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MALNUTRITION
Technically speaking, malnutrition refers to both overnutrition (obesity), as well as undernutrition (inadequate diet or starvation). But, for the purposes of this section, we will be dealing with undernutrition. After all, we don't see too many obese flying-foxes out there: at least, in the wild. The word malnutrition hereafter in this section will be used to refer to "undernutrition". Malnutrition simply means that the body is not getting enough nutrients; that the body's needs are not being met by nutrient intake - so the body starts to break down and feed upon itself. When residual carbohydrates are exhausted, the body then naturally utilises any fat reserves, but once these too are exhausted, the body starts to break down and feed upon its own protein (catabolism). Once this happens, the animal is in very serious trouble. Nothing is sacred: even bone marrow is scavenged and broken down as a food source by the body; with resultant reduced capacity for new blood cell production. Malnutrition may result from an inadequate or unbalanced diet, digestive difficulties, absorption problems, simple starvation due to localised flowering or fruiting failure (as in 1998, 2000, and 2007), or starvation due to a condition stranding the animal in a tree - unable to fly and feed itself. Again, although malnutrition can technically occur from just one vital mineral or vitamin being absent from the diet, for the purposes of this section, we will be dealing with undernutrition - starvation.
Note the gaunt angular facial features. The problem with starvation is that it can cause at best, a minor hiccup, to at worst, irretrievable breakdown, with subsequent failure of vital organs such as kidneys, liver, and heart. In babies and juveniles, the primary cause is of course orphaning. No mother - no milk. Some of the worst cases of starvation we see are with juveniles aged 12-15 weeks (usually found within a 2 kilometre radius of the colony). It is assumed that these youngsters have either strayed too far before being ready - and then got into trouble, or have left the colony in desperation to feed when mum has not returned due to misadventure. In adults, undernutrition can be caused by seasonal starvation, but much more commonly caused by another condition, such as a fractured humerus or infection, which has now rendered them unable to fly, and therefore to feed. This is a very complex subject - because it is not just about giving them a big bowl of fruit to make everything all right again. In fact - doing that on day one, may do more harm than good, and may well even kill your flying-fox outright. Malnutrition may also in rarer cases be caused by serious underlying disease, tumours, physical injuries to the digestive tract, or parasitic infection. There is also one more known cause of malnutrition in orphaned baby flying-foxes, and perhaps this cause is the saddest of all - inadequate human foster care. SIGNS - OBSERVED & CLINICAL: Malnutrition can lead to, or be found in conjunction with, a whole range of other conditions, ranging from dehydration, to anaemia, to kidney failure, to infection, and broken bones. Apart from orphaned babies, malnutrition is very rarely the primary cause, but rather the result of the primary cause. For example, the flying-fox pictured above did not come down because he was malnourished - severe infection to the upper arm and neck (very likely from predator attack), and the resulting increasing weakness, saw him unable to leave the tree he was found in - so unable to feed, he became malnourished. So how do we know the animal is malnourished? What do we look for? Depending upon severity, signs range from no visible symptoms at all, through to an animal that is completely emaciated in appearance. The combination of several of these signs together would indicate malnutrition:
Veterinary attention may be needed to do blood analysis. Comparisons here Note that most animals will not show all of the above signs, but rather a selective combination of. Also note that many other signs may present, due to the primary cause - for example; broken bones, respiratory infection, abscesses, mite infestation, et cetera.
