1

Cells, Microbes & Viruses / Could a virus or bacterium survive inside a rock?

« on: 23/03/2018 04:12:49 »

So, some viruses (and some bacterial spores) are known to survive for long periods in the environment and be resistant to the elements. Would it be possible for a particularly hardy pathogen to land on some sediment, become incorporated into the rock as the sediment is compacted, spent thousands of years protected inside this rock in a dormant form, and then finally be released into the environment when the rock breaks apart (erodes, falls off the side of a cliff, earthquake etc.) and go on to infect a new host?

2

Plant Sciences, Zoology & Evolution / Re: What is the plumbing associated with feline spraying?

« on: 21/03/2018 00:25:06 »

Oh my goodness; I don't suppose you have a video of that too do you, @PmbPhy ?!

Yet another excuse to spend hours watching YouTube cat videos...

3

Plant Sciences, Zoology & Evolution / Re: What is the plumbing associated with feline spraying?

« on: 20/03/2018 11:21:29 »

Cats are extremely malleable. Their body faces forwards while their back end does a U-turn.

4

Plant Sciences, Zoology & Evolution / Re: What is the plumbing associated with feline spraying?

« on: 20/03/2018 10:54:21 »

Like evan_au has pointed out, male cats have a penis that faces directly backwards, so where you see the urine stream coming from in the video, is exactly where the penis is.

I found this rather "charming" photo of a hairless cat, perfect for demonstration purposes.

https://i.pinimg.com/originals/de/dc/af/dedcaff1708c81b4ee7ec1c0c5cc01b9.jpg

5

Plant Sciences, Zoology & Evolution / Re: Why vaccinate a dog every year?

« on: 20/03/2018 03:12:02 »

(Do I really want to talk about vaccines over the internet?...)




Hi itadiki,

I'm not sure where in the world you are, so please keep in mind that it is really difficult for me to give an answer that applies across all countries. If you want an accurate answer for your particular situation and location, it would be best that you speak to your local vet directly.

The answer will vary depending on what diseases are prevalent (common) where you live (or travel to), and what registered vaccines are available to veterinarians in your country. Even within a given country, there may be variation in vaccination recommendations since some diseases occur more commonly in some areas than others, depending on factors such as geographical variation, urban vs. farm environment, and socioeconomics.

For example, I live in a part of Australia that is urban, and the main infectious diseases of concern in dogs that can be vaccinated for are parvovirus ("Parvo" gastroenteritis), adenovirus ("hepatitis"), distemper virus ("distemper"), parainfluenza virus ("kennel cough" or "canine cough" complex) and Bordetella bronchiseptica bacteria ("kennel cough" or "canine cough" complex). So these are the diseases that our local recommendations are based on. Some more rural and farming areas may also have increased risk of Leptospira bacterial infection (leptospirosis), so vaccination recommendations will reflect that. I’m less familiar with rabiesvirus recommendations, as we don’t have rabies in Australia, but it is another common routine vaccination performed in other countries.

So… The easy part of the answer is that the available “kennel cough” or “canine cough” vaccines all have a short duration of immunity, of approximately one year, so that is why that part of the vaccination program is always recommended as a yearly booster. Dogs that lapse on these boosters are at risk of becoming ill themselves, and shedding disease to other dogs.

The other part of the routine vaccination protocol (the “C3” – parvovirus, adenovirus, distempervirus) has been subject to some variation in vaccination recommendations in recent years, with the development of newer vaccine products; and more recently, a growing public phobia of vaccines. Traditionally, the standard recommendation was an annual vaccination booster for any of the available brands of C3 vaccines. However, there are CERTAIN vaccines for C3 now available and registered for a three-yearly vaccination program. The key word here is “registered”, which means that the product has been clinically tested to scientifically demonstrate both safety AND effectiveness (efficacy) when used according to the recommendation on the label. It also means that the manufacturer of the vaccine will accept liability in the case that the vaccine did not provide adequate protection. Using a registered 1-year vaccine product as a three-yearly vaccine is called “off-label” or “extra-label” and does not carry the assurance that the vaccine will actually be protective over that whole 3-year period. It is best to discuss with your vet about which vaccine options are available to you in your area.

