There are many parasites that infect pigeons. It is beyond the scope of this book to discuss all of them in detail. The most important and most commonly encountered parasites are: roundworm, hairworm, tapeworm, the external parasites (lice and mites) and coccidia.
Worms
Worms are a primary and serious parasite and it is important that they are completely eradicated for the birds to perform at their best. They weaken the bird, meaning that race performance cannot be optimal. They also increase vulnerability to other secondary diseases, such as canker and respiratory infection. There are three common intestinal worms: roundworm, hairworm and tapeworm.
Roundworm and Hairworm
These worms live in the digestive tract of the pigeon and release eggs, which are passed with the bird’s droppings. After several days in the environment, an egg becomes infective and then, if accidentally ingested by a pigeon, hatches inside the bowel and grows into a new worm. Hairworms can also have what is called an indirect lifecycle, where infective eggs are ingested by an intermediate host such as a beetle or slug. Pigeons become infected when they eat this intermediate host. In the loft, there is no easy way for fanciers to tell whether their birds have these parasites, as the adult worms are only rarely passed in the droppings and indeed hairworms are microscopic. Worm infections are usually diagnosed by microscopic examination of a dropping sample, in which the eggs can be seen.
Treatment
A range of wormers are available. Some, such as fenbendazole, interfere with feather growth if used though moulting. Others, like levamisole, can cause vomiting and are therefore difficult to use through racing, while in some of the older drugs; for example, piperazine, worm resistance is common. These days the most commonly used wormers are the macro-cyclic lactones. This group of medications includes drugs such as ivermectin, moxidectin, selamectin and others. Of these, moxidectin is regarded as one of the safest and most effective. Moxidectin is commonly used to treat hairworm and roundworm.
Moxidectin (2mg/ml) is available as a clear fully water-soluble liquid that, when diluted in the drinking water, is readily taken by the birds. The dose is 5ml per 1 litre of water for 24 hours. It is effective and has a wide safety margin. In particular, it is safe to use during racing and moulting. It should not, however, be used in birds that are breeding and have unfeathered chicks in the nest. Chicks can receive a large dose of the drug via the parents. This can interfere with their ability to lift their head to be fed by their parents. This is reversible, but can compromise their growth and mortalities have occurred.
Moxidectin does not cause nausea and vomiting as many older worming preparations do, and so the birds can be fed and loft flown quite normally. Moxidectin also has the added advantage that it eliminates any external parasites that feed off body fluid. Mites in pigeons live off blood, and so these are all cleared with moxidectin. Lice live off feather debris and bloom and so, in theory, this drug should have no effect on them but, in practice, during the three weeks following moxidectin treatment, most lice also disappear. Moxidectin is also a safe and effective treatment for air sac mites at the usual dose given above.
Control In The Stock Loft
The stock loft should be completely free of worms. The roundworm lifecycle can be completed in three to four weeks and so a single worming before breeding (or racing) will improve things for that period of time only. Eradication can be achieved by using moxidectin twice at a three-week interval, followed by a super thorough clean of the loft after each treatment. This removes droppings passed before medication, which may contain infective parasite eggs with the potential to re-infect the birds.
It is a good idea to have the droppings rechecked three weeks after the second worming to ensure that the parasite has been cleared. Once these parasites have been cleared, worming any new bird before it goes into the stock loft should prevent reintroduction of worms. The dose of moxidectin (2mg/ml) for a single bird is 0.25ml of the neat liquid. If it is not possible to completely and thoroughly clean the loft, moxidectin can be repeated every three weeks over a six-month period, as the longest that eggs can remain infective in the environment is five to six months. Worms can also re-enter the stock loft if the droppings of pigeons or doves outside the loft can enter. To prevent this, any external flight should either have a grid or suspended floor.
