Posts Tagged Hand Washing
1928 was a happy year for humanity as this was the year that a nondescript mould called Penicillium notatum was found to have antibacterial properties. This mould would prove to be the first in a long line of what we now know as antibiotics. Antibiotics are a group of drugs that kill bacteria for us either by interfering with their cell wall, mucking up their DNA or messing with their metabolic processes so they cease to function. Unfortunately they do not affect viruses.
Before the discovery of antibiotics people died from all sorts of minor complaints such as small infected skin wounds (before penicillin1 in 9 skin infections killed people), mild burn infections, tooth abscesses and infected insect stings. Unfortunately, according to a recently published World Health Organisation report (http://www.who.int/drugresistance/documents/surveillancereport/en/), that time could be returning as more and more bacteria are laughing in the face of the antibiotics we use.
The natural world uses a marvellous tool to adapt to changing circumstances. It is called natural selection and it is based on genetic diversity. This means that when a disease comes along it rarely kills everyone. Some people will be naturally resistant to it. They will survive and breed and, before you know it, most people will be resistant and the disease will no longer kill people. Unfortunately the same is true for bacteria and antibiotics. In any given bacterial population some bacteria will be resistant to a given antibiotic. Using that antibiotic will kill off the sensitive bacteria, leaving the resistant ones behind to proliferate. This activity can be accelerated by increasing the use of antibiotics, especially when they are prescribed for conditions that cannot be resolved by antibiotic use, such as the common cold or flu, both of which are viruses and completely unaffected by antibiotics.
If you are prescribed antibiotics, to delay the onset of resistance appearing, it is vital to take your full dose and complete the prescription, even if you feel better ahead of time. Otherwise you have not killed the bacteria but only wounded them, allowing them the opportunity to strike back bigger and better than before.
It is also important to practice effective preventative medicine to minimise the number of times that antibiotics are needed. An example of this is gonorrhoea. More than one million people are infected with gonorrhoea around the world every day. Resistance of this bacterium to all antibiotics is becoming more and more common. Prevention is simple and obvious. All it requires is a condom. Preventative measures for other diseases can include vaccination, washing your hands with soap and water, wearing your protective gear at work, not allowing your pets to stick their tongues down your throat, washing your hands with soap and water, observing good hygiene when preparing food, washing your hands with soap and water, and sticking with bottled water if you are uncertain of the quality of the water supply. Oh, and did I mention washing your hands with soap and water?
Dr. F. Bunny
MERS (Middle East Respiratory Syndrome) is the latest disease in nature’s little bag of tricks, which could turn into the next pandemic and solve our population issues for us. It is closely related to SARS (Severe Acute Respiratory Syndrome), both belonging to the same virus family. But, while SARS appeared in Asia, MERS first popped up in Saudi Arabia in 2012. Since then all cases have been seen either in the Middle East or in people who have travelled to the Middle East. As of June 2014 we have had 697 cases of which 210 people have died. As usual symptoms have been flu-like.
This is quite a high case fatality rate but, like bird flu, the virus has not raced around the world killing a third of the world’s population because it is not easily transferred from person to person, yet.
Any time one of these new diseases pops up it requires quite a bit of detective work to try and determine where it came from and how it works. It will probably come as no surprise that bats are once again implicated, the virus having been found in Egyptian tomb bats, a name guaranteed to generate sympathy with a nervous public.
Intriguingly the virus has also been found in camels, a situation which has some similarities with Hendra virus in Australia. Hendra virus lives happily in bats, infects horses (and kills them) and then spreads from horses to humans. However, as yet, there are no recorded cases of MERS causing disease in camels (although a number of camels have died in the UAE recently of undetermined cause, so this situation may change) and we have only recently seen the first confirmed case of a human catching the disease from a camel. Most of the other cases have been in people who have had very close contact with other sufferers. Where they caught it originally is still open to speculation.
It makes me think that the practice of veterinary medicine may be more dangerous than first thought. While we are all aware of the wonderful things we can catch from our primate neighbours no one really believed there was anything worth catching from our more distant cousins, like horses. Twenty years ago you would not have thought twice about examining a snuffly horse. Two years ago you would not have thought twice about examining a camel.
Australia has the largest feral camel population in the world, but no human cases of MERS. Preliminary testing of 25 camels has failed to find any evidence of MERS, implying that the Middle East camels may have been infected from the tomb bats or that the virus appeared in Middle East camels after the Australian population was established.
The upshot of all this is that we have absolutely no idea where the next fun plague might be coming from. As I get older and more paranoid I am becoming increasingly more nervous about travelling on crowded trains, planes and buses, full of sneezing and coughing people. And I am starting to think that sport is much more enjoyable when viewed from the comfort of my living room than from one of those packed sporting stadiums. I can see the day coming when I refuse to venture outside without my biohazard suit on.
