The new study analyses data from school aged children in Tanzania infected with the most common forms of worms. It was found that infection by one parasitic species actually changes the risk of catching another, over and above other risk factors.
The study is the first to look at the significance of infection with one disease as a risk for further infections (i.e. co-infection). The findings could help us better understand the importance of co-infection as a risk, and could help inform disease control strategies.
Traditionally, co-infection, where the person or population of people has more than one parasite species in it, has been seen as a result of other risks. For example, if people in a population have two different parasites more often than expected by chance, then it is often thought that these two parasites must have been picked up at the same time because of where they are in the environment (co-exposure) and that the place the person lives or plays therefore is the cause of this co-infection (in other words a person's environment would be the risk factor).
Dr Joanne Lello, Cardiff University School of Biosciences and lead author on the study said: "Infectious diseases are among the most important causes of childhood mortality and morbidity in the developing world. Understanding what drives an individual's infections is essential if effective disease-control strategies are to be developed. We know there are many possible risk factors associated with an individual's infections, including their physical environment, genetics, behaviour and demographic factors, but a comparatively understudied risk factor for infection with one organism is co-infection with a second species."
By studying the associations between the four most prevalent infections among school-aged children in Tanzania - Ascaris lumbricoides, Trichuris trichiura, hookworm and self-reported fever - Dr Lello and colleagues (from the Universities of Bristol and Basel (Switzerland) and from the Ministry of Health in Tanzania), found that co-infection cannot be explained away as a simple coincidence that is due, for example by co-exposure in the environment.
They found that co-infection is itself a very important risk factor, and sometimes more important than any of the other risks considered, such as a child's living conditions, behaviour and sex. However, the risk does not always increase. They also find that infection with one parasite species can sometimes be associated with a lower risk of infection with a second parasite species.
Explaining the significance of these findings, Dr Lello, said: "We were able to include in our statistical model many different things which have been identified as risks before, for example a child's living conditions, behaviour, sex and so on. As such we could tell that the co-infections were not just caused by these 'other' risks and importantly we could also tell how much difference every risk made compared to one another. This showed us that co-infection was important for all the diseases we looked at and often it was more important than most of these 'other' risks.
"When medics and government design programmes to control diseases they use their knowledge of what things change the probability of becoming infected, called risk factors. If we miss out important risk factors then control programmes are unlikely to work effectively and resources can be wasted targeting the wrong things. Knowing that co-infection is a major risk factor is therefore really important and our study demonstrates this for the first time.
"Although our study was conducted on children in Tanzania, co-infection with different parasites occurs everywhere and so the principle that one parasite can change the probability of being infected with another has wide implications."
Cardiff University: http://www.cardiff.ac.uk
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
If we want to understand whats happening in the brain when people hear voices, we first need to understand what happens during ordinary inner speechHearing voices: whats your experience when reading?
Seals and sea lions may have brought a form of tuberculosis to the Americas, centuries before the Spanish did so
More people with non-fatal conditions are travelling to assisted dying clinics in Switzerland
We’re all born to adore ourselves, but not all of us grow up
Rumours of dubious treatments are spreading on social media in West Africa, while fishy Ebola treatments are being peddled to anxious US citizens
The type of Ebola erupting in West Africa is closely related to one found 2,500 miles away — the distance between Boston and San Francisco. How did the virus spread so far without anyone noticing?
The tendency of Clostridium novyi to kill mammal cells has been used to shrink tumours in dogs and people, so the bacteria could help fight some cancers
The Burns Collection consists of human cadavers from the early 1800s that were anatomically dissected and preserved to teach anatomy and surgery to medical students. For the first time this portion of the collection is on display to the public as a part of traveling exhibit "Mummies of the World: The Exhibition."
Author Adam Rogers says there are lots of myths about what causes hangovers. His new book, Proof: The Science of Booze, explores these and other scientific mysteries of alcohol's effect on the body.
An experimental vaccine being developed by U.S. government scientists to prevent the painful mosquito-borne viral disease chikungunya has shown promise in its first human trials but remains years away from approval for widespread use.