The spread of severe infectious diseases was successfully reduced during the 20th century, but now the dark clouds are gathering. When it comes to bacterial infections, the main problem is the increasing resistance to antibiotics. As for viruses, the major issue consists of the mosquito-borne diseases which are rapidly spreading.
When antibiotics were first introduced they were seen as miracle drugs that could cure previously fatal infections. Precisely because they were so effective, however, they have become too widely applied, not only within healthcare but also in the livestock industry. This has favoured the resistant bacteria, which have been able to multiply at the expense of other, non-resistant bacteria. The situation is at its worst in China and India, but resistance is increasing also in Europe.
“By 2050, it is believed that close to 400,000 patients in Europe every year will die from an infection that could not be treated due to antibiotic resistance”, says Professor of Clinical Bacteriology Kristian Riesbeck.
Furthermore, the resistance will force us to question many surgical procedures. Surgical wounds always involve a risk of infection, especially in hospitals where many difficult bacteria can be found. The advantages will therefore need to be weighed against the disadvantages in a whole new way.
“A C-section to save a mother’s or a child’s life will always be necessary. But will taking a tissue sample to examine the prostate be worth the risk? Or removing a gallstone…perhaps it would be better for the patient to live with recurrent abdominal pain?”, wonders Kristian Riesbeck.
The problem of antibiotic resistence has been known for decades, yet no good alternatives have been developed. This can be explained by both the scientific difficulties and the low profitability, as the patient, hopefully, only uses the medication for a short period of time to combat a bacterial infection, unlike in chronic disease when drugs are taken over many years.
“It costs hundreds of millions of crowns to produce a single antibiotic. Pharmaceutical companies do not believe they will see a return on such an investment from short-term treatments. Furthermore, the bacteria may also become resistant to the new substance within as little as 10–15 years”, says Kristian Riesbeck.
“Insect repellent, covering clothing, mosquito nets, and removing stagnant pools of water can minimise the spread of virusinfection.”
However, there are a few signs of hope. A couple of new or improved vaccines may be available within a few years – a broader vaccine against pneumococcus (the bacteria that causes ear inflammation and pneumonia, sepsis and meningitis), and a vaccine against so-called non-encapsulated Haemophilus influenzae bacteria. In fact, there are also vaccines for animals: in Norway, farmed salmon fry are now vaccinated against bacterial infections.
When it comes to viruses, vaccines were used to successfully eradicate smallpox in the 1970s. Polio remains only in a few countries, and the hope is that also this disease will be eradicated within a few years. There are other dreaded viruses, however. The Ebola virus is one example, which caused over 11,000 deaths in the outbreak that lasted between 2014 and 2016. This outbreak is now over, but instead the Zika virus is on the march.
“Within a few years, the Zika virus has spread from Brazil throughout Latin America and up to Florida. Increasing travel does not only carry air passengers around the world, but also any diseases they may have”, says Professor of Medical Microbiology Stephen Schwartz.
The Zika virus is spread by mosquitoes that thrive in areas close to humans where barrels and other containers of stagnant water can often be found. The majority of the people infected show no or fairly mild symptoms, but pregnant women may experience foetal damage. The foetus develops microcephaly, that is, an abnormally small brain, which usually leads to mental retardation and premature death. Insect repellent, covering clothing, mosquito nets, and removing stagnant pools of water can minimise the spread of infection. However, even if the spread could be stopped, if would not necessarily lead to a sustained improvement.
“The virus was originally found in monkeys. This means that a ‘reservoir’ of the virus can be found in these animals, which can give rise to new outbreaks even if we were to overcome the spread of today”, explains Stefan Schwartz.
Another mosquito-borne disease is chikungunya, currently to be found in Africa, the Americas and Southeast Asia, including outbreaks in southern Europe. The virus causes high fever, muscle aches and joint pain. A third mosquito-borne viral disease that causes pain, fever and rash is dengue. This virus is even more widespread, infecting between 50 and 100 million people every year.
“There is a risk that the spread of these diseases will increase even further, as a warmer climate may cause virus-carrying mosquitoes to expand to new areas. But intensive efforts are also underway to develop vaccines, especially against the Zika and the dengue viruses”, says Stefan Schwartz.
Text: Ingela Björck