Paranoia aside, most viruses are transferred between us via the things we touch, such as door handles, coffee cups, pens, etc. The best way to prevent this is by washing your hands frequently, with soap and water. To do it properly, sing the Happy Birthday song through twice while you are soaping up your hands. Oh, and don’t kiss bats, camels or any other non-human life forms. And maybe not even the human life forms.
Dr. F. Bunny
Zoos exist to save people money spent travelling to exotic places to see animals in the wild. By bringing a large number of species together in a small space people get a snapshot of the world’s different biomes. Pity the archaeologists of the future digging through the remains of Melbourne, Los Angeles and London, wondering how elephants, tigers and monkeys could have been native to all three cities.
While it’s certainly “nice” to see polar bears in Melbourne, they don’t appreciate the summer heat any more than the gorillas in Toronto enjoy the snow. This mixing and matching produces all sorts of husbandry and dietary problems, which are handled with varying degrees of success. It also creates novel disease issues. This was highlighted recently by the deaths of four polar bears in a German zoo (Greenwood et al 2012). They died of a herpesvirus infection contracted from the zoo’s zebras. The herpesvirus was perfectly well adapted to the zebras and caused them no problems but, when it got into a naïve, non-adapted polar bear, fatal illness was the result.
Herpesviruses seem particularly good at this sort of thing. African elephants carry a herpesvirus that is fatal to Asian elephants. Wildebeest carry a herpesvirus that kills other species of hoofstock. Squirrel monkey herpes kills owl monkeys. A herpesvirus carried by South American conures kills African and Australian parrots. SIV, a relative of HIV (and not a herpesvirus) carried by African monkeys, kills Asian macaques. Normally this would not be a problem as these animals, and their bugs, would not come in contact with each other. However, this mixing of animals from different areas, which gives adapted viruses and bacteria access to non-adapted hosts, is occurring more and more.
Not only is this a problem in zoos but it is happening in the big wide world too. As we clear more and more habitat we come into contact with new species and new disease agents. Feral species, which have made their way into new habitats because of our deliberate or accidental influence, bring their bugs with them too. Species that previously had no connection with each other are suddenly brought into close proximity. Hence, the transmission of Hendra virus from bats to horses, Nipah virus from bats to pigs, toxoplasmosis from feral cats to marsupials and otters, monkeypox from Gambian giant rats and prairie dogs to humans, and chytridiomycosis from African clawed frogs to the amphibians of the world.
At least, when animals are concerned, some of these diseases can be confined to farms or contained by quarantine measures. These are, however, not always as effective as we would like as seen by the introduction of foot and mouth disease to Great Britain, equine influenza to Australia, and psittacine pox to New Zealand. These diseases were eradicated at great expense and effort.
Unfortunately people don’t go through quarantine when they travel, allowing for extremely rapid dissemination of diseases. Just look at how quickly SARS spread from South East Asia in November 2002 to Canada by April 2003. It is estimated that a flu outbreak in the northern hemisphere will reach Australia in four to eight weeks. While we impose travel restrictions on animals to safeguard our pets and agriculture we certainly don’t want to inconvenience ourselves by impeding our own travel, even though the consequences are potentially far more catastrophic. While globalization has facilitated trade, democracy, entertainment, and the dissemination of information, it has also greatly enhanced our ability to spread disease. Unfortunately the science of predicting what the next possible pandemic will be and where it will come from is at a similar stage as the science that predicts earthquakes and volcanic eruptions i.e. we have absolutely no idea. For the moment all we can do is react and hope that will be enough.
And don’t forget to keep washing those hands.
Dr. F. Bunny
Greenwood, A.D., K. Tsangaras, S.Y.W. Ho, C.A. Szentiks, V.M. Nikolin, G. Ma, A. Damiani, M.L. East, A. Lawrenz, H. Hofer, and N. Osterrieder. 2012. A potentially fatal mix of herpes in zoos. Current Biology http://dx.doi.org/10.1016/j.cub.2012.07.035.
This time we are talking about flu, not cute primates with upturned noses. It’s that time of year again, at least in the southern hemisphere, and there are a few simple precautions you can take to help you through.
As previously mentioned in Vaccination 101 there are lots of different flu viruses that, unlike leopards, do change their spots regularly. This makes it impossible to control all of them with a single vaccine. However, each year the World Health Organisation recommends which three flu strains to stick in the current year’s vaccine, and I certainly recommend getting it. It stops you feeling miserable and may even save your life. If work places displayed any common sense they would vaccinate all their employees for free. The savings in sick leave taken would surely compensate for the cost of the vaccination. But you don’t have to be vaccinated if you don’t want to. Your plane won’t be shot down, you won’t be rounded up and forcibly jabbed and you won’t be stopped from travelling and infecting other people.
