#17,389
While big-ticket infectious diseases with pandemic potential - like COVID, MERS-CoV, and avian influenza - tend to generate most of the headlines, anyone who spends time outside knows that the number of `lesser' vector-borne diseases continues to rise.
Mosquito and tick-borne diseases - which include dengue, malaria, Zika, Lyme, EEE, WNV, and even heavy hitters like Plague, CCHF, and Lassa fever - can be quite deadly, and even cause large regional epidemics.
Between climate change, and the frequent carriage of these pathogens by travelers (and other animal hosts) around the world, their geographic range, and their impact, continues to grow.
Over the past 15 years we've seen CCHF (Crimean-Congo Hemorrhagic Fever) introduced to Western Europe, both Zika and Chikungunya arrive in the Americas, and Dengue's return to Florida after 70 years.
New tick-borne pathogens continue to emerge (see Virulence: Langya henipavirus - Is it a potential cause for public health concern? and EID Journal: Fatal Case of Heartland Virus Disease Acquired in the Mid-Atlantic Region, United States), and there are likely many more out there yet to be identified.
While not a concern here in the United States, in parts of Europe and much of Russia (see map above), they have a tick-borne disease called TBE, or tick-borne encephalitis. In the ECDC's most recent yearly update (2020), they reported:
Tick-borne encephalitis - Annual Epidemiological Report for 2020
Surveillance report
28 Oct 2022Publication series: Annual Epidemiological Report on Communicable Diseases in EuropeTime period covered: This report is based on data for 2020 retrieved from The European Surveillance System (TESSy) on 25 October 2021.
For 2020, 24 EU/EEA countries reported 3 817 cases of tick-borne encephalitis (TBE), 3 734 (97.8%) of which were confirmed.
The EU/EEA notification rate for 2020 is 0.9 cases per 100 000, which represents a further increase compared with the rate of 0.7 for 2019, and the stable rate of 0.6 from 2016 to 2018.
Cases were more frequently reported among males (male-to-female ratio: 1.5:1) and in the age group 45–64 years.
TBE presents a seasonal pattern. For 2020, 95% of confirmed cases occurred from May to November. July was the month with the highest number of reported cases (n = 1 016).
TBE is cased by a flavivirus (TBEV) which can infect the human nervous system. It is carried by infected ticks (genus Ixodes) or, in rare instances, can be acquired by consuming unpasteurized dairy products from infected goats, sheep, or cows.
The CDC describes the symptoms of TBE as:
Many people infected with tick-borne encephalitis (TBE) virus do not have symptoms. For people with symptoms, the time from tick bite to feeling sick (incubation period) is usually about 7 to 14 days, but can range from about 4 to 28 days.
- Severe disease often occurs including infection of the brain (encephalitis) or the membranes around the brain and spinal cord (meningitis).
- Initial symptoms can include fever, headache, vomiting, and weakness.
- Preventing Tick Bites.A few days later, severe symptoms can develop including confusion, loss of coordination, difficulty speaking, weakness of the arms or legs, and seizures.
- Sometimes initial symptoms last a few days and completely resolve, but then about a week later the more severe symptoms develop (known as “biphasic illness”).
Today, we get a risk assessment from the HAIRS group.
The Human Animal Infections and Risk Surveillance group (HAIRS) is a multi-agency cross-government horizon scanning and risk assessment group, which examines and quantifies the risks of zoonotic diseases in the UK. We've looked at their work a number of times, including:
First the press release, followed by a link to the complete HAIRS report.
A new risk assessment, published by a multi-agency cross-government committee, reports that tick borne encephalitis is now likely to be present in England.
From:UK Health Security Agency Published 5 April 2023
The risk assessment is based on both human cases and the detection of the virus in ticks in several areas of the country. The risk to the general public in the UK remains very low.
There have been 3 cases of probable or confirmed tick-borne encephalitis acquired in England since 2019, including one linked to the Yorkshire area in 2022. This case in 2022 is the first confirmed case in England. The virus has also been detected previously in the Hampshire and Dorset, and Norfolk and Suffolk border areas but may also be present elsewhere as the tick species that carries the virus is widespread in the UK.
The tick-borne encephalitis virus (TBEV) is a virus carried by ticks and is common in many parts of the world, including many countries in Europe. It causes a range of disease, from completely asymptomatic infection, to mild flu-like illness, to severe infection in the central nervous system such as meningitis or encephalitis. Symptoms of this are similar to other causes of meningitis, and can include a high fever with headache, neck stiffness, confusion or reduced consciousness.
Investigations into why the virus has been found in ticks more frequently in recent years are under way, but is likely due to a number of factors.
The risk to the general public in the UK remains very low from TBEV, but the UK Health Security Agency (UKHSA) has recommended changes to testing in hospitals so that any further cases can be detected promptly and will be enhancing surveillance – including asymptomatic surveillance in people in the areas where TBEV has been detected.
Ticks can carry other diseases such as Lyme disease – a bacterial infection which can be treated with antibiotics – so UKHSA is reminding the public to check themselves for ticks after they have been outdoors and remove them promptly and correctly if they are found.
Dr Meera Chand, Deputy Director at UKHSA, said:
Our surveillance suggests that tick-borne encephalitis virus is very uncommon in the UK and that the risk to the general population is very low. Ticks also carry various other infections, including Lyme disease, so take steps to reduce your chances of being bitten when outdoors in areas where ticks thrive, such as moorlands and woodlands, and remember to check for ticks and remove them promptly.
UKHSA carries out surveillance of vector-borne disease in the UK, closely monitoring sentinel animals, tick and mosquito species and their distribution, and the infections that they carry, to understand more about emerging infections in this country.
The public are reminded that they should seek GP advice if they are unwell after a tick bite, and should seek urgent medical attention if they or someone they know:
- has symptoms of meningitis:
- severe headache
- stiff neck
- pain looking at bright lights
- develops neurological symptoms:
- a fit (seizure), if not known to be epileptic
- sudden confusion or change in behaviour
- weakness or loss of movement in arms and legs
- facial dropping, change in vision or slurred speech
UK Health Security Agency press office
HAIRS risk assessment: tick-borne encephalitis
Ref: GOV-14435HTML
Tick-borne encephalitis (TBE) is a viral infection involving the central nervous system in humans.
Until 2019, the causative agent, TBE virus (TBEV), was not considered to occur in the UK.
Since then infected ticks have been found to be present in defined areas of Thetford Forest in the East of England and on the border of Hampshire and Dorset; 2 probable cases of TBEV human infections have been reported in Hampshire, England.
The
This risk assessment was carried out to determine the level of risk to the UK human population.
Anaplasmosis, Babesiosis, The Bourbon virus, The Heartland Virus, Ehrlichiosis, Rickettsia parkeri Rickettsiosis, Rocky Mountain Spotted Fever (RMSF), STARI (Southern Tick-Associated Rash Illness), Tickborne relapsing fever (TBRF), Lyme Disease, Tularemia, and 364D Rickettsiosis.
With spring rapidly approaching, it is worth visiting the following CDC website which offers advice on: Preventing Tick Bites.