Note his wasted skinny body and sunken eyes. He was a staggering minus 114 WFA TREATMENT: IMPORTANT NOTE: what follows hereafter relates only to juvenile (weaned), sub-adult, and adult flying foxes. Malnutrition in babies is covered separately here Treatment for malnutrition is divided into three stages:
1. TREATING THE PRIMARY CAUSE Firstly, we must treat the primary cause. This is paramount, for without treatment for the condition that led to this situation in the first place; there will be either no improvement, or more likely, a continued deterioration. Typically with flying-foxes, this will involve such things as treating for infection, broken bones, trauma swelling, open wounds, and/or shock. Also, flying-foxes presenting with severe malnutrition will typically be hypoglycaemic, (lack of sugar in the blood), hypothermic, and dehydrated. These three conditions must be treated before attempting to feed. Animals that are very weak should not be allowed to hang. Complete bed rest for the first 1-5 days is highly recommended. Bed rest is covered here HYPOTHERMIA: Most animals coming in with malnutrition will be hypothermic. Such animals have exhausted all internal sugars and fats which normally fuel body heat generation, and many adults, let alone babies, will have lost the ability to thermoregulate. We must warm these animals before attempting to feed. Hypothermia and treatment is covered in depth here DEHYDRATION: Unless the animal has been marooned in a 5-day tropical deluge, all incoming flying-foxes with malnutrition will be suffering from dehydration - ranging from mild through to severe. Trying to feed a severely dehydrated animal can kill it, and dehydrated animals cannot absorb or properly assimilate nutrients. We must rehydrate these animals in the first instance. Dehydration and fluid therapy is covered in full here HYPOGLYCAEMIA: Upon rescue, all incoming flying-foxes with malnutrition will be suffering from hypoglycaemia (low blood sugar). You know how bad you feel when you have not eaten for a while and your blood sugar drops. Now multiply this by a factor of "X". A flying-fox stuck in a tree for many days has a blood sugar level ranging from very low, through to near fatal levels. All sugars and fats have been exhausted and the animal's body is now feeding upon its own protein (catabolism of muscle mass). With lack of sufficient blood glucose to provide the energy needs of the brain, hypoglycaemic shock and death will occur. Just as with emergency first instance treatment for starving kids during famine, we must hit these animals with "sugar water" fast. This is covered in the initial nutrition section below. ANTIBIOTIC TREATMENT: It is highly recommended that all animals coming in suffering malnutrition are routinely given a course of broad-spectrum antibiotics. This is because most of these animals will have infection or multiple infections, both seen and unseen, due to tissue breakdown, oedema, septic shock, and reduced immune system response. Early treatment is vital to help with nutritional response, prevent further damage, promote recovery, and ideally to prevent mortality. CLAVULOX PALATABLE DROPS ® by Pfizer, an amoxycillin based antibiotic containing clavulanic acid, is a broad-spectrum antibiotic, which combats a whole host of "nasties" not touched by amoxycillin alone1. It is safe to use for extended periods, has a wide dosage latitude, and has very few side effects. DOSE RATE (PREVENTATIVE) (CLAVULOX PALATABLE DROPS ®):
Given at the rate of 10mg amoxycillin trihydrate plus 2.5mg clavulanic acid per kg bodyweight; which equates to: 0.2mL per 1000 grams bodyweight. (0.02mL per 100 grams bodyweight) of made up preparation. Administered orally: twice a day for 5-7 days (longer if needed). Vet to recheck after 3 days and change medication if no improvement observed. Pre-existing infection will need cover ranging from 8-10 days for respiratory tract, through to 6-12 weeks for advanced osteomyelitis. Always consult with your veterinarian in cases of pre-existing infection. Infection is covered in detail here PNEUMONIA & PULMONARY OEDEMA TREATMENT: Extreme malnutrition causes blood albumin to fall to dangerously low levels. Serum albumin, which is made in the liver, binds small molecules for transport through the blood, and is vitally important in maintaining osmotic pressure of the blood. Without it, fluid can leak out into surrounding tissues, causing oedema of lungs, abdomen, and joints. The severely malnourished flying-fox coming in that has a rapid, shallow, "clicky", or gasping respiration will be suffering from pulmonary oedema, or pneumonia, or both. LASIX 10mg/mL liquid ® (furosemide) by Hoechst, is a very strong loop diuretic, and works by drawing off excess fluid, and then delivering it to the kidneys for excretion. Furosemide is used to treat excessive fluid accumulation and swelling [oedema] of the body caused by congestive heart failure, hepatic cirrhosis, and renal disease, and therefore is very effective as treatment in short-term management of acute pulmonary oedema, and pneumonia. Effects should be seen within 1 hour of treatment, and last for up to 6 hours. Suffice to say, this treatment vastly increases urine output. DOSE RATE (LASIX 10mg/mL liquid ®):