Control in the Racing Loft
It is important that the race team is free of worms before racing. The need to treat can be determined by a dropping analysis. In the absence of testing, it is better to assume that the birds are infected and treat twice at a three-week interval, followed by a thorough loft clean before the commencement of racing. With the commencement of Thursday night basketing, race unit reinfection can occur and so it is important that the droppings are regularly checked during racing to monitor this. If a positive result is returned, worming is usually done on the Sunday or Monday (when racing is on the Saturday). In the absence of testing, it is a good idea to treat the birds with moxidectin every fourth week (usually on a Monday) to clear any roundworms or hairworms that might have been picked up, in addition to any lice or mites that they might be carrying.
Worm Control and Environmental Temperature
Pigeons infected with roundworms can have up to 300 worms or more. Each female worm can produce thousands of eggs per day. The potential for environmental contamination is therefore enormous. Heavy worm egg contamination of a loft environment can lead to rapid re-infection of the birds after an effective treatment, and be a real headache for fanciers to control. Worming the birds kills the worms the pigeons are currently infected with, but if there are worm eggs in or around the loft, the birds can quickly become re-infected and, in fact, can have adult worms again in only 21 days.
During cold damp periods worm eggs can survive for four to six months in the environment, which means that worming during this time gives only short-term improvement. Conversely, during summer when the ground temperature becomes hot, worm eggs survive for much shorter periods – only four to six weeks. Worming the birds several times, three weeks apart, during this time of year is therefore much more effective at eradicating this problem.
Tapeworm
Tapeworms also live in the pigeon’s digestive tract. They have a head or scolex, which is embedded deeply into the lining of the pigeon’s bowel. Behind this head, segments called proglottids, which are essentially packets of eggs, develop. New segments are continuously forming behind the head, pushing maturing segments further and further away until, eventually, ribbons of segments trail behind the head down the bowel, with the most mature ones at the end. When fully mature, these egg packets snap free either singly or several at a time in ribbons, before passing down the bowel and out with the droppings.
Fanciers will notice either a segmented white ribbon hanging from the pigeon’s vent or, alternatively, as the segments are motile when passed, they may see small white segments wriggling within the droppings shortly after being passed, or air-dried segments stuck to the surrounding perch. Tapeworms are therefore not a microscopic diagnosis because these segments can be seen with the naked eye. Different types of tapeworm vary in size. The small ones look like white pieces of cotton trailing through the dropping, larger ones look like pieces of rice stuck on the surface of the droppings, while the largest ones appear as whitish squares up to 0.5cm x 0.5cm. Once in the environment, the eggs inside these segments are ingested by insects. These eggs hatch into infective larvae in the insects. Pigeons become infected by eating these insects.
Treatment
For tapeworvm treatment, moxidectin is combined with a second tape-worming drug – praziquantel. Praziquantel is fairly bitter and so pigeons are initially hesitant to drink it. A commonly used preparation is "Moxidectin Plus". It can be added to the drinking water at the rate of 5ml/1L or, preferably, given to individual birds at the dose of 0.25ml per bird.
A tapeworm’s lifecycle can be completed in as few as 21 days. This means that if a pigeon swallows an insect the day after worming, within 21 days it will have tapeworms again. It is therefore important to minimise the birds’ exposure to insects. In the warmer northern areas of Australia where tapeworms are common, treatments often need to be repeated every – three to four weeks.
Weevils are one of the insects that can carry tapeworm and so seed that either has or has had weevils in it (look for the little holes drilled in the grain) must be avoided. Within the loft, slaters are the most common insect carrying tapeworm. When disturbed, slaters roll themselves into balls, which pigeons then mistake for peas, because these balls are of a similar size and colour. To prevent reinfection, it is therefore best to spray out the loft with an insecticide such as permethrin, at the same time as giving a tapeworm treatment. Permethrin has a residual effect for up to four months.
Lice and Mites
The two most common external parasites of pigeons are lice and mites. Lice live their entire lifecycle on the bird, dying quickly once they are off the bird. They feed on feather debris and bloom. Mites drink blood and other body fluids and not only live on the pigeon, but also in cracks and crevices throughout the loft. Not all mites that infect the pigeon are therefore on the bird at any one time. Many live in the loft environment, hiding in cracks and crevices and, in particular during the breeding season, below nest bowls and within nesting material, only moving on to the birds and nestlings at night to feed.
