Michael Routledge

Michael Routledge

I am Associate Professor of Environmental Toxicology in the School of Medicine, University of Leeds. My research interests are the health effects of mycotoxins and particulate matter.

Location Leeds, UK


  • interesting to hear about this additional mosquito borne parasite@AnibeEtu

  • yes, some occupations (like teachers) are at increased risk of picking up infections

  • yes- and I'd agree with these points

  • Michael Routledge replied to [Learner left FutureLearn]

    good point about the role of poverty in increasing risk

  • Some great comments here. Thanks everyone.

  • Thanks Devon, that's very interesting.

  • you highlight how pesticides/insecticides are important to reduce occurrence. This is a good point. For example, benefits of DDT for this outweigh risks in areas high in malaria

  • that's evolution for you! The viruses evolve to make it possible to enter cells

  • lots of interesting contributions. I see that Dengue fever is cropping up quite often.

  • @GeraldineKershaw
    I think that this term is meant to highlight that there are things that make it difficult for people to change even when lifestyle factors that contribute to disease risk have been identified. By acknowledging that such barriers to change exist, it is possible to start to come up with potential solutions that can help people overcome those...

  • Hi Claudette
    I don't think anyone believes the situation is "right". However, there is a lot of evidence that people with low income, as a group, have poorer health outcomes than more well off people. This is to do with factors such as being able to access a good diet, availability of health care, levels of education and so on. Recognising this is an important...

  • A paper in Nature in 2002 has suggested that acrylamide in food may indeed be formed aa a byproduct of the Maillard reaction. Acrylamide is not present in starchy food that has not been cooked or in food (e.g. potatoes) that have been boiled, showing that the formation of acrylamide is temperature sensitive.

  • I suggest that this sort of question is directed to your doctor who can give more personalised advice.

  • It is important that someone who can't exercise as much does not take in too many calories as they won't be able to burn them off. Im the UK, hospitals employ dieticians to make sure people who are ill get the right balanced diet.

  • I don't think there is any evidence that eating fruits on their own or at the start of a meal do any harm. Large quantities of fruit juice may be a problem because then you get the sugar without the fibre. Whole fruits are better.

  • This is a good question. Less is known about combination effects and of course we can be exposed to mixtures of agents. Some studies carried out on cells in vitro have suggested that some combinations of known toxins can enhance toxicity but the reverse can also be true. Some combinations reduce toxicity. At Leeds we have done some work showing that...

  • Really interesting to hear your comments, thank you. You are clearly aware of the difficulties in an area where people may have little choice about the quality of food they consume.

  • Generally, I like to think a balanced diet is best. Certainly lots of vegetables is likely to be beneficial.

  • It has been concluded that processed meats such as bacon that contain nitrites do increase cancer risk if eaten too often.

  • I agree- it is a minefield! The difficulty with studying human carcinogens is that people's diets tend to be very varied and so identifying exactly what foods increase cancer risk is not easy. I think the evidence on coffee now is that it isn't carcinogenic.

  • These are some good points.

  • don't forget that some toxins occur naturally, although levels of exposure will depend on where you live.

  • I agree with your comment from the individual point of view. We rely on government organisations to protect us against food toxins and hazardous chemicals.

  • Hi Morelia
    I'm glad you already have good understanding. Hopefully, you will learn something new during the course as well.

  • Diabetes is a complex disease. The high blood sugar levels that occur during diabetes have a number of effects including changes that lead to a reduced immune function. This is why wounds heal more slowly in diabetics and some infections can be more common.

  • Hi
    Opsonisation is actually the process by which antibodies bind to bacteria, making them more likely to be ingested by macrophages.

  • Another good point. It is saddening to see both industrial and societal air pollution problems being shifted onto the less developed societies.

  • Good thinking to point out the role of possible confounding factors.

  • A lot of good information here as well.

  • Some interesting information here. The Canadian survey (https://www.ncbi.nlm.nih.gov/pubmed/20973429) included over 5000 samples, so a large study. The presence of BPA in 91% of those samples, with higher levels in children than in adults, is certainly of concern.

  • This has been published in Science of the Total Environment (2017), vol 584-585, pages 631 to 641

  • I would certainly hope that there is no contamination of your locally retailed organic chick peas but when it comes to aflatoxin exposure and cancer, the risk increases with dose and time of exposure. People who are chronically exposed in their diet tend to be eating contaminated food fairly regularly, often because the food (such as peanuts or maize) is a...