Given at the rate of 1mg furosemide per kg bodyweight: In liquid form this equates to: 0.1mL per 1000 grams. (0.01mL per 100 grams) as each millilitre contains 10mg of furosemide. Given orally - once a day for a period advised by your vet. Note that your vet may alternatively advise intramuscular injection on first instance, and may also advise repeat dosing at 6-12 hour intervals, depending on severity. CONTRA INDICATIONS & SIDE EFFECTS: Caution: this treatment is not without risk, and should only be used as a last resort on veterinary advice. There is a very real danger of both kidney damage, and dehydration; which must be monitored for. There is also a danger that this treatment will actually worsen kidney function in compromised animals. Furosemide can also strip the body of potassium, so add potassium rich bananas to diet during recovery treatment. Furosemide may impair kidney function when administered together with non-steroidal anti-inflammatory drugs (NSAIDs) such as METACAM ® Pneumonia and pulmonary oedema are covered in depth here 2. INITIAL NUTRITION Note: it is completely pointless starting nutritional treatment until we have dehydration and body temperature back under control, because both severely inhibit nutrient absorption. Flying-foxes presenting with severe malnutrition will typically be hypoglycaemic, (lack of sugar in the blood), hypothermic, and dehydrated, and as such, just giving the animal a big bowl of fruit because it is starving is not a good course of action, or could even be fatal. This animal will be incapable of digesting and assimilating complex carbohydrates and proteins, due to impaired liver and intestinal function. Sudden food intake risks heart failure, and dehydration affects absorption of nutrients. Until the animal receives readily available energy, and a boost to blood serum proteins, it will not be able to utilise nutrients in any normal food given, and solid food must be avoided during these initial stages. Set out below is a three-stage process providing ideal first stage nutrition. They are set out in a logical order because a hypoglycaemic flying-fox cannot assimilate proteins. Do not give big meals; no matter how hungry they are, as these animals have impaired liver and intestinal function. The trick here is "little and often". These mixes are best fed intensively from a bare syringe with short piece of oxygen tubing attached. ON INTAKE - FIRST 4 - 6 HOURS (AND AFTER REHYDRATION): 10% GLUCOSE SOLUTION:
Small frequent drinks. This combats both dehydration and hypoglycaemia FOR THE FIRST 24 - 48 HOURS AFTER INTAKE (AND AFTER REHYDRATION): STABILIZATION MIX:
Once lapping, this mix now provides a very high energy to protein ratio "kick-starter" packed with easily digestible sugars and proteins. Our aim is to give small frequent meals of no more than 10-20 mL; every 2-3 hours (ideally right through the night for the first 24 hours). We need to get a minimum of 80mL of this mix into our adult flying-fox per day. Note: if the animal is so incapacitated that it cannot even take the above mix, then keep them going on the 10% glucose solution until they can. Offer small frequent drinks by hand - as much as they will consume. Remember, an ironic sign of malnutrition is actually lack of appetite. Caution: no matter how hungry - do not give larger meals for at least 48 hours. AFTER THE FIRST 2 DAYS, AND UP TO 10 DAYS, DEPENDING UPON CONDITION: ADAPTED LEADBEATER'S POSSUM MIX:2 To make 900mL:
In your blender, first add some of the water, then the other ingredients, and then the rest of the water to make up a 900mL mix. We need a lovely smooth consistency, which will freely pass through the syringe. Keep refrigerated. This mixture will last for up to a fortnight in the fridge. This mix still provides plenty of energy, but now gives more complex proteins and carbohydrates (in the required 1:9 ratio), in an easily digestible form. This recipe also supplies high levels of potassium, magnesium, and zinc: three elements that malnourished animals are dangerously short of. Again, we do not want to overload the stomach and digestive system, but can now move to 20mL feeds, every 3-4 hours, aiming for a daily intake of 100-200 mL. Caution: these mixes are intended for severely malnourished flying-foxes only, and not recommended for otherwise healthy flying-foxes in care. They are far too high in carbohydrate (sugar) for normal use.
Note the shaved patch on his neck. This was to allow incision and drainage of a large abscess. Deep infection stranded him alone into a tree in the first place. Severely weakened, and unable to move on, he was stuck there in that tree - slowly starving. 3. RECOVERY & REHABILITATION As normal function improves, the natural appetite will return (other factors excepted). This indicates that infection is coming under control; the liver is successfully metabolising nutrients; and other metabolic abnormalities are stabilising. We now enter the normal rehabilitation phase. NORMAL FEEDING: As we progress to normal feeding, we still need to be aware that sudden large amounts of food can be detrimental - in extreme cases, causing heart failure. Our transition needs to be slow and gradual. Depending on the severity of malnutrition, soft fruit can be offered by hand sometime towards the middle to end of the first week, gradually progressing over the next few days to a more normal diet, but keeping up the liquid supplement as well for at least 10-14 days. The ideal first soft fruit is without doubt - custard apple. This fruit is soft, sweet, packed full of goodies, and will tempt all but a dying flying-fox - in fact I probably need to correct that last statement. It is so beloved by our furry patients, that it will just about tempt them back from the dead. Unfortunately, it is only available for a limited season. Ripe banana, pawpaw, grapes, melons (water, honeydew, and rock), peaches, and ripe pears can also be tried. Whilst banana and paw-paw are not recommended in large quantities for healthy flying-foxes, due to their inability to separate juice from pulp with these two fruits, what we are talking about here are severely compromised animals. We need to get them eating, long before they have the strength to chew fruits such as apple. Experience and advice on diet from coordinators and/or veterinarians is highly recommended. Once eating well, we can move them onto the normal adult diet covered here With recovery well underway, and once the animal is clearly gaining strength, it