Crimean-Congo haemorrhagic fever (CCHF)

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According to the World Health Organization (WHO), rising temperatures in Europe have also raised fears of spread of viruses generally not found in colder climates namely includes Crimean-Congo haemorrhagic fever (CCHF), an infection spread by ticks that has a high fatality rate.
  • In June 2023, a person got infected from the Crimean-Congo haemorrhagic fever in Gujarat whose vaccine is still not made.
  • The CCHF is endemic to Africa, the Balkan countries, Middle East, and parts of Asia.
  • The first fatality from the disease in Europe was in Spain, in 2016.
  • Scientists are now warning that CCHF, which can kill between 10% and 40% of patients, is spreading northward and westward in Europe.
About Crimean-Congo haemorrhagic fever (CCHF):
  • Crimean-Congo haemorrhagic fever (CCHF) is a viral haemorrhagic fever usually transmitted by ticks.
  • It can also be contracted through contact with viraemic animal tissues (animal tissue where the virus has entered the bloodstream) during and immediately post-slaughter of animals.
  • Vector of the spread: ‘Ticks’, especially those of the genus, Hyalomma, are both a reservoir and a vector for the CCHF virus.
  • Numerous wild and domestic animals, such as cattle, goats, sheep and hares, serve as amplifying hosts for the virus.
  • Transmission to humans occurs through contact with infected ticks or animal blood.
  • CCHF outbreaks constitute a threat to public health services as the virus can lead to epidemics, has a high case fatality ratio (10–40%), potentially results in hospital and health facility outbreaks, and is difficult to prevent and treat
  • Symptoms:
  • CCHF symptoms include fever, muscle ache, dizziness, neck pain, backache, headache, sore eyes and sensitivity to light.
  • There may be nausea, vomiting, diarrhoea, abdominal pain and sore throat early on, followed by sharp mood swings and confusion.
  • After 2–4 days the agitation may be replaced by sleepiness, depression and lassitude.
  • Treatment:
  • There is no vaccine for the virus in either humans or animals, and treatment generally consists of managing symptoms.
According to the WHO, “the antiviral drug ribavirin has been used to treat CCHF infection with apparent benefit.”
How Climate Change contribute to spread of Viruses?
  • As temperature patterns are disrupted, pathogens are thriving in geographies that traditionally had a climate hostile to them.
  • Climate change contributes to the spread of diseases in multiple ways, including:
  • Warmer temperatures expanding the habitat of ticks and other insects and giving them more time to reproduce;
  • The habitat offered by water undergoing changes; and
  • Animals moving to newer areas and people coming into contact with them.
Effects of rising temperature on Microorganism:
  • According to a study, an increase in temperature will increase enzyme activity. But if temperatures get too high, enzyme activity will reduce, and the protein (the enzyme) will denature.
  • On the other hand, lowering temperature will decrease enzyme activity.
  • In general, the higher the temperature, the more easily microorganisms can grow up to a certain point.
  • Very high and low temperatures both obstruct the enzyme processes microorganisms depend on to survive.
Survival of Microorganism in high Temperature:
  • Generally, microorganisms with an optimal growth temperature (OGT) between 60 and 80°C are designated as thermophiles, whereas those growing optimally at temperatures of >80°C are referred to as hyperthermophiles, which are found in the three domains of life, archaea, bacteria, and eukarya, but the majority are archaea and bacteria.
  • Environmental changes such as temperature shifts induce genomic evolution, which in turn provides the bacteria with thermal-tolerant abilities to survive under high temperatures.
  • Such evolutionary changes could be achieved through horizontal gene transfer (HGT), gene loss, or gene mutations.

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