The appearance of Stickfast Flea as far east as Narrandera has directed attention to this parasite, and as its ultimate spread to all parts of New South Wales would seem to be only a matter of time, a few notes on it might be of interest. These will not recapitulate the information already circularised, but will consist of additions which might be of value to others in their efforts to detect the flea, together with some comments on control.
APPEARANCE OF FLEA.
In connection with the recognition of the parasite, it is noted that some articles on the matter appear to assume that the readers will gather from the name that the insect in question looks like a flea. However, experience here indicates that the general public has not the slightest idea of what a Stickfast Flea looks like, and therefore it might be as well to mention at the outset that the Stickfast Flea is a true flea and has the general appearance of one. It belongs to the same order (Siphonaptera) as other fleas, but to a different family (Sarcospyllidae). It is, however, considerably smaller than the other more commonly encountered types of fleas, the specimens seen on an infested host varying in length from one-sixteenth of an inch to one-twelfth of an inch. With regard to colour, this generally is given as being from light to dark brown, but the big majority of specimens seen in this District have been the same colour; namely, a slightly reddish dark brown. However, colour variation from light brown to black has been observed. The flea also has a shiny appearance, particularly noticeable when a mass of them is seen on an infested fowl. A marked distinction from other types of fleas exists in that when seen on the host the flea is not moving from place to place, but remains firmly attached to the skin even when touched. Nevertheless, the fact that the parasite is alive is quite obvious, and an undulating type of movement is noticeable when the fleas are en masse. The flea can be detached from the host, this requiring quite a strong pull, and when detached in efforts can move and hop in the manner of other fleas.
In efforts to locate the flea a number of points require to be kept in mind. Firstly, it is mentioned that there are several varieties of Stickfast Flea, which are indistinguishable macroscopically from one another. These include Echidnophaga myrmecobii, a parasite predominantly of rabbits, which has been present in New South Wales for many years, and Echidnophaga perilis. It appears, however, that none of these other types of Stickfast Flea infest poultry, and if a bird is found to be infested with a Stickfast Flea it can be assumed to be Echidnophaga gallinacea. On the other hand, this assumption cannot be made where the flea is found on animals and microscopic examination becomes necessary to determine the point. Experience in the Narrandera District supports this; all fleas collected from poultry having been E. gallinacea. while specimens collected from dogs and cats have included both E. myrmecobii and E. gallinacea. E. perilis so far has not been encountered.
SITES OF INFESTATION.
Fowls: In poultry the sites of predilection are the unfeathered portions of the head, particularly the comb and wattles. Fleas also are seen quite commonly on the ventral aspect of the beak. In birds which are moulting, or on which for any reason feather density on the neck is not as great as usual, patches of fleas may be seen extending down the neck. Occasionally fleas might be found on other non-feathered portions of the body, but in the writer's experience they are not found in such locations except in fowls also carrying a head infestation. In inspecting fowls, until one becomes familiar with the appearance of the flea, small spots of dried blood on the comb often appear suspicious, as they somewhat resemble the parasite in size, shape and colour. However, their nature becomes apparent when rubbed from the comb.
Cats: Most articles on this subject give "between" the ears as the usual site, but during inspections here fleas have not been found in that position but on the hairless parts inside the ears and around the mouth. In examining the ear the small pouch at the base of the posterior border of the auricula requires inspection, as infestations have been seen which would have been missed if this pouch had not been examined. So far fleas have not been observed in the feet. Cats appear to be playing a big part in the spread of this parasite, as on a number of occasions the only infested host found on the property was the family cat.
Dogs: The most favoured area in these animals is on the feet, "between the claws" being quoted as the commonest site of infestation. However, if this wording is taken too literally and inspection confined to the extensor aspect between the digits, many light infestations would be missed, as fleas have been found frequently on the flexor aspect of the metacarpus or metatarsus. i.e., between the metacarpal or metatarsal pads and digital pads, when none was seen on the extensor surfaces. The parasites also have been observed in the ears, around the eyes, on the lips, inside the thighs and on the abdomen.