is now beneficial to allow it the company of other bats. This will help to promote normal activities and social interaction, give our patient much-needed stimulus, and give it an unseen psychological boost. In our organisation, all intensive flying foxes are housed indoors on clothes airers in a dedicated room, allowing constant observation and supervision, with permanent care companion animals brought in when needed. Regardless of whether we use airers or an outside cage, what is vital here is that our patient is constantly monitored through his or her recovery process. We really know that recovery is well underway when the animal is eagerly self-feeding, doing normal "batty" things, and gaining weight. Bear in mind that during the first few days of recovery, these animals may not gain weight at all, despite adequate food intake. This is often because oedema fluid is being lost while normal body tissues are being regenerated, and it can take a while for the liver to "kick in". If in doubt, a blood test and analysis by your vet will help reveal that all is on track. Failure to respond to normal treatment must be looked at by your veterinarian. NOTES ON REHABILITATION & RELEASE: Malnutrition is a very debilitating condition; there is no magic quick fix, but rather a slow and controlled rehabilitation regime. As such, we need to monitor our patient for quite some time, and should be in no rush to release until we are satisfied that this animal is 100% recovered - and then some. Just putting on weight again and feeding well, is not good enough. These animals came in suffering from unseen complications to normal organ and body processes. Damage may have occurred to heart, liver, lungs, kidneys, and immune system. There is a very real danger that the outwardly recovered animal is still repairing, and that if returned; and thus having to cope with the wild too soon, may relapse into a life-threatening state once more. Give them plenty of time to recover. I would not personally recommend releasing animals that have recovered from severe malnutrition for at least 4-6 weeks after full recovery is observed. SEASONAL STARVATION Mother nature usually provides a bounty of food, and in most seasons, the combination of sequential flowering and fruiting provides good year-round nutrition for flying-foxes. In some years however, it all goes wrong. Extensive food shortages were documented in the spring of 1998, late winter/spring of 2000, and the winter of 20073. By far the worst affected in the latter were juveniles and sub-adults (particularly blacks), as extensive areas of the east coast failed to flower. This was in combination with many late born blacks (meaning they were too young), and a really cold June and July. In the winter of 2007, during what is normally a quiet period, many groups were snowed under with rescue calls. Young blacks were constantly reported as: not returning to camp; hanging alone in trees during daylight (particularly Cocos palms and citrus); eating during the day; flying around during daylight; getting harried by birds; roosting on washing lines, or in low citrus shrubs; and collapsing exhausted and dying on the ground. In two recorded cases, one was reported roosting on a shovel, and another on a plastic garden chair - both in daylight. Desperate animals in Brisbane and the Gold Coast were even scavenging on the ground for fallen berries, and even attempting to eat grapefruit and lemons. Many live ones either on the ground, or low down in trees, were surviving, only to receive fatal wounds from dog attack. Also, at least two documented cases showed live flying-foxes being dragged by cats. It appears the worst affected area was southeast Queensland (Brisbane and the Gold Coast), where most had to be euthanased due to horrendous injuries from dogs. These starving juveniles and sub-adults were refusing to leave the only food source they could find, and then too exhausted and weakened to leave, were staying in situ until falling to the ground. Very sad and harrowing for rescuers, as many of these animals cannot be successfully caught high up in palms - leaving the would-be rescuer with a strong feeling of helplessness. There is nothing that wildlife carers can do during these shortages to actually alleviate the shortage; all we can do is to make sure that once rescued, the animal receives the best care and treatment we can give, and then hold until the situation improves. It is pointless releasing such animals too early, if all we are doing is putting them back out there to an "empty larder". THE GOOD NEWS: Many of these malnourished flying-foxes respond very well to the diet and nursing guidelines covered above, and then go on to a full and speedy recovery. Our little 12-week-old "living skeleton" shown at the top of the page is shown again below. Just move your mouse over the image to see what he looked like just five days into his recovery.
This lovely little guy was aptly named "Starvin Marvin" (yes - I too have watched Pythonesque American bad taste cartoons). His full story is here Section last updated: 27.07.2008 10:50 AM
1. Bacteria with a beta-lactamase enzyme that breaks down amoxycillin rendering it useless except in the presence of clavulanic acid. 2. Adapted from Michael Kidman: Melbourne Zoo (and courtesy of: Marjorie Beck) - further adapted by author to achieve the desired 1:9 protein to carbohydrate ratio. 3. Peggy Eby. Refs: Suzanne Grzegorski. |
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12-week-old juvenile, nearly at the point of death from
starvation and dehydration.
A severely malnourished adult black flying-fox
just after rescue.
This starving juvenile looks more like a stick insect than
a flying-fox.
Malnourished black flying-fox two weeks into recovery enjoying
his smoothie diet.
A magical transformation. |
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