitis and varied neurologic presentations including headache, dizziness, hemiplegia, intraparenchymal hemorrhage and seizures. However, there are no known reports of status epilepticus secondary to POWV infection. [neurology.org]

  Patients with symptoms of encephalitis accompanied by a fever, and dizziness who live in tick infested areas should be tested for POW. Are there any tick vaccines? Currently there are no available tick vaccines in the US. [prahs.com]

  “But if there are neurological symptoms—weakness, dizziness, seizures—then it’s important to get to the doctor.” [time.com]

  The journal of Clinical Infectious Diseases previously has reported that two Massachusetts men — one 82, the other 49 — died in 2015 and 2014 after contracting Powassan and demonstrating symptoms including dizziness, nausea, fever and headache. [capecodtimes.com]

  The spectrum of infection varies from nonspecific prodrome of upper respiratory symptoms leading to varied neurological involvement such as headache, dizziness, weakness, and hemiplegia[ 8 ]. [bmcresnotes.biomedcentral.com]

Powassan encephalitis is a very rare cause of this type of infection and the clinical presentation is indistinguishable from other causes of viral encephalitis. However, its distinct geographical and epidemiological features are quite useful in including POWV in the differential diagnosis of encephalitis. For this reason, a detailed patient history is perhaps the essential part of the diagnostic workup. Firstly, Powassan encephalitis has a seasonal appearance, meaning that most cases are diagnosed from May through September [4] [6]. Secondly, a positive travel history to the endemic areas of the United States, Canada, or Russia (or if patients are residents of those areas) could significantly aid in suspecting Powassan virus as the causative agent. And thirdly, reports of a recent tick bite must direct the attention toward tick-borne encephalitis viruses (TEBV). Thus, a thorough physical examination is also a vital component of the workup, as it might reveal the site of the tick bite. Lumbar puncture examination is a must in the evaluation of the central nervous system (CNS) infections. Elevated protein levels are infrequently observed, but either lymphocytic or polymorphonuclear pleocytosis (between 200-700 WBCs/µL) is always seen in Powassan encephalitis [4] [6]. A definite diagnosis, however, can be made through the enzyme-linked immunoassay (ELISA) testing that detects specific immunoglobulin-M (IgM) antibodies to the Powassan virus in the cerebrospinal fluid (CSF), but these tests are only available in specialized laboratories and tertiary care centers [1] [2] [4] [6]. Imaging studies might also be of use in Powassan encephalitis, as magnetic resonance imaging (MRI) reveals can ischemic or demyelinating lesions in the basal ganglia, thalamus and the brainstem on T2/FLAIR images [4] [6].

• Cerebrospinal Fluid Abnormality

  Moderate pleocytosis and increased albumin can be found in the cerebrospinal fluid; abnormalities in the thalamus, cerebellum, and brainstem in MRI may be shown as well. [columbia-lyme.org]

Survivors of POW: 50% have permanent neurologic problems – Headaches, muscle wasting, memory problems Supportive treatment is the only available treatment. [lymediseaseassociation.org]

What is the treatment for Powassan virus disease? Treatment for this disease is mainly supportive. It may include hospitalization, respiratory support, IV fluids, and other treatments to reduce symptoms. [medicinenet.com]

Treatment consists of supportive care, rest and fluids to prevent dehydration. [wbur.org]

Lyme disease has treatments, it has good treatments, and [for] Powassan we have no known effective treatments. The rare virus is transmitted through ticks, which thrive in moist weather. [news.wgbh.org]

Status Epileptics was aborted after treatment with leviteractam, lacosamide, topamax and midazolam anesthesia. Investigation results and outcomes were similar to case 1. [neurology.org]

Prognosis Cognitive Impairment in >50% of survivors, and 10-15% mortality IX. Resources X. [fpnotebook.com]

What is the prognosis for Powassan virus disease? Those individuals who develop Powassan viral disease with little or no symptoms have a good to excellent prognosis. [medicinenet.com]

Prognosis There is currently no established treatment. [5] Half of all cases results in permanent neurological damage and 10-15% result in death. References [ipfs.io]

In addition, even experienced physicians often are uncertain about the cause, appropriate therapy, and prognosis. [pedsinreview.aappublications.org]

A thorough and accurate review is difficult because the syndrome is complex and the number of etiologic agents and mimics of encephalitis are vast. [pedsinreview.aappublications.org]

CSF proteins were 57 mg/dL.CSF testing for autoimmune and other viral etiologies were normal. [neurology.org]

Isachkova, in: Etiology, Epidemiology, and Preventive Measures against Tickborne Encephalitis in the Far East [in Russian], Khabarovsk (1978), pp. 105–107. Google Scholar 30. L. M. [link.springer.com]

The majority of presumed infectious encephalitis cases do not have an identified etiology, 3 reinforcing the fact that our diagnostic ability in this arena is not optimal. [upmc-cbn.org]

Epidemiology Pathophysiology Findings Labs Differential Diagnosis Management Prognosis Resources References Extra: Related Bing Images Extra: Related Studies Extra: UMLS Ontology Extra: Navigation Tree II. [fpnotebook.com]

However, its distinct geographical and epidemiological features are quite useful in including POWV in the differential diagnosis of encephalitis. For this reason, a detailed patient history is perhaps the essential part of the diagnostic workup. [symptoma.com]

Randolph, Sarah 2004 Tick Ecology: Processes and Patterns behind the Epidemiological Risk Posed by Ixodid Ticks as Vectors. Parasitology 129 : S37 – S65. [cambridge.org]

Epidemiology of childhood enterovirus infections in Hangzhou, China. [revistabiomedica.org]

” – Professor Emeritus of Epidemiology at the Yale School of Public Health, Durland Fish, PhD. Powassan Virus photo: Canad. Med Assn. J. 5-2-64 ©LDA. 2018. 2014. 2015. [lymediseaseassociation.org]

Epidemiology Pathophysiology Findings Labs Differential Diagnosis Management Prognosis Resources References Extra: Related Bing Images Extra: Related Studies Extra: UMLS Ontology Extra: Navigation Tree II. [fpnotebook.com]

Home remedies to prevent tick bites may help prevent the disease. [medicinenet.com]

To help prevent tick bites, clothing, footwear and outdoor gear may be pre-treated with repellent containing permethrin. For the prevention of animals being bitten by a tick, one should use a tick/insect repellent. [en.wikipedia.org]

Because there is no vaccine or specific therapy for Powassan encephalitis, the best way to combat the infection is prevention. Of course, the best means of prevention is protection from tick bite. [pestworld.org]

Centers for Disease Control and Prevention. Preventing tick bites. Available at: https://www.cdc.gov/ticks/avoid/on_people.html. Accessed May 7, 2017. [ahcmedia.com]

الصفحة 1607 - Centers for Disease Control and Prevention: 1994 Revised Classification System for Human Immunodeficiency Virus Infection in Children Less Than 13 Years of Age, MMWR, 43, 1-19, No. ‏ [books.google.com]

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