All of the three viruses that the C3 vaccine protects against are deadly, extremely difficult and costly ($1000s) to treat, with no guaranteed survival even with intensive treatment, and often result in heartbreak for the family of the pet, and for the vet who has to watch an animal die despite their best attempts to save it. This is why you will find that all vets recommend vaccination against these viruses. It isn’t to make money, as the internet will have you believe. Vaccines cost owners less than 5% of the cost to treat parvovirus, so it would be a pretty stupid way to try to get rich. You’ll find that vets would just rather not have to see another sick dog die from such horrible, but preventable diseases.

In the case of an owner who is extremely concerned of vaccinating their dog, or a (rare) dog that has previously had a vaccine reaction, vaccination titre tests are also now available. These test the level of antibody in the blood stream, to help predict if the dog is currently protected by a previous vaccine, or not. Unfortunately, there are no scientific studies to date that indicate what level of titre is required to indicate that a dog is protected (immune). So, you will get a result, but that number won’t tell you what will happen if the dog is exposed to the virus. The other downside is that these tests are relatively expensive to run and may not be available in some locations. But it is certainly something you can discuss with your vet, if you are not concerned about paying the extra for testing.

The prevalence of disease may also affect vaccination recommendations in a given location, since the risk of exposure and infection is higher in some areas that in others. For example, some towns are known to be “hot spots” for parvovirus, due to low vaccination rates, and a high number of unvaccinated dogs mixing. Disease outbreaks are another situation when the risk of infection is higher than average. Consequently, the recommended frequency in “Town A” and surrounds may be higher than in “Town G” and “Town M”.

Herd immunity. This is basically when a certain frequency of immunity is required in a population to provide protection across all members of that population. The typical frequency required for this is usually high (>70%) but even higher for diseases that are highly pathogenic or highly contagious. When the level of vaccination drops in the community, it puts the entire population at risk of outbreaks and results in large amounts of virus/bacteria in the environment. Some members of the population cannot be vaccinated due to genuine reasons such as age (eg. newborns, geriatric), or problems with the immune system, and they rely on those healthy enough to do their bit for the team. This goes for both dogs and humans.

Human health. Some health recommendations for pets take also into account the risk of disease to humans. Zoonotic diseases are those that can transmit from animals to humans and cause disease. The best example of this would be rabies, which is deadly in both animals and people, and is transmitted through bites and saliva. My understanding is that it is legally required to vaccinate dogs and cats yearly against rabies virus in some countries where it is endemic (widespread). This is to not only protect the pet from life-threatening disease, but to protect humans who would be at risk of death if the pet becomes infected. Because, legally, human health often has to take precedence over animal health, an unvaccinated pet that bites a human may be required by law to be euthanised and their brain submitted to a lab for rabies testing. This is a very unfortunate, and sadly not uncommon, consequence for both the pet and the owner who has chosen not to follow vaccination recommendations.

6

Plant Sciences, Zoology & Evolution / Re: Do dogs get synaesthesia?

« on: 24/09/2017 13:17:24 »

I agree with Chris. You can't ask a dog, so it would be pretty hard to test your hypothesis. Although, it might be possible to make some indirect implications by comparing dog brain activities patterns to those of humans, using imaging techniques.

7

Physiology & Medicine / Re: Why do we snore when we’re asleep but not awake?

« on: 24/09/2017 11:32:59 »

Some people seem to snore when they are awake. I have sat next to them on the train...

8

Plant Sciences, Zoology & Evolution / Re: Can Indian and African elephants interbreed?

« on: 27/08/2017 11:07:01 »

I'm a bit surprised that those two species have been able to interbreed at all (according to that reference) given the extensive geographical isolation and taxonomical difference. They are not even the same genus.