Treatment
These differences mean that, to control mites, in addition to treating the birds, the loft also needs to be treated and should be sprayed with an insecticide, such as permethrin, while this is not necessary with lice. These differences also mean that medications like moxidectin, which work well against mites, only have limited action against lice if given orally. An insecticide can be used to dip or spray the birds when lice are a problem and also to spray the loft for mites. Moxidectin 2mg/ml at one tenth the oral dose; that is, ½ml/1L in the bath water (where it touches the lice) is a very effective treatment, and is convenient where large numbers of birds need to be treated.
Permethrin is a synthetic pyrethroid that is commonly used to treat lice and mites. Pyrethroids are plant-origin insecticides, which are very effective but very safe for use in pigeons.
Permethrin is used in the following three situations:
1. To dip birds to eradicate lice and remove mites on the birds – Fill a bucket, diluting 10–20ml permethrin (40mg/ml) to 1 litre of water. Use warm water and treat the birds in the morning of a warm day. Immerse birds up to their neck, fanning their wings and tail through the solution. Momentarily dip their heads below the surface. Permethrin contains a wetting agent. Addition of the wetting agent enables complete penetration by the insecticide. Immediately after being dipped, the birds are completely drenched, with the feathers collapsing on to themselves to expose the birds’ skin (this allows good penetration allowing the insecticide to flow around the birds’ skin). The birds return to normal appearance within 2 hours. Birds will have decreased bloom for approximately one week and, if flown during rain, can become waterlogged.
2. To spray the loft – This can be done in conjunction with worm treatment to kill any insects in the loft that might be carrying tapeworm, and also to eradicate mites, in conjunction with a moxidectin treatment. It can also be done before breeding to eliminate mosquitoes, flies and, in particular, red mite. Birds are removed from the section, which is then scraped clean. Permethrin (40mg/ml) is diluted 10–20 ml to 1 litre and sprayed on to the clean scraped surfaces of the loft and into any nooks and crannies. The loft will dry in 1–2 hours and the birds allowed to re-enter.
3. To treat individual birds – It is a good idea to have some diluted permethrin mixed and ready to use in a spray bottle. Any introduced birds can be quickly sprayed before being placed in the loft, as can any birds returning after being away from the loft for an extended time. The usual dilution used is also 10–20ml to 1 litre.
In summary, for mites, either treat the birds with moxidectin or spray or dip them with permethrin and at the same time spray the loft. To treat for lice, just dip or spray the birds with permethrin or alternatively medicate their bath with moxidectin.
It is worth mentioning the continuing practice of some fanciers of using older insecticides that contain carbamates and organophophates such as maldison (for example, "Malawash" and "Nikoff") on their birds. Now banned in most parts of the world, they are still (incredibly) available in some areas, including Australia. When used as a dip or spray these toxic chemicals are absorbed into the body as long as the skin is wet. Once in the body, they are quickly absorbed but only slowly excreted, leading to levels persisting in the body for extended periods. This predisposes to a number of problems, including infertility and an increased disease vulnerability. It can be hard for a fancier to relate a lot of clear eggs during the breeding season to the insecticide used months earlier. Quite frankly, they should never be used.
Coccidia
Coccidia are a fascinating group of organisms. Different species can infect not only pigeons, and in fact all birds, but also dogs, cats, sheep, pigs, cows and a range of other animals. They are, however, very species-specific so that it is only pigeon coccidia that can infect pigeons and, for example, only sparrow coccidia that can infect sparrows. There are however, several types that can infect each animal. The most common coccidia type in pigeons is called Eimeria spp.