The trouble with flu viruses is they get around, fast. It is estimated that, if a new flu strain emerged in Europe, it would hit Australia in four to eight weeks, despite our relative isolation from the rest of the world. While the H1N1 flu turned out to be relatively benign (only killing 0.03% of the people it infected) it did hit 70 million people. The H5N1 flu has killed 60% of its victims but has only infected 600 people (http://www.who.int/influenza/human_animal_interface/EN_GIP_20120607CumulativeNumberH5N1cases.pdf). Because it targets receptors in the lower respiratory tract it is harder to spread but more deadly. Unfortunately it would not take many mutations for H5N1 to start spreading like H1N1. Then we’ll see who thinks vaccination is a waste of time.
Apart from receiving a needle the best form of prevention has been discussed previously. Boring though it sounds, here it is: wash your hands, with soap, regularly. Flu viruses survive in the air for up to an hour, on hands for five minutes, on soft cushions for 20 minutes and on hard surfaces for 24 hours. So, every time your flu sufferer touches anything they will also be applying a liberal dose of virus. When you then touch the same surface, or shake that hand, you also receive a helping of virus. Alternatively use alcohol wipes on your hands. Monk wasn’t nearly as crazy as he was made out to be in his TV series.
Depending on your level of paranoia you could also avoid crowded areas such as public transport, classrooms and offices, as these all have lots of possibly contagious people and minimal air movement. Stay away from small children and keep at least two metres between yourself and your infected colleagues.
Unfortunately the time when people are most contagious and shedding the most virus is a day or two before they develop symptoms. They will remain contagious for about another four days after symptoms start, so do yourselves, and the rest of the world, a favour. Stay home and finish that book, win that Playstation Stanley Cup or watch all those episodes of Get Smart you always promised yourself you would. And, in the words of Sergeant Phil Esterhaus from Hillstreet Blues, “Let’s be careful out there.”
Dr. F. Bunny
And if you’re still not convinced see: http://www.sbs.com.au/news/article/1667868/Deadly-flu-season-hits-Australia-hard
Everywhere we look we are beset by the scourge of Salmonella. It turns up in bird feeders (Alley et al 2002), home aquariums (Levings et al 2006), and most recently in playground sand (Staff et al 2012). While Salmonella infections have been commonly associated with reptiles all animals should be considered carriers of Salmonella. I recall a case of diarrhoea in a kangaroo joey that was being hand raised. The carer, concerned for his welfare, took him to bed with her each night to keep him warm. Oddly enough the carer then developed the same diarrhoea as the kangaroo.
The US reports 40,000 human cases of salmonellosis each year (http://www.cdc.gov/nczved/divisions/dfbmd/diseases/salmonellosis/#how_common). Who knows how many unknown cases of salmonellosis there are? After all how many times have you submitted your faeces for bacterial culture when you had diarrhoea?
The thing is that most of these cases can be easily prevented. Salmonella really doesn’t like soap. With a bit of common sense (stop sleeping with your patients) and more attention to personal hygiene most of us should remain diarrhoea free. All it requires is to wash your hands with soap and water for at least 20 seconds (that’s equivalent to singing the Happy Birthday song twice) each time you handle an animal, clean the cat box, fish tank, etc and certainly before eating, preparing food or smoking. Actually don’t worry about washing before smoking. If, in this day and age, you’re still stupid enough to be smoking you probably deserve everything you get. Consult http://www.cdc.gov/features/handwashing/ for those who are hand washing challenged.
Dr. F. Bunny
Alley, M.R., J.H. Connolly, S.G. Fenwick, G.F. Mackereth, M.J. Leyland, L.E. Rogers, M. Haycock, C. Nicol, and C.E. Reed. 2002. An epidemic of salmonellosis caused by Salmonella Typhimurium DT160 in wild birds and humans in New Zealand. New Zealand Veterinary Journal 50:170-176.
Levings, R.S., D. Lightfoot, R.M. Hall, and S.P. Djordjevic. 2006. Aquariums as reservoirs for multidrug-resistant Salmonella paratyphi B. Emerging Infectious Diseases 12:507-510.
Staff, M., J. Musto, G. Hogg, M. Janssen, and K. Rose. 2012. Salmonellosis outbreak traced to playground sand, Australia, 2007-2009. Emerging Infectious Diseases 18:1159-1161.