I'm not sure if there are any specific genetic factors that would make their offspring incompatible with life. However, so much has to "go right" for an elephant between conception and adulthood for it to succeed, that I'd think that any suboptimal physiological factors would surely have to disadvantage such a hybrid (near enough is probably not good enough). For example, I would wonder about the effects of:
- different foetal size vs. placental blood supply
- different foetal energetic/nutritional requirements vs. maternal requirements and intake
- different foeto-pelvic proportion
- slightly different gestational period
- different composition and volume of the milk and colostrum
- different growth rates and possible increased susceptibility to disease (eg. elephant endotheliotropic herpesvirus)
- different height ratio between the calf and the mother's teats
- social factors (eg. maternal acceptance, acceptance into the herd)
- dental malocclusion from overcrowding
- skeletal abnormalities combined with an enormous body weight

9

Plant Sciences, Zoology & Evolution / Re: Can a big dog breed with a small dog?

« on: 27/08/2017 07:11:30 »

This happens all the time, regardless of breed genetics and physical attributes, and in both directions (large female to small male, large male to small female). As SeanB mentioned, it's generally better for the female to be the larger/same size in the pair, to reduce the risk of life-threatening birthing difficulties that require C-sections (as the pups become too large to pass through the pelvic canal, as in natural birth).

Love (or rather, hormones) do find a way.

10

Cells, Microbes & Viruses / Re: Are any viral infections good for our health?

« on: 19/07/2017 13:02:45 »

Do viruses exist to infect living things, or do living things exist to facilitate the existence of viruses? Are we all just the machinery for viral reproduction?

Philosophical question...

11

Physiology & Medicine / Re: The more you eat, the hungrier you feel - do you agree?

« on: 06/07/2017 05:02:20 »

I find it pretty challenging to sort though the literature on nutrition, but here is a fairly comprehensive review on the role of dietary protein in satiety and weight loss:
Westerterp-Plantenga MS, Lemmens SG and Westerterp KR (2012). Dietary protein – its role in satiety, energetics, weight loss and health. British Journal of Nutrition; 108, S105–S112.
https://www-cambridge-org.ezp.lib.unimelb.edu.au/core/services/aop-cambridge-core/content/view/CCA49F7254E34FF25FD08A78A05DECD7/S0007114512002589a.pdf/dietary_protein_its_role_in_satiety_energetics_weight_loss_and_health.pdf

Another interesting paper on pica and cissa:
Touyz LZG, Ferrari CIC (2016) Odd Cravings, Appetite, Hunger, and Thirst. Int J Dent Oral Health; 2(4).
https://www.sciforschenonline.org/journals/dentistry/article-data/IJDOH-2-189/IJDOH-2-189.pdf

12

Physiology & Medicine / Re: The more you eat, the hungrier you feel - do you agree?

« on: 05/07/2017 15:52:54 »

I have two working theories on this: the first slightly more established, the second more of a "watch this space". Here goes:

1) Hunger isn't as simple as a measure of the volume of food consumed, but also of the quantity of particular nutrients. I strongly subscribe to the idea that the body seeks to obtain any nutrients that it is deficient in, although sometimes it is misguided on what it must eat to obtain said nutrient. An example of this is when severe nutritional deficiencies can lead to "pica" (the abnormal craving and consumption of non-food items). It appears that when the deficiency of nutrient is severe enough, the body is willing to have a go at eating ANYTHING to try an obtain that nutrient. Similarly, pregnant females are frequently reported to crave very unusual food items during pregnancy; perhaps due to extremely high nutrient requirements for both mother and foetus.

In Western society, there are plenty of easy-access food products that border on the definition of "non-food items" and are quite low in their nutrient content (other than fat, salt and sugar). Therefore, if a large part of your diet comprises of such low nutrient items, you are going to end up deficient in essential nutrients such as proteins and vitamins. In order for your body to then find those nutrients, you are going to have to eat even more food, until the required nutrients are obtained. If you eat highly nutritious foods (eg. vegetables and whole foods), you may be able to correct the nutrient deficit while ingesting a relatively low number of calories. But if you eat nothing but potato chips, it is going to take a really large amount of chips, along with a REALLY large number of calories to fulfil your nutrient requirements.

