Climate change is already having, and will continue to have, a significant impact on global health. This is probably greatest in the poorer rural areas of sub-Saharan Africa. However, wealthier countries, such as the UK, are also likely to be at risk of emerging infectious disease threats as the country warms.
Infections that are mainly found in the tropics are on the move in new areas. Dengue, a mosquito-borne virus, is becoming more common in European countries, particularly in parts of Italy and France. West Nile virus, also spread by mosquitoes, has been common in many US states, with typically more than 1,000 cases reported each year.
Another virus that moves to new places is Crimean-Congo hemorrhagic fever virus (CCHFV), which is transmitted by ticks. Most cases are in Africa or Asia, but cases have been reported in several European countries, including Spain, Turkey, Greece, Russia and Ukraine, with recent media reports warning we could see the virus come to the UK.
So what is CCHFV and should we be concerned? Let’s take a look.
There are approximately 15,000 cases of CCHFV per year worldwide. CCHFV is a serious pathogen – usually between 10-40% of people infected with the virus will die from it.
As the name suggests, CCHFV is part of a group of diseases called viral hemorrhagic fevers. These are described as causing “severe multisystem syndrome”, meaning multiple organ systems in the body are affected. These infections can also be accompanied by heavy bleeding. Other viruses in this group include Ebola, Marburg, dengue and Rift Valley fever virus.
CCHFV is transmitted by a type of tick called the Hyalomma tick. The virus was first identified in the Crimea in 1944 and an outbreak in the Congo in 1956 led to the modern era. To avoid stigma, the names of pathogens are no longer associated with the place where the first known outbreak occurred.
Tick bites are the most common way to get CCHFV. Although transmission has also occurred from needlestick wounds or from infected blood, which means there is some risk for healthcare workers.
But there is little persistent human-to-human transmission, with outbreaks usually relying on the presence of an infected tick. Hyalomma ticks can be found on a variety of animals, including livestock and rabbits. Most animals seem to be able to carry the tick and the virus without getting sick.
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In people infected with CCHFV, symptoms usually begin with fever, muscle aches, or dizziness and can rapidly progress within days to kidney failure or sudden liver failure.
CCHFV is recognized by the World Health Organization (WHO) as a virus for which limited research has been conducted but where the pathogen is considered to be a major threat.
There is no vaccine or proven antiviral treatment. However, ribavirin, a drug used to treat other viruses such as hepatitis C, has shown some promise.
Should we be worried?
Within the UK, there have so far been only a small number of imported cases of people contracting the virus while traveling in high-risk areas.
There is ongoing research and monitoring in areas such as marshland, where ticks and mosquitoes are caught and studied to see if there are any new or developing threats. The Hyalomma label is not currently in place in the UK, so the risk is very low for now.
Yet there are many other types of ticks in the UK, including those responsible for causing Lyme disease, which are usually found on vegetation. They can’t walk or fly, so public health tips to protect yourself from tick bites include avoiding brushing against vegetation while hiking, performing regular tick checks, and using repellents.
In areas where CCHFV is at higher risk, such as during or after an outbreak, hygienic storage of meat is considered important and animal movement restrictions may be imposed.
There is concern from the WHO and other health experts about the global spread of this Hyalomma mite. The wide range of animals that the tick is found on means that it has the potential to become endemic in new communities. The tick has also been detected in long-distance migratory birds and was found in 2018 in Sweden for the first time.
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Viral hemorrhagic fevers such as CCHFV can cause severe illness and death in some people who become infected. Local outbreaks can also have other consequences for poor farming communities, such as the slaughter of their cattle and the subsequent loss of business.
It is unlikely that there will be a significant number of cases of CCHFV in the UK any time soon. However, as globalization increases and climate change continues to alter disease patterns, it is likely that the virus could be a persistent threat in the future.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Michael Head has previously received grants from the Bill & Melinda Gates Foundation and the UK Department for International Development.
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