  • Yes, Turkey X disease was how aflatoxin toxicity was first identified. As you say, the mystery disease in Turkey's was traced back to contaminated feed from Brazil, in which aflatoxin was identified as being the toxic chemical. This was the start of years of research into the potential effects of aflatoxin on humans.

  • You raise a good point when referring to things such as added salt. Salt and sugar are not considered to be toxic in the amounts used in food but we know there is a lot of evidence that too much salt in the diet increases blood pressure, which is an underlying cause of cerebrovascular and cardiovascular disease. Too much sugar is linked to obesity which is...

  • The melamine scandal in China, where melamine was illegally added to milk powder to boost apparent protein content, leading to several deaths and many affected children is certainly one of the worst recent incidences of food contamination causing illness.

  • You make a good point about naturally occurring toxins in food and the historical issue of food poisoning. The introduction of good hygiene, sanitation and storage practices such as refrigeration have reduced the likelihood of bacterial food poisoning. Regulations and testing also serve to protect the general public, although occasional outbreaks still occur...

  • of course, humans can and do control these things. Many people are worried about pesticides and food additives but we should remember that these are tested and controlled and used at levels thought (from the evidence) to pose very little risk to humans. You are right about being able to prevent most food poisoning by good practices.

  • Autoimmune disease is due to the adaptive immune system attacking our own cells. For example, antibodies being produced that bind to specific molecules on the surface of certain types of cells.

  • Yes. The problem, if you like, with the adaptive response is that it is slow. This is why we do get ill from time to time, because we ave not encountered that pathogen before and it has got passed the innate response. The next time we meet that same pathogen our adaptive system should deal with it more quickly (thanks to the memory cells) and so we won't get...

  • Hi Kumar. I'm afraid that although immunization against TB has been successful in greatly reducing the occurrence of TB, it is not always successful and so TB is not uncommon in some countries, especially in low and middle income countries where 95% of cases occur. So still some way to go for eradication.

  • Glad you find this useful.

  • Hi Edith. I love your metaphor! There certainly is a lot of information out there on this topic.

  • As you point out here Ann, this is something very much in the news at present.

  • There are lots of very good points among the comments on this page. We certainly face a major challenge tackling the problem of antibiotic resistance but at least we can see that resources and thinking are being applied to this challenge.

  • Excellent bit of research there.

  • Well, you could say that a lot of people didn't survive, especially after a wound or surgery. There is no doubt that antibiotics have helped a lot of people over the years and made possible the routine use of surgery.

  • Thanks for your knowledgeable input Dr Nwaelugo. I'm sure it isn't the only simplification we've made in this course!

  • Hi Edith. Thanks for spotting that! I think you must be right about auto-correct. We'll get that changed for the future.

  • Hi
    The other thing about mosquitos is that when they bite they only inject saliva, not any ingested human blood. The malaria parasite is in the saliva but any HIV virus would remain in the mosquito.

  • Hi Carol. Two good questions. Of course not all viruses are the same, but generally speaking, when a virus attacks a cell by binding to molecules on the cell, the virus nucleic acid (DNA or RNA depending on the virus) is injected into the cell. This is then used as a template for making viral proteins (such as those that make up the viral coat) and for...

  • There are some antiviral drugs that can be used to inhibit virus replication, rather than kill viruses. These work by binding to a protein produced by the viral genome that is needed to allow the virus to replicate or spread from one cell to another. But they are only useful once the infection has been diagnosed, rather than for preventing the initial infection.

  • Hi Sarah. Bacteria can be attacked by antibiotics that target different components, such as the cell wall as Janet mentions, but some bacteria target other parts of bacteria. The important thing is that although these may serve the same function as equivalent parts of human cells, they are sufficiently different that bacteria can damage the bacteria but not...

  • You've been doing some good research here Julie.

  • Good points. Basic hygiene measures can be very effective at reducing spread of disease.

  • An excellent point. There is evidence from several studies to show the effectiveness of hand washing to reduce spread of disease.

  • A good point- in the news recently has been the possible increased risk posed to patients undergoing now routine surgical procedures as antibiotic resistance (looked at in this course) increases

  • Pathogenic bacteria that and viruses have evolved alongside animals and have evolved to target particular types of cells, and to promote routes of transmission that help to spread the disease.

  • Don't forget Ebrahim- that also some parasites are multicellular organisms- like the flat worms that cause schistosomiasis.

  • Glad to see you have all got the main differences between bacteria and viruses.

  • It's great to hear about the common diseases in different countries.