An animal nutritionist told me that different animals have different core nutrients that drive hunger and satiety. For example, grazing herbivores often need to eat a certain amount of fibre before they feel full and stop eating, while primates need to eat a certain amount of protein before they feel full. For either group, if they don't get enough of that nutrient, they will likely continue eating and be at risk of obesity. This is probably a gross oversimplification. But you mentioned that you were eating more protein at the start of the day, and have possibly replaced a few high-energy, low-nutrient foods, with a variety of low energy, high nutrient foods. Which may be part of the reason that your hunger (or desire for nutrients) is reduced for the rest of the day.

2) The second theory revolves around the resident gut bacteria (the “gut microbiota” or “gut microbiome”), possibly the most underrated organ of the human body, consisting of bacteria, protozoa, and even worms. The importance of the gut microbiome is more obvious in some species than others. Specialist herbivore species (eg. horses, rabbits, guinea pigs, ruminants, koalas, kangaroos) may very well die from severe disruption of the gut microbiome (dysbiosis) through the use of certain oral antibiotics. The role of the microbiome becomes less obvious in omnivores and carnivores, although, I believe is still important. Recently, I personally experienced severe illness and inability to digest any food other than dairy products after a course of antibiotics, which was a dreadful experience.

The types and proportions of organisms that make up an individual’s gut microbiome can be dependent on what species you are, but also by diet (more so in some species that others). For example, the gut bacteria in a baby mammal drinking milk can be vastly different to the bacteria in an adult of the same species, who consumes mainly solid food. By feeding the bacterial population a certain type of food over a long period, certain species of bacteria that thrive on that food are likely to do better that other species that prefer a different type of food substrate. Suddenly changing the diet from Food A to Food B, is potentially going to 1) upset the population of bacteria currently in the gut that has adapted to thriving on Food A, and 2) result in less efficient digestion and uptake of energy since the current bacteria may not be very good at processing Food B. An example of this is that dogs and cats that are suddenly switched from one brand of food to another brand (because the bag of food ran out) frequently develop diarrhoea and gut discomfort, whereas pets that are slowly transitioned over a number of weeks do a lot better. Also, trying to eat red meat after many years of not eating it at all is a really unpleasant experience.

This could potentially explain how many people who diet for weight loss for the first time report experiencing great success initially, regardless of what the new chosen diet actually is (eg. Atkins, paleo, salads, smoothies, potatoes…), but later seem to “plateau” and even gain the weight back after a while, despite sticking to the diet and exercise plan.

A good scientist would collect a faecal sample before, during and after dieting, for analysis.

13

General Science / Re: What are we going to do to the inhabitants when we find another planet?

« on: 30/05/2017 15:20:23 »

Really? From "inhabitants", you read "highly intelligent life forms (i.e. a civilization), not just life"? That is quite the imaginative extrapolation.

Sorry, I am just not fortunate enough to live in whatever utopia you reside in. But I work with suffering animals everyday, as well as the people who are quite content to allow them to suffer in the interest of their own hip pockets.

Your attitude towards "lower life forms" (whatever that means) is a perfect example of why humans cannot treat others well, or even as equals, when they differ by species, by race, by gender, by educational status, by socioeconomic status, and eventually, by planet of origin.

14

General Science / Re: What are we going to do to the inhabitants when we find another planet?

« on: 30/05/2017 10:39:48 »

We have non-human species on this planet that we already fail to treat well, let alone non-Earth non-humans. Anti-slavery laws and anti-murder laws only apply in the context of human-human interactions (in certain countries). Given that we have a tendency to treat non-humans on Earth as inferior, as being of a lower priority to ourselves, as having less 'rights' to humane/decent treatment, and that we even deny their ability to feel pain, suffering, empathy and other emotions (refer to invertebrate animals, fish, plants, bacteria, protozoa etc.), I wouldn't expect humans to treat non-humans from another plant with any more decency than we do to, say, a farm animal.

15

Plant Sciences, Zoology & Evolution / Re: What causes seagull circling behaviour?

« on: 30/05/2017 10:22:29 »

Are we talking silver gulls when when we say "seagulls"?