Methods of control adopted in this District have been along the lines of Departmental recommendations, and have consisted of attention to hygiene and the treatment of stock and premises with various insecticides. Such methods have included the following:—
(a) Neatafoot Oil. This substance kills the fleas when applied to them on birds or animals, but it has no residual deterrent effect and reinfestation commences soon after treatment. It also has the additional disadvantage of causing some scalding when applied to poultry in hot weather.
(b) D.D.T. in kerosene. Spraying with a four per cent. solution has caused marked reduction in flea infestation in treated premises. Where the spraying has been carried out with great thoroughness the reduction in some cases has reached the stage of apparent eradication. This solution is not suitable for application to birds or animals as toxic results always have followed its use on them.
(c) Potassium sulphurata and Derris. Solutions of these have been used for the treatment of dogs; reported results being variable. However, no supervision of their use has been carried out, and it is not known whether the poor results obtained were due to the ineffectiveness of the materials or the inefficiency of the users.
(d) Five per cent. sulphur in mash. This was used on one commercial poultry farm but caused a rapid drop in egg production almost to nil; and its use was discontinued by the owner before any estimate could be made of the effectiveness of the procedure.
(e) Flooding. On one Irrigation Area property the owner was confronted with a heavy ground infestation under a large low built shed which rendered eradication attempts by D.D.T. spraying and other means ineffective. The area then was flooded; the result being apparent eradication.
(f) Watery preparations of D.D.T. The appearance of these, in the writer's opinion, has reduced greatly the difficulty of control on large commercial poultry farms. Prior to their advent, D.D.T. in a form suitable for application to poultry was not available, and the materials which were used, such as Neatsfoot Oil, had no subsequent deterrent effect. Where flea infestation was heavy, therefore, frequent catching and handling of the birds was essential. In addition, more attention to hygiene in an attempt to reduce ground flea population was necessary than appears to be the case where D.D.T. can be applied to the fowls.
In an attempt to discover the value of these preparations a trial was commenced in November, 1946. The site selected was a backyard poultry run which, on the date of commencement (29th November), contained 17 fowls; all carrying a heavy head infestation. Prior to that date no control measures of any value had been attempted by the owner.
One pound of a proprietary D.D.T. preparation was used and made up with 21 gallons of water. This mixture, according to the makers, represented a 2 per cent. D.D.T. dispersion. Each bird was caught and its head and upper parts of the neck immersed in the dispersion, care being taken to keep the beak closed. When the operation was completed the rest of the mixture was applied to the floor of the fowlhouse by means of a bucket and stirrup pump spray, the total area of floor covered being 300 square feet. No other control measures were adopted then or subsequently. It is mentioned also that these birds had the run of a yard 50 feet by 50 feet which was not treated in any way.
Periodical inspections of the birds have been carried out from time to time, with the following results:—
|Date of Inspection||No. of Birds Infested||Total No. of Fleas found at Inspection.|
It is mentioned that no controls were used in this trial, but as the above dates covered the height of flea activity in the District and no diminution in infestation occurred in untreated stock in the vicinity, it seems reasonable to ascribe the results obtained to the treatment. Further inspections are to be made, but it would appear from the above that, even on an initially heavily infested property, effective control (from the poultry farmers' point of view) can be achieved by carrying out the above operation twice, or possibly once, during the warmer periods of the year.
(g) Gammexane and D.D.T. dusts. Claims have been made that effective control can be obtained by dusting either of these insecticides on walls, floors, nests and roosts without treating the bird at all led a trial of this method using each of these insecticides has been commenced in this District. No observations have been made yet, but if the claims are substantiated in the field a further advance has resulted, as the most troublesome feature of control, the catching of the birds, will have been eliminated.
(NOTE:—Echidnophaga perilis has been found on a dog at Wellington. This flea is very similar in most respects to E. gallinacea, but the natural hosts of perilis are rabbits, dogs, foxes, etc., and not birds; although the latter can be infested. The infestation with E. perilis is stated never to become as heavyas with gallinacea, and it does not cause nearly so much damage.—Editorial Committee).