Animals become infected by swallowing the organism’s eggs. All coccidia, once swallowed, replicate in the cells of the host, in the process causing extensive damage. In pigeons, the common coccidia, Eimeria replicates in the lining of the bowel. After multiplying here, the newly produced eggs are passed in the droppings. When initially passed, the eggs (oocysts) are thin-shelled and contain a spherical body, called a sporoblast, which looks granular. The sporoblast is an amorphous blob of protoplasm.
Once in the environment, the sporoblast within the bigger egg develops into several smaller eggs called sporocysts (there are four in Eimeria) which each contain a number of structures called sporozoites (there are two in Eimeria). Once this has happened, the egg is said to be sporolated. It is not until this has happened that the egg is infective if swallowed. This process usually takes four to five days but depends on temperature and humidity. Once an infective (that is, sporolated) egg is swallowed, the sporozoites are released and burrow into the wall of the bowel. They at first multiply asexually in the bowel cells (in a process called schizogany) but then develop into the equivalent of male and female gametes, which then ‘mate’ to produce further eggs or oocysts (in a process called gametogany) which rupture back through the bowel lining before being passed in the dropping, thus completing the lifecycle.
The significance of coccidia for us as pigeon racers is that, as the coccidia multiplies in the bowel lining, it damages the lining, interfering with it doing its job of digestion properly. This is complicated by the fact that, each time an egg ruptures back into the bowel from the lining, it causes a microscopic ‘pin prick’, allowing the bird’s blood, electrolytes and protein to be lost.
This weakens the birds and interferes with the absorption of vital nutrients. Severely affected birds develop greenish diarrhoea, are lethargic, thirsty and lose weight. Sometimes the droppings will contain blood. Race birds with even the slightest infection are not able to give of their best.
In most lofts, a low level of infection is present, and out of the racing season is regarded as normal, serving to maintain the flock’s level of immunity. In two situations, the organism can increase in number and cause clinical problems:
1. As a primary disease, where there are flaws in loft management or design that lead to high exposure to the organism – The loft must be clean and dry. A build-up in the loft is prevented by regular cleaning, with particular attention to the drinkers and hoppers. There is no place for wetness in a healthy loft; it not only enables the coccidia egg to become infective more quickly, but promotes bacterial infection.
2. As a secondary disease, where other factors weaken the bird, enabling the coccidia to increase in number and cause clinical disease – Such factors may be other concurrent disease, such as worms or, alternatively, overcrowding, excessive tossing, poor nutrition, etc.
Treatment
Coccidia should always be suspected where loose droppings appear, particularly in young birds or following wet periods or heavy training. Diagnosis is through faecal examination under a microscope. Several medications are available to treat coccidia and these are listed in the formulary section of this book. The usual medication used is toltrazuril. The dose is 7–15mg/kg; that is, 3–7mg for the average size pigeon. One brand, "Toltravet", contains toltrazuril at 25mg/ml which means the dose is 0.25ml per pigeon or 3–5ml/L water.
The drug is clear and palatable to the birds. It does, however, have a ‘dead fish’ smell which can alarm some fanciers, but this is normal. Birds need to be treated at this dose for two days and then for a further two days, five days later; that is, on days 1, 2, 8and 9 of treatment. The drug is well tolerated by pigeons and does not appear to affect race form. It can be used during breeding and moulting. Medicated birds can be fed and loft flown normally.
Interestingly, toltrazuril works by substituting for vitamin B. The parasite absorbs the toltrazuril as it would vitamin B but the drug then kills the parasite. For this reason vitamin B should not be supplemented simultaneously as it can override the drug’s effect. Particularly in the race season the short treatment time is a big advantage over other medications that need to be used for longer periods to achieve the same result. The drug can be effectively used at a higher dose rate (10–17mg per pigeon or 14ml/L) for a single day, but this higher dose does not appear to be as palatable to the birds.
Monitoring of coccidia counts by faecal examination (usually every four weeks) through the race season is a good indicator of the team’s form. Birds with elevated counts will benefit from a course of toltrazuril. In faecal samples from perfectly fit birds, no coccidia eggs are seen.