Without being able to observe the exact circumstances, it's a bit hard to say what is going on. I would guess that they have likely been conditioned to think "food" when they see humans (through many people feeding them previously), and they are surveying you for goodies from overhead. Alternatively, they could think that you are running from a potential danger, perhaps a predator, and that they should be on the lookout for whatever is causing you to run. Or if you happen to be running close to their breeding grounds, that would be another reason for the adults to keep a close eye on you.

Perhaps not in silver gulls, and perhaps not from just the heat energy given off by a running human, but some of the larger seabirds (some albatrosses and larger gulls) are extraordinarily efficient at maintaining flight on a just bit of rising warm air current. They may get so much uplift from the rising air, that they essentially catch a "free ride", hardly ever needing to flap their wings.

16

Plant Sciences, Zoology & Evolution / Re: Do animals know they will die?

« on: 27/05/2017 08:43:29 »

Why wouldn't they be aware of those things? The would still experience illness, hunger and shortage of resources (food, water, shelter, nesting materials). They would still potentially see deaths that occur around them, and experience the loss of family members/mates. They wouldn't have previously experienced death for themselves, but then, what living animal has?

17

Physiology & Medicine / Re: How infectious is ringworm?

« on: 22/05/2017 16:48:40 »

So do you do that as a "while you wait" service? And would you do that, or do you have someone else who can look at and prep slides while you keep seeing cases? Otherwise don't people end up waiting ages, or are you pretty nifty with a stain and microscope these days?!

We usually have 15 or 20 minute appointments. Or if you work for a cleverly-managed practice, you might be lucky enough to have 30 minute appointments for issues that are known to require multiple tests or long discussions.

I usually just explain that I'll be taking samples to look at under the microscope. After collecting the samples, I'll excuse myself from the consult room for a few minutes while I stain them up, examine them, and hopefully return with an answer and a treatment plan. I really like the time I get to spend looking down the microscope, because I get time to think alone without the client interrupting me with random questions, like how long they should cut their dog's nails...

18

Physiology & Medicine / Re: How infectious is ringworm?

« on: 22/05/2017 14:47:55 »

I always have to make a sheepish joke about the sticky tape, because it really is the least technical-looking thing I could ever do!

19

Physiology & Medicine / Re: How infectious is ringworm?

« on: 22/05/2017 14:46:17 »

Almost all veterinary surgeries would have a standard light microscope, microscope slides, some basic stains, a Wood's lamp, cotton swabs, and some sticky tape. Some will carry in-house fungal assays (which is usually just commercially prepared Sabouraud's dextrose agar with a pH indicator) to do an initial culture over a week, while others would send the sample directly to the lab.

The nature of veterinary practice is that clients expect a diagnosis on their first visit and they usually want it by spending as little money as possible; which means a lot of testing is done in-house during the space of a normal consultation. On average, in general practice, I would probably be doing microscopy for 50% of medical cases, and other lab work maybe 30% of the time (mostly skin and ear cytology, blood tests, blood smears, faecal exams, and urine exams). I would say that it's standard practice (ie. expected by the veterinary boards) here to do some kind of diagnostic work up, and in an increasingly litigious society, it's wise to have a demonstrable diagnosis behind a treatment plan. It's just a normal part of the day. Time is always an issue... Not everyone would do it that way.

In the cases where clients refuse to spend any money on any diagnostics, then yes, shampoos and creams are used. And the shampoos are usually safe enough to use on an initial treatment trial basis. But the trouble is, if the diagnosis is wrong and the shampoo doesn't help, people get really angry... Or they never come back for a follow up and the animal suffers for a prolonged period of time.

20

Physiology & Medicine / Re: How infectious is ringworm?

« on: 22/05/2017 13:18:46 »

So how do they present? Like dandruff?

Well, sometimes, just some vague, patchy hairloss or thinning. Sometimes itchy, sometimes crusty or flaky, sometimes greasy, sometimes red, sometimes with papules, sometimes fluorescent under UV light. To diagnose it, you either need convincing UV fluorescence, trichograms (hair pluck microscopy), skin scapes (cytology), fungal culture, or all of the above.